CARGO CALCULATIONS
Cargo calculations
The volume of cargo on board can be determined by means of soundings or ullage measurements and calibration tables (tank tables) The purpose of the cargo calculations is to convert the observed volume into weight Calculation of trim, stability, freeboard, shear forces, bending moments is based on weights On the B/L the quantity of cargo is stated as a weight (Metric Tons , Long Tons, Short Tons, Pounds, etc. )
Cargo calculations
The volume of cargo on board can be determined by means of soundings or ullage measurements and calibration tables (tank tables) The purpose of the cargo calculations is to convert the observed volume into weight Calculation of trim, stability, freeboard, shear forces, bending moments is based on weights On the B/L the quantity of cargo is stated as a weight (Metric Tons , Long Tons, Short Tons, Pounds, etc. )
•
When making the stowage plan a lot of information has to be gathered, a lot of factors have to be taken into account
•
Cargo calculations are important because they are the link between the available space and the weight to be loaded
Cargo calculations on board of a gas carrier
Cargo calculations
The volume of cargo on board can be determined by means of soundings or ullage measurements and calibration tables (tank tables) The purpose of the cargo calculations is to convert the observed volume into weight Calculation of trim, stability, freeboard, shear forces, bending moments is based on weights On the B/L the quantity of cargo is stated as a weight (Metric Tons , Long Tons, Short Tons, Pounds, etc. )
Cargo calculation maximum filling limits
IMO specifies maximum filling limits as follows: V l = 0.98 V dr/dt V l is the max volume to which the tank can be loaded V is the total volume of the tank D is the density of the cargo at ref. temperature r Reference temperature = boiling temperature at relief valve setting pressure (the highest temperature that can be reached during the voyage, highest temperature = smallest density) D t is the density of the cargo at the loading temperature PS. Liquefied gas is always transported at the boiling temperature, at this temperature liquid and gas are in equilibrium. Boiling temperature is determined by the pressure in the tank. Boiling temperature rises with the pressure and the pressure will never get higher than the relief valve setting.
Cargo calculation maximum filling limits Example: Fully ref. vessel loading propane at –42°C. Relief valves set at 0.25barg (bar gauge = relative pressure) Absolute pressure: 0.25+1.0 = 1.25 bar Ref. temperature (corresponding to SVP, Saturated Vapour Pressure, 1.25 bara for propane) = -37°5C dr = 0.5765 @ -37°5C Density of liquid propane Density of liquid propane d = 0.582 @ -42°C t V =0.98 V 0.5765 / 0.582 = 0.97 V l Thus tanks can be filled to 97%
Units of volume
1 U.S. Gallon = 1 U.S. Barrel = 1 U.S. Barrel = 1 Imperial Gallon= 1 Cubic feet = 1 Cubic meter =
3.78541 Litre 158.987 Litre 42 U.S. Gallons 4.54596 Litre 28.3169 Litre 6.28981 U.S. Barrel
Units of weight
1 Long Ton 1 Short Ton 1 Long Ton 1 Pound
= = = =
1.01605 Metric Ton 0.907185 Metric Ton 2240 Pounds 0.453592 Kilogram
Units of density
Density is the relation between mass (weight) and volume True and apparant density Relative density and specific gravity Litre weight API
Temperature conversion Degrees Celsius: C° Degrees Fahrenheit: F° Degrees Kelvin: K ° 0°C = 32°F & 100°C = 212°F °F=(°C-32)x 5/9 =>
°C
= (°F x 9/5) + 32
Cargo calculations
The relationship between the volume and the mass/weight can be expressed by: Density True density Apparent density Specific gravity Litre weight API gravity
Cargo calculations The relationship between the volume and the mass or weight can be expressed by the density (specific gravity, litre weight, API, relative density etc.) Density and volume change in function of the temperature The weight of a cargo is of course independent of the temperature but the weight in air (apparent weight) the weight in vacuum (true weight)
Density Fundamentaly 3 Density: Unit of mass per volume [kg/m or kg/litre ] When calculating cargo True density: Weight per unit of volume in vacuum Apparant density: Weight per unit of volume in air
Mass Mass is the only SI unit not based on the fundamental atomic properties or the speed of light Reference standard is a small platinum cylinder with a mass of 1 kg made in 1880 and kept under inert conditions at the Bureau International des Poids et Mesures near Paris
Cargo calculations
Mass (massa )is a measure of the quantity of material in a body and is constant regardless of geographical location, altitude or atmospheric conditions
Weight
is the force with which a body is attracted to the earth and varies from place to place with « g », the acceleration of gravity
Standard ???? “g” = 9,81m/sec2 2 Weight = Mass x 9,81m/sec
Cargo calculations All commodities are sold by weight and this means weight in air. The term « weight » in general practice has been accepted as being the value secured when an object is weighed in air This weight or « weight in air » is often converted to « weight in vacuum » by the application of an air buoyancy correction (vacuum factor)
Principle of Archimedes
Physical law of buoyancy, discovered by the ancient Greek mathematician and inventor Archimedes, stating that any body completely or partially submerged in a fluid (gas or liquid) at rest is acted upon by an upward, or buoyant, force the magnitude of which is equal to the weight of the fluid displaced by the body.
Principle of Archimedes
Principle of Archimedes A ship that is launched sinks into the ocean until the weight of the water it displaces is just equal to its own weight (). As the ship is loaded, it sinks deeper, displacing more water, and so the magnitude of the buoyant force continuously matches the weight of the ship and its cargo.
Principle of Archimedes P = Weight F = Force of Archimedes The ship floats if P = F If P > F => Submarine (ballast) If P < F => Air balloon (hot air or a very light gas f.i. hydrogen)
The bathescafe sinks because his own weight (light weight + ballast) > the weight of the water it displaces The Zepplin flies because his own weight (hydrogen gas is very light) < the weight of the air displaces.
Density and kg/m3 in air
Density is defined as « mass per unit volume », expressed in direct terms of mass and volume (kg/m3, kg/lit). In simple language, density is the weight of a unit volume of the substance, weighed in the absence of air Density varies as temperature changes and is therefore expressed at a specific temperature (15°C) Density is sometimes referred to as « true density » or « density in vacuum » and will consequently give us « true mass »
Density and kg/m3 in air
The conversion between true density and apparent density can be carried out with table 56. The most commonly encountered HC fluids need a negative correction of 1,1 kg/m3. m3 Calculations of quantity by means of kg/m 3 will give apparent mass (weight) instead of true mass (weight)
Relative density, Specific gravity and API Relative density and (American Petroleum Institute) API-gravity are commonly used in British and American publications. Relative density replaces the widely known term « specific gravity » which has been formerly used in the oil industry.
Relative density, Specific gravity and API Relative Density15/15C
Specific gravity 60/60F
Mass of a given volu me of substance at 15C Mass of an equal volume of pure water at 15C
Mass of a given volu me of substance at 60F Mass of an equal volume of pure water at 60F
API gravity at 60F
141,5 Rel. Dens. 60/60F
131,5
Relative density, Specific gravity and API Relative Density15/15C
Specific gravity 60/60F
True weight a given volu me of substance at 15C True weight equal volume of pure water at 15C
True weight a given volu me of substance at 60F True weight an equal volume of pure water at 60F
Relative Density – Specific Gravity Apparent Relative Density – Apparent Specific Gravity Relative density 15° /20° = Weight in vacuum of a given volume prod. at 15°C/ Weight in vacuum H 2O same volume at 20°C /20° = Apparent Relative Density 15° Weight in air given volume of prod. at 15°C/ Weight in air H2O same volume at 20°C
Relative density, Specific gravity and API
It should be noted that relative density (spec. grav.) is expressed as a ratio and no physical units are involved. It is possible to convert f.i. spec. grav. 60/60°F to density at 60°F by the following relationship Density substance at 60°F [kg/m3] = spec. grav. 60/60°F x 999,04 [kg/m3] (density H2O at 60°F)
True and apparent density of water at different temperatures T C
True Density
Apparent density
4
1.00000
0.99888
15
0.99913
0.99805
15.56 (60 F)
0.99904
0.99796
20
0 99823
0.99717
25
0.99707
0.99604
50
0.98807
0.98702
°
°
Litre weight
Weight in AIR of 1 litre of substance at a given temperature
Conversion factors
Rel. Dens. 20/20 C
=
( vacuum factor X litre weight ) / 0.99823
Rel. Dens. 15.5/15.5 C =
( vacuum factor X litre weight ) / 0.99905
Rel. Dens. 25/25 C
=
( vacuum factor X litre weight ) / 0.99707
Rel. Dens. 60/60 F
=
( vacuum factor X litre weight ) / 0.99903
Rel. Dens. 25/4 C
=
( vacuum factor X litre weight ) / 1.00000
Rel. Dens. 20/4 C
=
( vacuum factor X litre weight ) / 1.00000
Rel. Dens. 15/15 C
=
( vacuum factor X litre weight ) / 0.99913
°
°
° °
° °
°
Approx. vacuum factors
Liter weight 1.0 Liter weight 0.9 Liter weight 0.8 Liter weight 0.7
-
1.00108 1.00122 1.00139 1.00161
ASTM 54 - LPG
Volume and density corrections Weight = volume x density Only true if volume and density are known at the same temperature 3 solutions 1) Correct the volume to the temperature of the density VCF = Volume correction factor Volume correction to 60°F or 15°C 2) Correct density to the temperature of the volume DCC = Density correction per degree centigrade 3) Correct both to the same reference temperature, 60°F or 15 °C
Volume and density corrections Both factors are based on the same physical phenomenon. Fluids or solids expand when heated but the mass or weight remains unchanged => the density decreases Relation between change in temperature and change in volume is expressed by the coefficient of volume expansion
Relation between density and temperature Coefficient of volumetric expansion is not linear – see curve. Curve is described by the ASTM-VCF tables. For a small temperature range curve can be replaced by tangent line. Inclination of this line is better known as the DCC coefficient DCC = Density correction per degree centigrade
Examples of DCC factors Acetone Caustic Soda (50%) Ethanol Glycerine i-pentane Latex
-
0.00114 0.00070 0.00079 0.00063 0.00097 0.00100
Volume correction factor The VCF factor (VCF) converts a volume or a density of a fluid at ambient temperature to a reference or standard temperature (15° (15°C or 60° 60°F) VCF factors are published in special tables – ASTM-tables – ASTM-tables
ASTM = American American Standards on Technical Technical Measurements
Example ASTM tables
ASTM tables Table No Table 5A Table 5B Table 5D Table 6A Table 6B
Description Correction of observed API gravity to API gravity at 60°F (gen. crude oils) Correction of observed API gravity to API gravity at 60 °F (gen. Products) Correction of observed API gravity to API gravity at 60 °F (gen. Lub. Oils) Correction of volume to 60°F against API gravity at 60°F (gen. crude oils) Correction of volume to 60 F against API gravity at 60 F (gen. products) VCF for individual and special applications Correction of volume to 60°F against API gravity at 60°F (gen. lub. oils) °
°
Table 6C Table 6D
ASTM tables Table No Table 23A Table 23B products) Table 24A Table 24B
Description Correction of observed relative density to relative density 60/60 °F (sen. crude oils) Correction of observed relative density to relative density 60/60 °F (gen. Correction of volume to 60°F against relative density 60/60 °F (gen. crude oils) Correction of volume to 60 F against relative density 60/60 F (gen. products) VCF for individual and special applications °
°
Table 24C
ASTM tables Table No Table 53A Table 53B Table 54B
Description Correction of observed density to density at 15°C (gen. crude oils) Correction of observed density to density at 15°C (gen. products) Correction of volume to 15 C against density at 15 C (gen. products) VCF for individual and special applications Correction of volume to 15°C against density at 15°C (gen. lub. oils) °
°
Table 54C Table 54D
Vol XI and XII contain 58 conversion tables
EXXON BUNKER COLCULATION TOOL
Cargo calculations going from total observed volume to weight in air using VCF Met ullage en trim ga je in tanktabellen en vind je het geobserveerde volume. Dit is zonder rekening te houden met temperatuur of densiteit. Vervolgens ga je met trim en dip nog eens in de tabellen en heb je berekend hoeveel water er onder je lading zit. Hiervoor wil niemand betalen en ze wordt dus met het geobserveerde volume vermindert. Zo bekom je het gross observed volume. Vervolgens doe je een aanpassing voor de temperatuur en de densisteit, je vindt zo de VCF factor, deze moet je met de gross observed volume vermeerderen. We bekomen zo ons volume. Als we nu nog een omzetting naar vacuum moeten doen, dan komt hier nog een vacuumfactor bij. Enkel met vacuum werken als men de hoeveelheden aan de wal bekend maakt, voor de rest verder werken in air.
Cargo calculations on board of a gas carrier
Calculations are somewhat different from the calculations on board of an oil- or chemical carrier On board of a fully- or semi refrigerated gas carriers temperatures are very low. These low temperatures have an influence on the volume of the tank itself and on the the ullaging equipment, being the floater and the perforated tape (in case of a mechanical ullaging device)
Cargo calculations on board of a gas carrier In a loaded gas tank an equilibrium exists between the cargo in the liquid phase and the cargo in the gas phase. Consequently a not negligible part of the cargo is gaseous All the above mentioned facts make a gas calculation somewhat more complicated
Cargo calculations on board of a gas carrier On discharge one normally retains sufficient cargo on board to keep the tanks cooled fore the next loading quantity loaded/discharged = quantity o/b on arrival - quantity o/b at departure Therefore calculations before AND after every loading or discharge operation
LNG - calculations
LNG is traded within long-time projects with dedicated production, transportation and reception facilities LNG-carriers use the boil-off during loaded and ballast voyages as ship’s fuel Commercial quantification is usually done on the basis of the calorific value of the cargo delivered. Calorific calculations are based on liquid volume and density at tank conditions
Shore measurements versus ship measurements Shore
tank measurements are not as accurate as ship measurements Shore
tanks have a greater cross-section => greater relative error During cargo handling operations a certain pressure has to be maintained in the shore tanks => vapours of different origins can be used. Vapour
flow from other shore tanks Liquid vaporisers Vapour return line from the ship =>
Exact vapour quantity is difficult to calculate.
Shore measurements versus ship measurements Vapour quantification ashore is difficult Some terminals, therefore, use a simplified approach. The weight-in-air of the liquid change in the shore tank is evaluated from measurements before and after transfer and 0.43 % (only for propane and butane in fully ref. condition) of the weight-in-air of the liquid transferred is subtracted or added to account for the vapor weight replacing the liquid transferred.
Shore measurements versus ship measurements
It is common practice to use ship’s figures to determine cargo volumes (contrary to crude or chem. trade where shore figures are used) Some customs authorities require the ship’s tanks to be calibrated by an approved classification society or by suitable independent cargo surveyors (custody transfer)
Shore measurements versus ship measurements On loading it is important to take account of the density of the remaining cargo (liquid heel in each tank). If this is appreciably different from the cargo to be loaded => the density in the tanks after loading may be affected An independent cargo surveyor will be appointed to verify ship & shore volume measurements (ship-shore difference)
Cargo calculations on board of a gas carrier Liquefied
gas cargoes are carried as boiling liquids in equilibrium with their vapour in closed containment systems
The
vapour phase above the liquid cargo must be calculated and included in the total cargo quantity
Cargo calculations on board of a gas carrier Total quantity of cargo is equal to the sum of : 1. 2.
Quantity of cargo in liquid phase Quantity of cargo in vapour phase
Liquid cargo calculation volume determination Innage or sounding is measured on gas tankers, ullage on other tankers
Mechanically operated float gauges
Mechanically operated float gauges
Sonic systems
Sonic systems
Liquid cargo calculation volume determination A
calibration table is provided for each cargo tank, giving for each sounding the corresponding volume this table has been drawn up under
ambient conditions with the vessel being in upright position (no trim, no list) Therefore corrections must be applied to obtain a CORRECTED SOUNDING
Liquid cargo calculation volume determination Corrections: temperature
corrections
Tape
correction Float correction not
upright ship corrections
Trim
correction List correction
Liquid cargo calculation volume determination
Low temperatures have an influence on
the ullaging equipment, being the floater and the perforated tape (in case of a mechanical ullaging device) the volume of the tank itself
Liquid cargo calculation volume determination Tape The
correction or dip correction:
float gauge tape passes through the cold vapour space Depending on the temperature it will contract It will therefore indicate a lower liquid level then actually present Tape correction should be added to the liquid level read
Liquid cargo calculation volume determination Float
correction:
The
zero of the float gauge is determined by the manufacturer Immersion of the float depends upon the cargo density If cargo temp. and density are different from that assumed by the manufacturer’s zero determination a small correction for float immersion is required
Liquid cargo calculation volume determination List
correction
depending on the actual list depending on the position of the liquid indicator on the cargo tank list is indicated in degrees
Liquid cargo calculation volume determination
In an upright position, liquid level and ships bottom are both horizontal. No correction has to be applied
Liquid cargo calculation volume determination Depending upon the position of the liquid indicator a list correction has to be applied
Volume in the tank has not changed A
B
C
A’
B’
List = 0°
List = 5°
A=B=C
A’ > A B’ = B C’ < C
C’
Liquid cargo calculation volume determination Trim
correction depending on the trim position of the ship depending on the position of the level indicator on the cargo tank trim is expressed in metres (centimetres)
Liquid cargo calculation volume determination
If the ship is even keel, the liquid level is parallel to the keel. No trim correction in this condition
Liquid cargo calculation volume determination If the ship is not even keel, the horizontal liquid surface is not parallel to the keel anymore. The liquid level will be different depending on the place of measurement
Liquid cargo calculation volume determination Sounding
observed
Dip p Di
or ta tape pe cor corre rect ctio ion n float actual
sounding
list trim
corrected
sounding liquid volume
Liquid cargo calculation volume determination Shrinkage The
factor:
cargo tank is calibrated at ambient temperature (mostly 20° 20°C) If cold cargo is loaded, the tank will have a lower temperature and therefore a smaller volume Different corrections are applied to liquid and vapour phases because of different temperatures
Liquid cargo calculation volume determination
Liquid
volume
x shrinkage factor actual
liquid volume
Liquid cargo calculation mass determination observed sounding dip and float correction
actual sounding list and trim correction
corrected sounding liquid volume at temperature
shrinkage factor
observed volume ASTM D 1250 - table 54 B VCF correction (old)
ASTM D 2598 - table table 53 B density at cargo temperature
density tables from an official surveyor (f.e. SGS) density at cargo temperature
standard volume x density at 15°C
liquid mass
liquid mass
1
2
3
Cargo calculations going from total observed volume to weight in air using VCF
Vapour cargo calculation volume determination Vapour volume = total tank volume - liquid volume due to low temperatures in the tank, the total tank volume has to be corrected, by using the shrinkage factor for the mean (or weighed ) temperature in the tank
Weighed average tank temperature Weighed average tank temperature = ((liquid height x liquid temp.) + (gas height x gas temp.))/Total height of the tank. Used to obtain the shrinkage factor for the complete tank
Vapour cargo calculation mass determination Due to cargo operations, vapour and liquid are not in equilibrium in the tank therefore gas density cannot be obtained from the tables we will use the ideal gas law and Avogadro’s law
Vapour cargo calculation mass determination Basis: The ideal gas law P 1V 1 T 1
P 2V 2 T 2
The gas in a standard situation (P = 1013mbar en T = 288K) is compared with the gas in the tank atmosphere
Some definitions
MOLE = also spelled MOL, in chemistry, a standard scientific unit for measuring large quantities of very small entities such as atoms, molecules, or other specified particles. The mole designates an extremely large number of units, 6.0221367 x 1023, which is the number of atoms determined experimentally to be found in 12 grams of carbon-12.
MOLE or MOL
Carbon-12 was chosen arbitrarily to serve as the reference standard of the mole unit for the International System of Units (SI). The number of units in a mole also bears the name Avogadro's number , or Avogadro's constant, in honour of the Italian physicist Amedeo Avogadro (1776-1856). Avogadro proposed that equal
volumes of gases under the same conditions contain the same number of molecules, , a hypothesis that proved useful in determining atomic and molecular weights and which led to the concept of the mole.
Avrogadro’s law
Under the same conditions of temperature and pressure, equal volumes of different gases contain an equal number of molecules. The volume occupied by 6.0221367 x 10 23 The volume occupied by one gram-mole of gas is about 22.4 l at standard temperature and pressure (0°C, 1 atmosphere) and is the same for all gases. 22.4 l/mol at 0°C or 273K becomes 23.645l/mol at 15°C or 288K
Ps.Vs
Pv.Vv
Ts Tv Ps 1013mbar Ts 288K (15C) Vs
n.I
n aantal mol I 23.645l/mo l Pv absolute pressure in the tanks Tv temperature in the tank expressed in K Vv n.Mm/Dv M m molecular weight in kg/mol Dv density of the gas Ps.n.I
Pv.
Mm.n
Dv Ts Tv Ts Pv M m Dv
Purpose = to calculate the vapour density at the observed temperature Starting point = the ideal gas law A volume gas = number of moles X the volume of 1 mole = 22,4l/mol if temp. 273K(0°C) or 23,645 if temp. 288K A volume gas also = (number of moles x mulecular mass)/
Example Volume vapour in the tank = 29.952m 3 Temp = -30°C = (273K-30°C = 243K) Pressure = 0.1bar relative = 1.1bar absolute Mm = 44.1 kg/kmol
288K 1100mbar 44.097kg / kmol dv x x 243K 1013mbar 23.645m3 / kmol dv = 2.4 kg/m3
Vapour cargo calculation weight determination Vapour volume x vapour density = vapour weight
cargo calculation weight determination
Liquid weight + vapour weight = total cargo weight
Cargo calculations - data Product Innage Trim List Liq.temp Gas temp Vapour space pressure Molecular weight Density at 15°C
Propane 10.020 + 2m 0.5° P -43°C -38°C 59 mbarg 44.097 511 kg/M3
Ship’s calibration tables Trim correction List correction Level gauge correction Float immersion correction Corrected innage Volume at calibration temp 100% at calibration temp Volume vapour space at cal. temp. Shrinkage –43°C Shrinkage –38°C
-127mm + 46mm + 1mm 0mm 9.940m 5.441,88M3 9.893,63M3 4.451,75M3 0.99773 0.99791
INNAGE corrections
Trim correction
List correction
Innage – 127mm
Innage +46mm
Liquid Calculation Liq.vol. at cal. temp. Shrinkage factor Volume liquid at –43°C VCF –43°C -> 15°C Volume at 15°C Density at 15°C (vac)
Mass
5.441,88m3 0.99773 5429.52 m3 1.145 6.216,8 m3 511 kg/ m3 3.176,785 T
Vapour Calculation Vol.vapour at calib.temp Thermal factor Vol. at –38° Dens. at –38°C (see slide) Mass Vapour Total Mass Weight in air factor ( ASTM 54) Weight in air
4451,75 m3 0.99791 4442.45 m3 2.389 kg/ m3 10.613 T 3.187,398 T 0.99775 3.180,23 T
Vapour density calculation
= 2.389 kg/M3
Dynamic Flow Measurement
Some modern terminals are being equipped with sophisticated liquid and vapour flow metering with associated in-line sampling. The equipment presently is expensive and requires complicated proving arrangements. However, this method allows flow rate and density to be continuously recorded at the flow temperature and, by combining these outputs electronically, mass flow rate can be provided and integrated to give total mass transferred.
Ultrasonic flow measurement
Quantity calculations on board of LNG carriers
The quantity discharged is measured by an ultrasonic flow measurement device Ultrasonic meters have no moving parts, they suffer no pressure loss and they provide maintenance-free operation - important advantages over conventional mechanical meters such as positive displacement meters (PDs), turbines, orifice plates and vortex meters
Quantity calculations on board of LNG carriers
Ultrasonic flow measurement uses the transit time principle, whereby opposite sending and receiving transducers are used to transmit signals through the flow. The signal travels faster when moving with the flow stream rather than against the flow stream. The difference between the two transit times is used to calculate the flow rate. Measuring principle – Doppler effect
Operating principle
Metering Unit on board of the Excalibur
•
Ultrasonic type flow meter and gas chromatograph
•
Applied extensively on land based plants (incl. Custody Transfer Systems on land)
•
No moving parts => very reliable
Gas Chromatography
Used to establish chemical composition of the gas and the derived values such as density and caloric value of the sample
Cargo documentation
B/L is the most important cargo document Enables the cargo receiver to assess if the proper quantity has been discharged Before departure from the loading terminal the shipmaster should ensure that the B/L quantities accurately represent the cargo loaded The master should be sure that cargo calculation records made at loading and discharge are properly prepared
Bill of Lading A
Bill of Lading is a document signed by the shipmaster at the port of loading. It details the type and quantity of cargo loaded, the name of the ship and the name of the cargo receiver. The
Bill of Lading has three functions. It is:
The
shipmaster's receipt for cargo loaded A document of title for the cargo described in it Evidence that a Contract of Carriage (such as a voyage charter party) exists
Bill of Lading
By signing the document, the shipmaster attests to the apparent good order and condition of the cargo loaded. By signing the Bill of Lading, the shipmaster agrees to the quantity of cargo loaded In some circumstances, where the Bill of Lading quantities do not match the ship's figure, the shipmaster may be expected to issue a Letter of Protest at the loading port.
Bill of Lading
Whoever possesses the Bill of Lading rightfully owns the cargo. The old practice of issuing three original Bills of Lading has been largely superseded and now it is common to find only one being issued. Should a cargo be sold before it reaches its destination, the Bill of Lading must be endorsed by the original cargo buyer to show the new cargo owner.
Bill of Lading
Due to delays in banking or trading chains, an endorsed original is not always to hand at the discharge port. Accordingly, as an alternative to presenting the original Bill of Lading to the ship master, a receiver may issue a Letter of Indemnity (LOI) to the ship.
B/L
Certificate of Quantity A Certificate of Quantity is issued by the loading terminal as, or on behalf of, the shipper and the cargo quantities declared as loaded may be verified by an independent cargo surveyor. The certificate is of assistance to the shipmaster in determining the quantities to be inserted in the Bill of Lading. However, the quantities as stated on the Bill of Lading remain the official record of the cargo as loaded.
Certificate of Quantity
Certificate of Quality A Certificate of Quality provides the product specification and quality in terms of physical characteristics (such as vapour pressure and density) and component constituents. It is issued by the loading terminal as, or on behalf of, the shipper or may be issued by an independent cargo inspection service. Again, the data contained in the document assists the shipmaster in signing the Bill of Lading.
Certificate of Quality
Certificate of Origin A Certificate of Origin is a document issued by the manufacturer or shipper, counter-signed by the customs authorities, which attests to the country in which the cargo was produced. It may be required by financial authorities in the importing country so that they may assess import taxes or grants. Unlike the previous two certificates, it is not complementary to or supportive of the Bill of Lading but its distribution to shipper, carrier and cargo receiver is similar.
Time Sheet
The Time Sheet records all salient port-times, from a ship's port entry until final departure. The Time Sheet is usually prepared by an independent cargo surveyor or the ship's agent and is checked and countersigned by the shipmaster and the shore terminal. Its purpose is to provide an agreed statement of facts relating to the timing of events and delays during the ship's port call and is used to facilitate demurrage claims.
Time sheet
NOR
Cargo Manifest A Cargo Manifest is usually prepared by the ship's agent at the loading port or by the shipmaster and lists all cargoes according to the Bills of Lading. Its purpose is to provide readily available data for customs authorities and ships' agents in the discharge port. The appropriate preparation of the Cargo Manifest is controlled by the SOLAS & FAL convention.
Certificate of tank fitness A Certificate of Tank Fitness is usually issued by a specialist chemist from a cargo surveying company and is issued where particular tank cleanliness conditions are required prior to loading.
Certificate of Inhibitor Addition An Inhibitor Information Form is issued by the loading terminal or by the cargo manufacturer.
