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Crude Calculations 1.Definitions. 1.1 Free water. The measured volume of water in a tank not in suspension with the liquid in the tank at observed temperature. Expressed in cubic meter or/and barrels. 1.2 Total Observed Volume (TOV). The total measured volume of all petroleum liquids,BS&W,and free water at observed temperature. Expressed in cubic meter or/and barrels. 1.3 Gross Observed Volume (GOV). The total volume of all petroleum liquids and BS&W,but excluding free water,at observed temperature. Expressed in cubic meter or/and barrels. GOV = TOV - Free Water 1.4 Net Observed Volume (NOV). The total volume of all petroleum products but excluding free water and BS&W at observed temperature. Expressed in cubic meter and/or barrels. NOV = TOV - Free Water - BS&W NOV = GOV - BS&W 1.5 Gross Standard Volume (GSV). The total volume of all petroleum products and BS&W,but excluding free water corrected by the appropriate volumecorrectionfactor (VCF) for observed temperature and density to a standard temperature. Expressed in cubic meter or barrels. GSV = GOV x VCF GSV = GOV at 15°C/60°F 1.6 Net Standard Volume (NSV). The total volume of all petroleum products excluding BS&W and free water corrected by the appropriate volumecorrectionfactor (VCF) for observed temperature and density to a standard temperature. Expressed in cubic meter and/or barrels. NSV = NOV x VCF NSV = NOV at 15°C/60°F

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1.7 Total Calculated Volume (TCV). The total volume of all petroleum products and BS&W corrected by the appropriate volumecorrectionfactor for observed temperature and density to a standard temperature and all free water at observed temperature. Expressed in cubic meter and/or barrels. TCV = GSV + Free Water 1.8 Bottom Sediments and Water (BS&W). Quantity of sediments and water into the total amount of petroleum products. Expressed as a percentage as determined by tests. 1.9 Observed Temperature. Temperature of cargo measured at various places in the tank.Mean tempera- ture is determined. 1.10 Standard Temperature. Temperature of 15°C in the metric system,or 60°F in the American system. All volumes must be converted to this temperature before comparing.

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2. Relationship : density , specific density , API Gravity. Gravity is a mass-per-unit-volume relationship. With petroleum products the relationship is expressed as specific gravity. The following definition applies : mass of given volume oil at t° kg Specific gravity = ---------------------------------------------- --- mass of equal volume water at t° kg Temperature normally equal to 60°F or 15°C. Specific gravity is sometimes called relative density oil density at 60°F kg/l Relative density 60/60°F = ----------------------------- ----- water density at 60°F kg/l Specific gravity is being replaced by density expressed in kg per m³. The following definition applies : mass of given volume of oil kg Density of oil at t°C = --------------------------------------- --- volume of oil at t°C m³ In the USA the API gravity is being used. API gravity is an arbitrary scale, calibrated in degrees and related to the specific gravity by the following relation : 141,5 API gravity = --------------------------------- - 131,5 Specific gravity 60/60°F

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3. Mass and weight relationship. 3.1 Mass. The mass of a substance is the quantity it contains.It is independant of external conditions.In oil measurement, it is often referred to as weight-in-vacuo. The metric unit is the kg where 1000kg equals 1 metric tonne. Following relationship applies : mass of oil = volume of oil at t°C x oil density at t°C 3.2 Weight. The weight of a substance (called weight-in-air) is the mass which a substance appears to have when weighted in air. The weight is calculated using the following equation : weight of oil = volume of oil x weight correction factor 3.3 Weight Correction Factor (WCF). The weight correction factor must be obtained from the appropriate table in the Petroleum Measurement Tables. In the American system the WCF can be obtained from table II "Long tons per barrel at 60°F against API gravity at 60°F". In the metric system the WCF can be obtained from table 56 "Kilograms per liter at 15°C and liters at 15°C per metric ton against density at 15°C". The WCF can be easily obtained by subtracting 0.0011 kg/l from the density at 15°C. Unfortunately it is much easier to subtract than to consult Table 56.This has led to the problem that it is no longer obvious which density is used : the density or the WCF. 4.Unit Conversion. Units can be easily interchanged by using the appropriate table from petroleum measure- ments Table Vol XI "Entry with API" or Vol XII "Entry with Relative Density". It is extremely important however to be aware of the following fact : "Like can only be compared with like". Comparasion between volumes and capacities must be done at the same temperature.

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5.Cargo Calculations. 5.1 Metric system. Schematic layout of calculations. Observed density 53A Density @ 15°C

in vacuo 56 WCF in

air

Ullage Waterdip Temperatures Ullage Tables Tt + Tm + Tb= Tm

3

TOV Total

m³ observed volume) Free H2O

m³ MT

54A TOV-H2O VCF

(Volume corr.

GOV (Gross

m³ observed volume)

GOV * VCF GSV (Gross m³ standard volume) Oil mass in vacuo GSV*density @ 15°C GSV*WCF GSV GSV

MT GSV m³

Weight in MT H2O MT

+H2O m³

-ROB/OBQ MT -ROB/OBQ m³ in air TCV MT TCV m³

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Notes : - Given : TOV - Free Water - Temperature and Observed Density - Can be calculated : 1) weight in air in MT (and in LT if needed) 2) weight in vacuo ( = oil mass) - Tables used : 53A - 56 - 54A - The relationship between barrels and cubic meters is very precise if same temperatures are used. 1 Bbl = 0.158987 m³ 1 m³ = 6.28981 Bbls - Temperatures : see "Calculating Representative Cargotemperatures". - Free water : m³ x 1.025 = MT (if seawater) Example : - TOV : 100000m³ at 30°C Density : 0.8520 at 15°C VCF from Table 54A : 0.9873 WCF from Table 56 : 0.8509 - GSV = 100000 x 0.9873 = 98730 m³ - Weight in vacuo = 98730 x 0.8520 = 84117.96 MT ( = oil mass ) - Weight in air = 98730 x 0.8509 = 84009.36 MT General remark concerning metric calculations: In the metric system both weight in air and weight in vacuo can be easily calculated. But this can lead to confusion if calculation form is not clearly labelled. Table 53A: Generalized crude oils.Correction of observed density to density 15°C. Table 54A: Generalized crude oil.Correction of volume to 15°C(against density at 15°C). Table 56: Kilogram per liter at 15°C and liters at 15°C per MT against density at 15°C.

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5.2 American system. Schematic layout of calculations : 11 API 13 WCF in

air

Ullage Waterdip Temperatures Ullage Tables Tt + Tm + Tb= Tm

3

TOV *6.28981 m³ Bbls

Free H2O m³ MT LT *6.28981 Bbls

6A TOV-H2O VCF

GOV

Bbls

GOV * VCF GSV Bbls @ 60°F GSV*WCF (LT/Bbl = T.11 MT/Bbl = T.13) GSV GSV LT GSV Bbl Weight in LT H2O LT +H2O Bbl -ROB/OBQ LT -ROB/OBQ Bbl in air TCV LT TCV

Bbl

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Notes : - Temperature : see " Calculating Representative Cargotemperatures". - Oil weight is calculated ( weight in air ) : oil mass can only be calculated by converting API to density and to preform the metric system calculation. - For calculations in LT table II must be consulted for calculations in metric ton table 13. - If in LT the free water must also be converted to LT. ( LT = MT x 1.016047 ) - The calculations for LT are the most accurate. Example: - TOV = 100000 m³ - TOV = 628981 Bbls at 86°F API 34,49 - VCF from Table 6A : 0.9877 - WCF from Table 11 : 0.13309 - WCF from Table 13 : 0.13520 - GSV = 628981 x 0.9877 = 621244.54 Bbls - Weight in air = 621244.54 x 0.13309 = 82681.4 LT = 621244.54 x 0.13520 = 83992.3 MT (If formula for LT / MT - conversion is being used, a tonnage of 84008.2 MT is found a difference of about 16 MT) Used as guide: - Essomarine conversion tables and charts. - BP publication of Lionel Downer. - Shell publication Januari 1980 Cargo Calculations.

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T E R M S A N D D E F I N I T I O N S ============================================ FREE WATER --------------- The measured volume of water present in a container which is not in suspension in the contained liquid at observed temperature. TOTAL OBSERVED VOLUME - T.O.V. ------------------------------------------- The total measured volume of all petroleum liquids, BS&W, and free water at observed temp. GROSS OBSERVED VOLUME - G.O.V. -------------------------------------------- The total volume of all petroleum liquids and BS&W, excluding free water, at observed temp. TOV - free water NET OBSERVED VOLUME - N.O.V. ----------------------------------------- The total volume of all petroleum liquids excluding BS&W, excluding free water, corrected by the appropriate volume correction factor for the observed temperature and API gravity to a standard temperature of either 60degF or 15degC. GOV corrected to a Standard temperature. NET STANDARD VOLUME - N.S.V. ----------------------------------------- The total volume of all petroleum liq.excluding BS&W and free water, corrected by the appropriate volume correction factor for the observed temperature and API gravity to a standard temperature of either 60degF or15degC. NOV corrected to a Standard temperature. TOTAL CALCULATED VOLUME -T.C.V. ---------------------------------------------- The total volume of all petroleum liquids and BS&W, corrected by the appropriate volume correction for the observed temperature and API gravity to a standard temperature of either 60degF or 15degC and all free water measured at observed temperature. GSV + free water.

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THE WEST OF ENGLAND 07/10/82 =================== C R U D E O I L C L A I M S ---------------------------------- We set out below the various guidelines we feel should be followed with regard to crude oil cargoes. Generally we would point out that there is little law on this subject but because of the size of possible claim we feel it worthwile to take what maybe considered to be excessive precautions and records of all transactions. It should also be pointed out that the vessel's Master should not be suspectible to pressure from the terminal Operators. The first preliminary point is that the Charterparty must be carefully examined to see if a ROB and/or loss retention clause is incorporated in the Charterparty. These clauses, although phrased in many different ways, give the Charterer the right to deduct from the freight an amount equal to the CIF value of apparent shortlanding as against the Bill of Lading. If a loss occurs on the account of such clause alone and represents a liability greater than that imposed by the COGSA, the vessels Club may be prejudiced. Pre-Loading voyage ================== The cargo tanks should be spot checked for sediments as heavy build up will hamper proper drainage. A proper record of all cargo related equipment and all controls and tests made should be kept. It should be possible for the cargo to be loaded not exceeding 98% of the tanks capacity and without any risk of contamination either to the cargo itself or, with regard to the loading temperature of the cargo, to the vessel,s tank coating. The amount of slop and free water should be measured and noted. Retain the ship/shore factor (the experience factor) for the last 5 to 10 voyages and this should be provided to the loading terminal. Loading ======= Before starting to load the terminal Supervisor should be invited to inspect the tanks for dryness and a dry tank certificate should be obtained and signed. If this is not possible a refusal to sign should be notidied on the certificate with the reason, time and terminal Supervisors name and a copy given to the terminal. This should be done in all situations where the terminal refuses signatures or certificates. Ullaging if possible should be by automatic tapes and taken to the nearest one quarter inch or 0.5cm. Before arriving at the terminal check if the inert gas seal is to be broken alongside the vessel. If not invite the Receivers to make a gauging before mooring and write a letter of protest if they did not attend. The vessel should take its own measurements and place them on record. Temperatures are to be taken at the upper,middle and lower third - midpoint levels,preferably by digital temperature reading tape. The API received from shore should be used and a temperature observed on board. If the API later is found to differ from the Bill of Lading density the cargo quantity should be recalculated. On the ullage form,the tables used for calculations should be identified and

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deductions made for slops/water and sediment. The cargo must be checked for water at commencement of loading, drawing samples from the manifold and if water is found the terminal should be notified immediately and a letter of protest handed to them. When the cargo has been received on board the API should again be checked and ships samples of the cargo secured if possible in the presence of the terminal operator. If the ships quantity exceeds the Bill of Lading figures by more than 0.3% a protest letter to the cargo supplier/or the terminal should be given. Again a protest letter should always be given if the on board quantities are less than the Bill of Lading figures plus the experience factor Early departure procedures should be avoided if posible but if they are used the cargo suppliers, terminals, Charterers and Receivers of the cargo should be notified of any cargo discrepancies. The Agent should not be authorised to sign Bills of Lading if the ships on board quantities are less than the Bill of Lading figures (which will usually be the shore figures) but a request should be made for the insertion of the ships figures and the Owners P & I Club consulted. Voyage ====== The sea valves are to be secured in the loading port and if possible the terminal Representative should verify the number on the seals. This information should be entered into the ships official log with date and time and indeed any discrepancies or difficulties should be entered in the ships log at all times. During the voyage the ullages will be checked and recorded frequently particularly if trimming of cargo becomes necessary Discharging ports ================== Before breaking bulk the terminal Representative is to be invited to attend the gauging which will be carried out by the Chief Officer or well experienced officer. Under no circumstances should the shore personnel be allowed to do their own gauging except as an odd check and then always closely supervised. Gauging will be carried out twice, the first time using the ships equipment and making notes of any discrepencies on the vessels ullage sheet and again after calibration of the equipment has been carried out. Again if the surveyor is unwilling to allow his tapes to be calibrated this should be noted in the official logbook and a letter of protest given to the terminal. On no account should discharge be allowed to occur if the readings differ more than a quarter of an inch or the temperature increases more than 0.5degC. Temperatures are to be taken at the same time as ullages but no more than 4 hours before the ullage of the last tank is taken. Discharge is only to occur when ISS pressure is up to normal level. Before discharging commences a pre-discharge conference with the terminal Representative should be held particularly identifying all sections of the discharge and emergency shut down procedures. An entry in the official logbook of the name of the terminal Representative attending to the vessel should be made. A thorough record of the discharge operation such as opening- closing of valves, the pumps run, the pressure, the suction readings, rpm of the pumps, line ups, checking of ullages, manifold pressure, etc. should be kept and readings noted at least every hour or when there is a change affecting the operation.

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A note should also be kept of the time of the various operations. Re-stripping of the tanks should be done simultaneously with the discharge and no doubt if it is necessary to ballast empty tanks whilst simultaneously discharging of proper line strip will be done and the tanks completely drained of cargo and this fact verified by terminal Representatives. An attempt should be made to obtain written permission to ballast and a dry tank inspection certificate. Again if this is not possible the refusal should be noted in the record with the time, date and name of the Representative. In order to ballast, the seals on the seachest are to be broken under the supervision of the Representative. On finishing discharge when the ullages indicate the tanks are empty these should be verified by the terminal Representative and a dry tank certificate signed assuming the Representative is entitled to do this. If not, a note should be made. If the gauging of the tanks is undertaken and the residue is said by the terminal to be pumpable" the records should be signed without prejudice or for receipt only and if possible the vessel's own remarks should be inserted. The Master should refuse to take the vessel off the terminal and refuse to disconnect the cargo hoses. A letter of protest should be handed to the terminal inviting the Representative to watch the running of the pumps to the tanks in question. The time and result of the test and the names of the persons attending or refusing to attend should be noted and then a new protest letter given to the terminal setting out the results of the test and describing the ROB as unpumpable with the ship's equipment, all being in good running order. If the cargo hose is to be blown/drained into the vessels tanks another protest letter should be given to the terminal and the Authorities put on notice that any oil drained from the lines into the tanks will result in a high ROB for which the vessel is not responsible. In brief, the vessel should never leave the discharging port if the ROB is classed as "pumpable" or as"cargo" if present immeasurable quantities without consulting the Owner and P & I Club. The basic advice may therefore be said to be that records of all calculations should be kept not only for the current voyage but for the vessels previous voyage. As many documents as possible should be obtained and recorded as oil shortage claims are in reality claims on paper. We thrust that these comments will assist Owners in their future voyages. J.E.Pemberton THE WEST OF ENGLAND SHIPOWNERS INSURANCE SERVICES LIMITED.