UKOOA Guidelines for Ship/Installation Collision Avoidance Issue 1 February 2003
UK Offshore Operators Association
Guidelines for
SHIP/INSTALLATION COLLISION AVOIDANCE
ISSUE 1 FEBRUARY 2003
Whilst every effort has been made to ensure the accuracy of the information contained in this publication, neither UKOOA, nor any of its members will assume liability for any use made thereof. All rights reserved. No part of this publication may be reproduced, stored in a retrieval system, or transmitted in any form or by any means, electronic, mechanical, photocopying, recording or otherwise, without prior written permission of the publishers. Crown copyright material is reproduced with the permission of the Controller of Her Majesty’s Stationery Office. Copyright 2003 UK Offshore Operators Association Limited Limited
Guidelines for
SHIP/INSTALLATION COLLISION AVOIDANCE
ISSUE 1 FEBRUARY 2003
Whilst every effort has been made to ensure the accuracy of the information contained in this publication, neither UKOOA, nor any of its members will assume liability for any use made thereof. All rights reserved. No part of this publication may be reproduced, stored in a retrieval system, or transmitted in any form or by any means, electronic, mechanical, photocopying, recording or otherwise, without prior written permission of the publishers. Crown copyright material is reproduced with the permission of the Controller of Her Majesty’s Stationery Office. Copyright 2003 UK Offshore Operators Association Limited Limited
ISBN: 1 903003 20 2 PUBLISHED BY UK OFFSHORE OPERATORS ASSOCIATION London Office: 2nd Floor, 232-242 Vauxhall Bridge Road, London, SW1V 1AU. Tel: 020 7802 2400 2400 Fax: 020 7802 2401 Aberdeen Office: 9, Albyn Terrace, Aberdeen, AB10 1YP Tel: 01224 626652 Fax: 01224 626503 Email:
[email protected] Website: www.oilandgas.org.uk
Ship/Installation Collision Avoidance Avoidance
CONTENTS Page No INTRODUCTION
iii
Purpose and Scope
iii
Contributing Organisations
iv
ABBREVIATIONS
vii
1
2
3
4
COLLISION RISK MANAGEMENT SYSTEM
1
1 .1
Introduction
1
1.2
Responsibilities
1
1 .3
Key Elements
2
BACKGROUND AND OVERVIEW
8
2 .1
Introduction
8
2.2
Probability of Collision
8
2.3
Passing Vessels
9
2.4
At Attendant Vessels
10
2.5
Offtake Tankers
10
2.6
Contingency Planning and Procedures
12
2.7
Incident and Near Miss Reporting
14
2.8
Reporting and Follow-up
15
2 .9
Auditing
16
2.10 Performance Standards
16
PASSING VESSELS
17
3 .1
Introduction
17
3.2
Assessing the Potential for Collision
18
3 .3
Minimising the Probability of Collision
20
3 .4
Collision Avoidance Measures
21
ATTENDANT VESSELS
26
4 .1
Introduction
26
4.2
Assessing the Potential for Collision
27
4 .3
Minimising the Probability of Collision
28
4 .4
Collision Avoidance Measures
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4.5
Contingency Plans
34
4.6
Follow-up
34
OFFTAKE TANKERS
35
5.1
Introduction
35
5.2
Assessing the Potential for Collision
35
5.3
Minimising the Probability of Collision
36
5.4
Collision Avoidance Measures
39
Figures Figure 1
Key Elements of Successful Health and Safety Management
2
Figure 2
Collision Risk Management – Summary Flowchart
5
Figure 3
Collision Avoidance Flowchart
6
Figure 4
Collision Avoidance Procedures – Passing Vessels
7
Addendum 1
Glossary of Terms
2
Promulgation and Detection – Passing Vessels
3
Systems Audits
4
Vessel Suitability and Inspection Formats
5
Field Checklist
6
Installation Data Cards
7
Incident and Near Miss Reporting Formats
8
References Including Relevant Codes and Regulations
9
Passing Vessel – Ship Collision Assessment
10
Vessel Impacts – Guidance on Loads and Consequences
11
Contacts
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INTRODUCTION Purpose and Scope This document gives guidance to Dutyholders on reducing the probability of collisions between vessels and offshore Installations. It has been developed by United Kingdom Offshore Operators Association (UKOOA), supported by the Health and Safety Executive and with the assistance of other stakeholders. Various accident types involving serious injury or loss of life, or which have the potential to do so, are defined as ‘major accidents’ under the Safety Case Regulations (SCRs). SCRs define ‘major accidents’ as: a.
Fire, explosion or the release of a dangerous substance involving death or serious personal injury to persons on the Installation or engaged in an activity on or in connection with it.
b.
Any event involving major damage to the structure of the Installation or plant affixed thereto or any loss of stability of the Installation.
c.
The collision of a helicopter with the Installation.
d.
The failure of life support systems for diving operations in connection with the Installation, the detachment of a diving bell used for such operations or the trapping of a diver in a diving bell or other subsea chamber used for such operations.
e.
Any other event arising from work activity involving death or serious personal injury to five or more persons on the Installation or engaged in an activity in connection with it.
Regulations 8(1) (c) and (d) of SCR requires that a Dutyholder demonstrates in their Safety Case that all hazards with the potential to cause a major accident have been identified, that the risks have been evaluated and that measures have been or will be taken to reduce the risk to people to As Low As Reasonably Practicable (ALARP). The ‘major accident’ definition (b) in the above Regulations includes impacts from both infield (attendant) and passing vessels as events likely to involve major damage to the structure of the Installation. Consequently, all types of vessels with the potential to impact the Installation must be considered as a Major Accident Hazard (MAH) under SCR.
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SCR are complemented by Prevention of Fire and Explosion, and Emergency Response (PFEER) Regulations. PFEER requires the Dutyholder to assess MAHs that may require Evacuation, Escape and Rescue (EER) and to identify appropriate arrangements for dealing with them. Such arrangements will include preparation for emergencies, an emergency response plan, detection of incidents, communications, control of emergencies, muster areas, arrangements for evacuation, means of escape and arrangements for rescue and recovery. This guide focuses on the avoidance of ship/Installation collisions. Although the concepts of risk and ALARP are referred to within the document, it is not intended to provide detailed assessment of consequences of a collision. Similarly only key considerations in the development of appropriate collision response strategies are provided. Hence, the guidance draws together and summarises current best practice on avoiding collisions between vessels and Installations. For convenience it addresses separately: •
Passing vessels – those en route to somewhere else
•
Attendant vessels are vessels with legitimate business at the Installation
•
Offtake tankers, a subset of attendant vessels, which interact with the Installation in a specialised way and are therefore addressed in a dedicated section
Recommendations made in this guide rely principally on checklists covering management systems, vessel suitability, self-audit and pre-operational checks (a form of risk assessment). They draw, wherever possible, on existing proven industry standards. The guide is aimed principally at operations in the United Kingdom (UK) sector, and therefore refers to UK legislation, practices and organisations. Other administrations and national associations may wish to adapt the principles to their own sectors.
Contributing Organisations The following organisations have been consulted in developing this guide:
iv
•
Health and Safety Executive
•
Maritime and Coastguard Agency (MCA)
•
Trade Unions: National Union of Marine Aviation and Shipping Officers (NUMAST) and Rail, Maritime and Transport Union (RMT)
•
UKOOA Marine, Hazard Management, Structural and Floating Production, Storage and Offtake (FPSO) unit Committees
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•
International Marine Contractors Association (IMCA)
•
Emergency Rescue and Recovery Vessel Owners Association (ERRVA)
•
Chamber of Shipping
•
Marine Safety Forum
•
Intertanko
•
Oil Companies International Marine Forum (OCIMF)
•
International Association of Drilling Contractors (IADC)
•
British Rig Owners Association (BROA)
•
Scottish Fishermen’s Federation (SFF)
•
Step Change in Safety
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ABBREVIATIONS AHTS AIS ALARP ARCS
Anchor Handling Tug Supply Automatic Identification of Ships (IMO Resolution 22/9 Annex II) As Low As Reasonably Practical Admiralty Raster Charting Service
BPD BROA
Barrels (oil production) Per Day British Rig Owners Association
CMID CPA CRM
Common Marine Inspection Document Closest Point of Approach Collision Risk Management
DCR
Offshore Installations and Wells (Design and Construction, etc) Regulations SI 913 1996 Det Norske Veritas Dynamic Positioning (or Dynamically Positioned) Digital Selective Calling Department of Transport, Local Government and The Regions (formerly DETR)
DNN DP DSC DTLR
EER ERRV
ESD
Evacuation, Escape and Recovery Emergency Rescue and Recovery Vessel (formerly Standby Vessel) Emergency Rescue and Recovery Vessel Owners Association Emergency Shutdown
FMEA FPSO FSO FSU
Failure Mode and Effect Analysis Floating Production Storage and Offtake Unit Floating Storage and Offtake Unit Floating Storage Unit
GMDSS GPS
Global Maritime Distress and Safety System Global (Satellite) Positioning System
HSE HS(G) 65 HSWA
Health and Safety Executive Successful Health and Safety Management Health and Safety at Work Act 1974
IADC IMCA IMO ISM
International Association of Drilling Contractors International Marine Contractors Association International Maritime Organisation International Safety Management Code
JOP
Joint Operating Procedure
ERRVA
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KIS
Kingfisher Information Services
LMIS LSA
Lloyds Maritime Information Services Low Specific Activity
MAR MAH MCA MoD
Management and Administration Regulations Major Accident Hazard Maritime and Coastguard Agency Ministry of Defence
NUI NUMAST
Normally Unattended Installation National Union of Marine Aviation and Shipping Transport Officers
OCIMF OIM OSV OSV Code
Oil Companies International Marine Forum Offshore Installation Manager Offshore Support Vessel Guidelines for the Safe Management and Operation of Offshore Support Vessels Offshore Technology Report (O)
OTO PFEER
Prevention of Fire and Explosion and Emergency Response Regulations SI 743 1995
RIDDOR
Reporting of Injury Death and Dangerous Occurrences Regulations SI 3136 1995 Rail, Maritime and Transport Union
RMT SBV SBV Guidelines
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SCR SPM
Standby Vessel (See ERRV) Guidelines for the Safe Management and Operation of Vessels Standing By Offshore Installations Safety Case Regulations SI 1992/2885 Single Point Mooring
TAV TLP TR
Towing Assist Vessel Tension Leg Platform Temporary Refuge
UK UKCS UKHO UKOOA
United Kingdom United Kingdom Contential Shelf United Kingdom Hydrographic Office United Kingdom Offshore Operators Association
VHF
Very High Frequency
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COLLISION RISK MANAGEMENT SYSTEM 1.1 Introduction This section is included to give an overview of the systems required for ship/Installation collision avoidance. It sets avoidance of collisions in overall context of the Dutyholder’s Health, Safety and Environmental management systems. For further guidance on Collision Risk Management (CRM) consult ‘Effective Collision Risk Management’ for Offshore Installations, Offshore Technology Report (OTO) 1999 052, Health and Safety Executive January 2000.
1.2 Responsibilities Overall responsibility for safe operations within the Safety Zone of any offshore Installation lies with the Offshore Installation Manager (OIM). The Dutyholder and the Installation management are responsible for implementing and maintaining a CRM system appropriate to the Installation and its particular location. This system should include: •
Management commitment to ongoing and effective CRM
•
Clear policies
•
Assessment of the probability of collision peculiar to the Installation and location
•
Provision of necessary risk reduction and control measures
•
Appropriate procedures and communications for managing attendant vessels
•
Ensuring the suitability of attendant vessels and the competence of their crews, including their ability to implement CRM requirements
•
Provision of appropriate equipment and procedures for detecting and assessing the actions of passing vessels
•
Provision of adequate competent Installation personnel with an appropriate level of marine knowledge
•
Provision of appropriate evacuation and rescue procedures and facilities
•
An effective reporting and feedback system
•
Regular audit and updating of the system
If applicable, the Dutyholder must ensure that any offtake tankers are suitable for the particular operation and that crews are both adequate and competent for the peculiarities of the operations at that particular field. Offtake operations should be covered by field/vessel-specific Joint Operating Procedures (JOPs).
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Masters of passing vessels are responsible for the safe operation of their vessels and for collision avoidance. They are excluded from Installation Safety Zones but Dutyholders have limited ability to enforce this. Masters of attendant vessels should comply with the reasonable instructions of the OIM when within a Safety Zone. Although they remain responsible for the safety of their crew, the safe operation of their vessel and for collision avoidance. The master of an offtake tanker is similarly responsible for the safety of personnel, for the safe operation of his vessel and for avoiding contact/collision with the Installation or associated facilities.
1.3 Key Elements The diagram below is taken from Successful Health and Safety Management (HS(G)65) whose principles apply equally to CRM.
Policy
Organising
Auditing
Planning & Implementation
Measuring Performance
Reviewing Performance
Figure 1 Key Elements of Successful Health and Safety Management
Therefore the Dutyholder should have in place a CRM system as outlined in the following paragraphs.
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1.3.1
Management Systems
1.
Include clear corporate policies.
2.
Contain clearly stated and understood goals and objectives including a hierarchy of measures to achieve those objectives.
3.
Demonstrate senior management commitment to effective CRM.
4.
Define responsibilities for CRM.
5.
Ensure the adequacy and competence of specialist personnel.
6.
Ensure the suitability of any support vessels required to implement CRM.
7.
Ensure that contractors operate to the same standards.
8.
Contain procedures for detecting, assessing and managing any potential collision appropriate to the risks of the particular Installation and location.
9.
Audited at regular and appropriate intervals with independent feedback to senior management on the effectiveness of the system.
1.3.2
Personnel Policies and Procedures
1.
Clearly understood responsibilities for implementing and maintaining the system.
2.
Clearly stated policies.
3.
A safety organisation such that management have access to competent persons with the necessary expertise.
4.
Means of ensuring the competency of personnel involved in CRM (including Installation, attendant vessel and other contractor personnel).
5.
Means of ensuring that when personnel change, the same level of competency and knowledge continues.
1.3.3
Attendant Vessel (Including Offtake Tanker) Procedures
1.
Procedures for ensuring that the vessels and their critical systems are fit-for-purpose.
2.
Means of ensuring that vessels which operate in close proximity to Installations are manned by sufficient and competent persons.
3.
A culture which reinforces these procedures by communications and follows up on incidents and near misses.
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maintaining
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1.3.4
1.
Means of detecting, anticipating and assessing a hazardous situation that are appropriate to the level of risk.
2.
Adequate communications to deal with the situation and to mitigate those risks.
3.
Well practiced procedures for dealing with the consequences and providing a good prospect of rescue and recovery.
4.
Any required detection/assessment systems maintained as safety critical.
1.3.5
4
Passing Vessel Policy and Procedures
Risk Assessment and Performance Measurement
1.
Structured identification and assessment of hazards.
2.
Appropriate risk reduction and control measures.
3.
A mean of monitoring performance against those standards.
4.
A system for recording incidents and near misses, identifying trends and feeding back to the CRM system.
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Management Commitment
Clear Policies
Risk Assessment
Installation Design, Impact Resistance
Promulgation of Location
Collision Avoidance Procedures
Support Vessel Selection Management
Contingency Plans Including Evacuation, Escape and Recovery (EER)
Consequences Planning
Reporting, Implementation, Measuring and Reviewing Performance
Audit
Figure 2 Collision Risk Management – Summary Flowchart
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Assess Collision Probability
ttendant Vessels Incuding Offtake Tankers
Clear Policies Passing Vessels
Installation Vulnerability
Installation Location
Vessel Suitability and Manning
Promulgation and Charting
Crew Competence
Detection and Communications
Installation Marine Knowledge
Procedures and Checklists
Assessment of Threat
Contingency Plans
Near Miss Reporting
Analysis and Follow-up
Figure 3 Collision Avoidance Flowchart
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Passing traffic and collision frequency assessed Location of Installation well promulgated Responsibility for surveillance clearly understood Detection and communications equipment suitable, crew trained, proper maintenance Regular exercises and drills
Detection and Assessment
Detection range and Closest Point of Approach (CPA) threshold a reed Blind sectors covered during close standby Time to CPA for first alert 24-hour communications with control room/OIM Communications with approaching vessel Times to CPA for subsequent alerts
Pre-planned Actions
Support vessel communications/actions Installation actions/musters Identify point of impact and useable Low Specific Activity (LSA) Short notice response/evacuation Collect and record evidence
Follow-up
EER procedures including vessel crews Communications Reporting
Warning off Near Miss Safety Zone infringement Incident/collision Prosecution Closeout
Report to Installation/vessel personnel and industry
Figure 4 Collision Avoidance Procedures – Passing Vessels
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2
BACKGROUND AND OVERVIEW 2.1 Introduction From the Health and Safety Executive Collision Risk Database (1997) (OTO 1999 080), it is apparent that some 500 ships have collided with offshore Installations in the UK sector between 1975 and 2000. Over 96% of the collisions have involved attendant vessels (those with legitimate business at the Installation). The number of near misses is likely to have been considerably higher. About 20% of the reported incidents caused moderate or severe damage. To date in the UK sector there have been no collisions which caused catastrophic damage or loss of life. However, worldwide there have been a number of collisions which caused total loss of the Installation. The database prompted the Health and Safety Executive to commission a study ‘Effective Collision Risk Management’ (OTO 1999 052) which reviewed and summarised collision data for the United Kingdom Continental Shelf (UKCS). By its nature the offshore oil and gas industry requires marine support, hence it is necessary for vessels to approach and work in close proximity to the Installation. The increasing use of floating production/storage systems and tanker offtake, introduces close proximity work with large vessels carrying hazardous cargoes. Many of the UK’s oil and gas fields are in busy traffic areas and virtually all experience some passing marine traffic, albeit rare in more remote regions. Under the Safety Case Regulations (SCR), ship collision is considered a Major Accident Hazard (MAH).
2.2 Probability of Collision Risk can be defined as the product of the likelihood of experiencing a collision and the potential consequences. The risk is then managed to acceptable levels, under the As Low As Reasonably Practical (ALARP) principle, by mitigation and control measures, including prevention, detection and emergency response. This document does not deal in detail with the consequences. It concentrates on best practice in reducing the probability of a vessel/Installation collisions. In general, a vessel/Istallation collision is reasonably foreseeable. Historically, the probability of an attendant vessel colliding with the Installation is nearly two orders of magnitude greater than a passing vessel collision. The impact energy from an attendant vessel collision is likely to be low, except in the case of a shuttle tanker/Floating Production Storage and Offtake (FPSO) unit collision. Although the probability of a passing vessel collision is low, the impact energy could be high. In all cases, catastrophic consequences in terms of loss of life, environmental impact and business risk are reasonably foreseeable. For attendant vessels, probability of collision increases with the number of Installation visits, by holding station in close proximity and for example weather side working.
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Controls include: •
Minimising the number of visits
•
Adjusting working and standby locations
•
Vessel vetting
•
Effective procedures
Human factors are undoubtedly relevant when working very close to an Installation. For passing vessels the Installation management has fewer options. The risks can be assessed according to volume and type of marine traffic. When a relatively high probability of collision exists, then risk reduction measures will concentrate on promulgating the location widely in the shipping community, on effective detection, intervention by the emergency rescue and response provider or vessel and on good communications. Awareness, procedures and effective escape and rescue provisions will mitigate the consequences. Appropriate siting and protection of vulnerable areas such as risers and accommodation and resilience of the overall structure can also mitigate the effects.
2.3 Passing Vessels Less than 4% of the collisions reported in the vessel/Installation Collision Risk Database were caused by passing vessels (vessels bound somewhere else). The vessels involved were generally small, principally fishing vessels, although some collisions caused severe damage. A passing vessel is likely to be travelling at sufficient speed for impact energy to be significant, even if the vessel is relatively small. The incidence of passing vessel collisions shows no discernable trends, occurring spasmodically throughout the period of the survey. The study estimated that a passing vessel collision was likely to occur in the UK sector about once every two years. As shipping on passage is usually outside the influence of Installation management, effective controls are very limited. However, collision is reasonably foreseeable with the possibility of catastrophic loss. SCRs and PFEER (refer to Addendum 8) require the Dutyholder to take reasonable steps to manage the risk. The Dutyholder and the Installation management are responsible for providing an effective system for detecting and responding to the threat from an errant vessel. In all but a few cases, detection is carried out by the ERRV and its crew reporting to the OIM. That vessel and its personnel must therefore be given clear guidance on what is expected of them. They must have the capability, equipment, knowledge and competence to meet those expectations.
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2.4 Attendant Vessels The database shows that over 96% of vessel/Installation collisions in the UK sector involve vessels with legitimate business there. Although the majority are low energy collisions, attendant vessels caused about 10 times more moderate/severe collisions than passing vessels. Over the period of the study, frequency of such collisions has reduced. This may be due to improved marine expertise, better control systems and better understanding of the causes. The authors of the study suggested that improvements may be as a result of an effective management system. The report estimates that, based upon 1997 frequencies, 30 of the approximately 200 Installations in the UK sector were likely to experience a collision each year. Although 83% of attendant vessel collisions caused only minor damage, 3% had severe consequences. With the steady progress to larger and more powerful support vessels, the potential impact energy and resultant seriousness of the collision increases.
2.5 Offtake Tankers Improvements in offshore technology has accelerated the development of marginal offshore oil fields in North West Europe and worldwide. Much of this has been made possible by floating production systems. Although some are connected to pipelines, economics tend to favour tanker offtake. Most involve marginal fields, but some large assets with fixed Installations have used tanker offtake since inception. In the North Sea, offshore crude oil offtake has increased from 36% of total production in 1995 to 47% in 2000. United Kingdom Offshore Operators Association (UKOOA) estimate United Kingdom (UK) floating production and offtake at around 1.5 million bpd in 2010 and 1.0 million bpd in 2020. Some 240 developments are likely to come forward in the UK sector for approval in the next 25 years, the majority of which will use this method for exporting produced crude oil. Tanker offtake involves relatively large vessels, carrying hazardous cargo, manoeuvring in a congested oil field. Loading buoys are used in some fields. In others the offtake tanker moors to another floating vessel and is connected to it by hose. Thereafter, it must maintain station and alignment relative to the other vessel during the cargo transfer operation. Hence, the potential for collision occurs during approach, cargo transfer and departure. A high standard of vigilance is required throughout these operations. Some operations use a towing vessel to assist with mooring and stationkeeping. Whilst this reduces the probability of collision once in the towing mode, it does introduce a third vessel into the manoeuvres. Overall, the worst case consequences of a collision can be catastrophic in terms of loss of life, environmental damage and business risk.
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IMCA Report M150 on Shuttle Tanker Collisions published in February 1999 reviews the causes and estimates frequency of offtaker collisions with loading buoys and with storage vessels. It differentiates between Dynamic Positioning (DP) and non-DP offtakers. It notes a significant proportion of under-reporting, but that reporting improves after an incident. The non-DP data set is much smaller than the DP set. The main points are: •
156 incidents were analysed over the period from 1979 to 1998
•
Of these 12 resulted in collision between the tanker and loading point
•
The 12 collisions involved DP offtakers, but the non-DP set includes several instances of very high hawser tension (effectively a near miss)
•
Estimated frequency of major incidents
•
DP offtakers once in 20,000 offtake hours
• •
Non-DP once in 5,400 offtake hours Frequency of other incidents, including non-critical loss of position: – DP offtakers once in 2000 offtake hours – Non-DP once in 735 offtake hours
The report estimates that a typical DP offtaker could be involved in a loading point collision once in about ten years. Allowing for under-reporting, it also estimates that the typical tanker could be involved in a stationkeeping incident about 7 times per year. Principle causes of the collisions are grouped as: •
Position references faults
•
Main engine problems
•
DP operator errors
Collisions in offtake operations are foreseeable, hence Dutyholders must use their influence to manage the operation. Controls will include management commitment, operating practices and procedures, weather thresholds, vessel selection, Installation and vessel personnel competence, non-use of certain vessels and cessation of part or all the operation.
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2.6 Contingency Planning and Procedures 2.6.1
General
Each Installation will have emergency procedures for actions in the case of a major accident. This guide is concerned principally with avoiding vessel/Installation collisions and with the immediate actions following of any such collision. Emergency procedures will contain actions in case of a vessel collision and should reflect the very short notice which may be available for actions and evacuation. Contingency procedures for vessel collisions are essential and should be activated from the time that a threat of collision, from either an attendant or passing vessel, is detected. Effective procedures must be in place to ensure that the threat is detected as early as possible and that the resultant actions follow a well thought through and exercised path. It is essential that collision avoidance contingency plans and procedures are exercised frequently and regularly. Regular and relief support vessels likely to be on location must be involved in these exercises. In areas where the probability of a collision is low, exercises are just as important as in high probability areas. Both Installation and support vessel personnel will have to respond rapidly to an unusual event. 2.6.2
Passing Vessels
Contingency plans should include: •
Responsibilities for detection, communication and assessment of the threat
•
Time to possible impact for alerting the Installation to the threat
•
Time to possible impact for initiating shutdown of plant and evacuation
•
The decision points and actions for a controlled shutdown and evacuation in the case of drifting vessel threat
•
Actions of attendant vessel(s) in case of imminent threat
•
Different actions and timescales depending on whether the vessel is under power or drifting
Simple and concise procedures should include the distance/time at which a vessel is identified as a threat, the time at which the Installation is alerted and the process whereby the OIM and attendant vessel master monitor and assess the threat. Responsibilities of key personnel should be clearly identified.
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2.6.3
Attendant Vessels
An attendant vessel collision may impart sufficient energy to cause severe damage to the structure of the Installation and to itself. Hence contingency plans should consider: •
Attendant vessel loss of propulsion or control
•
Attendant vessel colliding with Installation at high speed
•
Attendant vessel adrift in close proximity
•
Rapid evacuation of the Installation personnel
•
Rescue of the attendant vessel crew, if needed
•
Fire and/or explosion
•
Shutting down production and/or pipelines
2.6.4
Offtake Tankers
Each field/Installation OIM should have available a standard contingency plan which can be adapted to particular offtakers in consultation with the master. In amplification of the attendant vessels procedures above, it should address: •
Significant offtaker propulsion or control problem during approach
•
Loss of position control at any time during the transfer operation
•
Offtaker adrift, out of control, in the field
•
Loss of or high mooring tension
•
Collision or close quarters event between offtaker and FPSO
•
Abort parameters
•
Significant offtaker propulsion or control problem during departure
•
Fire and/or explosion
•
Support vessel casualty
Offtaker specific plans should be held by both units and confirmed by checklist before each operation. Elements of the plan should be exercised periodically with dedicated offtakers.
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2.6.5
Evacuation Procedures
The evacuation plan will be part of the Installation’s emergency procedures. This document does not attempt to cover the subject comprehensively, merely to highlight special factors in dealing with the immediate actions required following a collision: •
Rapid decisions on muster points away from the likely point of impact
•
Using lifeboats/liferafts away from the point of collision
•
Use of helicopters if available
•
Making sure that lifejackets and/or immersion suits are readily available to personnel at all times
•
Evacuating enclosed spaces (including Temporary Refuge (TR) and control rooms) rapidly, using alternative muster points on deck
•
Rescuing a number of individuals from the water
Also refer to: •
Standby Vessel (SBV) Operating Guidelines Appendix 2 on evacuations and escape planning
•
Evacuation, Escape and Rescue (EER) guidance in the SCR (SI 1992/2885)
•
Management of Emergency Response for Offshore Installations (UKOOA)
2.7 Incident and Near Miss Reporting The studies referenced above accept a degree of under-reporting of incidents. Neither contain systematic reporting of near misses although some are included. Some models predict the number of near misses to be one to two orders of magnitude greater than reported incidents. Hence, the potential for vessel/Installation collisions in the UK sector is probably much greater than the 500 or so collisions reported for the North Sea oil and gas province in the 25-year period reviewed. Incidents in this context are easy to define eg a collision which actually occurred. A near miss is more subjective, generally circumstances which could escalate into an incident. Broad definitions are given in the Glossary of Terms in Addendum 1. Risk assessment techniques can predict the likely collision frequency but a structured incident and near miss reporting system will identify trends and allow further controls to be implemented. There is no sector-wide system in place but Health and Safety Executive collate both collision reports and available near miss data as part of the vessel/Installation Collision Risk Database.
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Near miss reporting systems currently in use include: •
Health and Safety Executive Safety Zone Infringement Report format
•
Emergency Rescue and Recovery Vessel Owners Association (ERRVA) ‘Warning Off’ Reports
The reporting and analysis system should be simple to use, be accepted as useful by personnel rather than a chore. It shall also provide feedback to organisations, management and front-line personnel and have demonstrated management support and be non-punitive. Hence on the latter point, published analyses should be anonymous. The regulatory agency’s approach to such a system is critical to its success but vessel and Installation operators must demonstrate similar commitment.
2.8 Reporting and Follow-up Most passing vessel collisions are reported comprehensively and should continue to be. Reporting of attendant vessel collisions is probably less complete, particularly when there is little or no damage. Similarly, there are doubts over the completeness of offtaker incident reports. In order to properly assess the probability of collision and to put effective controls in place, it is essential that as many incidents, near misses and other close quarters situation, are reported comprehensively and accurately. Various reporting formats are in use, some examples are given in Addendum 7. Responsibilities for reporting and following up any near misses which threaten their Installation(s), should be set out in Dutyholders’ collision avoidance procedures. When near misses involve attendant vessels and offtake tankers, then the Dutyholder’s own vessel selection and operating procedures should be reviewed. The Dutyholder should also review the incident with the vessel operator. In the case of passing vessel incidents, the Dutyholder should take the initiative, but regulatory agency’s (Health and Safety Executive, Department of Industry (DTI) and Maritime and Coastguard Agency (MCA)) assistance will be required to follow up with offenders. At the least Dutyholder’s concerns should be conveyed to the vessel and its operating management. In extreme cases and for Safety Zone infringements, prosecution may be possible, but a high standard of proof is required (refer to the Safety Zone Infringement Report (Addendum 7 for guidance). Whenever lessons are learnt as a result of investigation and follow-up, these should be shared with Installation and vessel personnel, owners, other operators and the industry generally. Periodically, Dutyholders should use available data to assess and update their collision avoidance procedures.
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2.9 Auditing All personnel from management through to workers on the Installation need to have confidence that the CRM system and collision avoidance procedures are effective. Hence, audits at appropriate intervals are essential to provide assurance that they are working as intended. Audits can be carried out by operator’s personnel familiar with but not involved in the operation. Alternatively, outside Auditors can be chosen for their specialist knowledge. In either case it is essential that the Auditor is sufficiently independent to take an objective view and that he/she reports directly to a senior level of management. Templates for system audits are given later in Addendum 3 . In broad terms those audits should review the following: •
Demonstrated management commitment to CRM including ‘sign-off’ at appropriate levels
•
Identification of the level of risk of vessel collisions
•
Mitigation and control measures, to reduce the probability to ALARP
•
Operating practices designed to minimise the frequency of collisions
•
Effective procedures to ensure the suitability of attendant vessels and the competence of their crews
•
Means of detecting and communicating with an approaching vessel and means of alerting the Installation personnel to the threat (refer to Addendum 2)
•
Appropriate facilities and procedures in place to evacuate and rescue Installation personnel
•
Contingency plans which address the risks to and rescue of vessel personnel
2.10 Performance Standards Dutyholders must set standards for collision avoidance and regularly measure performance against them. Data may include:
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•
Frequency at which all term chartered vessels are audited
•
Percentage of spot vessels inspected
•
Number of reported near misses
•
Number of ‘warning off’ calls by ERRVs
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Negative measures of performance, which should also be assessed, include: •
Number of collision incidents
•
Number of Safety Zone infringements
•
Number of stationkeeping incidents involving offtake tankers
Examples of performance standard formats include:
3
•
UKOOA Tandem Loading Guidelines, Background Report – Shuttle Tankers
•
UKOOA Tandem Loading Guidelines, Towing Assist Vessel (TAVs) Volume 2 Section 6
•
UKOOA Health and Safety Management Systems Interfacing
PASSING VESSELS 3.1 Introduction As mentioned above in Paragraph 2.3, incidence of passing vessel collisions in the UK sector is very low. To date no passing vessel collision on UKCS has resulted in the total loss of a vessel or an offshore Installation, although some have come close and catastrophic collisions involving passing vessels have been experienced worldwide. Passing vessel collisions are a MAH and must be addressed accordingly. The operator should have a system in place for managing these risks. Design loads which offshore Installations can absorb, are such that an Installation may not survive impact from anything of greater mass than a large fishing vessel or small coasting vessel at operating speed. But apart from choosing the location, the operator has little or no influence over the potential for passing vessel collisions (refer to Addendum 10). The primary causes of collision with offshore Installations include: •
Poor watchkeeping onboard the approaching vessel
•
Ignorance of the Installation’s presence due to it being new, due to poor visibility and/or poor radar watchkeeping
•
Setting a course too close to the Installation due to ignorance or irresponsibility
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Secondary causes or contributory factors may include: •
Vessel watchkeeper failing to detect the Installation due to inattention, distraction or simply not expecting a structure in that area
•
Vessel control failure at a critical point
•
Vessel drifting out of control
•
ERRV failing to detect an approaching vessel due to overload, distraction, poor visibility, obstructed radar or visual view
•
Unsuitability or inadequacy (refer to Addendum 2)
of
ERRV
equipment
or
manning
•
ERRV failure or inability to contact an approaching vessel because it is not keeping a proper visual or radio watch
•
Failure of approaching vessel to take avoiding action in sufficient time
Adverse weather can increase the probability of most of the above. A common theme is poor watchkeeping, particularly on the approaching vessel.
3.2 Assessing the Potential for Collision The probability of a passing vessel collision is most readily assessed at the design stage, when there is opportunity to influence the Installation’s location. This can be done using appropriate shipping traffic databases and vessel/Installation collision models. The traffic database contains analysis of traffic levels at the location. The collision model uses this, in part, to determine the likelihood of experiencing a collision (refer to Addendum 9). In critical areas site-specific radar surveys may be needed to establish accurate traffic patterns and levels. Local users such as ferry operators, regular shipping lines and fishing organisations can usefully be consulted at this stage. Assessment of traffic is a required part of the Application for Consent to Locate submitted to Ports Division of the Department of Transport, Local Government and the Regions (DTLR). This applies equally to fixed and mobile Installations. Factors which affect the probability of collision and which need to be assessed include:
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•
Traffic density close to the target location
•
Proximity to ferry routes, traffic separation schemes, deep water routes and/or constricted navigation channels
•
Other types of shipping passing nearby
•
Size, speed and peculiarities of passing traffic
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•
Fishing activity, both en route to fishing grounds and fishing in the area
•
Estimates of levels of competence among crews of regular traffic
Additionally, in busy areas, the authorities may require that potential modification to traffic routes and any resultant increase in probability of vessel/vessel collision be assessed. It is essential to identify regular traffic passing through the area and to consult with their representatives. These regular users should then be informed of subsequent developments. Although traffic density has a significant effect on the probability of collision, other relevant factors are listed below: •
In the approaches to a busy port or in busy channels, navigators will normally be on a high state of alert and once aware of the Installation will take avoiding action, albeit at close quarters. This makes good communications essential so as to identify those vessels which have or have not detected the Installation
•
Fixed Installations in low to medium traffic areas will become known and even used as navigation reference points. Hence, navigators will be aware of the Installation’s presence and take avoiding action. However, this can increase the probability of collision if the Installation is used as a way point and/or vessel navigation equipment is slightly inaccurate
•
The existence and location of mobile units in open waters must be promulgated widely, even if traffic density is low. There is a possibility of a vessel setting a course close to the location, without knowledge of the Installation’s presence. As a result navigators will not be expecting obstructions and may approach at a lower alert state, with only occasional radar and visual lookout
The primary concern is surface collisions with passing vessels. However, a few collisions between submerged submarines and structures have occurred. The Ports Division and Ministry of Defence (MoD) may require additional promulgation and fitting of submarine beacons in areas where submarine operate. Fishing vessels can foul their gear on underwater facilities in oil and gas fields. In extreme cases this hazards the lives of the fishing vessel crew and can damage the facilities. Good communications with representative fishing organisations and effective promulgation will improve awareness and may lower the frequency of fishing vessel incidents.
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3.3 Minimising the Probability of Collision 3.3.1
Design
During design, it may be possible to adjust the location, it may also be possible to take advantage of natural features such as shallow water for protection. In some cases DTLR may require adjustment. The requirements for detection of and communication with approaching vessel should be addressed at the design stage. Effective marking of the Installation’s presence is essential. Depending upon the level of risk, this may include enhanced lighting, high visibility paint, radar reflectors, radar responders and Automatic Identification of Ships (AIS) (refer to Addendum 2). 3.3.2
Promulgation (refer to Addendum 2)
The presence of an Installation must be promulgated to the marine industries, in advance of emplacement and continually once on location. Advance Promulgation
The following may be used as appropriate to local conditions: •
Consultation with and advice to identified generators of traffic such as ferry operators, regular shipping lines and local fishing organisations
•
Provisional notices to mariners via United Kingdom Hydrographic Office (UKHO)
•
Navigation warnings by radio and NAVTEX again via UKHO
•
Rig move warnings for mobile Installations
•
Kingfisher Information Services (KIS) fortnightly bulletins to the fishing industry and inputs to fish plotters
After Emplacement
Some or all of the following should be used depending upon local conditions and risk assessment:
20
•
Regular repeats of navigation warnings
•
Further notices to mariners
•
Marking on navigation charts, paper and electronic
•
Fish plotter databases, including FishSafe and similar systems designed to alert fishermen to underwater structures
•
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Dedicated guard vessels on location for short-term emplacements
•
‘All Ships Safety Call’ by Digital Selective Calling (DSC) from Installation or support vessel followed by ‘Securite’ messages on Very High Frequency (VHF) radio
•
AIS or Racon
Note:
If a mobile Installation is drilling an exploratory well in a congested or sensitive area, radar traffic surveys can be carried out from the unit or support vessel. The data collected will be useful in planning for any future developments.
3.4 Collision Avoidance Measures 3.4.1
Detection and Communications
Detection
Manned Installations should have a means of detecting approaching vessels which is appropriate to the traffic density, the probability of collision and potential consequences. The detection method will normally involve either Installation personnel or support vessel personnel. Addendum 2 offers guidance on possible levels of detection related to the type of Installation, the relative openness of the location and traffic density. Active detection of vessels approaching Normally Unattended Installations (NUIs) is impractical unless within the radar coverage of a field support vessel or radar system. The hazards which passing vessel collisions pose to such Installations are environmental and commercial. Any such collision also presents hazards to the vessel and to its crew. The Dutyholder must have a considered policy in place for when the NUI is manned which is based upon the probability of collision and the potential consequences and which ensures that risks to personnel are consistent with ALARP. Detection systems may include: •
ERRV radar and visual surveillance
•
Installation/field radar surveillance
•
Radar surveillance from shore or other facility
•
Installation visual lookout – probably limited to marine vessels acting as Installations
•
AIS combined with radar in high-density traffic areas
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Radar detection has the advantage that the approaching vessel’s movements can be plotted and accurately assessed. On the ERRV the radar and visual data is interpreted by skilled marine personnel. Such personnel may not be present on an Installation. Tracks of vessels relevant to the Installation can be determined by integrating radar data with an accurate positioning system such as Global Positioning System (GPS). The disadvantages of ERRV detection are that certain sectors may be masked by the Installation itself (refer to SBV Guidelines Section 3.6.3 on Radar Watch During Close Standby). If the ERRV covers more than one Installation, procedures and responsibility for radar surveillance of the approaches to all the Installations must be clearly understood on vessel and Installations. Installation mounted radar systems have the advantage of a wider horizon and a steady platform. Modern systems can transmit the data in real time to the SBV hence, removing the need for marine specialists on the Installation. Refer to Addendum 2 for discussion on appropriate detection systems. Note:
With the implementation of AIS, it will be possible to identify approaching vessels within VHF range, whether they can be seen visually or not; they could then be contacted by radio via Global Maritime Distress and Safety System (GMDSS) procedures. Vessels of 300 GRT and upwards should be equipped with AIS by 2006. Full implementation is due in 2008. Dutyholders for Installations in high-density/high-risk areas may consider installing such detection equipment as more and more vessels become equipped (refer to Addendum 2).
In all cases the operator should ensure that detection methods are appropriate to the probability of collision and potential consequences for the location and the time required for effective response. They should also ensure that surveillance data is interpreted by skilled marine personnel (also refer to SBV Guidelines Section 3.2 on Errant Vessels.) Communications
Whatever detection method is used, the operator of that system (normally the ERRV master) must have access to communications equipment and procedures which:
22
•
Enable him to contact an approaching vessel by radio via GMDSS procedures including use of VHF calling channels (see note above on AIS)
•
Have back-up communications equipment with which to attract the attention of an approaching vessel; these may include sirens, searchlights, signalling lamps, maroons and rockets
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•
Be able to communicate with the OIM and hence alert him of the approaching threat
•
Contact other vessels in the area to alert them to the threat and/or seek assistance
3.4.2
Manning and Equipment
Manning
Both the Installation and the vessel(s) with responsibility for detecting approaching vessels should be competently manned to carry out their duties. If detection and communication is the responsibility of a support vessel, then sufficient watchkeepers with appropriate, verified skills and competence should be provided. The Dutyholder must be satisfied of this, whether or not he is directly responsible for providing the vessel (refer to Offshore Support Vessel (OSV) Code Appendices 2 and 3). If detection, assessment and subsequent communication are the responsibility of Installation personnel, then the Installation should be manned accordingly with sufficient personnel, having the appropriate skills and knowledge, on duty continuously. Except in congested waters, the probability of collision is low. None the less responsibilities in such an event must be clearly understood by both Installation and support vessel personnel, regardless of the probability. Management must ensure that responsible personnel are constantly alert. Procedures and contingency plans should be exercised regularly to achieve this. Equipment
Dutyholders should ensure that specialist equipment appropriate to the probability of collision and potential consequences is provided and maintained correctly. This may include: •
Radar surveillance systems of appropriate range and definition
•
Radar beacons where indicated
•
Identification systems such as AIS
•
Communications systems, not only between Installations and attendant vessels but also for communicating with approaching vessels by VHF radio and in accordance with GMDSS procedures
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3.4.3
Assessing the Threat
In the case of a potential collision, the OIM will have to assess many things in a short time, considerations will include: •
Speed of approach and time to CPA/collision?
•
Time required by Installation to take action?
•
Is vessel following a normal route?
•
Is vessel apparently under power or drifting?
•
If drifting, is it under control?
•
Have communications been established with the vessel?
•
What other options are available for contact?
•
What is the size of the vessel and hence potential impact energy?
•
Are other marine traffic or Installations in the area likely to affect vessel’s course and actions?
•
Weather conditions, their potential effects on the vessel’s actions and on any evacuation?
•
Are there other vessels that may assist?
•
Where on the Installation is collision likely, is this a particularly vulnerable point?
•
At what point should the Installation consider shutting down vulnerable operations?
•
At what point should an evacuation commence?
Refer to SBV Guidelines in Addendum 4 and 5 of this document – Collision Avoidance Strategy flowchart and notes on contingency planning below. 3.4.4
Contingency Plans
Each Installation should have in place succinct procedures for action when a passing vessel poses a collision risk. Contingency planning should include:
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•
Responsibilities for detection, communication and assessment of the threat
•
Time to possible impact for alerting the Installation to the threat
•
Time to possible impact for initiating shutdown of plant and evacuation
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•
The decision points and actions for a controlled shutdown and evacuation in the case of drifting vessel threat
•
Actions of attendant vessel(s) in case of imminent threat
•
Estimating the point of impact for given wind and tide conditions and it’s effects on the evacuation plan
Refer to Paragraph 2.6. Note:
The plan needs to differentiate between actions required in case of a powered vessel threat, when time is likely to be extremely short and a drifting vessel when more time is available for considered action.
Actions of attendant vessels should not present hazards to the lives of crews, increase the probability of collision by modifying the behaviour of the approaching vessel or impair the attendant vessel’s ability to rescue personnel if the collision should occur. The Dutyholder should set parameters for implementing various levels of response appropriate to the location, Installation and local traffic patterns. The parameters for activating contingency plans may include: •
Vessel on a steady course with CPA < X.X NM expected to pass through Installation Safety Zone in XX minutes
•
Vessel due to pass through Safety Zone in XX minutes, has failed to communicate or failed to respond to attendant vessel communications
•
Vessel on apparent collision course due to impact Installation within XX minutes
Dutyholder should determine the values ( XX ) as part of the Safety Case risk assessment. Refer also to the EER assessment guidance in the SCRs (SI 1992/2885) and PFEER.
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3.4.5
Follow-up
Every incident or potential incident should be reported and followed up. Only by so doing can the potential for collision can be properly assessed (refer to Paragraph 2.8). In all cases, lessons and outcome should be fed back to the Installation and vessel personnel and to respective managements.
4
ATTENDANT VESSELS 4.1 Introduction Cargo operations account for the largest number of recorded infield vessel collisions in the UK sector, followed by standby vessels, anchor handlers, diving vessels, and a few survey vessel incidents. Collisions involving the last two groups were almost exclusively caused by mechanical failure. Collisions between construction/accommodation vessels and Installations are almost unknown but are none the less foreseeable. They would probably result from mooring/mechanical failure or stress of weather. These results are consistent with exposure. Supply vessels are required to work very close to Installations in marginal weather conditions as there is an increase in recorded incidents in late autumn and winter. EERVs although constantly in the vicinity of UK Installations, only make a close approach to cover overside working. Collision incidents increases during the summer maintenance season when more close standby is required. Although diving vessels set up very close to an Installation, they are less frequent visitors, have more sophisticated control systems and skilled Bridge Teams familiar with the risks. Among the more obvious and frequently reported causes of attendant vessel collisions are: •
Equipment failure
•
Personnel misjudgement
•
Weather (which includes environmental factors such as wind, tide, current and wave drift and may also be considered to be ‘misjudgement’)
The Health and Safety Executive Report on Effective Collision Risk Management (OTO 1999 052), breaks down reported causes by vessel and operation at time of impact and Section 6.3 of the report should be consulted for further details. In very broad terms it shows about 40% misjudgement, 30% equipment failure, 10% weather and 20% unspecified causes. Misjudgement is significant during close support work by supply vessels.
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4.2 Assessing the Potential for Collision The potential for attendant vessel collision is related to the working area, weather and tidal conditions, frequency of vessel visits and the operating culture in relation to marine activities. These should be examined in greater or lesser detail by means of risk assessment which includes marine expertise (ideally the vessel operators). The potential consequences to the Installation of a collision vary with the speed, size and type of vessel. The point of contact on the vessel is also a factor. Although this document does not address consequences of collision in detail following are some considerations: •
A small supply or standby vessel which experiences a slow sideways collision imparts low impact energy at the point of contact
•
A large supply vessel at near full speed colliding bow on would cause severe damage
•
Anchor handlers are very stiff in the region of the stern roller and can cause severe local damage even at relatively low speed
Among the underlying causes of attendant vessel collisions are: •
Failure to ensure adequate, competent and knowledgeable crew on both vessel and Installation
•
Lack of marine understanding by Installation personnel eg calling in a supply vessel in marginal conditions
•
Excessive numbers of Installation visits due to poor planning
•
Excessive time ‘standing by’ for the next lift or remaining connected to a bulk hose
•
Standby vessels ‘dodging’ too close to or upwind of the Installation
•
Steering directly for the Installation on approach
•
Poor relationships/communications between vessel and Installation which fails to promote good planning and early warning of developing problems
•
Not consulting the master or not trusting his judgement
•
Inadequate bridge manning and hence failure to anticipate a developing problem when the senior watchkeeper is distracted by other tasks
• •
Bridge personnel distracted by other tasks eg communications, paperwork Not adhering to procedures/guidelines
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•
Poorly sited or inadequate reach cranes
•
Weather side working in marginal conditions
•
Bulk hoses of the wrong length
•
Lack of appreciation, by vessel personnel, of the dynamics of working with floating Installations, particularly those free to rotate
•
Lack of understanding of thrusters/wash interaction when working with powered floating Installations
•
Selection of vessels unsuitable for the task
•
Multi role vessels with inadequate power or manoeuvrability
•
Vessel crew fatigue, often a consequence of inadequate work planning
Any of the above can be exacerbated by an unexpected equipment failure or worsening weather. As these causes are foreseeable, they should be planned against. At no time should the vessel master or officers be under any pressure or obligation, either direct or indirect, to commence or continue with operations where the safety of personnel, the vessel or the Installation is prejudiced. No operation should be undertaken without prior assessment of the risks. This may be a toolbox talk using checklists for routine operations or a more formal risk assessment for unusual or exceptional operations. In all cases key personnel who will be carrying out the task must be involved in the risk assessment (refer to OSV Code Section 9.6 Weather Side Working Risk Assessments).
4.3 Minimising the Probability of Collision 4.3.1
Vessel Suitability and Vetting
The Dutyholder must be satisfied that vessels visiting and/or working at their Installations are suitable for the task. It is the owner’s responsibility to provide a vessel which is fit-for-purpose, given an accurate scope of work. Support vessels must be capable of operating at the location, in the worst expected weather and tidal conditions, be suitable for the planned work and the peculiarities of the Installation. For example, a large modern supply vessel may be more suitable due to higher operating standards and power, despite greater potential impact energy. A small, underpowered and poorly manned vessel may be less suitable due to the greater potential for loss of control. Other considerations include:
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•
Strong tides
•
Heavy passing traffic
•
Excessive overhang
•
Freedom of the Installation to weathervane
•
Dynamic positioning and thruster interaction between vessel and Installation
•
Working alongside ship-shape Installations
•
Short crane reach
•
Cranes limited to one side
When Dutyholders do not directly charter support vessels, they must still satisfy themselves as to vessel suitability and capability. They should agree vetting procedures with the operator or service company responsible for providing the vessels. Refer to the Guidance for Health and Safety Management Systems Interfacing issued by Step Change in Safety. Term chartered vessels should be inspected on behalf of the management by a Marine Specialist, familiar with the workscope. Pool vessels should have at least an in-date UKOOA Common Marine Inspection Document (CMID), backed up by spot inspections. For spot chartered vessels, the Dutyholder must make a judgement on the necessity of a specific fitness-for-purpose inspection based on the vessel’s specification, plus the t he vessel vesse l and its it s owners reputation in the area. If in doubt the vessel should be inspected, its capability and the crew’s competence verified. In general vessels should operate in line with the UKOOA OSV Code and/or the Standby Vessel Operations and Survey Guidelines. Examples of industry standard codes and inspection/audit formats are given in the Addendum 4. The Dutyholder should also ensure that the vessel and its crew: •
Understand what is expected of it
•
Hold the field/Installation data card (OSV Code Appendix 8 and Appendix E)
•
Holds vessel operator procedures relevant to the particular operation
•
Hold and familiar with appropriate UKOOA guidelines mentioned above
•
Hold any field or operator-specific information
•
Aware of and in possession of any specific CRM procedures for the location
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4.3.2
Manning
All field vessels must be manned by marine crews adequate and competent for: •
The type of vessel
•
The type of operation
•
The locality and peculiarities of the Installation
•
The required working hours and rotation
Supply vessels are not normally manned for round the clock cargo operations, hence if such operations are likely, sufficient bridge and deck personnel must be carried to ensure adequate rest, including a night master or driving mate. Anchor handling vessels chartered for extended operations should be manned for round the clock working. Otherwise, vessel rest periods must be built into the programme. Similarly, standby vessels are not normally manned for extended round the clock close standby. If such support is anticipated, then manning should be adjusted. As part of the vessel vetting process, manning standards and procedures should be verified. These should include: •
Two-man bridge manning within an Installation Safety Zone (supply and standby vessels)
•
Engine room manning at critical periods, including safety zones
•
Adequate deck crew for cargo operations
•
Adequate crew for anchor handling, including round the clock working if required
•
In heavy traffic areas, consider need for additional bridge watchkeepers specifically for detection and communications duties
•
In general, sufficient manning for adequate crew rest and avoidance of fatigue
Refer to OSV Code Appendices 1 and 2 on Manning and Training and the International Marine Contractors Association (IMCA) CMID.
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4.4 Collision Avoidance Measures 4.4.1
Support Vessel Operations
Masters and Installation personnel must be prepared for potential problems whilst vessel is in close proximity and must make adequate contingency plans. These plans should be exercised at regular intervals, when safe to do so, particularly in relation to potential control/mechanical/propulsion failures. During field operations the master and Installation personnel should continually review prevailing conditions and actual operation as an ongoing risk assessment, factors to be reviewed include: •
Environmental conditions, for example tidal conditions, changes in wind direction and strength and seastate
•
Changes in workscope, for example extended duration and commencement of hose work
•
Human factors, for example likely duration of task, fatigue and rest periods
In general refer to the guidelines Task-based Risk Assessment produced by Step Change in Safety. It is the master’s prerogative to modify or suspend any operation which involves unacceptable hazards to personnel, the vessel or the Installation. He should discuss this with Installation personnel unless the urgency of the situation demands immediate action. The master should question any instructions received, which potentially hazard personnel, the vessel or the Installation. The work programme and/or field rotation should be planned so as to minimise Installation visits. Vessel movements within the field should be based on the precautions below plus any others appropriate to the particular trade, operation or location: •
Steer offset courses to or from Installations during passage
•
Establish suitability of current environmental conditions and trends for the work programme at the particular location
•
Anticipate the effects of future weather and currents
•
Avoid passing close up wind or tide when on passage or when ‘dodging’ on low power
•
Two competent persons on the bridge whilst approaching and in the Safety Zone
•
Complete Safety Zone pre-entry checklists as per requirements of the data card
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•
Obtain permission from the Installation before entering the Safety Zone
•
Before approach, confirm readiness to work a supply vessel in the most expeditious manner, in a safe location and with minimum time alongside
•
Approach the Installation at a safe speed and heading
•
Before final approach, set-up the vessel minimum 50m from the proposed working location in order to assess the actual environmental conditions, motion and behaviour of the vessel
•
Be aware of different handling characteristics between ‘light’ and loaded conditions
•
Do not retain vessel alongside the Installation for extended periods of ‘standby’ when not employed
•
Do not retain vessel with hoses connected for extended periods when not transferring cargo
•
Be aware of the limited capability of some multirole vessels
•
Move outside the Safety Zone when not required in close proximity to the Installation
Further guidance is given in: •
OSV Code Section 7.5.2 on checks before entering Safety Zone
•
OSV Code Section 8 on CRM for infield vessels
•
OSV Code Section 9 for general guidance on Installation vessel operations and 9.6 for weather side working practices
•
OSV Code Appendix 11 for pre-entry checklists
•
SBV Guidelines Section 2 on approaching the Installation
4.4.2
Installation/Vessel Communications
Good communications between vessels and Installations are essential to ensure understanding of priorities and to assist in the Identification of hazards. These should include:
32
•
Dedicated clear radio channels or other means of communication
•
An established, accessible point of contact on the Installation whenever the vessel is working in close proximity
•
Review of proposed work programmes between Installation and vessel, taking account of the master’s specialist expertise
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•
A procedure for working conditions
constant
review
•
Agreed emergency communications which includes a safe escape route
of
plan
weather
and
conditions
contingency
and
plan,
Also refer to OSV Code Section 9.2. 4.4.3
Special Precautions – Weather Vaning and DP Installations
Floating production storage and offtake units and drill ships involve particular marine hazards different from fixed platforms, jack-ups and anchored semisubmersibles. The peculiarities below may increase the potential for collision with attendant vessels. 1.
With the exception of a few semi-submersible production units, they tend to be ship shaped.
2.
Most are moored to a single point and to some extent free to rotate and align with wind/current/tide.
3.
Some are controlled by thrusters and partially or wholly maintain position and heading by (thrusters can interact with those of a vessel working alongside).
4.
They may have limited reach carnage.
5.
Supply vessels may have problems adopting a weather kindly heading when working cargo with these Installations.
Generally, such Installations are straight sided, their motion is unpredictable and may involve unexpected thrusters wash. Precautions for support vessels working in close proximity to such Installations precautions include: •
Prior to setting up, vessel and Installation personnel should discuss and understand the particular hazards of the operation
•
Appreciation by vessel personnel that a weather vaning Installation may move unpredictably
•
Understanding of thruster interaction between the Installation and vessel
•
Appreciation by Installation personnel that they must keep vessel advised of any actions which could increase the potential for collision
•
Contingency plans, including a safe escape route for the vessel, in the event of a rapid change in the situation
Also refer to OSV Code Appendix 14.
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4.5 Contingency Plans Each Installation should have in place a succinct contingency plan for immediate actions in case of an attendant vessel collision. These actions may include, according to location, Installation and the type of operation: •
Rapid evacuation of the Installation personnel, if required
•
Rescue of the attendant vessel crew
•
Dealing with a ruptured riser or pipeline
•
Fire and/or explosion
•
Location of sensitive seabed facilities in the vicinity of the Installation
•
Shutting down production and/or pipelines
Refer to the Evacuation, Escape and Rescue Assessment guidance in the Safety Case Regulations (SI 1992/2885). Also refer to Paragraph 2.6 of this guide.
4.6 Follow-up Every incident or potential incident should be reported and followed up. Only by so doing can the potential for collision be properly assessed (refer to Paragraph 2.8). In all cases, lessons and outcome should be fed back to Installation and vessel personnel and managements.
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5
OFFTAKE TANKERS 5.1 Introduction In a few cases, offtake tankers load from fixed platforms but are more are often associated with FPSO/Floating Storage Units (FSUs), transhipping and transporting the produced crude oil to shore terminals. Transhipment may take place via a separate loading buoy or directly from the FPSO/FSU. Having two large vessels loaded with hazardous cargo in close proximity for extended periods introduces obvious hazards. Any collision, even at low speed may cause significant damage with major consequences to life, the environment and the business of the operator. Precautions and controls are given in detail in the UKOOA Tandem Loading Guidelines. Further expert guidance is given in the Oil Companies International Marine Form (OCIMF) Offshore Safety Loading Guidelines.
5.2 Assessing the Potential for Collision Factors associated with offtake tanker operations which can affect the probability of collision include: •
Frequency and duration of offtakes
•
Whether hawser connected
•
If DP, the DP class
•
Whether offtakers are dedicated to the particular operation
•
Relative congestion of the field
•
Whether either or both vessels are thrusters controlled or free to rotate
•
Whether support vessels are used for mooring and towing assistance either for alignment or maintaining tension
Experience shows that underlying factors may include: •
Reliability of position referencing systems for DP tankers – the possibility of references dropping out must be allowed for in risk assessment
•
Standards of propulsion/control system redundancy in non-dedicated offtake tankers and the potential for power failure and position loss
•
Use of heavy fuel in some non-DP tankers again with potential for power failure
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Ship/Installation Collision Avoidance
•
Changeover from automatic to manual controls (some propulsion systems are known to fail at full pitch and the time to regain control before significant momentum is gained) is critical
•
Differences between tanker trade and offshore DP practice; this may affect bridge and engine room manning practices and DP tanker bridge management – for example a tanker master normally retains control, whereas in diving vessels dedicated DP operators man the consol; engine room controls must be manned during offtake to allow for immediate response to problems
•
Training and familiarisation of tanker crews – again a function of the different cultures
•
Fish-tailing and surging – the tendency of FPSO/FSUs to move in a seaway in a manner difficult to follow accurately with manual or DP control of the offtaker; excessive movement can result in mooring failure or collision
•
Thruster failure modes – as above some are known to fail at full pitch
•
Main propulsion failure – if continuous running is required to maintain mooring tension, propulsion failure may result in collision with the storage vessel or buoy
•
Pressure to continue production or transhipment – may persuade masters to moor and remain moored in marginal conditions so as to maintain production or offtake
These factors, the capability of the offtaker together with the operating standards and procedures should be the subject of risk assessment for each combination of field and offtaker.
5.3 Minimising the Probability of Collision Specific guidance on two-vessel offtake operations is given in IMCA document M161 Design and Operation of DP Vessels – Two-vessel Operations. The Dutyholder’s management must ensure:
36
•
That only suitable vessels are chartered
•
That vessel suitability is verified by persons with the necessary experience and knowledge
•
That operating methods and procedures both for the tanker and the offtake operation are appropriate to the identified hazards of that particular location
•
That the system is audited at appropriate intervals
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The various responsibilities should be set out in the JOPs as should the means of implementing them. 5.3.1
Offtake Tanker Suitability:
Overall the vessel equipment and manning should be confirmed as suitable for and capable of carrying out the transhipment operation in the worst conditions anticipated. Detailed guidance has been developed by OCIMF, Intertanko, IMCA and the UKOOA FPSO Committee. This guidance is listed in Addendum 7 of this document. 5.3.2
Equipment
Offtake tankers equipment should meet the following criteria: •
Propulsion, control and DP systems, where fitted, should be adequate, to moor, remain on location and unmoor safely in the most severe operating environmental conditions anticipated, with adequate reserve power and sufficient redundancy
•
DP offtake tankers should meet Equipment Class 2 of International Maritime Organisation (IMO) Circular 645; in addition no known single failure mode should cause an emergency disconnect or cause a position excursion which necessitates emergency release of the loading hose and/or mooring hawser, if used
•
Mooring systems and equipment, if used, should be adequate, with sufficient reserves in terms of numbers and strength, to moor up expeditiously and remain on station in the worst anticipated operating conditions
•
Where thrusters are required to run continuously to maintain mooring tension or maintain station, sufficient redundancy of generation, propulsion, control and fuel systems should be available
•
Thrusters should normally fail to zero pitch or at last order; where thrusters fail to full pitch, then procedures for promptly regaining control should be in force
•
Position reference systems should include sufficient redundancy and diversity that loss or corruption of one system will not cause a loss of position; where DP computers use a reference voting system, no two systems should fail or be corrupted by the same fault or error; systems for identifying failures and regaining control should be sufficiently robust
The offtake tanker should undergo an annual DP trial in the IMCA format or similar.
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Ship/Installation Collision Avoidance
5.3.3
Manning
Provision of adequate and competent crew is critical to safe offtake operations: •
Manning should be adequate to provide sufficient alert, skilled personnel for all critical tasks on the bridge, in engine room and on deck for the duration of the offtake operation, including arrival and departure from the field
•
Manning practices should be appropriate to the hazards involved in loss of position; this should include at the least double manning of the bridge (the master should not be one of the DP operators) and continuous manning of the engine control room
•
Key personnel should be properly qualified, have experience of the vessel and offshore transhipment operations and at least have knowledge of the particular operation or one that is similar
•
Any changes of personnel should include adequate handover, overlap and replacement by personnel of similar knowledge and experience
Detailed guidance on personnel competence is given in UKOOA Tandem Loading Guidelines Volume 1 Appendix C – Key Personnel Competency Matrices. 5.3.4
Vetting
The suitability of the offtake vessel should be demonstrated using an industry standard format or system. Examples of such systems are given in Addendum 4. The vetting process is critical when chartering non-dedicated vessels, spot vessels or ones which are unfamiliar in the particular trade. Despite possible time pressures, allowance must be made for the vetting process. 5.3.5
FMEA
Tankers used for offshore offtake should be subjected to a systematic Failure Mode and Effect Analysis (FMEA) carried out by a specialist contractor. The report should be available to vessel personnel and made available to potential charterers/field operators. Any deficiencies noted should be allowed for in operating practices and procedures involving the vessel. If any significant changes are made to generating, propulsion or control systems, the FMEA should be repeated. Inspectors vetting a vessel should confirm that the FMEA report is current. Annual DP trials confirm performance against the FMEA.
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5.4 Collision Avoidance Measures 5.4.1
Operating Procedures
Succinct field-specific operating procedures should be produced and made available to offtake tankers. Field/vessel-specific JOPs should be developed. These procedures should cover as necessary: •
Operating parameters and constraints
•
Controlling environmental conditions and decision points
•
Communications provisions
•
Step-by-step arrival and departure procedures
•
Propulsion, control and stationkeeping requirements and methodology including towage assistance where used
•
Differences where appropriate between: fixed point (buoy) and tandem mooring; between DP and non-DP offtakers
•
Managing thruster interaction
•
Abort decision points: mooring, transhipping and unmooring
•
Emergency shutdown, disconnect and departure parameters and procedures
•
Safe vessel escape routes
The procedures should be supported by relevant checklists at required points in the operation. Some examples are given in Addendum 5. Where field operations require use of a TAV, this should be covered in the procedures. Refer to UKOOA Tandem Loading Guidelines Volume 2. 5.4.2
Contingency Planning
Each field in which offtake operations take place should have a standard contingency plan which can be adapted to individual offtakers in consultation with the master. Contingency plans for regular offtakers should be included in the JOPs. At the least, standard and specific plans should address: •
Significant offtaker propulsion or control problem during approach
•
Loss of position control at any time during the operation
•
Offtaker adrift, out of control, in the field
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Ship/Installation Collision Avoidance
•
Loss of or high mooring tension (hawser connected operations)
•
Collision or close quarters event between offtaker and FPSO
•
Abort parameters
•
Significant offtaker propulsion or control problem during departure
•
Fire and/or explosion
•
Support vessel casualty
Offtaker specific plans on both units should be confirmed by arrival checklists. Elements of the plan should be exercised periodically with dedicated offtakers. Refer to general remarks in Paragraph 2.6. 5.4.3
Reporting and Follow-up
It is only by accurate reporting of all incidents, near misses and close quarters events that the industries and individual operators can properly assess the level of risk. When collated and analysed these reports will aid implementation of further risk reduction and control measures, where they are needed. Field operators should implement procedures for recording all incidents and near misses. Suitable reporting forms and systems have been developed by IMCA and UKOOA FPSO Committee. Examples are referenced in the Addenda. Whenever a loss Dutyholder should:
40
of
position
or
more
serious
incident
occurs
the
•
Carry out an investigation, in cooperation with the vessel operator and regulatory agency where appropriate
•
Implement any lessons learned
•
Repeat the risk assessment and feedback the results to involved vessels, vessel operators and field personnel
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Addendum 1 Glossary of Terms The following terms when used in this document have the meaning as given below. Attendant Vessel
A vessel with legitimate business, supporting or working at the Installation, one with permission to enter the Installation Safety Zone.
Close Quarters Situation
One where a vessel is in such close proximity to another vessel or fixed object that the navigator has to take urgent avoiding action or where there is imminent potential for collision
Damage Criteria (Installation)
Catastrophic:
Damage resulting in shutdown of the Installation, including major structural damage and/or loss of stability, possibly resulting in evacuation and/or loss of life.
Severe:
Damage affecting the integrity of the Installation sufficient as to require repair in the immediate or short term (up to one month).
Moderate:
Damage requiring repair in the medium (up to 6 months) or longer (over 6 months) term.
Minor :
Damage not affecting the integrity of the Installation.
Dutyholder
The Dutyholder is the person who has the legal responsibility for the Safety Case and for implementing the health and safety responsibilities associated with it. In the case of a fixed Installation, it is normally the operator. For a mobile Installation, it is normally the owner/manager. The Dutyholder is defined in the Management and Administration Regulations (MARs).
Errant Vessel
A vessel which has failed to take avoiding action on approaching a fixed or moored Installation or has failed to respond to communications from the Installation or its attendant vessel(s); a vessel which poses or appears to pose a threat of collision with the Installation or its attendant vessels.
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Ship/Installation Collision Avoidance
Incident
Collision or unintentional contact between vessel and Installation.
Installation
An offshore unit engaged in exploration for or exploitation of hydrocarbons resources. May include fixed platforms, mobile drilling units (floating or self-elevating), floating production or Floating Production Storage and Offtake (FPSO) units.
Major Accident Hazard (MAH)
Near Miss
A hazard with the potential for serious personal injury resulting from: fire/explosion or the release of a dangerous substance; major damage to the structure or loss of stability; other hazard with the potential for five or more casualties. A Major Accident Hazard (MAH) is defined in the Safety Case Regulations (SCRs). The principle hazards are summarised in the ‘Purpose and Scope’ of this document. Circumstances which could have escalated into an incident and/or circumstances which require activation of emergency response procedures on the Installation. For attendant vessels a near miss may include: •
A loss of position control which if uncorrected could have resulted in a collision
•
An offtake tanker incident with the potential to cause a collision
•
Activation of emergency procedures related to collision risk on the Installation
•
Location-specific near miss parameters developed by Dutyholders
For passing vessels:
Glossary Add 1-2
•
A Safety Zone infringement is a vessel passing within 500m of the Installation
•
Failure of an approaching vessel, with Closet Point Approach (CPA) <500m to respond to calls from the Emergency Rescue and Recovery Vessel (ERRV) or Installation
•
Activation of emergency procedures Installation such as a precautionary muster
on
the
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Ship/Installation Collision Avoidance
Offtake Tanker (or Offtaker)
A tanker used for exporting produced oil from offshore fields via loading buoys, subsea connections or direct from storage vessels. Normally specially modified and equipped.
Passing Vessel
A vessel on passage to somewhere else, one that should keep clear of the Installation Safety Zone.
Safety Zone
The 500m radius exclusion zone established around all active surface Installations and some subsea Installations in the UK sector. In the case of floating storage units, it may be extended to include the swinging area of vessel and any tandem moored offtaker.
Support Vessel
An attendant vessel with specific duties at the Installation such as supply, towage, standby, diving etc.
Traffic Density
The following values give a comparison of densities in the UK Sector: Low Low to Medium Medium to High High
<1,000 passing vessels per year 1,000 to 5,000 vessels per year 5,000 to 20,000 vessels per year >20,000 vessels per year
The degree of concentration of traffic into narrow channels should also be taken into account when comparing the densities.
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Ship/Installation Collision Avoidance
Addendum 2 Promulgation and Detection – Passing Vessels Location Type
1.
2.
Fixed platform, open location
Mobile Installation, open location
Traffic Density
Light
Promulgation
•
•
Light
4.
NUI
Fixed platform near busy traffic route
Moderate
•
Clear surveillance and reporting responsibilities
•
•
Maintain alertness by regular exercises
•
Advance notices
•
ERRV radar
•
Installation radar if available and manned
•
Clear surveillance and reporting responsibilities
•
Maintain alertness by regular exercises
Standard markings
•
Advance notices to mariners
•
ERRV radar when manned
•
Marking on charts
•
Coverage from nearby Installation if available
•
Standard markings
•
Consider racon
•
Advance notices to mariners
•
Marking on charts
•
•
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•
Standard markings
warnings before and during time on location
Moderate
ERRV radar
Marking on charts
• Navigation
Standard markings
Additional Precautions
•
•
•
3.
Advance notices to mariners
Detection
Obscured sectors covered during close standby Clearly understood joint coverage arrangements
•
Obscured sectors covered during close standby
•
Clearly understood arrangements for any joint coverage
•
Clearly understood arrangements for any joint coverage
•
Responsibilities clearly understood
•
Radar surveillance from platform transmitted to ERRV
•
Clearly understood arrangements for any joint coverage
•
AIS detection
•
Responsibilities clearly understood
•
Consider extra bridge watchkeepers
•
Risk assess any multirole coverage
Consider racon
Promulgation and Detection – Passing Vessels Add 2-1
Ship/Installation Collision Avoidance
5.
6.
7.
Location Type
Traffic Density
Mobile Installation near busy traffic route.
Moderate
Mobile Installation in busy traffic area or near traffic node
Promulgation
•
warnings before and during time on location
Moderate to heavy
•
Standard markings
•
Consider racon
•
Advance notices
Radar surveillance from Installation transmitted to ERRV
•
Clearly understood arrangements for any joint coverage
•
AIS detection
•
Responsibilities clearly understood
•
Consider extra bridge watchkeepers
•
Risk assess any multirole coverage
•
Dedicated ERRV coverage
•
Responsibilities clearly understood
•
Clearly understood responsibilities and hierarchy on nearby Installation/ ERRV
•
• Navigation
warnings before and during time on location
Radar surveillance from Installation transmitted to ERRV
•
AIS detection
•
Extra bridge watchkeepers
•
‘Securite’ messages from ERRV
•
Standard markings
•
Consider racon
•
Advance notices to mariners
•
As the previous point when manned
•
Marking on charts
•
•
Standard markings; racon
Dedicated coverage from nearby Installation or ERRV preferred
•
Consider extra bridge watchkeepers
•
Any special precautions per consent to locate
Additional Precautions
•
• Navigation
NUI in Moderate busy traffic to heavy area or near traffic node
Note:
Advance notices
Detection
Any detection systems required by the above should be properly maintained hence reflecting their importance.
Promulgation and Detection – Passing Vessels Add 2-2
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Ship/Installation Collision Avoidance
Addendum 3 Systems Audits The Dutyholder should routinely and regularly audit the collision avoidance system. Auditors, either internal or external should have sufficient independence to objectively review working of the systems. They should report directly to the appropriate level of management. The formats which follow are intended as templates for auditing arrangements at individual Installations and fields. They are not definitive and should be adapted to local requirements.
1
SYSTEM MANAGEMENT (ALL SITUATIONS) Installation/Field
No
Dutyholder
Activity
Audit/Review Period
Responsible Person
Comments
1.
Manager responsible for collision avoidance assurance nominated?
2.
Internal/external Auditor nominated?
Auditor should not be part of the Installation operations department.
3.
Does Auditor report directly to nominated Manager on effectiveness of collision avoidance system?
Auditor should have direct access to appropriate management level without filtering by operations management.
4.
Has an agreed Policy Statement been developed and issued to Line and Installation Managers?
Should be endorsed by senior management.
5.
Do Line and Installation Managers understand the purpose and principles of collision avoidance?
Auditor should take samples of level of understanding.
6.
Are there sufficient personnel within the organisation with the necessary marine competence?
7.
Are vessel operators and mobile unit operators fully integrated into the system? Do they understand the principles of collision avoidance?
Review with vessel operators and crew.
8.
Are evacuation and rescue arrangements adequate and appropriate to the risks?
Check contingency arrangements in event lifeboats lost/damaged.
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Ship/Installation Collision Avoidance
Installation/Field
No
Dutyholder
Activity
Responsible Person
9.
Have joint arrangements (eg for shared ERRV coverage or when Dutyholder does not arrange support vessels) been agreed? Are they understood by line/Installation managers?
10.
Is there a robust system for vessel/Installation personnel to feed concerns to the management?
11.
Is there an effective system for reporting collision incidents and near misses?
12.
Do Installation and vessel personnel understand the importance of reporting near misses?
13.
Are incidents and near misses analysed, trends actioned and lessons fed back to operating personnel and vessel personnel?
2
Audit/Review Period
Comments
Who arranges and charters ERRVs?
PASSING VESSEL PROCEDURES (ALL SITUATIONS) Installation/Field
No
Dutyholder
Activity
Audit/Review Period
Responsible Person
Comments
1.
Are reporting lines to responsible Manager clear?
3.
Has the probability of a passing vessel collision been assessed?
4.
Are the means of detecting and communicating with an approaching vessel appropriate to the risk at the particular location? Are they maintained properly?
Refer to Addendum 2.
5.
Are the means of promulgating the Installation’s presence adequate and appropriate to the probability of collision and potential consequences at the location?
Refer to Addendum 2.
6.
Do OIMs, Installation and vessel personnel understand the risks and the purpose of the collision
Auditor should take samples of level of understanding.
Systems Audits Add 3-2
There should be clear lines from the Manager responsible for implementing passing vessel arrangements.
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Ship/Installation Collision Avoidance
Installation/Field
No
Dutyholder
Activity
Audit/Review Period
Responsible Person
Comments
avoidance system?
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Systems Audits Add 3-3
Ship/Installation Collision Avoidance
Installation/Field
No
Dutyholder
Activity
Audit/Review Period
Responsible Person
Comments
7.
Are there location-specific collision avoidance procedures?
8.
Do the procedures address situations when sectors are obscured during close standby and when a single ERRV covers more than one Installation?
Are the responsibilities clearly understood?
9.
Are the procedures reviewed with the ERRV/guard vessel and other support vessels during routine visits?
Ensure that vessel personnel understand their responsibilities.
10.
Who will review the procedures during these visits? How does he/she report any concerns to management?
Include regular and spot /relief vessels.
11.
Do support vessels understand the importance of passing vessel surveillance?
12.
Who charters ERRV/guard vessel?
13.
When the Dutyholder does not charter ERRVs and other support vessels, how does he ensure suitability for surveillance?
14.
Is there a robust system for vessel/Installation personnel to feed concerns to the management?
15.
Are contingency plans developed for responding rapidly to the threat of collision? Are they exercised regularly?
Systems Audits Add 3-4
Each Installation crew and each vessel crew should be exercised twice per year.
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Ship/Installation Collision Avoidance
3
ATTENDANT VESSEL ARRANGEMENTS (ALL SITUATIONS) Installation/Field
No
Dutyholder
Activity
Audit/Review Period
Responsible Person
Comments
1.
Are reporting lines to responsible Manager clear?
There should be clear lines of reporting and responsibility.
2.
Is there a robust system for ensuring the suitability of support vessels for the Installation/location and the adequacy and competency of the crews?
What are performance standards for inspections?
3.
Who is responsible for ensuring suitability of vessels and competence of crews? How does he/she report to management?
4.
How are vessels confirmed suitable before employment? •
Term chartered vessels
•
Pool vessels
•
Relief vessels
Check inspection performance standards.
• Spot vessels
5.
Who charters support vessels? Do they understand the importance of vessel suitability in collision avoidance terms?
6.
When the Dutyholder does not charter ERRVs and other support vessels, how does he ensure suitability?
7.
Do all support vessels hold field/ Installation data cards?
8.
Are there location-specific collision avoidance procedures?
9.
Are the procedures reviewed with the all support vessels during routine visits?
10.
Who will review the procedures during these visits? How does he/she report any concerns to management?
11.
Do OIMs, Installation and vessel personnel understand the risks of vessel platform collision and the importance of good communications?
Discuss with personnel.
12.
Do all support vessels complete a pre-entry checklist before approaching Installation? How is this recorded?
Check records.
Issue 1 February 2003
Identify person responsible for issuance.
Systems Audits Add 3-5
Ship/Installation Collision Avoidance
Installation/Field
No
Dutyholder
Activity
Audit/Review Period
Responsible Person
Comments
13.
Do Installation personnel dealing with support vessels have sufficient marine understanding for the task?
Check qualifications and experience.
14.
Do Installation personnel recognise that frequent visits and weather side working increase collision risks?
Discuss with personnel.
15.
Are support vessels released promptly on completion of task and not kept standing by unnecessarily?
Check procedures and actual activity.
16.
Do ERRVs and other vessels ‘dodge’ in safe areas in relation to wind and current?
17.
Have contingency plans been developed to respond to serious incidents? Are they exercised regularly ?
18.
Do contingency plans address rescue of vessel personnel?
4
OFFTAKE TANKER ARRANGEMENTS (FIELD SPECIFIC) Installation/Field
No
Dutyholder
Activity
Audit/Review Period
Responsible Person
Comments
1.
Are reporting lines to responsible Manager clear?
There should be clear of responsibility and reporting.
2.
Person responsible for auditing the system nominated?
Auditor should report to senior management.
3.
Is there a robust system for ensuring the suitability of offtake tankers for the location and the adequacy and competency of the crews?
Procedures and performance standards for vetting.
4.
Who is responsible for ensuring suitability of vessels and competence of crews? How does he/she report to management?
Systems Audits Add 3-6
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Ship/Installation Collision Avoidance
Installation/Field
No
5.
Dutyholder
Activity
Audit/Review Period
Responsible Person
Comments
What system/format is used for ensuring suitability before employment: Offtake tankers Crews
6.
Who charters offtake tankers? Do they understand the importance of vessel suitability and crew competence?
What is the relationship with the Dutyholder?
7.
How is the suitability of spot or relief offtakers verified?
8.
Are Joint Operations Procedures (JOPs) in use for each specified offtaker?
9.
Are the JOPs developed/ reviewed with vessel operators and personnel?
10.
Are other support vessels eg TAVs used? How is their suitability and crew competence verified?
11.
Have contingency plans been developed for emergencies? Are personnel familiar with them? Are the plans exercised regularly?
12.
Do OIMs and personnel and support vessel crews understand the potential for offtake collisions and the importance of good communications?
13.
Do all offtakers complete a pre-entry checklist before approaching Installation? How is this recorded?
Check records.
14.
Do Installation personnel dealing with offtakers have sufficient marine understanding for the task?
Check experience.
15.
Do procedures recognise the operating differences between DP and non-DP offtakers?
16.
Are the procedures for monitoring and controlling hawser tension in non-DP oftakes satisfactory?
17.
Is the manning of the bridge consol and engine rooms during DP operations adequate and satisfactory?
18.
Is there a robust system for vessel/Installation personnel to feed concerns to the management?
20.
Do Installation and vessel personnel understand the importance of reporting near misses? What reporting system/format is used?
21.
Are incident and near misses lessons discussed with and fed back to Installation and vessel personnel?
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Systems Audits Add 3-7
Ship/Installation Collision Avoidance
Systems Audits Add 3-8
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Ship/Installation Collision Avoidance
Addendum 4 Vessel Suitability and Inspection Formats
1
COMMON MARINE INSPECTION DOCUMENT – UKOOA Standard document for assessing offshore support vessels, developed by UKOOA in association with other stakeholders. Valid for up to one year unless significant changes occur in the interim. It includes general sections common to all offshore support vessels plus type-specific appendices. The format can be obtained from UKOOA or IMCA (refer to Addendum 11).
2
FITNESS-FOR-PURPOSE INSPECTION When a vessel is chartered for a specific project or task then a fitness-for-purpose inspection is recommended. This should cover at least:
3
•
The specific task or project
•
Currency of standard inspections such as CMID, the IMCA DP annual inspection, FMEA etc as appropriate
•
Adequacy and redundancy of the vessel propulsion and control systems for the project in anticipated operating conditions
•
Adequacy of specialised equipment for the project
•
Adequacy and competency of vessel personnel for the project
•
Certification status, particularly for lifting gear
IMCA DP ANNUAL INSPECTION This involves a comprehensive set of trials, carried out annually by specialists to confirm the operability of dynamically positioned vessels. It is recommended for all DP vessels from survey vessels through to the highest rated diving/construction vessels and offtake tankers. It confirms currency of the FMEA report. The M139 format is available from IMCA, refer to Addendum 11 for contacts.
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Vessel Suitability and Inspection Formats Add 4-1
Ship/Installation Collision Avoidance
4
SHIP INSPECTION REPORT PROGRAMME (SIRE) This is a comprehensive inspection document for various classes of tankers including bulk oil, chemical and gas carriers. Recommended for initial fitness for purpose assessment of offtake tankers, combined with the annual DP inspection where relevant. The SIRE document is published by Witherby and Co on behalf of OCIMF (refer to Addendum 11 for contacts).
Vessel Suitability and Inspection Formats Add 4-2
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Ship/Installation Collision Avoidance
Addendum 5 Field Checklist
1
PRE-FIELD ENTRY (OSV CODE APPENDIX 11) 1.1 Vessel 1.
Weather conditions are suitable.
2.
All required propulsion, control and back-up systems are operational.
3.
Master and crew are sufficiently rested.
4.
Deck crew are briefed and correctly dressed.
5.
Vessel’s programme has been advised/agreed.
6.
Communications with the Installation are working.
7.
Internal communications on vessel are working.
8.
Bulk transfer procedures have been agreed.
9.
Full details of cargo discussed/agreed.
10. Notification has been given and received of any expected helicopter movements.
1.2 Installation 1.
The required working zone alongside is clear of other vessels.
2.
All non-essential overside discharges in the working zone have been stopped.
3.
Standby vessel has been briefed on the operation.
4.
Installation personnel are sufficiently rested.
5.
Deck crew and crane driver are briefed.
6.
Weather limitations have been considered.
7.
Vessel’s programme has been advised/agreed.
8.
Crane limitations have been advised to Master.
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9.
Permission given to offload during diving operations.
10. Bulk transfer procedures have been agreed. 11 Full details of cargo discussed/agreed. 12. Underwater/waterline obstructions which could cause a hazard to the vessel notified.
2
OSV/FPSO CHECKLIST (OSV CODE APPENDIX 14) 2.1 Introduction This checklist details checks and exchange of information to be carried out by the master of the support vessel and the OIM (or his representative) of the FPSO. The list is in addition to any other checklists completed prior to entry into the Safety Zone.
2.2 FPSO Supplementary Checklist No
Check
1.
Risk assessment of all operations is to be carried out prior to operations commencing. To be completed by the Vessel Master, OIM and Crane Operator.
2.
FPSO to confirm its heading and that the heading will not alter or be altered during supply vessel operations.
3.
OIM to confirm motion of the FPSO in current conditions eg: •
FPSO roll (degrees)
•
FPSO roll (period)
•
FPSO pitch (degrees)
•
FPSO heave (metres)
Completed Yes/No
4.
A general exchange of information regarding the disposal of cargo to be offloaded to the FPSO and back loaded cargo to be received by the OSV.
5.
A general exchange of information regarding ‘hose work’ to be conducted. This will include the method of lowering the hose to the OSV and available space for this to be carried out safely. Where practicable sufficient deckspace must be available or be cleared so that the OSV crew have a safe area in which to handle the hose.
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6.
Confirmation from the OSV Master to any particular limitations on crane operations or special conditions affecting normal operation of the crane.
7.
Information from the OIM as to any particular limitations on crane operations or special conditions affecting normal operation of the crane.
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3
OFFTAKE TANKER CHECKLISTS Most field operators use a standard checklist. The formats below are generic lists designed for offtake tanker use at Single Point Moorings (SPMs) or in tandem loading. They are not definitive and should be adapted to local use. Arrival Checklist
Vessel:
Loading Point:
Date:
Up-to-date charts of largest scale in use
Offtaker/Installation contingency plans confirmed
All hazards located and marked on charts
Telemetry links (if applicable) established and tested
No go areas marked on charts
Slow down way points established and understood
Passage plan to loading point agreed and in effect
Approach and pick-up plan discussed and agreed with control room and support vessel
Field operating manual/JOPs etc read and understood
Deck machinery operational
Tidal and current data available and checked
Deck crew to stations
Current weather suitable, forecast checked
Pick-up gear tested, inspected and operational
Under keel clearance (including squat) established
Stern towing system (if used) ready
Appropriate Bridge Team assembled and briefed
Required lights/signals exhibited/available
Abort position/circumstances established and understood by Bridge Team
Emergency towing system(s) visually examined and ready for use
Escape routes identified and understood
Anchors cleared for use
Main and auxiliary propulsion operational
Permission to enter Safety Zone from control room
Auxiliary generators and steering operational
Watchkeeping arrangements and responsibilities for loading understood
Engine room checklist completed
Approach and pick-up plan discussed and agreed with control room and support vessel
Appropriate Engine-room Team assembled and briefed
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Arrival Checklist Vessel:
Loading Point:
Date:
All navigation, communications and control systems checked and operational Bridge Team duties assigned Main and auxiliary propulsion tested in both directions Steering gear tested over full range All required navigation and control systems operational Power distribution system in correct mode for DP operations DP system (if fitted) operational DP operators (if applicable) identified, responsibilities understood All radio systems tested operational Contact made with loading point control room Contact made with any support/assist vessels Master:
Date:
Departure Checklist Vessel:
Loading Point:
Date:
Disconnect sequence and departure track agreed and advised to support vessel and control room
DP operators (if applicable) identified, responsibilities understood
Cargo/ballast operations completed
All radio systems tested operational
Deck machinery operational
Abort position/circumstances established and understood by Bridge Team
Deck crew to stations
Commencement of disconnect operations agreed with control room
Emergency towing systems ready for use
Support vessel advised
Charts of largest scale in use
Radios tested and on correct channels
All hazards located and marked on chart
Electronic navigation systems correctly set up
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Departure Checklist Vessel:
Loading Point:
Date:
No go areas marked on chart
Clocks synchronized
Outward passage plan agreed and in effect
Telephones/speakers tested
Field operations/JOPs etc read and understood
Whistle tested
Tidal and current data available and checked
Required lights/shapes exhibited/available
Current weather suitable, forecast checked
Required flags exhibited/available
Escape routes and safe anchorages identified Vessel/Installation contingency plans confirmed Under keel clearance (including squat) established Main and auxiliary propulsion operational Auxiliary generators and steering gear operational Engine room checklist completed Appropriate Engine-room Team assembled and briefed All navigation, communications and control systems checked and operational Bridge Team duties assigned Steering gear tested over full range Power distribution system in correct mode for DP operations DP system (if fitted) operational Master:
Field Checklists Add 5-6
Date:
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4
COLLISION AVOIDANCE FLOWCHART (SBV GUIDELINES APPENDIX 3)
Monitor all traffic within a suitable range
No Does the vessel have a projected CPA of <2nm?
Yes Monitor vessel closely
No
Does the vessel have a projected CPA of <1nm at 6nm off Installation? Yes Continue monitoring vessel. Inform OIM. Attempt radio contact with vessel.
Is radio contact made with vessel?
Yes
No Monitor situation closely and continue attempts to contact vessel. Inform OIM. Call off close standby. Initiate emergency response. Attempt to intercept vessel and warn-off by all available means.
No
Does vessel still pose a collision risk?
Yes Update OIM and prepare for potential Installation evacuation. Continue to monitor situation.
Note: This flowchart uses distance to determine alert/decision points. Time to CPA is recommended in practice.
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Addendum 6 Installation Data Cards
All offshore fields and Installations in the UK sector are required to produce a data card which includes: •
Location
•
Marine hazards of the Installation/field
•
Communications details and procedures
•
Pre-entry checklists required before entering Safety Zone
•
Marine coordination
•
Crane and bulk transfer arrangements
This is an essential tool in the Installation/vessel information exchange and ensures that the vessel is aware of the hazards and peculiarities of the location. (refer to Section 7.5.1 of the OSV Code). The Dutyholder is responsible for providing visiting vessels with the data card. (refer to OSV Code Section 2.2). An example of a data card is given in Appendix 7 of the UKOOA OSV Code.
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Addendum 7 Incident and Near Miss Reporting Formats Below are examples of such formats which should be consulted for possible use where appropriate. Contact the individual organisation to access the format, refer to Addendum 11. 1.
EERVA ‘Warning Off’ Report
2.
Safety Zone Infringement Report OIR 13
3.
IMCA Stationkeeping Incident Report Form: •
Thruster-assisted vessels
•
DP vessels
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Addendum 8 References Including Relevant Codes and Regulations
1
2
3
HEALTH AND SAFETY AT WORK 1.
Health and Safety at Work Act 1974
2.
Statutory Instructions (SIs): •
1992/2885
Offshore Installation (Safety Case) Regulations
•
1995/743
Offshore Installation (PFEER) Regulations
•
1996/913
Offshore Installations and Wells (Design and Construction etc) Regulations
•
1995/3163
Reporting of Injuries, Death and Dangerous Occurrences Regulations
3.
Health and Safety Management Systems Interfacing (UKOOA)
4.
Successful Health and Safety Management, (HS(G) 65) UK Health and Safety Executive October 1993.
COLLISION RISK MANAGEMENT (CRM) 1.
Advice to Inspectors – Collision Risk Management (PBN 00/06), UK Health and Safety Executive March 2000.
2.
Effective Collision Risk Management for Offshore Installations (OTO 1999 052), Health and Safety Executive, January 2000.
GENERAL 1.
Task-based Risk Assessment – Step Change in Safety.
2.
Management of Emergency Response for Offshore Installations (UKOOA)
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4
PASSING VESSELS 1.
5
6
Automatic identification of ships •
SOLAS Regulation V/19
•
IMO Draft Resolution A22/9 Annex 2
ATTENDANT VESSELS 1.
Guidelines for the Safe Management and Operation of Offshore Support Vessels (UKOOA/CoS).
2.
Guidelines for the Safe Management and Operation of Vessels Standing By Offshore Installations (UKOOA/ERRVA/IADC/BROA).
3.
Guidelines for the Survey of Vessels Standing By Offshore Installations (UKOOA/ERRVA/IADC/BROA).
4.
Safety Interface Document for DP Vessel working near an offshore platform (IMCA, M125 1997).
FPSO/FSUS AND OFFTAKE TANKERS 1.
Offshore Safety Loading Guidelines (OCIMF, 1999): •
Section 6 Joint Operations Manuals
2.
Risk Minimisation (Intertanko 2000).
Guidelines
3.
Guidelines for the (IMCA, M103 1999).
Design
4.
Supplement for Two Vessel Operations (IMCA, M161 2001).
5.
Quantified Frequency of Shuttle Tanker Collisions during Offtake Operations (IMCA Report M150 February 1999).
and
References including Relevant Codes and Regulations Add 8-2
for
Shuttle
Operation
Tanker
of
DP
Operations
Vessels
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6.
UKOOA Tandem Loading Guidelines: •
Background Report: – Appendix E Generic Performance Standards for Shuttle Tankers
•
Volume 1: – Appendix B Performance Standards – Appendix C Loss of Position and Failure Event Reports – Appendix D Offtake Tanker Key Personnel Competency Matrices – Appendix E Station Keeping Incident Report Form
•
Volume 2: – Towing Assistance including Performance Standards and Crew Competency
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Addendum 9 Passing Vessel – Ship Collision Assessment
1
ROUTE DATABASES COAST gives the position of the shipping routes utilised by shipping in UK waters and the North Sea, the volumes of traffic, the size and speed of vessels using each route, and the width of the routes. It was developed by CorrOcean Safetec for UK Health and Safety Executive, DTLR and UKOOA. The main data sources used include: •
Port data provided by LMIS (Lloyds Maritime Information Services)
•
Offshore traffic surveys carried out by standby vessels
•
Platform and coastal-based radar systems
•
Information from offshore operators (standby, supply, shuttle tanker details)
•
Information from ferry operators
•
Vessel passage plans
•
Deep sea pilot route details
The main information contained in the database is: •
Route waypoints
•
Route standard deviations
•
Distance of route to a user-defined position
•
Bearing from user-defined position to route
•
Volume of traffic on each route
•
Vessel type distribution on each route (merchant, offshore, tanker, ferry)
•
Size distribution of vessels on each route
The programme may also be linked to a graphical output package that allows the identified routes to be automatically plotted on Admiralty Raster Charting Service (ARCS) hydrographic charts. There is a similar shipping traffic database ‘ShipRoutes’ which has recently been developed by Anatec and accepted by DTLR.
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2
COLLISION MODELS There are several commercial ship/Installation collision models that can be used to calculate the frequency of a passing vessel colliding with an Installation. Those currently available and the organisations which developed them include: •
CRASH
DNV
•
COLLIDE
CorrOcean Safetec
•
COLRISK
Anatec
•
MANS
MSCN (Netherlands)
In part, the collision models use data contained in the shipping traffic database to predict the frequency of a ship/Installation collisions. It is important that the model uses traffic data which is accurate for the existing or proposed location of the Installation under consideration. In general the models calculate collision frequency from: •
The annual number of vessels passing the location on particular shipping routes and their respective proximity to the location
•
The probability of a vessel being on collision course with the Installation
•
The probability that the vessel fails to recover from its collision course
•
The probability that the Installation or ERRV fails to attract the vessel’s attention in time to avoid collision
•
Collision risk reduction measures at the field
Validation of the COLLIDE model predicted 3.77 powered collision up to 1995 and 0.69 drifting vessel collisions. In the same period there were three actual powered collisions and no drifting collisions. The parameters used by some these models have been modified to fit the model’s predictions to historical incident data.
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Addendum 10 Vessel Impacts – Guidance on Loads and Consequences
1
INTRODUCTION This addendum gives a brief overview of impact energies to be used in assessing consequences and directs the user to appropriate references to be used in calculating the effects of vessel impact on the Installation. It also identifies gaps in current knowledge in evaluating the effect of vessel impact on topside equipment. The text applies to fixed as well as floating Installations.
2
LOAD/IMPACT ENERGY The following text applies to the impact of attendant vessels with fixed platforms (such as jackets and jack-ups) and compliant Installations such as articulated columns, semi-submersibles and Tension Leg Platforms (TLPs). They do not apply to shuttle tanker collisions. Energies to be used in FPSO/shuttle tanker collisions are discussed in Paragraph 3.3. Since 1988, it has been standard practice to design for an impact energy of 14MJ for sideways impact and 11MJ for bow or stern impact (References 3, 4, 11, 12, 15). These values are based on attendant/support vessels of 5000t displacement moving at 2m/s. The added mass is assumed to be 0.1 for bow or stern contact and 0.4 for side impact. The impact energy is in the form of kinetic energy of the moving vessel together with its added mass. For smaller or larger vessels, the modified impact energy E in MJ can be calculated using the following equation: E
=
1 2
( M
+
a)
v
2
Where: M = the displacement in tonnes A = added mass of vessel (0.1M for bow or stern impact and 0.4 for side impact) and V = velocity of impact in m/s Note:
For new designs the Norwegian Petroleum Directorate (NPD) Regulations (Reference 14) requires that M and V to be assumed to be not less than 5000t and 2m/s respectively.
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Impact velocity of 2m/s is based on probable velocity achieved during erroneous operation or drifting in significant wave height of 4m. On impact, the vessel and platform will absorb part of the energy as they deform elastically and plastically (and in fracture if there is such failure). The rest will remain as kinetic energy when the vessel and part of the fixed platform move together. At the end of the event the energy spent in elastic deformation will be converted to kinetic as the vessel rebounds. The rebound is largely due to the global bending of fixed platform. In the case of floating units, rebound is less significant. Plastic deformation and fracture can affect structural integrity – and buoyancy/ stability in the case of floating units. They can also affect the integrity of the equipment supported by the affected members or located behind them. As the platform bends and then rebounds, the accelerations at deck level can be significant and equipment can be affected. The following paragraphs briefly consider the effects of vessel impact on structural integrity, equipment and buoyancy/stability.
3
STRUCTURAL INTEGRITY 3.1 Fixed Structures Assessment of structural damage due to impact is normally calculated using the force indentation curves developed by Det Norske Veritas (DNV). They are presented in References 4 and 5. A more recent set of curves are presented in Reference 16. These references also provide guidance in using the curves. They were developed for an impact of a 5000t vessel with infinitely stiff vertical cylinders of 1.5 and 10m diameters. Even though the applicability of these curves is limited, they are still being used widely. Unless it is certain that the use of these of these curves and the analysis method used provides conservative results, it is prudent to ensure that the energy absorbed by the Installation is not less than 4MJ (Reference 11). Detailed methods for calculating damage to leg or braces of jacket structures can be found in References 4, 16 and 19. The methods described in these references can also be applied to jack-up units. Techniques specifically developed for jack-ups can be found in References 5 and 6.
3.2 Semi-Submersibles and Tension Leg Platforms The information given in References 4, 5 and 16 are also useful in evaluating the damage to semi-submersibles and TLPs. The columns are the areas most vulnerable to collision with attendant vessels. These columns generally have higher energy absorption capacity than jackets or the legs of jack-ups. However, structural damage can also affect marine integrity by allowing water ingress Vessel Impacts – Guidance On Loads and Consequences Add 10-2
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and/or causing damage to pipes essential for marine operations. Additionally, collision with bracings should not be discounted.
3.3 FPSOs Analysis of recent collision incidents between shuttle tankers and FPSOs indicate that impact energy of 40MJ is foreseeable. The curves presented in References 4, 5 and 16 cannot be used in designing or checking for collision damage.
4
CONSEQUENCES 4.1 Equipment which can be Damaged or Affected by Collision •
Impacted directly: – Riser, Emergency Shutdown (ESD) valves and in rare cases, conductors are vulnerable in some fixed Installations – Deck equipment located close to possible impact zones is vulnerable in some FPSOs – Hull of an unladen shuttle tanker which projects above the deck of an FPSO as it approaches
•
Equipment supported or shielded by a member damaged by vessel impact: – Risers supported or shielded by chords or braces can be affected by large deflection or failure of the latter
•
Excessive deflection or relative displacements of equipment supports as a result of structural damage
•
Accelerations due to vessel impact sufficiently high to cause damage to equipment supports, the equipment itself or its controls
4.2 Potential Consequences of Equipment Damage •
Escape of hydrocarbons
•
Loss of power
•
Loss of control
•
Loss of stability/buoyancy
•
Loss of emergency systems, such as fire fighting or emergency power
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•
Degradation of EER systems
Often a combination of these consequences occur.
4.3 Assessing the Potential Consequences In order to assess the potential consequences of vessel impact, deck accelerations, the vulnerability and tolerance of various equipment to accelerations, deflections and the relative displacements or rotation of their supports should be known. Investigation of accelerations due to vessel impact on three jacket structures is reported in Reference 10. The accelerations varied between 0.1 to 0.9g depending on the structure and location of impact on the deck. There are no validated, simplified methods to calculate deck accelerations. Finite element models developed for strength analysis are often used. Some such models may not be suitable for dynamic loads. Failure to consider the softening effects of impacted area could also produce unreliable results. Accelerations significantly greater than 0.1g can cause problems for equipment. There are no suitable guidelines available to assess the vulnerability of offshore equipment to such accelerations. A ‘walkdown’ study (Reference 9) can identify equipment, which is obviously vulnerable to lateral loads or accelerations. It cannot identify all potential problems. In the cases below, ALARP principles should be applied to decide whether any modifications or further detailed investigations are justified or not. 1.
2.
When: •
Equipment vulnerability is not fully understood or
•
Consequences of failure are not obvious
When assessing the risks due to equipment failure, if •
Levels of accelerations are not known accurately or
•
Providing robust equipment appears to be difficult or
•
Acceleration levels can not be reduced
Vessel Impacts – Guidance On Loads and Consequences Add 10-4
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5
REFERENCES 1.
Amdahl, Jorgen and Eberg, Ernst: Ship Collision with Offshore Structures, Structural Dynamics-EURODYN’93 Moan et al (eds) 1993 Balkema Rotterdam, ISBN 90 5410336 I.
2.
Dubbers, R.A.W: A Dynamic Approach to Ship Impact Assessments, Structural Dynamics – EURODYN’93, Moan et al. (eds) 1993 Balkema, Rotterdam, ISBN 90 5410336 1.
3.
Det Norske Veritas: Safety Principles and Arrangements (January 2001).
4.
Det Norske Veritas (Veritec): Design Guidance For Offshore Steel Structures Exposed To Accidental Loads (August 1988).
5.
Det Norske Veritas: Strength Analysis of Main Structures of Self-eleveting Units, Classification Notes No 31.5 (February 1992).
6.
Det Norske Veritas: Investigation of the Impact Resistance of Jack-ups, Health and Safety Executive (OTO 98-033).
7.
EATEC Limited: Blast and Shock Induced Vibrations in Offshore Jacket Installations. Health and Safety Executive (OTH 94 430) 1995 , ISBN 0-7176-0937-5.
8.
Ellinas, C E and Walker, A C: Damage on Offshore Tubular Bracing Members, IABSE rolloquium (Copenhagen 1983).
9.
EQE International Limited: Development of Walkdown Procedures and Pilot Study for the Assessment of Topsides Equipment Subject to Blast Induced Vibrations (OTH 93 415).
10. EQE International Limited: Strong Vibration Working Group Phase II JIP: Final Report, Report No 179-04 R-05 Issue 1 (25 May 2000). 11. Health and Safety Executive: Offshore Installations: Guidance on Design Construction and Certification (4th Edition Consolidated Edition) March 1993, ISBN O 11 882116 4. 12. J P Kenny: Protection of Offshore Installations Against Impact, Health and Safety Executive (OTI 88 535) 1988, ISBN O 11 412927 4. 13. Lloyds Register for Shipping: Boat Impact Study, Health and Safety Executive (OTH 85 224). 14. Norwegian Petroleum Directorate: Regulations Relating to Load Bearing Structures in the Petroleum Activities 1998. 15. Norwegian Technology Standards Institution: Norsok Standard, N-003. Revision 1, February l999, Action and Action Effects.
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16. Norwegian Technology Standards Institution: Norsok Standard, N-004 Design of Steel Structures, Design Against Accidental Loads (December 1998). 17. Ronalds, B F: Vessel Impact Design for Steel Jackets (OTC 6384) 1990. 18. Visser, W: Resistance of Jack-up Conductors to Boat Impact, Health and Safety Executive (OTO 98 029). 19. Visser, V (Pim): Ship Collision and Capacity of Brace Members of Fixed Steel Offshore Platforms, Health and Safety Executive, OTO Report 2002.
Vessel Impacts – Guidance On Loads and Consequences Add 10-6
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Addendum 11 Contacts 1
UK OFFSHORE OPERATORS ASSOCIATION Second Floor 232-242 Vauxhall Bridge Road London SW1V 1AU UK www.oilandgas.org.uk
2
UK HEALTH AND SAFETY EXECUTIVE Publications: Health and Safety Executive Books PO Box 1999 Sudbury Suffolk CO10 2WA Tel: +44 (0)1787 881165 OTO research reports: Health and Safety Executive Research Strategy Unit Bootle Merseyside L20 3DL
Fax: +44 (0)151 951 3098
Chemicals and Hazardous Installations Division: Health and Safety Executive Lord Cullen House Fraser Place Aberdeen AB25 3UB Tel: +44 (0)1224 252500 www.hse.gsi.gov.uk
3
MARITIME AND COASTGUARD AGENCY Spring Place 105 Commercial Road Southhampton SO15 1EG UK www.mcga.gov.uk
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