P U B L ISI S H E D B Y
National National Association Association of Underwater Underwater Instructors (NAU (NAUI) I) PRODUCT DEVELOPM ENT
Je Jed Livingstone P R O J EC T M A N A G E M E N T
Genny Sikes EDITORS
Peter Oliver Mike Mike Williams Williams WRITER
Susan Carroll REVIEWERS
Stefan Hogbom Bill Lidyoff Rudy Lutz Carl Meilahn Mike van Niekerk Joe Joe Rodriguez Stefano Ruia Mike Russell Michael Tong DESIGN AND LAYOUT
The Information Information Design Design Group, Group, Inc. Inc. PROOFREADING
Dorothy Dorothy Winkel Winkel PHOTOGRAPHY
Hjtaagflt. Hjtaagflt.
ik 1
'
JeffBozanic WayneHasson Karl Huggins Je Jed Livingstone Carl Meilahn David Meyer Tim O’Leary Scott Raish Diving Diving Unlimited Unlimited International (D (DUI) UI)
Copyright Copyright © 2000,2004, 2009, 2010 by the Nationa Nationall Association Association of Underwater Underwater Instructors (NA (NAUI) UI) All rights reserved reserved. No part of this publicat publication ion may be be reproduced, duced, stored stored in a retrieva retrievall system, or transmitted, in any form or by any means, means, electronic, electronic, mechan mechanica ical, l, photocopying, recording, or othe otherwise, rwise, without without prior written written permission from the publisher. Printed Printed in the United States of America
NAUI Scuba Diver
PREFACE NAU NAUI Scuba Scuba Diver Diver de describes the gear, skills, skills, and basic concepts concepts of scuba diving. diving. Scuba diving diving is
a wonderful adventure sport. However, ever, like like any adventure sport, sport, there is a small but real risk risk that that you you can be injured injured any any time you enter the water to dive. Even if if you do everything right, even if your equipment equipment functions perfectly, there are always so some me risks in scuba diving. When you decide decide to become a scuba diver, you must do it of your own personal desire and be willi willing ng to accept the risks of the sport. This book is is written as a reference for all all students taking the NAUI Scuba Dive Diverr certifica certification tion course. rse. If you have any questions about the conte contents nts of this book, askyour NAUI instructor. instructor. Your instructor instructor will will let you know know in which which order theywould like like you to read the the informati information on contained contained in this book book.
HOW THIS BOOK IS ORGANIZED This book is organized into the followi following ng chapters and appendixes: appendixes: • Chapter One, “Introduction,” gives gives an overview overview of scuba scuba diving, certific certification, ation, NAUI, your obligations, obligations, and rewards from this exciting sport. sport. • Chapter Two, “Diving Equipment,” describes describes the the items of gear you will ill use in scuba diving. • Chapter Three, “Diving Skills,” describes the the skill skills s you need to master to be a safe scuba diver. • Chapter Four, “Diving Science,” describes the concept of pressure and the ways it affects your body under water. The chapter also describes the immediate and cumulativ cumulative e indirec indirectt effects of pressure. • Chapter Chapter Five, Five, “Decompression “Decompr ession,, Dive Tables, and an d Dive Computers,”describes the concept of ingassing and offgassing, dive tables and their their use, the NAUI Dive Time Calculat Calculator, or, and dive computers. • Chapter Six, “Dive Planning and Recording,” describes describes long term and short term dive plan plan ning, preparing preparing to dive, conducting your dive, and recording recording your dive. • Chapter Seven, “Problem Solving,” describes describes problem solving solving and explains why it is so important in scuba diving. diving. The chapter also describes describes how to assist other divers as well well as how how to rescue another another diver. • Chapter Eight, “Diving Environments,” describes describes factors that that affect the diving environment, such as water conditions, p physi hysical cal charact characteris eristics tics of of a site, site, waves waves and surf, and tides and cur rents. rents. The chapter also describes som some popular popular diving diving areas throughout the world, marin marine e life, life, and conservation. • Chapter Nine, “Diving Activities,” describe describes s some of the different conti continuin nuing g education education courses you can take once you are a certified certified diver, and special diving diving interests you can pursue. • Appendix A, “Answers to Review Questions,” includes includes the answers to the review questions found throughout throughout the book. • Appendix B, “Being a Responsible Diver,” includes guidelines guidelines to follow to be a responsible responsible and considerate diver. • Appendix C, “Checklists,” includes checklists for dive dive planning, planning, diving equipment, equipment, and a first aid kit. • Glossary defines the terms, acronyms, acronyms, and concepts used used in this this book.
Introduction
C O N V E R S IOI O N S U S E D I T H ISI S B O O K Unless exact exact equivelents are absolutely absolutely necessary table 1shows a list list of the conversions used used in this book. The first column shows the unit unit being converted. converted. The second second column shows shows the exact con version. The third column column shows the unit to which the conversion conversion was rounded rounded for ease ease of reading throughout this book.
Table 1 : C o n v e r s i o n s Unit
Equivalent
Rounded Unit
1bar
0.9869 atmosphere
1atmosphere
1bar
14.51 poundsper square inch inch (psi) (psi)
14.7 psi
1atmosph atmosphere ere
1.013 bar bar
1bar
200 bar
2902 psi
3000 psi
2 centimeters centimeters
0.79 inches
3/4 inch inch
10meters meters
32.81 feet
33 feet feet
20 meters
65.62 feet
66 feet
1inch
2.54 centimeters centimeters
2.5 centimeters centimeters
2 inches inches
5.08 centimeters centimeters
5centimeters centimeters
10feet feet
3.05 meters eters
3 meters eters
100feet feet
30.48 meters eters
30 meters eters
1kilogram
2.20 pounds
2pounds pounds
6.5 kilograms
14.33 pounds pounds
14pounds pounds
1pound
0.45 kilograms
0.5 kilograms
4 pounds
1.81 kilograms
2 kilograms
21“Celsius “Celsius
69.8°Fahrenheit
70°Fahrenheit
80°Fahrenheit
26.67°Celsius
27°Celsius
NAUI Scuba Diver
T A B LE LE O F C O N T E N T S
Second Stage Alternate Air Sources Gauges Maintenance Additional Diving Instruments Timing Devices Dive Computers Backup Instrumentation Maintenance Buoyancy Compensators Features Types Selection Maintenance Weights Weights and Weight Belts Belts Types of Weights Weights Weight Weight Belts, Harnesse Harnesses, s, and Weighting Systems Systems Quick Release of Weights Diving Suits Dive Skins Wetsuits Dry Suits Hoods Choosing the the Correct Suit Suit for the Conditions Maintenance Acces Accesso sory ry Equip Equipmen mentt Attachment Attachment Devices Devices Knives Gear Bags Dive Flags and Floats Logbooks First Aid Kits Other Accessories Conclusion
.....................................
............................
26 26 27 30 31 31 31 32 32 32 32 33 34 34 36 36
.............................................
Preface
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. . IK
HowThis Book is Organiz Organized ed
iv
......................
Conversions Used in This This Book Book
v
................
.....................................
...................
..................................
..................................
.......................
In M o c tio n 2 4
Learning Goals What is Scuba Diving?........................ What is Scuba Certification?
.................. ................................
.....................................
...........................
...........................................
..............................................
.................
What is NAUI? NAUI Courses
..........................................
.................................
.....................................
..............................
NAUI Specialty Courses What are the Risks of Scuba? A Little Little Apprehe Apprehensio nsion n is Nor Norma mall
.........................
..................
.................................
...............
...............
Misconceptions About Diving What are Your Obligations? Attendance Health Fitness Use of Drugs and Alcoho Alcoholl What’s Next
8
8 9 9 9 9 10 10
...................
.........................
........................................
..............................................
.............................................
......................
..........................................
......................
......................
..........................................
.........................................
............................................
..........................................
..............................................
.............................
D i v ini n g E q u i p m e n t 1 2
iW m
Learning Goals Buying Equipment for Diving Basic Personal Equipment
14 14 15
Masks Snorkels Booties Fins Gloves Flotation Device Maintenance Cylinders Characteristics Valves Maintenance Regulators First Stage
15 16 17 18 19 19 19 20 20 22 23 25 25
......................................
....................
........................
..............................................
...........................................
.............................................
................................................
..............................................
......................................
36 37 37 38 38 39 40
41 42 42 42 42 43 43 44 44 44 45
...............................
..............................
..............................................
..........................................
............................
..........................................
.......................................
.................................
..........................................
..................................
.....................................
.............................................
....................................
..............................................
.....................................
...........................................
........................................
D i v ini n g S k i l lsl s 4 6 Learning Goals Snorkelin Snorkeling g Skill Skills s Preparing Your Gear for Use Donning Donning Your Your Gea Gearr Using Using Your Your Fin Fins
......................................
....................................
48 48 48 49 50
...................
.............................
..................................
T a b l e o l C o n t e n tst s
Breathing through through Your Your Snorke Snorkell Surface Diving Clearing Water from Your Snor Snorkel kel Assembling Scuba Equipment Assembling Your Scuba Unit Unit Testing Your Scuba Unit Assembling Your Weight Be Belt Donning Scuba Gear Donning Your Diving Suit Donning Your Scuba Unit Donning Donning Your Weight Weight Belt Be lt Entering and Exiting the Water Checking Checking Your Equipment Equipment Boat and Platform Entries Beach Entries Boat and Platform Exits Beach Exits Mask Mask Skills Sk ills Clearing Water from Your Mask Removing Removing and Replacing Your Mask Mask Regulator Skills Breathing Under Water Breathing Breathing with a Flooded Flooded Mask Mask or without a Mask Clearing Clearing Your Your Regulato Regulatorr Recovering Your Regulator Breathing Breathing from a Free-Flowing Regulator Orally Inflating Your Buoyancy Compensator Compensator Switching from Your Regulator to Snorkel Monitoring Your Air Supply Buoyancy Skills Checking Checking Your Buoyancy at the Surfac Surface e Descending During the Dive Ascending Safety Skills Sharing Air with Another Another Diver Diver Independent Emergency Ascents General Guidelines Buddy System
52 52 54 55 55 57 58 59 59 59 60 6l 61 62 64 65 66 67 67 68 68 68
..............
...................................
....................
....................
........................
...................
...............................
.....................
.....................
.....................
..................
.....................
.....................
....................................
........................
Communication Underwater Communication Surface Communication Handling Your Scuba Equipment in the Water Removing and Replacing Your Scuba Unit on the Surface Surface and Under Water Water Removing and and Replacing Replacing Your Weight Belt on the Surface Surface and Under Water Water Navigation Skills Natural Navigation Compass Navigation Disassembling Your Scuba Gear Conclusion
82 82 84
.....................................
..................
.......................
85
....................................
85 86 87 87 88 89 91
....................................
..............................
............................
.................
...........................................
■ l i l i K
D iv in g S c ie n c e 9 2
.......................................
..........................................
..............
.....................................
.........................
............................
69 6 9 6 9
.......................
....................
70
......................................
71
...........................
.............................................
...................................
..................
......
...........................................
..................
.....................
.......................
71 72 72 73 73 74 75 77 77 79 80 80
.......................................
.................................
..........................
.......................
......................
.....................................
......................................
........
.......................................
...................
Learning Goals 94 Direct Effects of Pressure 94 Density and Its Effects 94 Buoyancy 97 What is Pressure 101 How Pressure Effects Volume..................102 104 How Pressure Effects Density Density How Pressure Affect Affects s Air Consumption 105 Your Body 106 How Pressure Affec Affects ts Your Air Spaces 106 The Anatomy of Your Lungs Lungs 112 Indirect Indirect Effects of Pressure Pressure 116 Ingassing and Offgassing 116 Decompression Sickness 116 Nitrogen Narcosis 117 Oxygen Toxicity 117 Carbon Monoxide Toxicity 118 Thermal Effects of Diving........................119 Humidity and Temperature 120 Scuba Cylinders and Temperature Temperature 120 ...............................
................................
....................
..................
.........................................
..........................................
................
..............
..............................
.......................................
n
l e c o m p r e s s l o i i,i , D i v e T a b l e s , a n d D ivi v e C o m p u tet e r s 1 2 2
Learning Goals Nitrogen and Diving Ingassing Nitrogen
.....................................
..............................
.............................
124 124 124
NAU I Scuba D i ver
Offgassing Offgas sing Nitroge Nitrogen n Residual Nitrogen Dive Table Overview Dive Table Terms Dive Table Rules Rules Dive Table Organiz Organizatio ation n Table 1- End-OfEnd-Of-Dive Dive Letter Group Group Table Table 22 -Surface Interval Interval Time (SIT) Table Table 3 -Repetitive Dive Timetab Timetable le Dive Planning Worksheet Planning Your Dive Finding Your Letter Group Recording Your Surface Interval and Findin Finding g Your New Letter Group Group Planning Your Repetitive Dive Recording Your Your Repetitive Dive Dive Maximizing Your Underwater Time Limiting Your Dive Time Planning Your Surface Intervals Limiting Your Your Depth Special Rules Decompression Diving Cold or Strenuous Dives Flying After Diving Altitude Diving Using the NAUI Dive Time Calcu Calculat lator or General General Organization Organization Using the Calculator Dive Dive Planning Planning with the the Calcula Calculator tor Sample Problems Using Dive Computers Dive Computer Terms Terms Displays Planning Repetitive Dives Safe to Fly Indicators Logging Your Dives Dive Computer Computer Rule Rules s Conclusion
............................
..............................
..............................
.................................
.................................
........................
124 126 127 127 128 129 130
...................................
........................
............................
....................
130 131 132 133 133
..............
...........
.....................
...........
..........................
.......................................
.........................
Short Range Planning
152
Preparing to Dive
152
.............................
...................................
Conducting Conducting Your Dive
153
..............................
Site Survey
153
........................................
Emergency Plan Activity Diving Your Plan
153
.................................
153 154
.............................
..................................
..........................
...........................
..................................
............................
..........................
..........................................
...................................
Contingency Planning
154
.............................
Reco Record rdin ing g You Yourr Dive Dive.. .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... ..1 155
04867768
Learning Goals
160
......................................
134 135 135 136 137 137 137 137 137 139 139 139 139 139 139 140 141 142 142 143 146 146 146 147 147
.......................
..........................
150
.............................
.............................................
...............
....................
Long Range Planning
Diving Situations
160
...................................
General Metho Method d of Resolving a Proble Problem m
160
Heat Loss
160
...........................................
Overheating
l6l
Cramps
162
.......................................
.............................................
Entanglements
162
...................................
Disorientation and Vertigo
163
Equipment Difficulties
163
Seasickness
164
......................
..........................
........................................
Choking and Coughing
164
Air Starvation
165
Summary
165
.........................
.....................................
..........................................
Assisting Other Divers
..............................
165
Establishing Buoyancy
166
Resting and Breathing
166
Providing Assistance
166
..........................
..........................
.............................
Rescues
167
...............................................
At the Surface
167
Underwater
168
.....................................
........................................
In-Water In-Water Artificial Artificial Respiration
................
16 8
Emergencies Emergencies and First Ai Aid d
.........................
169
.............................
..........................
.........................................
Be Prepared
.....................................
Basic First Aid
...................................
Learning Goals
.....................................
150
170
CPR and Oxygen Adminis Administrat tration ion
171
Aquatic Life Injuries
171
............
Dive Planning and R e c o r d ini n g 1 4 8
170
............................
Safety Safety in Summary Summary
.................................
Responsible Scuba Diving Practices
..............
172 172
Table of Contents
Diving Environment 174 Learning Goals Physical Characteristics of a Site Type Types of Site Sites s Entries and Exits Bottom Conditions Water Conditions Visibility Temperature Moving Water and Its Effects Effects Waves and Surf Tides Currents Marine Life Animals That Bite Animals with Barbs Animals That Sting and Scrape Animals That Shock Conservation Diver Impacts Hunting Collecting ExploringWrecks Cleaning Up the Environment Boat Diving Popular Diving Areas California Cozumel Gulf Gulf Coast of Louisia Louisiana na and Texas Great Lakes Turks & Caicos Truk, Federated Federated States of Micron Micronesi esia a Galapagos Islands
......................................
.................
176 176 176 177 178 180 180 181 182 182 183 183 185 185 186 187 187 187 188 189 190 190 190 191 192 192 193 193 193 193 193 194
.....................................
................................
..............................
....................................
..........................................
.....................................
......................
.................................. ..................................
..............................................
..........................................
...........................................
...............................
.............................
..............
Leadership Courses Developing Special Interests Being a Responsible Diver
................................
......................
........................
11 1 i
199 200 201
A n s w e r s lb R e v ie w Q u e s tio n s 2 0 2
Chapter 1 Health and Fitness Chapter 2 Basic Equipment Cylinders Regulators, Alternate Alternate Air Sources, and Instrumentation Instrumentation Buoyancy Compensators Weight Belts Diving Suits Accessory Equipment
202 202 202 202 202
Chapter 3 Using Mask, Mask, Snorkel, and Fin Fins Assembling Scuba Gear Entries and Exits Mask Skills Regulator Skills Buoyancy Safety Safety Skills Skills Buddy System Communication Handling Scuba Equipment in the Water Water Navigation Chapter 4 Density and Its Effects Buoyancy Pressure Air Quantity in Balloon Air Consumption Consumption Squeezes and Block Blocks s Lungs and Breathing Indirect Effects of Pressure Thermal Effects Effects of Diving Diving Chapter 5 Ingassing and Outgassing Dive Table Rules
203 203 203 203 203 203 203 203 204 204 204 204 204 204 204 204 204 204 205 205 205 205 205 205 205
............................................
..............................
............................................
...............................
.........................................
........................
................................
......................
202 202 202 202 202 202
......................................
......................................
...........................
............................
........................................
.....................................
..............................................
............................................
...................................
....................
..........................................
...............................
.........................................
...........................................
.......................................
...................................
...............................
............................................
................
........................
...............................
......................................
................................
........................................
.......................................
....................................
................................
......................................
............................................
.........................
........................................
..........................................
W
Diving Activities 196
Learning Goals Getting Getting Involved in Cl Clubs ubs Furthering Your Education Specialty Courses The Advanced Scuba Diver Diver Course Course The Master Master Scuba Diver Course Training Assistant Specialty Course
......................................
198 198 198 198 198 199 199
..........................
.......................
....................................
...............
...................
..............
.......................
...............................
...........................
..........................
....................
....................
...........................................
...................
...............................
NAU I Scuba D i ver
Table 1 Table 2
Spare Equipment Emergency Items Personal Items First Aid Kit Checklist General Optional
205 205
............................................
............................................
Table 3 Dive Planning Planning Worksheet Worksheet Sample Problems Dive Computers Chapter 6 Long Range Planning Short Range Planning Preparing to Dive Conducting Conducting Your Your Dive Dive Diving Your Plan Contingency Planning Recording Your Dive
205 205 205 206 206 206 206 206 206 206 206 206
Chapter 7 Diving Situations Assisting Other Other Divers Divers Rescues Emergencie Emergencies s and First Aid Aid Chapter 8 Physical Characterist Characteristics ics of a Site Site Water Conditions Water Movement Marine Life Conservation
206 206 207 207 207 207 207 207 207 207 207
............................................
......................
...............................
.................................
.................................
.................................
....................................
..............................
.............................................
...........................................
213 214 214 214 214 214
.............................................
..........................
.........................
...............................
..........................
................................
.........................
............................
I
M
B
M e n 222
.............................................
................................
...........................
...........................................
.....................
GETTING THE MOST OUT OF THIS BOOK Throughout this study book there will be sections that require your special attention. The following icons are used to mark these sections.
.............................................
.............
................................
.................................
.......................................
.....................................
Diver Etiquette NAUI Respo Responsib nsible le Boat Diving Prac Practic tices es The Code of the Responsible Div Diver er
.......................................
210 210 211
Indicates Indicates that that you should take note note of the informatio information, n, because it forms the basis for the final exam.
Indicates information that will help you complete complete the workbook.
m
........
...............
Checklists 212
m aw i Dive Planning Checklist Long Temi Planning Short Term Planning Preparing to Dive On-Site Planning Diving Equipment Checklist Primary Dive Gear Additional Dive Gear
....... ..................
........ ..................
........ ..................
............ ..................
............ ..................
... ..................
............ ..................
......... ..................
212 212 212 212 212 213 213 213
©
Indicates a warning or safety information.
r
Indicates responsible diving practice.
Table of Contents
CHAPTER
MAUI Scuba Diver
LEARNING GOALS o i t c u d o r t n I
In this chapter chapter you will: • Learn the meaning of the acronym SCUBA. SCUBA. • Learn about about scuba scuba certification. certification. • Be introduced to to NAUI Worldwide. • Learn about other NAUI courses. • Be introduced to some of the risks of scuba diving. • Understand Understand your obligations obligations for attendance, attendance, health, health, and fitness. • Understand Understand why why drugs, alcohol, alcohol, and diving diving do not mix. Scuba diving diving is is the most unique adventure sport sport on earth. In the underwater world, you can watch the the deli deli cate beauty of tiny fish as they dart around a colorf colorful ul tropical tropical reef. You can experience experience the thri thrillll of swimming swimming eye to eye with with sea turtles, whales, or manta manta rays (figure (figure 1-1). 1). With With very little little trai trainin ning, g, you can shoot underwater underwater video footage that will will dazzle dazzle your family family and friends. friends. As a scuba diver, you can see history as you discover fab ulous underwater treasures treasures and lost sunken cities. Scuba diving diving is an an adventure sport you can pursue almost anywhere anywhere in the world. From the shipwrecks shipwrecks of of the Great Lakes Lakes to the the tropical tropical reefs of Australia, Australia, from the kelp kelp forests forests of Califo Californ rnia ia to the rocky coast of the Mediterranean, where there is water, there is usua usually lly div div ing. As long as you are in good healt health h and have the proper equipment and training, you can enjoy diving.
F IGI G U R E 1 - 2 . W R E C K E X P L O R I N G M I G H T B E O N E O F T H E A C T I V I T I E S Y O U W I L L E N J O Y .
F IGI G U R E 1 - 3 . D I V INI N G I N C O L D W A T E R C A N B E J U S T A S E N J O Y A B L E A S D I V I N G I N W A R M W A T E R .
Although it it might might seem that there is a great deal of informatio information n you must must learn about diving, you do not not need to be an expert to enjoy enjoy it. You can experience all all the excitement of scuba diving diving by completing completing your NAUI Scuba Diver certific certification ation course. There are are dives dives that are more advanced and challeng challenges es you can choose to experienc experience e later, but the basics basics of diving will will enable you you to begin your your underwater underwater adventures. F IGI G U R E 1 - 1 . I M A G I N E T H E T H R I L L O F S W I M M I N G W I T H LA LA R G E A N I M A L S U N D E R W A T E R !
4
Chapter 1- Introduction
To enjoy diving where you live, live, you wil willl need to to learn learn how to use the scuba equipment commonl commonly y used in your area. The equipmen equipmentt might appear appear intimidat intimidat ing at first, but it is very simple simple to use. Just Just like driving a car, you you don' don't need to understand understand every aspect of the the equipment equipment to be able to use it. Just Just remember that if you dive in other areas or pursue pursue certain certain specialized specialized type types of diving, you will will need need additional training training and equipment.
W H A T ISI S S C U B A D I V INI N G ? You might alread already y know that the word scuba stands stands for Self Contained Underwater Breathin Breathing g Apparatus. Apparatus. You scuba dive with a compressed air air cylind cylinder er or tank tank that you wear on on your back (figur (figure e 1-4). 4). The air air is supplied to your mouth through a regulator regulator that that reduces the high high pressure inside the tank tank to the same pressure as the water surrounding you. You will will hear divers divers referring to scuba scuba diving as recreatio recreational nal diving diving or sport sport diving. These terms are used interchangeably interchangeably to refer to scuba diving for for fun, as opposed sed to commercial diving diving work, which which professionals perform for pay. You might might also hear the term technic technical al diving. diving. This term refers refers to highly highly specialized divin diving g that
F IGI G U R E 1 - 5 . S K I N D IVI V I N G ISI S D O N E W I T H O U T A N Y U N D E R W A T E R B R E A T H INI N G A P P A R A T U S .
requires additional equipment and training to explore the more demanding areas of the underwater world. You will also hear the the term term skin diving. Skin diving diving involves diving wit without hout any underwater breathing appa ratus. In skin diving, you hold your your breath and and dive dive below the surface. Skin Skin diving diving is also known as free div ing or breath-hold breath-hold diving (figure (figure 1-5). Your NAUI NAUI Scuba Diver certifica certification tion course course will teach you to to become a beginning beginning scuba diver. Your instructor wil willl also teach you the the fundamentals of skin diving. Mastering the skills of skin diving will will make you you a much better scuba diver. diver.
WHAT IS SCUBA CERTIFICATION?
F IGI G U R E 1 4 . Y O U W E A R A C O M P R E S S E D A IRIR C Y L INI N D E R O N Y O U R B A C K W H E N Y O U S C U B A D I V E.E .
Because there there are no no laws governing recreationa recreationall scuba diving in most countries, countries, the professiona professionall instruc tors who work in the the scuba industry have agreed on cer tain minimum minimum standards standards of training training for sport sport divers. divers. You must meet these standards to receive a certifi certificat cation ion card. Your NAUI instructor will also add special training training specific to the the area in which you are learning learning to dive. dive. Your certificatio certification n card will will enable you you to receive receive scuba scuba diving services, services, such as renting a cylinder cylinder or enjoying a day of diving on a charter dive boat. boat.
NA UI Scuba Sc uba D i ver
o i t c u d o r t n I
Your NAUI NAUI Scuba Diver certification certification course will teach you the fundamentals fundamentals of diving. You will ill learn learn the principles principles of selecting and operating your equip ment, ment, the effects of diving diving on your body, body, and basic infor infor mation about your local local diving diving environment. environment. Once Once you have completed completed the course course and your open water cer certif tifi i cation dives, you will be qualified to dive in conditions simi simila larr to those in which which you did your open water certification dives. Different levels of diving certification certification signify special knowledg knowledge in diving. diving. After you complete the NAUI Scuba Diver Diver certification certification course, course, you you will will beeligible eligible to take specialty courses to learn about the different special interest areas areas in diving. For example, you might want to take a course in rescue diving diving or or underwater photog raphy (figure (figure 1-6). 1-6). There are also also courses in underwa ter hunting and collecting, night diving, and many many other topics. Your instructor instructor probably learned learned to dive in a course course simila similarr to the one one you are taking now ow.. In addition, your instructor instructor completed completed addition additional al leadership leadership course courses s in running running organized dives and diver rescue techniques. techniques. Before being grante granted d an instructor ce certific rtification, ation, your instructor instructor also completed a demanding demanding course in instruc instructio tional nal techniques and was required to demon strate the required knowled knowledge ge and skills skills to a panel of experienced diving instructors.
F IGI G U R E 1 - 6 . O N E O F T H E S P E C I A LTL T Y C L A S S E S Y O U M I G H T W A N T T O T A K E I S U N D ER ER W A T E R P H O T O G R A P H Y .
Your NAUI Scuba Diver Certificatio Certification n card is just the the beginning of your adventu adventures res in diving. diving. It is your license to lear learn n more about the underwater world. There is no one who knows knows everything there is to know about diving, but in diving, you’ll find much of the fun is in the learning.
W H A T ISI S N A U I ? Your NAUI Scuba Diver certifica certification tion course is being being taught by an instructor certified through the National Association of Underwater Instructors, Instructors, more commonly referred to as NAUI or NAUI Worldwide (figure 1-7). NAUI was founded founded in i 9 6 0 and is is one of the oldest and most respecte respected diver certify certifying ing agencies in the world. You can take pride pride in your NAUI certifica certification tion becau because NAUI courses are among the most most thorough, routinel routinely y exceeding minimu minimum m industry industry standards. standards.
NAUI Courses In addition to teaching the the NAUI NAUI Scuba Scuba Diver certi fication course you are currently taking, NAUI instruc tors also teach courses to to further your your diving diving education. Two of the NAUI courses you can take to continue continue your education are: • Advanced Advanced Scuba Diver Diver • Master Scuba Diver
F I G U R E 1 - 7 . Y O U R I N S T R U C T O R I S C E R T IFIF IEIE D T H R O U G H T H E N A T I O N A L A S S O C I A T I O N O F U N D B 1 W A T E R I N S T R U C T O R S ( N A U I) .
Chapter 1- Introduction
The NAUI Advance dvanced d Scuba Diver certifi certifica cation tion course improves roves your overall overall knowledge and skills skills in the water. water. It is designe designed for newly certifie certified d divers and introduces introduces you to the many different types types of activitie activities s avail availab able le to certified divers. The NAUI NAUI Master Scuba Diver certifica certification tion course course helps you acquire acquire leadership-level leadership-level academic academic knowledge knowledge and enables you to participa participate te in exciting exciting advanced div ing activities in a challenging course. Many people people find that diving diving changes their careers and even their lives. By gaining gaining diving diving experience experience and taking taking the progressive courses your NAUI faci facilility ty or instructor instructor offers, you can gain knowledge, skills, skills, and experience experience that will will prepare you you to earn your own certification as a NAUI instructor.
NAUI Specialty Courses NAUI instructors also teach many kinds of specialty specialty courses. Some of the NAUI specia specialty lty courses you can take cover: • Rescue Rescue diving • Wreck Wreck diving diving • Deep diving • Underwater Underwater photography and and video video
5
.
& P
i'':
•
-
•£ .
'■ '■
J >-?
- :
.
.< :
v
—
-
-
*
- I* *
.
it
-
-
^
^
^
-- ___ ___ :
^
■ - ■* - —
i
r •
'
..f*
F IGI G U R E 1 - 8 . S O M E T I M E S C O N D I T I O N S A R E S O B A D T H A T ITI T ISIS A D V I S A B L E N O T T O D I V E .
• Ice diving diving • Cavern Cavern and cave diving • Underwater Underwater hunting and collecting collecting • Night diving diving • Technical Technical diving diving These course courses s are fun and emphasize emphasize the practic practical al application application of the know knowledg ledge you you wil willl gain in your NAUI Scuba Diver certifica certification tion course. course. Specialty courses courses give give you the the opportunity to learn learn these exciting activit activities ies safely and faster than if you tried to accumulate the same knowledge and experience experience on your your own. The more experience experience you can gain under under the supervision of a NAUI instructor, instructor, the more comfortable and confident you will be in the water.
W H A T A R E T H E R I SK SK S O F S C U B A ? In any sport, there are risks. Scuba diving, diving, as a sport, sport, has some risk risk and and you must understand this before you become a diver. diver. Most dives are very easy. However, on every dive there is always a chance chance that you wil willl need to exert yourself yourself greatly. At times, diving diving can be very strenuous. strenuous. This is particu particular larly ly true if you dive in cold water, dive in strong currents, or make beach beach entries through surf surf (figure 1-8). As in any activity, activity, the ultimate risk in diving is of being injured or killed. Serious injuries and deat deaths hs caused by diving diving are extremely rar rare e though, and most divers never suffer any type type of mishap. mishap. However, you need to recognize that that risk risk exists. As a diver, diver, you must bewilling illing to accep acceptt this risk and take take responsibility for Expres esss your own actions. You will ill be asked to sign an Expr Assumpt Assumption ion of Risk Risk Associ Associat ated ed with with Diving Diving and Related RelatedActivi Activiti ties es which explains the risks of diving. Also, this textbook clear clearly ly explains explains each type type of risk asso ciated ciated with diving. diving. In addition, addition, your instructor instructor will explain the risks in diving in in general general and any risks that are unique to your local dive sites. If you are a minor, your parents will also have have to understand the risks you face in diving. diving. They will ill be be asked to sign your waiv waiver er and medical history>form.
NAUI Scuba Diver
A L i e A p p r e h e n s i o n i s N o r m a l Mostpeople who have not spent much time time swim swim ming in the ocean or other open bodie bodies of water have a little little apprehension about learnin learning g to dive. You might have concerns about the the strange equipment, the marine marine life, life, and the environment. This is normal normal and to be expected. Diving is seldom seldom like it is portrayed portrayed in popular films films or television television shows. Once you become a diver, you will will quickly quickly begin to spot spot the the flaws in in most of the the movies mo vies that feature diving. When you go under water, water, you will will find that most most fish swim away from divers and that humans are are almost almost always the most dangerous creatures there. There are ways to minimize minimize the risks risks in diving. By knowing the risks, risks, you can deal with them and make make the probabil probability ity of problem problems s occurring occurring extremely small. This is one major objective of your NAUI Scuba Scuba Diver certification course.
The amount amount of air you have have in your your cylinder limits the amount of time time you spend spend under water on any given dive. Divers use use a submersible pressure gauge (SPG (SPG)) connected to their cylinder to monitor their air supply and help them determine when it is time time to surface (fi (fig g ure 1-9). Just Just as a person person driving driving a car monitors their fuel gauge, gauge, you will will monitor monitor your pressure pressure gauge under under water. However, you must monitor monitor your your pressure gauge more frequently frequently than you would a fuel gauge. gauge. As an an extra precaution, most most divers divers carry either either an additional additional regulator, which allows their dive buddy buddy to to share air during during an emergency, emergency, or a total totally ly independent independent backup backup air air supply. supply. If you are a responsib responsible le and reasonably reasonably cau tious diver, the risk of running running out of air under water is very slight. Another common common misconception is that diving diving equipment is unreliab unreliable. le. Few divers ever ever experience experience an equipment equipment failure failure in diving gear that has bee been n properly properly maintained. A poorly maintained regulator is more more likely likely to freeflow freeflow and deliver more more air air than you need need than to deliver no no air air at all. all. As part of your NAUI Scuba
One of the most popular misconceptions about div div ing is that you can easily easily run out of air under water. water.
Diver certification certification course, course, you you will will learn how to properly properly care for for your equipment and inspect it before each dive. dive. Occasiona Occasionally, lly, a piece of gear might become become loose loose or go out of adjustment u under nder water, water, but you will will learn learn how to deal with with these minor nuisances as part of of the course. Another common concern is that when you are diving diving in in the ocean, you you will will always be be under under the threat of a shark shark attack. Few divers ever ever have the opportunity opportunity to even see a shark shark during during normal normal scuba dives. dives. There are special special trips trips for experienced experienced divers that have the sole purpose of seeing and photographing photographing sharks. The opportunity opportunity to dive with with these unique creatures creatures is something something rare and special. In most cases when sharks do encounter divers, divers, they show littl little e or no interest interest in the divers divers unless they have been been baited with food. food. Divers who remain calm, calm, swim slowly, and stay under water water usually usually receive little little or no attention from a passing shark. shark. They, like like most most creatures under water, wil willl leave you alone iiff you do not not
OUT YOUR DIVE TO SEE HOW M UCH AIR YOU HAVE LEFT
harass them.
C h a p t e r 1 - I n t r o d u c tit i o n
W H A T A R E Y O U R O B L IGI G A T I O N S ? As a student enrolled in in the NAUI Scuba Scuba Diver certi certi fication course, you have certain obligations.
A t t e n d a n c e You have an obligation to attend, participate in, and satisfacto satisfactorily rily complete every every classroom and water session session. Diving Diving is not complicated, but the know knowledge ledge and skills skills you learn build build throughout the the course. course. You must understand the simple simple concepts in divin diving g to be able to apply them them to the the diving diving you wil willl do in open open water. If you do not attend every train training ing session, session, your knowledge and skills skills wil willl be incomplete. If you do miss any sessions, sessions, it is is your responsibility to arrange with your instructor instructor to complete complete them satisfactor satisfactorily. ily. Be sure to take not notes es during all all classroom session sessions. Your instructor w will ill provide provide you with supplemental supplemental information that might not be in this textbo textbook. ok. In particular particular,, you will learn about about local diving diving techniqu techniques es during during the lectures lectures and open open water dives. dives. You will learn the skills of diving in a confine confineddwater setting. setting. These sessions might take place iin na swimming pool or a calm, clear clear body of water. water. Once Once you have learned the skills of diving and can demon demon strate them comfortably, your instructor will take you on a series of open open water dives where where you wil willl practice practice these skills under actual diving conditions. You will will need to complete knowledge knowledge examinations, plus confined and open open water water evaluations of your diving diving skills before fore your instructor wi willll issue you a NAUI Scuba Diver certification certification card. Even if you pass pass all the knowl edge and skill skill tests tests, but your your instruc instructor tor does does not believe that that you have the judgment needed needed to dive properl properly y or respon responsibly sibly,, it it is your instructor’s instructor’s obligation to withhold your certification. certification. You instructor will explain explain what you need need to do to complete complete your certific certificati ation on and will will help you to achieve that goal.
Health Health is the stateof being sound in body and mind and is a prerequisite for diving. To engage in diving, diving, you must:
• Have a sound heart and healthy healthy lungs. • Have clear clear ears and sinuses. sinuses. • Be free of any limiti limiting ng disease or serious ailment. ailment. • Be free of any condition condition that that can cause unconsciousness. Your instructor instructor will will askyou to complete complete a medical history form before you can partici participate pate in the water ses sions for this course. If you indicate indicate any problems problems that might affect your ab abilit ility y to dive, you wil willl be asked asked to to have a medical examination and obtain written medical approval before starting your training. Your age and and overall physical physical condition might also cause your instructor to require that you see a physician for a physical examination examination before before diving. This is for your own well well being. However, regardless regardless of a physi cian cian’s ’s opinion, a NAUI instructor may well decline to train train you if you have an absolute absolutecontraindication (a medical condit condition, ion, such as asthma, diabetes, diabetes, or epilep sy) to diving. Women have special healt health h considerations, considerations, espe espe cial cially ly during during pregnancy. pregnancy. No definitive definitive studies studies have bee been n done on on the effects effects of increased increased air air pressure on an unborn child. child. Therefore, if a woman woman is pregnant, she should not dive. If a woman can engage engage in physical activities on land during menstrua menstruation, tion, it is usually usually all all right to par ticipate in in diving. If cramps or other effects effects of menstru menstru ation lim limit it a woman’s activity activity on land, it it is best best to not not dive when when these symptoms exist.
Fitness Fitn Fitnes esss is the abil ability ity to meet the the physical physical demands of a particular particular activity. You must must be fit to dive. dive. Initia Initially lly,, this means that you need good aquatic aquatic abil ability ity,, such as being able to swim at least least 200 meters (220 yards) non stop without without fins or or other aids. This demonstrates demonstrates the the aquatic aquatic fitness fitness needed needed to be comfortable in the water. water. Later, Later, you wil willl need to develop develop fitness for using fin fins s and performing other waterskills.
Jus Justt because you are in shape for some sports does not mean that that you are in in shape shape for diving, diving, because because different muscle muscles s are use used d in different ways ways.. Playing Playing sports such as baseball baseball does not necessa necessaril rily y keep you fit fit
NA UI Scuba Sc uba D i ver
m
for diving. To be in shape shape for a particu particular lar activity activity requires requires regular participation participation in that activity. activity. The best way to stay stay fit for diving diving is to dive regular ly, or swim with mask, snorkel, and fins. Remember Remember that your ability ability to dive dive safely is decrea decreased sed by inactivity. inactivity. Before resuming diving diving after a layoff layoff of one one month or or longer, you should re-establish your skills skills and fitness by pool workouts before any open water water dives. Refresher Refresher courses offered by NAUI facil faciliti ities es and NAUI instructor instructors s also afford opportunities to polish polish skills, skills, add new knowl knowl edge to the basics, basics, and help restore fitness and skill skill pro ficiency. ficiency. Refresher courses courses are are highl highly y recomm recommended if you haven’t been been diving in a while. Divers take pride in their their health and fitness. fitness. It is essential essential to maintai maintain n your health health and fitness fitness if you want to enjoy the sport sport and reduce its risks.
Ueg of Drugs
mi A l c o h o l
Good health and fitness are important for for diving safety, but use of drugs can lead to problems under water. Substanc Substances es such as alcohol, mari marijua juana na,, and cocaine, which alter alter your physiology physiology and affect affect your ability ability to think clearly, should never be used before diving.
Any such substanc substance e would be be partic particula ularly rly dangero dangerous us if taken before before diving. Avoid taking any any over-theover-the-count counter er or even prescription prescription drugs that that recommend you not operate operate machi achine nery ry.. Even if you are on medication prescribed by a physician, physician, its effects under pr pressu essure are probably unpredictable, especially especially side side effects effects.. Complete Complete your your treatment before diving. diving. Do not drink drink alcohol before diving. If you are ill ill and do not feel feel well enough to dive dive without without taking taking a drug, you should not dive, even if you feel fine with with medication. medication. The effects effects of drugs drugs can be changed by pressure pressure in unpredictabl unpredictable e ways. Medication Medication can mask the sym sympto ptoms ms of your illness illness,, but that that illness illness still exists.
V e r i f y W h e t Y o u H a v e L e a r n e d Review the following following questions questions about health and fitness: 1. Good Good health is a requirement requirement for div diving ing because because 2. A person should ref refrai rain n from divin diving g when 3. True or False: Only people people with problems problems in their their medical history should have a physical examina tion for diving. 4. The best way to maintai maintain n fitness for diving diving is to 5. If I f you are not feeling well but medication help helps s you feel better, you should refrain from diving because ______________________________
F IGI G U R E 1 - 1 0 D IVI V INI N G I S O N E O F T H E M O S T E X C I T ININ G A N D F O N A C T I V I T I E S Y 0 0 W I L L E V E R E N J O Y .
You will will find that scuba scuba diving is one of the bes best activ activ ities that you you will will ever enjoy (figure (figure 1-10). By completing this Scuba Diver c certifi ertification cation course, you will ill beprepared to participate in diving advent adventures ures unlike anything you have experienced experienced before. Read this this bookcompletely, com plete theworkbook, and follow follow your your instmcto instmctor’s r’s directions and you will will be ready to leam how to dive.
m
OtGS
NAU I Scuba S cuba D i ver
LEARNING GOALS In this chapte chapterr you will: will: • Learn about the basic e equipment quipment you need to go skin diving. • Learn about scuba cylinders, cylinders, includ including ing types types and sizes, valves, maintena maintenance, nce, and inspections. inspections. • Be introduced to regulators and the equipment equipment usuall usually y attached to to the the regulator. • Learn about differ different ent types of diving instruments. • Understand the types of buoyancy buoyancy control control devices and how to select one that that meets your needs. • Learn about weighti weighting ng systems. • Be introduced to the many different types of div div ing suits for warmth and protection and learn how to choose oose the right right suit for your your diving diving con con ditions. • Learn about some the accessory equipment that that makes diving more enjoyable. You must use some some specializ specialized ed equipment equipment to go skin diving diving or scuba scuba diving. diving. When you first first put on on the the equipment nee needed ded, you wil willl probably probably feel awkward awkward before you enter the water. Keep in mind mind that each item serve serves a purpose rpose in the underwater environment. The gear is designed designed to to be be comfortable in the water, rather rather than on land. The sooner sooner you get in the water, the better the equipment equipment will will feel to you.
BUYING EQUIPMENT FUR UIVING You can buy diving equipment from a variety variety of outlets. However, ever, your best choice for purchasing purchasing equip ment is your loca locall dive shop or sporting goods store, if if it it has a dedicated dedicated diving section (figure (figure 2-1). 2-1). There are several reasons why you should buy your gear gear from a specialized specialized retailer, such as a NAUI NAUI affiliated affiliated dive store. These include: include: • You can see and wear the equi equipment pment in in the the store before before you buy buy it and possibly even try out simila similarr rental rental items items in the store store pool. pool. • Your local local retaile retailerr is able to help help you adjust item items s such as buoyancy compensators compensators (BCs (BCs)) and to
FIGURE 2-1. A DIVE RETAILER IS THE BES T CHOICE FOR PURCHASING EQUIPMENT.
measure measure you properly for custom-tailored custom-tailored wetsuits. wetsuits. • Local retailers can provide you you with the instruc tion needed when you purchase a specialized specialized piece of gear, such as a dive computer, video housing, or dry suit. • Your local retailer is usually able to service any gear that you buy a att their their shop. • Local retailers might rent or loan you equipment equipment while yours is in the sho shop for repair. • Your local retailer retailer is your only sourc source e for scuba scuba cylinder fills and last minute required items. Develo Develop a good relationship with with your loca locall diving retaile retailer. r. The salespeop salespeople le there there will ill be able to help you select select the right type type of gear gear for local local diving conditions and for your personal diving interest interests. s. Most newdivers divers wait until until they have have finished their course to buy all of their their scuba equipment. This is a good idea becaus because e you will will usually usually have the opportunity to to try several different different types of gear during during your course. However, most instructors w wililll require require that that you have cer tain tain personal items items of gear when you start your NAUI Scuba Diver certificati certification on course. course. These item items can include: • Mask • Snorkel • Booties Booties • Fins • Gloves
Chapter 2- Diving Equipment
B A SI S I C P E R S O N A L E Q U IP IP M E N T You can go skin diving under under optimal conditions with four four pieces of gear gear:: • Mask • Fins Fins • Snorkel • Flotati Flotation on device Because you wear most pieces pieces of dive gear directly directly on your body, the comfort comfort and fit fit of each item is extremely important.
Masks If you have ever opene opened your eyes eyes under water with with out a mask, mask, you know that it is impossible to see clearly clearly there. Our eyes are designed designed to focus in air. air. A scuba mask places places a layer layer of air air betweenyour eyes and the water, enabling enabling you to see underwater obje objects cts clearly. clearly. A scuba scuba mask differs from swimming goggles in that it it covers your nose. Having Having your nose covere covered enables you to equalize equalize the the pressure inside inside the mask, which increases increases as you dive deeper in the water. The air air pressure pressure inside the mask is equalized with with the water
pressure pressure outside the mask mask when you exhale exhale air air from from your nose nose into the mask. mask. The most important important consideration when when you select select a mask is whether the the mask mask fits your face. To check for fit: 1. Place Place the mask mask gently against your face without putting putting the strap over your head. 2. Inha Inhale le briefly briefly through your nose nose and hold your breath. If the mask sticks against against your face face and does not fall fall off when you look dow down, n, it is a good good fit. If you must must push the mask against your face or continue to inhale to get the mask to to stay on, it is not a well-fi well-fittin tting g mask. (However, this is not true for men with moustaches.) Keep looking looking for a mask that fits. Be sure to to try several different different masks, masks, even even if the first first one you try fits well. well. You might find another style that fits better. You can choose from many different different styles of masks masks.. Some of the features of masks are essential essential and others are optional (figure 2-2). 2-2). Essential features features include: • A tempered glass lens to help resist breaking breaking and avoid injury injury if the lens breaks breaks.. • A solid solid frame to hold the lens in position. • An adjustable, split split or or wide headstrap headstrap that fits fits over a wide portion of of your head.
Dive Mask Double Seal Split
Frame
Nose Pocket
F IGI G U R E 2 -2- 2 . S O M E F EAE A T U R E S O F YO YO U R M A S K A R E E S S E N T I A L .
. L
^ L
NAU I Scuba Sc uba D i ver
e m p i u q E g n i v i D
• The ability ability to block off your nose to help help equalize the pressur pressure e in in your your ears. • Adouble featheredge seal to help help the mask fit fit to your face. There are many optional features you might want to consider consider when when you select your mask. Some popular optional features include: • Side windows windows to provide a wider field field of vision. vision. • Apurge valve to help clear clear water from the mask. • A low-volume mask that that fits fits closely closely to your your face to give give you a wider angle of vision. vision. It is also easier to clear of water. water. • Prescr Prescript iption ion lenses. New New mask lenses are covered covered with with a thin thin film film of lubricant lubricant.. You can use toothpaste to remo move ve this lubri lubri cant by using the following following procedure: procedure: 1. Put Put a litt little le toothpaste on the the inside of each lens of the mask. 2. Rub the toothpaste over the entire entire lens with with your fingers or a soft, wet cloth. 3. Rinse Rinse well with with fresh water. Washing Washing the lens lens with toothpaste helps keep the lens from fogging, fogging, which which occurs when condensation condensation forms on the inside of the lens. lens. Each Each time you don your mask mask for diving, you w will ill need need to to prepare prepare it so that it will will not fog because of the temperature differen difference ce inside inside the the mask compared to the surroundi surrounding ng water. The most common way to prevent fogging used to be to spit in in the mask, rub the saliva saliva on the lens, and then rinse the mask. mask. A better better alternative is to use commercially a ava vail il able anti-fog anti-fog sprays, drops, or creams. creams.
Snorkels Have you you ever noticed that you can lie lie face down down on the surface of the the water and float float completely motionless? It’s easy, and most people can do it. However, every time you need to breathe, breathe, you must lift lift your your head out of the water and that takes exertion exertion and gets tiring. tiring. A snorkel is the answer answer to this problem, problem, (figur (figure e 2-3). 2-3). A snorkel enables you to to breathe normally normally while you watch the beauty beneath you. Even litt little le kids can easily easily enjoy the activity. activity. The snorkel helps you conserve conserve energy energy - and the air air in your scuba scuba cylinder - any time
16
F IGI G U R E 2 - 3 . D I F F E R E N T T Y P E S O F S N O R K E L S .
F IGI G U R E 2 - 4 . A S N O R K E L E N A B L E S Y O U T O B R E A T H E A S Y O U E N J O Y T H E B E A U T Y B E N E A TH Y O U .
you are swimming on the surface (figure (figure 2-4). There are many different features features available available with snorkels. The basic snorkel is a “J ” shaped tube with a mouthpiece at the the curved end (figure (figure 2-5). Other fea tures that can be added added to the the basic snorkel include: • Flexible Flexible hosing to enable the snorkel to fit com fortably in your mouth. • Apurge valve to allow allow water to drain out of the bottom of the tube. • A swivel swivel mouthpiece mouthpiece so you can can adjust adjust the mouthpiece in your mouth and swivel it out of the way when you switch to a regulator. regulator.
Chapter 2- Diving Equipment
F IGI G U R E 2 -6- 6 . B O O T I E S P R O V I D E W A R M T H A N D P R O T E C T I O N F O R Y O U R F E E T W H E N W A L K I N G O V E R R O U G H S U R F A C E S .
The inside diameter of the s snorkel norkel should be no less m than 2 centimeters (3/4 (3/4 inch inch). ). If the diameter is too too small, it is like breathing through through a straw straw.. If the diame ter is too large (over 2.5 2.5 centim centimeters eters or 1in 1inch ch), ), the snorkel is awkward awkward to clear. Also, avoid a snorkel that has any sharp sharp bends or angles.
Booties F IGI G U R E 2 -5- 5 . S N O R K E L S H A V E B O TH TH E S S E N T I A L A N D OPTIONAL FEATURES.
m
• Baffles at the top of the “J ” tube to keep water from getting into the snorkel at the surface. • Amolded or soft mouthpiece mouthpiece for for added comfort. The two most important important things things to consider when selecting your snorkel are comfort and breathing breathing ease. ease. The mouthpiece mouthpiece must fit comfortably in in your your mouth and should not be twisted when you place place the tube or barrel of the snorkel snorkel over your left left ear. The snorkel itsel itselff should be between 30 and 35 centimeters (12 and 14 inches) inches) tall. tall. If your snorkel is too too short, short, it will constantly fill fill with water. water. If your snorkel is too long long,, it wil willl be harder to get a good good breath of fresh fresh air. air.
Booties provide protection and warmth for for your feet. feet. They also serve as shoe shoes s when you you are walk walking ing around a dive boat or dive site. Booties Booties are made from neoprene, which is synthetic synthetic rubber injected injected with a gas, gas, usually nitrogen, to make it spong spongy. y. The tiny gas cells in the rubber provide insulati insulation on for for your feet. The neoprene is usuall usually y covered covered with nylon to make make the bootie comfort able against against your skin skin and easy to put on and take off. The neoprene neoprene can be thin or thick thick for for warm-water or cold-water cold-water diving, diving, respectively. The bootie bootie should also have a sole sole to protect the bottom of your your foot from rocks and rough surfaces (figur (figure e 2-6). 2-6). You wear booties with with heel-strap fins fins and some times with full-foot fins. Some of the different different types of booties booties you can find find are: • Slip-on 3 millim millimete eterr (1/8 inch) inch) booties booties that com come up to your ankle ankle for warm-water warm-water diving.
NAU I Scuba Sc uba D i ver
F in
F I G U R E 2 -8- 8 . I F Y O U A R E W E A R I N G B O O T I E S W I T H Y O U R F I N S , B E S U R E T O T R Y T H E M O N A T T H E S A M E T IM IM E S O Y O U CHOO SE A FIN THAT IS THE RIGHT SIZE. F IGI G U R E 2 - 7 . F I N S C O M E ININ B O T H F U L L F O O T A N D H E E L STRAP STYLES.
• Booties with zippers that come up up over your ankle. ankle. The zipper should have a backi backing ng to prevent water from entering dire directly ctly through the zipper and to keep the zipper from rubbing rubbing your skin. skin. The bootie bootie should fit snugly but comfort comfortably ably on your foot. foot. If it it is too too large for your foot foot,, you will ill have a lot of water transfer in and out of your bootie during a dive and your foot will ill get cold. The excess room might might also preven preventt your fin from fitting fitting properly or make it loose enough to come off.
Fins Fins provide your means of propulsion or way to move yourself yourself through the water. Once Once you have all all your scuba gear gear on, on, it it is diff difficu icult lt and awkward to use your hands and arms to move through through the water. With With fins, you can can use the larger larger muscles muscles in in your legs legs for swimming and have your hands free for other other uses. fin s and There are two basic types of fins: fins: full-foo t fin heel-s heel-strap trapfin s (figure 2-7). Full-foot fins are typically typically used used for snorkeling and in warm water. Your entire foot
is enclosed in the foo t pocket of of the fin. Heel-stra Heel-strap p fins fins also have a foot pocket, but the back of the pocket is open and an adjus adjustabl table e strap goes across the opening. You must wear booties with with heel-strap fins fins to protect your feet from blisters. blisters. You can use heel-strap fins for diving in any temperatu temperature re water. water. Fins Fins come in a range of sizes from small small to extralarge. large. The size of the fin determines the size of the footpocket and the blade length and width. The blade of the the fin fin is the flat flat portion portion that extends extends away from the foot pocket. You must must choose oose a fin that fits snugly snugly to your foot without cramping your toes toes or pinching your feet (figure (figure 2-8). If your fin is too too large, it will will be too too hard hard to kick, can can cause cramps, cramps, and can easil easily y be be lost. lost. You must pick the fin that that is right right for you and your level of physical conditioning conditioning.. You must be able to kick comfortably comfortably with your fins for long period periods. s. Fins that are too large and stiff stiff for your your leg muscles can cause your legs legs to cramp and will ill not be comfortable. comfortable. You might be more mor e comfortable with a shorter, shorter, more flexible fin. Fins come in many different different materials materials and styles styles depending depending on the manufacturer. The fin must with with stand exposure to sun, salt salt,, and sand, so you should purchase a good good qualit quality y fin that can withstand withstand hard use. use. Some fins come with a plastic insert in each foot foot
C h a p t e r 2 18234876 “ ' / .
F IGI G U R E 2 -9-9 . G L O V E S P R O T E C T YO YO U R H A N D S F R O M C O T S A N D A B R A S I O N S A N D K E E P YO Y O U R H A N D S W A R M I N C O LDL D W A T E R .
pocket pocket.. The insert helps helps maint maintain ain the shap shape e of the foot pocket when your foot is not in the pocket. You should keep the inserts in the foot pockets pockets whenever you store your fins.
Gloves Gloves Gloves are considered considered basic gear in in many parts of the world. Gloves protect your hands from cuts and scrapes and and provide provide warmth in cold water (figure (figure 2-9). You wear gloves gloves in warm water to protect your hands from injury. injury. They can be made made out of cotton, a thin nylon material material,, or thin neoprene neoprene,, some with a leather or simulated-leather palm. You wear gloves or mitts in in cold cold water to keep your hands hands warm and to protect your hands from the envi envi ronment. Cold-water gloves are made from neoprene. neoprene. Your gloves gloves should fit fit snugly and allow allow you to move your fingers fingers easily. easily. You must be able to handle your equipment equipment while while wearing gloves gloves. Your instructor instructor might have you wear gloves gloves during your your confined confined water traini training ng so you learn learn how to work while wearing wearing gloves. gloves. You should not touch or handle handle the creatures you find under water just because because your gloves gloves are protecting you from the environment. In many case cases, s, you can hurt or kil killl plants or animals animals just by touching tthe hem. m. Coral reefs reefs are parti particu cular larly ly sensitive to touch and many corals are easily broken. Many fish are cove covered red with a protective slime, and removing the slime makes the fish subject to to infection infection or parasites. parasites.
F IGI G U R E 2 - 1 0 . Y O U S H O U L D R I N S E Y O U R E Q U I P M E N T W I T H F R ESE S H WATER AFTER EVERY DIVING DAY.
Me In som some areas of the world, you are no longer allowed to wear gloves gloveswhen diving diving (for (for example: example: Cozumel, Cozumel, Mexico). This is to ensure that you will ill not touch the reef and harm delicate corals corals to die. die.
Flotation Device Divers should wear some type of personal flotat flotation ion device for snorkeling snorkeling and skin diving. diving. The most com monly used used piece piece of flotation equipment is an inflatable inflatable vest that is is worn on the chest chest and is usuall usually y referred to as a skin diving diving or snorkeling snorkeling vest vest.. The vest is design designed to slip over your head and fasten at your waist with a strap. Most vests of this design design also have some type of oral inflation tube.
Maintenance Maintai Maintaining ning your basic skin diving gear, gear, as well as
NAU I Scuba Sc uba D i ver
your scuba gear, gear, is simple. You should rinse your gear with fresh water after every diving diving day (figure (figure 2-10 2-10). ). Be sure that you do not leave your gear in the sun any more mo re than necessary necessary becau because se sunligh sunlightt and heat are V extremely extremely damaging to scuba gear gear and neopren neoprene, e, ail
At the end of a diving trip, soakyour gear gear overnight in fresh water and then rinse it thoroughly thoroughly with fresh water. Make sure the gear is dry before before you store it in a cool, dry area, like a closet. For extra protection, you can store your dry gear in a sealed, sealed, plastic plastic bag. No matter howwell you maint maintain ain your your gear, you will ill need need to replace some parts periodically periodically.. Fin Fin straps, straps, mask straps, and snorkel keeperswear out. You must
CYLINDERS When most people think of scuba diving, diving, they immediately think think of the cylinders that divers wear wear on their their backs. backs. Scuba cylinders a allo llow w you to store store large amounts amounts of air in a small space. space. Scuba cylinders ar are e also known as bottles or tanks. Every Every country country can can be expected to have standards regulating scuba scuba cylinders. In the United States States,, cylin cylin ders ders are regulated by the Department of Transportation (DOT) (DOT) and must be pressure tested tested accordi according ng to govern ment standards. standards. In Canada, cylinders cylinders are regulated by the Canadian Transport Commis Commission sion (CTC) (CTC),, which which has standards simila similarr to the United States Departmen Departmentt of Transportation.
inspect your gear regularly regularly,, and especially especially before before a dive trip, trip, to give you a chance chance to replace worn parts before they break.
V e r i l y W t i a t Y o u H a v e L e a r n e d Review the following following questions questions on basic equipment: equipment: 1. The two most important important features features for the selection of your mask, mask, snorkel, booties, booties, and fins fins are: □ Com Comfort fort
□ Style Style
□ Fit
□ Color olor
□ Price Price
□ Materi Material al
2. One feature that that is not essential essential in a dive mask is: a. Purge valve b. Tempered glass c. Nose-blocking device d. Rigid frame 3. List two factors that that can can reduce the ease ease or efficiency of breathing through a snorkel:
Characteristics The air air in in a scuba cylinder cylinder is high highly ly compressed, so a cylind cylinder er must have strong walls walls to withstand the pressure. The pressure of cylinde cylinders rs ranges from 120 bar (1800 pounds per square inch [ps [psi]) i]) to 310bar (4500 psi). psi). One One bar is equal to approximately 14.7 psi or 1 atmosphere sphere (atm (atm). ). Mo Most st cylinders cylinders are made made of aluminum or steel.
A l u m i n u m Aluminum Aluminum cylinders cylinders do not rust, rust, which which is an advantage over steel steel cylinders. However, ever, aluminum aluminum cylinders cylinders are more easily damaged damaged than steel steel cylinders cylinders on the outside and the threads threads where where the cylinder cylinder valve screws in must be inspected regular regularly ly for cracks and other problems. If water enters nters an aluminum aluminum cylinder, the cylinder corrodes and forms alumin aluminum um oxide. Once aluminu aluminum m oxide has formed, it it slows further further corrosion corrosion to the cylinder. cylinder.
Steel Steel cylinders cylinders are more resistant to exterior damage. damage. However, ever, if if water enters enters a steel steel cylinder, cylinder, the cylinder cylinder corrod corrodes es and form forms s rust that can quickly quickly ruin ruin a steel steel cylinder. cylinder. If you suspect suspect that water has entered
m
Chapter 2- Diving Equipment
U.S. Markings
European Marking Marking s 2
Steel Cylinder(3AA=Steel) 1. Regulatory Agency 2. Type 3. Working Pressure(Bar) 4. Manufacturer 5. Test Date 6. Serial Number
1. Gas Ty p e
8. Ser i al N u m b er
2. Ow n e r
9. St an d ar d
3. S c ub ub a E qu qu i pm pm en en t
10. T es es t P re re ss ss u re re
4. S er er v ic ic e Pr es es s ur ur e
11. E WG WG T ra ra de de ma ma rk rk
5. EWG EWG Design Design Permit Permit
12. 12. RepeatTest RepeatTest
6. Co u n t r y o f
13. Em p t y W ei g h t
Man u f a c t u r e r
Al um in um Cy li nd er (3AL=A (3AL=Aiuminum iuminum)) 1. Regulatory Agency 2. Type 3. Working Pressure 4. Serial Number 5. Manufacturer 6. Size 7. Test Date
14. Mi Mi n i m u m Vo l u m e
7. Manufactur er Symbo l 15. Galvanized
F IGI G U R E 2 1 1 . C Y L I N D E R M A R K I N G S P R O V I D E I M P O R T A N T INI N F O R M A T I O N A B O U T T H E C Y L I N D E R .
the cylinder, cylinder, an inter internal nal inspection inspection should be made made at a qualified facility.
Sizes Scuba cylinders come in many different sizes. In the metric metric system, the size of the c cyli ylinde nderr is is expressed as the volume the cylinder cylinder actua actually lly holds. In the United States, the size of the cylind cylinder er is is expressed as the volume of com compresse pressed d air the cylinder cylinder wil willl hold. Some metric metric sizes you may see when diving diving include: • A 12-lit 12-liter er cylinder made out of aluminum aluminum rated rated for a pressure of 200bar. • A 10-lit 10-liter er cylinder made out of aluminum aluminum rated for a pressure of 200bar. • A 10-liter cylinde cylinderr made out of steel rated for for a pressure of of 150bar. • An 18-liter cylin cylinder der made out of steel steel rated rated for a pressure pressure of 160bar. bar.
Some United States sizes you may see when divin diving g include: • An 80cubic foot cylinder cylinder made out of aluminum aluminum rated for for a pressure of 3000 3000psi. • A 63 cubic foot cylinder cylinder made out of alumin aluminum um rated for for a pressure pressure of 3000 psi. • A 72 cubic cubic foot cyli cylind nder er made out of steel rated for a pressure of 2475psi. • A 95 cubic foot cylinder cylinder made out of steel steel rated for a pressure of 2640psi.
Markings Markings are placed on the the shoulder of each cylin cylin der to provide important important pieces pieces of informatio information n about the cylinder cylinder (figure (figure 2-11). 2-11). The markings include: include: • The serial number of the the cylinder, which is unique for each cylinder cylinder made by a single manufacturer. • The The name of the the manufactur manufacturer er or their their symbol. • Government-required marks to signify signify that that the
NAUI Scuba Diver
Cylinders can can also also be be covered covered with with a rubber or or plastic plastic net. The net protects protects the the exterior of the cylinder cylinder and its paint. You might also see see divers with two cylinders hooked together together with a manifold manifold sharing sharing a common valve.
i e m p i u q E
V a l v e s Every cylinder cylinder must have have a valve to hold the air in the cylinder cylinder when it is not in use, use, to control the flow of of air air out of the cylinder, cylinder, and to provide an attachment point for the scuba regulator. A valve valve acts like like a water water faucet. You open open the the valve by turnin turning g a handle (knob) (knob) counterclockwise and close close the valve by turning turning the knob clockwise, as seen from from the top of the valve handle.
g n i v i D
F IGI G U R E 2 1 2 . T
V A LVL V ES E S A R E T H E M O S T C O M M O N T Y P E O F V A LVL V E
F O U N D I N T H E U N I T E D S T A T ES ES .
cylinder cylinder was manufactured anufactured according to its standards. • The service pressu pressure of the cylinder, cylinder, which which is the pressu pressure to which the cylinder can be filled filled (for example, 200 bar or 3000 psi) psi).. • A “+” “ +” mark on steel steel tanks, tanks, authoriz authorizing ing a 10 percent pressure over overfi fillll beyond the stamped service pressure. • The materia materiall of which which the cylinder cylinder is composed (for examp example, le, 3AL 3AL stand stands for a parti particula cularr alu alu minum alloy). • The The hydrostatic testing date of the cylind cylinder er (fo (forr example, example, 8/97 8/97signifies signifies that the cylin cylinder der was test ed in August of 1997 1997). ). In the United States, hydrostatic hydrostatic testing must be performed every five years. years. In Japan, Japan, hydrostatic testing must must be performed every three years. In Australia, Australia, hydrostatic hydrostatic testing must be done every year.
A c c e s s o r i e s Cylinders Cylinders sometimes have boots on the bottom to protect the the bottom bottom of the cylinder cylinder and its environment. Some steel cylinder cylinders s have a rounded bottom and need a boot to be able to tempora temporaril rily y stand upright. upright. You must remove the boot boot on a cylinder cylinder periodi periodical cally ly to properly rinse the bottom of the cylinder. cylinder.
22
T
V a lv e s
The United States States “K” “ K” valve is one one valve you will see often when diving diving (figur (figure e 2-12). It is design designed like like a post post with an on/off knob. The first stage regulator regulator yoke fits over the post and the regulator is tightened against the post with with a screw. screw. These These valves are not usuall usually y used at pressures higher higher than than 200 bar (3000 psi) psi).. An O-ring O-ring or gasket gasket found on the cylinder cylinder valve makes a seal between the regula regulator tor and valve. valve. If the Oring is damaged or missing, the regulator wil willl not seal to the cylinder cylinder and air air will will escape. You should replace O-rings frequently frequently because of wear.
" J " V a lvlv es es A “J ” valve look looks s like the “K” “K” valve with a lever lever opposite the on/off knob. This lever lever is known as a reserve reserve mechanism. mechan ism. The mechanism is designed to begin to restrict ai airfl rflow ow at about 20 bar (300 psi) to 33 bar (500 psi) of pressure pressure in the cylinder. cylinder. When the mechanism is manu manual ally ly opened, the airflow airflow is no longer restricted. submersiblee pres “J ” valves were popular befo before re submersibl sure gauges gauges (SPG (SPGs) s) were commonly used. The reser reserve ve mechanism had to be placed placed in in the up position at the start start of the dive. The lever lever was moved to a down posi tion by means means of a cord or rod when the diver noticed
m
Ch apter 2- Diving Diving Equipm Equipm ent
F IGI G U R E 2 - 1 3 . D IIII U V A L V E S O R I G INI N A T E D I N E U R O P E A N D A R E CAPABLE OF OPERATING AT PRESSURES GREATER THAN 200 BAR (3000 PSI).
diffi difficul culty ty breathing. These These levers levers were easily easily bum bumped ped out of the the up position during during the dive and the diver would be using the last air air without without knowing it. You will see “J” “J ” valves in use, use, but the valve is always used with the reserve reserve lever in in the down position. The mechanism mechanism is rar rarely ely usedbecause divers now use use sub mersible pressu pressure re gauges gauges to monitor their their air air supply.
disk. This relief relief mechanism is necessary to to keep the cylinder cylinder from rupturing rupturing if if the cylinder beco becom mes extremely hot, or otherwise oveipressurized.
D I N V a lvl v e s
Maintenance
The DIN valve system system originated originated in Europe. The DIN valve valve has a large, threaded opening and the regula tor screw screws into the valve (figur (figure e 2-13). This system is capture d O-ring system. system. While also known as the captured common in the rest of the world, DIN DIN valves are not commonly seen in the United States. States. The DIN valve is is stronger stronger and capable of operating at pressure pressures s higher higher than than 200 bar (3000 psi). psi).
Proper care of your cylinder cylinder includes rinsing rinsing the outside outside with fresh water after using the cylinder, having the cylinder visua visually lly inspecte inspected each year, and having the cylind cylinder er hydrosta hydrostatica tically lly tested tested as required by governm government ent standards.
Burst Bisks □
pressuree Every cylinder valve valve is equipped ipped with a pressur relief disk or or burst disk. This disk is designed to allow the cylinder cylinder to vent excessiv excessive e pressure by bursting bursting the
F IGI G U R E 2 - 1 4 . Y O U R S C U B A C Y L I N D E R M U S T B E V ISI S U A L L Y INI N S P E C T E D A T L E A S T O N C E P E R Y E A R .
Scuba cylinders must be inspe inspected cted internal internally ly and externally externally at least once per per year at a professional professional dive shop shop or a dive-equipm dive-equipment repair facil facility ity by a certified cylind cylinder er inspector. inspector. The cylinder cylinder is inspected for dents, nts, marring, marring, and fire or heat discoloration discoloration on the ou outsid tside e and for corrosion, water, and cracks inside (figure (figure 2-14)
NA UI Scuba Sc uba D i ver
F I G U R E 2 -1- 1 6 . H Y D R O S T A T I C T E S T I N G S T A R T S B Y F ILI L L INI N G T H E S C U R A C Y L I N D E R W I T H W A T E R A N D P L A C I N G I T ININ A L A R G E R C Y L I N D E R D F W A T ER ER .
vgen Servlc* L .7.—
fOUCAllON
decrease back within within set set limits limits when the pressu pressure is relieved, the cylinder cylinder can can no longer be used. sed.
F IGI G U R E 2 1 5 A V ISIS U A L C Y L I N D E R I N S P E C T I O N S T I C K E R ISI S P L A C E D O N Y O U R C Y L INI N D E R W H E N I T H A S P A S S ED ED ITS VISUAL INSPECTION.
If the cylinder passes sses the visual visual inspection, inspection, a visual visual cylinder cylinder inspection sticker is attached to the cylinder with the month month and year of the inspection noted on the sticker (fig (figure ure 2-15). If the cylinder cylinder does not pass the the visual visual inspection, it it might need to be cleaned or tum bled to remove oxidation. If the cylind cylinder er needs needs to to be tumbled, tumbled, it autom automatic aticall ally y needs eds hydrostatic testin testing. g.
Hydrostatic Testing a m
In the United States, States, hydrostatic testing is required every five years or whenever the cylinder cylinder must be cleaned by by tumbling. tumbling. Hydrostatic testing test tests s the cyli cylin n der for metal fatigue. During During hydrostatic testing, the scuba scuba cylinder is filled filled with water and placed placed in a larger sealed cylinder cylinder full full of water (figu (figure re 2-16). The pressure of the water in in the scuba scuba cylinder cylinder is increased to 5/3 the the service pressure of the cylind cylinder er and then then reduced to the pressure of the surrounding surrounding water. water. If the cylind cylinder’s er’s size size increases with with the increase increase of of pressure but does not
Storage You should store store cylinders for any long term with some pressure in the cylinder. cylinder. In steel steel tanks, keeping keeping som some air air in your cylinder cylinder ensures ensures that water cannot enter your cylinder and cause cause corrosion. corrosion. With alu alu minum tanks, this is not as much of a concern. Aluminum Aluminum tanks can can be stored stored empty empty and with the valves open open so that they will will not be a hazard in a fire. You should store store cylinders cylinders upright upright in a cool, dry, and protected locat location ion where they cannot be knocked knocked over. over. Never leave a cylinder cylinder standing standing by itself itself when when you are not holding it. You should should lay lay your cylinder down to prevent damage damage to it, the valve valve,, or inju injury ry to someone. When transporting a cylinder in a moving moving vehicle, place the cylinder cylinder on its side and secure it to prevent damage to the cylinder, cylinder, the valve, or the vehicle. vehicle.
Backpacks Backpacks are designed designed to hold a cylin cylinder der securely securely on a diver’s diver’s back. Backpacks are now usuall usually y incorpo rated directly directly in in the buoyancy compensator, compensator, but you might sti stillll see divers using a backpack and separate separate buoyancy control control device. The backpack must be used used
Chapter 2- Diving Equipment
with an easily easily adjustable harness with a quick-release quick-release buckle at the waist and at least least one at the shoulder. shoulder.
V e r i f y W h a t l a H a v e L e a r n e d i v i n g
Review the followin following g questions questions about cylinders: 4. What is the difference between a “J” “J ” valve valve and a “K” valve?
E q u i p m e n t
5. The two types of metal metal used to make scuba scuba cylinders are and _____________________
6. In the United States, States, a visual visual inspection inspection is per formed and_a_hydro static test is performed performed . ____________________
________________
F IGI G U R E 2 1 7 . Y O U R S C U B A R E G U L A T O R D E LIL I V E R S A IRIR T O YO YO U O N D E M A N D A N D P R O V IDI D E S E A S Y B R E A TH T H INI N G UNDERWATER.
REGULATORS The scuba regulator is is a mechanical device that delivers air to you on demand demand (figur (figure e 2-17). One func tion of the regulator regulator is to reduce the high pressure of the the am bientt pressur pressure, e, or the pres air in the cylinder to the ambien sure surrounding your body, body, so you can breathe it. Regulators Regulators are composed of two main parts: the first first stage and the second stage. Regulator Regulators s also commonly have other pieces of equipment attached attached to them, includin including g addition additional al regulator regulator second stag stages and and gauges. F IGI G U R E 2 1 8 . T H E F I R S T S T A G E O F T H E R E G U L A T O R A T T A C H E S
First Stage The first first stage of most United United States type regulators fits over the pos postt of the cylinder valve using using a device com com bining bining the yoke yoke and yoke screw (figure (figure 2-18). Some use a DIN threaded threaded fitting. fitting. In the first first stage, the high-p high-pres res sure air from the cylinder is reduced to approximately 10bar (150 psi) above the pressure pressure surroundi surrounding ng the cylinder. The air from the the first stage stage is then delivered to the second stage through through a low-pressure hose. The first stage stage of your regulator regulator has a number of
D I R EC E C T L Y T O T H E S C U B A C Y L INI N D E R .
outlets or ports to which which hose hoses s and pieces of equipment are attached. The first first stage must have at least one high-pressure port. This This port bypasses the mechanisms that reduce the pressure from the cylinder cylinder.. Your sub mersible mersible pressure gauge gauge is attached attached to this this port so you m can monitor your ai airr supply. supply. The following following hoses oses might
NAU I Scuba S cuba D i ver
i e m p i u q E g n i v i D
F I G U R E 2 - 1 9 . T H E M O U T H P I E C E IS A T T A C H E D T O T H E S E C O N D STAGE OF THE REGULATOR.
F IGI G U R E 2 -2- 2 0 . T H E M O S T C O M M O N A L T E R N A T E A IRI R S O U R C E ISI S A N OCTOPUS REGULATOR.
be connected to low-pressure ports in additio addition n to your prima primary ry second stage stage hose: • Apower-inflator power-inflator hose for your buoyancy buoyancy compensator. • An alterna alternate te second stage or octopus regulator. regulator. • A dry suit suit power-infl power-inflator ator hose, if if used.
Second Stage The second stage tage of your regulator regulator has a mouth piece attached to to it (fig (figur ure e 2-19). The second stage fur fur ther reduces the air air pressure from approxi approximately mately 10 bar (150 psi) psi) above the surround surrounding ing pressure to whatever the ambient pressure pressure is. Therefore, the air air you breathe is always always at the pressure needed needed by your body, no matter how deep you are are under the water. Some Some regulators offer higher performance than than others others and deliver deliver a greater volume of air air at deeper per depths regardless regardless of flow restrictions. This is important, important, because the deeper you go, the denser the air. air. If you plan plan to leam leam to do deep, wreck, wreck, cave, or ice divin diving g or do underwater hunting, hunting, you will will want want a high-perform high-performance ance regulator.
A l t e r n a t e A i r S o u r c e s It is standard practice that that you and your buddy be
26
FIGURE 2-21. SOM E ALTERNATE AIR SOURCES ARE COM BINED WITH THE P O W E R I N F LAL A T O R O F T H E B U O Y A N C Y C O M P E N S A T O R .
equipped equipped with alternate alternate air air sources sources in case of emer gency. An alternate alternate second stage can be attached to your primary primary regulator, or you can carry a source source of air totally separate from your scuba cylinder.
O c t o p u s R e g u l a tot o r s The most most common alternate alternate air air source is an an octo pus pu s regulato regulator r (figur (figure e 2-20 2-20). The octopus regulator regulator is an additi additional onal second stage stage that allows allows you to share air from your cylinder cylinder with another another diver. diver. The hos hose e for the
Ch apter 2- Diving n g Equipm Equipm ent
F IGI G U R E 2 2 3 . T H I S ISI S A N O T H E R T Y P E O F C O N T I N G E N C Y S C U B A .
F IGI G U R E 2 - 2 2 . S M A L L S C U B A C Y L INI N D E R S W I T H T H E IRIR O W N REGOLATOR ARE CALLED PONY BOTTLES.
octopus regulator regulator should should be at least 10 centimeters centimeters (4 inches) inches) longer than a standard regulator hose. hose. The octopus pus regulator regulator is is inexpensive, convenient, and easy to use. However, it it is not a source of air air separate from your scuba cylinder, cylinder, so your remain remaining ing air air supply is depleted depleted much faster when when it it is is in emergency emergency use use by another diver and yourself. Another type type of alternate alternate air air source is a combina combina tion regulator and power-inflator for your buoyancy compensato compensatorr that fits on its power-inflator power-inflator hose hose (figur (figure e 2-21 2-21). These These units elimi eliminat nate e the extra hose for an octopus regulator and are easy to locate in in case of an emergen emergency. The air donor typic typicall ally y uses this alternate alternate air air source and gives their prima primary ry air air source to the the other diver.
Contingency Scuba Contingency Contingency scuba scu ba or true alternate air air sources rces provide a totally totally independent independent regulator regulator and air air supply. supply. The two main main types of contingency scuba are: pon y bottl bottle, e, which is a small scuba cylinder •A pony with a separate separate regulator regulator (figur (figure e 2-22 2-22). Pony bottles are commonly commonly used by wreck divers and divers divers who dive deep.
• Asmaller cylinder cylinder with an integrated first and second second stage stage mounted directly directly on the cylind cylinder er (figure 2-23). Contingency scuba provides provides an excellent excellent backup for yourself yourself if if you and your your buddy buddy getseparated under under water. Howeve However, r, contingency contingency scuba adds adds additiona additionall expense to your scuba equipment as well as extra bulk and weight.
P o s i tit i o n o l t h e A l t e r n a t e M o u t h p i e c e The mouthpiece mouthpiece for your alternate air source source should be located on the front of your body (figu (figure re 224). The mouthpiec mouthpiece e for your alternate air air source source must must bevisible, easy to identify, and available available for immediate usewhen it is neede needed. An alternate alternate air air source will ill not do you or your buddy any good if it cannot be located immediately during an emergency.
Gauges Divers must rely on gauges gauges and instruments to tell them depth, epth, bottom bottom time, direction, direction, and air air supply, just as a pilot relies on instrumentation to fly a plane. The gauges gauges and instruments can be integrated into a console or worn separately. console streamlines your gauges into one Adive console unit. unit. The console is an enclosure molded with with slots to hold hold a submersible pressure gauge, depth gauge, gauge, and sometimes a compass.
NAU I Scuba Diver
mares B R A S S
F IGI G U R E 2 2 5 . T H E S U B M E R S I B L E P R E S S U R E G A U G E I S A R EQ E Q U IRI R E D P I EC EC E O F S C U B A E Q U I P M E N T .
F IGI G U R E 2 2 4 . Y O U R A L T E R N A T E A I R S O U R C E M O U T H P I EC EC E S H O U L D B E LO LO C A T E D O N T H E F R O N T O F Y O U R BODY AND BE CLEARLY VISIBLE.
psi) psi) when when the pressure pressure is reduced reduced to half, half, and soon. SPGs are sensitive instruments and you should should not subject them to shocks or abuse. If you notice a small leak leak from the hose or connecti connection on between the hose and and SPG, it is is not necessary necessary to end end your dive immediately. However, you should have the SPG SPG and hose serviced as soon aspossible to your NAUI Pro Pro Center or dive-equipment repair facilit facility. y. If you see water in your SPG, have it serv serv iced as soon soon as possible and do do not rely on it for diving diving until you do. SPGs can can also be integrated in dive dive computers and measure measure pressure electronic electronically. ally. In addition, someairintegrated dive computers can also monitor your breathing rate and predict how long the air in in your cylin cylin der will ill last based onyour breathing breathing rate (figure (figure 2-27).
S u b m e r s ibib lel e P r e s s u r e G a u g e submersible blepressure pressure gauge (SPG) The submersi (SPG) is a required piece of equipment equipment for scuba diving. The SPG displays displays the amount of air pressu pressure re remaining remaining in your scuba cylinder cylinder in in the same way a fuel fuel gauge gauge shows ows how much gas gas you have have left in your ca car’s r’s gas tank. By look ing at your SPG frequently during your dive, you you will will know when your air air supply is getting low and it is time to end end your dive before before you run out of air. air. All mechanica mechanicall SPGs perform the function of measur ing the air pressure in your scuba cylind cylinder er (fig (figure ure 2-25). SPGs give a reading reading in bar or pounds per square inch inch (psi). (psi). For a typical alum aluminum inum cylinder, the SPG reads 200 bar (300 (3000 psi) psi) when the cylinder cylinder is full, full, 100bar (1500
Depth Gauge Your depth and th the e duration duration of of your dive at at any particu particular lar depth depth are limited by a number number of factors, so so you need to monitor your your depth when diving. diving. A depth depth gauge gives you a way to measure your your depth when you are under water (fig (figure ure 2-28). There are four types of depth gauges: • Capillar Capillary y tube • Bourdon Bourdon tube tube • Diaphragm mechanism • Electr Electroni onic c gauge The capilla capillary ry tube is a simple, simple, inexpensive inexpensive instru ment that consists of a clear clear piece of tubing sealed at
Chapter 2- Diving Equipment
05332874
iBS/lS
F IGI G U R E 2 2 6 . T H E S P G ' S I N T E R N A L M E C H A N I S M . F IGI G U R E 2 2 8 . A D E P T H G A U G E M E A S U R E S Y O U R D E P T H W H E N Y O U A R E U N D E R W A T E R .
F IGI G U R E 2 -2- 2 7 . M O S T E L EC E C T R O N I C S U B M E R S I B LEL E P R E S S U R E G A U G E S A R E I N T E G R A T E O W I T H O IVI V E C O M P U T E R S .
one end. The tubing is marked with numbers numbers that correspond to your depth. As you descend in the water, water enters the tube and compresses the air air inside. inside. You read your depth depth by by looking looking at the air air and water interface interface inside the tube. tube. A capi capilla llary ry tube is very useful at shallow shallow depths (above (above 12 meter’s or 40feet), feet), but is not recom recom mended for for deeper depths, as the scal scale e size becomes too small for accurate readings. A Bourdon tube uses pressure to straigh straighten ten a curved metal tube. Bourdon Bourdon tubes can be open or closed, although although open tubes are rarely rarely seen today. The closed tube is filled with with air air and is enca encased sed in a housing fil filled led with oil. oil. The pressure from the surrounding surrounding water is
transmitted throug through h a flexible part part of the housing to the oil and then to to the tube. tube. The tube is attached attached to a linkag linkage e and and needle and as the pressure opens opens the tube, tube, the needle moves moves to show your your depth. Bourdon Bourdon tubes measure depth reasonably accurately. A diaphragm mechanism uses a metal diaphragm, which is attached attached to to a linkage. The linkage is attached attached to a needle. As the pressure pressure increases on the diaphragm, diaphragm, the needle moves to show your your depth. Diaphrag Diaphragm m gauges gauges can often be adjusted adjusted for thei theirr zero point. Electronic Electronic depth gaug gauges es are part of all all dive comput comput ers and most electroni electronic c dive timers. An electroni electronic c depth gauge measures your depth using using transducers, transducers, and then displays the depth depth digita digitally lly.. Electr Electroni onic c depth gauges are extremely extremely accurate and reli reliable. able. You must have a means of record recording ing the deepest deepest depth you reach on a dive. Capil Capillar lary y gauges do not have a means of recording recording your your deepest depth so you must remember to record record it on a slate during during your dive. Bourdon tube and diaphragm diaphragm gauges might have a sec ond needle that is pushed around the gauge by the depth needle attached to the linkage linkage.. The second needle stays at your your deepest depth while while the depth needle keeps show ing your current current depth depth. Electr Electroni onic c depth depth gaug gauges record record your maximum maximum depth depth in their their memory and then display the maximum maximum depth when you surface surface or on demand.
NA UI Scuba Diver Di ver
Compass When you you are swimming under under water and visib visibilit ility y is poor, a compass is an important important reference inst instrument, rument, if not essential. essential. Some divers use a compass on every dive, including wh when en diving in clear, clear, tropical tropical water. water. A compass pass can also be crit critic ical al on the surface iiff it is foggy and you cannot cannot see the beach or boat. A compass consists of a magnetized magnetized needle that that aligns itself with the the earth’s magnetic magnetic field. The need needle will ill point point towards magnetic magnetic north north as long as there are no magnetic magnetic influences influences nearby that can can cause the nee nee dle to deviate or turn away from its specified direction. This constant reference to magnetic north north enables you to know know your position or direction of travel under or above the water water relati relative ve to the north-seeking needle. A diving diving compass must: • Be fille filled d with liq liquid uid to withstand pressure and dampen needle movement under water. • Have Have a reference reference line, called called a lubber line, line, used used as the direction direction of travel. • Have a means, such as a ro rotat tating ing bezel, to show a select selected ed bearing or direction (figure 2 -2 9 ).
Maintenance Your regulator, alternate alternate air air source, and gauges are are your life-support system under water water and should should be carefully carefully maintained. Maintenance of your regulator first first and second stages, alternate alternate air air source, and gauges can be divided divided into into steps you can take as a user to keep your regulator regulator in top condition, condition, and step steps that must be perform performed by by a qualified qualified repair technician. You should replace the dust dust cap that fits over the inlet inlet to the first stage whenever your regulato regulatorr is off a cylinder. cylinder. The dust dust cap must be dry before before you fit it over the inlet inlet to the the first stage. The first stage stage contains preci preci sion moving parts and O-rings O-rings.. If water, sand, or dust dust get into the first first stage, they can damage the moving parts, affecting affecting the performance of your regulato regulatorr and making making it diffic difficult ult for for you to breathe. Some dust caps caps use an O-ring to create a seal with the first stage. If the dust cap requires an O-ring O-ring and it is missing, you wil willl see an empty groove in the cap. Be sure to replace replace the
F IGI G U R E 2 2 9 . D IVI V INI N G C O M P A S S E S A R E F I LLL L E D W I T H L IQIQ U I D TO TO W I TH T H S T A N D P R E S S U R E , A N D S H O U L D H A V E A LUL U B B E R L INI N E A N D R O T A T INI N G B E Z E L
O-ring to ensure ensure that you are s sealing ealing the inlet inlet closed. closed. At the end of each each diving diving day, you should rinse your your regulator regulator with with fresh water to remove remove salt crystals or other impurities impurities (figur (figure e 2-30). Always be sure to let water run through the mouthpiece and exhaust tees on the second stage. However, you should should never press press the purge button when running running water through the mouth piece. This could cause water to enter the the hose hose to the first first stage and get get into the first stage of tthe he regulator regulator from there. You should soakyour regulator (if it does not have have a DIN connector), connector), alternate air air source, source, and gauges ges overnight overnight in fresh water at the end of a dive trip, and then rinse them thoroughly. thoroughly. Let the the regulator dry com pletely and then then store it in a cool, dry place. Do not coil the hose hoses tightly tightly or allo allow w them to hang at an angle with weight on them, which which causes kinks kinks at at the hose ends. Hoses that have have been stressed can spring spring leaks leaks and must be replaced. replaced. At least once once per year, year, you should have your regula regula tor service serviced d by a certified repair repair technician. technician. Repair tech nicians nicians are trained by the manufacturers manufacturers in the proper proper metho methods ds to service their their regulators and also to spot spot prob prob lems and correct them them.. The repair technici technician an will will take the first and second second stages apart, clean clean all the metal parts, and replace the O-rings O-rings and other nylon or sili sili cone cone parts of the regulator. The repair technician technician will will
Ch apter 2- Diving Diving Equipm Equipm ent
also test and adjust the intermediate intermediate pressure pressure of your first stage during the service. During During an annual annual service, the repair technicia technician n wil willl also inspect inspect your submers submersible ible pressure gauge and high-pressure igh-pressure hose, depth gauge, and compass for proper operation. operation. Do not leave your gauges ges sitting sitting in the sun. The sun can cause the o oilil in a compass or depth gauge to expand and leak. leak. Also, Also, if you will will be traveling at high altitudes, altitudes, be sure to transport transport your gauges in a pressureproof contai container ner when at more than than 300 meters (1,000 (1,000 feet) above sea level. level.
V e r i l y W h a t t b a H a v e L e s m e d Review the followin following g questions questions about regulators, alternate air air sources, sources, and and instrumentation: instrumentation: 7. The most important important crite criteri ria a when selecting a regulator is _____________________
8. You must must replace th the before before you rinse your regulator. regulator. 9. What is is an advantage to using an octopus regulator? _______
10. What is the primar primary y advantage for using contin contin gency gency scuba instead of an octopus regulator? regulator? 11. A depth gauge is usable usable only at shallow shallow depths. 12. Th The measures measures the air air pressure in your your cylinder. cylinder. _________________
_______________________________
A D D I T I O N A L D I V I N G I N S T R U M E N T S Some additional additional diving diving instruments that you might want to consider consider using include a timing timing device, a com puter, and backup backup instrumentation. instrumentation.
Timing Devices Along with keeping keeping track track of your your depth under water, you must also keep track track of the time you stay stay under water. You can keep track track of your time under
F IGI G U R E 2 - 3 0 . Y O U S H O U L D R I N S E YO YO U R R E G U L A T O R A T T H E EN D OF EACH DIVING DAY.
water by using a watch, watch, an underwater timer, or a dive computer (figure 2-31). Watches usedfor diving diving must be designed to with stand pressure. pressure. They should should be rated for depths of at least 100 meters (300 feet). feet). Your Your watch watch should also have a way to measure measure elapsed time with with one of the followi following: ng: • A rotating bezel around the dial dial of the watch. • Astopwatch feature. feature. Underwater Underwater dive timers timers are designed to measure elapsed elapsed time time and have a valuable valuable feature not found in most dive watches. A pressure-activated pressure-activated switch switch starts the timer when you leave the surface and shuts off automat ica ically lly when you come back to the surface. The dive timer autom automatica atically lly records records the elapsed elapsed time of your dive without action on your part. With mo most st watches, atches, you must remember remember to set the recording recording mechanism at the start of the dive and check it it at at the end end of the dive.
Dive C o m p u t e r s Dive computers computers also measure the length of your bottom time as well well as many other items. Computers
□
NAU I Scuba D i ver
F IGI G U R E 2 3 1 . W A T C H E S FO F O R D IVI V I N G M U S T R E D E S I G N E D TO TO W IT H S T A ND P R E S S U R E .
are the most most convenient method of keeping track of your bottom time as well well as your your depth. The dive computer combines your depth gauge, tim tim ing device, thermometer, and sometimes your sub mersible pressure pressure gauge in one unit. unit. Newdive computers are introduced every year, with mo more re features available. available. At a minimum, minimum, a typical typical dive computer re records cords or displays displays the following following information: • Maximum Maximum depth [jTI • Current depth epth • Actual dive time • Remaining allowable dive time Between Between dives, the computer computer can display display inform informa a tion from from your previous dives dives as well as the the amount of time that you have been been out of the water. water. The computer computer can also help you plan your your next dive by tellin telling g you how long you can can stay at different depths. See See Chapt Chapter er5 for fo r detailed information about abou t dive computers.
3
B a c k u p I n s t rur u m e n t a tit i o n Even the best best instruments instruments can sometimes sometimes fail fa il or malfuncti malfunction. on. Having an instrument fail fail does not neces neces sarily sarily mean an emerg emergenc ency, y, but it it can end your diving day unless unless you have a back backup. up. If you use a bottom bottom timer, you should back it up with a watch. If you use use a dive computer, computer, you should back it it up with with a second second computer computer or a watch and a depth depth gauge. If you use an air-integrated computer, computer, you should back it up with a submersible pressure gauge, depth gauge, and watch.
S!
Rinse your instruments instruments in clean, fresh water at the end of each diving diving day and have your instruments inspected inspected and serviced on once ce per year by a qualified qualified repair technician. technician. Instruments are highly highly reliable, but they can go out of calibr calibrati ation. on. Also, O-ring O-ring seals can wear out and must be be replaced or water can can flood flood the instrument. If salt water get gets into an instrument and and stays inside, the instruments are quickly ruined. Do not subject watches to extreme changes in tem perature, such as by wearing them in a hot shower shower follow ing a cold-water dive. The extreme change in tempera ture can cause condensation condensation in the dive watch and ruin ruin the mechanism. mechanism. It is also possib possible to ruin the seals in a watch in this way, which w wililll cause the watch to flood.
V e r i f y W h a t Y e n H a v a L e a r n e d Review the following following questions about instrumentation: 13. A calculates your remaining remaining allowable allowable bottom bottom time time while diving. 14. A diving diving watch must be and measure while under water. 15. Proper maintenan maintenance ce of instruments includes and ______________________
________________
____________________
______________________________
B U O Y A N C Y C O M P E N S AT O R A buoyancy compensa compensator tor (BC (BC), ), enables enables you to to control control whether you floa floatt on the surface of the the water, hover in the water, or sink to the the bottom bottom. You control this by adding adding air to or venting air air from your BC. By
controllin controlling g the amount amount of air in your BC, you can pre cisely control your buoyancy. buoyancy. Buoyancy control is one of the mo most st important skills you will will learn as a diver. diver.
All BCs are made made of durable material material that can hold air air and are designed for rugged rugged use. use. Alternativ Alternatively, ely, a
Chapter 2- Diving Equipment
button before you stop blowing or take your mouth off the mouthpiece mouthpiece,, or air air wil willl flow flow out out of your BC. On some BCs, you can pul pulll down on your your inflator/d inflator/deflat eflator or hose hose or bleed valve activato activatorr to open open the overpressure ressure relief relief valve or dump valve. Some BCs have the dump valve valve located located elsewhere on the BC. Pulli ulling ng on a knob knob attached to a cable that hangs from the valve valve opens ens this valve. Alternatively, Alternatively, to deflate or bleed bleed air from your BC, you can lift your inflator/ inflator/ defla defla tor hose hose over your head and press the deflator/oral infl infla a tor valve button. button. This allows air air in in your BC to flow up up and out the inflator/defl inflator/deflator ator hose. se.
Far Ymirlntormlm Some older BCs were equippe equipped d with carbon dioxide
F IGI G 2 3 2 . T H E L O W P R E S S U R E I N F L A T O R D E V I C E (P( P O W E R III I U FLF L A TOR) IS ATTACHED TO YOUR CYLINDER WITH A LOW PRESSURE HOSE.
m
plastic plastic bladder that is inside the BC BC might hold the air. The amount amount of air the BC can hold determines determines its avai avail l able lift capacity. You use the lift lift capacity capacity to offset offset any weight you and your gear might might develop develop in the water. water. BCs must be equippedwith with an overpressure relief valve to prevent damage to the BC from from too much interna internall air air pressure. The BC must also have an infla tor/deflator hose that is at least 2 centimeters centimeters (3/4 inch) inch) in diameter. At the end of the inflator/defl inflator/deflator ator hose is a power-in power-infl flato atorr mechanis mechanism m and a deflator/oral deflator/oral infla infla tor valve. All BCs are also equipped with with a mouthpiece at the end end of the inflator/d inflator/deflat eflator or hose hose that enables you to inflate the BC byblowing air air into it (figure (figure 2-32). 2). The power-inflator mechanism is is attached attached to the reg ulator ulator first first stagewith with a low-pressure inflato inflatorr hose. The power-inflator mechanism enables you to add air air to the BC directly from your cylinder by pushing a butto button. n. If your power-inflato power-inflatorr mechanism fails or you have no ai airr in your cylinder, you can oral orally ly inflat inflate e your BC by press ing the deflator/oral deflator/oral inflato inflatorr valve button and blowing into the mouthpiece at the same time. Stop pressing the
(C02 (C02) cartridge cartridge inflator inflator mechanisms. mechanisms. These These mecha nisms were designed to be used in an emergency only, but the mechanisms mechanisms could corrode easily if they they weren’t maintained properly and they they were were unreliable. You can still till use a BC that is equipped equipped to use a C02cartri C02cartridge dge infla inflator tor mechanism as long as it has been been equipped with a plug to avoid air air loss. Avoid using the mechanism.
Types There are are three general general types of buoyancy buoyancy compen sators sators (BCs) (BCs):: back flotation, flotation, jackets, and horse horse collars. Some BCs have integrated integrated weight system systems. Some BCs combine features features of more than one type.
B a c k F lol o t a tit i o n Back-fl Back-flota otatio tion n systems are designed so that that the entire entire bladder of the BC is behind you. you. This leaves your chest and waist uncluttered. Back-flotati Back-flotation on systems are popular popular for underwater photog photography raphy for this reason. reason. Back-fl Back-flota otatio tion n systems provide goodtrim as you swim under water becaus because e the air air in in the bladder on your your back counteracts the weights you wear around your waist. Howeve However, r, on the the surface, the the back flotati flotation on can tend to push you face down in in the the water unless you actively kick or recline recline to mainta maintain in a faceface-up up position. position.
NAUI Scuba Diver
Jackets Ja Jacket-style BCs are the most popular buoyancy compensators. These BCs are designed designed so that that the blad blad der wraps from your back around to your waist (figur (figure e 2-33). These BCs are comfortable comfortable to wear, provide good trim trim under water, and float float you upright on the surface when your BC is inflated.
Horse Collars The older horse horse colla collarr design encircles your your neck. You can use a horse collar collar for for both skin and scuba div ing. The adjustment adjustment of the harness is critic critical al to keep the BC from from riding riding up when it is inflated. inflated. You must don don and remove remove the horse horse colla collarr separately from y your our cylind cylinder. er. Always remember to detach the low-pressu low-pressure infla inflator tor hose when removing removing your cylinder. cylinder.
I n t e g rar a tet e d W e igi g h t S y s t e m s Some jacket-style and back-flotati back-flotation on BCs enable you to integrate or add your your weights direct directly ly to the BC instead of wearing wearing them on a weight belt. The BC must have a means of allowing allowing you to quickly quickly release release the weights weights in an emergency. Some integratedintegrated-weight weight systems use pockets that you load with with weights and then secure in your BC BC with Velcro Velcro™. ™. In an emerge mergency ncy,, you pull pull the entire entire pocket out of the BC and drop it. Other integratedintegratedweight system systems have pockets that are secured at at the bot tomwith a threaded threaded cable. cable. You load your weig weights hts direct ly into into the pockets in the BC. In an emergency, you pull pull the cable and the weights drop out of the pockets. The advantages to an integrated-weight BC include: include: • The need to wear a weight belt belt is elimin eliminated ated.. • The weights cannot slide around around your body. dy. • The weight is not supported solely solely by your lower back. One disadvantage to an integrated-weight integrated-weight BC is that once it is is assembled, it can can be heavy and awkward to handle. If you need need to carry the system systemfor any distance, you must either either remove the weights or wear wear the system. Apotential potential major major hazard is that iitt is impossible for a dive supervisor supervisor to tell tell at a glance approximately approximately how
F IGI G U R E 2 3 3 . J A C K E T - S T Y L E B C S A R E T H E M O S T P O P U L A R STYLE OF BC.
much weight you are wearing (for (for example, wheth whether er you are obviously obviously overweighted). overweighted).
Selection The best way to select a BC is to try on different different models and see seewhic which h one is the most most comfortable comfortable for you. Also, the features and design of the BC should match the type type of diving you will will be doing. For exam ple, if if you are going wreck diving, rugged materia materiall is more mo re critical. critical. If possible, try on tthe he BC with a cylinder cylinder attached to the backpac backpack k and try the the unit, or a rental like it, it, in the water. Ensure that you inflate inflate the BC to see how how it feels when full full of air. air. The BC BC should not interfere interfere with your body movement ovement when it is full full of of air. The controls must must also be easy to to locate locate and and operate.
maintenance You should rinse your BC intern internall ally y and externally m after each diving day (figure (figure 2-34). 2-34). Salt Salt water, water, dirty
Chapter 2- Diving Equipment
i v i n g E q u i p m e n t
F IGI G U R E 2 3 4 . Y U U S H O U L D R I N S E Y O U R B C INI N T E R N A L L Y A N D E X T E R N A L L Y A T T H E E N D O F E A C H D I V INI N G D A Y
water, water, or chlorinated water inside your BC can cause cause damage. Every time you bleed bleed air from your BC under water, some water water gets into the BC. Rinse the inside of your BC using using the following following procedure: 1. Fil Filll the inside of the BC with fresh water through the oral inflator inflator mouthpiece mouthpiece.. 2. Slosh Slosh the water around around inside the BC thoroughly, thoroughly, turning turning the BC upside down and right side up. 3. Drain Drain the water by turning turning the BC so that the inflator/def inflator/deflator lator hose outlet is the lowes lowestt point and pressing the deflator/oral deflator/oral infla inflator tor valve valve but ton to allow the water to drain out of the mouth piece (figur (figure e 2-35). Rinse the exterior of the BC thoroughly, thoroughly, as well as the power-inflator hose. ose. Infla Inflate te the BC to allow allow it to dry completely. completely. Store the the BC in a cool, dry place with air in the bladder. BCs must have their power-inflator mechanism inspected once per year. If it is not serviced, it can mal mal
F IGI G U R E 2 3 5 . B E S U R E T O D R A I N A L L T H E W A T E R O U T O F T H E BLADDER AFTER RINSING.
function. You should should also inflate your BC completely to to check for leaks leaks before each dive trip.
V e r i t y W h a l Y o u H a v e L e a r n e i Review the following following questions about buoyancy compensators: 16. The three main main types of BCs are ., and 17. The two essential essential features found on all BCs are are and ___________________________
18. Why should you rinse the the inside of your BC?
N A M S c u b i D ivi v e r
W E IGI G H T S A N D W E IG I G H T B E L TS TS You wear lead weights when when you are diving diving to offset the buoyancy buoyancy of your body, body, your your wetsuit, and other div div ing gear gear you are are wearing. Weights are availa available ble in in many configurations configurations and as you gain diving diving experience, experience, you will will find the configuration that fits you best. st.
T y p e s o f W e igi g h t s Weights come in ma many ny different different shapes and sizes (figure (figure 2-36). Mo Most st commonly, you will ill find find lead mold mold ed into cylinders cylinders or blocks with slits slits to enable a weight belt to be threaded through the weight. The block of lead can be uncoated uncoated or coated coated with a plastic plastic covering. Some of the larger larger blocks of lead are curved to fit fit the hip and are known aship weights. Solid Solid lead weights weights come in sizes from 0.5 to 6.5 kilogr kilograms ams (1 to 14pounds). pounds). Lead can also be be molded into cylin cylindr drica icall shapes shapes with a slit slit in the middle to enable a weight belt to pass through. through. These are calle called d bullet weights. Bullet weights typica typicalllly y come in sizes from 0.5 to 2.0 kilogra kilograms ms (1 to 4 pounds). pounds). Also, lead shot can be sewn sewn into pouches of various various soft weig weight ht.. Soft sizes. This This type of weight weight is known as a soft \{J2 weights conform to the shape of your hip hip and are are more comfortable comfortable to wear. Soft weights also cause less dam age to a deck or injur injury y to a person if they are dropped.
W e igi g h t B e l lsl s , H a r n e s s e s , ana n d W e igi g h tit i n g S y s t e m s The simplest and and most common weight bel beltt is a 5.0 centimeter (2-inch) (2-inch) wide nylon web web belt belt with a metal or plastic plastic buckle (figu (figure re 2-37). Weight keepers are used on this type of weight belt to keep keep the weights from shifting shifting on the belt. Some weight belts are composed of a series of of pock ets attached to a nylon web web belt. These pockets will ill hold hold either solid weights weights or soft soft weights. weights. There are also shot belts belts that have one continuous compartment fille filled d with lead shot. shot. The compartm compartments are filled filled with with different different weights weights of shot shot and you simply choose the weight weight you need. Another type type of weight belt is a stretchable/ com
F IGI G U R E 2 -3- 3 6 . W E IGI G H T S C O M E I N M A N Y D I F F E R E N T W E I G H T S A N D S I Z E S .
F IGI G U R E 2 - 3 7 . W E IGI G H T B E LTL T S C O M E INI N M A N Y S T Y L E S .
pensating belt with a quick release buckle. This type type resists slipping, slipping, compensates for suit suit compression, spring ngss off your releases releases cleanly, cleanly, and spri your body if you must ditch the weight belt. A weight harness, harness, usua usually lly used with dry suits, uses uses a belt and shoulder shoulder harness systemto support the weights weights on your shoulders rather than around your waist. This helps reduce reduce strain strain on your lower back and helps pre pre vent the belt from sliding sliding around your body. body. A desirable safety feature of many weight belts is the abili ability ty to compen compensate for the compression compression of a wetsuit as you descen descend under water. Without Without a compensating fea ture, weight weight belts become looser at depth. A loose weight belt can slip down belowyour waist waist or can rotate to place the buckle at your side or back instead of in the front where it should be.
Chapter 2- Diving Equipment
The length of your weight belt belt must be be adjustable so there is not an excess of belt to pose a quick-release quick-release hazard. hazard. Your instructor instructor will will showyou several meth methods ods of adjusting adjusting your weight bel beltt so that you do not need need to cut the end end of the the belt. The tail tail of the belt should not be longer than needed to provide provide a tightenin tightening g grip of about 8 to 10centimeters (3 or 4 inch inches es). ). One advantage to the wire cam buckle is is the complete abs absenc ence e of a tai tail.l.
Q u i c k R e l e a s e o f W e i g h tst s No matter what what type of weight weight system you choose, choose, you must have have a means of ditchin ditching g the weights with one hand. This type of system is known as a quick quick release. The plastic or metal buckle buckle on a weight belt must be a quick-release quick-release buckle that open opens s by pullin pulling g on the end of the weight belt or on the buckle. buckle. You can then pull pull the weight belt free from your body by grasping the buckle and pullin pulling g the belt away as as nee neede ded. d. Integrated Integrated weight systems in BCs use either pockets that can can be quickl quickly y pulled out of the BC and dropped or a cable that can be
DIVING SUITS Your normal body body temperature temperature averages about 37°C (98.6 (98.6°F). °F). Your skin will will be cooler, cooler, but but any time time the water water temperature is colder than than your your skin tempera tempera ture, your bodywill ill lose heat to the water. Divers must must wear a thermal-protec thermal-protection tion diving suit in all but the warmest waters (fig (figure ure 2-38 2-38). It is essential to wear the right thermal protection for the conditions where you dive. dive. When you grow cold under water, water, you lose your abi abilit lity y to perform at your best. Heat loss loss under under water water affects your abi abilit lity y to think, and you fatigue rapidly. Cold water is a contributing factor in many diving accidents. The amount of insu insulat lation ion you need to to wear on a dive depends on the water temperature, your your activi activity ty level during during the dive, and other factors such as your build, build, body body fat, and so on. In colder water, water, every diver needs eds to wear more insulatio insulation n than than they would wear in warm water. The harder you work under water, the more heat your body generates, nerates, and the warmer you are, unless you fai faill to wear adequate protection.
pulled pulled to drop weights out of the bottom of the BC.
V e r i f y W h a t Y o u H a v e L e a r n e d Review the following following questions questions about weight belts: belts: 19. The most importa important nt feature feature of of a weight belt belt is . the _______________________________
20. A compensating weight weight belt belt
21. Divers might might prefer soft weights over molded molded lead weights weights because because
__________________
_______________________________
and
F IGI G U R E 2 3 8 . D I F F E R E N T D I V I N G S U I T S A R E N E E D E D T O A L L O W Y O U T O D I V E I N W A T E R F R O M F R I G I D T O T H E W A R M E S T T R O P I C A L W A T ER S .
05332674
NAUI Scuba D iver
Different ranges ranges of temperatures temperatures feel comfortable to different divers. divers. You might wear more more or far far less insula insula tion than your dive instructor instructor or bud buddy. dy. It is essential to wear what feels feels right right for for you, rather rather than what what someone
□
tells you to wear. In the warmest tropical tropical waters, you might be able to dive in just a skin suit. In colder water, water, you will ill need a wetsuit. In the coldest waters, dry suits suits are the most effective form of thermal insulatio insulation. n. Dive suits also provide protection from cuts, scrapes scrapes,, and stings. stings. Even if the water isn’t cold, you should wear some type of protective protective covering covering to avoid inju injurie ries s and sunburn.
Dive Skins Dive skins are thin thin,, one-piece suits designed to pro tect your skin from cuts, scrapes, scrapes, and stings that can occur when when you you dive in tropical tropical waters. The term dive skins covers covers a wide range of products made made from differ differ ent materials. materials. To determine what you are buying, it is important important to ask what materi material als s were used to make the suit. Two Two comm common on materials materials are Lycra® and Polartec®.
Lycra® By themselves, Lycra® Lycra® dive skins provide provide only min mini i mal thermal thermal protection (figur (figure e 2-39), 2-39), but Lycra® can be combined combined with polypropylene, which is is a plush fabric, fabric, or other insulating materials materials to add som some thermal capabi capabil l ity. Lycra® dive skins, skins, like like wetsuits, provide almost no protection from the wind, especially especially when they are wet. This can can be a problem problem on the surface with many suits, where heat is lost as water outside your suit suit evaporates evaporates and carries heat away from yo your ur body.
Polantec® Polartec® is a combination of Lycra® and a velour fleece fleece thermal lining lining that traps traps air air and water as as insula insula tion. Dive suits made made from Polartec® Polartec® provide the the warmth of a thin thin neoprene neoprene wetsuit without the need to wear as much weight to compensate compensate for the buoyancy buoyancy of the suit.
F IGI G U R E 2 3 9 . S K I N S H E L P P R O T E C T Y O U F R O M C U T S , S C R A P E S , A N D S T I N G S .
W e t s u iti t s Wetsuits are made from foam neoprene neoprene,, which which is a synthetic rubber fil fille led d with thousands thousands of tiny tiny gas bub bles. Neopren Neoprene e provides good insulatio insulation n in many diving situations. situations. Wetsuits are the most widely widely used used thermal protection for dive divers rs becau because of their simplicit simplicity y and rela rela tively low initial cost. To work properly, a wetsuit must fit fit your body body quite precisely, and snugly. Once Once you you enter the water, a thin layer layer of water is trapped trapped betwe between your skin and the inner surface of your suit. The water water is then warmed warmed to your skin temperature temperature and the insula insulating ting suit keeps keepsyou, and the water, warm. If you do not dive d dee eep or make multiple multiple dives in very cold water, a wetsuit will will provide provide you you with reason reason able insula insulation tion.. As a wetsuit ages, ages, it loses some of its insulating insulating capabilit capability y because some of the cells (gas bub bles) with within in the wetsuit break down on each dive. Wetsuits come come in a variety variety of colors. The color color is usuall usually y in the nylon coating coating on the outside and inside of the neoprene neoprene materia material.l. Nylon provides provides better durab durabili ility ty and makes the wetsuit easier to put put on and take off, but it makes makes the the wetsuit wetsuit slightly slightly thicker.
Ch apter 2- Diving Diving Equipm Equipm ent
Thicknesses Wetsuits are avail available able in many many thicknessesfrom 2 millimeter millimeters s (mm (mm)) to 7mm and in many many different styles. styles. The thicker the suit, the greater the insulation, insulation, although thick thick suits can bebulky bulky and awkward towear. The most popular thickness of a wetsuit for warm water water to 27°C (80° (80°F) F) is 3mm. In colder waters, most divers prefer a suit thickness of 6 mm or greater.
i v i n g E q u i p m e n t
Styles Shorty Shorty wetsuits (wetsuits (wetsuits with with short sleeves sleeves and thigh-length legs) legs) and 2 mm or 3 mm full-body suits are popular for wear in tropical tropical temperature temperature water. For colder water diving, diving, some divers prefer to wear a bib overall overall set of pants known as a farm er john and a combination. They also wear a hood, step-i step-in n jacket combination. booties, and gloves. You can adjust the warmth of your wetsuit by layer winter, you might wear a vest ing. For example, in the winter, or a hooded vest underneath your farmer farmer john john to add insulatio insulation. n. In the summer, you might be able to dive without a hood.
F IGI G U R E 2 4 0 . D R Y S U ITI T S K E E P Y U U W A R M E R T H A N W E T S U ITI T S IN COLD WATER.
which you will will be doing mo most st ofyour diving. Their Their rec ommendations will ill help help you select the most appropriate type type of suit. suit.
Options
Dry Suits
If you are tall, thin, very very muscular, or o otherwis therwise e dif fer from standard s sizes izes, you might might want to consider hav hav ing your wetsuit custom custom made made toyour measurements. measurements. If you have a wetsuit wetsuit custom-made, you can choose from a wide range of options. options. Options for wetsuits can include include:: • Zippers Zippers at the wrists and ankles to make the suit easier to put on. Howeve However, r, water can enter and leave the suit through the zipp zippers ers,, chi chilli lling ng you. • Knee pads to protect your your knees and the su suit it from sharp rocks. • A spine pad to cushion cushion the cylin cylinde derr and keep the spine warmer. • Pockets inside the wetsuit to hold keys. keys. • Sheaths built built into into the leg to hold a dive knife. • Attached Attached hood for extra extra warmth. Talk to your NAUI Pro Center Center and dive instructor about the types of suits used used in your your area or the area area in
Dry suits are preferred for colder water. Dry suits are much more expensive expensive than wetsuits, but are well worth the cost for the increased comfort in many many diving diving situations. situations. A dry suit suit is designed designed to keep you dry. The suit keepsyou dry by using a c combin ombinatio ation n of wrist seals, a neck seal, and a waterproof zipper zipper (fig (figur ure e 2-40). 2-40). With With some non-neopren non-neoprene e dry suits, you we wear ar under wear under the sui suitt to add insulat insulation ion and keep keep you warm. The underwear trap traps s air between between your skin and the suit. You can layer layer the underwear to adjust your insulatio insulation n for any water temperature. temperature. The water tem perature, your bo body dy structure, and your activity activity level level during during the dive determine the amount amount and type of underwear underwear that that you wear beneath your dry suit. Dry suits are easier to put on than wetsuits, wetsuits, but it does take specialized specialized or additional additional traini training ng to learn how to use them properly. Most dry suits are bulki bulkier er than
m
a
NAU I Scuba Sc uba D i ver
wetsuits. wetsuits. Dependin Depending g on the fit of your suit suit and the type of insulati insulating ng underwear you use, use, you might need to wear moreweight with a dry dry suit than with with a wetsuit. wetsuit.
Types There are many different types of dry suits. Dry suits can be made from foam neoprene, solid solid neoprene, or a variety variety of of heavy-du heavy-duty nylons with water waterproof proof mate rials laminated to them. The foam neoprene suits are are one-piece suits that that have a waterproof zipper and seals at the wrists and neck. The suit itself provides provides insulati insulation. on. This suit is warmer than a wetsuit made made out of the same same material material because the inside of the suit is dry dry and the air air in the suit as well as the suit itself itself provide insulatio insulation. n. The solid neopren neoprene e suit requires requires that undergar undergar ments beworn under the the suit for additi additional onal insulati insulation. on. The amount of insulation insulation worn can can vary depending on the temperature of the water. This suit suit is less less bulky than the foam neoprene suit. The nylon-shell suit is loose fitting, fitting, whic which h gives you greater greater mobility mobility and comfort. comfort. The nylon shell shell suit also requires that that undergarments undergarments be worn.
Features Most of the options options availab available le for for wetsuits, wetsuits, such as pockets, knife sheaths, and kneepads, are also avail availab able le for dry suits. suits. Other options made especially for dr dry y suits suits include: • Dry hoods • Dry gloves • Attached hard-sol hard-sole e dry boots Because dry suits do not need to fit fit as closely closely as wetsuits, custom fittin fitting g is rarel rarely y necessary necessary. However, ever, the cost cost of dry suits is st still ill greater because cause of the special watertight watertight zipper zipper and and the other materials materials and labor labor needed to make the sui suitt waterproof.
Buoyancy Control While diving, you control the amount of air in your dry suit with an infl inflator ator valve, which allows you you to add
air air to the suit, and an exhaust valve, valve, which allows you to bleed bleed air air from the suit. The inflator inflator valve is similar similar to the power inflat inflator or used on a BC. You add air to the dry suit suit as you dive deeper and then bleed air air as you return to the surface. surface. The most common common location location for the inflator inflator valve is in the middle middle of the the chest chest so it will will not interfere with your BC jacket. The exhaus exhaustt valve is a low-profile va valve lve that usually automa automatic ticall ally y vents vents air air as you ascen ascend. d. A common common loca tion for the exhaust valve is on the outside of your upper left arm. Different Different valve models bleed air air at different rates. A valve valve that vents quickl quickly y is better, better, because it allows you to blee bleed d air air from your suit suit faster. faster. When you dive with a dry suit, you use the dry suit for buoyancy control and and the BC for surface flotation. flotation. You use the BC for backup backup buoyancy control. You must must be very careful careful if adding air air to both your dry suit and the BC under water because it is diffic difficult ult to control both both pieces of equipment at at the same time. You must always wear a BC with a dry suit. suit. If you are taking your NAUI Scuba Diver Diver certifica certifica tion course course in an area of the world that normally normally requires dry suits (for (for example, Alaska or Canada) you will probably be diving in dry suits suits from your very first class. class. If this is the case case, your instructor w will ill presen present sup plemental material material and training training soyou will will understand understand how to use use your dry suit. If your class does does not include traini training ng in dry dry suits and you decide to to buy one, one, you m need need to take a NAUI Dry S Sui uitt Special Specialty ty course to leam how to use use the dry suit suit properly.
Hoods You lose the greatest amount of heat from your m head, hands, chest chest and armpits, and groin. Therefore, thermal protection for your head is critic critical al when you are diving. In cold water, water, you can lose lose a significant significant amount of your body heat through your head alone. For most cold-water cold-water diving, diving, you can use use a simple hood made made from wetsuit material material (figure (figure 2-41). The that tucks under the hood can have an attached bib that colla collarr of your wet suit to kee keep p your neck warm and help keepwater from circu circula latin ting g in and out down down the back of your neck. neck. The warmest arrangement is to have have
Ch apter 2- Diving Diving Equipm Equipm ent
F IGI G U R E 2 - 4 2 . W E T S U I T S C A N B E D R IEI E D A N D S A F E L Y S T O R E D O N W I D E H A N G E R S M A D E F O R W E T S U ITI T S . F IGI G U R E 2 4 1 . W E A R I N G A H O OD OD H E L P S Y O U C O N S E R V E B O D Y H E A T.T .
your hood attached to your suit. If you are diving in colder water, you might want to use use a dry hood attached directly directly to a dry suit. The dry hood keeps your head completely completely dry. Most hoods are fair fairly ly uncomfortable out of the water. However, once you are under water they are almost almost unnoticeable. unnoticeable. Pressure Pressure equalization in your ears when you you wear a hood hood may require special special attention. Your instructor instructor will will address ress any special techniques needed for the the type of gear you are wearing. wearing.
your resistance resistance to cold might be less. less. For example, if you live in a dese desert rt climate, you might have to wear more insula insulatio tion n because your body is accustomed to high temperat temperatures ures.. If you live in a cold climate, you might be wearing wearing less insulati insulation on in the water because your your body is accustomed to colder temperatures. temperatures. Use the following general guidelines guidelines when when deciding what type of diving suit to wear: • 27°C (80°F) and warmer water.
A skin skin suit suit is is recommended. • 24°C to 27°C (75°F to 80°F) waters.
A 2 mm to 3 mm full full wetsuit or shorty shorty is recommended. • 13°C to 24°C (55°F to 75°F) waters.
C h o o s i n g t h e C o r r e c t S u i t t o r t h e C o n d i tit i o n s Some insulation is required for most diving activi ties and having the correct suit for the conditions conditions is one one of the the keys to enjoying a dive. The correct suit fo forr you might not be the correct suit suit for for your buddy because ecause your reaction reaction to cold might be be quite different. Also, Also, depending depending on the area of the the world in in which which you live, live,
A 5mm 5mm to 7 mm full fu ll wetsui wetsuitt is suggested. As the water gets colder, colder, you also need to wear a hood and gloves. • 2°C to 13°C (35°F to 55°F) waters.
A full full dry suit is recommended. • 2°C (35°F) and colder water.
Special Special traini training ng and equipment are neede needed to dive in water this cold.
NAUI Scuba Diver
V e r i l y W h a t V o n H a v e L e a r n e d Review the following following questions questions about diving diving suits: 22. A is suitable for only warm, tropical diving. __________________________
23. A is made only only from foam neoprene. 24. A uses under under garments for insulation. 25. True or False. You do not need special trai trainin ning g to use a dry suit. __________________________
__________________________
A C C E S S O R Y E Q U I P M E N T F IGI G U R E 2 -4- 4 3 . Y O U S H O U L D A T T A C H Y O U R D IVI V INI N G I N S T R U M E N T S T O Y O U R R C S O T H E Y D O N O T D R A G A L O N G T H E B O T T O M .
Maintenance You should should rinse a diving suit suit with fresh water after every diving diving day. Rinse dive skins and wetsuits inside and out. out. There are commercial commercial products products you can use at the end end of a dive trip to clean clean your dive suits completely before storage. You should store your wetsuits on wide hangers designed especially especially for wetsuits (figur (figure e 2-42), or unfolded, lying flat. If you get a hole in your wetsuit, wetsuit, you you can repair it with with wetsuit cement cement and neopren neoprene patch material material.. If the inside of a dry suit is completely dry, and it is worn with under clothing, you only need to rinse the the out side of the dry suit. You need to elimin eliminate ate sweat, dead skin, and soon, from neoprene dry suits by rinsin rinsing g the suit inside and out. out. All dry suits should should be occasionall occasionally y rinsed inside inside and out. You should should lubricate lubricate dry suit zip pers with only only paraffi paraffin n wax, beesw beeswax, ax, or preparations pro vided by the manufacturer manufacturer.. Your dry suit can be stored stored rolled rolled up in a bag away from heat and ozone-produ ozone-producing machine machinery ry such as hot-water heaters and electric electric motors. Your dry suit, with with its valves, zippers, and seals, seals, should beinspected ected annually annually by a qualified qualified repair technician. technician. Dry-suitvalves can malfuncti malfunction on if if they are not regularly regularly serviced. Your dry suit owner’s manual should be your pri pri mary guide guide and will list any special special care instruction instructions. s.
Accessorie Accessories s are availa available ble that can can make diving diving more enjoyable. There are also accessorie accessories s for specialized activiti activities. es. Some Some of of the availa available ble accessories accessories are described as follows. follows.
A t t a c h m e n t D e v i c e s Clips enable you to attach your instruments instruments to your BC. Withou Withoutt clips, clips, your gauges and octopus regulator regulator will natur naturall ally y hang at your side, side, and a foot or more more below your waist, as you swim horizontal horizontally ly through the water. If you are swimming close to the bottom bottom, your instruments can can strike and damage damage marine life life,, or be damaged thems themselves. elves. When corals and other delicate organisms are broken, they do not grow back. They die. Remember Remember to clip your your instruments instruments to your BC on every dive to avoi avoid d damage to them or the underwater environment. environment. The clips clips you use must must be be fastened fastened so you can remove remove your BC easily easily and quickly in an emergen emergency (figur (figure e 2-43). Accessory clips clips and other holders holders are availa available ble at most most dive store stores.
Knives A dive knife is a working tool used used for many pur pur poses. Its most important important function function might might be to cut fish fish ing line line or nets nets if you get get tangled in them under water. water. Knives are not used asweapons to figh fightt sharks, as you might might have seen seen on on television. television.
Ch apter 2- Divi Div ing Equipm Equipm ent
F IGI G U R E 2 4 4 . S E L E C T T H E K N IFI F E M O S T A P P R O P R I A T E FO FO R T H E D IVI V INI N G Y O U U S O A L L Y D O .
There are many diff different erent styles and s sizes izes of diving diving knives and you should select the knife mo most st appropriate for the diving diving you do (figure (figure 2-44). For example, an underwate underwaterr hunter might want a knife with with a thin, sharp sharp blade, blade, while while a wreck diver might want a heavy knife with a blunt tip for for prying and pounding. pounding. All dive knives should be be kept sharp and have their their blades blades coate coated d with a thin thin layer of oil when they are not not in use. use. Even stainless-stee stainless-steell knives can rust rust if they are not properly maintained. Keepyour dive knife knife in its sheath when it is not in use. use. Sheaths are usual usually ly made made from plastic plastic and can be mounted mounted in different places including: including: • On the the inside of your cal calf. f. • On the back of your instrument instrument console. • On your your BC pocket or shoulder shoulder strap. How and where you mount mount your your knife knife depends on the design design of the sheath, sheath, the size of the knife, and your individual individual prefere preference nce..
bag as a gear bag. Nylon is is usually usually better because because it does not rot or mildew as easily easily as canvas. Mesh bags or panels help any any wet gear in the bag to dry. dry. You should mark all all your gear with som some personal personal mark, and your bag with your your name, address, and telephone number number so it can easily easily be be identified in case case you you accidentally accidentally leave it on a dive boat. Special Special gear bags are availab available le at dive shops. ops. These These bags bags are the easiest to to use for diving diving because they usual usual ly have special compartments for fins, regulators, regulators, and instruments. Many Many of the bags are padded for air airliline ne travel and even have wheels so they roll roll through airports airports or on wharves. wharves. Some of the the bags bags have have special special dry com partments for your logbook, logbook, clothing clothing,, and other items items you do not want want to get wet.
D i v e F l a g s and Floats When you you are diving, it is almost impossible impossible for a boat or jet jet ski moving moving at at high high speeds to see your your bubbles or for their operators to know you are in in the area. To avoid an accident, accident, you should use a special diver down flag to let others know you are under water. The United States States dive flag is a red flag flag with a white diagonal stripe running running from the upper-inner upper-inner corner to the lower lower-ou -outer ter (fly (fly)) corner of the flag (figure (figure 2-45) 2-45).. This flag must be flown from your surface support sta tion or boat any time you have scuba scuba divers in the area. Many states states require, by law, that this this flag flag be flown when divers divers are in the water. It is your obligation to stay stay within within a set set distance distance of the the flag (no more than 30
U.S. Dive Flag
Internationa l Diver Code "Alpha"
Gear Bags You need a gear bag to transpor transportt your gear to and from the dive site and keep keep it safe, clean, clean, and out of the way at the site. Without a gear gear bag, bag, it is diffic difficult ult to han dle your equipment equipment and easy easy to drop delicate delicate gear. On a charter dive boat, boat, it it is easy to lose lose your gear or have your gear accidental accidentally ly picked up by by other divers unless you have a bag to keep it in. in. You can use almost any heavy-duty heavy-duty nylon or canvas
FIGURE 2-45. ALWAYS HAV E A DIVE FLAG FLYING W HEN DIVERS A R E I N T H E W A T E R .
I\IAUI Scuba Diver
F IGI G U R E 2 - 4 6 . A S U R F A C E F LOL O A T G I V E S Y O U A P L A C E T O R E S T O N THE SURFACE.
m
meters [100 feet], but local laws might require less). It is also your obligat obligation ion to take the flag down when all all divers are are out of the water. When appropriate, dive boats boats must fly the intern interna a alpha flag fla g when tional blue and white alpha when divers are in the water (figure 2-45). This signal flag indicates that the the boat’s maneuverabi maneuverability lity is limited limited becaus because of diving diving activ activ fla g in ities. This This flag is also used used as the diver down flag in many countrie countries. s. Your instructor wil willl let you know know what the local regulations are for dive dive flags. If you are shore diving, diving, your surface surface support support station can be anything anything from an inflata inflatable ble inner inner tube tube to an inflatable inflatable surf mat or kayak (figure (figure 2-46). 2-46). It does not matter what what you use as long as some type of object appropriate for the conditions and area area that can can support support you is nearby in in case you need need it.
Logbooks E 3
A logbook logbook is your record of experience experience in the water (figur (figure e 2-47). You should record the informatio information n from every dive you you make in your personal logbook soon after you leave the water. In some parts of the world, world, there are laws requiring requiring that you log log your dives. dives. You will will be required to use use a logbook logbook during your NAUI diver-training diver-training course courses. In addition, addition, some dive operators operators will will want to review your logbook before before they
F IGI G U R E 2 4 7 . Y O U R L O G B O O K R E C O R D S Y O U R E X P E R I E N C E INI N T H E W A T ER ER .
make diving diving services availab available le to you. you. If you decide to continue continue your education education on to diving leadership, your logbook shows: • That you have var varied ied divin diving g experience experiences. • You have documented documented performing performing advanced div ing skills skills under the the supervision supervision of an instructor. • How many hours you have have spent under water. • How many dives you have have made. Your training, training, diving, and hours hours will have to to be documented before before you can be accepted for leadership leadership training.
m
F i r s t A i d Kits It is is a good idea to have a first aid kit kit on any dive trip. trip. All All you need to do is add a few items to a standard first aid kit kit to meet meet the particula particularr needs of diving and you are ready to deal with typical typical minor minor diving-related diving-related inju injuri ries es.. See Appendix C for the recommended recommended items for a diving first aid kit.
O t h e r A c c e s s o r iei e s Some other useful accessories accessories are: slate so you can • An underwater slate can record data data and communicate with with your buddy buddy (figu (figure re 2-48). ,goodi diee bag bag to • A ,goo to hold game, specimens, artifacts, artifacts,
E D
Chapter 2- Diving Equipment
V e r i t y W h a t Y o u H a v e L e a r n e d Review the followin following g questions about accessory accessory equipment: 26. What is the mo most st likely likely use for a dive knife under water?
27. When you fly fly a dive flag, flag, you must ______________________________
and
28. You should record all all dives in your logbook because
___________________________
and and
______________________________
.
additional accessories accessories that wil willl be useful to 2 9 . Two additional you when when you dive dive are are __________________
and and
________________________________
F I G U R E 2 4 8 . W R ITIT I N G O N A S LAL A TE T E I S A G O O D W A Y T O C O M N I U NIN I C A T E U N D E R W A T ER ER .
trash, and other treasures. • An underwater light, light, which which is is necessary necessary for night diving, but is also good to have during the day to bring out colors colors and to peer into holes and crevices. • A marker marker buoy to mark the locat location ion of a dropped item or a specific area. • Aspare spare parts kit that that includes includes the items that can can save a dive. dive. The items items can include include a mask strap, a snorkel keeper, keeper, a fin fin strap, assorted O-rings, and a regulator mouthpiece with attachment attachment strip. • Achecklist checklist is a great way to remember all all of the gear you you need need for diving diving as well well as personal personal items. See Appendix C for samples of checklists. checklists.
_
_
_
_
.
_
CONCLUSION Diving is an equipment-intensive activity. Remember Remember that all all this equipment helps you adapt to the underwater underwater environment and function function there as com com fortably fortably and safely as p possible. ossible. The more more you work with your your gear, the easier easier it becomes to use. Once the gear is easy to use, you wil willl be able to devote more of your attention to your surroundings surroundings and activities.
CHAPTER
NAU I Scuba D i ver
LE A R N I N G G O A L S In this chapter chapter you you will: will: • Be Be introduced to the snorkeling snorkeling skills skills you will will learn during your course. • Learn the steps for assembling assembling and testing your scuba equipment. • Learn Learn the steps for donnin donning g your scuba scuba gear. • Read about some of the methods methods for enteri entering ng and exiting the water. • Be introduced to tthe he mask and regulator regulator skills skills you will learn during during your cours course. e. • Learn Learn about buoyancy control and buoyancy skills. • Be introduced to the safety skills skills you will will learn during your course. It is one thing to use use your diving diving gear in a swim ming pool or other confined water setting, but exploring open open water is the purpose purpose of scuba diving. To enjoy div div ing, you you must be able to combine your your knowledge of the underwate underwaterr environment with the abili ability ty to handle your equipment equipment under a variety variety of conditions. You must must have the confidence confidence and abi abilit lity y to operate your gear by feel, becau because se your mask mask will will restrict much of your vision. In your NAUI Scuba Diver certificatio certification n course, course, you learn the basics of divin diving, g, but you become become a knowledgeable diver only through through additional additional experien experience ce and further training. If your training is occurring during the the winter months months in an area where the the weather is cold, you still still have the option option of completing your open-w open-water training training immediately. You can complete complete your class through NAUI’s Universal Referral Referral Program by training training at a trop trop ical ical resort under the direction direction of another instructor. Ask your NAUI instructor instructor for details about this program.
SNORKELING SKILLS Developing good snorkeling skills skills is fundamental fundamental to being a good diver. diver. You must know the proper use use of your mask, snorkel, and fins.
P r e p a r ini n g Y o u r G e a r l o r U s e You need to prepare almost all all of your new diving diving gear before you can use it. This is is especially especially true with a new mask. New mask lenses are covered with with a thin thin film film of of lubricant. lubricant. You can use use toothpaste thpaste to to re remov move e this lubrican lubricantt by using the following following procedu procedure: 1. Put Put a dab of toothpaste toothpaste on the inside of each lens of the mask. 2. Rub the toothpaste over the entire entire lens. lens. 3. Rinse Rinse the mask well with fresh water. water. Washi Washing ng the lens with with toothpaste helps keep keep the lens from fogging, which which occurs when condensation condensation forms on on the inside of the lens. Each Each time you don don your mask for diving, you will will need to to prepa prepare re it sothat it will not fog because because of the temperature temperature difference difference inside inside the mask compared compared to the surrounding surrounding water. The most most common way to prevent fogging is to use the following following procedure: 1. Apply a few few drop drops s of antifog antifog solution solution 2. Rub the solution solution on the inside of the lens. lens. 3. Rinse Rinse the mask thoroughly. An alternative alternative is is to use use saliva, saliva, but many prefer prefer commercial commercial products. products. The commerci commerciall ally y prepared prod ucts ucts usually usually work mo more re effectively than saliva. To pre pare your mask properly, be sure to to read the instructi instructions ons enclosed enclosed with with the product. product. The snorkel is usu usuall ally y attached to the the left side of your mask strap if your regulator regulator comes comes around your right right side (figure (figure 3-1). 3-1). Some snorkels are design designed to be worn only on the left side. Some snorkels snorkels use a sili sili cone snorkel keeper, keeper, while while others have plastic clips. The snorkel should hang so that the mouthpiece com com fortably fortably reaches your mouth and the top is properly positioned behind your head when in use. Your instruc instruc tor wil willl show you the best best way to attach your your snorkel to your mask. To prepare your fins for use, make sure you you take any storage inserts out of the foot pocke pockets and, if you are wearing wearing heel-strap fins, adjust the straps straps around your heels for a snug, snug, comfortable fit (figure (figure 3-2). 3-2). Have your booties on when you adjust the straps. straps. Making Making the straps too too tight can can cause your feet to cramp. If the straps are too loose, loose, your kick kick will ill be
Chapter 3- Diving Skills
F IGI G U R E 3 - 1 . T H E S N O R K E L ISI S U S U A L L Y A T T A C H E D T O T H E L E F T SIDE OF YOUR M ASK STRAP.
F IGI G U R E 3 - 2 . B E S U R E T H A T Y O U R F I N S T R A P S A R E A D J U S T E D S O T H A T T H E Y A R E S N U G B U T N O T T IGIG H T .
awkward awkward and ineffici inefficient, ent, your your foot might cramp, cramp, and you might lose a fin. If your fin straps are oily oily or slippery from a lubri lubri cant used in manufactur manufacturing, ing, wash the straps straps in mild soap and water to remove the oil. oil. Leavin Leaving g the straps oily oily can cause the straps to slip in in the water and loosen your fins.
D o n n i n g Y o u r G e a r When you are ready to go diving diving,, and you have complete completed d your site survey and dive plan, plan, you don or put on most or all all of your gear at th the e dive site. site. Depending on your gear, your w wet et suit is usual usually ly the first piece of gear to put on. Sit Sit down when you don your your booties to avoid falling falling,, especially if if you are on a rocking boat. boat. Your feet and your booties must be be either completely dry or completely wet wet for the booties booties to slip on easily. Your fins must be be donned donned at the the water’s edge. If it is possible to to put your fins fins on while sitting sitting,, you wil willl be less likely likely to fall. fall. However, most most of the the time, you will ill fig have to to don don your fins while standing. Always use a fig urefou r positi position on when donning your fins as follows: 1. Steady yourself by putting one hand on your buddy’s shoulder. 2. Cross the ankle of the leg leg closest to your buddy over the knee knee of your your other leg (fig (figur ure e 3-3)-
F IGI G U R E 3 - 3 . U S E Y O U R B U D D Y F O R S U P P O R T A N D T H E F IGI G U R E F O U R P O S I T IOI O N T O D O N Y O U R F I N S .
3. Hold your your fin fin by the side side where where the blade and foot pocket meet, meet, or by the strap with with the bottom facing facing away from you. 4. Put Put your your foot in the foot pocket of the fin. 5. Slide Slide the heel strap up and over your heel. 6. Turn Turn around and and repeat the proce process for your other leg. Avoid walkin walking g more than a short distance while while you are wearing your ffins ins because you can easily easily lose your
NAUI Scuba Diver
F IGI G U R E 3 -4- 4 . I F Y O U M U S T M O V E W H E N W E A R I N G F I N S , B E S U R E T O W A LK B A C K W A R D .
m
balance and fall. If you must must mo move ve when wearing your fins out of the water, water, be sure to move by by shuffling shuffling your your feet backward or by side steppin stepping g (figu (figure re 3-4). Never try to walk forward in your fins. You might need to don your mask and snorkel snorkel last last so that you will will not restrict your vi vision sion when you are out of the water. One procedure to don your your mask is: 1. Positi Position on the mask on your face. 2. Slide Slide the strap down over the back or your head(figure (figure 3-5). 3-5). 3. Check the skirt skirt of the mask to be sure that no hair hair or part part of any suit hood hood are caught under the skirt skirt (figur (figure e 3-6). 3-6). Be sure sure that your mask strap is not too too tight. If the mask and strap are too too tight, it wil w illl not be comfortable. comfortable. If you are going in the water to snorkel, place the snorkel in your your mouth and adj adjust ust it along the strap so the snorkel fits easily in into to your mouth (figure (figure 3-7).
F IGI G U R E 3 - 5 . B E S U R E T H A T Y O U R M A S K I S P O S I T IOI O N E D COM FORTABLY ON YOUR FACE AND HEAD.
U s i n g Y o u r Fins Your fins provide provide you you with thrust and stability stability in the water. When you are fully fully equipped equipped for diving, you must must use the large muscles muscles in your legs for propulsion. Using your legs frees frees your hands to carry carry a camera and take pictures, a ligh lightt for night diving, diving, or use other items items.. You can move your fins fins in in a number of ways to cre-
F IGI G U R E 3 - 6 . B E S U R E T H A T Y O U G E T A L L Y O U R H A I R O U T O F Y O U R M A S K .
ate propulsion. The most common common kick is the flutter kick (figu (figure re 3-8). 3-8). This kick differs in many ways from a swimmer’sflutter kick. When you kick with fins, think of
Chapter 3- Diving Skills
F IGI G U R E 3 -8- 8 . Y O U R K I C K S H O U L D B E S L O W A N D W I D E A N D U S E T H E F IGI G U R E 3 7 . T H E S N O R K E L S H O U L D R E P O S I T IOI O N E D C O M F O R T A B L Y
M U S C L ES E S O F Y O U R U P P ER E R L EG EG S A N D L O W ® T O R S O .
W H E N T H E M O U T H P I E C E ISI S I N Y O U R M O U T H .
your legs as broomsticks and your fins fins as the bristles of the broom. You sweep up and down from from the hip, hip, keep ing your knees almost straight straight and your toes pointed. When kicking kicking in fins, your kick kick must be slow, deliberdeliber_ _ ate, ate, and andwide wide. If you bendyour knees toomuch much and pull I L L J your upper legs legs up towardsyour stomach, kicki kicking ng as if you are pedaling pedaling a bicycle, bicycle, your fins w will ill slip back and forth in thewater andproduce very littl little e thrust. If you kick kick too fast, you will will tire quickl quickly y and your up and down strokes will will be small andwill will not give give you much much propulsion propulsion. If youwant to move faster in the water, simply simply kick kick harder, and longer with emphasis on your your downward stroke. On the surface, modify your kick kick so that that you keep your fins in the water. water. Shorten the up stroke so so that your fin fin does not come out of the water. You can also also swimvery efficiently on your back or your side while using the the flutter flutter kick on the the surface. Swimming Swimming on on your back (figu (figure re 3-9) or side (figur (figure e 3-10) keeps your fins in the water and is is a good change change of pace from swimming face face dow down. Periodic Periodically ally check in the direc tion of travel, travel, asyou cannot cannot see ahead while while swimming swimming on your back. When you are kicki kicking ng on the surface, make sure you have just enough enough air in your your BC to make you buoy buoy ant or float. float. If you get get tired, you can stop stop kicking kicking and rest. As long as you are buoyant, you can rest without without effort for for as long as necessary.
F IGI G U R E 3 -9- 9 . M A N Y D IVI V E R S P R E F E R T O S W I M O N T H E I R B A C K S O N THE SURFACE.
RG URE 3-10. YOU CAN ALSO SW IM ON YOUR SIDE ON THE SURFACE.
NAU I Scuba Sc uba D i ver
at the surface, be sure to establish buoyancy by inflat inflating ing your vest or buoyancy compensator compensator (BC (BC)) soyour need to kick is eliminated. When replaci replacing ng a fin in the water, use the the same same fig fig ure four position you used used to don your fins. fins. This posi tion elimina eliminates tes muscle strain on the large muscles muscles in the back of your leg leg and might brin bring g your foot into position where you can see what you are doing, though this is not essential. essential. You should learn to don don and and remove gear by feel alone. alone. F IGI G U R E 3 1 1 . W H E N Y G U D U T H E D O L P H I N K ICI C K , Y O U S T A R T B Y
B r e a ttt t i i n g t h r o u g h Y o u r S n o r k e l
BENDING FORW ARD AT THE HIPS.
:
•/ :•*
■»
V 4
Breathing Breathing through your snorkel snorkel while face down in the water will will help you conserve conserve energy, energy, as well as the the air air in your cylinder. cylinder. You breathe slowly and deeply deeply when using a snorkel so you get good air transfer through through the snorkel tube. Be sure that that the end of the snorkel snorkel is positioned positioned at the back of your head to keep keep the open end out of the water. Also, remember to keep your body body in a horizon horizontal tal position when swimming at the surface.
S u r faf a c e D i v ini n g F IGI G U R E 3 1 2 . W H E N Y O U A R C H Y O U R B A C K , Y O U R L E G S R ISI S E I N T H E W A T ER ER .
You can also use the dolphin kick when diving. When doing the dolphi dolphin n kick, kick, keep your your legs together and knees relaxed relaxed and alternate alternately ly bend forward from your your hips and then a arch rch your your back back (figu (figures res 3-11 and 312). This This movement causes your body to move through the water just like a dolphin. You will ill learn learn these these and other other ways to kick kick with fins fins soyou can change kicks if if your legs get get tired. Also, Also, you will learn how to kick with one fin in case a fin strap breaks or you lose a fin. fin. If a strap on your fin works loose during a dive or pulls pulls free, free, you must be able to remove the fin, fin, correct correct the problem problem, replace replace the fin, fin, and continue with your dive. dive. It is usually usually easier to to correct correct a fin proble problem m under under water than at the surface. If you need to fix a problem
There are a number number of dives you can can use to get surface div dives es.. To under water. These These dives are called surface perform perform a good surface dive, dive, you must be weighted so you are neutra neutrally lly buoyant at the surface. The key to a successful surface surface dive is is to get as much of your body out of the water as possible. possible. The weight of your body body out of the water wi willll help push you ben beneath eath the surface of the water.
Head First There are two common headfir headfirst st dives: the pike dive and the tuck dive. The tuck dive causes less splash, and is less likel likely y to scare fish. With either either dive, you want to get your leg legs as far out of the water as possible possible in a straight, vertical vertical line. line. The weight of your legs legs carries you well well below the surface. The steps for the pike pike dive are: I. Lie horizontal at the surface. surface.
Chapter 3- Diving Skills
F IGI G U R E 3 1 3 . T H E K E Y T O A S U C C E S S F U L P IKI K E D IVI V E ISIS T O G E T A S M U C H O F Y O U R B O D Y O U T O F T H E W A T E R A S P O S S I B L E .
2. Poin Pointt your hands, palms together, together, and anns straight, at the bottom bottom or your target for the dive. 3. Bend forward at the hips hips until until the trunk of your body body is vertical vertical in the water. water. 4. Snap your legs legs up in the air until until they are in a straight line line with the rest of your body body.. 5. Kick Kick to continue continue your your descent assoon as your down ward momentum begins to decrease (f (fig igure ure 3-13). The steps for the the tuck tuck dive are: 1. Position Position yourself yourself upright upright in the water. 2. Tuck your legs to your chest in a tuck position and, at the same time, use your your hands and fins fins to rotate your body to a head down position. position. 3. Quic Quickly kly and smoothly, smoothly, extend your your arms down as you extend your legs up into the air air so your body body is in a straight vertical vertical line. line. 4. Kick Kick to continue continue your descent as soon soon as your your downward momentum begins to decrease (figure 3-14). Both dives should be carried carried out in in one smooth, continuous motion.
F IGI G U R E 3 1 4 . A T U C K D I VE V E ISIS A G O O D D IVI V E T O U S E F R O M A S T A T I O N A R Y P O S I T IOIO N .
F e e t Fipst Feet-fi Feet-first rst dive dives s are partic particula ularly rly useful for skin divers. divers. On scuba you usually usually settle gently below the sur face and continue your descent descent feet first. first. The steps for a feet-first dive are: 1. Position Position yourself yourself upright in in the water. water. 2. Hold your head upright upright and breathe through your snorkel or regulator.
F I G U R E 3 - 1 5 . A F E E T - FIF I R S T D I V E ISIS A G O O D D I V E T O U S E T O C O N T R O L Y O U R D E S C E N T A N D C L E A R YO U R E A R S .
3. Stretch your your arms out to your sides. sides. 4. Spread your legs forward and back into a split position.
NA UI Scuba Sc uba D i ver
5. Kick Kick your legs together and bring yo your ur arms forceful forcefully ly down to your sides at the same time. time. 6. Stroke your your arms up over your head as your head goes under water. 7. After you have cleared cleared your ears, tuck tuck your knees knees to your chest chest and turn turn your body soyou are are fac fac ing down. 8. Continue Continue your descent tothe bottom (figur (figure e 3-15). A feet-first dive is also called called a kelp dive. dive. There are variations to this dive dive that your instructor will w ill show show you. you.
S h a l lol o w W a t e r B l a c ko ko u t If you are free diving, before you do a surface dive, dive, you want to breathe in in and out deeply a few times before before you take in a deep breath of air air and hold your your breath to doyour dive. If you take in more than three or four breaths, you are hyperventilating excessively excessively and this this can be a problem. If you breathe in and out out deeply deeply and rapidly for more than three breaths, you lower the level of carbon dioxide (C0 (C02 2) in your your body. However, ever, the deep deep,, rapid rapid breathing cannot raise the the level of oxygen oxygen (02 (0 2) in your body body.. Mo Most st people do not realize that that it is higher levels of carbon dioxide that that gives the stimulus to breathe. breathe. When you you do your dive, you use u up p the 02in 02 in your your lungs, but do do not build up enough C02in C02 in your body to the point that that you you feel the need to breathe. breathe. This can can cause you to lose consciousn consciousness ess or black black out under water. Because you you are most most likely likely to black out at, o orr as you you near, the surface on your ascent, the problem is called called shal shallo low w water water black blackout out.. Shallow Shallow water blackout is easy to prevent. vent. Just Just breathe in and out deeply twice, and on your third third breath, do do your dive. dive. This breathing technique technique will will work without excess excessively ively lowering the the level of C02in C02in your body.
F IGI G U R E 3 - 1 6 . E X H A L I N G T H E A IRI R I N Y O U R L U N G S F O R C E F U L LYL Y C L EA R S T H E W A T E R O U T O F Y O U R S N O R K E L
and with minim minimal al effort. They are the blast clear and and displacem ent clear. clear. the displacement You can also obviously clear your snorkel at at the surface by lifting lifting your head completely out of the the water, water, removing the snorkel snorkel mouthpiece, and allow allowing ing the water to drain drain out of the snorkel. This technique technique uses uses a lot of your energy energy,, is a signal of a novice (new) (new) diver or a problem, and is not recommended.
Blast C l e a r i n g You perform perform the the blast clear by exhaling air air from your m lungs forcefull forcefully y as as you surface surface from a dive. dive. The air will will blow the the water out ofyour snorkel (figure (figure 3-16). 3-16). Take in your next breath breath cautiously cautiously in in case any water is left in the snorkel. You can breathe past water left left in the bottom bottom of your your snorkel as long as you breathe slowly. Then you blast clear again again to get rid of the the remaining water. water. Each time you take a breath following a blast clear clear you should be cautious to avoid inhali inhaling ng water. water.
D i s p l a c e m e n t Clearing Clearing Water Irom Your Snorkel Water can can enter your snorkel through through the open end from waves, waves, from accident accidentall ally y dipping the end of the snorkel in the water, and from doing a dive. dive. There are two ways ways to clear your snorkel quickly and efficiently
The displacement displacement clear clear is an alternative technique. It uses uses the least amount amount of energy and removes removes the water from your snorkel snorkel by the expansion of a very small amount of air you exhale into the snorkel as you surface(figur (figure e 3-17).
□
Chapter 3- Diving Skills
A S S E M B L I N G S C U B A E Q U I P M E N T You must know how to assemble assemble your own gear for diving. Your gear gear includes your cylinder, buoyancy compens compensator ator (BC (BC), and regulator as well as your weight weight belt. Remember Remember that as a respons responsible ible diver, no one is responsible responsible for the proper assembly and operation operation of your equipment except except you.
I.
A s s e m b l i n g Y o u r S c u b a U n i t F IGI G U R E 3 1 7 . T H E D ISI S P L A C E M E N T C L E A R R E P LAL A C E S T H E W A T E R IN THE SNORKEL WITH AIR, IN PART, BECAUSE THE A I R E X P A N D S A S Y O U A S C E N D .
You perform the displacement clear clear by using the following following step steps: 1. Til Tiltt your head back s so o you you are looking looking straight straight up when you are ready ready to ascend from your your dive. 2. Swim to the surface, keeping your head tilted tilted back. 3. Exhale Exhale slowly slowly into your snorkel as you approach the surface. The air air displaces the water as you ascend. 4. Til Tiltt your head forward to look face down into the water as your head breaks the surface. 5. Inhale. Inhale. You should should not have any water left in your snorkel.
V e r i f y What tfeu H a v e Learned Review the followin following g questions questions about using your mask, mask, snorkel, and fins: 1. If you must must walk in fins, you mu must st walk 2. To prevent losing losing your balance when donning fins, you can or _______________________
3. Two recommended methods of clear clearin ing g your snorkel are and and 4. The clear of your snorkel requires the least amount of energy. energy. _________________________
_______________________________
____________________
Your scuba scuba unit unit consists consists of your your cylinder, BC, and regulator. regulator. By using the follow following ing steps, ps, you will will soon be able to set up up your scuba unit correctly and efficiently. An instructor or divemaster divemaster can easily easily tell tell whether some some one is an an experienced diver just from the way they set set up their gear. To assemb assemble le your scuba unit unit,, use the followi following ng steps: 1. Place Place your cylinder cylinder in front of you with the on/off knob knob to your right, right, and the opening where the the air air comes out of the valve fa facing cing away from you. 2. Pu P ull the dust dust cap cap off of the scuba scuba cylinder cylinder valve and check check for the presence of the O-ring O-ring on the cylinder valve. valve. 3. Wet the tank strap of your BC if water is is easily accessible. 4. Pick Pick up your BC with the shoulder straps straps in your hands and the tank strap facing facing you. 5. Slip Slip the tank strap over the the cylinder cylinder and move it down the cylinder cylinder until until it is at the correct height. Your instructor wi willll showyou the cor rect placement placement for your BC’s tank strap (figure 3-18). If the strap is too too low, your first first stage will hit your head head during your dive. If the the stra strap p is too high, the cylinder will will be too low on on your back. This position might throw throw you off bal ance, ance, and it will will be difficu difficult lt for you to to reach your your second stage hose at the first first stage to recover a lost regulator. 6. Tighten the tank strap strap and secure it. Your instructor will will show show you the correct operation of your tank tank strap fastener. fastener.
NAU I Scuba D i ver
F IGI G U R E 3 - 1 8 . Y O U R R C M U S T B E P O S I T IOI O N E D A T T H E C O R R E C T H E IGI G H T I N R E L A T I O N T O T H E C Y L I N D E R .
□
7. Pic Pick k your BC up by the shoulder straps straps to see see if the cylinder cylinder slips in the tank strap strap (figu (figure re 319). If the cylinde cylinderr moves, oves, you must tighten the strap strap around the cylind cylinder. er. 8. Pick Pick your regulator up and turn it so that the the second stage hose extends toyour your righ rightt and, for most regulators, regulators, the gauges and low-pressure low-pressure infla inflator tor hose to your left. Make sure sure that the knurled (ridged) (ridged) knob of the yoke screw is fac ing your stomach. 9. Loosen the yoke screw and remove remove the dust cap from the first first stage. 10. Attach the regula regulator tor to the cylind cylinder er using using one of the following methods: • For a United States-made regulator, regulator, slip slip the yoke down over the cylinde cylinderr valve (figu (figure re 320). The inlet for the first stage stage will ill match up with the outlet from the cylinder valve. The inlet for for the first stag stage of the regulator regulator will will fit right into into the indentation on the cylinder cylinder valve and against th the e cylinder’s cylinder’s O-ring. -ring. Only tighten the knob knob until until it is finger tight. • For a DIN valve valve regulator, regulator, screw the the first stage stage into the the DIN valve only unt untilil it it is finger tight. 11. Tighten the yoke screw only unt untilil it is finger tight (figure (figure 3-21). Do not use force. The 0ring will will form an airtight airtight seal when when you turn on the cylinder.
F IGI G U R E 3 1 9 . B E S U R E T H A T Y O U R C Y L INI N D E R D O E S N O T S L IPI P INI N THE TANK STRAP.
F IGI G U R E 3 - 2 0 . T H E O U T L E T F R O M T H E C Y L I N D E R V A L V E M A T C H E S U P W I T H T H E I N L E T F R O M T H E F IRI R S T S T A G E W H E N Y O U H A V E T H E R E G U L A T O R P O S I T I O N E D C O R R E C T L Y .
12. Connect the low-pressure low-pressure infl infla ator tor hose from your first first stage to the the power-inflator hose hose on your BC (figure (figure 3-22). 13. Hold Hold your console so that your submersible submersible pressu pressure re gaug gauge e (SPG (SPG)) is facing away from you, you, anyone else, else, or other gear. It is is best best to point the face down down when you turn turn on your cylinder. cylinder. There is a very sligh slightt chance that the glass face of the SPG could could pop pop off, off, should the inner inner workings workings and the pressu pressure re relief relief fail. fail.
Chapter 3- Diving Skills
F IGI G U R E 3 - 2 1 . T H E Y O K E S C R E W S H O U L D O N L Y B E T IGI G H T E N E D U N T I L I T ISIS S N U G . D O N O T U S E A N Y F O R C E .
F IGI G U R E 3 - 2 3 . C H E C K T H E S U B M E R S I B L E P R E S S U R E G A U G E T O B E SURE THE CYLINDER IS FULL.
15. Open the cylind cylinder er valve completely completely by turning turning the on/off on/off knob knob counterclockwise counterclockwise unti untill it it stops. Then turn the knob back about one-quarter turn. This completes the assembly assembly of your scuba un unit. it. However, before you can use the unit, unit, you must test it to be sure it is operating operating properly.
T e s t i n g Y o u r S c u b a U n iti t F IGI G U R E 3 - 2 2 . B E S U R E T O C O N N E C T T H E L O W - P R E S S U R E ININ F L A T O R H O S E T O T H E P O W E R -I- I N F L AT AT O R H O S E O N Y O U R B C .
14. Slowly Slowly turn on the cylinder cylinder by turning turning the on/off on/off knob knob counte counterclockwis rclockwise. e. You will ill hear air pressurizing the hoses oses of the the regulator. If you hear a loud hissing hissing sound from the cylinder cylinder valve, you may have a problem with with the seal betwe between en the the cylinder cylinder valve and the first first stage. This indicates that the valve valve O-ring needs eeds to be be replaced. replaced. Air leaks elsewhe elsewhere indicate indicate other problems that must be be corrected before diving. diving.
Testing Testing your scuba unit includes making sure that your prim primary ary and back-up back-up second second stages work and that m your BC is infla inflating ting and deflating properly. The steps to test your scuba unit are: 1. Look at your SPG to see how much air air you have in your cylinder cylinder (figure (figure 3-23). If you are using using a 200 bar (3000 (3000 psi) cylinder, your your SPG should reflect reflect about 200bar (3000 psi). If your gauge reads less than about 165 bar (2500 psi), psi), you should switch your equipment equipment to another cylinder, if you are planning a normal full-length dive. 2. Put Put your primary regulator regulator in your mouth, breathe out, and then breathe in to be be sure sure that
NAU I Scuba D i ver
F IGI G U R E 3 2 5 . O N E W A Y T O S E C U R E Y O U R E Q U I P M E N T I S T O L A Y T H E C Y L ININ D E R O N I T S S IDI D E IFIF YO YO U W O N T B E U S I N G I T I M M E D I A T E LYL Y . F IGI G U R E 3 2 4 . C H E C K Y O U R P R I M A R Y A N D B A C K - U P R E G U L A T O R S T O B E S U R E T H E Y A R E D E L I V E R INI N G A I R O N D E M A N D .
the regulator is delivering air air on demand demand (figure (figure 3-24). Do not forget and breathe breathe out first, first, as you might inhal inhale e debris, sand, or small pebbles. pebbles. Even insects have have been found in regulator regulator second stages after after storage. 3. Repeat the process in step 2 with with your your back-up or alternate air air source regulator. regulator. 4. Press your power-inflator power-inflator button to be sure that air is flowing into yo your ur BC on dema demand nd.. 5. Press your deflator/oral deflator/oral infl inflat ator or valve button to be sure that air air flows out of your BC on demand. When you have finishe finished d assembling your gear, you must make sure that the unit unit is is secured and not in da dan n ger of fallin falling g over and injur injuring ing you or someone else else or damaging the cylinder cylinder valve or regulator. If you are on a boat, place the unit unit back in the cylinder cylinder rack rack and secure the cylinder cylinder with the supplied elastic elastic or other tie cord. If you are beside a pool, place your second stages and gauges inside the BC and lay lay the cylind cylinder er down on the tank strap strap (figure (figure 3-25). If you are on a sandy beach, push the tank bottom deeply into into the sand to make a secure base and wrap your hoses around the valve.
Howyou set up your weight belt is is important important because because it affects your comfort and safety. safety. You want to have the correct correct amount of weight, and you want the weights to be balanced balanced on the belt. With With train training ing and experience, you w wililll know how how much weight you need need to wear based based on the diving diving suit suit you are wearing. wearing. As a new diver, diver, your instructor will will help you determine determine how much weight you should wear. A rule of thumb for the the amount of weight an average size person person needs eds in salt water with a full full 7 mm (1/4 inch) inch) wetsuit is 10% 10% of your body weight plus 2 kg (5 lbs). lbs). The length of your belt is also important. important. The excess cess tail tail of the belt that hangs out of the buckle must be long enough for you to grab it with your your entire entire hand, and only that long. If you are are using using a flat 5 cm (2 inch) inch) wide nylon nylon web belt, with no elas elastic, tic, and blockweights, blockweights, string string the weights on your belt using using the following following procedure: 1. Lay Lay the weight belt out straight on a flat flat surface with the buckle facing up. 2. Brin Bring g the end of the the weight belt up through a slit slit in the first weight and down down through the other slit. 3. Position Position the weight so so it will will be over over or slightly slightly
Chapter 3- Diving Skills
forward of your hip. 4. Repeat the process in steps 2 and 3 unti untill you have all all the weights strung on the the belt. 5. Try Try the belt on to see the position position of the weights. Be sure that you distribute distribute the weights evenly on IL jL J each side and leave the area of the belt that spans spans your middle back cl clear ear of weight weights. s. To keep the weights weights from shifting shifting,, you can put weight keepers, which which are metal or or plastic clips, clips, between the slits in in the weight to keep the weights weights from sliding. sliding. You can also put a twist in the belt as you thread it through your last last weight to keep keep the the weights from slid slid ing off the belt. belt. Ask Ask your instruct instructor or for tips to keep keep your weights securely positioned on the weight belt. If you are using soft weight weights s in a weight belt with pocke pockets, distribute distribute the weights evenly throughout the belt. If you have too mu much ch weight on one side and not not enough on the other, other, you wil willl not be able to easily easily stay in control in the water. water. The weights weights will keep pulling pulling you to one side.
on a moving boat. boat. You usually usually don the bottom bottom of your m suit first, first, followed by your booties. oties. The bottom bottoms of the legs ofyour diving diving suit suit should then go over over the outside outside of your your booties. You don the hood and then the jacket. The hood hood tucks tucks into the jacket of your diving diving suit. If the weather is warm, you you want to be sure to set up your scuba un unit it and weight weight belt before donning your diving suit. If the weather weather is cold, you might want to don the diving suit first first before you set up your scuba. If you get get too warm with your suit suit on, be sure to cool yourself yourself down by getting in the water or pouring cool water over your head and suit.
CB C O ■
So"
D o n n i n g Y o u r S c u b a U n i t A buddy pair pair must don don scuba units as a team (fig (fig ure 3-26 3-26). ). It is easier to don scuba gear when you work IT ^ l together together beacause beacause of the extra hands that that are availa available ble to position position hoses and straps.
DONNING SCUBA GEAR There is a specific order to donning all all of your scuba gear beforeyou get in the water. Your instruc instructor tor will ill show you the way they want you to don your gear. gear. One order order is as follows. For obvious reasons, reasons, your diving diving suit must beput on first. first. Your scuba unit unit is next, fol fol lowed lowed by by your weight belt. belt. And And final finally ly your mask and and fins. Putting Putting your gear on on in this order makes the proces process easy and fast, and ensures ensures that that your your weight belt belt can be readily ditched, if if necessary. necessary.
D o n n i n g Y o u r D i v ini n g S u i t Depending Depending on where you learn learn to dive, you might might use anything anything from a dive skin to a dry suit. There are different specific specific procedures procedures for donning ea each ch type of diving suit. Your instructor wi willll show show you the prope proper techniques techniques for the suit you w wililll be using. No matter which which type of suit you are wearin wearing, g, be sure you sit down down when donning the b bottom ottomportion. portion. This This is especially important if you are donning your diving diving suit
F IGI G U R E 3 2 6 . Y O U A N D Y O U R R U D D Y A LW LW A Y S D O N Y O U R S C U B A U N IT S A S A T E A M .
59
MAUI Scuba Diver
F IGI G U R E 3 2 7 . B E S U R E T H A T YO YO U R B A C K - U P R E G U L A T O R A N O GAUGES ARE CLIPPEO TO YOUR BC.
To donyour scuba unit unit while while standing, standing, use the following procedure: 1. Stand your cylinder cylinder upright upright and face your BC towards you. 2. Grasp your BC by the shoulders as your your buddy grasps the scuba unit unit by the first first stage and the bottom bottom of the cylinder. cylinder. 3. Lift Lift the cylinder cylinder together with one smooth smooth motion and help your buddy buddy steady steady the cylinder cylinder on his/her thigh. 4. Put your arms through the armholes. 5. Fasten your waistband and clips. 6. Let your your buddy know you are are ready ready to support the weight of the cylinder cylinder so they can llet et go. 7. Secure your back-up regulato regulatorr and gauges gauges to the front of your BC (f (figur igure e 3-27). 8. Repeat the the process so your your buddy can don their BC. After you have both donned your gear, check check to be sure that your shoulder straps are comfortably posi tioned. The cylinder cylinder should feel secure on your back. Also, Also, if if your weight belt is already already in place, place, be sure sure that the buckle of your weight belt and the free end end of your weight belt can be easily reached without without obstructions.
A N D T H E N S T E P O V E R IT .
Donning Your Weight Bel! One way to don your weight belt belt is to use the foll follow ow ing procedure procedure if your dominant hand is your right hand: hand: 1. Hold the buckle of the weight belt in your left hand hand and the free en end d of the belt in your your right hand. 2. Step over the belt with with both legs (figu (figure re 3-28). 3. Slid Slide e the belt up your legs and over over your hips. 4. Bend over and let y your our back back support the weight of your belt. 5. Slid Slide e the free end of the belt through the buckle buckle and fasten the belt securely around your waist. If your left hand is your dominant hand, you can use use the previous procedure procedure with your left hand hand holding holding the free end end of the weight belt so that your dominant dominant hand will ill open the quick release release buckle. Always be sure to pick pick up a weight weight belt by the free end, end, which which is the end end without the buckl buckle, e, to prevent prevent the weights from sliding sliding off the belt. It is best to to secure ly fasten your weights on your own belt to further further pre vent this possibility.
Ch apter 3- Divi Di ving ng Sk ills ills
V e r i l y W h a t Y o u H a v e L e a r n e d Review the following following questions questions about assembling your scuba gear: 5. Howshould your regulator be oriented when when you mount it on your cylinder?
6. A scuba cylinder valve valve is turned on when you rotate it in in a direction. 7. How should you and your your buddy don your scuba units? ___________________
8. To ensure that it is clear to beditched if necessary, you should put the weight bel beltt on
F IGI G U R E 3 2 9 . 0 0 A G O O D E Q U I P M E N T I N S P E C T I O N B E F O R E Y O U A - l
G E T I N T H E W A T E R . Y O U M U S T B E F A M I L I A R W IT H
- J
Y O U R B U D D Y ' S G EA EA R .
_____________________________
ENTERING AND EXITING THE WATER Because you will will be diving diving at many different different sites, you must know know different ways of getting in and out of the water. There are general general rules that apply apply to all all entries and some rules that that are specific specific to each type of entry. You You will will beco becom me famili familiar ar with with a number number of entries entries during your confined-water and openwater openwater trainin training. g. Your instructor wi willll also teach you you specific techniques techniques for your local divin diving g area. This section of of the book introduces introduces some of the common entries entries and exits that divers use. It would take an entire entire book book to to describe all all of the entry and exit tech niques used used worldwide. You will ill learn learn local local methods thods from your instructor. instructor. Never Never assume that you know ho how w to enter and exit the water water everywhere. Always get an orientation from a NAUI diving professional to the diving diving procedures for every new site and region.
C h e c k i n s Y o u r E q u i p m e n t Onceyou and your your buddy have your equipment equipment on, you must check one another’s another’s equipment equipment one last time
before before getting in the water (figure (figure 3-29). 3-29). You must know how your buddy’s equipment works works and they must know how to operate yours in case of an emergency. The acronym, SEABAG, is an an easy way to remember remember the series series of step steps that you follo follow w to plan a dive and check each other’s equipment. SEABAG stands stands for: • Site surv survey ey • Emergen Emergency cy planning • Activity planning planning • Buoyan Buoyancy cy • Air
• Gear and and go See Chapter 6 for the steps for site site survey, emer gency planning, planning, and activity planning. planning. The steps teps for buoyancy, air, air, and gear and go are covered covered in this sec tion. tion. A checklist checklist for the steps is included included in Append Appendix ix C. To check for buoyancy, use the follo followi wing ng steps: 1. Check your your own and your your buddy’s buddy’s weight weight system to be sure that you can easily easily release the weights, weights, if necessary. Note the type of system they are wearing wearing and the type and direction of release. 2. Check Check your own and and your buddy’s BC to be sure that you know how how to power inflate, inflate, orally orally inflate inflate,, and deflate the BCs. Also note the num ber and types of releases on the BC.
NAU I Scuba D i ver
G O
To check for air, use the follo followin wing g steps: 1. Check to be be sure that your your buddy’s buddy’s and your cylinder valve is almost fully fully open open and only back 1/4 turn turn.. 2. Check that your buddy’s and your primary primary regu lator and back back-up -up regular regular are delivering delivering air air on demand. demand. Remember Remember to exhale before before inhali inhaling. ng. 3. Check that your buddy’s and your SPG reflect that the cylinder is full while breathing from the second stage. 4. Check that all all cylinder cylinders s are secure secure in their tank straps. go, use the follo To check for gear and go, followin wing g steps: 1. Check that you both have your mask, mask, snorkel, and fins ready ready to don. 2. Check that your hoses hoses are free, not tangled, and properly secured. 3. Check to be sure that that you both have have any any necessary necessary accessory accessory equipment such as lights lights or cameras. 4. Proceed Proceed to your entry entry point. No matter how experienced experienced and skilled a diver diver you become, you always always want to have your buddy inspect your equipment and be sure sure that you inspect your buddy’s equipmen equipment in addition addition to self-checks. cks. It is much easier to correct a problembefore you get in the water.
B o a t a nd nd Platform E n t r i e s There are general rules that apply apply to most most boat and platform entries: • Your BC should be part partia ialllly y inflate inflated d to provide buoyancy. • You You should hold your mask mask firmly firmly in in place to avoid flooding it or having it come off. • You should breath breathe e from your regulator regulator during during the entry. • You You should make sure that the entry area area below you is clear clear and sufficie sufficiently ntly deep deep for the type type of entry you are using. The only objective for an entry is to get into the water with with minim minimal al effort effort and effect effect on both you and your equipment. equipment. Any entry that accomplishes this objective objective is a good entry.
82
F IGI G U R E 3 3 0 . Y O U U S U A L L Y D O A G IAI A N T S T R I D E E N T R Y F R O M A LARGE BOAT.
S i a n t S t r idi d e E n t r y You can use the giant stride entry entry from a boat or dock where where the distance to the water is is no more than about 2 meters meters (6 feet) (figure (figure 3-30). This entry entry keeps you near the surface. It is appropriate whe when n the water is deeper than than 2 meters (6 feet) feet),, there are no objects under water that you might strike strike while entering, and you want want to stay on the su surface. rface. The steps steps to a giant giant stride entry entry are: 1. Have your fins on and your mask and regulator in place. place. 2. Place Place your fin fin blades blades and the balls of your feet off the edge of the platform. platform. 3. Look Look at the water below you to ensure that there are no divers below you. you. 4. Hold your mask and regulator regulator with one hand and any loo loose se items with your other hand and arm. 5. Step out from the platform platform with with one bold stride. As you step out, your trailing leg will follow behind you. 6. Bri Bring ng your your legs together together once you are under water to propel you back back to the surface. 7. Quickly check that all all your gear is still in place once you resurface.
Ch apter 3- Diving Diving Sk ills ills
C O
F IGI G U R E 3 - 3 1 . Y O U D O A B A C K R O L L E N T R Y F R O M A S M A L L B O A T.T .
8. Turn back to the boat or platform platform and signal signal to the divemaster that you are okay. Do not signal that you are okay until until you know that you are. 9. Swim clear clear of the entry are area a so the next diver can enter the water. The key to doing a good giant-stride entry entry is to be in the steppin stepping position (one leg leg behind you and the trunk of your body upright) upright) as you enter the water. Then, as you go under water, water, bring bring your your legs together to propel yourself back to the surface. Avariation variation to this entry involves putting your feet together together before you hit hit the water. This wil willl take you deeper, and can be used in speci special al cases where you do not wish to to resurface resurface immediately. immediately. This variation variation can also place less less strain on the legs legs if you enter from a height greater than about 2 meters meters (6 feet). feet).
Back Roll En try m
You use the back roll entry entry when a boat is so small that if if you stood to enter the water water you could could injur injure e yourself by fallin falling g or fall fall out of the the boat boat (figure (figure 3-31). This entry entry is also used used if you are entering the water from the side of a boat with high gunwales. gunwales. The steps to a back roll roll entry entry are: 1. Have your fins on and your mask and regulator regulator in place. 2. Seat yourself yourself with your your back facing facing the water and your rear rear end parti partial ally ly over the the edge. 3. Look behind you at the water below to ensure that that there are no obstacles or divers below you.
F IGI G U R E 3 -3- 3 2 . T H E S E A T ED E D S IDI D E E N T R Y I S E A S Y A N D C O N T R O L L E D .
4. Hold your mask and regulator regulator with one hand hand and your weight belt and any any loose items with your other hand and arm. 5. Lift Lift your your legs and let the weight of your cylinder roll roll you into the water. Your body should be in an “L” shap shape e with your legs straight. Maintain Maintain an “L” shape as you you are going into the water, or tuck your your legs to your chest. chest. 6. As you go under water, water, swim swim away away from the boat or platform platform and back back to the the surface. 7. Be sure to turn back to the boat or platform and signal signal to the divemaster that you are okay, okay, if appropriate. 8. Swim clear clear of the entry area so the the next diver can enter the water, if if appropriate. You might experience some some dizziness as you rol rolll into into the water. This results from upending upending or agitating agitating the fluids in your inner ears as as you you turn. turn. You will will reorient reorient in a few seconds. Also, be sure to recheck yo your ur mask strap, becaus because e it has a tendency tendency to slip off your head during this type of entry.
S e a l e d S i d e E n t ry You can can use the seated seated side entry entry from the side of a swimming pool, a ledge at water level in in a quarry, or from a boat dock (figure (figure 3-32 3-32). ). This is a good good entry whenever whenever you you can sit at the water’s edg edge, make your final final preparations, and then lower yourself into the water. water. The steps for a seated side entry are: 1. Sit Sit at the edge of thewater with your your legs in the water.
NAUI Scuba D i ver
2. Don your fins fins and mask and put your regulator regulator in your mouth. 3. Place Place both of your hands on the same side of the entry edge and turn and and lower yourself yourself into the water. You should perform this step step in one continuous movement. The seated seated side entry is simple, simple, easy, and effect effective. ive. You are close to the water so the the impact impact of your entry is mini minima mal.l. Also, because you are seated, you are not as as likely likely to lose your balance as you are when standing.
B e a c h E n t r iei e s Beach or shore entries can be very different different depend depend ing on your location. They can range range from wading into calm water to climbin climbing g down rocks to get to the water’s edge. Each Each type of entry entry takes some precautions precautions..
C a lml m W a tet e r
m
When you you can walk walk into shallow, calm calm water to begin your dive (figu (figure re 3-33), it is usu usuall ally y an easy entry, but some precautions precautions are necessary: • Shuffle Shuffle your feet along sandy bottom bottoms, rather rather than stepping. This This detects holes and rocks or obstructions, obstructions, helps prevent loss loss of balance, balance, and chases chases bottom-dwelling animals animals from from your path. • Step Step carefully carefully along rocky bottom bottoms. s. Rocks can be covered with algae, whic which h makes them them slippery. Be sure to have solid footing and maintain your balanc balance e as you take each step. step. • Don your fins fins when you get to waist-deep water. If necessa necessary, ry, inflate inflate your BC and float on your back while while donning your fins. Lie down and begin swimming swimming as soon as possible. • If you lose lose your balance during the entry, entry, do not not try to stand up again. Crawl forward on your hands and knees and begin swimming rather rather than using using your energy to try and stand again.
Surl Entries through through surf require special training. If your train training ing does not include entries through surf, you
F IGI G U R E 3 3 3 . W A D INI N G E N T R I E S A R E E A S Y W R E N T H E C O N D I T IOI O N S A R E C A L M .
should receive receive additional additional traini training ng before you dive in an area with surf. Some precautions for surf entries include: • All of your equipment must must be securely in in place. • You You must watch the waves waves continu continuall ally. y. • You must time your entry to coincide with with a low low point point in the wave action. • As a wave approaches, iiff you are not yet in water water deep enough to swim, swim, keep your knees bent and duck duck under the wave as it passes. • Avoid stopping in the surf surf zone. As you approach thigh-d thigh-deep eep water, water, or if if a wave is going to break over you, have your regu regulator lator in in your mouth and and go underwater underwater into into the base of the wave. Your BC BC must be deflated when when doing a surf entry entry so you can easily get under water. water. If you are using a float, it must be traile trailed d behind you.
Rock Jetties or Breakwaters Steep rock entries entries from jetties jetties or breakwaters also require some special traini training ng and considerations. Depending Depending on your comfort level moving about in full full gear, gear, you might use a procedu procedure re simila similarr to the following to get in the water water only if if it it is calm calm without without surge or surf: 1. Find Find a rock at the water’s edg edge e that will will be good to sit on to don your mask and then push off into into the water.
Chapter 3- Diving Skills
2. You and your bud buddy dy carry carry your scuba units units and weight belts down close to the entry rock rock near the water’ water’s s edge. 3. One buddy dons their their mask and and pushes off off into the water. They then then roll roll onto their back and don don their fins. Donning your fins after leaving the rocks avoids avoids the the possibility possibility of having having a fin get stuck in the rocks and twisting or breaking breaking an ankle. 4. The other other buddy passes the first first buddy their their scuba unit unit to don and then the weight belt belt to don. 5. The buddy on land land then passes passes their their scuba uni unitt and weight belt belt to the buddy in the water to hold while while they get in the water. 6. Once the second buddy is in in the water, they don their gear and start the dive. dive. If both both buddies prefer, or if if surge is washing over the jetty, they can don their gear at their their set-up point and then climb down the rocks and into the water. Howe However, ver, you you must be careful careful to maintai maintain n your balance balance and move slowly.
Boat and Platform Exits Procedures Procedures for getting out of the water and back onto a boat boat or platform vary, vary, depending on the situa tion. You might climb climb up a ladder into a boat or onto a platform or have to take take your gear off in the water and then push yourself yourself up onto a platfo platform. rm. Some general rules apply to all all boat and platform platform exits: • Evaluate Evaluate the exit area before getting out of the the water. Conditions can change during during a dive. dive. • Make sure sure all all of your equipment is in place place and is secure as you approach approach the exit. • Think Think out the steps of your exit in in advance. advance. • Keep your fins fins in in place place as long as you are in in the water.
Ladder If a dive boat has a ladder, ladder, you might might be asked asked to climb the ladder with your scuba un unit it and weight belt in place. Use the followi following ng steps when using a ladde ladderr to exit from the water:
1. Stay Stay to one one side of the the ladder or the other unt untilil it is your turn to exit. Never get under another diver trying to exit. 2. Swim to the ladder when it is your your turn. 3. Hold on to the ladder and and use the figure four position to remo move ve your fins. If possible, possible, climb out of the water before removing the fins. fins. 4. Slip Slip your your fin straps straps over over your wrists wrists or hand your fins up to the divemaster. divemaster. 5. Plac Place e your your feet on the the bottom rung of the ladder and stand up. 6. Climb Climb the ladder ladder one step at a time, time, being being sure to maintain maintain your balance and suppo support rt the weight weight of your scuba unit. 7. Take your fins fins from the divemast divemaster er and move away from the exit area. Always remember to stay away from from the ladder ladder when someone is using the ladder. If theyfall fall,, you could be seri ously injured, especially if if they are wearing their cylinder. cylinder. It might also be possible possible in some situations situations to also remove your weight belt and scuba unit unit at at the exit point. Observe, listen, listen, and ask the divemaster for the procedure they want you to use.
B o a t T r a n s o m P l a tft f o r m You must must coordinate your approach to a swim plat plat form with the wave action. The water movement will ill help lift lift you onto the swim swim platform. platform. Sometimes Sometimes you can use the the followin following g stepswhen exiting exiting the water onto a swim platform: 1. Hand any items you are carr carryin ying g up to the the divemaster (figure (figure 3-34). 3-34). 2. Remove your weight belt and hand hand it it up to the divemaster. 3. Remove your scuba unit unit and let the divemaster pull pull it out of the water. water. 4. Place Place your hands, shoulder-w shoulder-width idth apart, on the swim platform. 5. Kick Kick your legs together together and push push up with your arms at the same time to bring bring your your body out of the water. 6. Swivel Swivel around and sit on the swim platform. 7. Remove your fins using the figure ffour our position.
NAU I Scuba Sc uba D i ver
Surf When you are exi exiting ting through surf, you must concen trate on your exit procedures. Keepyour regulator in in your mouth. Hold your mask on. Never stop in the surf zone. If the surf is rough, swim until until you can crawl crawl out of thewater on your your hands and knees (figure (figure 3-35). Once you are are clea clearr of the water, you can rol rolll over and removeyour fins.
Rock Jetties or Breakwaters F IGI G U R E 3 -3- 3 4 . W H E N Y O U E X I T O N T O A S W I M P L A T F O R M , I T I S EASIER TO HAND YOUR GEAR UP FIRST.
With With rock rock exits, exits, you reverse reverse your entry pro procedure cedure.. If If you put your gear on in the water, water, you need to to take it off in the water and hand it out to your buddy. buddy. When approa approaching ching the rock rock you are are going to use use to exit, use the wave wave action action so that the water moveme movement nt will will help you get onto the exit area.
V e r i f y W h a t Y o u H a v e L e a r n e d Review the followi following ng questions about entries entries and exits: 9. Which Which pieces of equipment equipment must you check check beforeyou get in the water? F IGI G U R E 3 3 5 . I T I S S O M E T I M E S N E C E S S A R Y T O C R A W L O U T O F T H E W A T ER E R T H R O U G H S U R F.F .
8. Leave the swim platfo platform rm area. An alternativ alternative e method is to leave all of your gear in place, remove your fins, fins, and climb up a ladder and onto the deck.
Beach Exits Procedures for beach exits vary greatly depending depending on the situation and the the conditions. You must evaluate evaluate the condition condition of the exit area and the step steps of your exit before you proceed with with your your exit.
C a iri r n W a t e r When you do do a beach exit in calm water, water, swim towards shore until until you are about waist waist deep. Stand Stand up and useyour buddy’s shoulder and the figure four posi tion to remove remove your fins. Walk Walk out of the water.
10. Three general rules that apply to entries are:
11. The objective of an entry entry is to
12. State State one example of when it is appropriate appropriate to use each of the following following entries: a. Giant Giant stride b. Back roll c. Seated
Ch apter 3- Diving Diving Sk ills ills
M A S K S K I L LS LS There are a number of ways that water can get in your mask mask during your dive. dive. For example: example: • Your mask fogs whil while e under water. The easiest way to remove the fog is to let water into your your mask and swish it around. • You You laugh laugh or smile under water, whic which h causes the muscles muscles of your face to create channels that that will will let water into your your mask. • Your mask gets knocked to the side by the careless careless movement of another another diver. In any of thesesituations, situations, you need to know how to get thewater out ofyour mask and feel comfortable doing doing it. If you are skin divi diving ng and water get gets into your mask, you can wa wait it to get back to the surface to pour the water out. out. You can also easily easily clear clear your mask under water while skin or scuba diving. diving.
co F IGI G U R E 3 - 3 6 . T H E A IRIR Y O U B R E A T H E O U T Y O U R N O S E R E P L A C E S T H E W A T ER I N Y O U R M A S K .
C l e a r ini n g W a t e r frf r o m Y o u r M a s k
m
m
To clear water from your mask or replace your mask underwate underwater, you must replace the water in the maskwith air. air. When you exhale air air into into the mask, mask, the air rises to the top and the water flows out the bottom bottom (figure (figure 3-36). Replac Replacing ing the mask underwater is the the same process as on land. land. The steps to cleari clearing ng water from your mask are: 1. Poin Pointt your chin chin toward the bottom bottom whenever you have water in your mask to prevent water water from getting up your your nose. 2. Inhale Inhale a breath of air air if if your lungs are empty and you are on scuba. 3. Put Put your finger finger tips on top ofthe maskframe and push in to mainta maintain in the seal at the top of the the mask. 4. Start exhaling exhaling through your nose. nose. As you exhale, tip your head head back slowly slowly.. The air will w ill force the water out out of the bottom of the mask. 5. If If you have a purge valve in your your mask, do not tip your head back, look toward the bottom, and simply exhale into the mask. mask. When you you are breathing breathing from scuba, you must per form the ste steps to clearing clearing your your mask deliberately deliberately and slowly (figure (figure 3-37). You must consciously think think about
F IGI G U R E 3 3 7 . C L E A R I N G W A T E R F R O M A M A S K I S S O M E T H I N G E V E R Y D I V ER ER M U S T B E A B L E T O 0 0 .
what you are doing and you must concentrate concentrate on inhal inhal ing through your mouth and exhaling through your your nose. nose. This pattern is different different from normal breathing breathing
GO
NAU I Scuba S cuba D i ver
and is different fro from m the normal normal pattern of breathing on scuba. scuba. If you do not concentrate on what you are doing, you might forget and inhale inhale water through your nose, nose, which which wil willl cause you you to choke and cough. cough. A single, single, sustained exhalat exhalation ion is more effective than than short or strong bursts of air. It does not take much air air to clear clear a mask completely. When you becom become profi cient at mask clearing, you will will be able able to clear clear your mask mask several times on a single breath of air. air. Removing water from your mask is an important diving skill. You must must repeat repeat this skill until until you are are completely comfortable with iitt and can do do it automat automati i cally. Initia Initially, lly, your instruct instructor or will will have have you you practi practice ce this skill skill in in shallow water and then will will have you you repeat repeat the skill skill in deeperwater.
R e m o v i n g a n d R e p l a c i n g Y o u p M a s k You might wonder why you would want to take your mask off under water. Generally, Generally, you don’t, but some some one else might inadvert inadvertently ently remove remove it for you. Your mask can be bumped and dislodged, or it can catch catch on something and be pulled pulled free. In these cases, you must be able able to calmly calmly locate your mask and put it back on. Your vision without without a mask mask will will not be be good good, but you will ill be able to see. Leam to open your eyes without without a mask on, because because they are more useful than you might think. When you are wearing contact contact lenses, lenses, you run the risk of of losing the the lenses if your your mask floods floods or comes comes off your face under water. In this situatio situation, n, keepyour your eyes closed unless you you need to see to locate your mask. If your mask is lost, you will ill have to rely rely on your buddy to find it it or help you surface, to avoid losing your lenses. lenses. One way to replace your your mask under wate waterr is to use use the following steps: 1. Orient Orient your mask so that the inside of the mask is facing facing you and your snorkel is on the side side on which you wear it. 2. Positio Position n the mask over your eyes and nose and place the mask strap on the back of your head. 3. Run Run a finger around around the mask mask seal and make make sure that all all of your hair hair or your hoo hood d (if (if you are wearing wearing one) is out of the mask. mask.
4. Clear Clear the water from your mask as described described in on page 67. Clearing Water Waterfrom. Your Mask on
V e r i f y W h a t Y o u H a v e L e a r n e d Review the following following question questions s about about mask skills: 13. What What are the recommended steps to replac replacing ing your mask under water?
14. Which Which way should you tilt your head when clearing clearing water from a mask with a purge purge valve?
REGULATOR SKILLS Learning Learning to scuba scuba dive dive includes more than ju just learning how to breathe from a regulator. You can do that already! Some Some of the regulator skills you will will master master during your NAU NAUII Scuba Diver certification course include: • Breathing undeiwater undeiwater if your mask mask com comes off your face. face. • Finding Finding your regulator if it comes comes out ofyour mouth while you are swimming under water. • Sharing air air with another another diver diver.. • Breathing Breathing from a free-flowing free-flowing regulator.
B r e a tht h ini n g U n d e r W a t e r When you breathe on scuba, you do all of your breathin breathing g through your mouth. However, you must exhale small amounts amounts of air into your mask as you descend to prevent mask squeezes. You must always always remember remember to kee keep p breathing breathing so that you w wililll not trap expanding expanding air air in your lungs during an ascent.
Chapter 3 Diving Shills
"
00731335
a H o o d e d Mask o r w ith o u t o M a s k
If you lose lose your mask mask under water, water, or if your mask floods, you must concentrate on your breathing breathing and maintain maintain air air pressu pressure in your nose nose to avoid avoid inhalin inhaling g water through your nose until until you correct the problem. You must must be able to do this without without needing to hold your nose closed closed, because because in many many situations, situations, you will will needto use both your your hands for other purposes. purposes.
C l e a r i n g Y o u r R e g u l a t o r □
Whenever the mouthpiece mouthpiece of your regu regulator lator is out of your mouth, mouth, you must must continua continually lly exhale a small stream stream of bubbles (figur (figure e 3-38). This helps keep your airwa airway y open. You do not want to lock off yow yow throat. throat. If you do rise in the water, water, the air in your lungs will will expand, and the air air must be able to escape escape through your mouth instead of over expanding your lungs and causing causing damage. Your regulator sh should ould remain in your mouth as much as possible, ossible, but there are a few situations situations in which which you must remove it. If the mouthpiece of your regulator regulator comes out of your mouth for any reason, the reg regulato ulatorr second second stage stage will automatically automatically fill fill with water. water. When you put the the reg ulator ulator back in your mouth, you must must be be able to clear the water from the second stage before you can can breathe. There are two primary primary ways to clear your your regulator regulator sec ond stage of water: the blast clear clear and the purge purge clear.
F IGI G U R E 3 3 8 . Y O U M U S T E X H A L E A S M A L L S T R E A M O F B U B B LEL E S W H E N E V E R T H E R EG E G U L A T O R ISI S O U T O F Y O U R M O U T H .
P u r g e Clear If you do not not have enough enough air air in in your lungs to per clear to form the blast clea clear, r, you can use the purge clear to get the water out of your second stage stage. To perform the purge clear, clear, use the followin following g steps: 1. Put Put your your tongue up to the roof of your mouth and against against your teeth to prevent water from from the sec ond stage from going into into your mouth and throat. 2. Lig Lightl htly y press the purge purge button located on the front front or side of the second stage to replace the water in your second second stage stage with with air air from your cylinder.
R e c o v e r i n g Y o u r R e g u l a t o r B l a s t Clear The quickest and easiest way to removewater from the secondstage ofyour your regul regulator ator is to do theblast clear. The blast clear is not tru truly ly a blast of air, air, just a simple exhalation. exhalation. To perform the blast clear, you put the regula tor mouthpiece outhpiece in your mouth and exhale the air remain remain ing in your lungs out ofyour mouth. mouth. The air air from your lungs forces the water out of the one-way exhaust valve located on the bottom or side of your your second stage. Most regulators regulators require that you be in an upright position or facing slightly slightly down to clear all all thewater out of the sec ond stage. Some regulators requi require re you to tilt tilt to the side side oppositetire hose to full fully y clear clear the the regulator.
There will will be times when your second second stage will ill be out of your mouth during a dive. For example, if you are diving diving in kelp, the kelp might wrap around your hose hose and it might be convenient convenient to take take the regula regula tor out of your mouth to untangle untangle it. Also, Also, you might get get so relaxed that you forget to bite on yo your ur mouthpiece to hold the regulator iin n your mouth. There are two ways to recover your regula regulator tor:: the sweep method and the reach reach method.
Sweep Method Use the following following steps steps to find your regulat regulator or using sweep p meth method od'. '. the swee
NA UI Scuba Sc uba D i ver
1. Get into a vertica verticall position, right right side down or lean to the right. 2. Bring Bring your your right right elbow into your side. 3. Touch your right right hand to your thi thigh gh and then move it back to touch your cylinder cylinder.. 4. Sweep eep your right right arm out from your cylinder cylinder in a big circle circle around around to the front front of your body. Your primary primary regulator regulator should be in the bend bend of your arm (fi (figu gure re 3-39)5. Put Put your primary regulator in your mouth mouth and either blast or purge clear clear the second second stage. Always remember remember to blow a steady stream of small small bubbles whenever the regulator regulator is is out of your mouth.
Reach Method Use the following following steps to find your your regulator regulator using the reach method : 1. Reach over your right shoulder with your right right hand and grasp the first stage of your regulator. It might be necess necessary ary to lift your cylinder cylinder by its boot from the bottom with your left hand. 2. Feel for the primary primary regulator regulator hose on the upper or front right right side of your first stage (figure (figure 3-40). 3. Follow Follow the hose hose down to the end. Your prima primary ry regulator regulator will will be at the end end of the hose. 4. Put Put your regulator in your mouth and either blast blast or purge clear clear the the second stage. Remember, if if you happen to recover your back-up second second stage or cannot immedi immediately ately locate your your primary primary second stage, you can can always use your own back-up reg ulator or redundant scuba system for breathing until you find your prim primary ary second second stage. Use Use the alternate air air source source only until until you can find your primary regula regula tor or you can get your buddy’s attention and assistance to locate your primary regulator. regulator.
B r e a t h ini n g f ror o m a F r e e - F l o w i n g R e g u l a t o r When a regulator begins begins delivering air air continuously, flowing (fig it is freeflowing (figure ure 3-41). To stop the freeflow, turn turn the regulato regulatorr so the mouthpiece opening opening is down. Fortunately, this this is about the only problemyou will will ever have with a regulator, and it is is usually usually not serious serious..
F IGI G U R E 3 - 4 0 . F E E L INI N G O V E R Y O U R R I G H T S H O U L D E R W I T H Y O U R R IGI G H T H A N D F O R Y O U R R E G U L A T O R H O S E I S O N E WAY TO FIND YOUR REGULATOR.
However, you should should not dive with with a free-flowing regulator. If the regulator starts to flow continuously during your dive, you can continue continue to breathe breathe from the the regula regula tor by using the following following procedure: 1. Using your hand, hold hold the mouthpiece mouthpiece loosley in your mouth. 2. Breathe Breathe the air air you need from the stream of air air escaping escaping from the mouthpiece. 3. Perfor Perform m a safe ascent. ascent. 4. It It is is a good good idea to turn off, or have your buddy
Chapter 3- Diving Skills
F IGI G U R E 3 4 1 . M O S T R E G U L A T O R S W I LLL L FR F R E E FLF L O W I F T H E Y A R E TURNED UPRIGHT UNDER WATER.
turn off your cylinder cylinder when you reach the surface soyou do not drain drain all all the air from from your cylinder. Be sure to allow allow the excess air air to escape through the sides of your mouth. Most Most will will purge through the exhaust port and prevent the pressure pressure of the air escaping to force too too much air air into into your lungs.
F IGI G U R E 3 - 4 2 . Y O U M U S T B E A B L E T O U S E T H E O R A L I N F LAL A T O R O F Y O U R B C U N D E R W A T E R O R A T T H E S U R F A C E IF Y O U R P O W E R INI N F L A T O R F A I L S .
Orally Inflating Your Buoyancy Compensator If your BC’s pow ower er inflator fails, fails, you must must orally inflate your BC during your dive to maintain maintain proper buoy ancy. To orall orally y inflate inflate your BC, use the followi following ng steps: 1. Inhal Inhale e a breath breath of air. 2. Remove Remove your regulat regulator or mouthpiece. 3. Put Put the BC’s oral infla inflator tor mouthpiece mouthpiece in your mouth. 4. Press the deflator/oral deflator/oral infla inflator tor valve valve button as you blow into the mouthpiece mouthpiece (figur (figure e 3-42). 5. Release the the deflator/ora deflator/orall infla inflator tor valve valve button. button. 6. Stop blowing into the mouthpiece. mouthpiece. 7. Remove Remove the oral oral inf infla lator tor mouthpiece and put your regulator in your mouth. 8. Clear the regulator regulator and take a breath. 9. Repeat step steps 1to 1 to 8 until until you have achieved achieved your desired state of buoyancy.
When you surface, you will usually take your regu lator lator out of your mouth and switch to to snorkel (fig (figure ure 3-
F IGI G U R E 3 -4- 4 3 . S W I TC TC H I N G F R O M R E G U L A T O R T O S N O R K E L S H O U L D B E S M O O T H A N D E A SY SY .
43). When you get ready to to descen descend, you must take your snorkel out of your mouth and replace it with with your reg reg ulator. You will practice practice regulator/snorkel regulator/snorkel exchan exchanges ges at at the surface unti untill they are simple and easy for you to per form. You must must remember remember to inhale inhale before the switch and to exhale before you inhal inhale e after after the switch to clear clear any water out of either the regulator regulator or the snorkel. snorkel.
NA UI Scuba Sc uba D i ver
V e r i l y W h a t V o u D m L e a r n e d
C O
E D
You must monitor your air consumption during your dive by frequently checking checking your submersible pres pres sure gaug gauge e (SPG (SPG). ). At a minimum, you should should check check your SPG every every 5minute 5 minutes s when you are in shallow water (less (less than 9 meters meters [30 feet feet]) ]) and more frequently when you you are in deeper deeper water (figur (figure e 3-44). You must must also begin checking your SPG SPG more frequently frequently when when your cylind cylinder er pressure drops drops below 70 bar (1000 psi). psi). When you begin diving, your air consumption will be high and you w wililll be surprised at the shortness shortness of your dives. As you you gain gain experience experience and your comfort level in the the water water increases increases,, your air will w ill last longer. When you are cold, diving diving deep, deep, or breathing ra rapid pidly ly on a dive, dive, your air consumption consumption will will increase. increase. When you are diving in in these these conditions, you must monitor your air supply more frequently. On dives to 18meters (60 feet) feet) or less, begin begin your your ascent ascent when your cylind cylinder er reaches a minimum minimum pressure of 50 bar bar (800 (800 psi) psi) or more. On deeper dives, begin your ascent when your cylinder cylinder pressure pressure reaches reaches a mini mini mum pressure of 70 bar (1000 (1000 psi) psi) or more, depending on the conditions.
F IGI G U R E 3 -4- 4 4 . Y O U M U S T C H E C K Y O U R S P G F R E Q U E N T L Y D U R INI N G Y O U R D I V E .
Review the following questio questions about regulator skills: skills: 15. You shou should ld when ever your regulator regulator is is out of your mouth. 16. Two methods to clear clear water from from your regulator regulator are the method and the method. 17. What What should you avoid when breathing breathing from a free-flowing regulator? ______________________
__________________
__________________
BUOYANCY SKILLS If there is one one skill skill that determines a person’s person’sdiving ability, ability, it it is buoyancy buoyancy control. Buoyancy control c con onsists sists of numero numerous us skills skills that you can leam leam quickly quickly by under standing and applying some basic principles. Proper buoyancy control control makes diving diving easier, adds to your enjoy enjoy ment, and helps protect the underwater environment. Many factors affect your buoyancy in the water. water. You must be aware of all a ll of them and you must know the the various means that are available available to you you for remaining in control of your buoyancy buoyancy at all all times. times. The four major major ways you affect your buoyancy are through: • The type of protective suit suit you wear. • The amount of weight you wear. • The amount of air air in in your BC or dry suit. suit. • The The amount of air in your your lungs. lungs. You must begin your dive properly properly weighted weighted if if you want to easily adjust your buoyancy buoyancy under under water. water. You fine-tune your buoyancy by the amount of air you have in your your lungs. You must must always kee keep p breathing, but you can take shallower shallower breaths to be less less buoyant or deeper breaths to be more buoyant. If you are learning learning to dive dive using a dry suit, you will will use the dry suit instead of your BC to control control your buoy ancy at depth. depth. You use the BC for surface flotation flotation and as a backup for buoyancy under water. When you pick up objects under water and carry carry them with you, you, it it wil willl probably probably be necessary for you to increase your buoyancy to offset their their weight.
Chapter 3- Diving Skills
C h e c l i l i y V o u p B u o y a n c y a l D i e S u r f a c e
ED
If you are properly weigh weighted, ted, you should be able to hover at 4 meters (15 feet) feet) with with 34 bar (500 psi) psi) or less of air in your cylinder. You must must test your buoyancy at the surface before before you begin your dive. To test test your buoyancy for scuba diving, use the followi following ng steps: 1. Make sure that your your BC is completely completely deflated. 2. Assum Assume an upright upright position position in in the water. 3. Take in a deep breath and hold iitt while while you hang hang in the water water motionle motionless. ss. If you are properly properly weighted, weighted, you will ill float float at eye eye level. 4. Exhale completely. completely. If you sink, you are properly weighted. 5. As soon as you sink, sink, kick kick back back to the surface surface and inflate your BC. This procedure gives gives you an approxima approximation tion of cor rect buoyancy adjustment. You will ill fine-tune your buoyancy adjustment adjustment as you gain gain experience in using different types of equipment (f (for or example, exposure exposure suit worn, type of cylinder cylinder used, and and size size of cylinder cylinder used) and diving in salt and fresh water. water. Your buoyancy buoyancy will will change change during your dive because because of the compression of your di diving ving suit, the amount amount of air in your BC, the items items you collect during your dive, dive, and the the use of air in in your cylinder. You will control your buoyancy during during your dive by adding to or removing removing air air from your dry suit or BC.
Descending Being Being able to descen descend easily easily in the water is is one of the important skills of diving. Diving is not much much fun if you have to struggle to get to the bottom. Some of the general steps for descending descending are: 1. Have your regulator regulator in in your your mouth. 2. Note Note the exact exact time that you leave the surface. If you are using a dive dive compu computer, ter, it will will automati cally cally start timing your dive when you leave the surface. However, a dive computer does not always record the time of day you leave the sur face. face. Having a slate or your dive dive table in your BC pocket is a good good place to record record the time. 3. Deflate your BC. If you are weighted correctly, correctly,
i
t
(L
F IGI G U R E 3 -4- 4 5 . R E M E M B E R T O E Q U A L I ZEZ E E A R L Y A N D O F T E N D U R I N G Y O U R D E S C E N T .
you will will slowly slowly sink when all the air is removed oved from your BC and you exhale. Remember to hold the power power infla inflator tor hose hose over your head and watch its mouthpiece to see the air air coming coming out as you go under water. Stop pressing the deflator/oral inflator valve button when you do not see any more air air to prevent large large amounts of water from entering entering the BC. BC. 4. Equal Equalize ize your your ears as you start your descent descent and continuously throughout your desce descent nt (fig (fig ure 3-45 3-45). ). Never Never continue descending if you feel pressure in your your ears and you cannot cannot equalize them. You will not feel feel discomfort discomfort if you are equalizing properly. 5. Exhale Exhale and begin your feet-first descent (figure (figure 346). Remember tobreathe out completel completely y and then take take in a small small breath of air. The less air you have have in your lungs during during the first first few feet ofdescent, the easier your descentwill ill be. If you descendfeetfirst, you can maint maintain ain better better contact contact with your buddy and it will will be easier easier to equalize equalize pressu pressure in your ears, mask, and sinuses. 6. Stay Stay with your your buddy buddy as you descen descend. Remain Remain close enough to touch each other and maintain maintain eye contact contact throughout the descent descent.. If one buddy buddy is having having trouble equalizing, equalizing, the other bud buddy dy must must be be patient and wait w with ith them until the the problem is corrected.
NAU I Scuba D i ver
Controlled Descents Because so many things things are happening happening at once dur ing a descent, descent, your first one will be acontrolled descent. This means means you you will will descen descend d on on a line or along the contour of the bottom. bottom. Doing a controlled controlled descen descentt will will allow you to concentrate concentrate on equalizing equalizing pres pres sure, sure, mainta maintainin ining g buddy buddy contact, and controlling controlling your buoyancy.
l i k S g n i v i D
F r e e D e s c e n ts F IGI G U R E 3 - 4 6 . D E S C E N D I N G F E E T F I R S T G IVI V E S Y O U B E T T E R ^ C O N T R O L O F Y O U R S P E E D , B U O Y A N C Y,Y , A N D A B ILI L I T Y - J
T O C LEL E A R Y O U R E A R S .
Your rate of descen descent should not be rapid. The rec ommended rate of descent is no faster faster than than 23 meters (75 feet) per minute. When you are wea wearing ring a wetsuit and make desce descents nts in open water, you will will lose buoyancy as th the e pressure pressure of the water com compresses your wetsuit. You wil willl need to add small small amounts of air air to your BC to compens compensate ate for the compression compression of the wetsuit. wetsuit. You must never sink out of control control.. You should be able to stop your descent at any time time just by inhaling inhaling a full full breath of of air. If you are wearing a dry suit, you will add air to the dry suit instead of your BC to control your your buoyancy. As your your wetsuit compresses, it it can can also loosen your weight belt if if the weight belt iis s not a compensating type. type. Your wetsuit wetsuit loses thickness as it it compresses and causes your weight belt belt to become loose around your your waist. When this happens, happens, the buckle can shift shift position, position, mak mak ing it diffi difficul cultt to locate. locate. The weight weight belt could could even even slide slide down around your legs or fall fall off. Remember Remember to check your belt as you descend descend and and then check it it again again as you reach the bottom bottom. Tighten the weight belt if if necessary. necessary. Useyour fins fins as little little as possible possible during during your descent. You should control your descent descent by your buoy ancy, not not by kickin kicking. g. As you get close to the bottom, kicking can stir up clouds clouds of silt, silt, ruin ruin the visib visibilit ility y and harm the environment. If you take in a deep breath of air air and continue to descend scend,, you are too heavy and you need to add air air to your your BC to help help slow your your descent.
Once you are comfortable with with control controlled led descents descents, descents ts.. Free your instructor instructor will will introduce you to free descen descen descents ts are vertica verticall descents descents in open water without without a line. line. When you can exe execute cute free descents in a controlled manner, you wil willl be well on your way to becom becoming ing a capable diver.
During the Dive During your dive, your goal is to maintain what divers call call neutral neutral buoyancy (figure (figure 3-4 3-47). 7). Neutral buoyancy is a state state in which you neither sink nor float float
F IGI G U R E 3 - 4 7 . M A I N T A I N INI N G N E U T R A L B U O Y A N C Y W H I L E U N D E R W A T ER E R ISI S T H E K E Y T O E N J O Y A B L E D I V ININ G .
Chapter 3- Diving Skills
when at rest. As you go deeper in the water, water, you wil willl add small amounts amounts of air air to your BC to offset wetsuit com com pression or to your dry suit to achieve neutr neutral al buoyancy. You add just a small amount amount of air air to your BC (or dry suit) suit) and then then check check to see if you are still still sinking by slowing your activity and breathing normally. If you are still still sinking, add add another another small amount of air air to your your BC (o (orr dry suit). suit). As you ascend ascend or you feel yourself risi rising ng in in the water because because of the expansion of air, you wil willl need to r y ] vent vent small amo amoun unts ts of of air from from your your BC (or dry dry suit) to maintain maintain neutral buoyancy. buoyancy. Howmuch air air you need need to vent and how often you need to vent it it depends on your situation situation and your depth. pth. To vent vent air air from your BC (or dry suit suit), ), you must get get into the necessary necessary position first. first. Dump valves are usual ly located on the upper left shoulder of your BC and on the upper upper left arm of a dry suit. Some BCs have extra dump valves on either the lower back or top right right side of the BC. If you have have an extra dump dump valve, ask your instructor instructor how to operate operate it. Slow your activity activity and your kicking kicking from time to time to to test your buoyancy. buoyancy. If you float up without kick kick ing, you are too buoyant and need need to vent some air. air. If you sink, you need need to add a little little air. air. You should strive to control your buoyancy so well well that that you can stop at any depth any time and remain remain suspended there without using your fins or hands. This technique technique is how you evaluate your buo buoyancy yancy control and will will be a part of your open-wat open-water er training training..
A s c e n d i n g For every descent you make, you must also make an ascent. Some of the general procedures for doing an ascent are: 1. Stop a minute minute and and secure any accessories you are are carrying. For example, if you you are carrying carrying a goody bag, close it and clip it to your BC. 2. Make sure your automati automatic c exhaust valve will will open if you are wearing a dry suit. 3. Find your your power-inflator hose hose and your deflator/oral deflator/oral inflat inflator or valve button button and hold the the hose up over your head. If you are wearing wearing a dry
F IGI G U R E 3 4 8 . I F Y O U A R E W E A R I N G A D R Y S U ITI T , Y O U M U S T V E N T A I R F R O M T H E S U I T A S Y O U A S C E N D .
suit, raise the exh exhaust aust valve until until it is level with or above above your shoulder (figur (figure e 3-48). Holding the hose hose over your head al also so ensures ensures that your hand will will run into an overhead overhead object object befor before e your head head will. will. 4. Give your buddy the up up signal. signal. 5. Star Startt swimming slowly slowly towards the the surface with with your buddy. Remember Remember to look up and around as you are surfacing surfacing and breathe nor mally (figure 3-49). 6. Control your b buoyancy uoyancy and your ascent by vent ing air from your BC (or dry suit). suit). Your rate of ascent must not not exceed a speed of 9 meters (30 feet) per minute if you are using dive tab tables. les. This is only 15 centimeters (6 (6 inches) inches) per second cond and is much slower slower than you natur naturall ally y want to proceed. proceed. If you are using a computer, computer, following following it will will control your rate of ascent, ascent, and it might be be slower than 9 meters meters (30 feet) per minute. 7. Slow Slow your your ascent when you get to 9meters (30 feet). feet). 8. Stop at a depth of 4 meters (15 feet) feet) for 3 min-
m
E D
NAU I Scuba S cuba D i ver
9. Proceed to the surface, infla inflate te your BC, switch from your regulator to your snorkel if if desired, and record the time you surfaced. When you you first start diving, iitt will will help if you you time your ascents and compare the ascent time with your depth depth gauge so so you you can can determine your rate of ascent. ascent. You must deve develop lop a feel for the correct rate. Your instructo instructorr will will help you do this. A slow ascent ascent rate is import important ant because the dive tables are are based on a slow ascent ascent rate. If you rise too too quickly, quickly, decompression sickness sickness can result.
V e r i f y W h a t Y o u H a v e L e a r n e d F IGI G U R E 3 4 9 . Y O U R N O R M A L A S C E N T S H O U L D A LW LW A Y S B E S L O W A N D C O N T R O L L E D .
Review the followi following ng questions about buoyancy: 18. What What are are three steps you should should take to prepare for a descent? descent?
19. What What three actions do you perform on every every descent?
20. What What three actions do you perform on on a normal ascent?
21. Four major major factors factors that affect your buoyancy are F IGI G U R E 3 5 0 . I F Y O U A R E P R O P E R L Y W E IGI G H T E D , Y O U S H O U L U B E A B L E T O H O V E R A T 4 M E T E R S ( 1 5 F E E T ] W I T H 3 4 BAR (500 PSD OR LESS OF AIR IN YOUR CYLINDER FOR A PRECAUTIONARY DECOMPRESSION STOP.
utes to do a prec precaut aution ionary ary decompression stop (figure (figure 3-50). If you can perform the stop stop while while hanging onto a line or by following the contour contour of the bottom, it makes the stop stop easier.
and and . 22. On ascent, ascent, as the air in in your BC or dry suit starts to expand, you must ________________________________
Chapter 3- Diving Skills
SAFETY SKILLS There are som some important important safety skills skills you you must master to be a responsible diver. Your goal goal is to never have to use these skill skills, s, but you must always be prepared in case you you or your buddy buddy have a problem. problem. The impor impor tant safety skills skills are: ^ • Sharing air with another another diver. diver. • Being able able to perform independent controlled controlled emergency ascents.
S h a r i n g A i r w i t h A n o t h e r Diver If your buddy forgets forgets to check their their pressure gauge at depth and runs out of a air ir,, you must know how to share share air air with your buddy. dy. If you have a conting contingency ency air bottlee, that supply, such as a pony bottl that is the best method method of sharing air air with your buddy buddy.. If you do not have a contingency air air supply, there are two two major ways to share your air air supply supply with your buddy: the alternate air air source or octopu octopus method method and the buddy breathing breathing method. These methods are called called dependent ascents because your buddy is dependent on your air supply.
m
Octopus Method _ _
J
The The pref prefer erre red d metho ethod d of sharing sharing air with anoth another er diver is is for your buddy to breathe from two separate regulator regulator which which you supply. This might might be a secondary regulator attached to to your air air supply (an (an octopus octopus regu lator or other other alternate air sourc source e regulator). regulator). This tech octopus method metho d of breathing nique is the octopus breathing (figur (figure e 3-51). 3-51). The exact exact procedure procedure you use for sharing sharing air air with with an alternate air air source depends on your equipment configu ration ration and personal preference preference.. You must must work out how how you will will share air in an emergency emergency before beforeyou start your dive. Your buddy must knowwhich which regulat regulator or to use, where where to find it, it, and how it is attached to your BC or your equipment. If they don’t, and they they run out of air during during the dive, they might grab for the first regulator they see - usually usually the one that is in your mouth! Although this regulator regulator might be the the one one you plan plan to pass, pass, you want want to pass it in a controlled controlled manner.
F IGI G U R E 3 5 2 . A S C E N D I N G INI N A N E M E R G E N C Y R E Q U I R ES E S C O O R D II N A T I N G . S IGI G N A L Y O O R B U D D Y W H E N R E A D Y
Your buddy will find that breathing from your extra regulator regulator is is just as easy easy as breathing breathing from their their own reg ulator. ulator. However, ascending will ill take some coordination coordination (figur (figure e 3-52). You and your buddy buddy must must ascend at the same same speed by maint maintain aining ing physical physical and eye eye contact. The general general steps to the octopus method of sharin sharing g air are: 1. Give your buddy buddy the appropriate regulato regulatorr for your equipment equipment configuration configuration when they signal that they are out of air.
NA UI Scuba Sc uba D i ver
3. Ask Ask your buddy buddy if they are okay and wait wait for a reply. 4. Give your buddy buddy the the up signal and wait for their their reply before before starting starting your ascent. ascent. Once your buddy buddy is breathing breathing and is okay, you should carry carry out your normal normal ascent procedure. procedure. The normal normal ascent rate is 9 meters (30 feet) per minute if if you are using using dive tables. If you are using a redundant redundant contingency scuba scuba system system, you should sti stillll perform the steps steps of ascending together after after you pass the system system to your your buddy.
Buddy Breathing Method
F IGI G U R E 3 5 3 . M A I N T A INI N P H Y S I C A L C O N T A C T T H R O U G H O U T Y O U R ENTIRE OCTOPUS ASCENT.
2. Hold on to them with one hand and position your buddy in front of you. This position position allows your your buddy to keep keep the mouthpiece of the sec ondary regulator easily in their mouth mouth and allows you both to to maintai maintain n physical physical and eye contact (figu (figure re 3-53).
The other method method of sharing air air with with your buddy is the buddy breathing method. If you do not have a sec ondary regulator regulator or redundant redundant contingency contingency scuba scuba sys sys tem, you share air air by passing passing your primary primary regulator regulator back and forth. This procedure is simple, but requ requires ires a higher level of ski skillll from you and your buddy buddy. Buddy breathing breathing and ascending at the same time can be done done successfully successfully with trainin training g and practice in confinedwater. water. However, you must freque frequently ntly review the steps if buddy breathing breathing is to be successful successful when it it might be neede needed. If your scuba is not set set up with a secondary secondary regula tor, you should rehearse buddy-breathing buddy-breathing techniques before entering entering the water. You should practice practice again again in shallow shallow water at the beginning of every dive to renew your skill skills s and coordinate procedures. Use the followin following g steps for buddy breathing: 1. Take a deep breath of air air and start exhalin exhaling g when your buddy gives givesyou the out of air air signal. 2. Grasp your buddy’s right shoulder strap with your your left hand. 3. Hold your regulator regulator by the hose hose and near the mouthpiece and remove it from your your mouth, using your right hand. Turn the mouthpiece mouthpiece down so the regula regulator tor does not freeflow. freeflow. Keep exhaling exhaling a small small stream of bubb bubbles. 4. Pass the regulator regulator to your your buddy bythe hose and let them guide th the e regulator into their their mouth. Always give them access to the purge button so they can clear clear the second stage of water. 5. Continue Continue to use your left hand hand to hold your
Chapter 3- Diving Skills
El
E l
buddy by the right shoulder shoulder of their their BC. 6. Allow your buddy buddy to take two two breaths of air air from the regulator and then pass the the regulator regulator back to you. Never let go of the hose. You must main main tain contact and control control of your air supply at all all times. 7. Take two breaths of air from the regulator regulator and then pass the regulato regulatorr back to your buddy. 8. Give your buddy buddy the the up signal and wait for their their up signal back and begin your ascent when the situation is stabilized. stabilized. 9. Repeat the exchange process while while doing doing a slow, controlled controlled ascent ascent to the surface. Once Once you start buddy breathing breathing and ascending, ascending, do not try to change rhythm or techniques during during the ascent. ascent. During buddy buddy breathing, you must must remember remember to exhale small small bubbles bubbles whenever whenever the regulator regulator is out of your mouth. You and your buddy must control your buoyancy and and you must maintain maintain physic physical al contact. Unless you practice buddy breathing breathing on a regular regular basis, it is unrea unrealist listic ic to expect that you could pe perform rform it in an emerge emergency. ncy. Divers who are not skilled skilled in in buddy buddy breathing breathing but attempt to do it anyway during an emer gency gency risk serious injur injury. y.
Independent Emergency Ascents If you run out of air and you cannot obtain air air from your your buddy, you must make an independent independent ascent to the surface. surface. There are are two types of emergency ascents: swimming swimming and buoyant. buoyant. The one you do depends prim primar arily ily on your your status at the time you realize you are out of air.
Swimming emergency swimm ing ascent when You do an emergency when you run out of air air at at shallower shallower depths (about (about 18 meters or 60 feet). feet). They can be done from greater depths but con tingency air air supply is superior and recommended ended for deepe deeper water diving. You simply look up to mainta maintain in an open airway airway and swim to the surface while exhaling exhaling a continuous stream of bubbles from your regulator regulator (figure (figure 3-54). You always keep the regulator regulator in your your mouth dur ing an emergency swimming ascent, because as the water pressure decreases, you will will get another another small breath breath of air air from your cylinder cylinder.. You must also remember tobe ready to vent air from your BC to control your your buoyancy during during the ascent. During your NAUI Scuba Diver certificatio certification n course, course, you will will practice emergency emergency swimming swimming ascents ascents (ESAs) (ESAs) during during your confined-water confined-water traini training ng sessio sessions. ns. During thes these e sessions, ns, your instructor instructor will will tell you to inhale and then start your ascent. You must remember ember that in a real emerge emergency ncy,, you will will exhale and then try to take a breath but little or no air w will ill be available. available. You will ill also discover that the expanding air flows out from your lungs almost almost natural naturally ly with very little little effort on your part.
Buoyant
F IGI G U R E 3 5 4 . K E E P T H E R EG E G U L A T O R INI N Y O U R M O U T H W H E N D O I N G A N E M E R G E N C Y A S C E N T .
buoy ant emergency emergency ascent whe You do a buoyant when you run out of air air at greater depths. You drop your weight belt and gently exhale all all the way tothe surface. surface. If you are wearing wearing a wetsuit and drop your weight belt, you must get get yourself yourself horizontal horizontal in the water and be facing facing up to create as much surface area as possible possible to slowyour ascent as as you approach the surface. surface. You
NAU I Scuba S cuba D i ver
must also remember to vent air air from your BC to slow your ascent. ascent. Your ascent ascent rate will ill increase increase due to the buoyancy of your wetsuit and its expansion. If you are in warm water and d drop rop your weight b belt, elt, you will will have to swim swim to the surface. surface. However, ever, not hav ing the extra weight will will help make your ascent easier.
V e r i l y W h a t Y u n H a v e l e a n e d Review the following following questions about safety safety skills: skills: 23. Each Each diver diver should should take take breaths when sharing air air with one regulator. regulator. 24. How do you know which which of your your buddy’s two regulators to use during during an assisted assisted ascent? ascent? ____________
G e n e r a l G u i d e l ini n e s If you find yourself without air, air, you might wonder wonder which which method of ascent you should should use. The method method you should use d dep epen ends on the situation, situation, but the follow follow ing general guidelines guidelines should help you decide decide which method to use: • Discuss and agree on emergency procedures with with your buddybefore your dive. This discussion should should include include the signals you will ill use in an an emergency and your respective equipment equipment configurations. configurations. • The optimal method of knowing that you have ILL] air air in in an emerge emergency ncy is to to carry a contingency contingency air air supply like a pon pony y bottle. This is the easiest easiest and safest safest method method for reaching reaching the surface if you find that your prima primary ry scuba unit is not provid provid ing air. Simply place the the backu backup p regulator in your mouth, mouth, clear clear it, and continue breathing as as you ascend. • Adependent ascent, breath breathing ing from from your buddy’s buddy’s air air supply, is better than an independent independent swim ming or buoyant ascent becaus because e you have a sup ply of air during th the e ascent ascent.. Breathing Breathing from your buddy’s back-up regulat regulator or is better than trying to perform buddy breathing. Remember ember that buddy breathing breathing takes practice and you and your buddy must both be comfortable comfortable with with buddy breathing. • You should consider consider doing an independent independent ascent only if your buddy buddy is not available. available. It should should be obvious obvious that not running out of air in the first first place is the bes best course of action. action. Monitor Monitor your submersible submersible pressure pressure gauge gauge frequently frequently during during your your dive to avoid avoid running out of air. Making this one one of your diving habits will ensure that all of your ascents will be normal ascents ascents and you wil willl not need to worry about decisions regar regarding ding emergency ascents.
25. If you are plann planning ing to use buddy breathing breathing in an emergency, you should
26. When is it appropriate to choose choose a buoyant emergency ascent?
BUDDY SYSTEM It is easy to kee keep p track of your buddy in controlled controlled conditions conditions where the visibi visibilit lity y is good and the the area is limited. Maintai Maintaining ning contact with your budd buddy y in open open water is not as easy. easy. Diving Diving is fun, but it is not as fun if if you spend most most of your time looking looking for your your buddy. buddy. If you use the the following following points to ke keep ep track of your buddy buddy,, diving diving will w ill bevery enjoyable: enjoyable: • Agree ree on a leader for each dive. IL L • Discuss the dive before you get in the water and agree agree on the location, location, purpos purpose, e, activity, activity, and general general course course you will will follow under water. water. • Mainta Maintain in your same position relativ relative e to one another for your entire dive dive.. If you start out on on the right right side of your buddy, stay on the right right side for the entire entire dive. dive. It is more more enjoyable to dive side by side than for for one of you to be in front and the other buddy buddy following following behind. • Establish your direction of travel under under water and then then follow that heading until until you or your buddy suggest gest a change or stop stop with a clear clear signa signal.l. Make sure your your buddy acknowledges the signal signal before you change direction. direction. If you you do get separated separated from your buddy, you wil willl
Chapter 3- Diving Skills
G 2
have a general idea idea of where to locate your buddy. • Use the lost buddy procedure if if you do lose your buddy. The common procedure is: 1. Get yourself vertica verticall in the water and look in all directions for for your buddy buddy or their their bubbles (figure 3-55 3-55). If you are are in low visibi visibility lity water (3 meters or 10 feet or less) less),, retur return n to where you last last saw your buddy and start start your search there. 2. Rise Rise about 3 meters (10 feet) feet) in the water water and look again for your buddy or their their bub bles if you did not find them the first time. 3. Ascend slowly slowly to the surface surface after after a minute minute if you do not seeyour your buddy. Keep turnin turning g as you ascend and look look for your your buddy or their bubbles. 4. Surface, Surface, note your position relative relative to two points on the sho shore, re, and wait for for your buddy. When your buddy surfaces, get back together and continue your dive. 5. Use one of the followi following ng options, depending on your circumstances: • If you are diving where where help help is readily availabl available e to assist assist you in a search for a lost buddy, signal for help if if yo your ur buddy does not
surface surface within within 5minu 5 minutes. tes. It is your role in the emergency to contact and guide the help. • If you are diving in a remo remote te location, you might be your buddy’s only source of help if your buddy is in ttrouble rouble under water and minutes minutes are critic critical. al. You will have to search search for your lost buddy buddy within within your capability capability to do so, and be prepared to render aid as need ed. Before you put yourself in th this is type of situation situation,, prepare by taking the NAU NAUII Advanced Advanced Scuba Diver Diver course and the NAUI Scuba Rescue Diver course. As you and your your buddy gain exper experience ience together and get get to know know one another, it it wil willl become easier to stay toge together. You will becom become famili familiar ar with with each other’s other’s diving diving styles and you will ill be able to to function function as a true team team with minim minimal al effort. Developing Developing this harmo ny should be your goal, because diving diving with a good buddy is diving diving at its best. best. Your buddy also makesworking working with equipment easier. For example, if if your cylinder cylinder slips out of its tank strap under under water, it is easier for your buddy to to refasten the cylinder than for you to take offyour BC and fix the cylinder cylinder yourself (fig (fig ure 3-56). A goodbuddyis more likel likely y to notice developing problems, such as a loos loose tank strap, before you do.
I n g S k i l l s
F IGI G U R E 3 5 5 . B E U P R I G H T INI N T H E W A T ER E R A N U L O O K I N A L L D I R EC EC T I U N S E U R Y O U R L O S T B U O D Y .
81
NAUI Scuba Diver
COMMUNICATION There are are standard signa signals ls you need to know to communicate unde underr water as well as on the the surface. The NAUI NAUI Diving Diving Hand Signals Signals are standard in the United States States diving diving community and are usuall usually y recog recog nized in other countries as well well (fig (figure ure 3-57). As a certi fied diver, you must be able to correctly correctly identify identify and use each signal. signal. Once you start using them, they are easy to remember. Remember, Remember, for a signal signal to be effective, effective, all all con cerned must discuss discuss it and agree upon it before you start the dive. dive. Proper use of signals signals is necessary for every dive. Be sure to discuss the signal signals s you are accustomed to using with with any new buddy.
F I G U R E 3 5 6 . I T 18 M U C H E A S I E R T O S O L V E P R O B L E M S U N D E R W A T ER E R I E Y O U W O R K W I TH TH Y O U R B U D D Y .
V e r i f y W h a t Y o u H a v e L e a r n e d Review Review the followi following ng questions about the buddy system: 27. Three recommended techniques that help maintain maintain budd buddy y contact while diving are and 28. The steps to the recommended lost buddy plan plan are: _______________________________
H I
Underwater Communication You probably realize realize by now that communicat communication ion is not easy easy under water. When you give a hand signal, signal, you must must display it distinctly distinctly and you must must wait for a response from your buddy. Your buddy acknowledges the signal by either repeating the signal or giving giving you the okay signal signal (figure (figure 3-58). Along with the standard standard hand signals, signals, divers create their own hand signals. Some divers even learn learn American Sign Language to expand expand their vocabulary vocabulary for underwater underwater communica tion. Always remember to review your hand signals signals with your buddy before each dive. You can write write messages to your your buddy on an under water slate slate (figu (figure re 3-59)- This This is a handy way to give detailed detailed messages. You can also use the sen sense of touch to communicate. You can touch your buddy to gain their attention or or to let another diver know you are nearby. nearby. Try to avoid touching touching another another diver when when you are behind them, especially iiff they are not not aware of your presence. It is easy to frighten frighten someone in this situation. situation. You can use and and hear audible audible signals signals under water although although you cannot cannot determine sound sound sources by direc tion under water. You or a boat can produce produce sound sound sig nals. Diver-produced audible audible signals signals include include rapping on your cylinder cylinder with a knife or other hard object, object, or using special full-face full-face masks or devices that allow allow you to speak to your buddy under the water.
HI
Chapter 3- Diving Skills
i n g S k i l l s
Down
I'm out of air
Share air
Dang er
Low on air
Help! (surface)
Ok (surface)
Ok (surface)
Pick me up (surface)
F IGI G U R E 3 5 7 . E V E R Y D IVI V E R S H O U L D U S E T H E S E S T A N D A R D S I G N A L S .
»
J
NAU I Scuba Sc uba D i ver
l i k S g n i v i D
F IGI G U R E 3 -5- 5 8 . T H E O K A Y S I G N A L I S B O T H A Q U E S T I O N A N D A N A N S W E R . Y O U W I L L U S E T H I S S I G N A L R E P E A T E D L Y
Most Most charter charter boats have an underwater reca recallll device that soun sounds ds like a siren. siren. If you hear the recall recall signal while while you are under water, you must surface and look to the boat for instructions. instructions. They might need to reposition the anchor and just want to see seewhere all all their their divers are, or they might might need to have everyone return to the boat because of an emergency.
S u r f a c e C o m m u n ici c a tit i o n At the the surface, you can can use use different different types of audible audible and visual visual signals signals to communicate. communicate. You use use some of the standard hand signals at the surface. For example, l y \ l if you wave wave to som someone eone from the the surfa surface, ce, it is a sign of distress, NOT a way to say say hello. hello.
F IGI G U R E 3 -5- 5 9 . U N D E R W A T E R S LA LA T E S A R E A N E A S Y W A Y T O S H O W Y O U R B U D D Y A D E T A I L E D M E S S A G E .
Dive boats have a blue and white flag that they fly when they want divers to return to the boat (figu (figure re 360). When you surface surface and see this flag, return return imme diately to the boat. Audible communicat communication ion is possible at the surface, but yelling yelling is not effective at a long distance distance over the water. A whistle whistle produces produces a loud sound sound that you can hear at a considerable distance. Also, Also, using a whistle whistle does not take a lot of energy. energy. A repeated series of four short blasts on a whistle whistle is a standard distress signal.
V e r i l y W h a t y o n H a v e L e a r n e d Review the following following questions about communication: 29. The four ways ways of communicating communicating under water water are . , and 30. The two ways ways of communicat communicating ing at the surface are are and and . 31. When you are given a hand hand signal signal under water, you must . 32. What What is is the most most important important point point to remember regarding diving communication? ______________
_____________
_________________
________________
_______________________
F I G U R E 3 -6-6 0 . I F Y U U S E E T H E R E C A L L F L A G F L Y I N G U N Y O U R C H A R T E R B O A T , Y O U M U S T R E T U R N I M M E D I A T E LYL Y T O T H E B O ATA T .
1
8 4
H A N D L IN IN G Y O U R S C U B A E Q U I P M E N T I N T H E W A T ER ER Usually Usually you don your scuba equipment out of the water, go diving, diving, and then remove your your equipment after you getout of thewater. There will will betimes when you needto don or remove your your equipment in the water. For example, the boat you are using might might be too small to permit much equipment handlin handling g while you are on board. You might also need to adjust an item of gear in in the water and and will need to rem remove it to adjust it. If your scuba unit is caught in fi fishing shing line or kelp, kelp, you can remove the unit soyou can see the problem and correct correct it.
R E M O V IN I N G A N D R E P LA LA C I N G Y O U R S C U B A U N I T O N T H E S U R F A C E A N D U N D E R W A TE TE R Removing your scuba unit in the water is as easy as as removing a jacket (f (figur igure e 3-61). Use the followin following g steps to get out of your scuba unit: unit: 1. Uncli Unclip p any any buckles you have on the front of the BC. 2. Undo the waistband. waistband. 3. Pu Pull your left arm out of the left armhole of the BC and use your right right arm to pull pull the scuba unit around to your right. There are many ways ways to don your scuba unit (fig (fig ure 3-62). Your instructor instructor will will showyou the way they want you to don don your your unit. unit. One method you might might be shown is to don the un unit it over over your head. head. To donyour scuba unit unit by passing passing it over your head, use the followi following ng steps: 1. Position your BC in front of you you with the cylinder under under the BC. The first stage stage of the the regulator regulator is toward you and the second second stage is in your mouth. 2. Keep the hose for for your your second stage between your arms. If you do not have the hose hose between your arms, the hose will ill be trapped under under your shoul shoul der strap when you lower the cylinder cylinder in in place. place. 3. Slip Slip your arms into the armholes armholes of the BC BC until until the unit unit is above above your elbows. ows. It wil willl seem seem like
< <
'
F IGI G U R E 3 8 1 . R E M O V I N G Y O U R S C U R A U N I T I N T H E W A T E R ISIS A S EASY AS REMOVING A JACKET.
you are putting putting the unit unit on upside down. 4. Grasp either side of the the tank with with each hand. 5. Slide Slide the unit over your head and down down your back as you arch yo your ur back. 6. Feel around your waist waist for the two two ends of your waistband or strap. 7. Fasten your your waistband or strap snugly snugly and re-clip any buckles at the front of your BC. 8. Straighten Straighten out your second s stag tage e regulator regulator hose and reposition the mouthpiece mouthpiece comfortably in your mouth. If you are on the surface, you want your scuba scuba unit to be buoyant so it wil willl float. float. If you are on the bottom bottom,, you want the scuba unit unit to be negative while donning it.
NAU I Scuba S cuba D i ver
F IGI G U R E 3 -6- 6 2 . R E M E M B E R T O W O R K A T A S L O W A N D S T E A D Y P A C E W H E N D O N N I N G Y O U R S C U B A U N I T I N T H E W A T E R .
Always breathe from your regulato regulatorr when you are donning the scuba scuba unit. When you are at the surface, you will will slip under water as you pass pass the the cylinder cylinder over your head and the regulator will will give you a source source of air. You must learn to refasten your waistband and buckles by feel. Before you refasten your waistband and clips, feel to be sure that your your straps are not twisted and your hoses are not trapped. Work at a slow and steady steady pace pace when removing removing and replacing replacing your scuba scuba unit. unit. You should be able you han dle your equipment independently, independently, but there is nothing nothing wrong with asking asking your buddy for assistance if you have difficul difficulty. ty. An extra set of hands and eyes is useful and saves time.
R E M O V I N G A N D R E P L A C IN I N G Y O U R W E IGIG H T G E LT L T O N T H E S U R FA F A C E A N D U N D E R W A T ER ER Handling a weight belt in the water can be awk awk ward, but with practice, practice, working with a weight belt is not as difficu difficult lt as it seems. There are a few important points to remember remember when working with weight belts: belts: • Always Always handle a belt by the free end to prevent the weights from slipping off off the belt. • Gravity will will pull pull the belt towards towards the the bottom bottom
unless you support the belt with with your your body. • Keep Keep your body body in a horizontal horizontal position at |T ^ | all times when removing and replacing the weight belt. • Work at a slow and steady pace when removing and replacing the weight belt. belt. To remove remove the weight belt to discard it or to hand it out of the water, use the following following steps: 1. Undo the buckle and pull pull the tai taill of the weight belt free of the buckle. 2. Hold the free end of the weight weight belt in one hand and pull pull the belt completely completely away from from your iL L j body body.. The weights will hang in a direct line towards towards the bottom (figur (figure e 3-63). 3-63). 3. Release the weight belt. If you are handing the weight belt belt out of the water, be sure that the per son you are handing handing it it to has a firm grip on the weight belt belt before you let let go. go. You use the same procedure to remove and replace your weight weight belt belt on the bottom as you you do on the surface. Your instructor instructor will will showyou the procedur procedure e they want you to use. If you use use a right-hand release release to your weight belt, one method method to remove and replace you yourr weight belt belt in in the water is is as follows: follows: 1. Assum Assume a facedown position in the water. 2. Undo the buckle and pull the tail tail of the weight weight belt free of the the buckle.
Chapter 3- Diving Skills
V e r i t y W h a t t t o n H a v e L e a r n e d Review the following question questions s about handling handling your scuba equipment in the water: 33- The prima primary ry differenc difference e between donning donning your cylinder cylinder at the surface and donning your cylinder under water is
34. You can keep your regulator regulator hose hose from becoming trappedwhen you don your your cylinder over your your head by by
35. Handling Handling your weight belt belt is easier if you remember to and and _____________________
____________________________
F IGI G U R E 3 6 3.3 . A I M S P U L L T H E W E IGIG H T B ELE L T C O M P L ETE T E LYL Y C L EA EA R O F Y O U R B O D Y B E F O R E D R O P P I N G IT .
3. Hold the free end of the the weight belt in your right hand and pull the weight weight belt around your right right side to your front as you are rotating rotating in in the water to your left. Remember Remember that you want to keep your body between the weight belt belt and the bottom. 4. Make your modification modifications s to your weight belt. 5. Hold the weight belt with the buckle in your left left hand, the free end end in your righ rightt hand, and be sure that there are no twists in the belt. 6. Transfer Transfer the buckle to your righ rightt hand and move the entire entire weight belt belt down so that your your right thigh thigh supports it. 7. Drop the buckle and rotate your body to the left. The weight belt wi willll drape across across your thighs. 8. Reach down your left side with with your left left hand and feel for the buckle. 9. Slide Slide the weight belt up your back and position it underyour cylinder cylinder and BC at your waist. 10. Re-buckle the weight weight belt securely. securely. If you use a left-hand release to your weight weight belt, you can use the previous procedure with with the opposite hand and rotating in the opposite direction.
N A V I G A T I O N S K I L LS LS When you are out of the water, you are constantly constantly using navigation navigation skills. Maps, Maps, street street signs signs,, and land marks help you locate a destination and return return you to your starting starting point. There are no street signs under water, but you you can use a combination of natural natural and compass pass navigat navigation ion to keep track of your loca location tion and travel during a dive. dive. This section section will will introduce introduce you you to some of the fundamentals fundamentals of underwater navigation. navigation. You can learn mo more re about this necess necessary ary skill skill in a NAUI Underwater Underwater Navigation Specialty Specialty course. course.
Natural Navigation You can avoid avoid long surface swims by by ending your dives at predetermined locations. To know where you you are and be able to get where you want want to go and back, is the objective objective of of underwater underwater navigation. navigation. By recognizing and using natural natural aids to navigation, navigation, you can achieve this objective. Natura Naturall aids under water w wililll soon become as use ful ful to you as street signs. Ripple Ripple marks in the sand on the bottom bottom form paralle parallell to the shore. As you get
NAU I Scuba S cuba D i ver
C O
closer to shore, the ripple ripple marks get closer together. together. This fact gives you you one one useful reference. The positions of the sun and shadows dows at the start of your dive are another another useful reference. The back-and-forth movement of water close close to shore is known as surge. usually surge. The movement is usually toward and away from shore, so this this gives you anothe anotherr clue to your location. The water water gets deeper as you go furth further er away away from shore and shallower as you return return to shore or approach reefs. You will ill see underwater landmarks, such as rock formations, large and unique plants, crevices, crevices, and wrecks wrecks (figur (figure e 3-64). You and your buddy can keep track of your position position under water and be able able to return return to your startin starting g point without surfacing by paying attention to all all of these nat ural aids.
F IGI G U R E 3 - 6 4 . R E E F F O R M A T I O N S A R E E X C E L L E N T N A T U R A L A IDID S FOR NAVIGATION.
C o m p a s s N a v igi g a t ioi o n When you you dive at night or in water with limited vis vis ibility ibility,, natura naturall aids are not as helpful to you. you. You must rely rely more on a compass and your your depth gauge. Using a reckoning, compass allows allows you to navigate navigate by dead reckoning, which which can be very accurate. accurate. The compass shows you directions and your depth gauge tells you your ver vertic tical al position in the water. water. A diving comp compass must be filled filled with liquid liquid to with with stand pressure underwater, have have a reference line line called called a lubber line, and have a means, such as a rotating bezel, bezel, to showthat that you are on a selected bearing bearing or directio direction n (figur (figure e 3-65). Because a compass is magnetic, ferrous ferrous (iron or steel) objects objects close close to it wil willl affect it. metal (iron When you use a compass, you keep keep the lubber lin line e aligned with the centerline centerline of your body. dy. You can wear r ^ | your com compass on on your your wrist or or mount mount it on your con conso sole le LS^J with the rest rest of your diving instruments (figure (figure 3-66) 3-66).. Where Where you carry the c com ompass pass is not critical; critical; having it aligned aligned with your body is. When you reference your compass, pass, always be sure sure that that you are lined lined up with with the lubber line line and that the the compass pass is level. The compass needle always always points to magnet magnetic ic north. If you point the lubber line line towards shore, the the compass needle points to one point. point. Rotate Rotate the index
■
#4EV
On
F IGI G U R E 3 - 6 5 . T H E U N D E R W A T E R C O M P A S S M A K E S N A V I G A TIT I O N A C C U R A T E D U R I N G A D I V E .
F IGI G U R E 3 6 6 . Y O U M U S T A L W A Y S A L IGI G N T H E C O M P A S S W I TH TH T H E C E N T E R O F Y O U R 6 0 D Y.Y .
Chapter 3- Diving Skills
F IGI G U R E 3 -6- 6 7 . Y O U M U S T A I M S A L IGI G N T H E L UB U B B E R LIL I N E W ITI T H YO YO U R
Simple navigational techniques make diving more enjoyable. Knowing where you are underwater underwater will help you avoid long surface swims and help you to relocate interestin interesting g areas. areas. You will ill save time, air, air, and be able to spend more time enjoyi enjoying ng the objective objective of your dive. You must be be able to perform the basics basics of navig naviga a tion that you will learn in your NAUI NAUI Scuba Diver certifi cation course. course. To learn more about underwater underwater naviga tion, enroll enroll in a NAUI continuing continuing education course, urse, such as the NAUI Advanc Advanced ed Scuba Diver cert certific ificati ation on course, or a special specialty ty course such as Search and Recovery Diving.
OO 00
B O D Y A N D W I T H T H E D I R EC E C T I O N YO YO U W A N T T O S W I M .
V e r i f y W M Y o n H a v e L e a r n e d marks on the bezel bezel to mark the position of the needle, and you will ill know that whenever the compass pass needle is pointing pointing in in between the marks, you are swimming towards shore. If the compass needle points opposite the marks, you know you are headin heading g away from shore. When you decide decide to begin your dive in a certain certain direction, direction, you sight sight over the level level compass compass and set the index marks marks on the rotating rotating bezel bezel so that they line line up with with the compass needle. needle. Then, by keeping yourself yourself aligned with with the lubber line line,, and the compass pass needle aligned with the index ma marks, rks, you can mainta maintain in your course very accurately accurately (figur (figure e 3-67). Usually, Usually, you only need to reference the compass occasio occasional nally ly to make sure you are on course. course. If you need need to to navigate precise precisely, ly, you must reference the compass frequently. frequently. A reciprocal course is made when your outbound course is a straight lin line e and halfway through your dive, you make make a 180° turn, which which the compass enables you you to do precisely. To make a 180° turn, turn, you swivel ar around ound until until your your compass pass needle needle is directly directly opposite opposite your origi origi nal reference reference marker. Even if if you do do not follow a specific pattern during your dive, the compass pass can still still be helpful. helpful. You and your buddy can surface near the end ofyour dive, line line up the the lubber line with with your body body and the direction direction of your exit point, set your bearing with the index marks on the bezel, subme submerge, rge, and follow follow that that heading heading to your destination. destination. Swimming under water is usually usually easier than swimming on the surface.
Review the following following questions questions about navigation: 36. Three natural natural aids to navigation navigation are and 37. When you are usi using ng a compass compass for naviga navigation, tion, you should and and . 38. A reciprocal reciprocal course is a _________________________
______________________________
D I S A S S E M B L IN IN G Y O U R S C U B A G E A R After diving, diving, you must disassemb disassemble le your scuba gear and rinse it with with fresh water. To disassemble ssemble your scuba unit, unit, use use the following following steps steps: 1. Turn off your air. The cylinder valve turns off in a clockwise direction. 2. Push Push and hold the purge button on one of your secondstages or powerinflat inflator or to relieve all the air air pressure in the hoses of your regulator regulator (figure (figure 3-68). 3. Unscrew the yoke screw screw from the cylinde cylinderr valve (figure (figure 3-69) or unscrew the DIN regulator from the DIN valve. 4. Dry Dry the dust cap attached to the first first stage of your regulator (figure (figure 3-70). 3-70). 5. Replace Replace the the dust cap over the inlet inlet to to the first stage of your regulator regulator and tighten the yoke yoke screw screw until
m
i s
89
j
F IGI G U R E 3 6 8 . P U R G E T H E A I R F R O M Y O U R R E G U L A T O R A F T E R Y O U
F IGI G U R E 3 6 9 . T H E Y O K E S C R E W O N S C R E W S E A S ILI L Y O N C E Y O U
HAVE TURNED OFF YOUR CYLINDER.
HAVE PURGED YOUR REGULATOR.
F IGI G U R E 3 - 7 1 . R E P L A C E Y O U R D U S T C A P O V E R T H E F I R S T S T A G E A N D T I G H T E N T H E Y O K E S C R E W F I N G E R T I G H T .
it is finger tight (figure 3-71). If you have have a DIN regulator, regulator, screw in the dust cap. cap. 6. Remove your BC from the cylinder. cylinder. 7. Turn Turn the BC upside down down so that the the power-infla tor hose attachment attachment point is the lowest point. This will will allow any water in the BC to drain down down into the power-inflator hose. hose.
8. Press Press the deflator/oral inflator inflator valve button button to allow allow the water to drain drain out of the power-infla tor hose. 9. Rinse Rinse your equipment with fresh water and allow it to dry completel completely y before storing it.
CONCLUSION Breathing under water is not not difficult. difficult. The hardes hardestt part of scuba scuba diving physical physically ly is putting the gear gear on, and even that that becomes easy with with experience. experience. You need to deve develop certain certain breathing breathing habits for for some circum circum stances, but other than that, there isn’t isn’t much to learn about about breathing breathing on scuba. You will will soon find yourself feeling confident about about handling handling your equipmen equipmentt in the water. The more prac prac tice and experien experience ce you have, the easier it wil w illl become. Your goal is is to make make working with with your equipment equipment as easy as your instructor instructor makes it look. If you find yourself struggling with your gear, this indicates that that you do not understand something about howyour gear works. Learn to work slowly and deliber ately. ately. Think of the ste steps involved in performing a skill skill with an item of gear and then execute execute them one one at a time. Practice Practice wil willl help make the the steps teps blend together together into a natural natural motion for you. you. Learning Learning the other skills skills of diving, diving, such as buoyan buoyan cy control, entries, entries, and emergency procedures requires training g and practice. You will ill start to develo develop p more trainin these skills during your NAUI Scuba Diver certifi certificatio cation n course and and will will polish them them with additional additional NAUI con tinuing tinuing education cours courses es (figur (figure e 3-72).
F IGI G U R E 3 7 2 . D IVI V INI N G I N O P E N W A T E R R E Q U IRI R E S Y O U T O U S E A L L O F T H E S K I L LSL S Y O U W I LLL L L E A R N D U R I N G Y O U R N A U I SCUBA DIVER CERTIFICATION COURSE.
CHAPTER
NAU I Scuba S cuba D i ver
L EA R N IN G G O A L S In this chapter you will: • Learn Learn about som some of the characteris characteristics tics of air air and water. • Be introduced to the concept concept of buoyancy and how if affects you under water. water. • Understand the concept of pressure and how it affects the volume and density of air air in a closed container. • Learn how the pressure of the water affects the air air spaces in your your body and how to prevent problems occurring occurring from the pressure change changes. s. • Be introduced to different different types of lung overex pansion injurie injuries s and how to prevent them. them. • Learn about the indirect indirect effects of pressure pressure on your your body by means of the gasesyou breathe breathe while diving. • Understand Understand the thermal effects effects of the air air and water temperature and your your body. The underwater world presents presents a new and tota totally lly different environment from the the air air world in which which you live. live. As you descend below the surface, surface, the increased increased pressure pressure will ill have direct direct and indirect indirect effects on your body. dy. However, ever, most of your time underwater, you will will not be aware of o orr feel these effects. This chapter chapter addres addresses physica physicall properties of air air and water and ways specific parts of your body are affected affected while while diving. diving. The better you understand these differ differ ences, the easier it wil willl be for you to function as a diver.
heavier heavier than than the first. first. This This is because the compressed air air is more dense. Density is the mass of an element per unit unit of volume. The density of a gas depends on its pres sure and tempe temperature. The density density of a liquid, like water, is constant constant over a wide rrange ange of temperature and pressure. Asyou can can see from the the above example, air has weight. One One liter liter of air weighs 1.25 grams. grams. In the Imperial Measurement System this is usually expressed as 0.08 pounds pounds per one cubic foot of air. One liter liter of fresh water weighs weighs 1.0 kilogram kilogram and one liter liter of salt water, because because of it dissolv dissolved ed salts and minerals, weighs weighs IT ^ l 1.02 1.025 kilograms. kilograms. Again in the Impe Imperia riall System these are commonly expre expresse ssed d as pounds pounds per cubic foot, that is, 62.4 pounds per cubic cubic foot for fresh fresh water and 64 pounds pounds per cubic foot for salt salt water.
Outlie Air You Breathe Most of the the time, we do not think think about air, air, because breathing is an automatic activity activity and we cannot see or feel the air air around us.
Composition Air is is a mixture of differ different ent gases. The gase gases in air air are colorless, odorless, odorless, and tasteless. Air is composed ITT IT T"! of approximately approximately 20.9% oxygen oxygen, 78% nitrogen, nitrogen, and 1.1% miscellaneous miscellaneous gase gases, s, such as argon and carbon carbon dioxide (figure 4-1).
Oxygen (20.9%)
DIRECT EFFECTS OF PRESSURE When you descend in water, the force from the com binedweight of air and water will ill increase. This force is pressure ure.. In this chapte called press chapter, r, you will learn how pres pres sure increases under water and how it affects your body. body.
Density anil Its Effects If you pick up up one one scuba scuba cylinder with air air in in it at at 1 ILL] bar (1 atmosphere atmosphere)) and another just like it fille filled d with air to its rated rated pressure, the second is about 2-4 kg (4-8 lb.) lb.)
Nitrogen (78%
F IGI G U R E 4 1 . A IRI R ISI S A M I X T U R E O F G A S E S .
Chapter 4- Diving Science
□
The most important component of air to us is oxyge oxygen. We cannot survive survive without oxygen. You can breathe pure pure oxygen for limited limited periods, periods, but pure oxy gen can be extremely hazardous above and underwater. underwater. Nitrogen is a metabolically inert g gas. It does not react in our bodies when we breathe it under normal conditions. conditions. However, dissolved nitrogen nitrogen is present present in your body, and additional additional nitrogen is absorb absorbed ed in your body when you are under increased pressure underwater. Some divers use special mixtures mixtures of gases, such as nitrox, for diving. These mixtures contain contain different per centage centages of oxygen oxygen and nitrogen than air. air. Diving Diving with special gas mixtures requires additional training and specialized equipment. equipment. The NAUI NAUI Enriched Enriched Air Nitrox (EAN) (EAN) Diver Specialty Specialty course provides provides the additional additional training training you will will need need to to dive with nitrox.
colors, our hearing, our ability ability to retain heat, and our abili ability ty to move move through it, compared to to air.
Characteristics
V i s i o n
Air can can be easily easily compressed. When pressure is applied to a volume of air, air, it can beforced to occupy occupy a much much smaller smaller area. With a compressor, pressor, we can squeeze a large amount of air air into a smaller smaller space, making it denser denser than normal normal and therefore therefore heavier than normal. For example, the com compressed air air in a scuba cylinder, cylinder, when released, released, would fill fill a space equiva lent to a small closet closet at atmospheric atmospheric pressure. This is why a full full scuba cylinder weighs more more than an empty scuba cylinder cylinder (figure (figure 4-2). 4-2). The air surrounding surrounding the earth at sea level is com pressed by the weight of the air air above it. In other words, the air at sea level is denser denser than the air air at higher higher levels.
The human eye is designed designed to to focus light light rays in air. air. This is is why objects objects appear appear blurry blurry when you open open your eyes under water. The mask allows you to put an air air space in front of your eyes to see see without without the blur. blur. As light light rays pass pass from air air to water, water, they slow down and bend. This bending is called called refraction and it changes the way you see objects under water. Objects appear 1/3 closer and larger larger than they they do in air. air. Objects are actually further further away away and smaller than the they y appe appear ar L L k J to be under water. Remember this when you are report ing the sighting of an anima animall or an object. As a new diver, you will find that you reach in front of an object object until until you learn to comp compen ensate sate for refraction.
I n tht h e W a t e r
Colors
Water cannot be significa significantly ntly compresse pressed. d. When pressure is applied applied to water, the pressure is transmi transmitted tted throughout the the water. water. The density of water at any depth depth is the same as the density of water at the surface, surface, though the pressure ressure it is under wil willl be greater because because of the weight of thewater above it. But But water is about 800 times times denser nser than air. air. This and other factors have several effects on us as divers. Water affect affects s our vision, our ability ability to distinguish
Colors also look much different underwater. underwater. Sunlig Sunlight ht is compos composed of a spectrum spectrum or a rainbow rainbow of visi visi ble and invisible invisible colors ranging fro from m infrared to ultrav ultravi i olet. As light light passes through through the water, the water absorbs the colors of the spectrum spectrum of the sunlight. The first visi visi ble color color to be absorbed is red, red, followed followed by orange, tthen hen yellow, then green, green, then then blue, then indigo, and final finally ly violet. violet. At greater greater depths, the only colors colors you can see see without without a dive ligh lightt are blues and purples.
El
El
Full
Empty
F IGI G U R E 4 - 2 . A I R H A S W E I G H T A S Y O U C A N S E E B Y T H E D I F F ER ER E N C E I N W E IGI G H T B E T W E E N A N E M P T Y A N D F U L L SCUBA CYLINDER.
NAU I Scuba Sc uba D i ver
F IGI G U R E 4 - 5 . S U U N D T R A V E L S F A S T E R I N W A T E R T H A N I N A I R . F IGI G U R E 4 -3- 3 . T H E C O L O R S S E E N W I TH T H N A T U R A L LIL I G H T A R E M U T E O .
F IGI G U R E 4 - 4 . A R T I F ICI C I A L LIL I G H T A L L O W S Y O U T O S E E T H E T R U E COLOR OF OBJECTS UNDER WATER.
If you take a dive light light with you on your dive, and shine it on objects at depth, you will will be amazed at the colors colors you will ill see. Most underwater underwater photographs are made with artifi artificia ciall light light (an electronic flash or strobe strobe)) to bring out the magnificent, true colors of the underwa ter world (figure (figures s 4-3 and 4-4).
Hearing Noises Noises sound different underwater than than they do in air. In air, you can tell where a sound sound is coming from because the sound waves hit hit one ear sli sligh ghtly tly before the other. Although the the time difference is very very short, short, it is
enough for your mind to tell and be able to locate the source of the sound. Because of of the greater density of water compared to air, air, sound waves travel travel about four times faster in water than they they do in air. air. The sound sound waves move so quickly that it it is diff difficu icult lt to determine th the e source source of a soun sound. You can hear the sound getting louder or softer, but you cannot tell its direction. When you you hear a noise, noise, you you must look all all around around you to see where the noise is com ing from (figure (figure 4-5). 4-5). Boat motors, propellers, propellers, and jet skis skis have distinctive sounds underwater. underwater. If you want to surface, but hear a boat or jet ski, stay stay under as long as safely possible or until until you hear the boat or jet ski ski leaving leaving the area. fla g and stay Remember to always fly a diver down flag within within its perimeter to to avoid surfacing surfacing in the same area as a boat or jet ski.
Heat Loss When When the the air is 27°C (80 (80°F), °F), you you think it is warm and comfortable. comfortable. When you jump into 27°C (80 (80°F) °F) water, the water also feels comfortable at first, first, but you will notice you start to feel chilled if you remain motionless for a short time. Because water is much denser than air, air, water can absorb a great deal of heat without changing changing its temper ature. Also, heat can be conducted out of your body by direct direct contact with water at a rate nearly nearly 25 times faster than by air.
Chapter 4- Diving Science
Your body is transferring transferring heat to the water touching touching your your body to try to get the water as warm as you are. When your body body is drained of enough heat, you will will be chilled chilled and start to shiver. Shivering Shivering is your body’s body’s sig nal nal to tell you that it can can no longer genera generate te enough enough heat to keep your intern internal al organs warm. When you start to shiver on a dive, you must end your dive and get out of the water to rewarm.
m
□
Have you you ever tried to run iin n water even up to your waist? If so, you know how diffic difficult ult it is compared compared to running running in air. air. The water resists your movem movement. This resistance to movement is called called drag. Drag is some thing that that you must must deal with when diving. The total frontal frontal area of your body body and equipment equipment and its surface configuration configuration also affect your resistance resistance to movement in the water. water. If your equipment is sleek and compact, compact, it wil willl be easier for you to swim than if if your gear has dangli dangling ng hoses and loose straps. The more mo re you can streamline streamline yourself yourself and your equipment, equipment, the easier it wil willl be for you to move through the water. water. If you are in a horizontal horizontal position, position, you have much much less resistance resistance to forward movement ovement than if if you are in in a semi-upright semi-upright position (figur (figure e 4-6). 4-6).
F IGI G U R E 4 -6-6 . S T R E A M L INI N I N G Y O U R E Q U I P M E N T A N D Y O U R S E L F M A K E S IT MUCH EASIBI TO MOV E THROUGH THE WATER.
I lel e r l lyl y W l i a t Y o u H a v e L e a r n e d Review the followi following ng questions about density density and its effects: 1. Air is approximately oxygen and 78% . 2. True or false: Air is denser denser in the mountains (at altitude) than at sea sea level. 3. True or false: Water is denser at 30 meters (99 feet) than than it it is at 3 meters meters (10 feet). 4. One way you can reduce drag unde underr water is is by ____________
5. When you look at objects under water, water, they appear and than they really are. are. 6. True or false: Sound travels slower under under water. ________________________
__________________
BUOYANCY When different different objects are placed in water, some float float,, some sink, sink, and some remain remain suspended between the surface and the bottom bottom. These objects objects all all have vary vary ing densities and this affects their their buoyancy. By under standing buoyancy, you can control it to your advantage for diving.
A r c h i m e d e s P r i n c i p l e Archimedes, a Greekphilosopher, noticed that that the level of water in a tub ros rose e when he sat in it. From that observation and other experiments, experiments, he found found that an objec objectt in a flu id is buoyed up (lifted) (lifted) by b y a force equal to the weight of theflu fl u id it displac displaces. es.
E l
NAUI Scuba Diver
F IGI G U R E 4 -8- 8 . Y O U W A N T T O F L O A T,T , O R B E B U O Y A N T W H E N Y O U A R E A T T H E S U R F A C E .
F IGI G U R E 4 - 7 . B U O Y A N C Y I S AL AL W A Y S A N U P W A R D F O R C E T E N D I N G TO CA USE YOU TO FLOAT, RISE, HOVER, OR SINK LESS QUICKLY.
If you weigh the water that overflow overflows s and the ping-pong ball, ball, you find find that that the water weighs more more than the ping-po ping-pong ball. ball. If an object displaces an amount of water weighing more than it does, it floats. If an object displaces displaces an amount of water weighing less less than it it does does,, it sinks. sinks. If an object object displaces displaces an amount amount of water weighing weighing the same as it does, it it hovers.
S t a tet e s o f B u o y a n c y Buoyancy Buoyancy is always always an upward force tending to cause you to float, float, rise, hover, or sink less quickly quickly (figure (figure 4-7). As a diver, you control your buoyancy prima primaril rily y by the the amount of weight you wear and the amount amount of air you you |L n have in your your buoyancy compensator pensator (BC (BC)) or dry suit.
Positive F IGI G U R E 4 -9- 9 . Y O U W A N T T O B E N E U T R A L L Y B U O Y A N T D U R INI N G Y O U R D I V E .
You can observe observe displacement by fill fillin ing g a glass to its brim with water. water. If you push push a pingping-pon pong g ball into the glass, glass, the water runs over the side. The volume or or amount of water that overflows the glass is the volume that has been displaced displaced..
If an object floats, it means means the object object displaces displaces an amount of of water that weighs more than the object does. In other words, words, the object is less dense than the water. You want to have enough buoyancy to float when you are at the surface before before and after you dive (fig (figure ure 4-8). 4-8).
Neutral If an object is neutral, neutral, it it hovers. hovers. This means means the object displaces displaces an amount of water th that at weighs the the
Ch apter 4- Diving Diving S cienc e
IjTj
same as it does. You want to be neutra neutrally lly buoyant throughout throughout your dive (figure (figure 4-9). 4-9).
Negative i v i n g
If an object object displaces displaces an amount of water that weighs less than the the object does, it sinks. Because the object is denser denser than the water, the water does does not pro vide sufficient sufficient buoyancy to to make it hover or or float. You want to overcome any buoyancy you have when you begin your dive to be able to get beneath beneath the surface.
S c i e n c e
Factors Affecting Buoyancy Your weight and your volume affect your buoyancy. Your weight includes includes the weight of your body and the weight of your gear (divin (diving g suit, weight belt, and scuba unit) nit).. Your volume depends on your body size, size, the thickness of your diving diving suit, and your gea gear. r. Remember, Remember, density is mass mass per unit unit volume. Wetsuits are muc much h less dense than water water because of the thousands of nitrogen nitrogen gas bubbles trapped in the neoprene material. If youwear a full full 6 mm thick wetsuit wetsuit andjump in the waterwithout without any other gear, it wil willl be impossible for you tosink belowthe surface. You cannot dive with a heavy wetsuit and a standard 12-liter 12-liter or 80 cubic foot aluminu aluminum m cylinderwithoutwearing additional weigh weights. If you can imagine making a dive in a wetsuit, wetsuit, you can begin to understand how your buoyancy changes over the course of a dive. Asyou descend, the pressure of the water increases increases and compresses the gas bubbles in your your wetsuit. As the bubbles compres compress, the wetsuit wetsuit dis17^1 places less water and therefore, therefore, loses some of its buoyancy (figure (figure 4-10). 10). You will notice that you you are sinking faster and faster the deeper you go. To compensate for the loss of buoyancy, buoyancy, you must add air to your BC, which which increases increases your volume to rregain egain the lost buoyancy. buoyancy. As you ascend at the end of of your dive, the bubbles in your wetsuit wetsuit and the the air air in your BC will will expand expand because because the pressure pressure of the water is reduced. You will will notice that you are rising faster and faster. To compen compen sate sate for the additional buoyancy, buoyancy, you must vent ai airr from your BC to control control your ascent. Uncontrolled Uncontrolled X ascents are extremely extremely dangerous.
F IGI G U R E 4 - 1 0 . A S Y O U D I V E , T H E P R E S S U R E C O M P R E S S E S Y O U R W E T S U ITI T A N D M A K E S Y O U L E S S B U O Y A N T .
The density of the the water in which you dive also affects your buoyancy. Salt Salt water is about 2.5% denser than fresh water becaus because of the weight of the minerals minerals dissolved in it. it. Therefore, you displace more weight in salt water water than in fresh water, soyou have greater greater buoy buoy ancy in salt water. If you are weighted to be neutral neutral in salt water and you dive in fresh fresh water with the same amount of weight, you will ill sink. You must must recheck recheck your buoyancy if you change from from diving diving in salt water to fresh water and vice versa. As a diver, you you usually usually want to avoid having so little buoyancy that you mustwork to mainta maintain in your your depth depth or to keep eep from sinking (figure (figure 4-11). 4-11). Neutral buoyancy beneath the surface is your constant constant goal, and it is is important to help help protect protect marine life. Divers who land,
m
19I
F IGI G U R E 4 1 2 . T H E A V ER ER A G E P E R S O N C A N F L O A T M O T I O N L E S S A T T H E S U R F A C E W I TH TH T H E I R L U N G S F U L L O F A I R .
F IGI G U R E 4 1 1 . I T I S A C C E P T A B L E T O K N E E L I N S A N D , B U T I T ISIS N O T A C C E P T A B L E TO T O K N E E L O N C O R A L , O R O T H ER ER UNDERWATER CREATURES.
sit, or stand on on coral reefs or other marine life can dam age or kill ill these creatures. Diving Diving without buoyancy control is tiring, tiring, hazardou hazardous, s, and a sign of an unskilled, unthinking, unthinking, and uncaring uncaring diver. diver.
Buoyancy Checks Different people have different different amounts of personal buoyancy. Some people people float higher, higher, some float lower, lower, and some peop people actuall actually y sink, even with th their eir lungs full full of air (figure (figure 4-12). You must must check to determine your buoyancy in the water. water. To check your personal buoyancy, use the following following steps, wearing wearing a bathing bathing suit in fresh water: water: 1. Assum sume a vertica verticall position in in the water. You must must remain motionless. 2. Inhal Inhale e a deep breath of air and hold hold it. If you can hang motionless motionless at any level, level, tota totally lly submerged, you are neutral. If any part part of your your head head is out out of thewater, you are buoyant. buoyant. If you sink, you are not.
[
10 0
3. Exhale Exhale the air air in your lungs. Your chest chest deflates deflates and you displace less water so you will ill start start to sink, unless you are very buoyant. 4. Kick back back to the surface. You can also also try this experiment in in salt salt water to see see the difference. difference. Your instructor instructor wil willl recommend mend how much lead weight you should should put on a weight belt based based onyour personal buoyancy and gear. The lead weights divers wear to adjust buoyancy buoyancy are many many times more dens dense than water. By selecting the right amount of weight, weight, you can adjust your buoyanc buoyancy y to be neutral neutral at depth. Before you begin a dive, you you must check to see how buoyant you are with your your gear on. on. To check your buoyancy for diving, diving, use the followin following g steps: 1. Assume a vertica verticall position in the water. You must must remain motionless. 2. Inha Inhale le a normal breath of air air and hold it. 3. Vent Vent or dump dump all of the the air air from your BC. BC. If you float at eye eye level, you are are properly properly weighted. weighted. If your head is higher higher out of the water, you are too too buoyant. buoyant. If your head is is in the water, you you are too heavy. 4. Exhale Exhale the air in your lungs. Your ches chestt deflates and you displace less water so you will will start to sink. 5. Kick Kick back to the surface and infl inflate ate your BC. 6. Change the weight weight on your your weight belt, if neces-
Chapter 4- Diving Science
sary. If you were too buoyant, buoyant, you need to add weight. If you were too heavy, you need need to take weight off your wei weight ght belt. If you change equipment equipment or if if you lose or gain weight (more than 2.4 2.4 kilograms or 5pounds), 5pounds), you must recheck your buoyancy before you start start your next dive.
Decreases
Atmosphere Atmos phere
Air Pressure
Increases
Water pressure is consistent
V e r i t y W h a t Y o u H a v e L e a r n e d Review the following following questions questions about buoyan buoyancy: cy: 7. The The three factors affecting buoyancy are
F IGI G U R E 4 1 3 . O N E A T M O S P H E R E O F P R E S S U R E I S A 6 U U T 1 B A R ( 1 4 . 7 P S I)I ) .
and 8. You can change change your buoyancy by or 9. An ocean diver needs needs to. weight to dive in fresh water. water. 10. During During descent, a diver diver’s ’s buoyancy buoyancy tends to
posed of mostly fluid fluids, s, which which cannot be compressed. Second, most air air spaces in your your body, such as your lungs and sinuses, are open to the surround surrounding ing atmosphere and its pressure. As long as the pressure in a body’s air air spaces matches the surrou surroundin nding g atmospheric atmospheric pressure, the pressure is equalized equalized and you do not feel any any effects from your surroundi surrounding ng atmospheric pressure.
F r e s h W a tet e r
WHAT IS PRESSURE
3
When you descend in water, the force from the weight of the air and water above you affects affects you. you. This force is called called pressure pressure and is measured measured in bar or pounds per square square inch inch (psi (psi). ).
flip If you weighe weighed d a column of air air that was 1centime 1centime ter by 1centimet 1centimeter er and extended all all the way to the edge of the atmosph atmosphere, you would fin find d that that it it weighed about 1kilogra kilogram. m. If it were ere 1inch 1 inch by by 1inch, 1inch, it would would weigh weigh about 14.7 pounds. In other words, this colum column n exerts a pressure of about 1bar 1bar or 14.7 pounds per square inch inch (psi (psi). ). This constant pressure pressure is called 1atmosphere of pressure (figur (figure e 4-13). This atmosphere osphere of pressure ssure is constantly constantly pushing on your body from all all directions. However, ever, you usually usually do not notice it it for two reasons. First, First, your your body is com-
If you took a column of fresh water that was 10.3 meters (34 feet) tall tall and weighed weighed it, you would also see see that it it exerted a pressure pressure of about about 1bar 1bar (14.7 psi). This This equals equals the pressure exerted by the atmosphere atmosphere at sea level. Therefore Therefore,, 10.3 meters ters (34 feet) of fresh water i & i i is also equivalen equivalentt to 1atmosphere of pressur pressure. e. Because water is not compressible and transmits pressur pressure e freely, pressure pressure in water increases at a constant rate, and pressure pressure is cumulativ cumulative. e. In other words, 10.3 meters (34 feet) feet) of of fresh water is is 1atmosphe 1 atmosphere, 20.7 meters (68 (68 feet) of fresh water water is 2 atmosphere, 31 meters (102 feet) of fresh water is 3 atmosphere, and so on.
Sail Water If you took a column of of salt water that that was 10 meters (33 feet) tall tall and weighed it, you would also also see that that it exerted a pressure of about 1 1bar bar (14.7 pounds per square inch inch). This This equals the pressure exerted by the atmosphere at sea sea level. Therefore, 10 meters (33 feet) of [T ^ l seawater seawater is also equivalent equivalent to 1atmosph atmosphere ere of pressu pressure. re. LbUJ
NAUI Scuba Diver
i c n e i c S
Because atmospheric pressure pressure is nearly nearly constant at sea level, most div diving ing depth gauges (pressure (pressure gauges) are adjusted or calibrated to read zero at at sea level. When a depth gauge indicate indicates s 10meters (33 feet) in salt salt water, it is saying that that the pressu pressure re is 1atmosphere greater than it it was at the surface. The pressu pressure re on such pressuree because it ignores the a gauge is called gauge pressur 1atmosphe atmosphere from the air air above above the the water (fig (figure ure 4-14). You always use absolute pressure when determining determining the total total pressure being exerted on your body at any any depth. For For example, if if you descend from the surface to 10 meters meters (33 feet) of salt water, you are doubling doubling the m pressure on your your body. If you continue continue to 20 meters (66 feet), feet), you are are triplin tripling g the pressu pressure re on your body. As a diver, diver, you must be concerned with with pressure and how it can affect the volume of your air air spaces under under water. water.
= 3 CO CO
0
Q. 0
O
g n i v i D
CO
.O
CO
0 CO
Q.
C O B co o
o
1 atm (Gauge Pressure)
V e r i f y W h a t Y o u H a v e L e a r n e d
* *
F IGI G U R E 4 1 4 . W A T E R P R E S S U R E A L O N E I S C A L L ED ED G A U G E P R E S S U R E . W A T ER ER P R E S S U R E A N D A T M O S P H E R I C P R E S S U R E C O M B I N ED ED A R E C A L L E D A B S O L U T E P R E S S U R E .
Because water is not compressible and transmits transmits pres surefreely, pressure pressure in water increases at a constant rate, and pressure is cumulative. cumulative. In other words, 10meters (33 feet) of salt water equals 1atmosphere, 20 meters (66 feet) of salt salt water equals 2 atmosphe atmosphere, 30 meters (99 feet) feet) of salt salt water equals 3 atmosphere, and so on.
Units of Pressure You can refer to pressure pressure in two different ways ways:: absolute and gauge. gauge. When you dive, the pressure pressure of the water as well well as the pressure of the atmosphere push on you. At sea level, you are already under 1atmosphere of pressure absolute (a (ata). ta). At a depth of 10 meters (33 feet), feet), you are under under 2 atmosphere of pressure absolute: 1atmosphere sphere from the the air air plus plus 1 atmosph atmosphere ere from the salt salt water. At 20meters (66 feet), feet), you are under under 3 atmosphere sphere of pressure absolute absolute (ata (ata): ): 1atmosphere sphere from the air air plus 2 atmosphere atmosphere from the salt water.
10 2
Review the follo following wing questions questions about pressur pressure: e: 11. One atmosphere of pressure is equal equal to about meters ( feet) of fresh water or meters meters ( feet) of seawater. seawater. .times greater greater at 12. The pressure pressure is is . 40 meters (132 feet) in salt salt water than it it is at the surface. 13. The absolute pressure pressure is ata at 20.7 meters (68 feet) in fresh water.
H o w P r e s s u r e A t i e c t s V o lul u m e To understand the direct direct effects of pressure, you must consider consider the effects of of pressure on an open system and on a closed closed system.
Open System If you invert invert a bucket, bucket, force it below the surface of the ocean, and and take it to depth, the pressure sur rounding rounding the bucket increases and compre compresses sses the air air in the bucket. bucket. The water level rises into the bucket. bucket. As the air air compresses, its volume decreases. decreases. No air is is lost from the bucket. When you take the bucket back to the
Chapter 4- Diving Science
VOLUME 1 0'-1 ata
VOLUME x 1 0'-1 ata Buck et is still still full full of air, air, although exce ss ■ air volume has vented off,
VOLUME REDUCED TO Va 33-2 ata
VOLUME x 1 33'-2 ata Compressed air expands and overflows bucket as pressure is reduced.
VOLU VO LUME ME x 1 66'-3 ata
VOLUME REDUCED TO Vz 66‘-3 ata
Compressed air expands and overflows bucket as pressure is reduced.
VOLUME REDUCED TO 'U 99'-4 ata
VOLUME x 1 99'-4 ata Compressed air is added to open system at depth.
—
OPEN SYSTEM DESCENT F IGI G U R E 4 1 5 . A S T H E P R E S S U R E O N A IRI R I N C R E A S E S , T H E V O L U M E D E C R E A S E S .
OPEN SYSTEM ASCEN A SCENT T F IGI G U R E 4 - 1 6 . I F Y O U F I L L A N O P E N B U C K E T W I TH T H A I R W H I LEL E A T D E P T H , T H E A IRI R E X P A N D S A N D B U B B L E S O U T O F THE BUCK ET AS YOU BRING THE BUCKET BACK
surface, the pressure decreases, and the a air ir expands to its original volume. When the bucket bucket gets to 10 meters (33 (33 feet) feet) of sea water or 2 ata, the pressure has doubled on the bucket. The volume of air air in the bucket bucket has decrea decreased sed to half half of the original original surface volume. When the bucket desce descends to 20 meters (66 feet) feet),, whic which h is 3 ata, the pressure has has tripled tripled on the the bucket bucket and the volume of air in the buck et will have have decrea decrease sed d to a third of the original original surface surface volume (figure (figure 4-15). This inverse relationsh relationship ip between pressure and vol Boyle’s Law, which is named for the ume is known as Boyle’ scientist who first first recognized the relations relationship. hip. Knowing the name of the law is not as importan importantt as understanding the concept concept of the relati relationship onship between pressure and vol vol ume. When one increases, the other decre decreases, if it it can. Now Now conside consider a situation situation where you you have the abilit ability y to maintain the volume of air in the bucket bucket during its descent. Asyou take the bucket to depth, you add air air to the bucket through a hose. You keep the volume volume constant by adding adding enough air to match the origi original nal volume. volume. You take the bucket to 10 meters (33 feet), feet), fi fill it it with air, air, and raise it to the surface. surface. As the pressu pressure decreasesfrom 2 ata to 1ata, the volume of air air
TO THE SURFACE.
doubles. The bucket cannot cannot hold this increased volume, volume, so the excess air bubbles out around around the rim of the bucket. If you took the bucket to 30 meters (99 feet), feet), filled filled it with air, air, and then then raised raised it to the the surface, surface, a vol ume of air air equal equal to 3 buckets buckets would escape and the vol vol ume equal to one one bucket bucket would remain remain (figur (figure e 4-16). 4-16).
C lo s e d S y s t e m The effects of pressure on a closed closed system can be much more dramatic. If you take a sealed sealed plastic plastic bag filled filled with air air down to depth, depth, the bag becom becomes smaller smaller and smalle smallerr as the air air compress compresses and the the volume decreases. When you return return the bag to the sur face, the air air expands expands and the volume increases back back to its origina originall size size (figure (figure 4-17). 4-17). Now imagine imagine that that you you take the same bag down down to depth depth, open open it, fil filll it with air air back to its its origina originall volume, volume, and close it again. again. When you bring the bag back to the surface, the air air expands, ands, but it cannot escape because because the bag is sealed sealed.. The bag bag will ill expand expand slightly, but will will final finally ly burst to releas release e the expanding expanding air (figure (figure 4-18). 8).
NAU I Scuba Sc uba D i ver
VOLUME 1 0'-1 ata
VOLU VO LUME ME x 3 0'-1 ata Bag ruptures! ruptures!
Y\ J /
VOLUM VOL UME E 1/2 ,\'/ ,\'/ 33 -2 ata
VOLUME x 1 1/2 33-2 ata ata Bag begins to expand. expand.
'
VOLUME Va ;'' V 66'-3 ata v
V J\
CLOSED SYSTEM DESCENT
\
VOLUME VOLUME x 1 66'-3 ata Compressed air is added to bag at depth and bag is sealed.
CLOSED SYSTEM ASCEN A SCENT T
/
Since no air is added to system, the volume of the bag shrinks.
F IGI G U R E 4 1 7 . A S T H E V O L U M E D E C R E A S ESE S INI N A C LO LO S E D S Y S T E M , T H E FLEXIBLE CONTAINER ALSO DECREASES IN SIZE.
F IGI G U R E 4 1 8 . I F Y O U A D D A IRI R T O A C L O S EO EO S Y S T E M A T D E P T H A N D T H E N A S C E N D W I TH T H I T,T , T H E F L E X I B L E C O N T A I N E R WILL BURST TO RELEASE THE EXPANDING AIR.
m
C D
The only way to prevent prevent the bag from bursting is is to vent the excess air air from the bag duri during ng its ascent. The same thing would happen happen to your lungs if you took a deep breath from from a scuba regulat regulator or at depth, held held it, and then swam toward the surface, even at a few feet below the surface. You must NEVER hold your breath when breathing compressed air under water.
The greatest change in pressure is between the sur face and 10 meters (33 feet) when you you are divin diving g in salt water or the surface and 10.3 meters (34 feet) feet) when when you are diving in in fresh water. water. The pressu pressure doubles doubles from 1 ata to 2 ata. As you read further on in this chapter, you will ill learn learn how this change in pressure affects your body’s air air spaces.
H o w P r e s s u r e A f f e c t s D e n s i t y The increasing increasing pressure pressure under water not only affects the volume of air, it also also affects the density of the air. As the pressure increases, the air air compresses to a smaller smaller volume. volume. As the air air compresses, it it becomes denser. At 10 meters (33 feet) or 2 ata, air air is twice as dense as it is at the surface. At 20meters (66 feet) or 3 ata, air is is three
times as dens dense e as it is at the surface surface (figure (figure 4-19). 4-19). This explains why why you use air faster when you dive deeper per and why breathing rresistance esistance increases with depth depth - you are moving denser denser air air through through your lungs lungs with each breath. When you add air air to your lungs lungs from scuba at 2 ata to maintain maintain their origina originall volume, volume, your lungs lungs contain twice as much air air in the same physical space. space. When you scuba dive to 3 ata, your your lungs now conta contain in three times as much air air in the same space compared to sea level. The overall overall effect is that the deeper you dive, the denser denser the air inside inside an air air space becomes. Those Those air spaces include your lungs, middle ears, and sinuses. sinuses. As the air air you you breathe breathe becomes denser, it does not flow as easily. easily. When you scuba dive, you breathe air that is compressed to the ambient ambient pressure at your m depth, depth, which is much denser than the air air you breathe on the surface. surface. The deeper you dive, the the more resistance there is to the flow of compre compresse ssed d air air through your regu lator lator hose (and through your air air passages). passages). This resist ance makes makes it mo more re diffi difficu cult lt to breathe, breathe, the deeper you dive. The combined resistance resistance of breath breathing ing compressed
Chapter 4- Diving Science
H o w P r e s s u r e A fff f e c t s A i r C o n s u m p tit i o n Density x 1 0'-1 ata Density x 2 33'-2 ata Density x 3 66-3 ata Density x 4 99-4 ata
F IGI G U R E 4 1 9 . T H E D E N S I T Y O F A IRI R INI N C R E A S E S A S T H E PRESSURE INCREASES.
air air and the restrictions restrictions of the equipme equipment nt you wear to dive puts puts limitatio limitations ns on how hard you can exert yourself while while under water. water. You can function almost almost normally normally while while under the pressure of water. To be comfortable, comfortable, you must keep the pressure in the air air spaces inside your body equal to the pressure surroundi surrounding ng your body. One of the importan importantt less lesson ons you you will will leam in in your NAUI Scuba Diver certifi certifi cation cation course is how to equalize pressure under water.
V e r i f y W h a t Y o u H a v e L e a r n e d Complete the following following chart chart for a given quantity of air in a balloon: balloon: Pressure
Volume
Density
Doubles
Halves
Doubles
One third Halves Quadruples
The deeper you dive, the great greater er the surrounding surrounding pressure. The greater the surroun surroundin ding g pressure, the denser the air air that that you breathe and the faster you empty empty your cylinder. The rate at which you consum consume e the air in your your cylinder cylinder is directly directly proportional to the the depth depth of of your dive. You consum consume your air air twice twice as fast at 10 meters (33 (33 feet) as you do on the surface, three times as fast at 20 meters (66 feet), and so so on. This is readily readily seen by considering considering these depths depths as multip multiples les of of atmos pheres of pressure.
A i r C D n s u m p t i s n F a c t o r s Other factors also affect the rate at which you con con sume air air on your dive. These factors include: include: • Your activity activity level during the dive. dive. • Your menta mentall state. • Your body size. • The warmth of your d diving iving suit. • Your level of physical physical fitness. Besides Besides depth, depth, physical physical activity activity has the greatest greatest effect effect on your air air consumption under water. water. You can use up to 4 times more air air when you are exerting yourself yourself than when you are resting. resting. Improving Improving your air consumption is not the only reason to avoid exertion under water, but it is certa certainly inly one that good gooddivers keep in mind. Beginni Beginning ng divers tend to be more active than than neces neces sary, but they quickl quickly y learn learn how to relax under water. During the first few dives dives after training, training, a new diver’s air consumption rate decreases significantly because they learn learn how to relax. With With experience, experience, these these divers also leam how to to move move through the water more efficiently efficiently.. The sooner sooner you can do this, the more enjoyable your diving will be. As a diver, you need to to think think about developing developing a slow and relaxed breathing pattern as well as a slow rate of breathing. When you swim fast under water, water, you breathe more deeply and more often. often. Therefore, you use use more air. air. You can waste waste a lot of air if if you you brea breath the e shallowly and and rapidly. rapidly. If you limit limit your exertion exertion and relax during your dive, you will will be able to maintai maintain n a slow, deep pattern of breathin breathing g with
NAUI Scuba Diver
long inhalati inhalations ons and long exhalations. exhalations. This is the best way to breathe under water. Anothe Anotherr factor in air air consumption consumption is your physical size. Larger people have larger larger lungs and use use more air than smaller smaller people who have smaller smaller lungs and small small er overall overall metabolic metabolic needs. To compensate for these dif dif ferences, som sometim etimes larger divers wi willll use use larger cyl cylin in ders. There is usually usually no reason reason for a small person person to carry carry the same size tank as a larg larger er person unless it is needed for a specific specific purpose. Body temperat temperature ure also affects your breathing. The colder you are, the more more you breathe. breathe. This is unfortu unfortu nate because heat is also lost each time you exhale. Therefore, you need to be sure to wear the the proper amount of insulatio insulation n for the conditions. Divers who are physical physically ly fit fit breathe less less and use their their air air more more efficiently. efficiently. They also do not not have to oxy genate excess body fat. fat. These factors, or combinations combinations of of these these factors, can signific significantly antly affect your breathing rate under under differ ent conditions. Through experience, xperience, you you will ill learn to estimate the amount of air air you will will use base based d on all all these factors. factors.
M o n i tot o r ini n g A i r C o n s u m p t i o n
□
Most sport divers do not calculate calculate their air air consump tion tion beforeeach dive. Instead, as they gain experience div ing, they keep a record in their their logb logbooksof how long their their air air lasts at different depths and in different conditions. This enables them to make rough predictions of of the time they will ill be able todive at a given depth, basedon their their air air sup ply. They monitor thei theirr submersible pressure gauges, dive timers, and dive computers and use the informatio information n from these instruments to determine when to begin their their ascent. Even if you calculate calculate your air air consump consumption tion mathe matically, matically, which is possi possible ble,, any combination of the the air air consumption facto factors rs can change your predicted predicted air air con sumption rate. rate. If you work harder than planned or the water is colder than you thought, your air air consumption rate will will be affecte affected. In certain specialty areas of of diving, it it is essential essential that you predict your air air consumption to avoid running out of air. This is especially especially important if you participate
in deep diving, cave or cavern diving, or wreck wreck diving. Anyone Anyone who participates participates in this type of diving must know how much air air they will ill need for any given dive. Your rate of air consumptio consumption n will will change change quite a bit during during the first first 10 or 20 dives you make. Recording Recording every dive in your your logbook will ill help you to estimate how how long your air air wil willl last on most most dives dives at different depths. Be sure to record the size of cylinde cylinderr you use on each dive if you use different size cylinders. This is is a good practice practice to continue continue even beyond your early early dives, because you will will learn learn how much your usual rate is affected affected by exertion, temperature, and other factors. You will ill also also be able to estimate not not only the duratio duration n of your air air supply for a given depth, depth, but will will be able to adjust it for for other factors as well. well.
V e r i f y W i i a t Y o u H a v e L e a r n e d Review the following following questions about air air consumption: 14. Two factors that affect your air consumption rate under water are and _____________________________
15. Divers monitor thei theirr air air supply under water by checking their
Y O U R B O D Y When you dive, the pressure of the water affects your air air space spaces s as well well as your breathing.
How Pressure Affects Your Air Spaces The air air spaces spaces in your body include include your lungs, sinuses, and middle ears. You can also have ai airr spaces in your your stomach, stomach, intestines, and teeth (figur (figure e 4-20). There are also two air air spaces outside your body that you need to consider when diving diving.. Those are your mask mask and dry suit (if (if you are wearing one). Pressure Pressure can affect these spaces in drama dramatic tic ways, called called the direct direct effects of of pressure.
Cha pter 4- Diving Diving S cienc e
M id d le E a r The air air spacesinside your middle ears are especially especially important when you dive. dive. You must be able toequalize the pressure inside your ears to comfortably and safely dive. i v i n g
A n a t o m y
F IGI G U R E 4 - 2 0 . T H E A I R S P A C E S INI N Y O U R B O D Y I N C L U D E Y O U R LONG S, SINUSES, AND M IDDLE EARS. YOU CAN A L S O H A V E A I R S P A C E S I N Y O U R S T O M A C H , I N T E S TINES, AND TEETH.
Squeezes
m
When you descend, the pressure on your your body increases at a rate of about 0.1 bar per meter or about 0.5 psi per foot of depth. depth. If any air air space in your body is closed off so that the pressure inside inside the air air space cannot cannot stay equal equal to the surrounding surrounding pressure, the surrounding surrounding pressure tries to compress the air in the air air space. Whenever the pressure outside an air air space is greater than the press pressure ure inside an air air space, the situation situation is calle called d a squeeze and it can can cause damage to your body. Doctors also call this type of injury a barotrauma, pressuree injury. injury. which means pressur Divers can experience many different different types of squeeze. You must be specif specific ic when you discuss this this type of condition. For example, you can get squeezes in your your sinuses, middle ear, or mask. You can avoid each of these squeezes by using proper equal equaliza izatio tion n techniques. techniques.
S c i e n c e
Your ears are divided into three sections: sections: the outer outer ear, the middle middle ear, and the the inner ear (figu (figure re 4-21). 4-21). The outer ear is your ear cana canal.l. The eardrum separates your outer ear from your middle ear. The eardrum eardrum is a flexi flexi ble membrane that vibrates vibrates when sound sound waves waves hit hit it. Your middle ear co contains ntains a series series of three three small bones that that transmi transmitt sound waves from the eardrum eardrum to the inner ear. Your middle middle ear also also has has an airway link link ing it to the the back of your throat. This airway airway is called Eustachi chian an tube. Your middle ear transmits sound the Eusta sound waves from your eardrum eardrum to the audito auditory ry nerves of your inner ear. Your body’s balance mechanism is also contained contained in the inner ear. If you have a sudden sudden change in pres sure or temperature in one ear and not the other, you can get dizzy or experience vertigo.
M id d i e E a r S q u e e z e s A middle ear squeeze eze occurs when the air air or or water pressure pressure in your outer ear is is greater than the a air ir pres sure in your middle ear. You equalize your middle ear by moving moving air air from your throat through the the Eustachian Eustachian tube into your middle ear. For most most people, equalizi equalizing ng the pressure pressure inside their their ears is not an automatic automatic proce process. To pass pass air through the the Eustachian Eustachian tube tubes s usually usually requires requires a deliber ate action to open the tube tubes and allow allow air air to flow through them them. If you cannot equalize equalize your ears ears during a dive, dive, you must must end the dive and return to to the surface. surface. V r / As you descend in the water, the pressure on your outer ear increases increases and pushes in on the the eardrum. If the pressu pressure re continues to increase and is not equalized in the middle middle ear by passing passing air through the Eustachian tube, tube, pain wil w illl be felt; and the eardrum eardrum flexes in to help equalize the pressure. pressure. Fina Finally lly,, the eardrum can rupture rupture /
Blocks A reverse block is is the opposite opposite of a sque squeeze. It occurs when the pressure inside an a air ir space is greater than the surrounding pressure. ssure. Blocks can occur during ascent. Air is trapped trapped inside an air air space space and the air tries to expand as the surround surrounding ing pressure decreases.
T
\
10 7
NAU I Scuba Sc uba D i ver
Oval Window
Ear Drum
Window
Nerves
Cochlea (Hearing Organ) Tube to Throat
F IGI G U R E 4 2 1 . T H E M I D D L E E A R S P A C E ISIS C O N N E C T E D T O T H E T H R O A T R Y T H E E U S T A C H I A N T U B E . A I R P A S S E S T H R O U G H T H ISI S T U B E T O E Q U A L I Z E P R E S S U R E I N T H E M I D D L E EA EA R .
to allow allow water to flow into the middle ear to equalize the pressure. BEFORE you feel the slightest pressure in your ears, you need to equalize. The Eustachian tube opening in the throat is normal flexing flexing the ly closed. closed. Most people can open the tube by the muscles at the the back of of their throat or jaw. If you listen closely, closely, you can hear a slight crackl crackling ing sound inside your head when you yawn, swall swallow, ow, or move your jaw jaw forward. Some divers are fortunate and can equalize or clear clear their ears by swallowing swallowing or wiggling wiggling their jaw. Most divers require require a bit more effort effort to open the tube and equalize equalize the pressure. pressure. The most common method for equali equalizin zing g pressure in the middle ear is simple. You close close your mouth mouth tight ly or block it with your tongue tongue (on (on scuba), close close your nostrils by pinchin pinching g them them shut, and then exhale light lightly ly (figure (figure 4-22). As you build a slight slight pressure in your head, you should should hear the the pressure open the tube with with a
F IGI G U R E 4 2 2 . T H E M A N E U V E R M O S T C O M M O N L Y U SE SE D FO R EQUALIZING THE PRESSURE IN YOUR EARS IS A SIM PLE BLOWING EFFORT.
gentle pop, which signals that air has flowed into the Eustach Eustachian ian tube. tube. You must never force this technique. You could seriously seriously damage your ears. This maneuver works well well for most divers. The key
Chapter 4- Diving Science
FIGURE 4 23. IF YOU DES CEND TOO FAR WITHOU T EQUALIZING, YOU M I G H T H A V E T I G H T L Y C L O S EU EU E U S T A C H I A N T U B E S .
®
to successfu successfull ear equalizat equalization ion is to keep keep the pressu pressure re dif dif ference between the water and the mid middle dle ear ear to a miniminimum. This means that you must equalize early and often, starting at just beneath the surface.
If the pressure ssure difference betw between een the inside of your ear and the water becom becomes marked, the pressure will ill hold the the Eustachian Eustachian tube closed closed (figur (figure e 4-23). 4-23). Once this happ happen ens, s, it is unlikely unlikely that you can do anything at that depth depth that will will open open the tubes. bes. Your better choice is to ascend a few feet and reduce reduce the pressure difference difference l | X j until the tub tubes will open open, and then attempt attempt to equalize again. In some cases, divers will ill need to return to the the surface and start th their eir descent from the beginning. Never try to equali equalize ze pressure in a squeezed ear by performing performing forceful forceful blowing. blowing. Blowing hard against a closed nos nose e and mouth will ill not open your Eustachia Eustachian n tubes if if they are held shut by pressure. When the the tubes are closed by by pressu pressure, they can act actua ually lly seal tighter when you blow harder. harder. This This increases the pressure pressure on your inner ear, which can permanently damage damage your hearing. Never Never try to force the Eustachia Eustachian n tubes open open by by blowing hard. It is much better to equalize your ears continually during during descent than it it is to repeatedly repeatedly descend too far, far, have trouble equalizing, and have to rise a few feet in the water. Most divers have no problem if they begin equalizing equalizing just beneath the surface and then equalize r ^ i continually on des descent. Desce Descend nding ing feet feet first also makes akes L n J equalizing equalizing much much easier easier for most ost peop people. le. Always
©
©
remember to equalize early and often!
Some other techniques you can use to equalize equalize
your ears while closing closing your your nose and mouth include include wigglin wiggling g the jaw, tiltin tilting g the head from side to side, and putting putting your tongue to the the roof of your mouth and com com press press the trapped trapped air air with with your tounge. tounge. Any of these methods are acceptable acceptable and should should help to keep the pressure pressure in your your ears equalized. If an eardrum ruptures ruptures because ecause you you carelessly ignored the the pain pain that that signals an ear squee squeeze ze,, water will will enter your middle ear. Even if if you are diving diving in the trop ics, this water will will becolder than the temperature inside your ear. When the water enters enters your middle ear, it shocks shocks your balance mechanism and can cause vertigo vertigo (dizziness). (dizziness). If this occurs, hold on to any stable object that is close by, or hug yourself yourself toprovide stability. stability. You must allow time for the water that has entered entered your ear towarm to body temperature. temperature. This wil willl happen quickly and your sense of orientation orientation and balance balance will will return. If you do suffer suffer rupture of an eardrum, eardrum, you must surface and seek medical medical attention immediat immediately ely to mini ini mize the possibili possibility ty of infection. infection. You will ill not be able able to dive again until until your eardrum has healed healed and your doc doc tor permits you to get back in the water. Remember that this injur injury y norma normally lly only occurs occurs to divers divers who who disregard disregard pressure in the ears. If you have a head cold, you must not attempt to m dive and equalize by any method method. Equal Equalizi izing ng when you have a cold can force mucous mucous and bacteria bacteria into the © middle ear space space,, which could lead tto o infection. Using decongestant drugs drugs is not the answer. answer. Decongestant drugs drugs might be be only parti partiall ally y effective, effective, or might lose lose their effect when when you are under water, water, with a variety variety of adverse consequences. Never Never use earplugs earplugs for skin or scuba diving. diving. Earplugs Earplugs trap trap air air between themselves and the eardrum. © Because there is no way to equalize tthis his air air space, the earplugs can be driven into into the outer ear can canal al by the the sur rounding press pressure ure. This is a painfu painfull and serious injury. injury.
C O
Midd!e Ear Blocks A rever reverse se block can occur, affecting your middle ear, if your your Eustac Eustachian hian tube becomes blocked blockedwhile while you are at depth. If you begin to ascend and your ear hurts and feels “fu “fullll,” ,” stop your ascent ascent and desc descen end until until the the
10 9
■
NA UI Scuba Diver Di ver
Congested sinus
Response to a squeeze
F IGI G U R E 4-4 - 2 5 . T H E B T E C T O F A S Q U K Z E O N A S I N U S I S T O H U . T H E V O L U M E W I TH TH T I S S U E A N D B L 0 0 0 T O B H 1 A U Z E T H E P R E S S U R E .
Sinus Squeeze end Blockage
F IGI G U R E 4 2 4 . Y O U R H E A D C O N T A I N S F O U R S E T S O F S INI N U S E S T H A T M U S T E Q U A L I Z E W H E N D I V INI N G .
feeling feeling goes away. Swallow, Swallow, wiggle your jaw and start to ascend slowly. You might need to repeat this technique technique throughout your ascent. If the block doe does not equalize, and you must must surface, close close your nose and mouth and breathe in. If nothing nothing works, ascend as slowly slowly as possible. In som some cases, a block might release release quickly. If this occurs, the sudden change in your your middle-ear middle-ear pressure might might cause some dizziness. The dizziness will ill pass quickly. quickly. Remember to hold on to something if you experience vertigo.
Sinuses Your sinuses are air air cavities cavities lined lined with mucous mucous membranes and surrounded surrounded by the bones of your your head (figu (figure re 4-24). Your head has four four sets of sinuses. One set is above your eyes, and the other three sets are behind your nose and cheekbones. Each Each of your sinuses is connected connected to your nasal airway airway by an air air passage. age. Under normal normal condit conditions, ions, the passages to your your sinuses are open. However, when you have a cold or congestion due due to allergies allergies or other reasons, the sinuses sinuses will ill clog.
If air air is trapped inside a clogged sinus, and you attempt attempt to dive, you wil w illl feel feel pressure on your sinuses because the air pressure inside inside the sinus is less than than the surrounding surrounding pressure. If you continue continue to descen escend d when the pressure withi within n your sinuses sinuses is less less than the sur rounding rounding pressure, pressure, the soft tissu tissue e surrounding surrounding the sinus will ill be pushed into the sinus as the tissues react to equalize the pressure pressure (figure (figure 4-25). This is quite painf painful ul and can cause blood to flow into the sinus to fill ill it. If you cannot equalize equalize your sinus sinus normally normally during descent, it will will fil filll with body body fluids. Then, during ascent, ascent, the air in the sinus will ill try try to expand to its origi origi nal nal volume but it cannot because because of the fluid. fluid. Pressure builds builds in the sinus and pain pain results. Blood can be forced out into into your nose, mouth, or mask. A sinus block traps a air ir in a sinus cavity cavity at depth. depth. The air air tries to expand expand on ascent, ascent, but cannot, causing causing pain (figure (figure 4-26 4-26). If your sinuse sinuses equalized during during descent descent because of medication medication you had taken to clear clear your sinuses, and that medication medication wore off at dept depth, h, the openings to your sinuses sinuses would close off and trap air air inside. As you ascend, ascend, the air air in in the sinus will will try to expand, expand, pressure ssure will ill build, and you will ill feel pain. You can relieve the the pain pain by descending descending again, but if if you are runnin running g low on air, this might not not be an option. option. Try breathing in with a closed mouth and nose. If this this does not help, surface surface as slowly slowly as possible.
Chapter 4- Diving Science
gas gas while while ascending, stop or slow your ascent until until the gas works its its way out of your your system. Congested sinus under pressure
Effect of ascent
i F IGI G U R E 4 -2- 2 6 . I F S W E L L ININ G O R M U C U S C L O S E S A S I N U S W H I LEL E D I V INI N G , P R E S S U R E W I LLL L D E V E L O P I N S I D E T H E
M l If you have have an imperfect filli fillin ng in one of your teeth teeth, air air can get under the the fillin filling. g. When you descend, nd, the air in the space can compress press and cause pain in your tooth. If you continue continue to dive, dive, compressed pressed air air can fil f illl the space space in the tooth and loosen loosen the filli fillin ng or fracture fracture the tooth tooth on ascent. ascent. There is nothing you can do to equalize equalize air air pressure in a tooth. You must ascend ascend back to the surface and have your tooth examined by a dentist.
SINUS DURING ASCENT.
)
Preventi Prevention on is is the bestway to avoid avoid a sinus squeeze squeeze or block. Never Never dive when you have a cold o orr sinus congestion. Also, do not dive if you must use medica tion to open your sinuses sinuses or clear clear your your ears.
Decongestant Drug s You might think think that that the answer answer to preventing a squeeze is to take medication medication before you dive. Many sprays and tablets are avail availab able le to relieve relieve congestion. But But none of these drugs drugs are designed or tested to perform under water. The effects of any drug might might be modified under pressu pressure, and littl little e is known about the potential problems that can occur occur when medications are used under water. A drug that causes drowsiness drowsiness on the surface surface can can be worse under water. For this reason, you should consult consult a doctor who knows knows about diving diving before you use any any med ication during a dive - even any regular medication you you might be taking. Also, Also, avoid taking any medication that you know produces side effects when you use it. it.
Stomach and Intestines Any gas gas that forms in your stomach stomach or intestines during your dive dive will will expand expand during ascent. ascent. This can cause discomfort by creati creating ng pressure. To prevent this situat situation ion,, avoid avoid eating gas-producing foods before you dive. If you have problem problems from stomach or intestina intestinall
Although it might seem obvious, obvious, divers divers often forget that their their mask creates creates an air air space space attached to their their body. body. This air air space space is also affected by pressure pressure. As the water pressure increases duri during ng your your descent, the mask is pushed against your face and the air air inside inside the mask compresses. Because the mask is rigid, rigid, it compresses resses only slightly. If you do do not not add add air to your mask, mask, the the low air pressure pressure inside the mask will will cause your mask to suck tightly tightly on your face. face. The soft soft tissue tissue of your face will will squeeze into into the mask, causing causing tissue damage. This This type of injur injury y is known as a mask squeeze. Bloodshot Bloodshot eyes can result. result. You should never have this type of injur injury y because you can easily easily equalize equalize the pressure inside inside your mask. Simply exhale exhale a small small amount amount of of air through through your your nose IT ^ l into the mask every time you feel pressure pressure pulli pulling ng on your your face and eyes.
D r y S u iti t If you wear wear a dry suit, you have an air air space space sur roundin rounding g your your body. As you descend, the air inside inside the dry suit wil willl compress. To keep the suit suit from squeezing squeezing,, simply add air air to the suit using using the power-inflator valve. If you are wearing a dry suit during your training, training, your instructor will will give you you specific instructions in in the use use of your dry suit.
NAU I Scuba D i ver
V e r i l y W h a l Y o u H a v e L e a r n e d
T H E A N A T O M Y O F YO U R L U N G S
Review the follow following ing questions about squeezes and blocks: 16. Which Which air air spaces spaces in your body body are affected by changes in pressure?
Your lungs are inside large cavities within your chest. chest. When you breathe in, they inflate, inflate, and when you exhale, they deflate deflate.. Your lungs lungs consist consist of millions millions of tiny air air sacs, sacs, called alveoli. alveoli. The alveoli alveoli are surro surround unded ed by capillaries, capillaries, which are tiny blood ves vesse sels ls (figure 4-27 4-27).
Lung Overexpansion Injuries 17. What What problems might might occur occur if you attempted to dive with a cold?
18. If you feel pressure pressure on your your face when descend ing, you should 19. When the pressure outside an air air space is greater than the pressure pressure in an air air space, space, you have a condition called a 20. What are three three cons consequ equence ences of ignoring ignoring an ear squeeze?
21. What What is the most most like likely ly cause of a sinus squeeze?
___________________________
22. Whic Which h type of squeeze is the easiest easiest to prevent? 23. When the the pressure pressure inside an air air space is greater than the outside outside pressure pressure, you have a condition condition known as a
______________
.
Whenever you breathe breathe compressed air air under pres sure, you are exposed to the risk risk of a lung overexpan sion sion injur injury. y. These These injuri injuries es are rare and and most divers never experience experience them, them, but they are life threatening threatening and you must understand their their causes and how to prevent and deal with them. Under normal conditions, as you ascend, you breathe in and out in a relaxed relaxed manner. manner. You exhale the compressed air from your your lungs before it can expand as a result of the decreasing pressu pressure. If you hold your breath, you you can suffer suffer a serious serious lung injury. injury. With your airway closed, closed, the air expanding in your your lungs will cause the alveoli alveoli to rupture soon soon after they reach their full volume. There is no sensation of discomfort that warns you when this rupture is about to occur.
This type of accident most commonly commonly occurs when divers panic underwater and make a rapid ascent holding their breath. breath. One cause cause is running out of air. It is instinc tive to hold your your breath whenyou cannot breathe under under water. You must train train yourself to exhale in any any situation situation that would force you to ascendwith with no air air to breathe. A lung overexpansion injury can occur in as little as 1.1 meters (4 feet) of water and is actu actuall ally y most like ly to occur in in shallo shallow w depth depths. You must understand the importance importance of not holding holding your breath at any time while under water. If a lung overexpans overexpansion ion injury injury occurs, it is extremely serious and can be fatal. fatal. You might think think it would would be a good idea to kee keep your lung lung volume as low as possible by forcefully forcefully blow ing out all all the air air you you can during an ascen ascent. t. In reality, forcing air out during an ascent is not the best thing to do. Some small small airways in your lungs can collapse when your lung lung volume is too low and the air trapped trapped behind the collapse can expand and cause cause alveol alveolii to
C ha h a p tete r 4 - 17602673 / '
Bubbles circulation (Air embolism)
Circulation of Air Sac
Ruptured air sacs (Breath held while
Arterial Arterial
Air (Alveoli)
F IGI G U R E 4 2 7 . T H E INI N S I D E O F Y O U R L O N G S R E S E M B L E STALKS OF BROCCOLI.
E D
rupture. The best best technique is to maint maintain ain normal normal lung lung volume volume during your ascent ascent by breathing normally. As long as you breath breathe e normal normally ly during during ascent, there there is litt little le danger of suffering a long overexpansion injury. injury. It is is essential that you always breathe whenever whenever you are underwater on scuba. scuba. During your your course, course, you will leam a variety of techniques for dealing with out-of air air emergencies. ergencies. Knowing how to deal with an an out-of-air emerge emergency ncy will ill help avoid a lung overexpansion overexpansion injury. injury.
m ots Divers who smoke have have a higher risk of of suffering a lung overexpansion injury injury due to lung damage from smoking.
□
There are three general types of lung lung overexpansion injuries: injuries: air air embolism, pneumothorax, and tissue emphysema.
The most serious result result of a lung overexpansion overexpansion embolism or injury is an air embolism or arterial gas embolism
F IGI G U R E 4 - 2 8 . I F A L U N G R U P T U R E S A N D I N T R O D U C E S A IRI R I N T O THE BLOODS TREAM , IT CAN C AUSE A BLOCKAGE CALLED AN AIR EMBOLISM.
(AGE). (AGE). The wor word d embolism means plug and an air air embolism refers to a plug of air air in the bloodstream bloodstream (fig (fig ure 4-28). 4-28). The greatest danger in this situ situatio ation n is that a plug of air air will will block the the flow of blood blood to the the brain. An air embolism can cause unconsciousness, paralysis, per manent brain brain damage, and even death. It is one of the the most serious serious of all all divin diving g accidents.
Pneumothorax If a lung lung ruptures, and th the e escaping air gets into the pleural lining surrounding surrounding the lungs, lungs, the escaped pneu mothora thorax, x, air air can cause a condition condition known as &pneumo which is a collapsed lung. This is not fatal by itself, but it is painful painful,, can lead to serious serious complications, and requires immediate medical medical attention.
T isi s s u e E m p h y s e m a If air air from a ruptured lung escapes escapes into the chest chest cavity cavity below the breastb breastbone, one, it it causes a condition condition known as a mediastinal emphysema (air (air in the middle middle tis sues). In this case case,, the air is around the the heart, heart, and expansion of the air wil w illl cause pressure pressure on the the heart and the large blood vessels leading into and out of the heart.
NA UI Scuba Sc uba D i ver
This condition is obviously dang dangerou erous, s, painful painful,, and also requires immediate medical attention. attention. subcutaneous emphyse emphysema ma occurs when A subcutaneous when air air from a ruptured ruptured lung collects under the skin, usual usually ly of the neck. This condition condition can cause cause swelling swelling in the neck, a crackl crackling ing sound sound when the skin is probed, probed, voice changes, changes, and difficult difficulty y in swallowing. swallowing. It also requires requires immediate immediate medical attention. attention.
H y p e r b a r ici c T r e a t m e n t If you do do suffer suffer an arterial arterial gas embolism embolism,, you will will needto be treated in a recompression chamber or hyperbaric hyperbaric chamber cham ber as as soon as possible. The chamber is pressurized to reduce reduce bubble size and restore blood cir cir culation culation.. Then, the pressure in the chamber chamber is released released slowly, allow allowing ing the gas to move from your your bloodstream and out of your body with each of your exha exhalations. lations. If you have any signs or symptoms of an air air embolism, you mus mustt seek seek medical medical attention attention at an opera tional tional chamber immediately. immediately. You should never go back under water to try try to relieve relieve the symptoms. symptoms.
Breathing and Circulation Transporting Transporting oxygen oxygen through your body is a vita vitall function function of of the circul circulato atory ry system, system, and proper proper gas exchang exchange e in the lungs lungs is critic critical. al. Each breath begins begins when your diaphragm, moves and your chest muscles pull pull your ribs out. These motions expand expand your chest chest and draw draw air air into into your lungs. Breathing in cause causes s the the alveoli to fill ill with fresh air. Oxygen ygen is absorbed absorbed through the walls walls of the alveoli alveoli and then through through the the walls of your capilla capillaries ries into your bloodstream. This This oxygen-rich blood is pumped by the heart through through your arteries arteries to your tissues. Your bodymetabolizes (uses) (uses) the oxygen and con verts it to carbon dioxide and other waste waste products. Your circul circulato atory ry system moves the carbon dioxide through your your veins and back to your your lungs, where it it passes through thewalls walls of the alveoli alveoli and out into the air when you exhale. exhale. Then the cycle starts starts again (figure (figure 4-29). At rest, most people people exchange exchange a few pints of air with each breath. When you are active, your breathing rate
Gas exchange in lungs Circulation in body tissues
blood from tissues
F IGI G U R E 4 - 2 9 . Y O U R B L O O D S T R E A M C I R C U LA LA T E S O X Y G E N T O Y O U R TISSUES AND REMOVES CARBON 0I0XIDE.
increases. This is your body’s response to the increased production of C02create C02created d by by activity. The harder you exercise, the more air you breathe. Because the the cyli cylin n ders ders you you use use for diving hold o only nly a finite amount of air, you can can see how exertion uses uses up your air air supply faster than when you are are relaxed.
H o w C a r b o n D io x id e C o n t ro l s Y o u r B r e a th i n g Actually, Actually, your breathing rrate ate is not controlled by the amount of oxygen, but by the amount amount of carbon dioxide, in your your bloodstream. bloodstream. Based on input from chemical chemical recept receptors ors in parts of your body body,, your brain brain sens senses es the the carbon dioxide level in your your blood and then increases or decre decreases ases the muscular muscular activity activity that controls breathing. breathing. The more carbon dioxide you have in your blood, the more you want want to breathe.
H o w l o B r e a tht h e D r i e r W a t e r Because pressure pressure and density are different under water than on land, you must modify your breathing breathing to accom modate these differences. Generally, Generally, for maximum effi effi ciency, your breathing should beslightly slightly slower than nor mal and deeperthan you usual usually ly breathe (figur (figure e 4-30).
I S
Chapter 4- Diving Science
pass out from a lack lack of of oxygen before you ever feel the need to breathe. This is called called shallow shallow water blackout. Moderate Moderate hypervent hyperventilati ilation on can extend extend your breathbreathholding time without a high level of risk, but only if you take a few few breaths. You should only take a maximum maximum of three or four four deep breaths before any breath-hold breath-hold dive.
Skip Breathing Skip breathing is is a dangerous technique some
F IGI G U R E 4 -3- 3 0 . Y O U R B R E A T H INI N G S H O U L O B E S L O W E R T H A N N O R M A L A N D O E E P E R T H A N Y O U U S U A L L Y B R E A TH TH E .
Shallow Breathing One mistake that that divers make is to breathe too shal shal lowly. If you breathe breathe too shallowly, shallowly, you do do not exchange xchange enoug enough h air air with each breath. breath. Only a small amount of carbon dioxide is eliminated eliminated when you breathe out. If you have too too much carbon dioxide in your your lungs, your your body will ill not allow allow much carbon di dioxide oxide to pass out of your bloodstream bloodstream and into your lungs. The increased level of carbon carbon dioxide dioxide in your blood will stimulate your desire to breathe. breathe. This need need to to breathe will ill get get worse worse if you continue continue breathing breathing shallowly. You will feel as if you you cannot get enoug enough air. air. The simple solution solution to this prob prob lem is sto stop p your activity activity and concentrate on breathing breathing slowly and deeply. deeply. Be especially especially sure toexhale fully with each breathing cycle.
Hyperventilation You can also get into trouble if if you deliberately deliberately breathe deeply deeply and rapidly. rapidly. This type of breathing is called hyperventilation and has the effect of lowering your body’s body’s carbon dioxide level. Deliberate hyperven hyperventiti(T ^ | lation can be be haza hazardo rdous us whe when n you follow it with a L L y brea breath th-h -hol old d skin skin dive dive.. If you hold your breath after excessive hyperventila hyperventila tion, your your bodywill ill continue continue using using oxygen oxygen, but your carbon dioxide level wil willl not reach the point where where your brain brain sens senses it is time to breathe. breathe. Therefore, you can
divers use because, incorrectly incorrectly,, they think it it will will extend the amount amount of time their cylinder cylinder of air will will last under under water. When a diver skip b breath reathes, es, they hold each breath for an extended extendedperiod of time rat rather her than than breathing breathing normally. Underwater Underwater photo photograp graphers hers will skip breathe breathe to minimize minimize the interference of bubbles. bubbles. You have already already read about the extreme extreme danger of lung lung overex pansion injuries injuries if if you hold your breath (Lung Overexpansi Overexpansion on Injuries, page 112). 112). The addition additional al danger in skip breathing is the buildup of carbon diox ide in the body body. If the carbon dioxide builds up, the diver is unable to breathe breathe enough enough air air for comfort in any situatio situation n that call calls s for them to exert them themselves under under water. They feel as if they are suffocating. suffocating. Divers who skip breathe can also develop develop painfu painfull headaches.
El
A i r S t a r v a t i o n You should also avoid avoid overexertion under water. Regulators have have a lim limit it as to howmuch air air they can give you. you. Basically, Basically, you are breathing through a restriction like a straw. straw. Should you try to work hard underwater, the car bon dioxide level will will build up in your body, even if you are breathing breathing deeply because of the added effort of breath breath ing through a restriction. When this happen happens, you feel starved starved for air, and you you feel that your regulator is not sup plying plying you with the amount of air you need. If you do do not take take prompt action to resolve the situation, you will will begin to have have feelin feelings gs of anxiety anxiety andposs possib ibly ly panic. panic. The The action action [ y l to take is to stop what you are doing, rest, and breathe slowly and deeply unti untill you recover, being sure to exhale fully fully with with each breath. breath. By taking taking it easy easy under water and learning learning your limits limits of exertion at various various depth depths, s, you can avoid avoid
NAUI Scuba Diver
overexertion. overexertion. You must must learn to breathe slowly and deeply whenever whenever you use scuba gear.
W tia t H a p p e n s W h e n Y o u In b a l e W a t e r Any time you are in the water, whether you are free diving, on scuba, or swimming, the possibility possibility exists exists that you will will get a mouthful of water when you least ex expec pectt it. This This commonly happens to swimmers, and some times happens to divers. Even a few drops of water can cause you to cough or choke. Keep your regulator regulator in in your mouth and choke or cough cough right through the mouthpiece. mouthpiece. You can also sneeze through your your regulator regulator.. You can almost almost eliminate eliminate choking as a problem problem if you always always inhale inhale cautiously cautiously when when taking your first breath after after clearing your regulator or snorke snorkel. l. If you do inhale inhale a little little water, cough and swallow repeatedly. repeatedly. Do not ascend ascend when coughing or choking. Coughing and choking or your respo response nse to it can can close your airw airway ay and ascending could cause a lung overexpansion injury. injury.
V e r i l y W h a t Y o u H a v e L e a r n e d Review the followi following ng questions questions about your lungs and breathing: 24. Lung expansion injuri injuries es are caused caused by or 25. Lung Lung volume volume should should be kept as as ________________________
INDIRECT EFFECTS OF PRESSURE The primary primary effects of pressure are physical changes that are easy tosee and experience. Other, more subtle, effectsfrom from pressure are just just as important important to your safety under water. These indirect effec effects of pressure impact impact divers by means of the gases in the air air we breathewhile while diving. diving.
Ingassing and Ottgassing When you breathe breathe in and out, the air you breathe is 78% nitrogen. Nitrogen is a metabolically metabolically inert gas, which which means that your your body does not use it. However, nitrogen nitrogen is absorbed and dissolved in your bloodstream and tissues. The pressure of nitrogen nitrogen is balanced balanced between the air and your body. ody. This state is called equilibrium. Under increased pressure, the air air you breathe is pressure of nitrogen you denser and the partial pressure you inhale inhale with each each breath is increased. Therefore, the pressure pressure of nitrogen in the a air ir you are breathing is greater greater than the pressure of nitrogen in your body. body. Your body body ingasses nitrogen until until the partial partial pressure pressure of nitrogen nitrogen in the air air you breathe is equal to the pressure pressure of nitro nitro gen gen in your body body.. When you ascend, the pressure decreases, decreases, and the parti partial al pressure pressure of nitrogen decreases. ases. Now the pressure ssure of nitrogen in your body body is greater than the parti partial al pres sure of nitrogen in in the air air you are breathing. To com com pensate, your bodyoffgasses nitrogen until until the nitrogen is balanced balanced between the air air and your body. body.
as possible dur dur
ing your ascent from a dive. 26. The stimulus to breathe breathe is the amount of in your blood. 27. When you are breathin breathing g on scuba, you should breathe and _____________________
_______________________
28. If I f you should choke, cough, or or sneeze while div ing, you should
D e c o m p r e s sis i o n S ici c k n e s s (DCS)) A problem problem called decompression sickness (DCS can occur occur if if you absorb absorb a great deal of nitrogen and then ascend ascend too quickly. quickly. It takes time for nitrogen to enter your body and it takes time for the nitrogen to leave your your body. When you ascend your body begins to eliminate eliminate nitrogen. If too too much much is still still present present after you surface, surface, the excess excess nitrogen nitrogen forms bubbles in your your body (figur (figure e 4-31 4-31). ). There are different different types of DCS. Each type has its its own symptoms. When bubbles bubbles form in your blood, they they can create microscopic microscopic clots clots that impair your circulation circulation.. When a
Chapter 4- Diving Science
c \
.Vein
i r Nitrogen Nitrogen bubble blockage in capillaries
/
F IGI G U R E 4 3 1 . A P R O B L E M C A L L ED E D D E C O M P R E S S I O N S ICI C K N E S S (DCS) CAN OCCUR IF YOU ABSORB A GREAT DEAL OF N I T R O G E N A N D T H E N A S C E N D T O O Q U ICI C K LYL Y .
bubble bubble forms in your tissues, your your body reacts to the bubble as if it were a foreign body. Symptoms of DCS can range from a skin rash, extreme extreme fatigue, coughing, and painfu painfull joints joints to paralysis paralysis and and unconsciousness. consciousness. You can and must prevent DCS when you dive. During your NAUI NAUI Scuba Diver certificatio certification n course, course, you will ill learn learn to use use the NAUI Dive Tables. Tables. These tables give give you time limits for your diving dep depth ths. s. Staying within the time limits limits is is the first step in preventing preventing DCS. The second step to preventing DCS is to always always ascend at a rate no faster than than 9 meters (30 feet) feet) per minute minute when you are using the NAUI Dive Tables to plan plan your your dives. This gives your body a chance to offgas some slight slight amount of nitroge nitrogen n as you ascend and to avoid the rapid pressure change that could cause bubble bubble forma forma tion. tion. The third step to preventing preventing DCS is to always per form a precau precautio tionar nary y decompression stop at 4.5 meters (15 feet) for 3 to 5 5minutes. minutes. You can also use a dive computer instead of the NAUI Dive Tables to help avoid avoid DCS. Remember that there is always a slight slight risk that you can suffer DCS even if you follow follow your NAUI Dive Tables or use your dive computer computer correctly. correctly. If you do suffer DCS, you wil willl need to be treated in a recompression chamber or or hyperbaric chamber as soon as possible (figu (figure re 4-32). The chamber is pressurized to cause the nitroge nitrogen n bubbles to go back into solution. Then, the pressure pressure in the chamber is released slowly, slowly, so the nitrogen nitrogen can can move from your tissues to your bloodstrea bloodstream, m, and out with each of
F IGI G U R E 4 3 2 . I F Y O U D O S U F F E R D C S , Y O U W I LLL L N E E D T O B E TREATED IN A HYPERBARIC CHAMB ER LIKE THIS ONE.
your exhalations. If you have any signs or symptoms of DCS, you must seek medical attention immediately. You should should never never goback under under water to try to relieve relieve the symptoms.
Nitrogen Narcosis Nitrogen under pressure can also produce an effect on your body called nitrogen narcosis or or “rapture of the deep" (figu (figure re 4-33)- At depths approachi approaching ng 24 meters meters (80 feet), feet), nitrogen nitrogen can be intoxicating. The narcoti narcotic c effect of nitrogen produces produces impaired thought and judgmen judgment, t, and it reduce reduces a diver’s diver’s physical ability. ability. The danger exists exists that a diver diver would be unable unable to func func tion well well enough to ensure their their safety. safety. The effects effects vary by individual individual and by day. day. The prevention to this problem is simple: avoid deep dives. The symptoms of nitroge nitrogen n narcosis narcosis increase increase in intensi intensity ty with depth. depth. Recovery is as simple as ascend ascend ing to a shallow shallower er depth depth where nitrogen has no effect. effect. The symptoms leave as rapidly rapidly as they occur and there are no after after effects.
E l
Oxygen Toxicity Oxygen is essential to sustain life, life, but breathing pure oxygen at depths below about 7.5 meters (25 feet) can be deadly. Oxygen becomes toxic at about tha thatt depth depth and, depending depending on individ individual ual sensitivi sensitivity, ty, can cause convulsions convulsions that can lead to drowning. Scuba
m
NAU I Scuba Sc uba D i ver
: e c n e i c S g n i v i D
Note: Note: All symptom s vary with different people and occur differently differently at va rying depths on each side.
Surface
50 ft.
Inability to to think clearly and make accurate judgements in some divers.
Dizziness in some divers. I-*-
100 ft.
150 ft.
Inability to communicate or perform simple motor or mental tasks.
200 ft.
Average Ave rage diver div er is more m ore or less useless and becomes a safety menace.
250 ft.
F IGI G U R E 4 3 3 . T H E S Y M P T O M S O F N I T R O G E N N A R C O S I S C A N B E S IM I M I LAL A R T O A LC L C O H O L INI N T O X I C A T I O N .
tanks must must never never be be filled filled with pure oxygen. The per centag centage e of oxyge xygen n in regular air air is not toxic until until well well below to the sport-diving lilim mit of 40 meters (130 feet). feet). Some divers receive specialized trai trainin ning g in the use use of special gas mixtures that that have a percentage of oxygen and nitrogen different from the percentages in regular regular air. These These mixtures are referred to to as nitrox nitrox or enriched air air (figure (figure 4-34). 4-34). Nitrox has other benefits, but but becau because it has a higher higher percentage of oxygen oxygen than air, air, maxi maxi mum dive depths are actu actual ally ly reduced. Using these gases requires requires special train training ing.. Ask your instructor instructor about the NAUI NAUI Enrich Enriched ed Air Nitrox specialty specialty courses courses in your area if if you are intere interested sted in learning learning about about diving with with these gases.
118
C a r b o n M o n o x i d e T o x ici c iti t y Carbon monoxide iis s a gas formed by the incom plete combustion usually usually of a petroleum product such as gasoline or oil. This gas is potent potentiall ially y dangero dangerous us even in small concentrations, especially when it is breathed breathed under pressure. ressure. Carbon monoxide monoxide itself is colorless, odorless, and tasteless tasteless but air air that has been been contaminat contaminat edwith it might taste taste and smell smell oily oily or foul. Divers can encounter problems with carbon carbon monox ide if if exhaust fumes from a gasolinegasoline- or diesel-powered engine contaminate contaminate their their air air supply. supply. This occurs when when the intake intake for for the compressor is placed placed too close to the exhaust for any engine, in inclu cludin ding g the engine that drives the compresso mpressor. r. In this situati situation, on, gases ses from the the engine engine exhaust are compressed pressed along with the air. air. In addition,
Chapter 4- Diving Science
If the air air in in your tank tank has an odor odor or taste, do do not not use it. Notify the faci facilility ty that fille filled d the tank as soon soon as possible so they can investigate investigate the problem. You can avoid carbon mono monoxide xide poisoning by always having your your tanks tanks filled filled at a professional professional dive facilit facility y where where the com com m pressor pressor is properly set set up and maintai maintained ned (figur (figure e 4-35). People People who smoke expose themselves to increased increased levels of carbon monoxide. This is another reason divers should should not smoke.
i v i n g S c i e n c e
V e r i t y W h a t Y o u H a v e L e a r n e d
I F IGI G U R E 4 - 3 4 . N I T R O X ISI S A N A C C E P T A B L E G A S T O U S E F U R O I V ININ G I F Y O U H A V E B E E N T R A I N E D T O U S E I T.T .
Review the followi following ng questions questions about the indirect indirect effects of pressure: 29. How can you prevent oxygen toxicit toxicity? y? 30. How can you prevent carbon monoxide toxicity? toxicity? 31. How can can you prevent DCS DCS??
32. How can you prevent nitrogen narcosis? 33- If If your your buddy has has symptoms of nitrog nitrogen en narcosis, what should you do?
F IGI G U R E 4 3 5 . A L W A Y S H A V E Y D U R T A N K S F I L L E D A T A P R O F E S S I O N A L D I V ININ G C E N T E R O R S T O R E .
a compres compressor sor that has been lubricated lubricated with with the wrong wrong oil oil or that overheats overheats can produce produce carbon monoxide. Truck or automobile exhaust fumes fumes are another another poten tia tial source of carbon carbon monoxide. Keep the compressor intake as high and as far far away from potential potential carbon carbon monoxide sources as possible. possible. Once Once carbon monoxide monoxide is inhaled, inhaled, it interferes with the blood’s ability to carry oxygen to the tissues. Symptoms of carbon monox monoxide ide poisoning include include nau nau sea, blue lips lips and nail nail beds, confusion, headache, and unconsciousness. Fresh air air is helpful, helpful, but pure pure oxygen and immediate medical attention are needed needed for proper treatment.
T H E R M A L E F FE F E C T S O F D IV I V IN IN G When the water temperature is colder than than your skin temperature, temperature, you should wear some type type of insulation insulation while while diving. You lose heat under under water in several ways: • The water condu conducts cts heat away from your body rapidly. • Each time you take a breath under water, you breathe in cool, compresse pressed d air air that you must warm to your body temperature. • Each Each time you exhale under under water, you lose lose the heat energy you used used to warm the air air you inhaled.
119
NAUI Scuba Diver
Humidity and Temperature
G O
Humidity is the amount of water vapor in the air. The higher the temperature temperature of the air air,, the more more water vapor it can hold. hold. If the air containing containing the water vapor is cooled, the water water vapor in the the air air condenses. When you enter the water and and descend, the air air inside your mask cools. This causes the the water vapor in the air air to condense, which fogs the lenses in your your mask (figure (figure 4-36). This is known known ascondensation. When water condenses on the lens of a mask, it it forms bead beads s of water. If you use a defogging solution surface tens tension ion of you reduce the surface of the water in the mask. When the surface surface tension is reduced, reduced, any mois ture that does conden condense spreads out in a thin thin film film instead of forming drops that can block your vision. vision. The air inside your scuba cylinde cylinderr also warms warms and cools. In extremely cold water, water, condensation can cause cause scuba regulators regulators to freeze and freeflow freeflow unless a coldwater diver takes takes special precautions with their regulator. Normally, the air in scuba cylinders has has had almost all all of of the water removed from it as the air is compressed into the cylinder. cylinder. This This is necessary to keep moisture out of your cylinder cylinder to prevent corrosion. Because the the air you are breathing breathing is is so dry, dry, your your body must heat and humidify humidify it as you breathe in. Having to humidify humidify the air causes dehydration, which which is the loss of body body fluids.
Increased pressure '">m heal
F IGI G U R E 4 3 7 . W H E N T H E T EM E M P E R A T U R E O F A S C U B A C Y L INI N O E R R I S E S , T H E G A S M O L E C U L E S I N S I D E T H E C Y L INI N D E R A L S O B E C O M E M O R E A C T I V E . T H I S C A U S E S T H E P R E S S U R E I N S IDI D E T H E C Y L INI N D E R T O R I S E .
You must drink drink plenty of fluids fluids before, between between,, and after dives dives to replace the lost fluids. Dehydration decre decrease ases your abil ability ity to exercise ercise at full full capacity and makes you more susceptible susceptible to decompression sickness. Anything Anything you drink before diving diving must be non-alco non-alco holic and should not contain caffeine. Caffeine is a diuretic, which means it will cause you to urinate and lose lose additional additional fluids. You should should drink decaffeina decaffeinated ted coffee, caffeine-free soft or sport sport drinks, decaffeinated tea, juices, juices, and and water.
Scuba Cylinders and Temperature
F IGI G U R E 4 3 6 . Y O U R M A S K F O G S W H E N T H E W A T E R V A P O R I N T H E A I R I N Y O U R M A S K C O N D E N S E S .
When a container container fill filled ed with with a gas is heated heated, the gas molecules inside the container becom become more active. If the container is flexible, the container will expa expand nd.. If the container is not flexible (for (for example, example, a scuba scuba cylinder), cylinder), the pressure ressure inside the the container container will will rise (figur (figure e 4-37). Cylinders should be kept from extreme extreme heat after after they are filled. filled. If the cylinder cylinder is subjected subjected to changes changes in temperature temperature once it is full full,, the pressure pressure inside can vary by several bar (several hundred psi). psi). The pressure pressure will ill increase or decrease decrease by approximately approximately 0.6 bar for each change of 1°C 1°C (5 psi psi for each change of 1°F 1°F)) even though no air air has been added or lost. This change occurs beca because use the the molecules of air air speed or slow their activit activity y as the temperature rises or
Chapter 4- Diving Science
falls, falls, respectively. Because of this change, it is not a good idea to store store scuba cylinders in car trunks, which which can reach reach temp temperatu eratures of over 50°C (122 (122°F °F). ). There is littl little e danger from the pressure pressure increase becaus because e of heat, but if a cylinder becom becomes hot enough, it will rupture the burst disk in the valve. valve. Also, Also, if the cylinder cylinder repeatedly expands and contracts ffrom rom the changes iin n temperature, it wil willl stress the metal and shorten the useful life life of the scuba cylinder. cylinder. It is better better to store cylinders cylinders with only only 7 to 14 14 bar (100 to 200psi) psi) of air air and fil filll them just before use than to store store them full. full. The metal metal alloys from which aluminum aluminum cylinders are made will crystallize if subjecte subjected d to relatively relatively low heat. They should not be placed near fires. If smoke smoke stains are are found found during the annual visual visual cylinder inspection, the cylinde cylinderr cannot be approved proved for use.
V e r i f y W h a t Y o u H a v e L e a p n e d Review the followin following g questions questions about the thermal thermal effects of diving: diving: 34. You lose lose most heat under water prim primar arily ily from water and some from warming . 35. Water vapor in air air condenses enses to a liquid liquid when ____________________________
___________________
36. You can prevent a mask from fogging under water by by lowering the the of the water. 37. You must drink plenty of fluids when diving to __________________
38. True or or False. If the temperatur temperature e surrounding a rigid rigid container container fu full of gas increases, the pressure ressure of the gas increases.
i v i n g S c i e n c e
NAUI Scuba D i ver
LEARNING GOALS In this chapter chapter you you will: • Learn about ingassing ingassing and offgassing nitrogen and how it affects the amount of time you can spend underwater. underwater. • Understand Understand the conce concept pt of residual nitrogen. • Learn about dive table terms and rules. • Learn how to use the NAUI Dive Tables to plan your dives and find your your Letter Group designation after each dive. • Be introduced tothe NAUI Dive Pla Plann nnin ing g Worksheet and howto use it to keep track of the inf informat ormation ion from your dives and the NAUI Dive Tables. • Leam about precautionary and mandato mandatory ry decompression stops and how import important ant they are in minimiz minimizing ing the risk risk of decompression ression sickness sickness.. • Be introduced to the NAUI Dive Time Ca Calcul lculato atorr and how to use it. • Be introduced to dive computers computers and their their benefits. Your depth, and tthe he number and depth of dives dives you have made made in a series are two major major factors that determine the length of time you can stay under water. water. This This chapter explains the use use of the NAUI Dive Tables, the NAUI Dive Dive Time Calcula Calculator tor,, and dive computers. computers. You plan your dives with with the correct time and depth depth lim lim its by using either either version of the NAUI Dive Tables or a dive computer.
N I T R O G E N A N D D IVI V IN IN G The gase gases s in the air air you breathe disso dissolve lve into into your body’s body’s tissues tissues according to the part partia iall pressure of each gas in the air. air. Air is 78% nitrogen, 20.9% oxygen, oxygen, and 1.1% other gases. Your Your bodyuses part part of the oxygen you inhale inhale with with each breath. Your tissues tissues use the oxygen oxygen for the chemical chemical processes that keep keep you alive, alive, convert converting ing it to carbon carbon dioxide and other waste products. However, the nitrogen that that dissolves dissolves in your tissue tissues during your dive is is the gas you must be concerned concerned about when you plan your dives.
124
ingassing Nitrogen When you breathe in and out, out, the air air you breathe is 78% nitrogen. nitrogen. Nitrogen is a metabolically metabolically inert gas, gas, which means that your your bodydoes not use it. However, nitrogen nitrogen does absorb into into your your bloodstream bloodstream and tissues tissues as oxygen does. The pressure of nitrogen nitrogen is balanced balanced between the air air and your body. This state is called equilibrium. par tial pressure of Under increased increased pressure, pressure, the partial of nitrogen you inhale with each breath is increased. Therefore, the pressure pressure of nitrogen nitrogen in the air air you are breathing is greater than the pres pressur sure e of nitrogen in in your body. body. Your body body ingasses nitrogen until the pres sure of nitrogen in your your body body equals the pressure pressure of nitrogen in in the air air you breathe breathe.. If the new pressure ressure is constant, ingassing occurs rapidly rapidly at first and then slows unti untill your body reaches reaches equili equilibriu brium m many hours later. later. You do not experience experience any negative negative effects when ingassing occurs at moderate depths. The different different tissues of your body (fat, (fat, muscle, bone, bone, and so on) absorb absorb nitrogen at different different rates when you are under water. Your muscle absorbs nitrogen quickly, quickly, but fat absorbs nitrogen slowly. There are differ differ ent ingassing rates for each type of tissue. tissue. Calculat Calculating ing the cumulative cumulative effects effects of the ingassing rates for each type of tissue requires complex mathematics. mathematics. Dive tables, dive computers, computers, and dive time calculat calculators ors consid er all all these these varying rates and and eliminate eliminate the need need for you to make complex calculations.
Offgassing Nitrogen After you you spend spend time under water, the increased par tial tial pressure of nitrogen nitrogen has caused your body body to absorb a quantity quantity of nitrogen from the air air you breathe on on scuba. This quant quantity ity has been added added to the quantity quantity found in your your body body at sea level. level. When you ascend, ascend, and the ambient ambient pressure pressure decreas decreases, es, the part partia iall pressure of nitrogen nitrogen decreas decreases. The pressure pressure of nitrogen in your your body is now greater than than the partia partiall pressure of nitrogen in the air you are breathing. Your bodywill offgas offgas nitro nitro gen unti untill the nitrogen nitrogen is balanced balanced between your body body and the air.
Chap ter 5-5- Decom pression, pression, D ive Tables, and Dive Com puters puters
F IGI G U R E 5 - 1 . T H ISI S B O T T L E O F S O D A W A S S E A L E D U N D E R P R E S S U R E . W H E N T H E B O T T L E ISIS O P E N E D , B U B B L E S FORM B ECAUSE OF THE SUDDEN DROP IN PRESSURE INSIDE THE BOTTLE.
The excess nitrogen nitrogen passes from your your body tissues into your blood. blood. The nitrogen then passe passes from your blood to your lungs, where you exhale the nitrogen. This process occurs rapidly rapidly during during the first few minutes after your ascent, but it takes takes many hours for your body’s nitrogen level to return to normal. If you reduce the pr pressu essure re on your body gradually, gradually, and the reduction in pressure from the depth of your dive to the the surface is not too rapid for the amount of nitrogen you have absorb absorbed, ed, offgassing occurs without without a problem. However, if the change in pressure is sudden, r y j the the nitrog nitrogen en in your tiss tissues ues can com come out of solution solution so so rapidly rapidly that that bubble bubbles s form in your your body. These These bubbles can damage tissues and cause a painf painful ul condition condition known as decompression sickness (DCS) or classically, as the bends. A bottle of soda can illu illustr strate ate the princ principl iple e of DCS. Carbon dioxide is dissolved dissolved in the soda under pressure and it remains in solution solution until until opening opening the the bottle bottle reduces the pressure. The rapid rapid drop in pressure causes the carbon dioxide to form bubbles bubbles in the liq liquid uid and the
soda foams (figure (figure 5-1). 5-1). If you open the bottle bottle slowly, reduced bubbling occurs. You must control control the two factors that that affect affect in-and offgassing: time and pressure. pressure. You do this by control control ling ling your dive time and depth. depth. To do this, you rely on the informatio information n provided by dive tables, dive time calculat calculators, ors, and dive compute computers. rs. You must also consider factors that can can increase increase your chance of suffering DCS DCS in situations where where it might not normal normally ly occur. These factors include dehydration, dehydration, fatigue, injuries, injuries, hard work during or shortly after a dive, effects effects of of drugs or alcohol, alcohol, obesity, or advanced advanced age. In any case, you mustbe fit fit for diving diving and dive conservatively. Bubbles form in the human body if pressure pressure is reduced beyond a specific point. point. If you dive deeper deeper than approximately approximately 6 meters meters (20 feet) and then ascend, the pressure pressure change might might be sufficient sufficient for for bubbles to form if you have absorbed absorbedenough nitrogen. If you dive to to depths of 6meters meters (20 feet) feet) or less, DCS is not lilike kely ly to occur unless you go to to altitude after diving, which reduces the pressure outside your your body and can create create a sufficient pressu pressure re differentia differentiall to cause cause bubbling. For For depths of 6.4 meters (21 feet) feet) or deeper, time time limits called dive time limits or or no-decompression limits have been established. established. The time spent at a given depth is not to exceed ceed these these limits, limits, or you could could experi ence DCS during during or after your ascent from the dive. If you take take special precaution precautions, s, involv involving ing offgassing offgassing in a series of planned planned decompression stops during during ascent; you lesse lessen your risk of of DCS. DCS. The United States Navy has established time limits limits for for various various depths based on research and field field experience experience of milita military ry divers. divers. Recreational Recreational diving diving use uses shorter time time limits than those those in the US Navy ta tables bles (fig (fig ure 5-2). Research and analy analysis sis by many experts experts deter mined that shorter dive time limits limits would would reduce the the risk of DCS DCS during recreational recreational diving. Reduced Reduced time limits limits have have been incorporated incorporated into the NAUI Dive Tables and NAUI Dive Time Calculato Calculator. r. Most Most dive computers also use use shorter time limits limits than than the US Navy tables for a single dive at a constant constant depth. Any dive you make puts you at at risk risk for DCS. However, diving with within in the limi limits ts set by the dive tables
e c o m p r e s s i o n , D i v e T a b l e s , a n d D i v e C o m p u t e r s
NAU I Scuba D i ver
DIVE LIMITS
r e t u p m o C e v i D d n a , s e l b a T e v i D , n o i s s e r p m o c e D
i
D E P TH
N A U I L I M IT
U.S.N. LIMIT
0-20’ (0-6m)
No Limit
No Limit
21-40’ (6.4-12m)
130 mi ns.
200 mins.
41-50’ (12.5-15m)
80 mi ns.
100 mi ns.
51-60' (15.5-18m)
55 mins.
60 mins.
61-70’ (18.6-21 m)
45 mi ns.
50 mins.
71-80’ (21,6-24m)
35 mi ns.
40 mi ns.
81-90'(25-27m)
25 mins.
30 mins.
91-100'(27.6-30m)
22 mi ns.
25 mi ns.
F IGI G U R E 5 - 2 . R E C R E A T I O N A L D I V ININ G U S E S S H O R T E R D I V E T I M E L IM IM I T S T H A N T H E U S N A V Y T A B L E S . ] Represents Residual Residual Nitrogen Nitrogen
lessens the risk. Divers who use time limi limits ts in in excess of the recommended mended limits limits (for (for example, example, technic technical al divers) divers) recognize recognize and accept the increased risk that that is associated with these longer dive times and the need for special special decompression procedures. Deepe Deeperr diving requires experience, plannin planning, g, and training. training. As a certified entry-le entry-level vel NAUI Scuba Diver, you should should not dive dive to depths deeper than than 18 meters (60 feet). feet). As a certified certified NAUI Advanced Advanced Scuba Diver, Diver, you should should not dive dive to depths deeper than than 30meters (100 feet). feet). The maximum recommended recommended depth for all recreationa recreationall divers is 40 meters meters (130 feet). feet). You do not need to memorize the dive time limi limits. ts. They are included in your NAUI Dive Tables Tables or your NAUI Dive Time Calculato Calculator. r. Note that the dive time decreases as the depth depth increases. If you are using using a dive computer, computer, the limits limits wil willl probably be different different from the the limits limits present presented ed in this textbo textbook. ok. Nitrogen offgassing occurs at different rates among your various body tissues. The rate of offgassingfor differ differ ent tissues is the basis for the non-linear variatio variation n in time limits for for different different depths. You should be fami familia liarr with this concept becau because it does form the basis basis for the calc calcul ula a tions performed by dive computers and the time limits limits established by dive tables and dive computers. computers. When you take the the NAUI Master Master Scuba Diver course, you wil willl leam various various principles principles and theories behind dive tables.
F I G U R E 5 -3- 3 . R E S I D U A L N I T R O G E N I S T H E N I T R O G E N T H A T S T A Y S I N Y O U R B O D Y F R O M D IVI V E S M A D E I N T H E P R E VIV I O U S 2 4 H O U R S .
residual nitrogen. nitrogen. In reality, reality, it takes takes hours to fully fully absorb nitrogen into your body or fully eliminate nitro gen from your body body.. If you dive and absorb nitrogen at depth, ascend to the surface, surface, and then make make another another dive within within 24 hours of the first dive, you will will stil stilll have nitrogen in your body body from the first dive (figure (figure 5-3). 3). Your bodywill ill absorb nitrogen from from the second dive in addition to the nitrogen nitrogen remaining remaining from the first dive. dive. You must must always take the nitrogen remaining remaining in in your your sys tem from any previous series of dives into account when planning planning your next dive. dive. This residual nitrogen redu reduces your time time limits limits for any given depth depth on your next dive.
V e n ify if y W lis li s t Y o u Have Learned Review the following following questions about ingassing ingassing and outgassing nitrogen: 1. When you go under pressure, y your our body nitrogen until it reaches a state state of of . 2. Bubbles form during during offgassing when when you _________________
_________________________ _________________________
3. You can dive to meters meters ( without a dive time limit. 4. Residual nitrogen is the nitrogen
_______
Residual Nitrogen To properly use dive tables, dive time calculators calculators,, and dive computers, you must understand the concept concept of
126
feet)
m
Chap ter 5 17431727 " :
DIVE TABLE OVERVIEW The NAUI Dive Tables use use a Letter Group designation designation to express the amount of residual residual nitrogen nitrogen in in your your body. The letters range in sequence from Ato L. The letter letter A represents a small small amount amount of nitrogen and the amount of nitrogen increases as the letters progre progress towards L. When you dive, a Letter Group from the tables designates the the amount of nitrogen you have absorbed during during the dive. As you spend time on the surfa surface ce between dives, you are assigned to “lower” “lower” Letter Groups Groups as you offgas nitrogen. When you you start a dive ag again ain to a given depth, depth, your Letter Group at tha thatt time determines the time represent ing the residual nitrogen in your body. The tables show show you how to subtract this time from the normal normal dive time limits, which results in a shorter shorter time limit limit for your repetitive dive. You must add your residual ni nitrogen trogen time to the the time you actua actually lly spent diving to determine your total nitrogen time time at the end of the dive. You use the total time to determine a new end-of-dive Letter Group. The NAUI NAUI dive time calcu calculato latorr is based based on the NAUI dive tables, tables, but it eliminates the calculations calculations required to determi determine ne Letter Groups when you make more than one dive. The dive time calcu calcula lator tor also reduces the errors that that are are often made when readi reading ng dive tables. It is easy easy to learn learn how to use a dive time calcu calcula la tor, but you should should do this only after you you are fam familia iliarr with the the proced procedures ures for planning planning dive time limits limits using the dive tables. tables. A dive time calcula calculator tor might might not always be available, but dive dive tables tables usually are (figure (figure 5-4). 4).
, Dive Tables, Tabl es, aad D ive Com puters puter s
A variety of dive dive tables, dive time calculators, calculators, and dive computers exist. The informati information on they provide varies varies and some some are more conservative than than others. Numbers and Letter Groups Groups are not always intercha interchange nge able between tables. tables. Always use use the the type of table, calcu calcu lator, or comp compute uterr with with which you you are familiar. If your dive buddy is using a different different type, you should should agree to use use the most most conservativ conservative e dive planning planning infonnation. infonnation.
c o m p r e s s i o n ,
Dive Table Terms Different Different dive tables and dive computers computers might use use terms different different from the ones used in the NAUI Dive Tables (figur (figure e 5-5). Also, Also, the same same term might have a different meaning. The following following terms apply to the NAUI Dive Tables: Dive Sche Schedu dule le.. This is an abbreviated statement • Dive giving giving the depth and time of the dive. It is expressed as depth/time ((fo forr example, example, 21 meters/40 minutes or 70 feet/40 minute minutes) s).. It is also called a dive profile, especially especially when when it is one dive in in a sequence of dives. Dive Tim Timee (MDT). • Maximum Dive (MDT). This is the time you can spend at a given depth without havi having ng to do a required decompression stop during during ascent. This time is also also known as the Maximum Allo Allowa wabl blee Dive Dive Tim Timee or no-decompression limit. lim it. or no-decompression Decomp mpre ress ssio ion n Stop Stop.. This is a point in a dive • Deco dive where you stop stop at a specified depth for a specified
D i v e
m
T a b l e s , a n d D i v e C o m p u t e r s
No Decompression Limit
F I G U R E 5 -5- 5 . T H E D I V E T A B L E T E R M S F D R T H E N A U I D IVIV E T A B L E S M I G H T F IGI G U R E 5 - 4 . D I V E T A B L E S A R E U S E D T D P L A N Y O U R D I V E .
H A V E D I FFF F E R E N T M E A N I N G S W I T H O T H E R D I V E 1 A D L E S .
127
NAU I Scuba S cuba D i ver
m e t u p m o C e v i D d n a , s e l b a T e v i D , n o i s s e r p m o c e D
128
□
time during ascent to allow allow nitrogen offgassing before before continui continuing ng your ascent or surfacing. surfacing. Precautionar onaryy Deco Decomp mpre ress ssio ion n St Stop. - Precauti This is a stop stop at five meters meters (15 feet) for three minutes as a safety precaution precaution when you have not exceeded the Maximum Dive Dive Time. You should should perform such a stop at the end of every dive. It is also known known as as aSafety Stop. Required Deco Decomp mpre ress ssio ion n St Stop. - Required This is the amount of time specified by the NAUI NAUI Dive Tables, that that you must spend spend at five meters (15 feet) whenever you exceed the Maximum Dive Time. Time. Other tables specify additional additional stop depths for deeper or llonger onger dives. Actual Actual Dive Dive Time Time (AD (ADT). T). This is the elapsed 1 time from from the moment you begin your your descent from the surface surface unti untill the time you retur return n to the the surface. Time spent spent at your Safety Stop does does not need to be included in the Actual Dive Ti Time me when determining your Letter Group. Residual Nitro Nitroge gen. n. This is the excess nitrogen 1 Residual nitrogen remaining remaining in your your body from any dive or dives made before you have complet completely ely offgassed. offgassed. Letter er Grou Group p Des Desig ignat natio ion. n. This letter symbol * Lett symbol identifies identifies the amount of residual nitrogen you have in your syste system m. The closer the letter is to the beginning of the alphabet, the less residual nitrogen you have in your body. body. »Sur »Surfac facee Interv Interval al Time Time (S (SIT). IT). This is the time spent on the surface surface between dives. During During this this time, your body is elimi elimina natin ting g excess cess nitrogen. Your Letter Group will will change and move move closer to the beginning of the alphabet, depending depending on how long you are on the surface. »Rep »Repeti etiti tive ve Dive Dive.. This is any dive that you make before you have complet completely ely offgassed from any any previous dive dive or dives. »Residua »Residuall Nitrog Nitrogen en Time (RNT (RNT). ). This is the amount of time you must consider as already having having been been spent at a given depth depth for a planned planned repetitive dive. This time is based based on the residual nitrogen remaini remaining ng in your body from a previous dive or dives.
Adjusted ed Maximum Dive Dive Time Time (AMDT). This is • Adjust the Maximum Dive Time minus the Residual Nitrogen Time for for a repetitive repetitive dive to a given depth. • Total Nitrogen Time (TNT). This is the the sum of your Residual Nitrogen Time and your Actual Actual Dive Time followin following g a repetitive dive. dive. You use use this total total to obtain obtain your new Letter Group Group at the end of the dive.
Dive Table Rules You must understand understand the the following following NAUI Dive Table rules completely. Sim Similar ilar rules will will apply to any new new set of dive tables or di dive ve computer that you might might use to calculate calculate your dive times. • Ascend no faster than than 9 meters (30 feet) feet) per m minute minute.. This This is 0.3 meters (1 foo foot) t) every every two sec onds. You need a timing timing device device and a depth gauge (or (or a dive computer) to measure your rate of ascent. This rate rate will will seem quite slow to to y you. ou. • Use the exact or the next greater number listed listed in the table for your depth depth.. If you excee exceed d a number number in the table, use the next greater number. The depths in the table table range from from 12 meters (40 feet) feet) to 40 meters (130 feet) feet) and increase increase in increments of 3 meters meters (10 feet). For example, you round round a dive to 13meters (43 feet) feet) up to a 15 meter (50 foot) foot) dive. • Use the exact or the next greater number listed listed in the table for your time. If you exceed a number in the the table, use the next next greater number. number. The times range from 5 minutes minutes to 130 minutes. For example, you round a dive to 15 meters (50 feet) for for 41 minutes up to 50 minutes. • Use the deepest depth you reached duri during ng your your dive to determine the dive schedule for your dive. For For example, if you you do a dive to 18 meters (60 feet), feet), but spend most of the time a att 12 meters (40 feet) feet),, you must consider consider the dive to be an 18 meter (60 foot) dive. • Always make your deepe deepest st dive first first when making making a series series of dives. dives. Plan Plan each of your repetitive dives to a shallower depth than your your previous K dive. This might allow allow you to offgas nitrogen on
Chapter 5- Decompression, Dive Tables, and Dive Computers
□
m
□
progressively shallower dives and prevents prevents you from carrying carrying progressively progressively larger amount of residual nitrogen on deeper repetitive dives. dives. Consider any dive shallow shallower er than than 12 meters (40 feet) feet) to be a 12-meter (40-foot) dive when plan plan ning your dives. Surface Interval Interval Time (SIT (SIT)) must must be at least least 10 10 minutes betw between dives. dives. If your SIT SIT is less than 10 minutes, you must consider your second dive as a continuat continuation ion of the the first first dive. NAUI recommends mends a SIT SIT of at least one hour between dives. ives. 1Use the next next greater dive time if if your dive is par par ticular ticularly ly cold or strenu strenuous ous.. For example, if you do a dive to 18 meters (60 feet) feet) for 22 minutes, minutes, the 22 minutes minutes rounds to 25 minutes. minutes. However, if you become chille chilled d during during the dive, round the time again again to 30minutes. 1Avoid dives that take you right right to the no-decompres sion limi limitt for any given depth andtime combina tion. If you accidentally accidentally overstay overstayyour bottomtime or use an incorre incorrect ct ascent rate on such a dive, you could be in a required required decompression situation situation or suffer DCS. Always allow allow yourself enough time to make a slow, comfortable ascentwith plenty of air. air.
DIVE TABLE ORGANIZATION The NAUI Dive Dive Tables are composed of three tables: • Table 1- End-Of-D -Of-Dive ive Letter Letter Group Group • Table Table 2- Surface Surface Interval Time Time (SIT (SIT)) Table • Table 3- Repetitive Dive Dive Timetable The NAUI Dive Dive Tables are based on on the US Navy Decompression Tables and and have been designed specif specifii cally cally for recreational diving (figure (figure 5-6). The tables tables are designed designed to flow from one to the other in a continuous loop (figure (figure 5-7). When you are are using using the tables, be sure to use a ruler ruler or a straight-edg straight-edged ed object to read the numbers across across and work your way from table to table. table. If you try using a finger finger to trace your path through the tables, you might slide into another row and read the the table incor incor rectly, especially especially if if you are on a rocking boat.
p r e s s i o n , D i v e T a b l e s , a n d D i v e C o m p u t e r s
V e r i t y W i i a t Y o u H a v e L e a r n e d Review the followi following ng questions about Dive Dive Table Table Rules: 5. When you use the NAUI Dive Tables, you ascend from all dives dives at a maximum rate of meters (_ (_ feet) per minute. 6. You should allow a minimum of min min utes between dives and NAUI recommends a SIT SIT of . 7. Arrange the foll followi owing ng dives into the preferred sequence: 9 meters (30 feet)/40 minutes 18meters (60 feet)/30 minutes 15 meters (50 feet)/20 minutes 8. Adive of up to 8 meters (26 feet) feet) for 40minutes minutes should be considered considered as a dive schedule schedule of when planning a repetitive dive.
c o m
_______ _______
________________ ________________
___________________
F IGI G U R E 5 -6- 6 . T H E N A U I D I V E T A B L E S H A V E B E E N D E S I G N E D F O R R E C R E A T I O N A L D I V ININ G A N D A R E E A S Y T D U S E .
NAIII Serin Diver
TABLE 1 - END-OF-DIVE LETTER GROUP M
M
M
D IV E T A B L E S
00 I DIVE DIVE TIME TI ME REQUI RING DECOMP RESSIO N NO MINU TES REQUIRED AT 15‘ STO STOP P (5M)
SWBT
i tttt M W M S r o * s r P i £ ' C 0 M « ! A « 5 V Wl Wl t' l i : < s t r t f e f S W H i H O T S U M w n t f MO M !'J o f K W B t s w * s j cm cm k s s a t m . i m v
RN T RtS IDUAl NITROGEN TIME +A DT ACTUALDIVETIME ACTUALDIVETIME TN T TOTAL NITROSEN TIME IUSE THISfIGUfif TO , / OtTESMIN OtTESMINEE * / END-OfDIVE . U T T E R G RO RO UP UP ! / -
V
cam
WM »i. iwaitmswoHtHHij' i
‘ft'
12 40 V 15
50v
18
60 v
80:100 110 5 15 25 30 40:50 70 80:1
130a
i10 15 25 30 40 5060 70 80 10 15 20 25(30 40 50 55
n
21 70 v
5
10 15 20:30 35 40 45
24 80 V
5
27
90v
5
10 15 20 25 30 ( 35 n 10 12 15'2 0 ‘ 2 5 1 ^
30 100v
5
7
■ a *
10 15 2 0 (22
33 110v
5 10131 y 15y
36 120v
5
40 130 V
5
8a
C
D
A
B
yn io I? y
a
_. _.
A
E
F
irn
EX
H
I
J
K
L
.
TrZS
* 0-.10(W6 V16
?«
SO O<< J S H S a #
TifTTMe; WO’?-*
T oacjias -;(WT*0>«# IS*
AVOIO - REPETITIVE DIVES OVER 100 FEET TABLE 3 - REPETITIV E DIVE TIMFTABLE
A
B
C
D
E
F
G
H
I
J
K
L
F IGI G U R E 5 - 8 . T A B L E 1 - E N D - O F -D- D I V E L E T T E R G R O U P.P .
03S;0»»6
TABLE 2 - SURFACE INTERVAL TIME (SIT) TABLE
F IGI G U R E 5 - 7 . T H E N A U I D IVI V E T A B L E S A R E D E S I G N E D T O F LO LO W F R O M O N E T A B L E T O T H E N E X T I N A C O N T I N U O U S L O O P.P .
T a b l e 1 - E i f - D i v e L e ttt t e r O rer e o p Table 1- End-OfEnd-Of-Dive Dive Letter Group gives you a Letter Group designation at the end end of your dive (figure (figure 5-8). 5-8). This table table also gives you the Maximum Dive Time (MDT) (MDT) inform informati ation on for for depths from 12 meters to 40 meters (40 (40 feet to 130 feet). feet). The MDTs are the red, circled numbers. The table is arranged arranged with with the depths pths in columns columns on the left side of the table and and the times for eac each h depth in rows across across the table. To find your your Letter Group, use the follo following wing steps: 1. Take the deepest depth you reached reached duri during ng your your dive and round round it to the next greater depth found in Table Table 1. For example, example, if if the dee deepe pest part of your your dive was to 23 meters (75.5 feet), feet), round the number to 24 meters (80 feet). feet). 2. Locate the row corresponding corresponding to yo your ur deepest depth. 3. Follow Follow the row across until until you you find the column containing containing the total time of your dive. dive. You might have to round the total time of your dive to the next greater time found on the table. table. For
example, if if the total time for your dive to 23 meters (75.5 feet) feet) was 26 minutes, minutes, you must round the time time to 30 minutes. 4. Follow the column containing the total total time of of your dive down until until you reach a letter. This is your Letter Group Group designation for your dive. For example, the Letter Group for the dive dive to 23 meters (75.5 feet) for 2 6 minutes, which is round ed to 24meters (80 (80 feet) for for 30minutes, minutes, is G.
V e r i l y W h a t Y o u H a v e L e a r n e d Review the followin following g questions questions about Table 1: 9. If you do a dive to 18meters (60 feet) for 42 minutes, your Letter Group is ____ . 10. If If you do a dive to 12 meters (40 feet) feet) for 88 minutes, minutes, your Letter Group Group is is____ . 11. If I f you do a dive to 36 meters (120 feet) feet) for for 9 minutes, your Letter Group is ____ .
Table 2 - Surface interval Time (SIT) Table The longer longer you stay stay on the surface between dives, the more excess ess nitrogen you eliminate. eliminate. Table 2 Surface Interval Interval Time (S (SIT) IT ) Table give gives s you credit for eliminati eliminating ng nitrogen by changing your Lett Letter er Group Group (fig (fig ure 5-9). Table 2 consists of blocks containing containing two num bers. The numbers are expressed expressed as hours and minutes.
Chapter 5- Decompression, Dive Tables, and Dive Computers
A
Y
B
Y
C
Y
D
Y
E
Y
24:00 24:00 24:00 24:00 24:00 0:10 3:21 4:50 5:49 6:35 3:20 4:49 5:48 6:34 0:10 1:40 2:39 3:25 1:39 2:38 3:24 0:10 1:10 1:58 1:09 1:57 0:55 0:10 0:54 0:10
F
V
G
Y
24:00 7:06 7:05 3:58 3:57 2:29 2:28 1:30 1:29 0:46 0:45 0:10
H
Y
24:00 7:36 7:35 4:26 4:25 2.59
2:58 2:00
1:59 1:16 1:15 0:41 0:40 0:10
I
Y
J
V
K
Y
24:00 24:00 24:00 8:00 8:22 8:51 7:59 8:21 8:50 4:50 5:13 5:41 4:49 5:12 5:40 3:21 3:44 4:03 3:20 3:43 4:02 2:24 2:45 3:05 2:23 2:44 3:04 1:42 2:03 2:21 1:41 2:02 2:20 1:07 1:30 1:48 1:06 1:29 1:47 0:37 1:00 1:20 0:36 0:59 1:19 0:34 0:55 0:10 0:33 0:54 0:32 0:10 0:31 0:10
V e r i f y I M V i i u H a v e L e a r n e d
L
V
24:00 8:59 8:58 5:49 5:48 4:20 4:19 3:22 3:21 2:39 2:38 2:04 2:03 1:36 1:35 1:12
24:00 9:13 9:12 6:03 6:02
4:36 4:35 3:37 3:36 2:54 2:53
Review the followin following g questions questions about Table 2: 12. If If you have a Letter Group Group of I and your SIT SIT is 2 hours and 36 36 minutes, your your new Letter Grou Group p is . 13. If If you have a Letter Group of C and your SIT SIT is 3 hours, your new Letter Group Group is . 14. If If you have a Letter Group Group of G and your SIT SIT is 42 minutes, your new Letter Group is .
2:20
2:19 1:50 1:49 1:26 1:11 1:25 0:50 1:05 0:49 1:04 0:29 0:46 0.28 0:45 0:27 0:10 0:26 0:10
F IGI G U R E 5 - 9 . T A B L E 2 - S U R F A C E INI N T E R V A L T IM I M E (S(S I T ) T A B L E .
The lower lower number number in the block is the minimum Surface Interval Time (SIT (SIT)) for a particul particular ar group group and and the uppe upper number is maximum maximum SIT for a partic particular ular group. up. To find your new Letter Group based based on your SIT SIT,, use the follow following ing steps: 1. Look across the top row of the table table unt untilil you you come to the Letter Group designati designation on you had at the end of your previous previous dive. For example, you had a Letter Group of G. 2. Go down the column unt untilil you find find the block into which your SIT fits. For example, example, you you were were out of the water for three hours. hours. The block into which which three hours fits is is the one which which starts at 2:59 and ends at at 4:25. 3. Move left across the row containing containing your your corre corre sponding sponding block until until you come to another letter. For example, if you had a Letter Group of G and were out of the water for for three hours, you would have a new Letter Group of C. Note that the maximum time in this table table is 24 hours. hours. All exces excess nitrogen nitrogen is considered eliminat eliminated ed after you have been on the surface surface for 24hours. Therefore, Therefore, a dive after after 24hours on the surface is not considered considered a repetitive dive.
T a b lel e 3 - R e p e t iti t i v e D i v e l i m e t i l e Table 3 - Repetitive Dive Timetable provide provides s your Adjusted Adjusted Maximum Maximum Dive Time (AMDT) for your next dive and your Residual Nitrogen Time (RNT (R NT)) based on your current current Letter Group Group (figur (figure e 5-10). You use this table twice for each repetitive dive. First, First, you use use the table to find your AMDT AMDT when plannin planning g your dive. Next, you use the the table to find your your RNT after you complete complete your dive. You add add the RNT to your Actual Actual Dive Time (ADT) to find your Total Nitrogen Time (TNT (TNT). ). The table table is arranged arranged with with the depths from from 12 meters to 40 meters (40 feet to 130 feet) feet) in columns columns across the table and the Letter Letter Groups in rows down the table. Each Each block block of the table contains contains two numbers. numbers. The upper number is the RNT RNT corresponding to each depth and Letter Group. Group. The lower, red number is the the AMDT AMDT for each each depth and Letter Group. Use Use the follow following ing steps to find your your AMDT when when planning a repetitive dive: 1. Find Find your new Letter Group, based based on your SIT SIT,, in the column column on the right right side of the table. For example, you have a new Letter Group of C. 2. Search along the row corresponding to your Letter Group until you come to the column corresponding to the depth to which you want to dive. For For example, you want to dive to 15 meters meters (50 feet). feet). 3. Look at the the lower number number to find your AMDT. AMDT. For example, with a Letter Group of C, you can dive to 15 15 meters meters (50 feet) for a maximum maximum of 59 minutes. minutes.
e c o m p r e s s i o n , D i v e T a b l e s , a n d D i v e C o m p u t e r s
NAU I Scuba S cuba D i ver
Use the followi following ng steps to find your your TNT at the end of your repetitive dive: 1. Find Find your new Letter Group, based based on your SIT, SIT, in the column on tthe he right side of the table. For example, you have a new Letter Group of C. 2. Move along the row corresponding corresponding to your your Letter Group Group unt untilil you come to the column correspon ding to your deepest depth depth during during the dive. For example, you went to 14 meters (47 feet), feet), whic which h rounds to 15 meters (50 (50 feet). feet). 3. Read the upper upper number number in the block. This is your RNT. For example, the RNT for a dive to 15 meters (50 feet) for L Letter etter Group C is 21 minutes. 4. Add the RNT to your your ADT to find your your TNT. For example, if your your ADT was 35 minutes, you you must add your your RNT RNT of 21 minutes minutes from step 3to get a TNT of of 56minutes. Notethat the AMDTs and RNTs in in each each block block add up to the circle circled d MDT for each corresponding depth in Table Table 1.
1 2 1 5 1 8 21 4 0 50 60 7 0 7 123 17 113 25 105 37 93 49 81 61 69 73 57 87 43 101 29 116 14 138
6 74 13 67 21 59 29 51 38 42 47 33 56 24 66 14 76 4 87
161
5
2 4 2 7 30 3 3 36 40 NEW 80 90 1 0 0 1 1 0 1 2 0 1 3 0 GROUP
50 11 44 17 38 24 31 30 25 36 19 44 11 52
4 41 9 36 15 30 20 25 26 19 31 14 37 8 43
4 31 8 27 13 22 18 17 23 12 28 7 32
3 22 7
61
3
3 12
3 9
6 9 10 5 13
6 6 9 12
11
16
15
13
20
18
16
< F
26
24
21
19
33
30
27
25
22
43
38
34
31
28
25
57
48
43
38
79
64
54
47
88
72
61
53
18 11 14 16 9 20 5 24
19 7 15 10 12 14 8 18 4 22
29
38
50
70
99 111
3 5 6 8
< A
< D
< E
< H < I
AVOI D
(100’)
F IGI G U R E 5 - 1 0 . T A B L E 3 - R E P E T I T IVI V E D IVI V E T IM IM E T A B L E .
D IV IV E P L A N N I N G W O R K S H EE T
V e r i l y W h a t Y o u H a v e L e a r n e d Review the followi following ng questions about Table 3: 3: 15. If If you have a new Letter Group of D and you want to dive to 18meters (60 feet) feet),, your your AMDT is minute minutes. s. 16. If If you have a new Letter Group of B and you want want to dive to 27 meters (90 feet) feet),, your your AMDT is minute minutes. s. 17. True or False. If you have a new Letter Group Group of G, you can dive dive to 24 meters (80 feet) feet) for for 32 minutes. minutes. 18. If If you have a new Letter Group of E and you dive to 17meters (57 feet), feet), your your RNT is minutes. 19. If you have a new Letter Group of G and you dive to 11meters (37 feet), feet), your RNT is is minutes. 20. If I f you have a new Letter Group of C and you dive to 20 meters (67 feet) for 22 minutes, inutes, your your TNT is minute minutes. s. 21. If If you have a new Letter Grou Group p of D and you dive to 1 6 .2 meters (54 feet) for 18 minutes, your TNT is minutes. minutes. ______
You must systemati systematicall cally y keep keep track of your depth, dive time, surface interva interval,l, Letter Group designations, and other informati information on when you work with the NAUI Dive Tables or NAUI Dive Time Calculato Calculator. r. There is a NAUI Dive Plann Plannin ing g Worksheet Worksheet (figure (figure 5-11) on the back ofyour NAUI Dive Tab Tables. les. This section explains how to use use the worksheet, which which is very useful for help help ing prevent prevent errors. errors. This method method of calcula calculating ting your dive profile method method.. times is called called the profile You can write write on the NAUI worksheet worksheet on your NAUI Dive Tables Tables with a pencil pencil and erase erase it or scour it clean without without damaging damaging the tables. tables. You should use the the work sheet sheet on each dive, so take a pencil with you when you you godiving and write your dive information information directly directly on the NAUI workshee worksheet. t. Your NAUI Dive Tables are also waterproof soyou can record info informat rmation ion on them in the water or refer to tthe he planning information while while you are on your dive. In this section, you w wililll see how to to use use the the NAUI Dive Plan Planni ning ng Worksheet and your NAUI Dive Tables to make or plan two dives in one day. day.
Chapter 5- Decompression, Dive Tables, and Dive Computers
RNT = 0
RNT =
RNT =
ADT =
ADT =
ADT =
TNT =
TNT =
TNT =
F IGI G U R E 5 1 1 . T H E N A U I D IVIV E P L A N N I N G W O R K S H E E T P R O V IDI D E S A N E A S Y W A Y T O K E E P T R A C K O F Y O U R D I V E S .
P l a n n i n g Y o u p D i v e To plan your dive dive with your NAUI Dive Planning Planning Worksheet (figu (figure re 5-12), use use the followi following ng steps: 1. Write your planned planned depth depth on the top line of the left side of the the first first profile. For example, plan a dive to 21 meters (70 (70 feet). feet). 2. Write Write your planned depth depth plus three meter meters s (10 feet) on the lower line line to the left side of th the e first first profile. profile. For example, your planned planned dep depth th plus 3 meters (10 feet) is 24meters (80 feet). feet). 3. Look at Table Table 1 and find the MDT MDT for your planned planned depth. For example, the MDT for 21 meters (70 feet) is 45 minutes. 4. Record the MDT next to to your planned planned depth on the first profile. 5. Find Find the MDT for your pl planned anned depth plus 3 meters (10 feet). feet). For example, the MDT for 24 meters (80 (80 feet) is 35 minutes. 6. Record the MDT next to your planned depth plus 3 meters (10 feet) on the first profile. profile. At this point, you have finished planning planning your dive with regard to depth depth and time limits. limits. Now Now it’s it’s time to dive your plan.
Use the followin following g steps to find your your Letter Letter Group: 1. In In the time slot at the upper left comer comer of the first profile, profile, record record the time that you started your your descent. For example, your first first dive started started at 9:45 a.m. 2. On the line to the the lower right right side of the first profile, profile, record your dee deepe pest depth. depth. For example, you went to 20 meters (66 feet) feet).. 3. In In the time slot at the upper right right corner of the first first profile, profile, record the time you completed completed your ascent. For example, you surfaced surfaced at 10:20 a.m.
F i n d i n g Y o i p L e t t e r G r o u p The next next step using your NAUI Dive Plann Planning ing Worksheet is to record record the the infomia infomiation tion from your first dive and find find your Letter Group designation (figu (figure re 5-13).
F IGI G U R E 5 1 2 . T H I S P R O F I LEL E H A S B E E N C O M P L E T E D F O R A D IVI V E P L A N N E D T O 2 1 M E T E R S (7( 7 0 F E E T ) .
NA UI Scuba Sc uba D i ver
r e t u p m o C e v i D d n a , s e l b a T e v i D , n o i s s e r p m o c e D
4. At the the bottom of the first profile profile (next to ADT), record your your ADT. Remember to subtract your three minute precaution precautionary ary decompression decompression stop, which is considered considered neutral neutral time. For example, your total total dive time was 35 minutes - subtract ing the three minute precaut precautiona ionary ry stop stop gives you an ADT of 32 minutes. minutes. 5. Add your your ADT to the RNT RNT to get your TNT. For example, example, because because this was your first dive of a trip, trip, your RNT is 0 (zero) (zero),, so your TNT is 3 32 2 minutes minutes plus 0 minutes for a total of 32 minutes. 6. On Table 1, find the row corresponding corresponding to your deepest depth and follow follow the row across to the block containing the time corresponding to your TNT. For example, example, your depth was was 20 meters (66 feet), feet), whic which h rounds up to 21 meters (70 feet) and you follow the row over to to 32 32 minutes, which which rounds up to the the 35 minute minute block. 7. Trace the column conta containi ining ng the appropriate time dow down until you reach reach a letter. letter. This is your Letter Group. For For example, for a dive to 21 meters (70 feet) for 35 minutes, your your Letter Group is G. 8. Record the Letter Group on the line line above the time you completed your dive. This completes completes the dive profile profile for your first first dive.
F IGI G U R E 5 1 3 . T H I S P R O F I LEL E ISI S C O M P L E T E F O R A D IVI V E T O 2 0 M ETERS (66 FEET) FOR 32 M INUTES.
R e c o r d i n g Y o u r S u r f a c e Interval a n d F ini n d ini n g Y f e u r N e w t e l lel e r G r o u p Once you have comple completed ted your firs firstt dive, you must spend at least 10 minutes on the surf surface ace to avoid avoid count count ing two dives as as one. The length of your Surface Surface Interval Interval Time (S (SIT) IT ) will determine what your new new Letter Letter Group Group will will be for planning planning your next dive (figure (figure 5-14). Use Use the following following steps to find your your new Letter Group Group after after you have completed your SIT: SIT: 1. Record your SIT SIT in in the time slot to th the e right right of your Letter Group. Group. For example, your SIT SIT is 2 hours. 2. Find Find your your Letter Group in the row of letters letters between Table 1and Table 2. For example, you had a Letter Group of G.
134
B E T W E E N Y O U R L E H E R G R O U P FR FR O M Y O U R P R E V IOI O U S D IVI V E A N D Y D U R N E W L E T T E R G R O U P .
3. Look down own the the column until until you find the block into which your SI SIT T fits. For example example, you are on on the surface surface for 2 hours. The block into which 2 hours fits fits is is the one that that ranges from 2:00 to 2:58.
Chapter 5- Decompression, Dive Tables, and Dive Computers
4. Move across across the row contai containing ning your correspon ding block to the left unti untill you come to another letter. For example, you you had a Letter Group of G and you have been on the surface surface for for 2 hours, so your new Letter Group is D. 5. Record the newLetter Group to the right right of your SIT. SIT. Onceyou have determined determined your new Letter Letter Group, you are ready to plan plan a repetitive repetitive dive.
Planning Your Repetitive Dive When planning planning repetitive dives, you use use the NAUI Dive Plannin Planning g Worksheet Worksheet as you did for the first dive (figu (figure re 5-15). However, you must use Table Table 3 to find your AMDT when when plannin planning g your dive. Use the followi following ng steps to plan plan a repetitive repetitive dive: 1. Write Write your planned depth on the top line line to the left of the second profile. profile. For example, example, plan plan a dive to 15meters (50 (50 feet). feet). 2. Write Write your planned planned depth plus three three meters (10 (10 feet) on the lower line line to the left of the second profile. profile. For example, example, your planned de depth pth plus three meters (10 feet) is 18 meters (60 feet). feet). 3. Look at Table Table 3 and find find the AMDT for your
( 5 0 F E E D H A S B E E N C O M P L E T ED ED O N T H I S W O R K S H E E T .
planned planned depth. For example, the AMDT for 15 meters (50 feet) for Letter Letter Group D is 51 minutes. 4. Record the AMDT next to your your planne planned d depth on the second profile. profile. 5. Find Find the AMDT for your planned planned depth plus 3 meters (10 feet) feet).. For example, the AMDT AMDT for 18 meters (60 feet) is 31 minutes for for Letter Group D. 6. Record the the AMDT next to your your planned planned depth plus 3 meters (10 feet) on the second second profil profile. e. At this time, time, you have finished planni planning ng your repet itive itive dive regarding depth depth and time limits. limits. Now it’s it’s again time to dive your plan.
R e c o r d i n g Y o t iri r R e p e i ili l i vev e D i v e Recording your re repetitive petitive dive is simi similar lar to record record ing your first dive. Howeve However, r, this time you have residual residual nitrogen in your your body and you must consider that before you find your new Letter Group (figur (figure e 5-16). Use Use the followin following g steps to record your repetitive repetitive dive and fin find d your new Letter Group: Group: 1. In In the time slot at the upper left comer comer of the second second profile, profile, record the time that you started your descent. For example, your second dive started started at 12:35 p.m. 2. On the line line to the right right side of the second pro file, file, record your deepest epest depth. depth. For example, you went to 1 6 meters (52.5 feet). feet). 3. In the time slot at the upper upper right right comer of the first first profile, profile, record the the time you completed completed your ascent. For example, you surfaced at 1:05p.m. 4. Record your your ADT at the bottom of of the second second profile profile (next to ADT). ADT). Remember to subtract your 3 minute precautionary decompression stop, stop, which which is considered considered neutral neutral time. For example, your tota totall dive time was 30 30 minutes subtracting subtracting the 3-minute 3-minute precaution precautionary ary stop stop gives you an ADT of 27minutes. 5. Find Find your your RNT RNT for your depth depth and Letter Group on Table 3- For example, example, you had a Letter Group of D and you went to 16 meters (52.5 feet), feet), which which gives you an RNT RNT of 24 minutes. 6. Record the RNT at the bottom of the second second profile (next to RNT). RNT).
c o m p r e s s i o n , D i v e T a b l e s , a n d D i v e C o m p u t e r s
II IIS S
NAU I Scuba Uiver
Plan Planni ning ng Worksheet provides provides a convenient convenient way to record record your data. Get into the habit of recording your dives on the workshe worksheet, et, and it will ill become easy to keep track of your diving. This will will also make make it easier to complete plete your logbook at the end of the day.
V e r i l y W h a t Y o u H a v e L e a r n e d
T O I B M E T E R S ( 5 2 .5.5 F E E T ) F O R 3 0 M I N U T E S .
7. Add your ADT to your your RNT RNT to get your TNT. For example, your ADT is 27 minutes, minutes, plus plus an RNT RNT of 24minutes, minutes, gives you a TNT of 51 minutes. 8. Go back to Table 1 and find the row correspon ding to your your deepest depth. Follow Follow the row across to the block containin containing g the time corre sponding to to your TNT. For example, your depth was 1 6 meters (52.5 feet), feet), whic which h rounds up to 18 meters (60 feet) and your TNT was 51 min min utes, which rounds up to the 55 minute block. 9. Look down the column contai containin ning g the appro priate time until you reach a letter. letter. This is your Letter Group. For example, for for a dive to 18 meters (60 feet) for 55 minutes, your your Letter Letter Group is I. 10. Record the Letter Group on the line line above the time you completed your your second dive. This completes the dive profile for your second dive. Use the same steps to plan plan and perform perform a thir third d dive. Do not rely rely on your memory to keep track of of dive surface inter interval vals. s. You times, maximum maximum depths, or surface must record this inform informatio ation, n, and the NAUI Dive
Review the following following problems using the NAUI Dive Planni Planning ng Worksheet Worksheet and your NAUI Dive Tables: Tables: 22. Your Your first first dive dive of the daywas to 20meters (66 (66 feet). feet). You descended at 9:40, surfaced surfaced at 10:19, and and com pleted a three-minute precautio precautionary nary decompres sion stop(ADT=36). stop(ADT=36). Your seconddive was to 14 meters (46 feet). feet). You descendedat 12:32, surfaced at 1:13, and completed a three-minute precaution precaution ary ary decompression stop(ADT=38). stop(ADT=38). Your third third dive was to 12meters (40 feet) feet).. You descendedat 2:43, surfaced at 3 :2 6 , and completed a tthree-minute hree-minute precaut precautiona ionary ry decompression stop(ADT=40). 23. Your first first dive of the firs firstt day of your trip trip was to 24 meters (80 (80 feet). You descended at 8:35, surfaced at 8:58, and completed a three-minute precauti precaution on ary decompression stop(ADT=20). stop(ADT=20). Your SIT SIT was two hours and 46minutes. Your second dive was to 16meters (52.5 feet) for 36minutes incl includ udin ing g your precautionary precautionary decompression stop(ADT=33 stop(ADT=33). You surfaced at 12:20. Your Your third third dive was to 10 meters (33 feet). feet). You descended at 3:10, surfaced at 4:10, and completed a three-minute precauti precaution on ary decompressionstop(ADT=57).
M A X IM I M I Z IN I N G Y O U R U N D E R W A T E R T IM IM E There are times when you you are making making repetitive repetitive dives that you will will either not be able to dive to the d dep epth th you would like or for the length of time you would like. You can maximize maximize your underwater time and depth to which you want to dive dive by adjusting your SIT SIT,, your depth, depth, or your ADT. In this section, you wi willll see how the three three factors interact interact and how how working with them them will will get you the depth or time you want. want.
Chapter 5- Decompression, Dive Tables, and Dive Computers
L i m i t i n g Y o u r D i v e l i m e The first way to keep within within the Maximum Dive Time is easy easy- limit limit your ADT. Your first dive of the day must not exceed the MDT for the depth of that di dive, ve, and your repetitive repetitive dives must not exceed exceed the AMDT for your planned dep depth. th. This can be restrictive. Suppose you want want to make three 25 minute minute dives dives to a depth of 18 meters (60 (60 feet feet). ). You want to spend an hour on the surface surface betwee between each dive. Your first first dive is to 18meters (60 feet) feet) for 25 minutes so your your Letter Group is E. After After a SIT SIT of 1hour, 1 hour, your new Letter Group is D. With a Letter Group of D, your AMDT for a dive to 18 meters (60 feet) is 31 minutes. If your your ADT for the second dive to 18meters (60 feet) is 25 minutes, minutes, your your RNT is 24, and your TNT is 49. Your Letter Group Group fol fol lowing this dive is H. After After another hour of SIT, SIT, your new Letter Group Group is G. According to Table 3, the maximum time you can spend at 18meters (60 feet) feet) is is 11 minutes. minutes. You can see that that making making three three back-to-back dives to depths of 18 meters (60 feet) or more can be quite quite limiti limiting ng if you want to spend the maximum amount of time time in in the water.
Planning Your Surface Intervals Planning your surface intervals carefully is a good way to control your residual nitrogen and your AMDT for repetitive dives. dives. The longer you remain on the sur face between dives, the less nitrogen nitrogen remains remains in in your your body body,, and the longer you can stay under water on your next dive. You must be able to determine how long a surface interval interval is required to carry out a planned dive without nearing the no-decom no-decompression pression limits. limits. Surface interval intervals s must be at least 10 minutes in length. NAUI recommends that that you spend at least an hour on the surface between dives. Choosing to spend spend more than an hour hour on the surface surface between between dives gives you more more time to offgas nitrogen and will will give you more more time under water on your next dive. If you use the same example from the previous previous sec tion, you have a Letter Group of H after after your second dive dive of the day. For your third third dive, dive, you want want to go to 18
meters (60 feet) for a att least 25 minutes. If you look at the 18-meter (60-foot) column column on Table Table 3, you see that you must have a Let Letter ter Group of E to be able to spend a maximum maximum of 25minutes minutes at 18 meters (60 (60 feet). feet). To find out how long you must stay on the surface surface to change from a Letter Group of H to a Letter Group of E, follow follow the E row from Table 3 back to Table 2. At the same time, foll follow ow the H column column down from Table Table 1. Find Find the block where where the E row and H column intersect. It should have a minimum time of 1:42 and a maxi mum time of 2:23 2:23. By spending one hour and 42 min min utes on the surface surface between your second and third third dives, you can dive to 18meters (60 feet) for 25 minutes.
Limiting Your Depth Your third option in dive planning is to increase increase your bottom time by limiti limiting ng your depth. depth. If you were were not able to extend extend your surface surface inte interva rvall between between the the second and third third dives in the previous example and you did not want to make a dive shorter than than 25 minutes, minutes, you could could dive to a shallo shallower wer depth and spend more time there. If you have a Letter Group Group of G following a one hour SIT and you know youwant to spend at least 25 minutes on your dive, follow the G rowin Table 3 until you find a column column that has an AMDT of at least 25 minutes. In this example, the depth of 12meters (40 feet) feet) has an an AMDTof 57minutes. Therefore, by diving diving six meters (20 feet) shal shal lower, you can make a 25 minute minute dive. These examples showhow you can use the dive tables to your advantage.
c o m p r e s s i o n , D i v e T a b l e s , a n d D i v e C o m p u t e r s
S P E C I A L R U L EESS There are a number of special rules and procedu procedures res you must must also learn to handle special situations. situations. These situations situations includ include e decompression, pression, cold or strenuou strenuous s diving, flying flying after diving, and altitude diving.
Decompression Diving Intentio Intentional nally ly exceeding exceeding the Maximum Dive Time is unwise, unsafe, unsafe, and discouraged. discouraged. As you will will learn learn in
137
NAUI Scuba D i ver
s r e t u p m o C e v i D d n a , s e l b a T e v i D , n o i s s e r p m o c e D
advanced advanced or specialty tra traini ining ng for for deep diving, diving, you must meet many requirements requirements to carry carry out decompression dives dives properly. properly. In normal recreational recreational diving ■ S a decom decompressio pression n dive dives s are still still discoura discouraged ged,, even if you meet all the requiremen requirements. ts. Diving Diving is only a sport - why risk injury? technical diving divin g , an extreme Some divers engage in technical ly advanced nced recreational diving activity. Technical Technical diving can involve involve planned planned decompression dives. You must have special equipment and trainin training g as well well as extensive diving diving experience erience toparticipate. In addition, this type of diving is much more more hazardous than other rec recreational reational diving. Technical Technical divers accept accept the fact that risk of DCS or other problems is much greater.
Precautionary Decompression Slops You should sto stop p at 5me 5 meters ters (15 feet) for 3 minutes precautionary decomp decompre res s y j at the end of each ach div dive for for a precautionary sion sion sto stop p or safety stop stop.. Taking this action is recom or safety recom mended ended to help prevent DCS DCS and to maint maintain ain control control of your ascent ascent near the surface. Time spent decompressing is considered neutral time. It does not count as as part of your ADT ADT.. For exam ple, if you dive to 21 meters (70 feet) feet) for for 45 minutes, you should should stop at 5me 5 meters (15 feet) for for an additio additional nal 3 minutes. However, you determine your Letter Group using the dive dive schedule schedule of 21 meters/45 minutes (70 feet/45 minute minutes). s). You can also also includ include e the 3 minutes as part of your ADT a as s an extra extra precaution. precaution. You document document your precaution precautionary ary decomp decompression ression stop on your NAUI Dive Plann Plannin ing g Worksheet Worksheet next to to a short horizontal horizontal line line drawn through th the e ascent line line of the dive profile. profile.
Required Decompression If you accidenta accidentally lly exce exceed ed a Maximum Div Dive e Time or Adjusted Adjusted Maximum Dive Time, you must decompress by stages. You must stop at 5 meters (15 (15 feet) during during your ascent and stay there for a specified time to allow allow your body to to offgas offgas nitrogen. You must keep your physical activity activity to a minimum during your decompression decompression stop.
138
J
F IGI G U R E 5 1 7 . I T I S U S E F U L T O H A V E A M E A N S T O H E L P M A I N T A I N A C O N S T A N T D E P T H D U R INI N G Y O U R D E C O M P R E S S I O N S T O P .
It is useful to have a means of support support to maintain maintain a constant depth depth during during your stop. stop. An ascent ascent line, a decompression bar suspended from a boat, or the con con tour of the bottom bottom in shallow shallow water are all all examples examples of support support (figur (figure e 5-17). 5-17). Without Without something to grasp, it is difficu difficult lt to remain at one one depth depth in shallow wate water. r. Swimming Swimming and hovering hovering decompression decompression are possible, possible, but not easy, easy, and the activi activity ty might might offset the the benefit of offgassing nitrogen. Table 1gives you required decompressio decompression n times for each depth. depth. To the right right of the Maximum Dive Times for each depth depth are split split squares containin containing g two set sets s of numbers. The top number represents represents dive time. The lower number number represents the de decompression compression time required for that dive time. The decompressio compression n time is the length of of time you must spend at 5me 5 meters (15 feet) to help avoid DCS. For example, if your your TNT on a 24meter (80-foot) (80-foot) dive dive was 45 minutes, you would have to perfonn perfonn a 10-minute decompression decompression stop. Time Time spent decompressing is considered neutral time. It does not count as part of your ADT ADT. You docu docu ment your requir required ed decompression stop stop on your NAUI Dive Plannin Planning g Workshee Worksheett next next to a short horizontal line drawn through the ascent line of the dive dive profile.
Omitted Decompression If you surface and and discover you omitted a required
Chapter 5- Decompression, Dive Tables, and Dive Computers
decompression stop, take the the follow following ing steps: 1. Discontinue Discontinue divi diving ng for 24 hours no matter how well you feel. 2. Breathe 100% oxygen, if availab available. le. If only a small, small, portable unit unit is availab available, le, breathe the oxy gen until until the cylinder cylinder is depleted depleted.. 3. Drink Drink plenty of fluids. 4. Rest. 5. Watch Watch for symptoms of DCS. If you suspect that that you have DCS, you must seek medical help. help. If there there is an operational chamber chamber near by, go there. Otherwise, have medical medical help call call Divers Alert Network Network (DAN) at (919) (919) 684-9111, which which is their their 24-hour emergency emergency line. They will will advise you of the procedure to follow to obtain chamber treatment. Never goback into into the water to try to make up for the omitted decompression stop.
means that the rate rate of change in in pressure is greater when you descend into water at altitude. altitude. To account for this dif ference, you needto use altitude altitude conversion tables or the NAUI Altitude Tables and follow follow special procedures. Before you dive dive at altitu altitudes des above 300 meters (1000 feet), you must be trained in special altitude diving pro cedures. Your table table depths, maximum rate of ascent, ascent, and the depths for decompression stops change with with alt altii tude. Your depth gaug gauge e will ill also give incorrect incorrect data. data. If altitude diving is common in your area, your instructor might pro provide vide additional information as part of your course, and also also might recommend that you participate in a high-altitude specialty-training program program before before you receive your NAUI Scuba Scuba Diver certifica certification. tion. High-altitude trai trainin ning g is beyond the scope of this text book. Donot attempt high-altitude divi diving ng without first completing an appropriate high-altit high-altitude ude traini training ng program.
C o lil i i o r S t rer e n u o u s D i v e s If you getcold, do strenuous strenuous physical work during during or after a dive, or both, use the next greater time for your dive schedule. For For example, a dive to 18meters (60 feet) with with a TNT of 40minutes would would become a 50minute minute dive.
Flying alter Diving If you you decrease pressure below one ATM by going to an altitude above sea level after diving, diving, you increase increase your risk of suffering DCS. Commercial planes pressur pressur ize their cabins to an altitude altitude equivalent equivalent to about 2400 meters (8000 feet) or 0.75 ATM or less. If you only only do one no-decom no-decompression dive, you can can fly after waiting waiting 12 hours. If you do mo more re than one no decompression ression dive in a day, or do multi multiple ple days of div ing, you should wait wait longer. The current recom recomme mendanda17^1 tion is to wait 24 hours after the completion of your last last dive. If you make make dives dives that require require a decomp decompression ression stop, or you omit a required required decompression decompression stop, wait wait more than 24 hours before flying. flying.
A l t i t u d e D i v i n g Atmospheric pressure decreaseswith with altit altitude, ude, whic which h
U S IN IN G T H E N A U I D I V E T I M E C A L C U L A T O R The NAUI Dive Tables are the basis for the NAUI Dive Time Calculator, which eliminates some calcula tions required with the tables tables (figu (figure re 5-18). Once Once you you are famili familiar ar with the NAUI Dive Tables, Tables, learning learning how to to use the NAUI Dive Time Calcul Calculato atorr is easy. easy.
General Organization NAUI Dive Tables 1and 3 are combined combined on the baseplate. baseplate. Letter Group designations appear around the the circumference, circumference, and ADTs in minutes appear in the win dow. End-of-Dive Letter Letter Groups appear to the right right of the ADT numbers in the disk window. Dive Table Table 2 is printed on the disk.
Using the Calculator To plan your your first dive of the da day, y, use the following steps: 1. Find Find the No Group section on the baseplate. 2. Align the depth arrow on the edge of the disk with with the planned depth of your dive. The Maximum Dive Time for that dive appears appears as the the
m
NAUI Scuba Diver
F IGI G U R E 5 1 8 . T H E N A U I G I V E T I M E C A L C U L A T O R E L IM IM I N A T E S S O M E CALCULATIONS REQUIRED BY THE NA UI DIVE TABLES.
largest number number in the window window.. For example, example, a No Group diver who plans plans a dive to 18 meters (60 feet) would have a Maximum Dive Time of 55minutes minutes.. To find your Letter Group at the completion of your dive, use the follow following ing steps: steps: 1. Find Find the No Group section on the baseplate. 2. Align Align the depth arrow on the edge of the disk with with the deepest depth of your your dive. 3. Read the bottom times from the center center of the disk outward outward and find the first time that you do not exceed. 4. Look to the right right of the window to see your EndOf-Dive Letter Group. For For example, if if you do a dive to 18 meters (60 (60 feet) feet) and your your ADT is 23 minutes, the first first time you do not exceed is 25 minutes. The End-Of-Dive Letter Group next to the 25 is E. To plan a repetitive dive, use use the following following steps: 1. Use Dive Table Table 2 on the disk to find find your new Letter Group Group after your SIT SIT.. 2. Find Find your your new Letter Gro Group up on the circumference of the baseplate and align align the depth arrow on the disk with the planned depth of your repetitive dive. For example, if you have a Letter Group Group of E and do a 1hour 1 hour SIT SIT,, your new Letter Group Group is D. If you want want to return return to 18 meters (60 feet), feet), align your arrow with the 18 meters (60 feet) depth in the D Group section. The longest time
lim limit in the window is 31 minutes. minutes. To find your End-OfEnd-Of-Dive Letter Group for a repeti tive tive dive, use the followi following ng steps: 1. Find Find your your new Letter Group on the circumference of the baseplate and alig align n the depth arrow on the disk with with the the deepest depth of your repetiti repetitive ve dive. For example, example, align align your arrow with the 18 meters (60 feet) depth in the D Group section. 2. Read Read the bottom times from the center center of the disk outward and find the first first time that you do no nott excee exceed. For example, if if you do a repetitive dive to 18meters (60 feet) with with a Letter Group of D and your ADT is 23 minutes, the first first time you do not exceed is 26minutes minutes.. 3. Look to the righ rightt of the window to see your your EndOf-Dive Letter Group. For example, the the End-OfDive Letter Letter Group next to the 26 is H. The calculator calculator design eliminates the AMDT. It also eliminate eliminates s adding adding the ADT to the RNT to obtain a TNT. However, the answers are the same as those obtained from the dive schedules using the NAUI Dive Tables.
D i v e P l a n n i n g w i tht h t h e C a l c u l a t o r You can use the the NAUI Dive Time Calcula Calculator tor to achieve achieve the same three three methods of dive plann plannin ing g as you can using using the NAUI Dive Tables: • Limit Limit your bottom bottom time to the the maximum number indicated indicated for for a given depth depth and group. • Extend your surface inte interva rvall to move move to a group group letter earlier earlier in the alphab alphabet. et. • Dive to a shallower shallower depth. For example, you are a diver with a Letter Group of of F and you want to dive for 25 minutes. You move the window back and forth and find find that that you can dive dive to 18 meters (60 feet) for 19 minutes minutes or to 15 meters (50 feet) for 33 minutes. To avoid exceeding the Maximum Dive Time, Time, you know you can dive dive no deeper deeper than 15 meters (50 feet) and stay no longer than 33 minutes. minutes. You want to dive to 18meters (60 feet) for 25 min min utes, but cannot cannot because you are a diver in in Letter Group F. You need need to determine determine the the Letter Group Group that wil willl allow allow you to make the dive. You also need to determine the minimum surface interval interval that would allow you to to
Chapter 5- Decompression, Dive Tables, and Dive Computers
achieve that Letter Group. To determine the group group that will ill allow allow you to make the the dive, dive, alig align n the depth depth arrow with with 18meters (60 feet) feet) in in group F. Wor Work k back, one Letter Group at a time, real realign igning ing the depth depth arrow with 18 meters (60 feet) for for each group, group, unt untilil you find find a Maximum Dive Time of 25 minutes minutes or longer. In this example, the first first Letter Group Group allowin allowing g a Maximum Dive Time of 25 minutes is E. E. In some instances, the words DO NOT DIVE appear in the calcula calculator tor window. This means that you have too too much residual nitrogen to permit a dive at at the depth depth selected for a parti particul cular ar Letter Group. Group. You will ill have to exten extend d your surface inter interval val to dive at that depth, or dive at a shallower shallower depth. depth. Required decompression information is handled differently using the NAUI Dive Time Calculator Calculator than with with the NAUI Dive Dive Tables. A separate Decompression Timetable is provided. provided. To use this table, use the follow follow ing ing steps: 1. Look in the first column corresponding to th the e depth of your dive. 2. Look in in the second second column for your depth for the first first time that equals or exce exceed eds s your ADT in excess of the the Dive Time limit limit for your depth. depth. For example, you can dive to 24 meters (80 feet) for a MDT of 35 minutes. minutes. If your ADT was 38 min utes, your excess time is 3 minutes. The first first time that that equals equals or exceeds your excess time in column column two is 5 minutes. 3. Decompress at 5mete 5meters (15 feet) for the time indicated in column three. As you you can see, using using the NAUI Dive Time Calculat Calculator or is even easier than than using using the NAUI Dive Tables.
S A M P L E P R O B L EM EM S Use the NAUI Dive Dive Tables or the NAUI Dive Time Calculat Calculator or to solve the following following dive profiles: profiles: 1. Your first first dive of the day is planned planned for a depth of 18meters (60 feet), feet), begins at 9:30 a.m., and lasts for 23minutes. The actual actual depth of the dive is 16.7 meters (55 feet). You make a precautio precautionary nary
decompression stop at 5mete 5 meters (15 feet) for 3 minutes, you surface at 9:56 a.m. a.m. and remain remain out of the water unt untilil 10:40 a.m. Your next dive is to a depth of 15 meters (50 feet) feet) for for 23 minutes. You make a precautio precautionar nary y decompression stop stop at 5meters (15 feet) for 3 minutes. You surface at 11:06 a.m. and have a SI SIT T of 1hour and 50 min min utes. At 12:56 p.m., you begin begin your your third third dive dive to a planned planned depth of 12 meters (40 (40 feet), feet), but you end up reachin reaching g a depth of 13.7 meters (45 feet) with with an ADT of 30 minutes. You make a precaut precautiona ionary ry decompression stop at 5mete 5 meters (15 feet) for 3 minutes and you you surface from the third dive dive at 1:29 pm. pm. What is your fina finall Letter Group? Group? 2. Your firs firstt dive of the day begins at 8:00 8:00 a.m. and is to a depth of 18 meters (60 feet) feet) for 31 min min utes. You make make a precaution precautionary ary decompression pression stop at 5meters (15 feet) ffor or 3 minutes. minutes. You sur face at 8:34 :34 a.m. Your SIT is 1hour 1 hour and 31 min min utes. The second dive begins at 10:05 a.m., is to a depth of 1 6 .8 meters (55 feet) feet),, and lasts for 24 minutes. You make make a precaution precautionary ary decompres sion stop at 5met 5 meters ers (15 feet) for for 3 minutes minutes and surface at 10:32 a.m. Your third dive, which
e c o m p r e s s i o n , D i v e T a b l e s , a n d D i v e C o m p u t e r s
begins at 12:36p.m., is to 15meters (50 feet) feet) for for 31 minutes. What time time do y you ou surface from this dive and what is your Letter Group? 3. Your firs firstt dive is to 18meters (60 feet) feet) for 30 minutes followed by a 30-minu 30-minute SIT. SIT. The sec sec ond dive is to 15 meters (50 feet) feet) for 30 minutes. What is your Letter Group after the second second dive? 4. Your first first dive dive is to 17 meters (56 feet) feet) for 31 minutes minutes and it is followed followed by by a 1hour 1hour SIT. SIT. The second dive is to 16 meters (52.5 feet). feet). What What is the AMDT for the second second dive? What What is your Letter Group if if you reach reach the AMDT? AMDT? 5. After the second second dive in problem problem 4, how long a SIT is required to make make a 25-minute 25-minute dive to 15 meters (50 feet) withou withoutt exceeding the the AMDT? What is your Letter Gro Group up following the third dive if your ADT is 25 25 minutes?
141
NA UI Scuha D i ver
U S IN I N G O IV IV E C O M P U T E R S
e t u p m o C e v i D d n a , s e l b a T e v i D , n o i s s e r p m o c e D
142
There are three ways to determine determine how long you can dive and then ascend ascend withi within n the dive time lim limits. its. We have already already discussed two. The third third and easiest way is to use use a dive computer (figure (figure 5-19 5-19). This is is also the most expensive way to monitor monitor your bottom times, but it is used by more divers every every day. Different Different body tissues absorb absorb and release nitrogen nitrogen at different different rates. rates. Mathematical models (programs) con sidering theoretical tissues have been developed to esti mate ingassing and outgassing from various various tissues. Dive computers puters with these mathematica mathematicall models contin contin uously sample sample depth and time and cal calcula culate te the amount of nitrogen in in each tissue model model for any given moment. The computer computer uses this infor informatio mation n to determine determine the time limits limits for for the current dept depth h and displays it fo forr the diver. Remember Remember that both dive table tables s and dive comput ers are only theoretic theoretical al models of what happens happens in the human body. No presently presently available available method method of calcu calcula lat t ing your excess nitrogen accurate accurately ly accounts for your individ individual ual age, age, body body type, pe, level of fitness, fitness, fatigue, fatigue, drug or alcoho alcoholl use, and so on. Dive tables tables provide provide time limits limits in increments of 3 meters (10 feet) feet) of depth and assume that you spend the entire dive at at the deepest depth. This is one disad vantage vantage to the use use of the tables as compared to a dive computer. computer. A dive computer computer might calculat calculate e both ingassing and offgassing offgassing in increments increments as little little as 0.3 0.3 meters (1 foot) for the depth at which you are diving. diving. The computer constantly constantly recalculate recalculates s as your depth depth changes changes during during your dive. A dive dive computer computer does not count all of your dive time as having having occurred at your deepest depth. When you spendpart of your dive iin n water shallower shallower than than your maximum maximum depth, a dive computer considers this. The computer computer calculates calculates only only the amount of nitrogen that its mathematical mathematical model predicts you ingas ingas or offgas at each depth. A dive computer computer allows a dive with time dive spent at shallower shallower depths (ca (calle lled d a multilevel dive profi profile) le) to have longer dive time limits. limits. Also, Also, there is a lesser lesser penalty for residual residual nitrogen nitrogen than than when you use the fixed-calcula fixed-calculation tion dive tables. tables. Adive computer computer is an electroni electronic c device that can
F IGI G U R E 5 1 9 . T H E R E A R E M A N Y D I F FEF E R E N T T Y P E S O F D IV E C O M P U T E R S .
fail fail without without warning. Mo Most st dive dive computers are highly reliable, reliable, but you you must always cons consider ider this possibility. When a dive compu computer ter fails, your only option option is to sur face at the the rate of ascent specified by by the manufacturer manufacturer and make a 3 to 5 minute minute precau precautio tionar nary y decompression stop at 5 meters (15 feet). feet). Then you must stop diving diving for the period recommended ended by the the manufacturer. manufacturer. You must do this because because there there is usua usually lly no way to recalcu recalcu late your your previous dive or d dives ives using tables. Also, you you cannot start with a fresh computer when you have residual residual nitrogen nitrogen in your system system. There are dive tables availabl available e that that you can use to to compute compute multilevel multilevel dives. dives. The manual plannin planning g and execution execution of these dives dives is complex and not recommend recommend ed for recreational recreational diving. If you want to receive receive credit for reduced nitrogen absorption during multi multilev level el dives, dives, use a dive computer. However, using using a dive computer increases the nee need d for understanding understanding and being being able to work the dive dive tables.
m
D iv e C o m p u t e r T e rm s You must must be famil familia iarr with the terms terms associated associated with dive computers. Aceiling is the shallowest shallowest depth depth to 17^ which which you can ascend without without risk risk of forming bubbles bubbles in your your body body (figu (figure re 5-20). You must not pass orviolate
Chapter 5- Decompression, Dive Tables, and Dive Computers
display, or even log, your dives on your computer. This section describes a typical dive computer and explains explains the most common screens screens and functions. functions. Your computer might be different different and not functio function n in the same way. It might might also use the same terms with with different meanings. You must must read and understand the manual manual that that is supplied with your your computer. computer.
Initialization When a dive computer computer is first first turned on, it it must ini tialize itself. This is a process cess where where the operating pro gram is checked and loaded into the computer’s memory. When this happens, the computer computer typica typically lly runs runs through a self-diagnostic self-diagnostic test and and checks checks all of its functions. The computer display fill fills s during this this sequence ence to ensure that the entire display display is working (figure (figure 5-21). Also, Also, any alarms that the computer computer has has will will display or sound. You can turn on a allll computers puters manually manually to check check their their operation. Some Some computers computers must must be turned on
F I G U R E 5 - 2 0 . T H E C E I L ININ G D I S P L A Y INI N D I C A T E S T H A T Y O U M U S T M A K E A D EC E C O M P R E S S I O N S TO TO P .
this ceiling. If your your computer puter display displays s a ceiling, you have entered a decompression situat situation ion.. To help avoid suffering suffering DCS, you should use your computer computer to prevent a ceiling from being established. Scrolling occurs occurs when your computer continuously continuously flashes the Maximum Dive Dive Times in sequence for pro pro gressively deep deeper depths. This feature feature is an aid for for dive planning planning and for chamber treatment, treatment, should you devel op DCS. Scroll Scrolling ing can can also show your current current dive profile history.
Displays Although many different dive com computers puters are avai avail l able, many share share the same functions. The layouts of the display screens differ differ among computers, but they all all display much of the same information. information. Many dive computers will ill also interfac interface e with a per sonal computer computer so that you can download and visual visually ly
F IGI G U R E 5 - 2 1 . A D I V E C O M P U T E R D I S P L A Y W I LLL L LIL I G H T U P C O M PLETELY OURING INITIALIZATION.
r e t u p m o C e v i D d n a , s e l b a T e v i D , n o i s s e r p m o c e D
F I G U R E 5 2 2 . W H E N A C O M P U T E R I S INI N D I V E M O D E , I T W I L L D I S P L A Y D A TA T A SU SU C H A S Y O U R C U R R E N T D E P T H , M A X I M U M
A M O U N T O F A I R L E F T I N Y O U R C Y L I N D E R A S W E L L
DEPTH, WATER TEMPERATURE, ACTUAL DIVE TIME, AND
A S T H E A M O U N T O F A I R T I M E Y O U H A V E L E F T .
THE TIME YOU HAVE LO T AT YOUR CURRENT DEPTH.
with a switch before before you enter the water. Other comput comput ers turn on automatica automatically lly when you you enter the water. water. You must must initia initializ lize e your computer computer to check check its oper oper ation before before you begin begin your dive. If you must must turn your computer on with with a switch, do not not turn it on at depth, or after you have started your descent, descent, because because your dive will ill not be be recorded accurately. accurately. You can damage som some computers by turning turning them on at depth.
Scrolling All computers computers can scroll before before diving (after (after they are initial initialize ized) d) and betwe between en dives. dives. Between dives, dives, the computer computer accounts for your residual residual nitrogen and the time you have been been on the surface. It shows your Allowable Maximum Dive Time for your next dive for each depth programmed in the the computer. This This is called scrolling. Some computers puters will will scroll continuously continuously while while you are on the surface. Once Once they have scrolled through through the
144
F IGI G U R E 5 2 3 . A N A I R -I- I N T EG E G R A T E D C O M P U T E R W I LLL L S H O W Y O U T H E
maximum dive dep depths ths that they are able to calcula calculate te they show show your last last dive or series of dives. dives. Other com puters will scroll only if put in Planning Plan ning mode. Read your dive compute computer’s r’s manual manual to leam how to make make your computer computer scroll.
Dive Mode When a computer computer is in dive mode, it will w ill display data such as your curren currentt depth, maximum depth, water temperature, actua actuall dive time, and the time you have left at your current current depth (figu (figure re 5-22). Some Some comput comput erswill ill also show show a graphic representation representation of the the nitro nitro gen gen in your body body or in various theoretical tissue tissues. s. An air-integrated computer will ill showthe air air pressure ssure in your cylinder. It might also also indicate how much time you have left left at your current current depth based on your air air con sumption (figure (figure 5-23 5-23). ). Some dive com computers puters will ill com pare your remaining air time with your remaining dive time and display whichever is the shorter, shorter, limi limitin ting g factor. As your bottom time time lessens and you approach
Chapter 5- Decompression, Dive Tables, and Dive Computers
n c O T U u I III Q
0
I M
l”
C
is i II i u C
e c o m
IJ o c I II o
p r e s s i o n ,
o CCN U L Cl I cvrccncn C
a
L
l
C
u
C
u
D i v e
_ F IGI G U R E 5 2 4 . A L L D I V E C O M P U T E R S W I LLL L G IVI V E Y O U A W A R N I N G S IGI G N A L W H E N Y O U E X C E E D T H E A S C E N T R A T E.E .
decompression status, some computers give you a visual visual warning warning message such as “GO UP.” When this occurs, you must must begin your ascent immediately, immediately, but but at the proper rate. Most computers require require that that you use an extremely slow ascent rate. Some models have different different ascent rates for different depth ranges. ranges. All dive computers computers give a warning signal signal when you exceed the ascent ascent rate (fig (fig ure 5-24). Some computers warn you with a flashing flashing screen stating something something simila similarr to “SLOW” or will warn you with a flashing flashing red light. Other Other mode models ls warn with with a beep or a synthesized voice. No matter what the signal, signal, you must slow dow down n or possibly stop top your ascent unt untilil your computer tells you to ascend. end. Any time you violate violate your computer’s computer’s ascent ascent rate, you increase your risk of DCS. DCS. Always monitor your computer computer careful carefully ly during during ascent. If you are ever foolish enough to exce exceed your com puter’s maximum depth depth range, range, your computer w wililll warn you with with a message such as “OUT OF RANGE” (figure 5-25). If this occurs, you must must begin begin your ascent imme diately. Your computer computerwill give you the information information
FIGURE 5-25. YOU SHO ULD NEVER SEE THIS WARN ING ON YOUR COM P U T E R . IF Y O U D O , B E G I N Y O U R A S C B V T I M M E D I A T E L Y A N D F O L L O W Y O U R C O M P U T E R 'S I N S T R U C T I O N S .
you need to complete your your decompression and ascent. The computer might also prevent you from using using the computer for 24 hours. You should plan yo your ur dives and then dive your your pla plan n so that you never see a message such as “OUT OF RANGE.”
T a b l e s , a n d D i v e C o m p u t e r s
Decompression You should never see the ceiling ceiling display. display. When your dive computer displays a ceiling, it it means that you have an obligati obligation on to decompress. press. The ceilin ceiling g depth is the depth of your firs firstt decompression decompression stop. You must not ascend ascend above above the depth of that ceilin ceiling. g. You can be 0.3 0.3 or 0.6 meters (1 or or 2fee 2feet) t) deeper, but you must not be shallower. If you require more than one decom decompression pression stop, your computer computer will display another ceiling at a shallow er depth depth than the first first stop. You must complete complete this stop, stop, as well well as any others, unti untill your computer displays a zero zero ceiling ceiling or no ceiling ceiling at all. all.
145
NAU I Scuba S cuba D i ver
P l a n n i n g R e p e t itit ivi v e D i v e s During your surface interval, your computer computerwill give you credit for offg offgassin assing. If you monitor your dis play as it is scrolling, scrolling, you wil willl see see that the maximum time allowed allowed at at any depth increases as you stay out of the water. A surface surface interval interval of at least one hour is still recommend recommended ed even even if if you are using using a computer. When you are are rested and ready to do a repetiti repetitive ve dive, look look for the depth of your planned planned dive as the com puter is scrollin scrolling g and see how long the the computer computer will will allow allow you to stay at tthat hat depth.
Sale to Fly Indicators
F IGI G U R E 5 2 8 . A D IVI V E C O M P U T E R W I LLL L T E L L Y O U H O W M A N Y H O U R S Y O U M U S T W A ITI T B E F O R E Y O U C A N F L Y A F T E R D I V I N G .
Most computers will will tell tell you when it is safe to to fly based on their mathemat mathematica icall model. model. The computer might show an icon of an airp airplane lane or the words words “TIME TO FLY” with hours and minutes minutes listed besid beside e it (figure 5-26 5-26). The computer is tellin telling g you how long you must wait wait before it is safe to fly. When you no longer see an airpla airplane ne or the words words “TIME TO FLY,” it is safe to fly. NAUI and most most medical diving diving authorities authorities recom mend that you be conservative when flying flying after after diving, especially if if you have been been on on a multiday multiday diving trip. trip. You should plan y your our trip trip so that you have at least 24 hours on the surface surface before you need to fly. fly.
t o g g i n g Y o u r D i v e s
F IGI G U R E 5 2 7 . T H E LO L O G M O D E S H O W S Y O U T H E INI N F O R M A T I O N F R O M Y O U R P R E V IOI O O S D I V E S .
146
Even if you use a computer, computer, you sti stillll need to log your dives. Some computers computers will ill allo allow w you to download the informa informatio tion n so you can keep your dive log on your personal computer. computer. Others only only hold a few dives in their their memory soyou should get in the habit habit of transferr transferring ing the informat information ion to your paper logbook once per day. Log mode On most computers, you can c ca all up the Log mode manu manual ally ly by pressing a series series of buttons buttons or contacts on the computer (figure (figure 5-27). 27). The contacts usually usually require that that your fingers are moist and you must touch multip multiple le contacts at one time to complete complete an electric electric Log mode contact. Once Once you are in Log mode,, the computer wi willll showyou the stored div dives, es, starti starting ng with with your your mo most st recent recent dive and moving backward through the stored dives dives..
Chap ter 5-5- De com pression, pression, D i ve T ell el l ies, end Dive Co m puters
Dive Computer Rules You must must obey obey the the following following rules rules when using a dive computer: • Abuddy team canno cannott share one computer; each diver must have their their own computer. computer. A dive computer used by one diver diver canno cannott be usedby another diver on a subsequen subsequent dive unti untill the time required by the computer for complete offgassing has expired. • Read your computer manual manual car carefu efully lly and use the comp computer uter in compliance with the manufac turer’s turer’s instructions. instructions. Completing a Dive Compu Computer ter Specialty Specialty course is recommended mended. • If your dive compute computerr fails at any time during your your dive, you must end the dive and and ascend to the surface at the ascent rate required required by your computer’s failu failure re instructi instructions. ons. Do not forget to perform a 3-minute 3-minute precautiona precautionary ry decompression stop before surfacing. • If If you have been diving diving on tables and want to start diving diving with a computer, computer, you must wait 24 hours after your last dive before using a computer. computer. • If your your computer must be turned on manuall manually, y, do not turn it off u unti ntill it it indicates that offgassing offgassing is complete. • Use the ascent rate specified specified for your your make and model of dive computer. Most computers specify ascent rates that are slower than those those for dive tables. • Athree to five minute preca precautiona utionary ry decompres sion stop at 5meters 5meters (15 feet) feet) is recommended for all all dives made with a dive computer, computer, even if the computer computer does not display display a ceili ceiling. ng. • Plan Plan repetitive dives deep to progressively progressively shal shal lower. • Plan Plan multile multilevel vel dives to start at the deepe deepest depth depth, followed by progressively shallowe shallowerr depths. • Do not make repetitive repetitive dives in in one day to depths depths greater than 30meters (100 feet). feet).
V e r i f y W h a t V o u H a v e L e a r n e d Review the followin following g questions about dive computers: 24. A ceilin ceiling g display display indicates indicates the depth to which which you can . 25. The maximum maximum recommended depth for a repet repet itive dive using a dive co compute mputer is is meters ( feet). 26. A computer computer goes through through an when when you first turn turn it on. 27. occurs when a computer reads reads out each allowabl allowable e depth and maximum dive time when you are on the surface. 28. If you ascend above the ceili ceiling ng indica indicated ted on your dive computer, you risk _______________
________
_______
_______________
_______________
29. Two ways a computer computer can warn warn you that you have exceeded your your ascent rate rate are and and ______________
CONCLUSION By working working with the NAUI Dive Tables and the NAUI Dive Time Calculator, Calculator, you will will soon feel comfortable with their use. Your instructorwill help you with any difficulties you might have. Remember that you must plan and record your dives to help prevent DCS. Computer puter diving is easier than diving with manual calculati calculations, ons, but you must remember how to useyour dive tables in case a computer is not availa available. ble. Dive computers are in common use, and there will will probably be a time when when divers no longer usedive tables. However, to be a versatile, versatile, aswell well as knowledgeable diver, you must understand the dive tables and the principl principles es of dive computers. Be sure to read the manual manual for your dive dive computer computer so you are completely fam familiar iliar with its operation. Be sure to take the manual manual with you on your dive trips for handy reference. Computers and dive tables will will not eliminate eliminate the risk of DCS. Always make a precauti precautionar onary y decompression stop at the end ofevery dive and be conservative in in the useof your dive computer or dive tables.
CHAPTER
p j jg
NA UI Scuba Sc uba D i ver
L EA R N IN G G O A L S n i d r o c e R d n a g n i n n a l P e v i D
In this chapter you will: • Learn about the steps to long range range and and short range planning. • Be introduced introduced to the steps to follow follow to safely safely con duct your dive. • Learn why it is important to plan your your dive and dive your plan. • Be introduced to the importance of recording recording each dive dive you do. To further further reduce the risks in diving, diving, it it is essential that you plan and prepare your dives in advance. Also, Also, the best way for you to get the most enjoyment enjoyment out of ,plann ,pla nning ing diving diving is to plan plan your dives. dives. For our purposes is all all of the arrangements arrangements you make for a dive, from the time you decide decide to to go diving unt untilil your your planned dives are complete. Planning is divided into sections: • Long Long range planning. planning. • Short rang range e planning. • Preparing to dive dive.. • Conducting Conducting your dive. • Post-dive review. You need to know the step steps of planni planning ng so you can can enjoy the best best kind of dive. dive. Plan Planni ning ng ensures ensures you have all all the equipment equipment you need need in goodworking order, that you know what to expect expect at the dive site, and helps you avoid any last minute rush. In some cases, being able to go divin diving g is possible only only because you have made reservations in advance. When you, your equipment, equipment, and your buddy buddy are well prepared for a dive, you will will have the best possible possible chance of having having a pleasurable pleasurable experience, which is the goal of recreationa recreationall diving.
before a dive to start plannin planning, g, it may be be too late to pull everything everything together to have a successful dive. Your first first step is to plan plan the objective of of your dive. For example, you might want to practice your naviga tion skills skills or try out a new new underwate underwaterr camera. camera. Your objective might might also be to see a new new area of of the world world and the diving diving it it has to offer. offer. Your second step is to select select your locati location. on. Your locati location on could could be anywhere in the world, and take from a few minutes to a number of days days to reach. You should m also discus discuss s an alternate alternate location location in case case conditions are unacceptable unacceptable at your primary location. location. Rememb Remember er to to investigate whether the location location is is a marine preserve, whether boat traffic traffic or fishermen are are present, present, and so on. on. If the dive dive site is unfam unfamilia iliarr to you, you, you must must research it. Books are availab available le that provide informatio information n on popular locations, locations, but you should also find a contact person person in the area to obtain obtain loca locall knowledge knowledge about about the proposed site. Sources includ include e dive resorts, resorts, dive stores, stores, dive clubs,dive instructors instructors and dive masters masters.. The more you can lear learn n in in advance, the better better prepared you will will be.
LONG RANGE PLANNING Your long-range planni planning ng begins many months ahead ahead of a major dive trip. For a day of diving at a local local site, your long-range plannin planning g also begins well before your dive. dive. If you wait until until the night or even even the week week
150
F IGI G U R E 6 - 1 . P R E D IVI V E O B S E R V A T IOIO N S A R E A N I M P O R T A N T C O M P O N E N T O F D IVI V E P L A N N I N G .
Chapter 6- Dive Planning and Recording
F IGI G U R E 8 -2- 2 . O N E O F T H E B E S T W A Y S T O M A I N T A INI N F ITI T N E S S FOR DIVING IS TO SWIM REGULARLY WITH MASK, SNORKEL, AND FINS.
E 3
If possible, you should also look at the dive site in advance (figure 6-1). This will will show you a great great deal about the site’s accessibilit accessibility, y, parking, parking, fees, conditions, facilit facilities ies,, and entry and and exit points. You might also find divers who can point things things out and exp explain lain the bes bestt procedures for the location. location. Do not forget forget to investigate the emergency services in the area. Also, remember that that conditions conditions on your dive day can be radically radically different. different. Your third third step is to determine determine the date date and time of your dive or dive dive trip. Be aware aware of any conflicting conflicting acti activi vi ties that might affect the date date you want to dive, incl includ ud ing plans plans you have made for the night night before the dive. It is unwise and unsafe to dive the morning af after ter attend ing a late night night party party you had forgotten forgotten was was planned when you scheduled your your dive. You should not consume alcohol alcohol within within 12 hours of a planned dive. It is even even better better if you do do not consume alcohol within within 24 hours hours of a planned dive. You must not be hung over and you you must be well rested. If you are diving diving from shore, shore, the time of day for your dive is also a consideration. Local Local winds might be light light in the morning and strong strong in the afternoon, or vice versa. You might want to schedule schedule your dive during high tide, becau because se visibilit visibility y is usually usually better better at this time. time. Your fourth step is to make travel arrangements. arrangements. This could be anything anything from deciding whether you or your buddywill drive to the the dive site to making airline airline,, hotel, and boat reservations. reservations. Your fifth fifth step step is to determine your equipment needs. For example, if if the water temperature temperature is different
from the water temperature where where you normall normally y dive, you might need to obtain a different type of diving diving suit. Different diving suits will will change the the amount of weight weight you need to wear to ensure th that at you have have good buoyancy control during during your dive. Check to see see if your your buoyancy compensator or regu lator lator need needs s annual annual servicing. servicing. If so, so, make sure you have any item in in need of service checked checked at your local local NAUI Pro Center well in advance of the trip. Your Your sixth sixth step is to determine whether whether you need to take a NAUI Refresher Scuba Scuba Experience before your trip. If you have not not been diving in six months or more, ore, a refresher refresher is a good way to brush up on your your knowledge and water skills. Check Check with your local local NAUI Pro Center Center or the instructor who who trained you on the availa availabi bility lity of a NAUI Refresher Scuba Experience. You must also be fit fit to dive. Regula Regularr exercise exercise helps to develop stamina. One of the best bestways to maintai maintain n fitness for divin diving g is to swim regularly regularly with mask, mask, snorkel, and fins (figure (figure 6-2). 6-2). It is vital vital to prep prepare are a “to “ to-do” list for arranging arranging your your dive. Keep it handy so you can add to it as thoughts occur. NAUI Pro Centers Centers have checklists available available on a slate if if you prefer not to make your own. Use Use this list list to develop a checklist that wil willl be helpful when planni planning ng future future dives and dive trips. Do not rely rely onyour your memory. SeeAppendix C for a sample checklist. checklist.
V e r i f y W h a t Y o u H a v e L e a r n e d Review the followin following g questions about long-range long-range planning: 1. The six steps to long range plannin planning g are: a. b. c. d. e. f. 2. You should start planning a major dive trip in advance of the the trip. 3. You should start planning planning a day of diving at a local site in advance of the dive. ________________________________
________________________________
________________________________
________________________________
________________________________
________________________________
__________________
__________________
NAUI Scuba Diver
S H O R T -R- R A N G E P L A N N I N G Short-range Short-range plann planning ing starts about a week before before your dive. You need to inventory your gear and inspe inspect it to be sure sure it it is in good condition and ready for use.
M y W h a t Yo u Ha ve Le arn ed Review the follo following wing questions questions about shortshort-range range planning: 4. Some Some typical typical item items s you might need to buy
Make any repairs you are qualified qualified to make, such as
for your trip include
replacing replacing cracked straps on your fins or mask. mask. Avoid waiting waiting until until the last minute to buy items you will ill need need for your trip. Determine Determine what you need, write
and and
it down, and get it in advance. Typical Typical items items include include air air
__________________
__________________
,
.
5. You should leave a copy copy of your plans with with some one at home so
fills fills for your scuba cylinders, film, film, sunscre sunscreen, en, seasick seasick ness medication, fishin fishing g licenses, light light sticks for night
6. Check the
diving, and defog defogger for your mask. mask. Your list list should
□
also include include spare parts for your divin diving g equipment. equipment.
and
Having an extra mask strap strap or tank valve valve O-ring can
trip.
a few days before your
save time and frustrati frustration on at the dive site. As you pack your gear, check it against a list list to ensure you have everything everything you need. One or two days before your trip trip check check the weather
m
trends, water conditions, conditions, tides, and the long-range weather forecast. Your NAUI instructor instructor will will advise you
Once you have completed all all your long- and short-
about about available sources sources of this type type of information. If
range preparations preparations,, it should be easy to to complete complete the
you know in advance that that the weather mig might ht be bad on
last-minute details of preparing preparing for a dive. The day or evening before before your scheduled scheduled dive, gather all all your your
the day you plan plan to dive, you might might be able to avoid wasting a trip. Always be sure to leave a copy of your plans with
equipment and personal artic articles les in one place.
someone. Be sure sure to include the following in your plans:
gear and one for personal items. Your personal items
Pack Pack your gear into two bags: bags: one for your dive
• Your destinat destination ion and dive sites.
include include your towel, extra dry clothing clothing such as a jacket,
• Contact telephone telephone number.
snacks, a camera, camera, and so on.
• The date and time you expect to to arrive arrive back home. This way, assistance can can be summoned to look for you if you you are unusual unusually ly late in returning returning home. home. Do not forget to notify the person holding the plans if if you are
152
PREPARING TO DIVE
Pack Pack your dive gear in reverse reverse order of its use. use. Put your fins, mask (in (in a crush-proof -proof box), and snorkel snorkel on the bottom, bottom, and your your buoyancy buoyancy compensator compensator and regu
ED
lator lator on top, as those those are usuall usually y assembled assembled on your cylinder first. first. Do not packyour weight belt with your
going going to be be intentiona intentionally lly late. Plannin Planning g a dive dive might seem seem like a lot of trouble, but it it becomes easy and fun to do after after a few times.
dive gear. The weights weights will ill make your bag too heavy
You You will will enjoy talking diving diving with your bud buddy dy and and others from whom you obtain informa information. tion. You will ill
Be sure to get get a good night’s night’s rest and avoid drink drink ing alcohol alcohol at least 12 hours befor before e diving. It is even even
feel better from being prepared. prepared. To be comfortable comfortable with your dive, you must arrive arrive at at the dive site site feeling that
better better if you can avoid drinking alcohol for 24 hours hours.. You must be well rested rested, in in good good health, and have a
you have done everything everything possible possible to ensure success. success.
good feeling feeling about the dive.
and could damage it, or other items. The easiest easiest way to carry carry your belt is to wear it.
ED
Chapter G- Dive Planning and Recording
V e r i l y W h a t Y o u D a v e L e a r n e d Review the followin following g questions questions about preparing to dive: 7. One item that that should should go towards the bottom of your dive bag is . 8. One item that that should go towards the top of your dive bag is . 9. You You should abstain from drinking drinking alcoho alcoholl at least hours before diving. _______________________
includ including ing when to change course, when to begin begin the return return leg, and when to surface. Partners Partners can always make suggestions, but both must agree that that most deci sions be made bythe dive leader. The leader leader does not nec essarily essarily need to be the most experienced or qual qualifi ified ed mem ber of the team. The personwho is most fam familia iliarr with the area should lead lead on the first dive, and the other buddy buddy can
______________________
lead on subsequent dives, or the pair pair can alternate.
________
E m e r g e n c y P la n You must discuss discuss contingency contingency plans, plans, emergency emergency procedures, and accident accident management. management. Agree Agree on on what
C O N D U C T IN I N G Y O U R D IVI V E When you and your buddy buddy arrive arrive at your selected site, you must agree on howyou wil willl conduct your dive before before you enter the the water. The acronym, SEABAG, SEABAG, is an easy way to remem remember the series of steps steps that that you follo follow w to plan a dive and check each other’s other’s equipment. equipment. SEABAG stands for: • Site survey • Emergency plan plan and information information • Activity • Buoyancy • Air Air • Gear and go See Chapter 3 for the steps steps for buoyancy, buoyancy, air, air, and gear and go. go. The steps for site survey, emergency, and activity activity are covered covered in this section. A checklist checklist for the steps is included included in Appendix C.
m
S ite S u r v e y J
Before you even suit up, evaluate the conditions at the site to determine determine if if they are acceptable for your planned activity. If the conditions are are bad, bad, travel to an alternate locat location ion or do not dive. dive. Never Never be afraid afraid to say say that you do not feel good good about diving in poor condi condi tions. The purpose of a dive is enjoyment, a and nd there is no fun if if the conditions are bad. Once you decideyou can can dive, dive, you must determine I which buddywill ill be the leader of the team. This person is in charge of the the decision-making during the dive,
to do if one of you runs out of air air under water. Agree Agree on what to do do if you get separated under water. water. One suggested gestedplan plan for a lost lost buddy is fully fully explained explained in in Chapter 3 - Buddy System. System. Agree on how to summon help if if you need it. Discuss Discuss the steps teps you wil willl take if an accident accident or emer gency gency should should occur. Make sure you have the informa informa tion about about local local emergency emergency contacts contacts available available and that you know the location location of the nearest working telephone. Take some time to be prepared for emergencies, because little little time will will be available if one occurs. occurs. Acciden Accidents ts can happen any time you are diving. You must must be prepared prepared for them.
A c t i v i t y There are many things you can do while while diving, diving, but you should select only one activ activity ity as the purpose purpose of any one planned dive (figur (figure e 6-3). It is unwise, and can be be unsafe, unsafe, to try and and combine combine activities on a single dive. dive. If you try to spear fish and take photographs photographs on one dive, you are not not likely likely to do either very very well. It also helps if you and your budd buddy y have have simila similarr interests. interests. You must agree agree on on the activi activity ty and objective of your dive. Discuss what you want to do, howyou will will accomplish the activity, and any special signals you will ill be using. You must also review your standard hand signals. Communicate as much as possible before the the dive, because because it is more diffi difficu cult lt after you are under water.
NAUI Scuba Diver
You must must decide on your entry and exit points and your dive pattern. You must both understand the course course you will follow and agree agree on it (figure (figure 6-4). 6-4). Set your limits limits for depth depth,, time, and air air supply. supply. Decide Decide on your depth and time limits limits according to your dive tables or dive dive computer. computer. Decide at what point point you will turn around and start toward toward your exit point. point.
V e r i l y W h a t Y o u H a v e L e a r n e d Review the the following following questions questions about conducting your dive: 10. SEA stands for , and _____________________
______________
11. The first first decisi decision on you should should make when you reach your dive site is 12. The dive leader leader is responsible responsible for and 13. You should wait wait at at the surface for for your buddy buddy for fo r minutes minutes befor before e signaling signaling for help. help. 14. You should verify verify that the telephone close closest st to your dive site is before you start your dive. 15. Your activity activity plannin planning g should include include setting your limits for , and and .
DIVING YOUR PLAN You must carry out the plan plan you have made for your dive. You must not abandon the dive plan midway through the dive. dive. If something occurs occurs that must must cause cause you to deviate from your plan, surface or even even exit long enough to make new new plans, rather than than to try and change them under water. You and your your dive buddy must must be be in accord when you dive. This is diffi difficu cult lt to do evenwhen you agree on your plan plan before the dive. If one team membe memberr varies from from the plan, confusion results. results. Plan Plan ahead when you dive. dive. Remind one another of your depth depth and time time limits, limits, and follow your plan m throughout the dive. Accomplishing Accomplishing what you set out to do and ending a dive exactly exactly where you planned is very rewarding. Consider dive plannin planning g and the abili ability ty to execut execute e your plan as a challenge (figure (figure 6-5). 6-5). This will will add toyour enjoyment of the dive and reduce any risks. When you are prepared for a dive, many many benefits benefits result and these benefits are worth the time you take to properly plan plan and prepare. As you work with others to coordinate your di dive, ve, that that work will ill become first easy, then fun. fun. You will find yourself enjoying the the prepara prepara tions involved involved for the dive as well as the dive itself.
_____________
__________________
_______________
V e r i l y W h a l Y o u D a v e L e a r n e d Review the following questions about diving diving your plan: 16. If If one team member varies varies from from the predeter mined dive plan, results. 17. Dive planning planning and the abili ability ty to execute your plan with with the the desired results is a .when you and is achieve your goal. _________________
________________
____________________
CONTINGENCY PLANNING
F IGI G U R E 6 - 3 . W H E N Y O U O I V E , C O N C E N T R A T E O N O N L Y O N E A C T I V ITIT Y . F O R E X A M P L E , U N D E R W A T E R P H O T O G R A P H Y T A K ESE S GREAT CONCENTR ATION TO DO W ELL.
Contingency Contingency planning is an important important part of dive dive plannin planning. g. For each step of your plan, plan, you need to to have have a contingency plan. When you choose your site, also choose choose an alternate alternate site or an alternate activ activity ity for the day in case case conditions are not right for diving.
Chapter 6- Dive Planning and Recording
When you are checking your equipment and pack ing for your dive, consider taking extra gear along along if you have it. If you have a grou group p going on on a trip, the mem bers of the trip might be able to bring alon along g an extra extra reg ulator, ulator, buoyancy com compens pensator, ator, fins, fins, mask, mask, and snorkel among them. It is much easier easier to switch to another piece of gear gear than to fix a piece of gear in the field. When you are planning planning the direction direction of your dive, be sure to to consider an alternate alternate route or alternate alternate exit exit point to be used used if conditions conditions change whi while le you are on your dive. Be sure sure to consider what you will will do if your buddy has a problem problem under water.
HI
F IGI G U R E 6 -4- 4 . A S A T E A M , Y O U M U S T 0 E C I 0 E A N D A G R E E O N Y O U R
V e r i f y W b s t Y o u H a v e L e a r n e d
ENTRY AND EXIT POINTS ANO YOUR OIVE PATTERN.
Review the the following following questions questions about contingency planning: 18. When you choose your site, you shoul should d also choose an or an ______________________
19. When you plan plan the route of your your dive, you should also consider
RECORDING YOUR DIVE
H I
After each dive, you should record informatio information n from your dive in your logbook (figure (figure 6-6). 6-6). There are space spaces on your logbook pages in whic which h you record: • The number of your dive. • The date. • The water visibi visibilit lity. y. • Your starting air air pressure pressure.. • Your ending air air pressure. • Your Your deepest depth. On the right right side of the NAUI Logbook pages are three boxes for recordi recording ng your divi diving ng hours. Use these to keep a running running total total of your dive time. The number in the Start box is the same as the number number in the Total box box from your previous dive. The number in the the Dive Time box is the number of minutes from your current current dive. Addthe number of minutes from your current current dive
F IGI G U R E 6 - 5 . A L W A Y S P L A N Y O U R O I V E A N D T H E N D I V E Y O U R P L A N .
to your total total from the Start Start box and put the new total in the Total Total box. Underneath Underneath the boxes are lines to record: • The The location location of your dive. dive. • The name of your buddy. • Remarks about about the dive. Your remarks remarks about the dive dive can include informa tion such as the diving suit suit and the amount of weight you were were wearing, the cylinder cylinder size, whether you liked the site, what what you saw, and so on.
NAU I Scuba Sc uba D i ver
The bottom of the page has a blan blank k area area for for you to recordyour dive profile iinform nformation ation from your NAUI NAUI Dive Plann Planning ing Worksheet on the back of your NAUI Dive Tables. The bottom also has space for an instru instructo ctorr to sign if the dive was a trainin training g dive. On a dive trip, trip, many divers ask the dive operator to stamp or sign this area. area. Get into the good habit habit of recording the inform informa a
□
tion from your dives at the end end of each diving diving day day or after each dive. ive. The information w will ill be fresh in your mind and easy to record. record. If you wait until until the end of a trip to record the information, information, there is a good good chance you will ill forget some important information information..
V e r i l y W h a t Y o u H a v e L e a r n e d
F IGI G U R E 8 - 8 . Y O U M U S T R E C D R O Y O U R O I V ES ES I N Y O U R L O G B O O K .
Review the followi following ng questions about recording your dive: 20. List List three pieces of informatio information n you record in the boxes at the top of each page of your your logbook:
21. In In the NAUI Logbook, the purpose of the Hours Hours box is so you can ca n . 22. Remarks Remarks about your dive can include include infor informa ma _____________________
tion such as
______________________
156
and
J l i v e P l a n n i n g a n d R e c n r d i n g
157
NA UI Scuba Sc uba D i ver
LEARNING GOALS In this chapte chapterr you you will: will: • Learn the general method method for resolving resolving problems problems under water. • Be introduced to situations situations that that can occur under water and how you can prevent them them from occur occur ring ring or resolve resolve them if you do encounter them. • Learn how to assist another diver if if they are hav ing a problem. • Be introduc introduced ed to the steps you need to take to res cue another diver at the surface and underwater. underwater. • Learn about first aid for aquatic injuries. injuries. • Be introduced to the the importance of of safe diving diving practices.
go
Diving Diving always entails entails some degree egree of risk. Even if if you do do everything everything right, there is still still a slight but real possibility that you might be injured, while under water. water. Fortunately, Fortunately, diving diving accidents are rare, and you can avoid them by solving small small problems early - before before they become big problems. problems.
DIVING SITUATIONS Some situations can occur as you dive dive that will will bother you. You can deal with most of these situations situations if you stop to analyze and cope with them calmly. calmly. As long as you have air air to breathe, breathe, you can deal with with almost anything. Keep this thought in mind, and you will ill soon view everyday everyday dive problems as the the minor minor annoyance they are.
m
160
There are three stepsto solving solving a problem unde underr water: 1. Stop your activity. activity. 2. Get firm firm control control of yourself and analyze analyze the situation. 3. Take action action based on your analysis. analysis. Remembering and following following these three step steps will will help you you deal with any situation in a calm manner manner and can prevent a situat situation ion from getting worse worse..
Water conducts conducts heat quite quite efficiently efficiently and it can abso absorb rb a great deal deal of heat with very llittl ittle e change in its own temperature. When you are imm immersed ersed in water without proper thermal protection, heat is rapidly rapidly drawn from your body. This process is called called conduction. You also lose heat under water every time you take a breath and exhale, as your body warms the air air you inhale. inhale. You can lose lose a significan significantt amount of your body body heat this way. This effect increases with depth, depth, because because the density density of the air you are breathing breathing increases with increased pressure. pressure. The temperature temperature of the the water can also drop as you dive deeper. The deeper you dive, dive, the greater greater the pressure that works to compress your wetsuit. The more your wetsuit compresse presses, s, the less insula insulatio tion n you have. This is is unfor tunate, because because as you dive deep deeper, the water usuall usually y gets colder. This is another another good reason to limit limit your diving diving to shallower shallower depths depths.. Diving Diving is more more fun, and safer, when you are warm. If your your body loses loses enough enough heat, you can develop a medical condition known as hypothermia. In Greek, hypo means low and therm means heat or temperature. The symptoms symptoms of heat loss include: include: • Loss of muscle strength. • Muscle cramps. • Numbness mbness in your arms and legs or inab inabilility ity to use your fingers or hands. • Increased breathing rate with no increase in your activity. • Shivering. • Fatigue. • Los Loss s of ability ability to think clearly. clearly. If you ignore ignore the symptom symptoms, and your your body body contin contin ues to lose lose heat, you will will develop a serious medical emergency. Heart irregul irregulari aritie ties, s, unconsciousness, and even death can occur. If you become cold while diving, diving, you must rewarm yourself. End your dive and get out of the water. Get into warm, dry clot clothing hing as soon soon as as possible possible.. Layers of clothing clothing or blankets also help to trap warmth near your body body. Warm drinks will will help, but avoid any with caf feine or alcohol. alcohol. Awarm, not hot, hot, bath might also h help. elp.
Chapter 7- Problem Solving
Hot baths are not not recommended after deep dives, because they might increase the possibility possibility of decom pression pression sickness sickness (DCS (DCS)) or cause other problems problems as cold blood diverts from your extremities. Hot baths baths for severe cases of heat loss must be avoided. Medica Medicall attentio attention n is necessary. There are many many defenses against against heat heat loss in the water. Some of these hese are natura natural,l, but some require deliberate action action on your part. Your body’s first first defens defense is to reduc reduce e the circ circula ulatio tion n of blood to to your arms and legs. This conserves conserves heat in the core of your body where where the vital vital organs are locate located. d. Once Once your core tempera ture (the (the intern internal al temperature of your body) lowers suf ficiently, you begin to shiver. Shivering Shivering indicates indicates chilli chilling ng.. Normally, the purpo purpose of shivering shivering is to produce produce heat, but shive shivering ring when you are under water water cannot help wit with h your heat loss and might make it worse. rse. You must must take shivering as a sig nal to end end your diving activities until until you recover recover.. If you eat a well-balanced meal at least two hours before diving, your body will ill generate generate heat and your body body will will have fuel to dive. dive. Your activity activity level while while you dive also also affects how much heat heat your body generates. generates. Kicking Kicking at a moderate moderate pace pace will will help generate som some heat. Just Just remember ember that heavy exercise is diff difficu icult lt under water water as it requires you to use large large amounts of air that quickly depletes your air supply. Your best defense in cold water is to wear the right right amount of insulation insulation for your need needs. If you get get cold cold while diving, diving, you need need to wear more insulation. insulation. If you are already wearing a full full wetsuit with hood, boots, and gloves and are cold, you might need to switch to a dry suit suit to keep warm. If you are wearing a dry suit and are still still cold, you might need more more insulat insulation ion or a different type of underwear underwear beneath beneath your suit. It is is especially important to cover cover your high heat loss areas, areas, includin including g your head, head, hands, hands, torso torso,, groin, and neck. With the proper insulatio insulation, n, you can staywarm in almost any diving environment. You must leam leam to recognize hea heatt loss as a poten tial tially ly serious diving diving problem. You should stop top diving diving when you becom become chilled chilled.. Rewarm yourself completely before you dive again. again. If you wear the right right amount of insulati insulation, on, dive wisely, recognize the symptoms of
heat loss, and res respon pond appropriately, appropriately, you can can avoid avoid heat loss problems.
Most Most people people tend to think think about problems problems associat associat edwith staying warm in cold water rather than with overheating. overheating. Problems with overheating usually occur on the surface as you are preparing preparing to dive, but can occur while diving in in warmer waters waters.. A diving diving suit suit protects you against against heat loss in the water, and it also does sowhen you are on the surface. This can lead to serious problems due to to overheating before, before, during, during, and after the dive. dive. Your body’s body’s first reaction to overheating (hyperther mia ) is to perspire. This This can lower your body temperature as the moisture evaporates from your skin. Unfortunatel Unfortunately, y, this does not work when when you are covered head to toe by a dry suit, wetsuit, wetsuit, or other insulati insulating ng garments. ents. If you overheat and do not act to cool yo your ur body, body, you will experience some or all of the following symptoms of heat heat exhaustion: exhaustion: • Pale, clammy skin. • A feeling feeling of weakne weakness and fatigue. • Headache. Headache. • Nausea and possibly vomiting. You should should take action immediately to lower your body body temperature. If you are in a wetsuit, wetsuit, get into the water for a quick cool-off dip. If you cannot do this, get out of your exposure suit suit and get wet wet to start cooling cooling down. If you are not nauseous, you can drink drink cool water to rehydrate your body. body. Be sure to stay out of the sun and rest unti untill the symptoms symptoms go away. If you do not take these these actions, and your body temperature continues to increase, your your self-cooling respon responseswill ill shut down. This leads to an extremely extremely serious, life-threatenin life-threatening g condition condition known as heat stroke. The skin of a heat stroke victim victim is dry and hot to th the e touch. You must get get medical medical assistance immediately. To prevent overheating, pace yoursel yourselff when don don ning ning your exposure exposure suit. Be sure to stay out of the sun. sun. If necessary, get the suit wet and keep it wet while while you are donning the sui suitt and then enter tthe he water quickly quickly after you you have finished suiting suiting up. up.
o b l e m
S o l v i n g
m
161
NAU I Scuba D i ver
G O
Cold, Cold, exertion, exertion, incorrect kicking kicking with fins, restricted restricted circul circulati ation on,, or some combinatio combination n of these hese factors can lead to cramps, which which usuall usually y occur in the legs. legs. The best way to deal with this problem problem is to prevent cramps before they occur. occur. Avoid becoming becoming chilled chilled or exhausted, exhausted, and avoid wearing protective clothing that is too tight. IT JH If you experience rience a cramp, cramp, stretch stretch the cramped cramped muscle and massag massage e it (figur (figure e 7-1). For cramps in your calf calf or foot, foot, pull pull on the the tip of your fin fin gently as you straighten your leg. This stretches stretches the muscles that are H ± ii respons responsible ible for the the cramp. cramp. Stretch your muscle muscle gently gently or you can injur injure e the muscle or tendons. tendons. Once you have relieved a cramp, rest and recover, recover, and then continue your dive at a slower pace. pace. You can also use a different kick kick to help keep a leg cramp from recurring. recurring. F IGI G U R E 7 2 . R E M A I N C A L M I F Y O U B E C O M E E N T A N G L E D , D E T E R M INE WHERE YOU ARE CAUGHT, AND W ORK SLOWLY A N D D E L I B E R A T E L Y T O F R E E Y O U R S E L F
F IGI G U R E 7 - 1 . Y O U C A N R E L I E V E A C R A M P B Y G E N T L Y S T R E T C H I N G T H E A F F EC EC T E D M U S C L E .
162
Entanglements typically typically occur with underwater underwater plants, fishing line, line, or fish nets nets (figure (figure 7-2). You should have a knife available available soyou can cut yourself free, free, but that is seldom seldom your first first reaction reaction to an entanglement. entanglement. First, First, stop your activ activity ity and get control. control. Second, Second, deter mine where you are caught and what object has caught you. Remain Remain calm. You might be able to free yourself by pull pullin ing g the plant, line, or net clear of you and your gear, gear, or by get get ting your your buddy to help you. Sometimes Sometimes you can reverse reverse your directio direction n to get free. Remember Remember that you have buoyancy control control and the abili ability ty to move up and down down to free yourself. Avoid turning turning around, becaus because e this will will usua usually lly make an entanglement worse. worse. One of the most most likel likely y points of entanglement is your cylinder cylinder valve and the the first stage stage of your regulator. Unfortuna Unfortunately, tely, you cannot cannot see this area, so you should signal signal your dive buddy to help you. If your buddy is not close to you for for some reason, you can can remove your scuba unit, unit, free the entanglement, and put the unit back on.
Chapter 7- Problem Solving
If none of these actions clears clears you of the entangle ment, you might have to use use a knife knife to cut yoursel yourselff free. Use caution and work work slowly and deliberately. Pani Panic c is your worstenemy in this situat situation, ion, not the entanglement.
Disori Disorient entati ation on, not knowing where you are or lite liter r ally ally which which way is up, up, can can occur for several reasons when you dive. Sensory deprivation, deprivation, where you cannot see , anything anything in the water water around you, can occur during during poor visibi visibility lity or night diving. Sensory Sensory deprivation can
cause cause dizzin dizziness ess or vertigo (figur (figure e 7-3). Ear Ear problems, a ruptured eardrum, eardrum, or trouble trouble equalizi equalizing ng when you you descend or ascend, can also cause vertigo vertigo.. To help overcom overcome disorientat disorientation, ion, you must over come the dizziness and then determine whic which h way is up. To overcome dizziness, hold onto a solid solid object object or hug [T l ] yourself yourself unti untill the dizziness dizziness passe passes. Do not close your eyes. To know which which way is up, look look at your bubbles. Air always rises. You should should postp ostpon one e night or limited limited visibi visibility lity div ing until until you acquire acquire confidence through dives dives with good visibility. If you have have an ear problem that might not allow you to equalize your middle ear pressure, you might experience vertigo. Vertigo sometimes occurs during during ascent, when one one ear equalizes more rapidly rapidly than the other. The dizziness will ill pass in a few moments. Do not getexcited if if you do experience vertigo. Problems with disorien disorientatio tation n are rarely rarely severe. vere. Your most likely likely problem is not knowing your position under water rela relativ tive e to where you want to go. go. Develop the ability ability to knowwhere you are through na natur tural al and compass pass navigation navigation and you you are not like likely ly to experience experience the nuisance of disorientation. disorientation.
Equipment Difficulties Equipment Equipment difficulties difficulties include gear that is or becomes improperly adjusted, undone, or lost while while div ing. It also includes gear gear that malfunctions. malfunctions. Any good diver can handle the these se difficulties, difficulties, soyou will will want want to learn learn how how to handle them as well. Your instructor instructor will will
F IGI G U R E 7 - 3 . P R O B L E M S W I T H D I S O R I E N T A T I O N A R E R A R E L Y SERIOUS, BUT IT CAN INVOLVE VERTIGO.
help you deve develop this skill skill by giving you typica typicall equip ment problems to solve as your traini training ng progresses. You can adjust almost almost every piece of equipment while while in the water. If you must make an adjustment, first first thin think k about what you need need to do, then work slowly and deliberately deliberately to make the adjustment. adjustment. If you becom become excited excited and find yourself working hard, stop stopyour activi activi ty, recover, think, and start again slowly. slowly. Working with your gear in the water is good good practice to keep many of your diving skills sharp. You could lose your mask, snorkel, fins, fins, or weight belt under water. Each Each piece of equipme equipment nt is needed for diving, diving, but but you must must be be able to either recover the lost item and continue continue your dive or be able to reach the surface and exit the water without the missing item item.. Practi Practice ce swimming witho without ut items of equipment to to devel devel op the the techniques techniques for handling handling this type type of difficulty. difficulty. Occasionally Occasionally,, the power-inflator power-inflator mechanism on your buoyancy compensator (BC) (BC ) can stick in the open position, which causes the BC to inflate inflate.. If this happens, you must vent the exce excess air air and and disconnect the power-inflator hose hose (figure (figure 7-4). If you do not vent the the
NAU I Scuba Sc uba D i ver
F IGI G U R E 7 - 4 . I F Y O U R P O W E R - ININ F L A T O R M E C H A N I S M S T ICI C K S I N T H E O P E N P O S I T IOI O N , A N D Y O U C A N N O T D I S C O N N E C T ITI T , A S C E N D T O T H E S U R F A C E .
air air immediately, you can experience experience an uncontrolled uncontrolled ascent, ascent, which could lead lead to a lung overexpansion injury injury or DCS. If your disconnected power-inflator hose itself itself continues to free-flow, you should ascend immediatel immediately y at a normal rate, as your air air supply will will be quickly exhausted austed. One way to to slow a buoyant ascent is by flaring flaring.. To flare flare your body, get yourself yourself face up and para paralle llell to the surface. Spread your arms and legs out and away from your body and hold the blades of your fins fins para paralle llell to the surface. Doing this will will create as much surface area and drag as possible to slow your ascent. Regulators Regulators do not usually fai faill in a closed position position in which they they will not deliver any air. Usually, any malfuncti malfunction on causes a free-flow. -flow. If either either does happen, or your regulator regulator second stage floods becaus because e of a leak leak ing exhaust valve, you must must treat the situation situation as an out-of-air situation. situation. Follow Follow the the procedures procedures outlined outlined in Chapter 3 for hand handling ling out-of-air out-of-air problems problems..
Seasickness is an unpleasant unpleasant occurrence tha thatt no one enjoys. Seasickness results when the signals signals from from your inner inner ear ear and the signals from your your eyes eyes to your brain do not match.
If you start start to feel nauseous nauseous while on the boat, boat, do the followin following g to help prevent seasickn seasickness: 1. Avoid eati eating ng greasy foods. 2. Stay Stay out of of the cabin or any enclosed space on the boat. bow 3. Settle yoursel yourselff in a spot midway between the bow stern (back) (front) and stern (back) of the boat boat and betw between een One starboard (right) and po rt (left) and port (left) sides. This is the boat’s midpoint. The boat is most stable stable at its midpoint. 4. Look at the horizon. lee (downwind) If you must must vomit, go to the lee (downwind) side of of the boat to be ill ill. Never use the boat’s boat’shead (bathroom). (bathroom). Many divers who get mild mildly ly seasick find that that they usuall usually y feel better better once once they are under under water. water. You must not dive if you are actively actively vomiting vomiting or extremely nause nause ated, though, because of the the danger of inhal inhalin ing g vomit through your regulator. This can cause you to choke choke and the the vomit can injure injure your your lungs, or cause lung infections. If you know you get seasick and can avoid it by using medication, medication, it it might might be permissible permissible to do so. If you do take medication medication for for seasickness, it must not produce adverse side affects (su (such ch as drowsiness or dizziness) that could put you in danger under water. You must test test the medication for its its effects on on you well in advance advance of your day ofdiving. Be aware that the the effects might be radica radically lly different different when under pressure soyou must be alert alert to the effect of the medication medication under pressure aswell. well. If you wait until the boat is moving to take medication, medication, it it is too late. For best results, you should usuall usually y start taking seasickness seasickness medication the night before before your trip. Follow Follow the dosag dosage instructions of the manufacturer.
It is possib possible le to inhale a little little water when you breathe through a rregulato egulatorr under water and start to choke. choke. You should try to to prevent this from occurring occurring by using the follo following wing steps: 1. Raise Raise your tongue to the roof of your mouth to form a barrier barrier to kee keep p drops drops of water from going through your mouth and into your throat.
Chap ter 7-7- Problem Solving Solving
2. Make Make your first breath after clearing clearing a snorkel or regulator shallow and cautious. cautious. If you must cough, cough, keep the the regulator regulator or snorkel in in your mouth. mouth. Keeping Keeping the mouthpiece in place place will ill help you not breathe in any any more more water, water, which which wil willl make the situation situation worse. Swallow Swallow several several times in quick quick succes succes sion to aid in your recovery. recovery. Trust your regulator. You £*P
can cough or snee sneeze into it and through it. You can temporarily temporarily choke if water enters the wind pipe leading leading toyour lungs. If this happens, happens, it might might be
ft? -
diffi difficul cultt or impossible impossible to breathe without without considerable effort for a fewmoments. Deliberately Deliberately relax relax your body and wait wait for your airway airway to relax relax before you resume normal breathing. breathing.
A i r S t a r v i t i o n Any time time you find yourself feeling starved starved for air, air, either below or o on n the surface, surface, or if you feel that the reg
F I G U R E 7 - 5 . I F Y O U F E E L S T A R V E D F O R A IRI R U N D E R W A T E R , S T O P W H A T Y O U A R E D O INI N G A N D R E L A X .
ulator ulator is not delivering delivering enough air, air, stop stop what you are doing, and and relax (figu (figure re 7-5). Concentrate on breathing breathing
V e r i t y W l i a l Y o u H a v e L e a r n e d
slowly and deep deeply ly until until you regain control of your your
Review the following diving diving situations and identify at least one correct action action you can take to prevent the the problem: 1. Chilling. 2. Overheating. 3. Muscle cramps. 4. Entanglement. 5. Vertigo. Vertigo. 6. Stuck Stuck power-inflator mechanism. 7. Seasickness. 8. Coughing. 9. Air starvation. starvation.
breathing and and the the feeling of air starvation starvation will will pass. Be sure to exhale exhale completely! If your cylinder valve is not fully fully open, open, it it is possible possible that the valve could be restricting your flow of air. If your your submersible pressure gauge gauge needle dips with each each inhalation inhalation,, this is a sure sign of restricte restricted d air flow. It is also the reason you should watch the SPG as you you check regulator function function during dive preparations. preparations. Open the valve yourself if you can reach behind you, you, or have your buddy open it if you cannot.
Summary Being able to solve mino minorr problems without stres stress shows that you you are a good good, skilled skilled diver. By the time you complete your train training ing,, you should feel capable of preventing or hand handling ling any problem described described here. This feeling feeling of confidence will will make you much more relaxed soyou can full fully y enjoy diving.
A S S I S T I N G O T H E R D I V E R S As a diver, you have two responsibilit responsibilities ies to your buddy. First, First, you must help to keep keep problems problems from occurring. occurring. Second, you must help your bu buddy ddy overcome overcome any problems that do occur.
NA UI Scuba D i ver
n i v l o S
m e l b o r P
m
□
As you you have learned in the preceding chapters, chapters, div div ing problems can be classified as either minor incidents or emergencies. This This section describes how to help a buddy buddy overcome minor problems. The situations described here are rare rare and should should beprevented before they ever occur. However, you need to know what what to do in case they ever do occur. Most diving diving problems problems occur at the surface rather rather than under under water water (figure (figure 7-6). 7-6). If your buddy buddy is in dis tress at the surface, surface, there are are three actions actions you must take to assist your your buddy: 1. Help your buddy establish establish buoyancy. buoyancy. 2. Get your buddy to relax, relax, breathe deeply, and rest. 3. Provide Provide assistance as needed. Give your buddy buddy assurance and encouragement, encouragement, and if if possible, help yo your ur buddy recover and overcome the difficul difficulty ty without your direct interference. interference. Establish positive buoyancy for yourself yourself and remember to control your own level of exertion. Your main task is to remain close to your buddy and give optimisti optimistic c encouragement and advice.
F IGI G U R E 7 - 7 . A F L O A T I S A G O O D W A Y T O P R O V I D E B U O Y A N C Y F O R A B I O O Y I N D I S T R E S S .
You can help your your buddy establish buoyancy buoyancy in sev eral ways. If you instruct your budd buddy y to to inflate inflate their buoyancy compensator compensator (BC (BC) or drop drop their weight belt and they respond respond appropriately, appropriately, this is the best way to help them them establish buoyancy and personal control. If they do not respond to your instructi instructions, ons, you can extend extend a surface float float to them for them to hang onto (figu (figure re 777). It might be necessa necessary ry to help them them inflate their BC or drop their their weights.
Once Once your buddy has flotation, flotation, you must get get your buddy to rest and breathe deeply. Make sure they also remember to exhale completely. Have your buddy dis card any items they are are carrying carrying in in their hands hands or have them give the the items to to you. you. Then you can discard the items if if necessary.
F IGI G U R E 7 8 . A D IVI V E R INI N D I S T R E S S A T T H E S U R F A C E U S U A L L Y H A S T H E IRI R M A S K D I S C AR A R D E D A N D T H E Y W A V E T H E IRI R A R H U S OR FLAIL IN THE WATER.
1B6
Try to getyour buddy to to solve their their own problem. If this is not possib possible, le, or your directions are not followed, followed, you will will have to provide direct assistance. The best assist
Chap ter 7-7- Problem Solving Solving
is one done casually casually - even unnoticed. Your help might consist of working out a cramp, cramp, solving solving an an equipment problem, problem, or assisting assisting your buddy to to the exit point. point. If you must help your buddy through the water, you can use various various swimming assists and tow tows. You can push your buddy through the water using using the do-si-do position. position. Have Have your bud buddy dy lie flat flat in the water with their their face up. Put Put your arm over and under under your buddy’s upper arm, grasp the top of the BC behind their their neck, and push them along. This assist provides control and allows good eye and voice voice communi communicat cation ion between the the two of you. Another push is the biceps biceps push. It is is simila similarr to the do-si-do, but you place place your left hand on thei theirr bicep instead. This This push also enables you to have good eye contact and voice communication. You can also push your buddy through the water using the the fin push. push. Have your buddy lie flat flat in the water with their legs legs straight and and their face face up. up. Place their feet against your shoulders. shoulders. Place Place your hands under under their their legs and grasp their their legs behind the knee or on the calf. With this position, you can easily push push your buddy through the water. Never Never allow allow a diver to swim to shore shore or a boat alone. You and your buddy should practice s swimming wimming assistsfrom time time to time, because you must learn learn how how to function function as both both the diver needing assistance and the diver providing assistance.
U e e l lyl y W h a t Y d u H a v e L e a r n e d Review the followi following ng questions about assisting other divers: 10. Your two responsi responsibili bilities ties to your your buddy are and 11. Most divin diving g problems occur occur at at the 12. The three steps to assisting assisting your buddy in in dis tress are , ______________________________, and __________________________
RESCUES Divers Divers usually can avoid trouble trouble under under water. If not, they can frequently frequently overcome overcome their problems either independently or with help from their buddy. buddy. Most emergencies emergencies in the water are preventable, and many usually usually occur becaus because e divers violate safety rules. rules. As a diver, you must know the fundamentals of making a ful fulll rescue rescue of an incapacitated diver, even though it is unlike unlikely ly that you wil willl ever nee need d to apply apply what you have learned. If you need to to rescue rescue someone, you will ill know how to proce proceed. ed. Further traini training ng in diver rescue techniques is avai availab lable le in the NAUI Scuba Scuba Rescue Diver course. course. This trai trainin ning g is recommended mended for every diver. A diving diving emergency occurs when a diver is uncon uncon scious or otherwise helpless helpless and, possibly, n not ot breathing. Possible causes causes include include drowning, a lung lung overexpansion injury injury,, head injury, injury, or drugs in the diver’s diver’s system system. These These injurie injuries s are rare, rare, but you must be able to help if if another diver is unable to care for thems themselves elves.. If you discover a diver in the water who appears to be unconscious, you must get them to the shore or boat as qu quick ickly ly as possible where CPR can be performed, if necessary, necessary, and medical medical assistance can be obtained. obtained.
A t t l t e S u r t a o B If a diver is apparently unconscious unconscious at the surface, surface, use the follo followi wing ng steps to perform perform a rescue: 1. Establis Establish h positive buoyancy for yourself. 2. Make contact contact with the victim victim to see seewhether they are unconscious unconscious or or able to respond. respond. 3. Pu Pull the victim victim to a face-up face-up position position and estab estab lish buoyancy for the victim. You can accom plish this by inflating the victim’s BC or dropping their weight weight belt. 4. Yell and signal for help. help. 5. Remove your your mask. 6. Remove the victim victim’s ’s mask. mask. 7. Look, listen, and feel to see if the victim victim is breathing. 8. Start artif artificia iciall respiration if the the victim is not not breathing breathing and the shore shore or boat is more than about
m
NAU I Scuba S cuba D i ver
In-Wate terr Arti Artifi fici cial al 50meters or 50yards yards away. See In-Wa Resp Respir irat atio ion n late laterr on this page for the procedure. 9. Continue Continue rescue breathing as you transport the victim to your exit point. Your instructor will train train you in the do-si-do transport that that can can be used to accomplish this. You need need both traini training ng and practice practice to become pro ficient ficient at in-water in-water artif artific icial ial respiration respiration and and rescue. Only the basic steps are learned in your your NAUI Scuba Scuba Diver certifi certificati cation on course. The NAUI Scuba Rescue Diver course course teaches teaches you further further techniques, includ including ing how to remove a victim victim’s ’s equipment equipment as well as your own as you transport the victim. victim. Their Their equipment and your own must be removed before you can can get the victim victim out of the water.
F IGI G U R E 7 - 8 . W H E N Y O U L O C A T E A M U N C O N S C I O U S D I V ER ER U N D E R W A T E R , Y O U R P R I M A R Y C O N C E R N I S G E T T INI N G T H A T D IVI V E R T O T H E S U R F A C E .
m
If you find an apparently unconscious unconscious victim victim under water, your primary primary concern is getting them them to the surface. Use Use the following following steps when rescuing a diver under water: 1. Make contact wi with th the victim victim to see whether whether they are unconscious. 2. Pu Pull the victim to a face-up position and che check ck their mask. mask. If there is any water in the mask and the diver is is not breathing, breathing, remove the mask so air air increas increasing ing in volume volume from decreased decreasedpressure will ill not force water down the victim victim’s ’s windpipe windpipe.. 3. If If the diver is breathing, hold their regulator in their their mouth while while you swim them tto o the sur face (figur (figure e 7-8). 4. If the diver is n not ot breathing, breathing, leave leave the the regulator alone. 5. You may need need to ditch the vic victim tim’s ’s weight belt to make make the victim buoyant. buoyant. This will will allow allow you to swim swim the victim victim to the surface without exerting yourself. 6. While While ascending with the victim, victim, control control your ascent to the the surface by venting air air from from the vic vic tim’s tim’s BC. Howev However, if they start to rise too too quick ly, and you you cannot control their their ascent, ascent, let them go and control your your ascent to the surface. You cannot allow allow them to make make you a second victim. victim.
7. If need be, establish buoyancy for the victim when you reach the surface. You can accomplish accomplish this by inflating inflating the victim victim’s ’s BC or removing removing the weight belt, if if this this has not already been done done. 8. Signa Signall for help. 9. Pla Place ce the victim victim in the do-si-dotransport position. position. 10. Remove Remove your your mask. 11. Remove the victim victim’s ’s mask and regulator regulator if sti stillll in place. 12. Look, listen, listen, and andfeel to seeif thevict victim im is breathing. 13. Start arti artific ficial ial respiration if the victim victim is not not breath breathing ing and you are more than than 50 meters or In-Wate ter r 50yards away away from the exit point. See In-Wa Artif Artifici icial al Respi Respirat ratio ion n for for the procedure. 14. Continue rescue breathing as you transport the victim victim to your exit point.
Use Use the followi following ng procedure to to administer administer in-water artificial respiration: 1. Pla Place ce the victi victim m in the do-si-do transport position. 2. Use your outside hand to gently tilt tilt the victim victim’s ’s head back and open the airway. airway. 3. Check the victim victim’s ’s mouth to be be sure no obstruc tions are are present.
Chapter 7- Problem Solving
additional additional train training ing and practice are required to beco become proficient. Additional training training in first first aid, CPR, lifesavlifesaving, oxygen administr administratio ation, n, and diver rescue rescue are helpful and strongl strongly y recommended.
Review the follow following ing questions questions about rescues: 13. A diving diving emergency emergency occurs when when a diver is
F IGI G U R E 7 -9- 9 . B E C O M I N G P R O F I C I E N T INI N A D M I N I S T E R I N G INI N - W A T E R A R T I F I C I A L R E S P I R A T I O N R E Q U I R E S A D D I T I O N A L TRAINING AND PRACTICE.
4. Check Check to to see if the victim victim is breathing breathing by using the following method: • Look to to see if their their chest chest is rising rising and fallin falling. g. This might be difficu difficult lt to see, depending on on the dive gear the victim victim is wearing. • Listen to hear air air escaping from their their nose nose or mouth. • Feel Feel whether whether air is hitting your chee cheek k and lips when you hold them close to their mouth. 5. If If the victim is not breathing, pinch their their nose, nose, rotate their face toward you, and give them two full breaths. 6. Give them another another breath every 5 5seco seconds. Your NAUI instruct instructor or will will showyou how to count seconds. 7. Continue giving giving the victim victim one breath every five seconds or 12 breaths per minute. minute. Take care to preven preventt water from entering the vic vic tim’s tim’s mouth and being being blown into the lungs. You must must keep water out of the victim victim’s ’s lungs. Unless the the distance to the the shore shore or boat is short, short, main maintai tain n rescue rescue breathing as you transport transport the victim victim (figure (figure 7-9)- It is most important to get get them to to the exit point where fu fullll CPR can begin, if needed, ded, and other care care can can be obtained. Learn to pace pace yourself so you will will not become too too exhausted to be of any assistance. assistance. By the end of your your NAUI Scuba Diver certification certification course, course, you will will be able to perform perform the basic steps of in-water respira respiration, tion, but
14. Four types types of recommen recommended ded emergency traini training ng are are , __________________________
15. The first first action you should take when assisting an unconscious diver at at the surface is 16. Your primary primary concern when you find an uncon scious diver diver on the bottom is to 17. The two most most important important points for providing providing in in water artificial respiration are and 18. The most important thing thing to do for a non breathing diver in thewater is to
EMERGENCIES AND FIRST AID To be a qualif qualified ied dive buddy, you must be able to assist or rescue your buddy, render proper first aid, and manage an emergency. While While fewdiving diving accidents accidents are life threaten threaten ing, injur injuries ies and fataliti fatalities es dooccur, just as in most physical activities. activities. You must be prepared to cope with injur injuries ies rang ing from cuts and bruises towounds from aquatic aquatic animal animals s to respiratory and cardiac cardiac arrest. You might be the only person availa available ble to offer immediate assistance.
NAU I Scuba S cuba D i ver
Be Prepared _
g n i v l o S
m
m e l b o r P
E D
170
To prepare yourself yourself to handle emergencies, you need need training training,, emergency emergency equipment, equipment, emergency con tact informati information on and plans, and the determination determination to act. The first rule of first aid is to “Do no harm." The best way to follow follow this rule rule is to keep keep your train training ing in first first aid, CPR, CPR, and diving rescue techniques current. Practicin Practicing g with your buddy buddy several several times a year is a goodway to keep your emergency skill skills s sharp. Emergency equipment can be exten extensive. At a mini mini mum, you should have have a first aid kit kit availab available. le. A sug sug gested contents list list is in Appendix C. Other useful equip equip ment includes an oxyg oxygen en unit unit (if you are trained trained in its its use), a cloth or space blanket, and a supply of clean clean fresh water. You must have emergency emergency equipment ready at your dive site. Replace any equipment or supplies supplies immediately immediately after after you use them them.. Oxygen is extremely valuab valuable le for for treating treating serious diving injurie injuries s such as air embolism, embolism, DCS, and near drowning cases. cases. Very few areas prohibi prohibitt the use of of oxygen equipment equipment by non-medical non-medically ly trained trained personnel. Most areas areas accept training training in in oxygen administr administration ation by a recognized agency agency such as NAUI. Check with your instructor instructor about the laws in your area. Dive boats are usual usually ly equipped with with emergency oxygen systems (figu (figure re 7-10 7-10). First First aid at at the dive site is more effective if you can administer administer oxygen. en. You must must also know know how to call call for for help. In most areas, you need need to know know who to call call for medical atten tion or medical evac evacuation uation and transport. Always Always be sure to know know the number number for summoning the local local emergency service. Divers Alert Network (DAN) is a worldwide emer gency network network that can help provide consultatio consultation, n, info infor r mation on hyperbaric chambers and diving diving physicians, physicians, transportation, transportation, and treatment through a single, 24-ho 24-hour ur emergency telephone number: (919)684-9111. DAN’s headquarters headquarters in the United States is in North Caroli Carolina. na. DAN also has emergency numbers numbers established established through through out the world to assist you you with with a diving diving emergency. emergency. Ask your NAUI instruc instructor tor for the appropriate num ber to use in your area. Write your loca locall emergency numbers, as well as the telephone number for DAN, on
F IGI G U R E 7 - 1 0 . H A V INI N G A N O X Y G E N O N I T A T Y O U R D IVI V E S ITI T E A N D BEING PROPERLY TRAINED IN ITS OPERATION ARE V I T A L W H E N T R E A T I N G D I V I N G E M E R G E N C I E S S U C H A S A I R E M B O L I S M A N D D C S .
a card, place coins for calls calls in an old film container, and include them in your first-aid kit. The last requirement for preparation preparation is being deter mined to act appropriately appropriately in an emergency. Rather Rather than become involved, involved, mostpeople tend to stand by and watch as an accident occurs. You must decide in advance that you will will act if if you are presen present at the scen scene e of a diving acci dent and if you ar are e trained and competent to deal with the situation situation.. Be sure not to interfere with professional assis tance, but be ready to help if needed and capable. capable.
B a s tet e R r s t A idi d First aid includes the following: 1. Survey Survey the accident accident scene scene to determine determine if if it it’s safe safe to render aid. 2. A quick quick examination examination of the victim victim to determine the seriousnes seriousness s of the injur injury. y. 3. Immediate Immediate treatment for llife-threa ife-threatening tening emergencies gencies such as cessation (stopping) (stopping) of breathing or arterial bleeding. 4. Treatment for less serious injur injuries ies and shock. shock. 5. Arrangements Arrangements for medical medical care care and transport. There There are are five major cate catego gorie ries s of injuries for which which IT H you should be be prepared prepared to to administer administer first first aid:
Chapter 7- Problem Solving
acquire acquire these skills or refreshed your knowledge knowledge for one or two years, you should should complete one of the programs availa available ble through through various various agencies. agencies. As a diver, you should also comp complete lete training training in oxyg oxygen en administration through a NAUI instructor.
A q u a t i c L i f e I n j u r i e s General first first aid aid traini training ng does not cover treatment of injuries injuries from aquatic life, although most of the general general procedures also apply to this specialty area. General guide lines are presented here. Your instructor instructor wil willl give you spe cific cific treatments treatmentsfor injuries injuries from aquatic life in in your area. F IGI G U R E 7 - 1 1 . I N A D D I T IOI O N T D A D M I N ISI S T E R I N G O X Y G E N F O R A DIVING EMERGENCY YOU MUST ALSO TREAT FOR S H O C K , M O N I T O R T H E V ICI C T I M , A N D O B T A I N T H E IRI R T R A N S P O R T T O M E D I C A L A T T EN T I O N .
m
• Severe bleeding. bleeding. • Respiratory failure. failure. • Heart Heart failure. failure. • Shoc Shock. k. • Serious diving accidents such as lung overexpan overexpan sion injurie injuries s and DCS. DCS. Emergency training in first aid will teach you how to properly respo respond nd in the first first four areas. areas. First aid for air air embolism and DCS also includes lying the victim down down and and maintai maintaining ning their their respiration and circul circulati ation. on. You must also treat for shock, adminis adminis ter oxy oxyge gen if available, available, constantly monitor the victim, and transport the victim victim to the nearest appropriate medical facil facility ity or operational recomp recompress ression ion chamber chamber (figure 7-11). NAUI recommends that that you take the NAUI Scuba Scuba Rescue Diver course, course, in which which you can learn learn and prac prac tice accident manag management. ement. See your instructor instructor for more information information about this important important course. course.
C P R a nd Oxygen Administration You should have training in first aid and artificial rrwi respiration. Everyone, diver or not, should be be prepared Ls!^i !^ i to administer administer first aid and especially cardiopulmonary resuscitation resuscitation (CP (CPR). R). If you have not taken taken courses rses to
Prevention Aggres Aggressive sive animal animal behavior behavior under water is rare. Any injur injury y you might receive from an aquatic a anima nimall will ill almost almost always result from a defensive defensive action action on the part of the the creature, creature, but it will will hurt anyway! Remember ember that nearly all all animals animals will will attack attack if they they feel feel cornere cornered d or threatened. threatened. Avoid potential potential problems with aquatic aquatic life in your your area by learnin learning g how to to identify hazardo hazardous us creatures creatures and how to avoid them. Remember that when you are diving, you are enter ing the home home of these creatures. Respect the creatures and their home home,, and they will leave you alone. If you act aggressive aggressively ly towards ards any marine life, they will attack to protect themselves. selves. Some are very territo territoria rial,l, and will will attack if if you approach their home.
Treatment Injuries Injuries from aquatic lif life e are classified in one or more of the followi following ng categories: • Punctures • Stings Stings • Bites and lacerations lacerations • Amputations Sea urchins, spiny fish, or stingrays stingrays can cause punc ture wounds. If possible, remove any materia materiall in the wound. Toxins might have been injected and must be treated by soaking soaking thewounded area in water water as hot as the II victim victim can can tolerate for at least 20minutes. minutes. Some divers divers
i b l e m S o l v i n g
NAU I Scuba Sc uba D i ver
i v l o S
m e l b o r P
might be hypersensitive hypersensitive to wounds from marine marine animals. animals. Get the victim victim to medical medical attention as soon as possible. Je Jellyfish or coral can cause stings. Remove the sting ing materials and apply a neutralizing neutralizing agent. Your instructor will will tell tell you the correct proce procedure dure for neutraliz neutraliz ing stings stings caus caused ed by creatures creatures in your local local area. Medical attention is require required d if the injury injury is serious or the victim victim showssigns or symptoms of an aller allergic gic reaction. reaction. Almost any aquatic animal can bite. First aid can range from simple, antiseptic cleanin cleaning g of the wound to control of serious bleeding. Medical Medical attention is neces ces sary if the wound is serious, serious, signif significa icant nt blood loss loss occurs, or the victim victim shows signs or symptoms symptoms of an allergic reaction. Injuries Injuries from aquatic life are asvaried as the diving environment. You must knowwhat wounds are likely likely to occur in a given area as well as the first aid for them. Even more important, important, lear learn n how to avoid being wounded.
V e r i f y W h a t Y o u H a v e L e a r n e d
Diving safety safety is primar primarily ily a matter of knowing knowing the rules, followi following ng them, and being being prepared. prepared. Being Being aware aware of safe safe diving practices, both both generally and loc locally, ally, and following following them wil willl do more than anything anything else to ensure your your safety. If something unexpected unexpected does occur, being prepared prepared to deal with the situation situation can can make it simply something something easily dealt with rather than a serious problem. Diving safety primarily involves attitude. Safety occurs when a diver respec respects the environment and wants to be properly properly prepared prepared for diving. For divers divers who are prepared for for emergencies and follow follow the buddy system as well as other good diving practices, safety is simply a byproduct of that attitude. You should should abide by the NAUI Recommended Diving Diving Practices, Practices, summarized in Appen Appendix B. By apply ing these these principles, principles, you wil willl see for yourself that that the a ccident ” is not merely a saying “Diving safety is no accident play play on words.
Review the followi following ng questions about emergenc emergencies ies and first aid: 19. Four Four requirements for being prepared to handle handle a diving diving emergency emergency are
R E S P O N S I B L E S C U B A D I V IN IN 6 P R A C T I C E S
______________________________, and 20. To ensure ensure that your ski skills lls wil willl be adequate adequate in an emergency, you should and ______________________________
21. Four Four recommended items of equipment for for emergencies are
and 22.
172
SAFETY IN SUMMARY
is a worldwide network of hyperbaric chambers and diving physicians who provide provide consultation consultation for transportation transportation and treatment of diving accidents. accidents.
You must be be trained trained for what you plan plan to do do or might have to do in diving, diving, and you must must resist the the temptation to teach teach others unless you becom become certified certified as a NAUI NAUI instructor. Your training training should continue with with advanced, advanced, specialt specialty, y, and refresher refresher courses to keep your knowledge knowledge and skills skills current current and progressing. progressing. Only dive when when you are feeling well, mentally and physically. physically. Annual physical examinations examinations are are impor impor tant. Do not dive under the influence of drugs, includ includ ing prior indulgence in alcohol. Keep yourself in good physical condition, condition, know your limits, limits, dive within within them, and mainta maintain in a reserve of energy and and air air as margins of safety safety.. If you grow grow cold, tired, ill, ill, or low on air while diving, diving, exit the water immediately. You must must properly maintai maintain n your equipment according to the manufactu manufacturer' rer's s recommendations recommendations and check it before before each dive. Have it serviced serviced professionally professionally as the manufactur manufacturer er recommend recommends, and use all all recom recom mended nded equipment when diving. Be properly weigh weighted, ted,
Chapter 7- Problem Solving
and particu particularl larly y avoid diving with exce excess ss ballast. Never Never loan loan your equipment to anyone anyone not certified certified to dive. Know the location location where you will will dive. Respect Respect the the environment, and avoid dangero dangerous us sites and poor poor diving conditions. Fly Fly the diver down down flag to warn warn boaters boaters of of your presence, and then dive near that flag. flag. Exercise moderation with depth depth and time limits. limits. Take the time to properly plan plan your dive, dive, and follow follow
co
your plan. plan. Know the rules of the buddy system and abide by them them for your own enjoyment and security. J Dive regularly, or renew your skills after a period of inacti inactivit vity y before diving diving again. again. Log your dives to remem ber the details details and experiences. If you follow the Recomm Recommended Diving Practices presented ented to you by your NAUI instructor instructor from from the outset of your training, training, they they will will soon become part of your routine and you you will will perform perform them with little little effort. effort. Make this your goal, and you you wil willl set yourself yourself on a good course course to avoid the hazards of diving. Safety is
□
an attitude, and this is reflected in the NAUI motto motto “Dive Safety Through Educatio Edu cation. n. ”
173
NA UI Scuba Diver Div er
L E A R N I N G GO ALS t n e m n o r i v n E g n i v i D
In this chapter chapter you you will: will: • Learn about the physical physical characte characterist ristics ics of dive sites. • Be introduced introduced to the types of water movement movement and how it can can affect your your dive. • Learn about the the different categorie categories s of marine life and how to avoid situations situations with with them. • Be introduced to the positive impacts you can have on the underwater environment. • Learn about about some of the popular diving areas areas throughout the world. Underwater conditions vary vary from one part of the world to another. Visib Visibilit ility, y, water temperature, temperature, waves, currents, and other factors are all all different different in each dive area. These differences differences influenc influence e the way you dres dress s for a dive and and the techniques you use. No matter where you dive, you will will discover special requiremen requirements ts pertaining pertaining to diving in that area. Before Before you go diving diving someplace you have never never been before, you must must learn about the environmental conditions that could affect your d divin iving g and know how how the local local divers deal with them. You must also consider other environmental environmental and physical physical variat variations ions,, such as the the season of the year, the weather, dive-site dive-site characteris characteristics, tics, and shore conditions. The continental continental United States is a good good example of a country with some of the most varied varied diving diving conditions conditions in the world. The underwater environments of the United States include include diverse areas, such as: as: • Oil rigs off Louisiana and California. California. • Tropical Tropical waters off the the coast coast of Florida Florida.. • Cold waters in the Great Lakes, Lakes, New England, England, and Alaska. • Kelp Kelp forest forests s off the coast coast of California. California. These environments are extremely different, different, and each requires certain specific specific skills, skills, techniques, and equipment. equipment. This chapter examines ways ways dive site characteri characteristics stics and shore shore conditions conditions affect your divi diving ng techniques in different areas areas.. It conside considers rs variations in tempera temperature ture,,
176
visibili visibility, ty, and aquatic life. It also address resses es conservation conservation and ways ways you can help preserve preserve the underwater environ environ ment. ment. Your instructor wi willll supplement this material material by explaining explaining the ways ways local conditions affect diving near your home.
P H Y S I C A L C H A R A C T E R ISI S T I C S O F A S I T E A variet variety y of character characteristic istics s determine the type type of site and bottom conditions. The characteri characteristics stics of the the site will ill dictate dictate how you enter and exit the water as well as how you dive.
Divers will will dive almost anywhere there there is water, but they are frequently attracted attracted to interesting interesting underwater formations. formations. These These formations can be man-m man-made, ade, such such as an artif artifici icial al reef, reef, oil rig, breakwater, breakwater, jetty, jetty, or ship ship wreck (figu (figure re 8-1). Man-made sites can be as fascinat fascinat ing as any natural natural underwater underwater formation. In particula particular, r, many many divers fin find d shipwrecks to be among the most exciting dive sites (figure (figure 8-2). 8-2).
F I G U R E 8 1 , G I V INI N G S I T E S V A R Y W I D E LYL Y . O I L R I G S A R E O N E E X A M P L E O F A M A N - M A D E S I T E T H A T P R O VID E S G O O D D IV I N G .
Chapter 8- Diving Environment
i v i n g E n v i r o n m e n t
F IGI G U R E 8 - 2 . S H I P W R E C K S A R E A L S O P O P U L A R D IVI V E S ITI T E S .
F IGI G U R E 8 -4- 4 . D I V INI N G I N S I D E W R E C K S A L S O R E Q U I R E S S P E C I A L T R A IN I N G A N D E Q U I P M E N T .
and caverns or divin diving g beneath the ice of frozen lakes. lakes. While While there are many typ types es of fascinatin fascinating g places to to explore under under water, many of them require special trai train n ing beyond beyond the the NAUI Scuba Diver certifi certificat cation ion course. course. Any diving environment that does not not allow allow direct vertic vertical al access to the the surface is called called an overhead environment. Overhead Overhead environments inclu include de caves, the interiors interiors of wrecks, and waters beneath the ice or heavy kelp (figures (figures 8-3,8-4, and 8-5). These These environ environ ments ments are are highly highly specialized. specialized. They require additional special equipment and training no matter how much experience a diver might have div diving ing under other condi tions. Even instructors ne need ed special trainin training g for these types of environments. environments.
F I G U R E 8 -3- 3 . C A V E D IVI V I N G R E Q U I R E S S P E C I A L T R A I N I N G A N D EQUIPMENT.
Natural Natural dive sites sites include submarine submarine canyons with sheer drop-offs, lakes, rivers, and coral coral and rock reefs. Natural Natural sites have the the benefit of marine marine growth that might be thousands thousands of years old. Speci Speciall ally y trained divers also enjoy enjoy the thril thrilll of exploring underwater underwater caves caves
m
E N T R I E S A N D E X ITI T S The easiest easiest diving diving is usua usually lly from boats, boats, and in many situations, situations, boat diving diving offers some some of the the best best diving available. Beach diving is a popular alternative for many many divers and can be extremely extremely enjoyable. Beach diving is generally more strenuous than boat diving, diving, but both present present varied varied and unique diving situations (figure (figure 8-6). 8-6).
m
177
NA UI Scuba Sc uba D i ver
t n e m n o r i v n E g n i v i D
F IGI G U R E 8 - 5 . D IVI V INI N G H E R I C E P R E S E N T S U N I Q U E C H A L L EN EN G E S T O E V E N E X P E R IEI E N C E D D I V ER ER S .
One of the most challen challengin ging g aspects of beach diving diving can be getting to the water’ water’s s edge. Beach Beach access can can be diffi difficu cult lt in areas areas with with steep cliffs cliffs and rugged shores. To dive in some of the more remote areas al along ong coastlines, coastlines, you might need need to walk or climb over rugge rugged d terrain, terrain, cov ering considerable considerable distances distances either wearing or carryi carrying ng your gear. This This can be exhausting exhausting and hazardous. To dive under these theseconditions, conditions, you must knowyour capa capabil bil ities and limitation limitations s and plan for them. When diving in these areas, also make sure that you have the energy to safely return to your starting starting point after after the dive. As you enter enter the water, water, shoreline shoreline conditions can can cre cre ate other problems. The shape of the bottom can affect currents and wave wave action. The bottom bottom might slope gradually gradually,, drop off suddenly, suddenly, or have scattered holes and rocks. The composition of the the bottom bottom will ill affect the way you enter the water (fig (figure ure 8-7). 8-7). Whenever you dive in a new area, you need an ori ori entation entation to the dive site site.. You need need to to knowwhat to look for and what to avo avoid, id, as well as any diving techniques ] \J J that might be be unique to that area. This can be be learned by diving in new areas areas with a NAUI Instructor, NAUI
178
F IGI G U R E 8 - 7 . R O C X E N T R I ES E S C A N B E H A ZA ZA R D O U S . Y O U M U S T P U N T H E E N T R Y B E F O R E A T T E M P T I N G ITI T .
Divemaster, or other experienced experienced loca locall divers (figur (figure e 8-8). Always seek informa information tion about new new dive sites from experienced divers. As you gain experience and parti partici ci pate in advanced courses, you will will be able to explore new areas confidently and without supervision.
B o t t o m Conditions The bottom bottom composition of a site also affects your diving. This is true whether whether you you dive in a quarry, lake, river, or ocean.
C h apa p tete r 8 - 18625673 / '
F IGIG U R E 8 -8- 8 . A I M S G E T A N O R I EN E N T A T IOIO N T O A N EW EW A R E A FR O M
F IGI G U R E 8 -9- 9 . R I C K Y A R E A S H IDI D E M A N Y M A R I N E C R E A T U R E S .
A N E X P E R I E N C E D D I V E R W H O K N O W S T H E A R E A .
□
EH
Usually, Usually, you can expect expect the underwater terrain terrain at the dive site to be an extension of the shoreline. If the shore shore is rocky and and rugged, ged, you will will probably find simil similar ar underwater underwater conditions. Awide, sandy beach usually usually indicates a vast expanse xpanse of sand sand offshore. offshore. There are exceptions, ptions, so it helps to check with other divers regard ing an unfamil unfamiliar iar site. Some information about botto bottom m conditions is also also available available on navigation charts used used for boating. In most case cases, s, the the greater greater vertical relief relief (wal (wall) l) there there is to a dive site and the more aquatic aquatic plants plants present, the greater the amount of marine marine life life in the area (figur (figure e 89). Flat Flat stretches stretches of bottom tend to be lackin lacking g in readi readily ly visible visible life life compared with kelp forests forests and coral coral reefs. Divers tend to to seek areas areas with plenty plenty of marine marine life life to be seen, which makes divi diving ng more interesting. You find many different different bottom bottom compositions under water. These These include include mud, silt, clay, clay, sand, pebbles, bles, rocks, rocks, and coral. coral. Mud and silt bottom bottoms are easily easily stirred up. This can reduce visib visibililit ity y to zero because of suspended sediment. Sand bottoms bottoms have better better visib visibili ility ty,, but these these tend to be underwater underwater deser deserts visua visually lly,, because because most of the the life life is in and under under the the sand, sand, or flees at your approach. Rocky
bottoms bottoms provide a good base for marin marine e plants plants and provide provide many holes and c crevices revices that aquatic animals use as homes. Aquatic plants do not growwell in tropical tropical waters, waters, but coral coral thrives thrives in these these waters and provides excellent diving. Barnacles, Barnacles, rocks, rocks, and underwate underwaterr formations might might have sharp sharp edges, soyou must have good buoyan buoyan cy control control to prevent cuts and scratches when diving diving in in areas with these features. Varying Varying bottom bottom compositions require different different div ing techniques. You must learn learn one technique for a beach entry on a sandy bottom bottom that provides good foot ing and another for a muddy bottom, which which can pose pose an entirel entirely y different set of challenges. Mud can also be very slippery slippery when you are entering or exiting exiting the water. water. Once Once you have entered entered the the water, you wil willl find find that that you must must move move carefully carefully to avoid stirrin stirring g up a muddy muddy or silty bottom. Sandy bottoms do not cloud the water as easily easily as muddy or silty bottoms bottoms.. Coral and rock reefs reefs usual usually ly provide provide the bes bestt visibi visibilit lity y as well as many interesting things to see. Once Once you begin diving diving in in open water, you you will ill better appreciate the ways bottom composition is one of the the many elements that affect affect your dive.
NA UI Scuba Sc uba D i ver
Review the following following questions abou aboutt the physical physical characteristics of a site: 1. Who is best qualifi qualified ed to give you an orientati orientation on to a new area?
t n e m n o r i v n E
2. Two types of overhead environment environments s that that require special training are and _____________
3.
g n i v i D
Two types of man-made dive dive sites are and
4. Two types of natu natura rall dive sites are and 5. The bottom of a dive site can can be composed of . or 6. The underwater environment environment is usuall usually y an extensio extension n of th the . ____________________
__________________
W A T E R C O N D I T IOI O N S Water temperat temperature ure and visibi visibility lity are probably the the two two most most important factors in determining determining the ease ease and comfort comfort of your dive. Diving in warm, cl clear ear water is rel atively simple, beca because use you you must wear wear only a minima minimall amount of insulatio insulation n and it it is always easy to see where you are. are. Diving in colder, darker water is mo more re difficult difficult because because you must wear more insula insulatio tion n to be comfort able and it is is not always possible possible to tell exactly exactly where things are under water beyond the the range of your v vision. ision.
V I S I B I L I T Y
m
100
A major factor affecting all all dives is the underwater underwater visibi visibilit lity, y, which which can range from zero towell over 30 meters (100 feet). Diving in in water where thevisibi visibilit lity y is severely restricted can be be hazardous, and zero-visibility zero-visibility diving diving requires special equipment, equipment, train training ing,, and procedures.
F IGI G U R E 8 1 0 . A B U D D Y LIL I N E 1818 O N E W A Y O F M A I N T A I N I N G C O N T A C T I W A T ER E R W I T H P O O R V I S IBI B ILI L ITI T Y .
If you arrive arrive at a site and find that you cannot see any thing thing under water, you should postpone the dive unti untill a day when the the visibi visibility lity is better. Zero-visibility diving is a necessaiy necessaiy part of search-and-re -and-recovery covery diving training, training, but it is not fun or safewhen you are just learning learning to dive. dive. The local locale, e, seasons, weather, water movement, composition of the bottom, and other factors affect underw underwater ater visibility. visibility. For examp example, le, in California California visibili visibili ty is usually usually best best during the calm ffal alll mo month nths, s, and worst orst during the winter rains and storm storms. s. In the Sea of Cortez, Cor tez, in Mexico, there is good goodvisi visibi bilit lity y in the summe summerr months months and and poor poor visib visibilit ility y in the winter month months. s. Tidal changes changes also also affect affect visibil visibility. ity. SeeTides on page 183for informat information ion about tides tides. Several Several problems relate to visib visibili ility ty.. The most com mon mo n is disorientation. disorientation. With limited visibility, visibility, you you can IT ^ l become disoriented and dizzy from a lack of visual visual refer references ences while while you are are subme submerged. You can avoid avoid this by not diving in poor visibilit visibility y until until you have bee been n trained in the prope properr techniqu techniques. es. Entanglement in fishing fishing line and other debris can also be a serious problem in lowvisibility visibility conditio conditions. ns. There are special special techniques for diving diving in limited visibi visibility lity.. Divers can hold hands to stay together ether or use use a buddy buddy line line (figure (figure 8-10). 8-10). A buddy line line is a short length of L rope up to 2 meters (6 (6 feet) in length, with with a loop at each end. Each Each diver diver in the the buddy team holds one end of the line to maintain maintain contact. contact. Limited-visibility diving is a
Chapter 8- Diving Environment
specialty area. area. Your instructor will ill cover cover any special special tech niques niques that relate to visib visibili ility ty where where you will ill be diving. In extremely extremely clear water, estimating distances distances can be diffi difficul cultt (figur (figure e 8-11). The surface, your boat, boat, and other other things appear closer than they are. When this happens, it it is is easy to exceed your planned planned depth, because some objects will ill be deeper and furthe furtherr away than they appear, appear, as well. well. Under these conditions, conditions, it is importan importantt to monito monitorr your depth gauge gauge even more frequently than normal. Whether visib visibilility ity is good or poor, you can see see why you and your buddy must stay close together under water. In poor visi visibi bilit lity, y, it is easy easy to become become separated separated and lose track of one another. If you are unable to find . your buddy buddy withi within n one minute under these these conditions, you must surface, surface, using the standard technique technique to search for a lost buddy. buddy. In good visibi visibilit lity, y, it is easy to get too far apart, which means you will will be unable unable to help if your your dive buddy needs assistance. Begin Begin developing developing gooddiving diving habits from from the very first first time time you go under water. If you want to be considered a good goodbuddy, learn learn to stay within within touching distance of your buddy without without getting in their their way.
TEMPERATURE Water temperature temperature can range from freezing to over 30°C (86 (86°F). °F). Diving in water water colder colder than abou aboutt 26°C (79 (79°F) °F) normally normally requires that you wear som some type type of diving suit, depending depending on the the duration of your dive, your activity activity level during the dive, and your individ individual ual physi ology. As a rule, the colder the water, the more more insula insula tion you will need need to wear. wear. Almost Almost all diving requires requires some type of insula insulatio tion n because because the water temperature will ill be colder than your body’s skin temperature. Even if you usually usually dive in reasonably reasonably warm water, water, you will will need need toprevent getting chill chilled ed because of the water’s water’s capacity capacity to conduct and absorb bsorb heat, you will ill chill ill rapidl rapidly y if you do not wear wear adequate protection. protection. Water temperature is always a major major factor to consider when planning planning a dive. In mo most st cases, the deeper deeper you dive, the colder colder the water water temperature. In freshwater lakes, a phenomenon known known as a thermocline will will appear appear in the summertim summertime e (figure (figure 8-12 8-12). ). This is a thin thin zone of radica radicall change in water temperature temperature between the surface surface and the bottom layers.
Warmer water
Thermocline (Depth Varies)
Colder water
Bottom
F IGI G U R E 8 1 1 . C O R A L R E EFE F S U S U A L L Y I A V E E X C a L E N T V I S IBI B ILI L ITI T Y T H A T C A N B E G R EA E A T ER E R I A N S O M E T E R S (1( 1 0 0 R E T ) .
F IGI G U R E 8 1 2 . A T H E R M O C L INI N E ISI S A D I S T INI N C T , T H INI N Z O N E O F R A D I C A L C H A N G E I N W A T ER T E M P E R A T U R E B E T W E E N S U R F A C E A N D B O T T O M L A Y ER ER S O F A L A K E .
181
NA UI Scuba Sc uba D i ver
The two layers of water can vary vary in temperature temperature as much as 10°C 10°C (20 (20°F). °F). They remain distinctly s sepa eparate rated d and do not mix. If your diving suit is is appropriate appropriate for only the surface water temperature, you might find that that this drastic drastic temperature change at depth would force an early early end to your dive. Thermoclines Thermoclines are commonly found in many many lakes, but they also occur in the ocean. ocean. Freshwater lakes also experience changes in water temperature temperature throughout the year. During During the fall fall,, as the the surface water cools, the wind mixes it it with the deeper water and eliminates the the thermocline. rmocline. During the win win ter, the surface temperature temperature of a freshwater lake can drop drop to near freezing and a reverse reverse thermocline thermocline devel ops, with the colder colder water as the top layer, and warmer
M O V I N G W A TER A N O IT S E F FE C T S Water is heavy. heavy. If you think think about about the the weight of of a sealed can of water and how it would ffeel eel to have one dropped on your foot, you can can imagine the enormous potential potential energy contained in in a large large amount of moving water. It is useless to fight against strong water movement, such as a strong current, becauseyou cannot effectively effectively swim against it. it. It is possible to use the movement of the water to assist assistyou in diving, and this is someth something ing you will will leam during during your NAUI Scuba Diver certification certification course course.. You must understand what setswater into into motion, motion, how the water moves, and howto function function effectively in moving water. This understanding will will help you plan ahead to cope with with the the movement of water and use it to your advantage.
water as the lower layer. During During the spring, as the sur face water warms, the wind mixes it it with with the deepe deeper water and eliminates eliminates the reverse reverse thermocline. You must obtain infor informatio mation n about the water tem perature at the depths to which which you pla plan n to dive before entering entering the the water. This information is usually available available from loca locall instructors, instructors, divemasters, or dive stores. You must must select suitable thermal thermal protection for both the water water temperature temperature and and your indiv individu idual al physiolo physiological gical needs needs.
Review the following following questions about water water conditions: 7. A thermocline thermocline is a
8.
, _____________
,
,and and
_________________
affect affectvisibility. visibility. 9. Diving in water with no visibi visibility lity can cause cause
can
As wind blows acros across s the water, it it transfers transfers its ener gy to the water. The water water starts to push into peaks and valle valleys ys to become waves. In the open ocean, these these waves are called swells. swells. With increasing wind, or as the wind blows blows for a longer time, larger larger swells swells form. Unless the swells are quite quite large and the wind blow blows s hard, waves usuall usually y do not break in the open ocean. ocean. The energy energy of the waves waves - but not the water water itself itself can trave travell across thousands thousands of miles of ocean. As waves waves enter shallow shallow water water and are affected by by the bottom, bottom, they break and form surf. The larger the waves, waves, the larger the surf. The su rf zone is the area area where waves waves are breaking as the water gets shallower shallower closer to shore (figure (figure 8-13). In coastal areas where beach beach diving is popular, divers must go through through the surf surf zone to enter the water. Chapter 3provides an introduct introduction ion to surf entries. Your instructor will cover these entries in detail if they are common in your diving diving area. Surge is the underwater movement movement of water you will ill experience when when diving diving in areas close to a shore shore with wave action. When you you are in shallow shallow water close close to shore shore and there are large waves, you will ill feel the effects of surge. As the waves move over you toward toward the shore, shore, the surge will ill tend to push your body first away from and and then toward the shore.
Chapter 8- Diving Environment
Tides Tides can also affect your diving if if you are using a small small boat that is docked or launched launched at a marina. marina. As the tide goes out, out, floa floating ting dock and laun launch ch ramps can become quite stee steep. Launch Launch ramps in parti particu cula larr can be extremely slippery, because because the marine plants that grow on them are are exposed at low tide. Water movement because because of tides tides can also affect underw underwater ater visibility. visibility. The best diving visibility visibility is usually usually during during high tide. tide. There are exceptions, exceptions, and you will ill learn mo more re about local tides from your instructor as part of your open open water training. training.
F IGI G U R E 8 1 3 . S U R F F O R M S W H E N W A V E S B R E A K C LO LO S E TO SHORE.
In most areas with large waves, waves, surf, and heavy surge surge, visibi visibility lity will will be poor. Different beach conditions conditions require different entry-and-exit entry-and-exit techniques, so always get an orientation to any new new diving area from a NAUI Instructor Instructor or a NAUI Divemaster.
Tides cause water movemen movementt in many areas. Tides are caused caused by the gravita gravitation tional al attractio attraction n betwee between n the the Earth, Earth, the Moon, and and the Sun. In different different areas of the world, the water water level change between between low tide and high tide can range range from less less than than 0.3 meters (1 foot foot)) to 12 meters (40 feet). feet). Usually, Usually, the difference betwe between en low and high tide is o only nly a few feet of water. water. The change in the water level at a dive site due to the tide can cause problems problems while while you you are on your dive if you do not plan for it. For example, when when the tide is in, or high, the water extends further further onto the beach, covering rocks rocks that are just outside the the waves. This makes it easy to enter the water, because you can can swim over the rocks. When the tide is out, or low, the water water reced recedes, es, uncovering any rocks. If this happens while while you are in the water, you might might be forced to climb b back ack over the rocks to return to the beach. This This can be much more mo re difficu difficult lt and dangerous dangerous than swimming over them. You avoid this by timing your dive properly.
A current is is the the movem movement ent ofwater in a particul particular ar direction. Currents Currents are like rivers or stream streams s within the the ocean. ocean. Winds, tides tides,, gravity, and the the Earth Earth’s ’s rotation cause currents in the oceans. oceans. Rivers have a generally generally constant current current flow due to gravity. You must consider currents when you plan a dive, because attempting to swim against a strong current current can exhaust exhaust you very very quickly. Usually, Usually, you begin a dive into the current, no matter h how ow slight it is. If your your entry and and exit points are the same, same, you can use the current current to help you return return to your exit point at at the end end of your dive. If you are diving from an anchored anchored boat, boat, a trai traill line line 30 meters (100 feet) long with a buoy at the end should be extend extended behind the boat boat (figu (figure re 8-14). 8-14). This way, if if you acciden accidentally tally end your dive downcurrent from the the boat, you you will will usually usually be able to grab grab the the line and pull pull yourself yourself back to the boat. In the NAUI Advanced Advanced Scuba Diver Diver course, course, you can learn learn how todrift dive. When you drift drift dive, you use the current current to move move you along, along, planning your exit downcurrent of your entry point.
F IGI G U R E 8 1 4 . B E S U R E T O U S E A T R A I L L INI N E W H E N Y O U D IVI V E F R O M A B O A T I N A N A R E A T H A T M I G H T H A V E A C U R R E N T
NAU I Scuba D i ver
Currents can be separated into into three categories: • Standing
Rip currents occur occur near the shore and form when wave or wind action action pushes water up onto the shore shore and the water then funnels funnels back out to sea through a narrow narrow
m
t n e m n o r i v n E g n i v i D
'
• Transitory Standing currents currents are regular, steady currents that donot chang change e very much, if at all. all. In many parts parts of the world, longshore longshore currents currents normally normally flow in one direction along the coast. coast. This is is a good example of a standing current. The Gulf Gulf Stream in the Atlantic Atlantic Ocean flows from the Caribbean north toward Nova Nova Scotia Scotia and then around to Europe. This is an an open-ocean n-ocean standing cur cur rent. Rivers Rivers and streams are also examples of standing standing currents. currents. You must be aware of the speed and directi direction on of any standing c current urrent present where where you plan to dive and account account for it in your dive plan. Tidal currents currents are caused by tides. When these cur cur rents pass through restricted restricted areas, they can be quite strong, even strong enough to sweep you away no mat matter ter how hard you swim swim.. Most divers cannot swim any faster than 1.8 kilometers per per hour (1 knot) for longer than a few minutes. Many Many tidal tidal current currents s are 3-7 kilometers kilometers per hour (2 knots) to 9 kilometers per per hour (5 (5 knots) or faster. faster. In areas with strong tidal currents, you must must con sult tide and and current tables tables,, which are readily available, available, slack-wate water r period to help plan your your dives for slack periods s only (a time when there is no tidal current). Transitory currents are currents that that suddenly appear and disappea disappear. r. A good example of a transitor transitory y current current is a rip current current caused by surf (figur (figure e 8-15). 8-15). T
i d a l
passage. This passage or restriction restriction can be a narrow opening in a reef, sandbar, sandbar, or other large formation otherwise channeli channeling ng the return return of water to the ocean. The offshore flow of a rip curren currentt is narrow narrow and can be be quite quite strong. If you find yourself being carried away from shore shore or you are unable unable to make progress progress when when trying trying to return return to the the beach, beach, you might be in a rip current. current. You can escape these these currents currents by swimming swimming across the rip current, current, usual usually ly parall parallel el to the shore. shore. Once you are out of the current, you can then turn towards shore shore and swim in. The rip current current might empty empty into a longshore longshore current. If you try to swim out of the rip current and into the longshore longshore current, the longshore longshore current will will push you back into the rip current. If this happens happens,, swim out of the the rip current current in the other direction. direction. With experience, you will ill be able to easily easily identify identify rip currents. currents. If they occur in your area, your instructor will familia familiarize rize you with them and the the areas areas in which they appear. You can also also use currents to carry carry you to your planned exit exit point, which which adds adds to to the ease and enjoy ment of your dive. When you take the NAUI Advanced Advanced Scuba Diver Diver course, you wil willl learn learn how to to use use currents to make ocean ocean diving diving easier and more exciting. exciting. As a new new diver, you must learn more about local local currents and how to recognize them before you attempt to make unsupervised unsupervised dives. dives. The best way to to accomplish accomplish this is by training training with with a NAUI instructor who has experie experience nce in your local area. area. Even with with experience, advanced divers should ask local divers about local current and diving conditions when they they plan plan on diving diving at a new new site. If you travel travel to a new area where conditions conditions differ differ from those where you you trained, get get a local orientation. For examp example, le, if all all of your diving diving has been in freshwater lakes, you wil willl need
F IGI G U R E 8 1 5 . Y O U C A N E A S I L Y I D E N T IFI F Y R IPI P C U R R E N T S O N C E Y O U K N O W W H A T T H E Y L O O K L I K E .
184
an orientatio orientation n to dive in the ocean, ocean, and vice versa. Or, if you learned in Florida Florida but want to div dive e in the kelp forests forests of Califor California nia,, you also need need an orientation. orientation.
m
C hah a p tet e r 8 -18625673 "" /
Review the following following questions questions about the movement movement of water: 10. Three causes of water water movement are and and . 11. To escape from a rip current, current, you must swim the current. 12. You always begin a dive from an anchored anchored boat the current. 13. Tides are are caused by the th e of the and __________________
___________________
________________
________________
____________________
M A R I N E L IFI F E The many different types of life in the underwater underwater world make diving interesting. There are thousan thousands of ani mals and plants to interest and amazeyou. There is beau ty andcolor that surpa surpasses anything you can imagine. It is natur natural al to beconcerned aboutdangerous animals animals and plants, given the overblown portrayal of dangerous marine life life you have seen in movies and television. Asyou will will learn, these dramatic portrayals are usually usually grossexaggera tions of the dangers posed by these creatures. Mostdivers look forward to encounters with underwater life. There are are potentially potentially dangerous animals and plants under water, just as there there are potenti potentiall ally y dangerous dangerous plants and animals animals on land. You probably know how to avoid attracting attracting or agitating agitating bears or snakes snakes when you gocamping, and how to handle handle aggressive dogs in your your own neighborhood neighborhood.. By reading, or through traini training ng and experience, you have learned learned how to recognize and avoid dangerou dangerous animals animals soyou can go hiking, hiking, camp ing, or walking walking around your neighborhood without without fear. Going under under water water is simil similar ar to going hiking or camping. Some Some aquatic animals animals can be be just as harmful harmful as a snake or bear, but as you lear learn n more about them, you will will be able able to encounter the them, m, with confidence. The most dangerous creature you are are like likely ly to meet under water water is another diver.
Aggre Aggressiv ssive e animal animal behavior behavior is rare under water. Any injury injury you might receive receive from from an aquatic aquatic anima animall almost certai certainly nly would result from a defensive defensive action on the the part of the creature. creature. Rememb Remember er that nearly nearly all a ll animals will attack if if they feel cornere cornered d or threatene threatened, d, or their territory territory is invaded. You might might injure injure yourself by accidentally encoun tering an animal animal or disturbing it. Avoid potential prob prob lems with hazardous hazardous marine life life by learning to identify such creatures that exist in your area. Each Each region has its ow own n hazard hazardous ous animals. Identifica Identification tion and avoid ance are your your keys to safety. A good rule is is to touch nothing - you might kill kill or injure injure creatures that are harmless harmless to you, as well well as provoke others. others. During your NAUI Scuba Diver certificatio certification n course, course, your instructor wil willl teach you you about about animals in in your area. You must must obtain similar similar information information about about the marine life in in each area area that you visit. Learning Learning what marine marine life life lives lives in a given area is one of the reasons for getting getting a formal orientation orientation for diving diving in in a new region. region. Some creatures can bite, bite, some can stick stick you, some some sting, some can scrape you, and some can even deliver an electric shock.
Most divers divers are concerned about encountering larger, larger, more aggressiv aggressive e animals animals that that can bite, such such as sharks (figure (figure 8-16) and kille killerr whales. whales. Seeing the these se animals while diving is rare.
F IGI G U R E 8 - 1 6 . O B S E R V I N G S H A R K S I N T H E W I LDL D C A N B E A R A R E A N D A T H R I L L I N G E X P E R I E N C E .
NAUI Scuba Diver
F I G U R E 8 1 7 . B A R R A C U D A S L O O K M E A N , B U T A R E O N L Y C U RIR I O U S.S . HOW EVER, THEY S TILL NEED TO BE TREATED W ITH RESPECT.
Your chance of se seeing eing a large shark that could could injure you is much lower lower than having a tra traffic ffic accident on your way way to the dive site. Because shark attacks occur so infrequently, the media portrays them much much more mo re dramatically dramatically than traffic traffic accidents. Many diver divers s pay substantial substantial amounts amounts of money money to go go on diving trips specific specificall ally y to see sharks, sharks, because because sighting sighting one on an ordinary ordinary dive is so rare rare.. Barracuda Barracuda are large, curious fish with a menacing appearance appearance (figure (figure 8-17 8-17). ). These fish occasio occasionally nally attack divers if they feel cornered. cornered. They can cause cause a pain painfu full bite, but there has never been been a recorded case of a barracud barracuda a injury killing killing a diver. diver. Barracudas Barracudas will fol fol low divers for long periods. periods. Bright Bright,, shiny shiny objects, objects, such as jewelry, attract attract them. them. In most cases, cases, barracuda barracuda will will turn away if you swim directly directly towards towards them. Eels are long, snakelike fish that live live in rocks and crevices (figure (figure 8-18). They have a menacing appear ance and long sharp teeth. teeth. They breathe by opening and closing their mouths mouths to flow water over over their gills gills and might look as iiff they are readying readying to bite you you.. Unless you you stick your hand near or in a hole containing an eel, they will not normally attack attack you you.. Freshwater also contains contains hazards, such as alligators alligators in the southeastern southeastern United States, crocodiles in Afric Africa a and Central America, America, muskrats, snakes, and even snapping snapping turtles. It is rare for a diver to have a negative encounte encounterr with with these animals. In most cases, they avoid divers. divers.
F IGI G U R E 8 - 1 8 . E E L S LO L O O K M E N A C I N G B U T W I LLL L U S U A L L Y O N L Y BITE IF YOU REACH NEAR OR INTO THEIR HOLES.
In salt water, the most most common common form of hazardous marine life life is probably probably the the sea sea urchin urchin (figure 8-19). These are small small creatures covered with sharp spines. spines. They are found in almost e every very ocean. Sea urchins are extremely slow-moving creatures and they do not attack attack divers. Divers are injured injured when they bump into or step on these creatures creatures and impale impale themselves on the spines. You can usuall usually y avoid this type of injur injury y through good good buoyancycontrol. Stingrays Stingrays are one example example of marine marine life life with an external body spine that can cau cause se injur injury y (fig (figure ure 8-20). Most fish fish with defensive spines such as these introduce introduce a toxin toxin into into the wound they make when they respond respond to a threat. Like most of the the other fish with spines, stingrays are docile creatures creatures that spend spend much much of their time time lying lying on the bottom bottom. They will ill attack attack only when the they y are pro pro voked, usual usually ly because a diver diver has stepped stepped on them. The best way to avoid this type type of injur injury y is to look care care full fully y at the bottom bottom before putting your hands or feet feet down and shuffle your feet when walking walking in in the shal shal lows, rather rather than than stepping up up and out. Cone Cone shells are an example of a mollusk mollusk that has a spine and a venom sac. Cone shells eat other mollusks, worms wor ms,, and small fish. They inject inject their prey with a toxin to stun them them and then consume consume them. If a diver picks up a cone shell shell and is injured injured by the spine, they will ill also have the the toxin introduced into the wound. This
Chapter 8- Diving Environment
accidental contact with their stinging cells, which which are located on their tentacles. The tentacles can hang as much as 15meters (50 (50 feet) or more below the jellyfi jellyfish. sh. Most Mo st diving suits will will protect protect you you from the sting of a jel jel lyfish. lyfish. In addition, it is frequently frequently possible to see these creatures from a distance and avoid them. Do not swim beneath them if you see them floating floating on the surface. Marine creatures that can scrape you include corals and barnacles. These These are slow growing animals that injure injure you only if you b bum ump p into them. Proper buoyancy control is your best best avoidance technique.
F IGI G U R E 8 1 3 . S E A U R C H I N S W I LLL L H U R T Y O U O N L Y I F Y O U B U M P I N TO TO T H E M .
•
% '
.
V?-.
«
There are a few s spe pecie cies s of electric fish, including including an electric eel and electric ray, which immobilize their prey by emitting an electric shock. shock. Electri Electric c eels are are found in the Amazon basin in South America. You can find different different species species of electric electric rays throughout the world. Informa Informatio tion n about these creatures would be included in an orientation to a new area.
Review the the following following questions questions about marine marine life: life: 14. True or False: Injuries Injuries from aquatic life are usually the result of an offensive offensive action action by the animal. animal. 15. You should not even if you know what it it is. is. 16. Sea urchi urchins ns are are an example of a ______________________
_____________
F IGI G U R E 8 2 0 . S T I N G R A Y S A R E N O R M A L L Y D O C I LEL E C R E A T U R E S .
17. Jelly Jellyfi fish sh are an example of a can be life-threatening, but you can avoid this this type of injur injury y simply by not picking up such shells.
Je Jellyfi yfish are slimy, gelatin-like creatures that swim by pulsing, or contracting contracting their their bodies bodies.. They feed on small fish fish and other other tiny creatures that float in in the water. There are many different sp specie ecies of jellyfis jellyfish, h, and they are found in most oceans. Jel Jelllyfi yfish are slow moving and do not attack divers. These creatures do cause injuri injuries es through a diver’s diver’s
CONSERVATION As a diver, you can can have a profound effect on the underwate underwaterr world. world. If you are a careful and conscien conscien tious diver, you can help ensure that the reefs reefs where where you dive today will ill be there for your childre children n tomorrow. tomorrow. A careless or uncar uncaring ing diver can can destroy hundred hundreds s of years of coral growth growth in a single dive (figure (figure 8-21).
NAU I Scuba S cuba D iver
t n e m n o r i v n E g n i v i D
F IGI G U R E 8 2 1 . A C A R E L ES E S S D I V ER ER C A N D E S T R O Y H U N D R E D S O F Y E A R S O F C O R A L G R O W T H I N A S I N G L E D I V E . FIGURE 8-22. AVOID TOUC HING COR AL OR OTHER MAR INE
Most divers would not deliberatel Most deliberately y do anything anything to hurt the creatures in the underwater world. If you do not know or understand the delicate natures natures of certain certain fish or animals, animals, it is easy to hurt them.
DIVER IMPACTS As a diver, you have a choice to make make either either a negative or a positive impact impact on the underwater world. When you dive, you wil willl see divers who constantly make make an effort to leave leave only only bubbles where they have been, and take take only pictures. They enjoy the und underwater erwater world and leave no evidence that that they have been there. Occasionally, Occasionally, you will ill seeother divers who leave their mark on the underwater world, world, either either consciously consciously or not.
m
188
When you you first dive on a coral reef, it it can be difficult difficult to imagine that the hard coral structures structures are are actuall actually y thousands thousands of delicate animals animals called called polyps you are are polyps.. If you careless about your buoyancy control, you can can break off pieces pieces of coral coral or rub off its protective coating. It is easy easy to kill ill or injure injure coral coral through carelessn carelessness ess (figure (figure 8-22). 8-22). Silt or sand sand landing landing on top of corals can also be extremely destructive (figu (figure re 8-23). 8-23). The tiny polyps polyps that live withi within n the hard coral structure eat tiny microscopic
CREATURES.
plants and and animals living living in the water. water. If your buoyan buoyan cy control control is is poor poor and you stir up large large clouds of sand sand or silt, any sand or silt that lands on the corals can smother the polyps. You can also dama damage ge animals that live live in in colder waters waters through accidental contact. For example example,, a rare form of red or purple hydrocoral hydrocoral grows at only a few dive sites in California. California. It is extremely extremely beautiful, beautiful, but also delicate and slow growing. It is easy easy to break and you must not handle it. You can easily catch certain certain type types s of fish and other creatures that that are slow moving, and this tempts tempts some divers to handle and examine them, or to hold them while while another another diver photographs them. You must avoid this for several reasons. Most fish have a protective layer layer of slime that that covers their their bod body. y. When this slime is removed oved by human handlin handling, g, it makes makes the the fish vulnera vulnera ble to harmful harmful parasites. parasites. Also, Also, handling handling a fish can dam dam age its internal organs and kill it.
To have a positive effect on the environment, environment, you must develop goodpersonal diving diving skills skills and habits. Strive Strive to perfect your buoyancy control soyou always remain a fewfeet above the reef or bottom. Learn to dive dive
Chapter 8- Diving Environment
i v i n g E n v i r o n m
F IGI G U R E 8 2 4 . K E E P Y O U R G A U G E S A M O O C T O P U S R E G U L A T O R C L IPIP P E D T O Y O U R B U O Y A N C Y C O M P E N S A T O R .
in a slight slight head-down position position to ensure that that you keep your fins fins off the bottom. Make sure that that your gauges and octopus pus regulator regulator are clipped to you yourr buoyancy com pensator to keep them from dragging on the bottom (fi (fig g ure 8-24). If you have the the opportunity opportunity to be pho tographe tographed or videotaped videotaped while diving, analyze the video video or photographs to seehow you can improve improve your ski skills lls or reposition your your gear to keep it closer closer to your your body. Develop Develop an active conservation conservation ethic ethic and awareness awareness of your environment. There are many active conserva tion groups ups around the world, working working to ensure that your underwater world will will not be be destroye estroyed. They do do everything from counting fish to establishing establishing moorings for dive boats so the boats will ill not have to use anchors, which destroy destroy the bottom bottom.. Your instructor instructor wil willl have information on local conservation conservation group groups s in your area. Many dive shops, dive clubs, clubs, and other groups spon sor cleanup activities activities for water areas enjoyed by divers, divers, boaters, and swimmers. Divers can have have a tremendous positive effect when they participa participate te in these cleanups becaus because e they can actu actuall ally y see see the trash and remove remove it. Checkwith your local local dive shop or dive club for cleanups in your area. Many colleges, universities, universities, dive clubs, dive shops, and other group groups offer seminars you can can attend to learn more mo re about the underwater environment and and its preser vation. The more you can leam leam about conservation, the more prepar prepared ed you you will will be to participa participate te in helping helping preserve and improve our underwater underwater world.
e n t
HUNTING If you speak with any diver with with more than 20 years of experie experience, nce, they will probably tell you about about thegood old days, when game game was was plenti plentiful ful and reefs were brim brim ming with life. Sadly, the impact of divers, divers, commercial as well as sport fishermen, and pollutio pollution, n, means many areas are not as healthy healthy as they were were in the past. past. Divers must take responsibility for protecting the world’s world’s underwater resources for generations to come. If you hunt hunt or take game game under water, water, you must be be famil famil iar iar with the fishing regulations in your your area. You must know which which species species you can lega legally lly take, the closed and open open seaso seasons, ns, catch and size limits, limits, legal legal methods thods of take, and any other pertinent pertinent information. information. Divers who violate fishing regulations give all divers a bad name, and they encourage governmen governments ts to write furth further er regula regula tions that affect all diving. Even if the fishing regulations in your area are gen erous, erous, allowing allowing substantial bag limits for a particular species species on any given day, you must resist taking taking more game than you need for your personal personal consumption. consumption. Some Some bag limits exceed exceed what a normal normal individua individuall can use, use, but you certa certainl inly y do not need need to take everything you can get. Most marine species are overus overused, and fishin fishing g regu lations lations in in most areas have not kept pace with the increasin increasing g demands demands placed on them by all all groups. ups. Some areas have serious serious competiti competition on between sport and
189
NAU I Scuba D i ver
/.
•/' /' ■ #i>V
* Va? : *
.
" x r
F IGI G U R E 8 2 8 . C U T O P E N S I X -P- P A C K R I N G S T O A V O IDI D T H E P O S S I B III I F IGI G U R E 8 2 5 . S H I P W R E C K S W O U L D B E E A S I LYL Y D E S T R O Y E D I F EVERY DIVER TOOK A PIECE HOME.
commercial commercial fisherman fisherman for the same species. However, ever, the ultimate losers are the animals animals being caught.
COLLECTING Many thousands thousands of creatures with beau beautifu tifull shells live live under the the sea, in tropic tropical al and in colder waters. waters. Divers can obse observe the these se creatures in th their eir natu natural ral habitats, habitats, soshell collecting collecting is an activity activity enjoyed enjoyed by many divers. divers. Some type type of marine anima animall forms every shell seen seen under under water. water. If you collect shells with living living animals, animals, you are removing removing that anim animal al from the population population and destroying destroying its chances to reproduce. Conscientious Conscientious divers only collect collect empty shells. Check that nothing nothing is living living inside the the shell. shell. It is usually possibl possible e to find a goodspecimen of the shell shell you want witho without ut resorting to collecting a live animal.
E X P L O R IN I N G W R E C KS KS Most divers Most divers enjoy the thr thrililll of exploring exploring a sunken ship, whether a fish fishing ing boat that sank a fewyears ago, a warship sunk sunk during World World War II I I, or a mail mail steamship steamship wrecked during during the 1800s. Litt Little le can can compete with with the excitement of findi finding ng a new, unexplored wreck. wreck.
! T Y O F A M A R I N E M A M M A L O R B IRI R D B E C O M I N G TRAPPED IN THE RINGS.
Many divers like to collect artifacts from from shipwre shipwrecks cks to decorate decorate their homes. Unfortunatel Unfortunately, y, when you do this, you generally generally destroy part of the wreck to remove remove the item from it (figure (figure 8-25). 8-25). This takes away from the histor historica icall value and atmosphere atmosphere of the wreck. If enough people people remove artifacts, artifacts, the wreck wreck wil willl be reduced reduced to a pile pile of rubble on the sea sea floor. Remember that that wrecks can be the property of the origina originall owners, ers, or of the group roup salvaging it. In many areas, removing artifacts artifacts from shipwrecks shipwrecks is illeg illegal al and violators violators can lose all of their dive gear and face severe vere fines. Divers Divers have receiv received ed stiff fines for re removing moving arti facts in marine marine parks or state-controlled state-controlled waters. waters.
C L E A N INI N G U P T H E E N V I R O N M E N T Many types of trash can be harmf harmful ul to marine crea tures, so you must not dump trash overboard overboard when div ing from a boat or carelessly carelessly discard it it at the beach. beach. Synthetic materials materials such as plastics can last for years in the marine marine environment environment and harm numerous animals. If you buy soft soft drinks in six-packs six-packs with plasti plastic c rings holding holding the package package together, together, you should should cut these rings open open before before you discard them - even even into into trash trash recepta cles (figur (figure e 8-26 8-26). ). This helps avoid the possibili possibility ty of a marine mammal or bird becoming entangled entangled in them them if the plastic plastic is is lost. Recycle these rings whenever whenever possible.
□
Chapter 8- Diving Environment
□
Plastic Plastic trash bags ags are especially harmful harmful to sea sea tur tles. These These animals animals regula regularly rly feed on jellyf jellyfish ish as part of their their diet, and a plastic plastic bag floati floating ng in the ocean resem resem bles bles a jellyfish jellyfish closely enough enough that a sea turtle wil willl eat it. Obviously, turtle turtles s cannot digest these bags. The bags block their their digestive systems and kil killl the turtles. You should dispo dispose se of trash properl properly y and recycle it when possible. possible. Looking at at trash under water is not a fun part of diving.
Review the followi following ng questions questions about conservation: 18. or can damage coral. 19. You should only collect collect shells that that are ______________
20.
_________________
mistake mistake plastic trash bags as jellyfish.
F I G U R E 8 - 2 7 . B O A T D IVIV I N G R E Q U I R E S S P E C I A L P R O C E D U R E S .
Many of the bes bestt diving diving sites in the world are in remote locations locations and can be reached reached only by boat. boat. To enjoy this experience, experience, you must learn learn the proper proce proce dures dures for diving from boats boats.. Boat diving diving requires unique skills skills whether you you dive from a smal smalll or large large vessel. It is important to becom become familia familiarr with the proce proce dures for diving diving from a charter charter boat. Go with an experi enced enced diver or group to learn the correct techniques. You must must know how to enter, exit, get get your cylind cylinder er filled, filled, keep your gear together, together, and all all of the other pro cedures cedures used used for boat diving diving in your your area area (figur (figure e 8-27). 8-27). Commercial charter charter boats depart depart at a set time, so plan to arrive at least 30 minutes before before its departure time. Sign in when you board board the boat boat and stow stow your gear as directed by the crew. Tour Tour the vessel and ask quest question ions s to familiariz familiarize e yourself with its layout. Diving from a small boat require requires s that you learn learn yet another set of procedures. Because of space limitatio limitations ns created by the size of the boat, you must lear learn n how to manage your gear in as small small an area area as possible. possible. For
example, you mig might ht need to assem assemble ble your scuba un unit it and don your divin diving g suit on shore, board the boat, boat, and ride out to the site. Procedures Procedures for entering and exiting exiting the water vary depending on the size and configur configurati ation on of the vessel. ssel. On a small small boat, care might might be required to keep keep the boat balanced as as you enter enter or exit it. In this situation, it it is often helpful helpful to don and remove your scuba equipment in the water water rather rather than aboard the the small boat. Some means to to get back in the boat must must also be availab available. le. Additional Additional safety procedures are also necessary for small boat diving. A written plan of your destination destination and your expected expected time of return must be left with □ someone on shore so they can can summon help help if if you do not return within a reasonable time. This plan is called a floa t plan. Good seamanship seamanship is important, important, and more more than one person aboard any boat boat must be be trained trained to operate m it competently. Be sure to to take a sanctioned course in small boat handling handling if if you plan regular regular dives dives from small boats.
NAU I Scuba D i ver
t n e m n o r i v n E g n i v i D
m
When you reach reach your dive site, site, you must set the anchor. anchor. After the anchor is set, it must be be checked at the beginning of the dive to make make sure it is secure. secure. At the the end, the anchor must be clear clear for lifting lifting.. For complete complete security, security, someone who can operate the boat should remain on board at all all times. Whether you dive from a large large or small small boat, you must must remain near the vessel vessel and upcurrent from it dur ing your dive. dive. A trail trail line with with a float float exten extended ded behind behind the boat boat is essential when even even the possibility possibility of a cur cur rent exists. Diving Diving properly from boats boats requires traini training ng and diving diving with an an experien experienced ced boat diver. This is particu particu larl larly y true for specialized activities activities from boats, boats, such as as drift drift diving. diving. Learning Learning about diving diving from someone more experienced experienced helps helps to greatly greatly reduce reduce the risk risk of embar rassment, rassment, frustrati frustration, on, and unpleasant unpleasant incidents.
Visibil Visibility ity in Califor California nia can can range from 3 meters eters (10 feet) feet) along along the beaches beaches to over 30meters (100 feet) at the islands. The average average visib visibilility ity is is from 10 to 15 meters (30 to 50 feet). feet). The water water temperature ranges from a low low of 10°C (50° (5 0°F) F) in the winter to to a high of 21°C (70 (70°F) °F) in the late sum summe merr and and early fall. The The average average water tempe temperature rature is 17°C (62° (62° F). F).
POPULAR DIVING AREAS After After you you complete complete your NAUI Scuba Diver certifica certifica tion course, you wi willll be able to dive dive on your own under simila larr to those in which which you did your open conditions simi water dives. dives. If you are like most most divers, you you will will want to travel travel to other areas and experience new and different dive sites sites.. Following Following are descriptions of som some different locales to give you an idea of of the the variety variety of diving diving you can find throughout the world.
Californ California ia is one of the the most most popular diving areas areas in the world. With With its mild year-round surface tempera tures and goo good water conditions, conditions, diving diving is a favorite favorite sport with many people in this part part of the United States. Most diving in Califor California nia is concentrated concentrated among among the giant giant kelp beds found offshore al along ong the coast and nearby islands islands (fi (figur gure e 8-28). These kelp beds are home to nume numerous rous animals and fish, includi including ng sea lions and seals, seals, many species species of rockfish, lobsters, lobsters, scallops, and thousands thousands of other creatures. Diving Diving in a kelp bed is like swimming through through a forest forest,, with light light filter filtering ing down from the surface tthrough hrough the long long kelp stalks.
192
F I G U R E 8 2 8 . K E L P B E D S P R O V I D E f t B E A U T I F U L D IVI V I N G ENVIRONMENT.
Chapter 8- Diving Environment
Cozumel is located in the western Caribbean Sea close to the Yucatan Yucatan peninsul peninsula a in Mexico. The island is bordered by the world’s world’s second second largest liv livin ing g coral coral reef systemthat extends south past Belize to the Bay Bay Islands Islands of Honduras. Drift Drift diving, or swimming along with the current, is the way to enjoy the scenery scenery of the Cozumel Cozumel reef. reef. Divers allow the current current to mo move ve them along as their boat follows them them by watching watching for their their bubbles. bubbles. The reefs reefs are covered covered with colorful colorful corals corals and sponges and are inhabited inhabited by a variety of tropical tropical fish, as well as crabs, lobsters, eels, and grouper. The air temperat temperature ure ranges ranges from 21°C (70 (70°F) °F) in in the winter to to 32°C (9 (90°F) °F) in the summe summer. r. The water temperat temperature ure rang ranges from 25°C (78 (78°F) °F) in the winter to 31°C (88 (88°F) °F) in the summer. mer. The visibi visibility lity is in exc excess of 30meters (100 feet) feet)..
The Louisia Louisiana na and Texas coasts coasts on the the Gulf Gulf of Mexico offer diving diving at offshore oil platforms. platforms. These plat plat forms forms are located far from shore, shore, so diving diving is norm normall ally y done from a boat. The platforms platforms are artifi artifici cial al reefs reefs,, attracting attracting many different kinds of fish and other animals animals that that live live on the structure. structure. You can see giant groupers weighi weighing ng over 45 kilograms (100 (100 pounds) at many of these sit sites. es. Visib Visibili ility ty at the platforms is good most of the year and ranges from from 10meters (30 (30 feet) feet) to 45 meters (150 feet). feet). The water temperature temperature in the summer summer varies from approximately 21°C (70°F) to 27°C (80°F).
The Great Lakes Lakes of the central central United United States offer some of the finest freshwater diving in in the world. There are numerous numerous shipwrecks shipwrecks located located in these these waters, waters, many many of which are relatively relatively intact intact becaus because there is no salt salt to cause corrosion and no marine creatures that that attack wood. Some of the wrecks in the Great Lakes are are hun hun dreds of of years old, yet yet still still in excellent excellent condition. condition. Visibi Visibility lity in the Great Lakes Lakes can be very good, and
can exceed 15 meters (50 feet) feet) at some of the better dive spot spots. s. Mo Most st of the wrecks wrecks are covered with with fine fine layers of silt that are easily s stirre tirred d up, up, limiting limiting visibility visibility.. These ese waters are quite cold, even during the summer months, months, and most divers wear dry suits. The lakes’ lakes’ great size allows allows ocean-lik ocean-like e waves and storms to develop.
The Turks Turks & Caicos Islands are located in the British British West Indies of tthe he Caribbean Caribbean Sea. The islands have coral coral walls, walls, ledges, and drop-offs with plenty plenty of underwater life (figur (figure e 8-29). 8-29). Divers encounter reef fish, sea turtles, barracuda, barracuda, eagle rays, and several species of sharks. Wrecked Spanish Spanish galleons and other ships ships are available to be explored. The visib visibilility ity ranges from 30 meters (100 feet) to 60 meters meters (200 feet) and the average water temperature is 27°C (80°F).
Coral reefs reefs surround Truk Truk Lagoon, which which is the per per manent resting place of over 60 ships ships and 250planes sunk sunk during during World War II. II. Truk is located located in the South South Pacif Pacific, ic, with with Palau Palau to the west and and the the Fiji Fiji islands to the the southeast. southeast. Some of the the creatures found in Truk includ include e angelfish, tangs, tangs, lionfish lionfish,, triggerfish, and clownfish as as well as rays, moray eels, eels, tuna, and turtles.
S UR U R E 8 2 9 . T R O P I C A L L O C A T I O N S A F F O R D O P P O R T U N I T IEI E S T O OIVE CORAL W ALLS, LEDGES, CHAN NELS AND OVER HANGS TEEMING WITH EXOTIC MARINE LIFE
NAU I Scuba Sc uba D i ver
The average water temperature temperature in Truk Truk is 28°C 28°C to 29°C (82 (82°F to 84°F 84°F)) and the visib visibilit ility y can be be up to 30 meters (100 feet). feet). t n e m n o r i v n E g n i v i D
194
The Galapagos Islands Islands are located 600 miles west of Ecuador in the Pacif Pacific ic Ocean. Ocean. The islands are are an Ecuadorian Ecuadorian National Park Park and marine pres preserv erve. e. The islands are best known as the inspira inspiration tion for Charles Darwin’s Darwin’s theory of evolution. evolution. The islands are on the Equator, Equator, but the the Humboldt Current, which originates originates in Antarctica, brings c cool, ool, nutrient-rich water north. north. The The mixture of warm currents from Central Central America with the Humboldt Current has allowed the islands islands to produce an amazing array of sea life aswell as birds and wildlife wildlife on the islands. The Galapagos islands are the home home of sea lions, lions, penguins, eagle rays, and schooling hammerhead sharks. Strong currents are a hazard in this area.
otes
CHAPTER
NAU I Scuba Diver
LEARNING GOALS In this chapter you will: • Be introduced to some special special interests you can develop in diving diving and howyou can meet meet other divers with those interests. • Learn Learn about some of the courses you can can take to continue your diving education. By now, now, you have have received (or ne nearl arly y received) the knowled knowledge, ge, skills, skills, and experience that wil willl allo allow w you to enjoy scuba scuba diving on your ow own. n. Soon you will will earn the NAUI certification certification card that will will be your passport ssport to to the underwater world. It has taken study and physical physical effort to develop evelop the nee neede ded d abilit ability. y. You can be proud of all all you have accomplished. accomplished. Now it is time time to look ahead. ahead.
GETTING INVOLVED IN CLVBS
ED
Get involved with other divers divers right away. Local dive clubs are an excellent source for diving diving compan ions, information about the the local local area, and introduc tions to many diving activit activities. ies. Be sure sure to ask about about jo joining a dive club in your area (f (figure 9-1).
F U R T H E R I N G Y O U R E D U C A T IOI O N The best best way to remain remain involved involved in diving diving after this course course is to continue your diving education. By com pleting the NAUI S Scuba cuba Diver certificatio certification n course, course, you will be prepared prepared to to dive in conditions sim simila ilarr to thos those e in which which you were trained. There are many other aspe aspects cts of diving you will will need need to learn or further develop develop.. You must must consi consider der your initia initiall certification certification as alicense to learn how to dive. dive. Experience and and additional training training are needed needed for you to dive under other conditions. The field of diving is always always changing. Equipment is const constant antly ly being being improved and new types developed. Discoveries even change our understanding of the effects of pressure pressure on on divers. Therefore, continui continuing ng education is important. You should subscribe to diving diving magazines, magazines, attend diving diving seminars and conferences, such as NAUI Worldwide’s International Conference on Underwater Educatio Education, n, take refresher courses everyyear or two, and obtain the the highest highest level of certificatio certification n possib possible. le. All will will help to keep your your knowledge current. current.
SPECIALTY COURSES To further your diving education, education, you can leam div ing specialties by taking a NAUI-sanctioned NAUI-sanctioned Specialty Course. A few of the many specialty specialty courses availa availabl ble e are Night Diver, Rescue Diver, Cavern Diver, or Underwater Photographer (figur (figure e 9-2). While While experience experience is a good teacher, it frequently frequently givesyou the test before before the lesson. lesson. This results in frus frustrati tration on and wasted wasted time. It can also be unsafe. To get the most from a diving diving specialty, specialty, and to get it quickly quickly in in today’s fastfast-pac paced world, complete a NAUI Specialty Specialty Course. This way, you will ill quickly quickly achieve suc suc cess and be able to take advantage of your your NAUI instr instruc uc tor’s years of exper experience ience in your area of interest. interest.
T H E A D V A N C E D S C U B A D IV E R C O U R S E The Advanced Advanced Scuba Diver course introduces you F I G U R E 9-1. DIVE C L U B S O F F E R N E W G IVI V INI N G C O M P A N I O N S A N D INFORMATION A B O U T D I V I N G A C T I V I T I E S .
to a variety variety of diving activities. activities. It is desig designedf o r newly certified divers who desi desire re additional additional training training and an
F I G U R E 9 -2- 2 . N A U I S P E C I A L T Y D I V I N G C O U R S E S A R E A G O O D W A Y T O L E A R N N E W A C T I V ITI T I ES E S T H A T W I LLL L E X P A N D Y O U R DIVING EXPERIENCES. F IGI G U R E 9 3 . T H E N A U I M A S T E R S C U B A D IVI V E R C O U R S E W I L L T E A C H
orientation to a variety variety of diving sites sites and conditions. conditions. The types of dives dives include navig navigatio ation, n, deep, ep, and night night or limited visibil visibility ity diving diving as well as instructor-sp instructor-specified ecified dives. dives. The instructor-specified dives can include include light light salvage, underwater mapping, shore shore diving, diving, or or boat boat diving as well as many other activities.
T H E M A S T E R S C U B A D I V ER ER C O U R S E After you have completed the NAUI Advanced Scuba Diver course and several specialty specialty courses, courses, you should take the NAUI Master Scuba Diver Diver course. course. You need need not be an expert diver to take this course, course, but you should have the desire desire to learn learn skills skills that are more more advanced (figure (figure 9-3). This course course provides provides you with eight eight addi tional tional supervised dives where you learn new, useful skills. skills. It also adds to your knowledge knowledge and introduces introduces you to various various specialty areas. areas. Underwater navigatio navigation, n, limited-visibility limited-visibility or night div diving, ing, search and reco recovery, very, light light salvage techniques, and deep-diving deep-diving procedures procedures are included included in the course. course. Every Every diver should complete complete a NAUI Master Scuba
Y O U M A N Y A D V A N C E D S K I L L S .
Diver course. course. At this level, you w wililll have the knowledg knowledge, e, skills, and ability ability to enjoy diving in a variety of condi tions and locations.
TRAINING ASSISTANT SPECIALTY COURSE You can also gain certification certification as a NAUI Trainin Training g Assistant. A NAUI Trai Trainin ning g Assistant Assistant helps helps other divers during traini training ng activities activities supervis supervised ed by a NAUI instruc instruc tor. Helping Helping other divers can include actin acting g as an escort on an underwater tour or assisting a tired diver. To enter the NAUI Tra Train ining ing Assistant course, you must must be certified certified as a NAUI Advance Advanced d Scuba Diver Diver and as a NAUI Scuba Rescue Diver.
LEADERSHIP COURSES Perhaps you will will want to get involved in a leader ship role in diving. diving. Once you have completed completed the Master Master
NAU I Scuba S cuba D i ver
FIGURE 9-4. NAUI LEADERS TEACH DIVING ll\l LOCATIONS ALL OVER THE W ORLD.
Scuba Diver Diver and Scuba Rescue Diver courses, you can strive for the NAUI Assistant Assistant Instruct Instructor or or Divemaster rat ings. For this, you will will needexperience and at least 25 logged dives. dives. Ask Ask your instruct instructor or about leadership trai train n ing opportunities. It is rewarding to help others others realize the dream of becoming a diver or having having an underwater adventure. NAUI has the finest leadership programs programs and and traini training ng available. If you find that diving becomes more than a hobby toyou, rememb remember that through NAUI there there are many opportunities opportunities to work as a professional. By becom ing a NAUI Assistant Assistant Instructor, Divemaster, or Instructor, Instructor, you can profit from from your diving ability, ability, training, training, and experience experience (figure (figure 9-4). Your instructor instructor is an example of this, and will will be glad to to provide you with informa information tion about NAUI Worldwide leadership train training ing programs. programs.
D E V E L O P IN IN G S P E C I A L I N T E R E S T S Donning scuba equipment and exploring the world beneath the surface surface of the water is exciting. You will ill quickly find that diving is simply a means means that allows you to do something something in the underwater world rather rather than being an end end in itself. Soon, Soon, you will want to inspect old wrecks, take pictures, take game, collec collectt things, study aquat aquatic ic ecosystem systems, or dive in unusual unusual places (figure 9-5 9-5). ). Such challenges make diving excit ing and rewarding. Remember that specialty specialty areas can
F I G U R E 0 -5- 5 . I T I S M O R E F U N T O D E V E L O P A S P E C I A L INI N T E R E S T A R E A I N D I V I N G . O N E E X A M P L E IS M A R I N E IDENTIFICATION.
be learned much much more quickly and easily through train train ing than by trial trial and error. One One reason you should get involved with with local local divers is to leam leam about the special divin diving g interests in your area area and to be introduced to them. When you have an underwater objective, your enthusiasm for diving multiplies multiplies many many times over, over, and you you will will have some of the best est times of your life life developing developing and refining refining your interest area. Little Little compares pares with the feeling of accomplishing a goal in the underwaterworld, whether it be taking a per fect photog photograph raph of a rare fish, finding finding an ancient ancient wreck, wreck, or exploring exploring a site where no diver diver has been befor before. e. Imagine the excitement excitement and satisfaction you can experi ence. ence. Realize that relative relatively ly fewpeople people learn how to
Chapter 9- Diving Activities
dive and will ill ever feel the exhilarat exhilaration ion you experience experience becaus because of your success in inner inner space. Learn about the special activities activities of diving diving and get get involved.
'
e m
a r e s p o n s i b l e diver
When you are certified certified as a NAUI diver, you wi willll continue to learn learn through your divin diving g experienc experiences. es. . During During these experiences, you should should remember that that IL T J you have certain responsibilities to yourself, your budd buddy, y, and others. The following is a partia partiall list list of what is expected of you as a NAUI diver: • Keepyourself mentally and physically physically fit for diving. • Continue Continue your diving education. education. • Use Use complete, complete, correct, and well-maintained well-maintained equipment. • Know your your dive site, site, and avoid avoid or abort diving in hazardous conditions. • Be prepared prepared to handle emergen emergencies. • Always Always dive with a budd buddy, y, and remain remain together while diving. • Avoid running low on air, control your buoyancy buoyancy at all all times, times, and ascend properly. • Keep conservation in mind regarding regarding the the environment. • Demonstrate onstrate proper etiquette etiquette toward boaters, fish fish ermen, ermen, and the public. public. It is now time time to look ahead to fun, adventure, and all the excitement you envisioned when you you started this course. course. That strange, wonderful wonderful world of inner inner space is final finally ly accessibl accessible e and waiting for you to to ente enter. r. Enjoy yourself, yourself, and fulfi fulfillll your responsibilities as a NAUI diver. Your instructor instructor looks forward to working with you a again gain soon in your your next NAUI course.
v i n g A c t i v i t i e s
201
NA UI Scuba D i ver
A P P E N D I X A A N S W E R S T O R E V I E W Q U E S T I O N S
11. Capillary. 12. Submersi Submersible ble pressure gauge.
Instrumentation 13. Computer. Computer.
CHAPTER 1 H e a l l b a n d Fitness 1. You must be sound in mind mind and and body to dive. 2. They are not feelin feeling g well. 3. False. False. 4. Dive regularly. regularly. 5. Medicati Medication on only only masks the symptom symptoms of your illness, illness, it does does not cure the illness. illness. The illness will ill affect your physiology u underwater nderwater and could be hazardous.
14. Able to withstand withstand pressure, elapsed time. 15. Rinsin Rinsing g after after each diving day, having having them serviced once per year.
Buoyancy Compensators 16. Jacket Jacket style, back flot flotati ation, on, and horse horse collars. 17. Overinflation valve, oral inflator. 18. To remove salt cr crystal ystals s and to prevent damage to the inside of the BC.
Weight Belts 19. Quic Quick k release.
CHAPTER 2 B a s ic E q u i p m e n t 1. Comfort and fit. fit. 2. A, purge valve. valve. 3. Length Length of the tube, tube, inside inside diameter diameter of the tube, sharp bends.
20. Compensates for the compression compression of a wetsuit wetsuit at depth. 21. They are more comfortable, comfortable, less less likely likely to cause damage if if dropped.
Diving Suits 22. Skin Skin suit.
Cylinders 4. A “J ” valve has a res reserv erve lever and and a “K” “ K” valve does not. 5. Aluminum, Aluminum, steel. 6. Visual Visual inspection inspection each year, hydrostatic test test every 5years.
23. Wetsuit. Wetsuit. 24. Dry suit. suit. 25. False. False.
A c c e s s o r y E q u i p m e n t 26. To cut line line underwater. 27. Dive near the flag, only display display the flag flag when when
R e g u l a tot o r s , A l tet e r n a t e A i r S o u r c e s , a n d Instrumentation 7. Ease of breathing. 8. Dust cap. 9. Convenience, low price, integrated integrated system. 10. Completely independent air supply.
divers are in in the water. 28. You might might be required required to provide proof of expe rience, documentation documentation of experience experience for leader ship training.
2 9 . Slate, goodie bag, underwater light, light, marker buoy, spare parts kit, checklists.
Appendix A
CHAPTER 3 U s ini n g M a s k , S n o r k e l , a n d F ini n s 1. Backward. Backward. 2. Use your buddy or wall wall for support, sit sit down. 3. Blast, displacement. 4. Displacement. Displacement.
A s s e m b l i n g S c u b a G e a r 5. So the inlet inlet to the the first stage of the regulator regulator lines up with the outlet from the cylinder valve. 6. Counterclockwise. Counterclockwise. 7. Undo any clips clips on the front of the BC and the waistband; lift lift your your unit unit as a buddy team; make sure you you have your regulator, regulator, octopus, octopus, and gauges out of the way when you fasten your waistband and clips clips;; let your buddy buddy knowwhen you have the waistband fastened and can can sup port the weight of the cylin cylinder der yourself. 8. After you don your your scuba unit. unit.
E n t r i e s end Exits 9. Buoyancy Buoyancy compensator, pensator, air air supply, regulator, regulator, octopus, weight weight belt. 10. BC should be part partia ially lly inflated inflated to provide provide buoy ancy, ancy, hold your mask firmly firmly in place to avoid flooding it it or having having it come off, breathe from your regulator regulator during during the entry, make s sure ure that the the entry area belowyou is clear clear and sufficiently sufficiently deep for the type of entry you are using. using. 11. Get yourself yourself into the water with minim minimal al effort and effect on you and your equipment. equipment. 12. A. Distance Distance to the water is is several feet. B. Low, unstable platform platform or small boat. C. Able to sit at the edge of the water.
Mask Skills 13. Orient Orient your mask so that the inside inside of of the mask is facing facing you and your snorkel is on the left left side, place the mask strap on the back of your head and position position the mask over your eyes and nose,
pull pull the mask mask away from your forehead and make make sure sure that all all of your hair or your hood is out of the mask, mask, inha inhale le a breath of air, air, put the heel of your your hand to the top of the mask frame and push in, start exhaling exhaling through through your nose nose as you tip your head back. back. 14. Toward the bottom.
Regulator Shills 15. Blow tin tiny y bubbles. 16. Blas Blast, t, purge. 17. Hold Hold the mouthpiece loosely in in your your mouth.
Buoyancy 18. Exchange Exchange your snorkel for your your regulator regulator,, note the exact time tha thatt your head leaves leaves the surface, deflate your BC, equalize your ears before you you start your descent descent,, exhale and begin your your feetfirst first descen descent. 19. Maint Maintai ain n eye contact with with your buddy, buddy, equalize equalize your air air spaces often, control buoyancy, control rate of descent. 20. Sign Signal al buddy, agree to ascend, look up, reach up, swim up, up, control control buoyancy, ascend no faster faster than 9 meters meters (30 feet) per minute. 21. Amount Amount of weight you wear, amount of air air in your BC, amount of air in your lungs, objects you are carrying, carrying, type type of diving diving suit you are wearing, amount o off air in your cylinder. 22. Vent the air. air.
Safety Shills 23. Two. 24. You and your your buddy should should agree on which which regulator regulator w wililll be used used before the dive. 25. Prac Practice tice before before the dive and again at the very beginning of of the dive while while on the surface. 26. When no source source of air is avail availab able le and you you are deeper than than 40 feet.
NAU I Scuba Sc uba D i ver
B u d d y S y s tet e m 27. Discuss the dive before you get in the water and agree agree on the location, location, purpose, purpose, activity activity,, and general course course you will ill follow follow underwater; underwater; mainta maintain in your same position relative to each other other for your entire dive; establish your direc tion of travel underwater and then follow that heading unti untill you or your buddy suggest a change change with a clear signal. 28. Get Get yourself vertica verticall in the water and do do a slow 360° turn looking for your buddy buddy or their bub bles, rise about three meters (10 feet) in the water and do another 360° turn turn looking looking for your buddy or their their bubbles, bubbles, ascend slowly to the surface after a minute if you do not see your buddy, buddy, surface, note your position position relat relative ive to two points on the shore, and wait for your buddy, when your buddy surfaces, get back together and continue continue your dive, dive, signal for help if your buddy does not surface.
CHAPTER 4 Density and Its Eflects 1. 20.9%, nitrogen. nitrogen. 2. False. False. 3. False. 4. Streamlining. 5. Larger, Larger, closer. closer. 6. False. False.
Buoyancy 7. Weight Weight of your body, the weight of your gear (diving (diving suit, weight weight belt, and scuba scuba unit) unit),, body size, size, the thickness of your diving diving suit, suit, and the volume of your gear. gear. 8. Change Change amount of weight worn, change amount of air in BC, change change amount amount of air in lungs. 9. Decrease.
Communication 29. Hand signals, slate, rapping, or touch. 30. Visual signals signals or audible audible signals. 31. Answe Answer it with with a disti distinct nct hand signal. signal. 32. Signal Signals s must be discussed and agreed upon before the dive.
H a n d l ini n g S c u b a E q u i p m e n t ini n tht h e W a t e r 33- You want to be positiv positively ely buoyant buoyant at the surface surface and negatively negatively buoyant at the bottom. 34. Keeping the hose inside inside your arms. 35. Hold Hold the belt belt by the free end, keep your your body between the belt and the bottom.
36. Ripple Ripple marks, sun and shadows, surge, landmarks. landmarks. 37. Align Align the compass with with your your body, keep the compass level, level, sight sight across the compass. 38. A heading 180° from your origin original al heading (the opposite direction direction from from which which you started). started).
10. Decrease. Decrease.
Pressure 11.10.3 meters (34 feet), feet), 10 meters (33 feet). feet). 12. 5 times. times. 13.3 atm.
A i r Q u a n t i t y i n B a l l n n n P ressu re
Volume
Density
Doubles
Halves
Doubles
Triples
One third
Triples
Halves
Doubles
Halves
Quadruples
One fourth
Quadruples
A i r C o n s u m p t i o n 14. Depth, physical physical activi activity, ty, physica physicall size, mental state, warmth of diving suit. 15. Submers Submersible ible pressure gauge.
Appendix A
Squeezes and Blocks 16. Ears, Ears, sinuses, lungs, iintestines, ntestines, teeth. teeth. 17. Diffi Difficu cult lt or impossible to equalize pressure pressure in your sinuses. 18. Exhale Exhale through your your nose nose into your your mask. 19. Squeeze. Squeeze. 20. Vertigo, ruptured ear drum, hearing hearing loss. 21. Swoll Swollen en or or congested sinuses. 22. Mask squeeze. 23. Block Block or reverse block.
3. Six meters (20 feet). feet). 4. In excess cess of of normal nitrogen that remains in your body after a dive.
Dive Table Buies 5.9 5.9 meters meters (30 feet). feet). 6.10 minutes, minutes, 1hour. hour. 7.18 7.18 meters (60 feet)/30 minutes 15 meters (50 feet)/20 feet)/20 minutes minutes 9 meters meters (30 feet)/40 feet)/40 minutes. 8.12 8.12 meters (40 feet)/40 minutes.
L u n g s a n d B r e a t h ini n g 24. Holding your breath, breath, not breathin breathing g properly. 25. Normal. Normal. 26. Carbon dioxide. dioxide. 27. Slowly, Slowly, deeply. 28. Keep the mouthpiece outhpiece in your your mouth.
indirect Effects ot Pressure 29. Have Have cylinders fill filled ed with with compresse pressed d air air only. 30. Have cylinders cylinders filled filled at a reputable air air station. 31. Dive within within your your depth and time limits limits,, ascend slowly. 32. Dive at at shallo shallow w depths. 33. Ascend a few feet to reli relieve eve the symptoms.
T h e r m a l E fff f e c t s o f D i v ini n g 34. Conducting heat away from your body, com pressed air to to your body temperature. temperature. 35. The air air cools. 36. Surface Surface tension. 37. Prevent Prevent dehydration. 38. True. True.
Table 1 9. H.
10. 1. 11. D.
Table 2 12. E. E. 13. B. 14. F.
Table 3 15. 31 minut minutes. es. 16.18 minutes. 17. False. False. 18. 30 minutes minutes.. 19. 73 minutes. minutes. 20. 37 minute minutes. s. 21.42 minutes.
Dive Planning Worksheet 22. See Figure Figure A-l. 23. See Figur Figure e A-2.
CHAPTER 5 Ingassins and Outgassing 1. Ingasses, Ingasses, equilibriu equilibrium. m. 2. Relieve Relieve pressure by by ascending too fast.
Dive Computers 24. Ascend. 25.30 meters (100 feet). feet). 26. Initi Initiali aliza zatio tion n sequence.
NA UI Scuba Diver
27. Scrolling. 28. Decompression sickness. sickness. 29. Flashi Flashing, ng, beeping.
S a m p lel e P r o b l e m s 1. See Figur Figure e A-3. 2. See Figu Figure re A-4. 3. See Figu Figure re A-5. 4. See Figu Figure re A-6. 5. See Figur Figure e A-7.
Conducting Your Dive 10. Site survey, emergency plan, plan, activi activity. ty. 11. Whether Whether it is safe to dive dive at the site. 12. When When to change course, course, when to begin begin the return return leg, and when to surface. 13. Five Five minutes. minutes. 14. Wor Workin king. g. 15. Depth, Depth, time, remaini remaining ng air air supply.
D i v i n g Y o u r Plan 16. Confusion. Confusion. 17. Challenge, Challenge, rewarding. rewarding.
CHAPTER 6 Long-Range Planning 1. a. a. Plan Plan the objective. b. Select your location. c. Determine the date and time. d. Make travel arrangements. e. Determine Determine equipment equipment needs. f. Determine if you ne need ed a refresher. refresher. 2. Months. Months. 3. Two weeks.
Short-Range Planning 4. Air fills fills for for your scuba scuba cylinders, film, sun screen, screen, seasicknes seasickness s medication, fish fishing ing license, license, light light sticks for night d diving, iving, defog defog for your mask, spare parts. 5. They can summon help if you do not return at the scheduled time. 6. Weather trends, water conditions, tides, long range weather forecast.
Preparing to Dive 7. Mask, fins, booties, booties, diving diving suit, suit, knife. knife. 8. Regulator, Regulator, buoyancy compensator. pensator. 9 . Twelve hours.
Contingency Planning 18. Alternate site, alternate alternate activity. activity. 19. Alternate Alternate exit exit point.
Recording Your Dive 20. Dive number, date, air air temperature, temperature, water tem perature, perature, visibility visibility,, starting air air supply, supply, ending air supply, average depth, deepest depth. 21. Keep track of your total hours of bottom tim time. e. 22. Diving Diving suit and the amount ofweight you were were wearing, whether you liked liked the site, what you saw.
CHAPTER 7 D ivi v inin g S i M l o n s 1. Rewarm Rewarm yourself yourself by ending your dive dive and get ting out of the water, water, getting into warm, dry clothi clothing ng as soon soon as possible, drink drinking ing warm drinks, taking a warm (not (not hot) bath, if if not not excessively excessively chilled. chilled. 2. Get out out of your exposure suit suit and and get wet to start cooling down down,, drink drink cool water to rehy drate your body, stay out of the sun and rest. 3. Stretch Stretch and massage cramped muscle, proceed slowly with different kick after recovery recovery.. 4. Determine where you are caught caught and try try to get get
Appendix A
clear clear by reversing reversing direction or si sinking, nking, remove remove scuba unit, unit, cuttin cutting g yourself free as a last resort. resort. 5. Hold onto a solid object or hug yourself until until the dizziness dizziness passes. 6. Disconnect inflato inflatorr hose, and vent BC or suit. 7. Stay out of the cabin or any enclosed space space on the boat, get into fresh air, air, settle yourself in a stable spot on the boat, look look at the horizon. horizon. 8. Keep mouthpiece mouthpiece in place and swallow several times in rapid rapid succession. succession. 9. Stop all all activit activity, y, rest, rest, and breathe deeply. deeply.
CHAPTER 8 P h y s i c a l C h a r a c t e r i s tit i c s o l a S i tet e 1. NAUI leader (NAU (NAUII Instruc Instructor tor or NAUI Divemaster), Divemaster), experienced experienced diver. 2. Cave Cave diving, cavern cavern diving, penetration penetration wreck wreck diving, ice diving. 3. Artificial reef, oil rig, breakwater, jetty, ship wreck. 4. Submarine Submarine canyons with sheer drop-offs, lakes, lakes, rivers, caves, caves, coral coral and rock reefs. 5. Mud, silt, clay, clay, sand, pebble pebbles, s, rocks, coral. coral. 6. Shoreline.
A s s i s t i n g O l d e r D i v e r s 10. Help to keep keep problems from occurr occurring ing,, help your buddy overcome overcome any problems that do occur. occur. 11. Surface. Surface. 12. Establis Establishing hing buoyancy, resting and breathing, providing assistance.
Rescues 13. Unconscious and possibly not breathing. 14. First aid, cardiopulmonary resuscitation resuscitation (C (CPR), PR), diving diving rescue rescue,, life life saving. 15. Establi Establish sh buoyancy for for yourself. 16. Get them to the s surfa urface. ce. 17. Keeping the victim victim’s ’s airway dry, mai mainta ntaini ining ng the breathing cycle. 18. Get them to shore quick quickly ly where CPR CPR can be administered and medical assistance assistance obtained.
Emergencies and First Aid 19. Training, Training, equipment, equipment, contact information, information, determination determination to take take action. 20. Update Update training training periodically periodically,, practice practice frequently. 21. First First aid kit, oxygen oxygen kit, blanket, supply of clean freshwater. 22. Divers Alert Network (DAN) (DAN)..
W a t e r C o n d i tit i o n s 7. Thin zone of radica radicall change in temperature betwe between en two distinct distinct layers layers of of water. 8. Locale, Locale, seasons, weather, water water movement, bot tom composition. 9. Disorie Disorientatio ntation n and dizziness. dizziness.
W a tet e r M o v e m e n t 10. Wind, tides, currents. currents. 11. Across the curr current. ent. 12. Into or against. 13. Gravitational pull, sun, moon.
M a r i n e Life 14. False. False. 15. Touch Touch something. something. 16. Sticker Sticker.. 17. Stinge Stinger. r.
Conservation 18. Touching, breaking. 19. Contain Contain no animals. animals. 20. Sea turtles. turtles.
NAU I Scuba S cuba D i ver
_H _9: 40 _
! D N E P P A
2 :1 3 _JL
10:19
_J
12:32 12:32
l :3 :3 0 _ _ G_ G_
1:13
21 (70)
MDT MD T = 45
15(50)' 15(50)' flM DT = 42
24(80)
MDT MD T = 35 35
2°( 67) 18(60 18(60)\ a m d T = 25
2:43
J L 3:26
12(40) \AM DT= 57 14(46) 15(50) \ AM DT = 24/
RNT = 0 ADT = 36
RN T = 38 AD T = 38
RN T = 73 73 ADT = 4 0
TNT = 36
TNT =
TNT = 113
76
12(40)
F IGI G U R E A 1 P L A N N I N G W O R K S H E E T P R O B L E M 1 _E
2:46
_____
C
_H
L e O o |
8:35
24(80)
MDT MDT = 35
27(90)
MDT = 25
_____
2 : 50
t \ i : 20 | _
\
24(80)
D
3 :1 0 \
3
I 4:10 1 - 3
15(50)' AMD T = 59
12(40)1 AM DT = 93 J
18(60)\ a m DT = 38
16(53) 15(50) \ AM DT = 51 / 10(33)
RNT = 0 ADT = 20
R N T = 17 ADT = 3 3
RN T = 37 ADT = 57
TNT = 20
TNT =
TNT = 94
50
F IGI G U R E A 2 P L A N N I N G W O R K S H E E T P R O B L E M 2 _E
:44_ :44_ _E _
9:56
J
10:40
1_:J50 1_:J50_ _ _F_
11:06
18(60;
MDT = 55
15(50)\ a m d t = 42
21(70)
MDT = 25
6.7(55) 18(60)\ a m DT = 25
12:56
12(40)\amDT- 69 15(50) 15(50) \ AM DT = 3 3 1 13.7(45)
RNT =0 ADT =23
RN T = 38 AD T = 23
RNT = 47 A D T = 30
TNT = 23
TNT =
T NT NT = 77
61
F IGI G U R E A 3 S A M P L E P R O B L EM EM 1 _G
1:31
8:34
10:32
10:05
\
18(60)
2:0 4
21(70 \AMDT= 19
E
12:36
6.8(55) 18(60) \AMDT= 25/
R NT NT = 30 A DT DT = 24
RNT = 38 ADT = 31
TNT = 31
TNT=
T NT NT = 69
54
1:10
15(50) lAMD T = 42 /
RNT =0 ADT = 31
F IGI G U R E A 4 S A M P L E P R O B L E M 2
208
J
18(60) i AMDT = 25 25
MDT = 55 MDT = 25
E_
1
Appendix A
_F
:30_ _ f _
8:33
9:03
_____
9:36
\
o
15(50) AMDT = 33
MDT = 55 MDT = 25
_J
18(60)
18(60 \a MDT =19
RNT = 0 ADT = 3 0
RN T = 47 ADT = 3 0
TNT = 30
TNT =
15(50)
RNT = ADT =
77
F IGI G U R E A - 5 S A M P L E P R O B L E M 3 1:00
F
18(60)
MDT = 55
18(6 18(60) 0)'' AMDT-
19
21(70)
MDT = 25
17(56) 21(70)\aMOT=
14
RNT = 0 ADT = 3 1
RN T = 36 ADT = 1 9
TNT = 31
TN T = 55
RNT = ADT =
F IGI G U R E A -6- 6 S A M P L E P R O B L E M 4 1:00
»
F
5
\
18(60)
MDT = 55
18(60)'AMDT = 19
21(70)
MDT = 25
17(56) 2HZ2)\ a MDT= 14
J
\
15(50) iAM DT = 33 / 16(52.5) 18(60 \AMDT = 19/ 19/
RNT =0 ADT = 31
R N T = 36 ADT = 1 9
R N T = 47 ADT = 25
TN T = 31
TN T =
TNT = 72
F IGI G U R E A - 7 S A M P L E PR PR O B L E M 5
55
NA UI Scuba Diver Div er
A P P E N D I X B
B E INI N G A R E S P O N S I B L E D I V ER ER As a responsible responsible diver, you must follow follow certain certain guidelines guidelines for etiquette (good (good manners), boat diving, and diving in general. general.
DIVER ETIQUETTE As a NAUI diver, diver, you should observe the followin following g guidelines for proper etiquette: etiquette: • Manage your equipment and vehicles vehicles as compact ly as possible so that you do not block block sidewalks, driveways, driveways, or public public accesse esses. s. Mainta Maintain in a tidy equipment equipment area to avoid clutte clutterr at the dive site. • Take care with spearguns. Loaded spearguns are forbidden on land and on boats, and any spear ing should should not be done in crowded beach areas. • Ask Ask before before using or crossing privat private e property, whether to gain access access to a dive site or for recreation recreation after a dive. dive. • Do not change clothes in public. public. Be discreet, discreet, and use vehicles, chang changing ing robes, or tents. tents. Think Think of others who are passing passing the site or using using the beaches. • Create a good impression impression of divers. Talk Talk pleas pleas antly antly to interested no non-dive n-divers rs who are curious curious about your sport. sport. Be careful careful of your language and behavior, behavior, partic particula ularly rly regarding the the use use of alcohol alcohol or other drugs drugs around dive activities. activities. • Do not violat violate e the rights rights of others to enjoy enjoy the environment, run businesses businesses,, or have a pleasant town town to live in. in. • Obey Obey all laws, whether they are fish and game regulations regulations or designated parking and access access areas. Coo Coopera perate te with loca locall police. • Do not litte litterr beaches or otherwise destroy proper ty. Beach environments are often fragile fragile ecologi ecologi cal cal systems that require your carefu carefull use if they are to survive. • Patronize Patronize local local merchants. Divers can have a positive economic impact on an area, from
restaurant restaurants s to dive stores to motels. Good eco nomic rapport with a community means means contin uing uing good good communicatio communication n and access access for divers. • Begin your dives early early in the day for optimum diving diving conditions conditions,, less crowded beaches, more parking, parking, and more more freedom freedom of choice regarding dive sites. sites. Do not exceed xceed your diving diving capabili capabilities ties in selecting selecting your site. site. Ask local residents or divers about possible possible sites, and rely on their their knowledge knowledge of water and bottom conditions. • Make Make sure sure that your fishin fishing g license is current current,, and obey obey local local fishing fishing regulations. Take only as much game as you can use. Collect Collect as littl little e as possible, clean fish only only in designated designated areas, areas, and dispose of any any waste properly. properly. • Be helpful helpful to other users users of our aquatic aquatic enviro environ n ment. It makes makes you, you, as a diver, better than the faceless crowd, crowd, and it gains respect for your your sport. sport. Also, it remove removes s many hassles of diving diving and makes makes you a happier, ca calmer, lmer, and safer diver. diver.
N A U I R E S P O N S I B L E B D A T D I V INI N G PRACTICES The NAUI NAUI Responsib Responsible le Boat Diving Diving Practices Practices include the following: • Select a licensed boat that is full fully y equipped equipped with all required safety gear, includin including g oxygen oxygen and other diver diver support and and safety equipme equipment. nt. • Ask to receive boat diving diving techniques trai trainin ning g as part part of your Advanced Advanced or Master Scuba Diver course. • Rely Rely on the captai captain’s n’s knowledge of the the most suit suit able dive site sites. s. Plan Plan your dive using th the e specific site informa information tion provided by the the crew or divemaster. • Sign up only for trip trip destinations consistent with your ability and dive plan. • Arrive Arrive at the boat at least least one-half hour before departure. Stow your well-marked gear in its its assigned assigned location, location, and respect the boat boat faciliti facilities, es, such as no wetsuits in the bunk cabin or not dropping weights weights or cylinder cylinders s on the deck. deck.
Appendix B
Between dives, keep your gear in in your your bag to avoid loss or breakage, and always assist your buddy with their their cylinder cylinder.. Do not sit on the the deck to don don your scuba unit, or you might get hit in in the head head by another diver’s cylinder. cylinder. Use Use your equipment properly to dive easily easily and safely. Do not overweight yourself. Only use use your buoyancy compensator to fine-tune your buoyan cy during during the dive or to compensate compensate for a heavy game bag at at the end. ' Do not take a loaded speargun on a boat or boarding ramp. ramp. Bring Bring a container for your game. Help keep the deck clean clean and clear. clear. Use the boat exit points that are identifie identified d by the 1 Use crew. Move away from the boat exit exit once you are in the water, and either snorkel snorkel clea clearly rly on the surface or begin your your descent down down the anchor anchor line. line. Do not use scuba to skim just beneath the surface. Doing so, you cannot be seen bypassing boats or other divers. 1Put your fins on last, while while you are waiting waiting near the exit. Donot walk walk around the deck wearing wearing fins. 1Use a compass and submersible submersible pressure gauge. Plan Plan your dive so that you end with a reserve reserve of air and are able to to return to the the boat while while still still under water, if need be. •Be aware of changes changes in curren currentt conditions during during the dive. Use natu natura rall clues such as seaw seaweed. Look for tra trailil lines extended behind the boat on the surface, surface, and do not hesitate hesitate to pull yourself hand-over-hand back to the boat using this this line line,, if need be. >Use common sense, train trainin ing, g, and experience. Ask questions if you are unsure. Allow a margin margin of reserve reserve, and do not push your endurance lim lim its. Watch for other divers who are waving waving their arms on the surface. This signals signals a diver who is in distre distress. ss. Divers who maint maintain ain personal control and are comfortable in the water have safe, enjoyable experience experiences s under water.
N A U I 'S R E S P O N S I B L E D I V E R P R A C T I C E S diver I understand that I should: As a responsible NAUI diver Be trained and certified for scuba diving. Maintai Maintain n good good physical and mental mental conditioning conditioning for diving and only dive when feeling well. Never Never usealcohol alcohol or other inappropriate inappropriate intoxicants intoxicants before diving. Always breathe continual continually ly and avoid “skip-b “skip-breath ing” or breath-holding while submerged on scuba. Use complete, well maintained maintained diving diving equipment and checkit itbeforeeachdive. Neverloan loanmy equipmentto non-certified non-certified divers. Always evaluate environmental environmental conditions before each dive and allow allow a margin margin of safety tobe preparedfor emergencies. Understand Understand my my personal personal limitati limitations ons as well well as the limitations of my training and strive strive to stay stay within them. Set moderate limits limits for for depth and time under water. water. Save sufficient sufficient breathing breathing gas to use as a contingency at the end of thedive and to complete a precautionary precautionary decompression stop. Use the buddy systemwhen divi diving ng and be prepared to assist my buddy and others if needed. Period Periodica ically lly review and practice rescue and assist assist skills skills previously learned in in my NAUI course. Usesurface support, such as a boat or dive floa floatt and diver down flag whenever required or feasible. Comply Comply with local rules and ordinances. ordinances. Be respectful respectful of others rights and strive strive to represent represent the diving community in a positive role. role. Accep Accept responsibility responsibility for my safety when when diving diving and preparing preparing to dive. Seekprofessional traini training ng and assistance to leam new divingtechniques, use unfami unfamilia liarr equipmentorwhen planning to dive in unfamilia unfamiliarr locations. Plan Plan each dive and utilize utilize dive tables or a dive com com puter to trac track k my decompression status. Delayflying or ascending to altitudeafter di diving vingcon sistentwith current recommendations. Respect game and collectin collecting g regulations regulations and the fragil fragility ity of the aquatic environment. Practice Practice good good buoyancy control and avoid unnecessarily making contact contact with corals or other aquatic plants and ani ani mals. Help others to understand the need to protect and preserve aquati aquatic c resources.
NA UI Scuba Sc uba D i ver
A P P E N D I X C CHECKLISTS Checklists are an excellent excellent way to make sure you do not forget anything when planning planning a dive or dive trip and packing for a dive. Use the checklists in thi this s appen dix as a base base for creating creating your own personal checklists checklists for dive planning, equipment, and first aid.
□ Seasickn Seasickness ess medication □ Fishing license license □ Light stick sticks s □ Defog efog □ Check the weather forecast, water conditions, tides, and long-range foreca forecast st □ Prepare a copy of your plans to leave with someone at home
P r e p a r ini n g t o D i v e
D IVI V E P L A N N 1 8 C H E C K L I S T Use the following dive planning checklists as guide lines for long-term long-term plannin planning, g, short-term planni planning, ng, and on-site planning.
L o n g - T e r m Planning □ □ □ □ □ □ □ □
Determine the objective of the dive Select your dive buddy buddy Select Select your location Select Select an alternate alternate location or activity Research the dive sites sites Obtain emergen emergency cy contact information Identify nearest nearest chamber chamber Determine the date and time of your trip
□ □ □ □ □
Make Make your travel arrangeme arrangements nts Determine your equipment needs Check Check your equipmen equipmentt Have your equipment equipment serviced, serviced, if necessary Determine Determine whether you need need to take a NAUI Refresher Experience □ Locate Locate your certification card
S h o r t T e r m Planning □ Inventory Inventory your gear gear □ Replace dried dried or or cracked cracked fin straps and mask mask straps and lost or frayed frayed O-rings □ Buy items items needed for your trip □ Air fills □ Film □ Sunscreen Sunscreen
□ Gather all your equipment equipment and personal personal articles in one place □ Pack Pack your dive gear gear in reverse reverse order order of its use □ Pack Pack your your personal personal gear gear in a separate separate bag bag □ Get a good night’s night’s rest □ Leave a copy of your dive plan plan with with someone one before you depart
On-Site Planning □ Site Survey Survey □ Evaluate Evaluate the conditions at the site □ Determine the leader of the dive □ Emergen Emergency cy □ Determine Determine your out-ofout-of-air air plan □ Determine Determine your lost buddy buddy plan □ Determine how to summon summon help in case of an accident accident □ Find the the neares nearestt working telephone □ Activity Activity □ Agree ree on your activity activity and objective objective □ Review your hand signals signals □ Decide Decide on your entry and exit points points and your dive pattern □ Set your limits limits for depth depth, time, and remaining air supply □ Buoyanc Buoyancy y □ Check your buddy’s weight system system for its quick release □ Checkyour buddy’s buddy’s BC to be sure you know how to power power inflate, orally orally inflate, inflate, and deflate deflate the BC BC □ Locate the releases on your buddy’s buddy’s BC
Appendix 6
□
□
Air □
Checkyour buddy’scylinder cylinder valve to besure it is ful fully ly open and back 1/4turn □ Check Check that the the cylinder is secure in the tank strap □ Checkthat your buddy’s buddy’scylinder is full full □ Check Checkyour buddy buddy’s ’sprimary and backup regulators for proper operation Gear and Go Check that your your buddy does not have any entangled entangled gear and that their their alter alter nate air air source and console are secured Check that your your buddy has mask, fins, and snorkel ready to don don Check that you have any any necessary necessary accessory equipment Proceed to your entry entry point Enjoy your dive
□
□ □
□ □
DIVING E Q U I P M E N T C H E C K L I S T Use Use the followin following g list list as a guideline guideline for the gear you need need to pack for a dive trip. trip.
P r imi m a r y D i v e D e a r □ □ □ □ □ □ □ □
Mask Mask Snorkel with keep keeper er Fins Fins Bootie Boo ties s Divingsui Divingsuitt Hood Glov Gloves es Weight belt belt
□ Buoyancy compen compensator sator □ Cylind Cylinder er □ Regulator set-up □ Primary regulato regulatorr □ Octo Octopu pus s regulator or alternate air source □ Depth Depth gauge, gauge, submersible pressure pressure gauge, compass □ Timing devic device e □ Dive computer computer □ Dive Dive knife knife □ Gear Gear bag bag □ Dive Dive tables tables
□ □ □ □ □ □
Float, flag, and and float anchor Dive Dive light Slate and pencil Thermometer ometer Marker buoy buoy Game bag
□ □ □ □
Cylinde Cylinders rs Weigh Weights ts Mask strap strap Fin stra straps ps
NAU I Scuba S cuba D i ver
□ O-rings □ Snorkel keep keeper er □ Tool Tools s
F IRI R S T A I D K I T C H E C K L I S T You should have have a first first aid kit kit with you whenever whenever you dive. dive. The followi following ng items are basic. You can sup sup plement them according according to your personal need needs, s, level of
E m e r g e n c y I tet e m s
first first aid traini training, ng, and distance distance from from medical assistan assistance.
□ First-aid First-aid kit □ Telephone Telephone numbers numbers for local local emergency emergency services, nearest chamber, chamber, and DAN
General □ Sterile Sterile compress pads pads
□ Coins for telephone telephone
□ Assorted orted sterile sterile gauze gauze pads
□ Oxygen kit
□ Assorted adhesive bandages □ Triangular Triangular bandage dage
P e r s o n a l ItI t e m s □ Certification card □ NAUI logbook □ Fishing license license □ Swimsu Swimsuit it □ Towe Towell □ Hat or visor
□ Roll Roll of 5 centimeter centimeter (2 inch) inch) gauz gauze e bandag bandage e □ Adhesive Adhesive tape, 2.5 2.5 centimeter (1 inch inch)) □ Cotton swabs abs □ Aspirin or other other analgesic analgesic □ Assorted safety pins/needles □ Sciss Scissors ors □ Tweezers or splinter splinter remover remover □ Antiseptic Antiseptic soap soap
□ Sunscreen Sunscreen lotion
□ Antiseptic Antiseptic cream or spray
□ Sunglass Sunglasses es
□ Medicate Medicated d stick
□ Lunch or snac snacks ks
□ Isopropyl Isopropyl alcohol (70% solution)
□ Drink Drinks s
□ White White vinegar vinegar
□ Jacke Jackett
□ Sunscreen Sunscreen lotion
□ Extra clothing clothing
□ Change Change for telelphone telelphone
□ Ticke Tickets ts
□ Emergency telephone numbers numbers
□ Money Money and credit cards cards □ Seasickn Seasickness medication □ Toilet Toiletries ries
□ Hydrogen Hydrogen peroxide peroxide □ Gauze scrub pads □ Baking soda □ First-aid First-aid book book □ Sports Sports drinks □ Waterproof matches matches □ Drinking Drinking water and paper paper cups cups □ Blanke Blankett □ Seasic Seasick k pills
Appendix B
NA UI Scuba Sc uba D i ver
Glossary
Backup Scuba: A redundant secon second d stage or total
ft
BC: Buoyancy Compensator.
scuba unit unit for use use in out of air situations.
Absolute Pressure: The total surrounding surrounding pres sure and the result when atmospheric pressure pressure is added to gauge or or water water pressure.
Bends: Another name for for one type of decompression sickness.
Actual Dive Time: The total time spent under water from the beginning of descen descent until until breaking the surface at the end of the dive. The precautionary precautionary decompression stop need not be includ included. ed.
ring on a compass compass or watch Bezel: A movable ring inscribed with index marks. marks. On a watch, the ring can be rotated rotated only counter counterclockwise clockwise and is used
Adjusted Maximum Dive Time: The Maximum Dive Time for a specific depth depth minus the Residual Nitrogen Time for for a specific specific letter letter group and depth.
Buoyancy: An upward upward force on an object placed in in
to measure elapsed time.
water that that is equal to the weight of the water dis placed. Loosely, buoyancy is applied to to the the net state of an object, object, such as as “positive “positive buoyancy” for
Alternate Air Source: An addition additional al second second stage regulator that that provides provides air air to a diver’s diver’s buddy buddy in an emergenc emergency. y. A true alternate alternate air air source is a com pletely independ independent ent unit consisting of a cyli cylinder nder and regulator. regulator. See also Octopus ctopus Regulator. Regulator.
an object that floats. Buoyancy Compensator: A piece of equipment equipment that can provide increased volume by adding air air to a bladder, thus providing providing lift. lift. Buoyancy Jacket: A buoyancy control device
ADT: Actual Dive Time.
shaped shaped and worn like like a vest.
blood flow in in the Air Embolism: The blockage of blood body by bubbles in the blood.
Boyle’s Law: Statement of a physical principle - The inverse relati relationsh onship ip between between pressure and volume
Ambient Pressure: The total total surrounding surrounding pressure. See absolute pressure.
of a gas. Buddy System: The practice of never diving alone. alone.
AMDT: Adjusted Maximum Maximum Dive Time.
You always always have someone to assist you, if neces sary, and with whom to share experience experiences.
Alveoli: The air air sacs in the lungs where gas exchange occurs. 0
Atmospheric Pressure: The pressure exerted by the atmosphere.
C-Card: Certification card. Carbon Carbon Monoxide M onoxide Toxicity: Toxicity: A risk or condition that results from breathing air air contaminated with
B control device Back Flotation System: A buoyancy control whose entire bladder bladder is behind behind the diver and does not wrap wrap around around the diver in any way. Backpack: A piece of equipmen equipmentt designed to hold a scuba scuba cylinder on a diver’s back, back, usually usually integral integral with the buoyancy compensator. compensator.
carbon monoxide. Cardio-pulmonary Resuscitation: The first-aid procedure that sustains vent ventila ilatio tion n and pulse unti untill a person’s person’s heart and breathing resume on their ow own n or until until other medical procedures dures can be initiated.
GLOSSARY
the body, such as the nerves, they have a negative negative impact and cause a variety variety of signs and symptoms ptoms that signal signal the diver is sufferi suffering ng from decom decompres pres sion sickness sickness.
Ceiling: The minimum dept depth h (usu (usuall ally y displayed by a computer) to which a diver can ascend without enhanced risk risk of decompression sickness. Certification Card: A card card awarded by NAUI as evi dence of completing specific diver train training. ing.
Defog Solution: A substance rubbed or sprayed on the lens of the mask to keep it free of condensa condensa tion. Sali Saliva va is often used as a defog defog solution. solution.
Clearing: The movement of air air from the lungs lungs to other air air spaces, such as the ear and the sinuses to equalize pressure.
Dehydration: A lack lack of adequate body body fluids.
Compass: A piece of equipment equipment that aids in under water navigation by indicating the direction of magnetic north from your position.
Density: The mass mass per unit unit of volume. Depth Gauge: An instrument or device device that indicates indicates depth.
Condensation: The water that forms on a surface because of the cooling cooling of air air contai containing ning water vapor.
Dive Computer: An electr electroni onic c device that that senses
pressure, pressure, measure measures time, continuously continuously calculat calculates es the amount of nitrogen in in several theoretic theoretical al body compartments, compartments, and displays the information information to help divers avoid avoid decompression sickness.
Console: A device device designed to hold assorted assorted gauges and instruments instruments around or in line line with the sub mersible pressure gauge. Coral: A marine marine anima animall without a backbone that usually usually lives together with other animals animals of the same species and forms a colony. Many Many corals corals produce produce a hard hard external external skeleton. skeleton.
Dive Schedule: An abbreviated sta statement tement of the depth and duratio duration n of a dive dive expressed as depth/time. For example, 21 meters (70 feet) for 40 minute minutes s or 21/40 (70/40).
CPR: Cardiopulmonary resuscitation.
Dive Time Calculator: A rotary calculator contain ing the NAUI NAUI Dive Tables Tables in a format that elim elimi i nates nates the mathematical calculation calculations s associa associated ted with the dive tables. tables.
Current: The flow or movement of water in in a specific direction. direction. Wind, gravity, temperature, the Earth Earth’s ’s rotation, and other factors ca cause use currents.
Drag: The resistance encountered when moving through the water because because of the water’s water’s density.
Cylinder Valve: A mechanism mechanism used to control control the flow of air air in and out out of a scuba scuba cylinder. The cylinder valve includes the attachment attachment point for a scuba regulator.
Drift Diving: A dive made using a curre current nt as the pri pri mary means of propulsion.
D
Dry Suit: Aprotective suit suit that excludes water and Decompression Stop: The specified specified depth and time a diver stops and waits during during ascent to allow allow for nitrogen elimination before surfacing. Decompression Sickness: The adverse adverse physiologi physiologi cal cal symptoms or condition condition caused caused by the forma tion of of bubb bubbles of nitrogen wit within hin the body body of a diver. When these bubbles act on variou various s parts of
prevents it it from coming into into contact with with covered portions of the body.
E Ear Drum: The membrane tha thatt separates the middle and outer ears. ears.
NAUI Scuba Diver
Entry Scuba Experience Program: A NAUI NAUI pro gram to introduce introduce non-divers to scuba diving. diving. This program doe does not award certifica certification. tion.
check the expansion and recovery of the scuba cylinder walls. Hyperventilation: Breathin Breathing g much more deeply deeply and rapidly rapidly than required. This lowers the carbon dioxide level level in the blood, blood, which which decrea decreases the stimulus to breathe.
Equalization: The method of preventing and cor cor recting recting squeezes. Also see Clearing Clearing.. ESE Program: Entry Scuba Experience program. Eustachian Tube: The tube that connects the mid dle ear with the throat, through which divers can equalize their their ears. ears.
I
Index Marks: The points points on a compass bezel that provide a place place to lay lay the needle to stay on a desired course.
F
Integrated Weight System: System: A system in which which weight is combined with the backpack and buoyan cy compensator.
Fins: A piece of equipment that that attaches a blade to the foot to increase the surface surface area area of the foot to to increase propulsion thrust. Foam Neoprene: A rubber-based mater materia iall saturated with tiny tiny gas bubbles to provide insulation insulation.. This material material is used used to manufacture div diving ing suits.
L Letter Group Designation: A letter used used to identify identify set set amounts amounts of residual nitrogen in a diver’s diver’s body ody after a dive.
fi
Longshore Current: A current that runs parallel to Gauge Pressure: The pressure indica indicated ted by a gauge calibrated calibrated to ignore atmospheric atmospheric pressure pressure..
a coastline. Low-Pressure Inflator: A device that allows allows air air from from the scuba cyli cylinder nder to be added added to the the buoyancy compensator.
Goggles: A piece of equipment equipment that only only covers the eyes to prevent water from irri irrita tatin ting g them. Goggles are not an acceptable acceptable substitute for a mask.
Lubber Line: Line: The reference line line on a compass. The stationary stationary line that show shows the the direction direction of travel.
H Heat Exhaustion: A condition condition resulting resulting from over heating that is characterized by a pale, clammy appearance and a feeling feeling of weakness. Heat Stroke: A condition condition resulting resulting from overheating that is characterized characterized by hot, hot, dry, and flushed skin. This is a life-threateni life-threatening ng emergency. Hose Protector: A piece of heavy plastic plastic or rubber that fits fits over the end of a hose to to relieve relieve the stress caused by the weight of the equipment. equipment. Hydrostatic Test: A test required required to ensure the safety of scuba cylinders. This test is done done using water as the medium to provide provide pressure to
Lungs: The organs of the body that allo allow w oxygen to transfer from inha inhaled led air air to the blood. blood. One of the body’s air air spaces.
M Mask: Apiece of equipment that holds a pocket pocket of air around the eyes to improve underwater vision. vision. The nose is always included in any mask to allow pressure inside it it to be equalized. Maximum Dive Time: The length of time that can be spen spent at at a given depth without without being required to stop stop during during ascent to reduc reduce e the likeli likelihood hood of decompression sickness.
GLOSSARY
Oxygen: The gas that is necessary to sustain life.
MDT: Maximum Dive Time. Mediastinal Emphysema: Emphysema: The condition that exists when when air air from a lung overexpansion injur injury y escapes into the chest area near the heart.
Oxygen makes up approximate approximately ly 20.9% of the air air.. P
Pneumothorax: The condition that exists exists when when air air
from an overexpansion injur injury y escap escapes es into a
Middle Ear: The spac space e in the ear contai containin ning g the auditory bone bones. It open opens s into the throat through the Eustachian tube.
pleural cavity. Positive Buoyancy: The state that exists when an
object floats or rises rises in water. Actually Actually a redundan cy, as buoyancy is always a positive positive (upward) (upward) force. force.
Multilevel Dive: A dive involvin involving g periods periods of time at different depths.
Precautionary Precautionary Decom pression Stop Stop:: Aperiod of
N
three to five five minutes minutes spent at a depth of 5 meters
NAUI: National National Association of Underwater Instructors. Also Also called called NAUI Worldwide.
(15 feet) as a safety precauti precaution on even though the Maximum Maximum Dive Dive Time Time has not not been exceeded.
Negative Buoyancy: The state that exists when an object sinks. Actuall Actually y a contradi contradiction ction in terms. terms. Buoyancy is positive by definition.
Pressure: The application of force. force. In diving used
for the force force of the weight weight of the air air and water water above above a diver diver measured in bar or pounds per per
Neutral Buoyancy: The state that exists when an object neither floats nor sinks.
square inch. Pressure Gauge: A piece of equipment that allows
Nitrogen: The gas that forms forms 78% of the atmosphere. It is metabolically inert but is the gas that causes decompression sickness sickness and nitrogen nitrogen narcosis. narcosis.
one to measure the pressu pressure re of air air in a scuba cylinder. Pressure Relief Disk: A thin piece of metal placed in cylinder cylinder valves, that ruptures to prevent pressure
Nitrogen Narcosis: The name given tto o the disori disori enting effect nitrogen has on the brain at increased pressure.
from reaching reaching dangerous levels. Also called called a burst disk. It It is a one-time use device that that must be replaced if it bursts.
0
Octopus Regulator: An extra extra second stage stage attached to the the regulator regulator for use in out of air situations.
PSI: Pounds per square square inch. inch.
0 Quick Release Buckle: A buckle designed to be
One Atmosphere: The force of the at atmosphe mosphere at sea level on the earth earth taken as a constant, constant, equal equal to 14.7 pounds per square inch, inch, or approximately approximately 1bar. Overexpansion Overexpans ion Injury Injury:: An injur injury y caused by the expansion of air air rupturing rupturing enclosed body spaces paces. Overpressure Valve: An device built into buoyancy compensators, which which allows the escape of excess air air without without damage to the buoyancy compensator.
operated with with one hand hand so it can can be opened opened quickly quickly in an emergency. ergency. R
Rapture of the Deep: An older, quain quaintt term for nitrogen narcosis. Reference Line: The lubber line line on a compass. The stationary stationary line line that that shows the direction of travel.
NAU I Scuba Sc uba D i ver
Regulator: The piece of equipment that that reduces
high-pres high-pressure sure air in the scuba scuba cylinder cylinder to ambient pressure on demand. Relative Humidity: The amount of water held in the air air compared to what the air air can hold hold at that temperature. Repetitive Dive: Any dive made before complete outgassing from a previous dive. On the NAUI
Dive Tables, this this is 24 hours. Required Decompression Stop: An amount of
time specified by dive tables, a calcul calculato ator, r, or a computer that that must be spent at a specific specific depth whenever the Maxi Maximum mum Dive Time Time is is exceeded. Residual Nitrogen: The dissolved dissolved nitrogen nitrogen remain remain ing in the body because of a previous dive or dives. Reverse Block: The opposite of a squeeze. The sit sit uation uation that exists when the internal internal pressure of of an air air space is greater than the external pressure pressure and blocks its own escape route by deforming deforming
body tissues. Rip Current: A current current that that results when water pushed up on the beach beach by waves rushes back to the sea sea through a narrow channel. channel. RNT: Residual Nitrogen Time. Time.
S SAC Rate: Surface Surface Air Consumption Rate. Safety Stop: See See Preca Precautio utionary nary Decompression mpression Stop. Stop. Scrolling: A sequential display on a dive computer between dives to provide the Maximum Maximum Dive Dive Times for various various depths, on the next dive, or other lists lists of data. Scuba: Self-contained Self-contained underwater breathi breathing ng apparatus. Scuba Diver Course: The first course course in in NAUI’s complete complete diver education education program. This course leads to certification.
Scuba Cylinder: Thepieceofequipment containing containing
the high high pressure air air to be breathedwhile while underwater. Service Pressure: The working working pressure pressure of the
scuba cylinder. It is stam stamped ped on the the shoulder of the cylinder. Sinus: An air cavity in in the skull lined with mucus mucus
membranes. Sinuses can cause problems problems with equalizi equalizing ng if if they are blocked because because of swelling, swelling, as with colds or allergies. SIT: Surface Interval Time. Skip Breathing: The hazardous hazardous practice of taking a breath and holding holding it as long as possible possible before
exhaling while while scuba diving. This practice is done to supposedly extend bottom time. Snorkel: A tubula tubularr piece of equipment that allows a person person to breathe while keeping their face in the water. SPG: Submersible Pressure Gauge. Squeeze: The condition condition that that results when the pres pres sure outside outside an enclosed air air space space is greater than
the interna internall pressure pressure. Standing Current: Awater flow that that is constant
and steady. Submersible Pressure Gauge: A piece of equip
ment that provides a display display of tank pressure pressure during a dive. Surface Air Consumption Rate: The amount of air air consumed consumed at the surface in a set set period. period. Surface Interval Time: The time spent on the sur
face face between dives. Skin Diving: A type type of diving diving that that is done by hold ing your breath. Also known as free free diving diving or
breath-hold diving.
GLOSSARY
T
w
Test Date: A date stam stamped ped on on a scuba cylinder cylinder indi indi cating cating the date of the last hydrostatic hydrostatic test. Thermocline: The dividing dividing line line between water of different temperatu temperatures. res. Tide: The change in water level level of the ocean caused caused by the gravita gravitation tional al attrac attraction tion between the Earth, Earth, Moon, and Sun. Tidal Current: Awater flow flow that accompanies change changes in the tide, tide, usual usually ly a result result of water flowing into or away from an area area such as an inlet inlet or bay. Timing Device: A device used to record the length length of a dive. For example, a watch or bottom bottom timer. Total Nitrogen Time: The sum of Residual Residual Nitrogen Time and Actual Dive Time fol followi lowing ng a repetitive dive. Trail Line: A floatin floating g rope used while while boat diving. diving. It is extended from the stern of the boat with an attached float to aid divers returning returning to the boat. boat. Transitory Current: Current: A current that lasts only for a short time and, unlike unlike a tidal tidal current, current, does not not occur with any predictability.
V Valsalva Maneuver: Maneuver: The term popularl popularly y used to describethe attempted exhalat exhalation ion against against a closed nose and mouth to open the Eusta Eustachi chian an tubes and equalizes the ears. Vertigo: A loss of the sense of balance. Severe dizziness. Visual Inspection: A periodic periodic inspection inspection of a scuba cylinder cylinder that that checks for corrosion corrosion and to ensure ensure the integrity integrity of the cylinder. cylinder. It is also known as a Visual Cylinder Inspection (VCI) (VCI) or Visual Inspection Program (VIP).
Wetsuit: A diving suit suit that allows a sm small all amount of water to enter the covered covered area. This water is trapped inside inside the suit suit and warmed by the body, thus providing a certain certain amount of protection protection from the cold, in addition to the insulation afforded afforded by the suit itself. itself.
NA UI Scuba Diver
Archimedes principle
Index
97
.......................................
Artificial respiration, in-water
............................
168
Ascents Assisted Buddy breathing
77 78
....................................................
........................................
fl
Dependent emergenc emergency y
77
Emergency buoyant Emergency swimming General procedure
79 79 75
..................................
Absolute pressure Activities
102
......................................
....................................
.................................
Clubs Continuing education
189 189
................................................
............................
.......................................
Independent emergency
79
Normal
75
Octopus
77
Rate of
75
...............................
Special interests
....................................
192
...................................................
Activity, dive 153 Actual Actual dive dive time time (AD (A D T) 128,131,138 Adjusted maximum dive time (AMD (AMDT) T) 128,132 ADT See Actual dive dive time (ADT) (ADT) ............................................
...................................................
......................
.............................
.................................................... ....................................................
Assisted ascents Atmosphe Atmospheric ric pressure pressure
.....................................
Advance Advanced d scuba diver diver course 198 Air 94 Characteristics Composition 94 Consumption, depth and.........................105 ........................
...........................................
.............................................
Embolism Enriched Expansion, diving diving problems problems caused by Monitoring supply
113 95,118 112 72,106
77 101 82
..............................................
Audible signals
..............................................
B Back flotation systems
33
Back roll entry
63
......................................
..........................................
.........................................
.............
..............................
Pressure Sharing with anoth another er diver diver Sources, alternate Starvation Air-integrated dive computer computer Alcohol, avoidance of
99 77 26 115,165 28 142
..................................................
...............................................
Backpacks Backup gear Backup scuba BAR, pressure measurement measurement and and
24 155 27 101
....................................................
................................................
................................................
........................
............................
.......................................
.......................................
Barotrauma BC
107 See See Buoyancy control devic devices
.................................................
Beach entries
..............................
................................. .................................
Alpha dive flag 44 Alternate air sources 26 Altitude diving 139 Aluminum cylinders 20 Alveoli, Alveoli, effects of pressu pressure re on on 112 Ambient pressure 25,104 AMDT AM DT See Adjusted maximum dive time (ADT)
Calm water Rock
64 64
Surf Beach exits Calm water Rock Surf
64
...............................................
.......................................................
...............................................
........................................
.........................................
........................................
........................
...................................
Anatomy Lungs Middle ear Sinuses Apprehension, diving Aquatic life injuries
...............................................
.........................................
..............................................
........................................................ ........................................................
...............................................
.......................................................
........................................................ ........................................................
Belt, weight Bends
.........................................
...................................
171
36, 58,60,86 See Decompression sickness
.....................................
..........................
112 107 110
66 66 66
Biting marine life Blast method of clearing snorkel Blocks Definition
..........................................
185 54
.........................
8
...............................................
Middle ear
........................................
107
107,109
INDEX
Ill
Neutral
183 207 l6l
Positive Salt water and
Stomach and intestines
....................................................
...............................
Boat diving Boat diving practices Body-core y-core temperatur temperature e
..........................................
......................................
Booties Fit Fit Purpose
98 101
...................................................
.................................................
....................................
98
Buoyancy control Ascending Checking buoyancy buoyancy at surface surface
75 73
................................................
18 17
..........................................................
...................................................
Types Bottles
.........................
Checks
17 See Cylinders
Boyle's law
103
39 74
Effect on environment
................................
.......................................
188
Factors affecting Skills
.........................................
..................................................
...........................................
Dry suits During the dive
..........................................
.......................................
Breath-hold diving
73
...................................................
............................................
179 28
Descending
...............................................
......................................................
Bottom composition Bourdon tube tube gauges gauges
100
...................................................
5
......................................................
99 72
Buoyancy control devices
Breathing Air starvation
...........................................
115
Carbon monoxide and and
118
Circulation and Howcarbon dioxide controls controls
114 114
................................
.........................................
Rate of Shallow
............................................ ............................................
Horse collars Integrated weight systems
.............................................
..............................
Ja Jacket kets
116
Without a mask
Orally inflating Purpose Removing and replacing in water
..........................................
...................................................
....................
69
Buddy Ascend Ascending ing with with Descending with
32 85
Selection
34
..................................................
......................................
..........................................
34 71
.............................................
.............................................
69
34
Maintenance
115 114
With flooded mask
34 34
.....................................................
105,114 115
......................................................
32
...................................................
..................................................
Skip Underwater
Features
.....................................
Hyperventilation........................................115 Inhaling water
33 60
............................................
........................................
........................
Back flotation Donning scuba unit
Types Burst disk
......................................................
33 23
.....................................................
..........................................
75 74
.........................................
Helping
166
C
..................................................
Procedure for lost
81
California, diving Capilla Capillary ry depth depth gauge
System
80
Carbon dioxide dioxide and breathin breathing g
36
Carbon monoxide toxicity Ceiling, dive computers and Certification, scuba Chamber, recompression
Limited Limited visibility and and
180
..................................
.......................................
....................................................
Bullet weights Buoyancy Archimedes principle Checks
97 100
Displacement and
98
Factors affecting Fresh water and and Lead weights and and Negative
99 101 100 99
...............................................
...................................................
.......................................
.........................................
......................................
192 28
......................................
...........................
114
118 142 5 114,117
................................
.............................
...................................
........................................
..........................................
..................................................
...........................................
...........................
Characterist Characteristics ics of a site site
...................................
Checklist Dive planning
176 212
..........................................
Diving equipment First aid kit
.....................................
213 214
..............................................
223
■
NAU I Scuba D i ver
Chilling, Chilling, heat loss loss and Choking
9 6 ,160 116,164 114 42 211 109, 111 139 109, 111 See Pneumothorax 190 95
............................
............................................
Circulation
..................................................
Clips
..........................................................
Code, responsible dive diverr
....................................
Cold medication
.....................................
Cold or strenuous strenuous dives dives
...................................
Cold, Cold, head, head, diving with w ith Collapsed lung Collecting shells
.............................
..........................
...........................................
Colors Colors under water water
..........................................
Communication
Specialty
................................................
Training assistant assistant
.....................................
Cozumel, diving Cramps, muscle
...........................................
...........................................
Current line
................................................
Currents
....................................................
Cylinders Accessories
...............................................
Affect of temperature change on Aluminum
...............................................
Backpacks
................................................
Burst disks
...............................................
Surface
....................................................
Underwater Compass Compass navigation Computers
...............................................
......................................................
84
Characteristics
82 30
Hydrostatic testing Maintenance
88 See Dive computers
........................................
Conservation
...........................................
......................................
............................................
Markings Purpose
.................................................
....................................................
Regulating standards Service pressure
...................................
Cleaning up the environment environment Collecting
190 190
Hunting
189
.......................
...............................................
.................................................
Positive diver impacts
.........................
188,189
Wrecks
190
Console Contact lenses
27 68
...................................................
.......................................................
...............................................
Contin Contingen gency cy plan plannin ning g
....................................
.........................................
Sizes
.......................................................
Steel Storage Valves
.......................................................
....................................................
.....................................................
Visual Inspection
......................................
154
Contingency Contingency scuba scuba
..........................................
27 Decompression
Continuing education education Advance Advanced d scuba diver diver
198
Leadership courses
199
Master scuba diver Specialty courses
199 198
..................................
.....................................
.....................................
.......................................
Training assistant specialty Coral reefs Growth of Touching Core temperature Coughing Courses Advanced Leadership Master
..........................
....................................... .......................................
199
Dive time planning and
..........
Omitted stop Precautionary stop Required stop Decompression chamber Decompression sickness
.......................
................
......................
.............
..............
187,188 19 l6l 164
.................................................
...........................................
...................................................
...................................................
..................
............................
.............
198 199 199
................................................
..............................................
Decompression stop, precautio precautionary nary Defogging solutions Dehydration Density Direct effects effects in water Pressure effects
....................
Dependent emergency ascents Depth
*
INDEX
Dive ive tim time pla plann nnin ing g and... and. .... .... .... .... .... .... .... .... .... .... ...13 .133 3,135 Exceeding dive computer's maximum 145
Cold, dive table rules rules Contingencies
139 153
Monitoring air consumption
Emergency plans Equipment
153 150
.............
..........................
Depth gauge Bourdon tube Capillary Electronic
72
...................................
...........................................
.......................................
..............................................
............................................
..................................................
................................................
Depth limits for divers
.....................................
28 28 28
124
Descents 74 Controlled Free........................................................74 Rate of 74 ................................................
.................................................... ....................................................
DIN valve
...........................................
23,56,89
Disorientation
..............................................
Displacement, buoyancy and Distan Distances ces,, estimatin estimating, g, clear visi visib bility ility
163 98 181
..............................
...................
Dive computers
Flying after after diving, rules for
139
Ingassing nitrogen Limiting depth
124 137
Limiting dive time Location
137 150
Longterm Objective
Outgassing nitrogen
150 150 124
Packing Pre-dive plan
155 150
..........................
.....................................
.........................................
.....................................
.................................................
...............................................
.................................................
...................................
.................................................
...........................................
Repetitiv Repetitive, e, time limits fo for
135
Short range Single, time limits for
152 137
Site survey Strenuous, dive table rules
153 139
Surface intervals
136
Timing
151
.............................
.............................................
.................................
Air-integrated Ceiling
28 142
............................................
...................................................
Displays
...............................................
...........................
.......................................
Decompression Dive mode
.......................................
............................................
145 144
...................................................
Weather conditions, checking checking Dive planning worksheet Entering information in logbook
.......................
Initialization Scrolling Exceeding maximum depth of
143 144 145
Flying after diving
146
Finding a letter group Planning a dive
Logging dives
146
Planning repetitive dives
Overview
143
Recording repetitive dives Surface intervals Dive recording
.........................................
..............................................
....................... .......................
.....................................
..........................................
................................................
Planning repetitive dives
146
Rules Safe to fly indicators Terms
147 146 142
.............................
.....................................................
..................................
....................................................
152
....................
155
128,133 133
...........................
.........................................
.............................
.............................
.......................................
..............................................
135 135 137 155
Dive tables Overview
.................................................
127
Turning on 143 Violation of ascent rate................................145 Dive console 27 Dive flags 43
Recording in logbook
155
Rules Special rules Table One
128 137 130
Dive floats Dive knives Dive planning
Table Three Table Two Terms
131 130 127
.............................................
..................................................
.....................................................
....................................................
...................................................
43 42
.................................
.....................................................
............................................
...............................................
.............................................
...............................................
....................................................
Activity Altitude, rules for Checklist
151 139 212
...................................................
.......................................
................................................
Dive Dive time time calculator, NAU NAUII Dive time limits
...............................
............................................
Dive timers
139 125
...................................................
31
NAU I Scuba S cuba D i ver
Divers Alert Network Divers down flag
139,170 44
................................
.............................................
Diving equipment checklist Diving skins Diving suits suits
..............................
213 38
..................................................
Independent Swimming
................................................
Emergency plans Emphysema, mediastinal
153 113
...........................................
................................
End-Of-D End-Of-Dive Letter Group ta tabl ble e Enriched air Entanglements Entries Entries and exits exits
130 95,118 162
.........................
Choosing Choosing based on conditi conditions ons
41
........................
Donning 59 Dry suits........... ...... ........... ............ ............ ............ ........... ........... ...........3 .....39 9 Hoods 42 Maintenance 40 ..................................................
.....................................................
.............................................
............................................
.............................................
Back roll entry Beach
...........................................
63
Purpose
37
Calm water entries
64
Skins
38
Calm water exits
66
Rock entries Rock exits Surf entries
64 66 64
Surf exits
66
...................................................
......................................................
Wetsuits Diving your plan
38 154
Dizziness Dolphin kick
163 52
..................................................
...........................................
....................................................
.................................................
Drag Drift diving Drugs and alcohol, alcohol, use of and
97 183,192
..........................................................
...........................................
....................................
......................................
...........................................
..............................................
.............................................
...............................................
Boat and platform entries Boat and platform exits Giant stride entry
..............................
................................
.......................................
scuba scuba diving diving
Dry suits Buoyancy control Choosing based on conditio conditions ns Features
62 65 62
10
How the site affects affects
178
40 41 40
Ladder exits Seated side entry Shoreline conditions Swim platform exits
65 63 178 65
..............................................
.....................................
..............................................
.......................................
.........................
..................................................
Maintenance Operation
............................................
.................................................
Specialty training
.......................................
Squeezes Types
................................................
40 40 39
107 40
......................................................
Dump Dump valve, buoyancy compensator compensator Dust cap
33, 75 30,55,56,89
................
........................................
.........................................
..................................
....................................
Environment Boat diving
183
..............................................
Bottom conditions Cleaning up
178 190
Collecting
190
.....................................
.............................................
...............................................
Conservation of
........................................ ........................................
Currents Diving techniques Hunting
E
187
183 176,179 189
.................................................
...............................
.................................................
Marine life Moving water
..............................................
Ear Electronic depth gauges Embolism, air Emergen Emergencies cies and first aid aid Emergency Emergency ascents Buoyant Dependent General guidelines
..............................................
See Middle ear 28 113 169
....................................
..............................................
................................
..................................................
...............................................
......................................
226
79 79
.............................................
...........................................
Negative Negative diver impacts impacts Physical characteristics Positive diver impacts Shore Shore conditions conditions Surf
188 176 188 178 182
Thermocline
181
................................
...............................
.................................
.......................................
79 77 80
185 182
....................................................... .......................................................
............................................
......................................... ........................... ......................... ................... ....... 183 Tides...........................
INDEX
Visibility
.................................................
Water Water conditions conditions
.......................................
180
Surface flotation
180
Testing scuba unit Thermal protection
Water temperature Waves and surf surf
181 182
Wrecks Equalization methods
190 107,109
.....................................
......................................... .........................................
...................................................
..............................
Equipment Accessories Additional instruments Alternate Alternate air air sources sources
42 31 26
Assembling scuba unit Attachment devices
55 42
Backpacks
24
........................................
......................................
.....................................
Weights and weight belts belts
..........................
.................................
....................................
..................................
.....................................
................................................
Basic personal
15
Booties Buoyancy compensators Buying
17 32 14
Checking
6l
...........................................
....................................................
...............................
....................................................
.................................................
57 37
34,36
Etiquette, diver Eustach Eustachian ian tube, pressure pressure on ears and and Evaporation, overheating and
210 107 l6l
Exertion, air air consumpt consumption ion and and Exhalin Exhaling g when when regulator is out
105
.............................................
.................
...........................
...............................................
44
..........................
of mouth underwater Exit Ex its s
69 See See Entries and exits exits
...................................
F Feet first dive Fins Figure four position Full-foot
.................................................
.....................................
...................................................
53 52 18
Contingency scuba
27
Heel-strap
Cylinders
20
Kicking Kicking with with
52
163
Purpose
18
Dive flags Dive floats Diving instruments Diving suits
43 43 31 37
Selection
18
Types
18
Donning Fins
49 18
......................................
..................................................
Difficulties
..............................................
.................................................
................................................
.....................................
..............................................
..................................................
........................................................
.................................................
..............................................
....................................................
..................................................
.......................................................
Using
......................................................
First aid First aid kits
............................................
Fitness
27 43
Alpha Divers down
Gloves Hoods
19 40
Recall
Knives Logbooks Maintenance of basic
42 44 19
Masks Preparing for use Regulators Removing and replacing replacing scuba unit in water
15 48 25
Snorkels
16
.................................................
.....................................................
.....................................................
.....................................................
.................................................
...................................
......................................................
.......................................
...............................................
..........................................
..........................................................
...................................................
9
Flags 43 43,202
......................................................
........................................
84
......................................................
Sport diver
................................................
U.S. dive flag Flags and floats
.............................................
.............................................
Float Float plan pla n Flooded Flooded mask, mask, breathing wit with h Flotation device device
43 43 43
191 69 See Snork Snorkelin eling g vest vest
...................................................
............................
.........................
Flying after diving Free diving Free-flowing regulator Fresh water pressure
139 5,54 70 101
.........................................
.................................................
85
19
...............................................
Gauges Gear bags
....................................................
169 44, 214
Fish, touching
44 19
..........................................
50
......................................................
First aid kits Flotation device
..............................................
18
.....................................
.......................................
NAU I Scuba Sc uba D i ver
Pressure on ears
G
107
........................................
Reverse block Sinuses Humidity
107,109 110 120
Hunting Hydrostatic testing Hyperbaric chamber Hyperthermia Hyperventilation
189 24 114,117 l6l 115
.....................................
Galapagos Islands, diving
194
Gauge pressure Gauges
102
Compass Depth gauge
30 28
................................
.............................................
...................................................
....................................................
......................................................
..................................................
.............................................
Maintenance Pressure gauge
30 28
.............................................
..........................................
Purpose Gear
27 See Equipment
...................................................
..........................................
................................
...............................................
...........................................
Hypothermia
160
................................................
............................................
Gear bags
43
.....................................................
Giant stride entry Gloves
62
Purpose Selection Types Goggles
19 19 19 15
Goodie bag
44
............................................
Independent emergency ascents Indire Indirect ct effects effects of pressure Indirect pressure Ingassing nitrogen
79 116 116 124
Inhaling water Injuries Injuries,, lung overexpansion overexpansion
116 112
..........................
...................................................
..................................................
......................................................
.......................................................
...................................................
Great Lakes Lakes,, divin diving g
193
........................................
Gulf of Mexico, Mexico, diving diving
193
.....................................
................................
...........................................
........................................
..............................................
.............................
Instruments Backup Compass
....................................................
32 30
..................................................
Computers Depth gauge
H
31 28
................................................
.............................................
Hand signals
.................................................
Head Head cold, diving wit with h Head, thermal protection for
....................................
82
109 40
..............................
Health considerations Hearing under water
9 96
........................................
.......................................
Heat loss loss under water water Heatstroke Heat, effect of, on cylinders Hoods Hoses, regulator Human body Air expansion and Air in mask and Airspaces Avoiding squeezes squeezes Equalizing pressure pressure Indirect Indirect effects effects of pressure Lungs
..........................
96,119,160 l6l 23 40 25
Maintenance Submersible pressure gauge
32 28
.............................................
...........................
Timing devices devices Insulation Insulation,, heat loss and and
31 l6l
International dive flag In-water artificial respiration
43 168
..........................................
.................................
.....................................
............................
..................................................
................................
J
.........................................................
.............................................
.....................................
J va valve
.........................................................
Ja Jackets, buoyancy cont contro roll Jell Jellyf yfis ish h
22
34 172,187
.................................
112 Ill 104 107 108 116 112
...............................................
........................................
................................................
.....................................
...................................
...........................
....................................................
K K valve
22
.........................................................
Kicking Knives
50 42
........................................................
.........................................................
INDEX
Master scuba diver course Maximizing underwater time By limiting depth
199
................................
L
137
......................................
Lead weights
By limiting dive time By planning surface intervals
See Weights
..................................
......................................
Leadership courses Leg cramps Letter group group of NAUI NAUI dive table tables s
........................................
199 162 130
........................
137 137
Mediastinal emphysema Medical History form Methods of equaliz equalization ation
113 7,9 108
Micronesia, diving Middle ear Anatomy
193
Blocks Squeezes Monitoring air supply
109 107 106
Motion sickness Moving water, water, effect on divi diving ng
164 182
112 114
Multilevel dive Muscle cramps
142 162
Air embolism embolism
113
Definition
113
U
.................................................
.........................
Light, underwater Log mode of dive compu computer ter Logbooks Long-range dive dive plan planni ning ng
45 146 44,155 150
...........................................
..............................
...............................................
...............................
Longshore current
.........................................
184
Lost bu buddy pro proce cedu dure re.. .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... ...8 .81 1 Louisiana, diving Lubber line
193 30
...........................................
..................................................
Lungs Anatomy Breathing and circulation Overexpansion
................................................
............................
.........................................
..................................
......................................
...................................
.........................................
.................................................
107
....................................................
.................................................
.....................................
............................................
...........................
..............................................
..............................................
.............................................
Pneumothorax
.......................................
113
NAUI Advanced Scuba Scuba Diver
113
course NAUI Dive Dive Planni Planning ng Worksheet
Tissue emphysema
..................................
Lycra®
........................................................
38
................................................
7,198 132
..........................
NAUI dive table rules
......................................
NAUI dive table terms NAUII Dive Time Calculator NAU Calculator
M
128 127
......................................
Marine life Marker Marker buoy buoy Mask squeeze
..................................................
185 45 Ill
.................................................
...............................................
Masks Squeezes........... ...... ........... ............ ............ ........... ........... ............ .........I ...I l l Masks Breathing without Clearing Features Flooded, breathing with with
Dive planning
139
Organization
139
..........................................
...........................................
Using NAUI leadership courses NAUI Master Scuba Diver course course
139 199 7,199
NAUI specialty courses
7,199
....................................................
...................................
.....................
.................................
69 67 15 69
NAUI Train NAUI Training ing Assistant Assistant course course Navigation Compass Natural
Fogging Preparing for use
16 16
Purpose Removing and replacing
15 68
Selection
15
Negative buoyancy Neoprene Neoprene booties Neoprene gloves Neoprene prenewetsui wetsuits ts
.......................................
..................................................
...................................................
................................
...................................................
........................................
...................................................
...............................
..................................................
199
..........................
..................................................
...................................................
..........................................
88 87 99 17 17 19 38
......................................................
............................................
..............................................
...........................................
NAU I Scuba S cuba D i ver
Neutral buoyancy Nitrogen
74, 98
.......................................
Power inflator, inflator, buoyancy buoyancy compensator compensator
..................
Precautionary decompression stop Pregnancy and diving
.................
Composition in air
......................................
Ingassing
94
124
................................................
57
76,128 9
.......................................
Pressure Absolute
Offgassing
124
Residual
128
Air
117
Ambient Atmospheric
25 102
Blocks
107
...............................................
.................................................
Nitrogen narcosis
..........................................
Nitrox No-de No-decompression lim limit its s
95,118 125
No-decompression tabl tables es
127
...................................................
.................................
.................................
0
102
.................................................
101
........................................................
...................................................
.............................................
....................................................
Boyle's law Characteristics
103
Air Air Density Definition Effect
94 94 101
..............................................
.......................................................
..................................................
Octop Octopus method, sharing sharing air air by by
77 26 124
..........................
Octopus regulator Offgassing nitrogen
...........................................
........................................
...............................................
On airspaces On density On volume
.........................................
Omitted decompression Oral inflator, inflator, buoyancy buoyancy compensato compensator
139 33
Orientation, site
178
Equalization methods
Over heating Overexertion Overexpansion injuries
l6l 166 112
Overhead environment
177
Equalizing ears Fresh water Gauge, Gauge, submersible submersible Indirect effects Carbon monoxide toxicity
...................................
....................
............................................
................................................
................................................
...................................
....................................
Oxygen Oxygen toxicity
................................................
114,117 117
.............................................
............................................
...........................................
107 101 27, 28, 56
.........................................
..............................................
............................
Decompression sickness
Personal buoyancy Personal flotation Planning Site orientation
.....................................
155
97,98 19
...........................................
Ingassing and offgassing
116
Nitrogen narcosis
117
Oxygen toxicity Saltwater
................................................
Squeezes Units Volume relationships Pressure Pressure relief relief disk Problems Air starvation Choking and coughing Cramps Disorientation and vertigo Entanglements Equipment difficulties Heat loss Method Method of solving solving
178
Water temperature 181 Plannin Planning g worksheet worksheet See Dive planning planning wor worksh ksheet eet Plants, entanglement in 162 Plastic Plastic trash bag bags, s, conservation conservation and and 191 .....................................
..................................
....................
Pneumothorax Pony bottle Popular diving areas
113 27 192
Positive buoyancy Pounds Pounds per square square inch (ps (p si)
98 101
.............................................
...................................................
......................................
...........................................
............................
117 101 107 102 102 23
.................................................
.....................................................
..................................
........................................
116
............................
......................................
.........................................
118
..........................
....................................
Packing for a dive
107
.................................
..........................
P
106 104 102
..........................................
...........................................
...............................
..................................................
............................
.........................................
................................
165 164 162 163 162 163 160 160
.................................................
......................................
INDEX
Over heating Overexertion Seasickness PSI PS I
l6l 166 164 See Pounds per square inch (psi) (psi)
............................................
............................................
.............................................
......................
Purge button, regulator
...............................
30, 6 9
R
Reverse block
107
Rip currents Risks
183 7
...............................................
.................................................
............................................................
S Safety Air starvation and Aquatic life injuries Buddy system Choking under water Communication and
......................................
Rapture ture of th the de deep.... .. .... .... .... .... .... ..... ..... .... .... .... .... .... .... ..... ..... .... .... ..1 117 Rebound Rebound effect, effect, sinus block block and and 110 Recompression chamber 114,171 ........................
...........................
Recording dives Recreational depth limits Refraction of light under water
............................................
.................................
155 125 95
...........................
Regulators Alternate air air sources sources
....................................
115 171 80 164 82
.............................................
..................................
...................................
Coughing under water Cramps
164 162
Disorientation
163
................................
..................................................
..........................................
26
Diving situations
160
Annual service Blast clear Breathing from free-flowing Breathing underwater Breathing without a mask
31 6 9 70 6 9 6 9
Diving rescues Emergency ascents Entanglements
167 79 162
Clearing Exhaling Exhaling when out of mouth
6 9 6 9
First stage Maintenance Octopus regulator Position of alternate mouthpiece
25 30 26 26
Purge clear
69 25
....................................
...........................................
................................................
...........................
..................................
.............................
..................................................
.........................
................................................
.............................................
.......................................
.....................
...............................................
Purpose Recovering
...................................................
.......................................
..........................................
......................................
.........................................
Equipment difficulties
................................
163
First aid 169 Hand sig sign nals and...... and......... ...... ...... ...... ....... ....... ...... ...... ...... ....... ......8 ..82 2 Helping other divers 165 In-water artificial respiration 168 .............................................
..............................
........................
Lost buddy buddy procedure procedure
81,153
Planning for Planning your dive Respon Responsible sible scuba diving practices practices Seasickness
153,172 150 172 164
..........................
....................................
....................................
..................
..............................................
Sharing air Site orientation Skills
77 178 77
...............................................
Sweep Reach
6 9 70 26 131 135 138 167 126 97 168 210 201,211
...................................................
..................................................
Second stage Repetitive Dive timetable Repetitive dives, time limits for Required decompression decompression
.............................................
.................................
.........................
..................................
Rescues, diving Residual nitrogen Resistance of the water Respiration, artificial, in-water Responsible boat diving Responsible Responsible scuba scuba diving diving
.............................................
..........................................
.....................................
..........................
..................................
..........................
........................................
......................................................
Solving problems 160 Sound signals and and 82 Unconscious diver 167 Safety stop See Precau Precaution tionary ary decompression stop ......................................
......................................
......................................
Saliva Saliva,, and mask mask fogging Saltwater pressure pressure Scrolling, dive computer Scuba certification Scuba diving Apprehension
.......................
16,48,120 101 144 5
.........................................
..................................
...........................................
..............................................
8
NAU I Scuba D i ver
Fitness Health
......................................................
......................................................
9 9
Misconceptions
8
Risks
7
............................................
........................................................
Use Use of drugs drugs and alco alcoho holl Your obligations
...............................
10 9
..........................................
Scuba tanks
.....................................
See Cylinders
Sea Sea urchin urchin
171
..................................................
Blast clearing
6 9 54
Regulator Snorkel
..............................................
.................................................
Boat and platform Entries Exits Buddy system
62 65 80
Buoyancy Checking equipment Communication
73 6l 82
..................................................
.....................................................
.............................................
.................................................
SEABAG BAG steps
6l
Checklist
212
Disassembling scuba unit
SEA steps
153
Displacement clearing of snorkel
Seasickness Seated side entry entry
164 63
Donning
....................................
.................................................
................................................
................................................
.................................................
.............................................
Senses, effects of diving on Shallow breathing
..........................
95,163 115
.........................................
Shallow water blackout
.........................................
54
.....................
Gear Scuba unit Weight belt
.....................................................
.............................................
.............................................
59
77
Emergency ascents Entering and exiting the water
79 6l
Giant stride entry
62
...................................
......................................
Octopus method Shark attack, threat of
77 8,185
.........................................
................................ ................................
Shipwrecks, conservation of
.............................. ..............................
Shivering, heat loss and Shoreline conditions
190 96
....................................
......................................
178
Shorty wetsuits Shot pouches
39 36
...............................................
................................................
59 60
Donning diving suits
Sharing air ..............................
49
54
.....................................
Buddy breathing method
89
..............................
.......................
.......................................
Handling scuba unit in the water
85
Ladder exits Mask
65
....................
..............................................
Clearing Removing and replacing
67 68
................................................
............................
Monitoring air supply
............................
72,106
Single dive, time limits for................................125
Navigation
87
Sinuses Anatomy
110
Block
110
Orally inflating BC Purge clearing of regulator Regulator recovery
71 6 9 69
Removing and replacing replacing weight belt in water
86
Safety Seated side entry
77 63
Sharing air Snorkeling
77 48
...............................................
......................................
................................................
.....................................................
Medication Squeezes Site orientation
Ill 110 178
Site survey Six-pack Six-pack plastic rings, cu cutting tting open Skills Assembling scuba unit
153 190
..............................................
................................................
.............................................
...................................................
....................
.................................
...........................................
......................................
...........................................
.....................................................
.........................................
...............................................
...............................................
55
.................................
Assembling weight weight bel beltt Back roll entry Beach Entries Exits
...........................
58 63
Surface dives Swim platform exits Switching from regulator to snorkel Testing scuba unit Using Using fins fins
....................................
.................
......................................
64 66
..................................................
.....................................................
52 65 71 57 50
.............................................
................................................
Skin diving
...............................................
5,53
INDEX
Skip breathing Slate, underwater Sneezing
.............................................
115 44 116
Surface dives Feet first
....................................................
Snorkeling vest
Snorkels Blast clearing Displacement clearing
Head first
52
Pike
52
.................................................
19
..............................................
53
...................................................
............................................
........................................................
Tuck
.......................................................
54 54
Surface flotation
Surface Interval Time (SIT) table
128
16 16 17 48
Surface intervals, dive planning
136
Surge
182
............................................
.................................
Features Purpose Selecting Using
...................................................
...................................................
..................................................
.....................................................
52 72
.............................................
.......................
.........................
.........................................................
Swells
........................................................
182
Swimming Swimming pool, pool, learning diving skills in
................
Sound signals Sound, transmission of
82 96
Spare parts Special Special dive table table rules
45
...............................................
.................................... ....................................
...................................................
9
T Tanks
See Cylinders
.............................................
Altitude diving Cold or strenuous dives
139 139
Decompression Flying after diving Omitted decompression
137 139 138
..........................................
...............................
.........................................
.....................................
...............................
Required decompression Specialty courses Spined marine life
..............................
...........................................
.........................................
138 198 186
..............................................
5
Temperature Core body
.................................................
Water
....................................................
37
181
Terrain, underwater
179
Texas, diving
193
.......................................
...............................................
Thermal effects of diving
119,160
...........................
Thermal Thermal protection
37
Sport diver's flag Squeezes Definition Dry suit Mask space
107 Ill Ill
Tidal currents
184
Tides
183
Middle ear Sinuses
107 110
Tissue emphysema
............................................
43
Technical diving
.........................................
Thermocline
181
................................................
...............................................
..................................................
.............................................
..............................................
...................................................
Teeth Standing current Starvation, air Steel cylinders Stinging marine life Stingray Streamlining, reduction reduction of drag drag by Strenuous dives, dives, rules for for Stroke, heat Subcutaneous Subcutaneous emphysema Submersible Submersible pressure gauge gauge Surf
Ill 184 115 20 187 186 97 139 l6l 114 23, 56,72 56,72 182
.....................................................
..........................................
..............................................
................................................
.......................................
.....................................................
......................
.................................
.................................................
...............................
.....................
.......................................................... ..........................................................
..............................................
..........................................................
Timing devices
..............................................
31
113
.........................................
Total nitrog nitrogen en time (TN (TN T)
128
Toxins
186
...............................
.......................................................
Training assistant specialty course
199
Transitory currents
184
......................
........................................
Trap door effect, Eustachia Eustachian n tube and Trash, conservation and
107 190
..................
..................................
Trim, gear and
..............................................
Truk Lagoon, diving
......................................
33
193
Turks & Caicos, Caicos, diving diving
193
Types of dive sites sites
176
....................................
..........................................
NA UI Scuba Sc uba D i ver
Getting in and out of
u
6l
................................... ...................................
Handling equipment in
Unconscious diver
Inhaling, effects of
..................................... .....................................
At the surface surface
167
...........................................
Under Under water water Underwater communication
16.8 82
.............................................
..............................
Underwater hunters, conservation and an d Underwater light
.................
189 45
.............................................
Underwater navigation Underwate Underwaterr slate slate
.....................................
Pressure, Pressure, physical physical effects effects of of
.......................... ..........................
Water conditions
...........................................
180
Waves
182
........................................................
Weights
87 44
Assemb Assembling ling weight bel beltt
58
Belts
36
.................................
.......................................................
39 102 125
......................................
104 181
.........................................
Donning Donning weight weight belt belt
.........................................
...........................................
164
Water temperature
.............................................
Underwe Underwear, ar, dry su suit Units of pressure U.S. Navy dive tables
85
................................
....................................
Harnesses
36
.................................................
Keepers
60
36,59 36
................................................
Purpose
...................................................
V
Quick release
37
.............................................
Removing and replacing weight Valves
belt belt in water water
86
...........................................
DIN type
..................................................
23
Systems
36
Types
36
...................................................
J ty type K type
......................................................
.....................................................
Purpose
...................................................
Vertigo Vest, snorkeling
.................................................
22 22 23
......................................................
Wetsuits Choosing based on conditions.........................41
107,163 19
Maintenance
42
Operation
38
Options
39
Styles
39
.............................................
..............................................
.................................................
Visibility Vision under water
180 95
Visual Inspection
23
.....................................................
...................................................
..........................................
............................................
......................................................
Thicknesses
..............................................
Volume Closed system Open system system
103 102
...........................................
............................................
Pressure effects
.........................................
102
Women, effects of diving on
39
.................................
Worksheet
....................
9
See Dive planning worksheet
Wrecks, exploring
..........................................
190
Y
W Waiver and release form
....................................
Watch, diving Water Clearing
................................................
From mask From regulator From snorkel
7
31
67 69 54
.............................................
.......................................
..........................................
Density and buoyancy Entries and exits
..................................
.........................................
97 6l
Yoke, regulator
.....................................
22,25, 56
