cargo loss

7/29/2019 cargo loss

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CARGO CLAIMS AND LOSSES ON CHEMICAL TANKERS -- CAPT AJIT VADAKAYIL

AVOIDING CLAIMS AND LOSSESRead this PRACTICAL points carefully, so that you may save your company from financial claims andembarassment.Encourage every crew member to talk about their mistakes, so all can learn from them. This is the way tobuild a winning team. Cargo work involves team work dynamics and is not a one man show. Shipboard losses can be from--Evaporation via PV vents.Deliberate retention for ulterior motives.Excessive ROB due to high pour-point of cargo or pumping problems.On Paper Only virtual losses : In many shortage claims no actual loss has taken place but the amount of cargo has been overstatedwhen loading and/orunderstated when discharging.To avoid large vapour losses, is the Reid vapour pressure (RVP) of the cargo within the ships PVcapacity?Company policy often dictates the filling limit. 98% of a tanks capacity generally allows for cargotemperature to increase by 20C - but the difference in temperature between northern Europe and thetropics often exceeds this figure. Imagine a cargo of Pentane loaded from LeHavre to US gulf.Ullages exceeding limits set out in the ships stability book can lead to excessive free surface. This cancause sloshing, makingpressure/vacuum valves breatheand resulting in vapour losses or boil off of thelighter fractions of the cargo. This dynamic sloshing stress can cause structural failure and endanger thecrew/ ship.Stowing volatile cargo next to heated cargo causes evaporation losses. Charterers should specifymaximum adjacent temperatures. AH is an important spec on chemical tankers.Chief officer must find out:--Number of shore tanks to be loaded from, the quantity, temperature and SG of cargo in each.Whether there are any planned loading stops for shore tank changes. Whether density is being expressed in air or in vacuumWhether shore pipelines are full or empty, and details of any pipeline displacements planned.Whether loading by gravity or shore pumps.
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Whether pumps are displacement ( screw ) or non- displacement ( centrifugal ) . Topping up is easy withgravity loading and centrifugal pump loading as valves can be throttled. Only a non-displacement pumpcan tolerate the ship shutting valves while it is pumping.While in some trades the discharge ports out turn figures alone determine the amount of cargo delivered,in others they are still compared to the bill of lading figures provided by the loadport.Even if both terminals carry out their measurements diligently, each will (quite legally) round offtemperature and ullagereadings in its favour, so differences are only to be expected. In the absence of alike-for-like comparison, the ship is the only common factor - and therefore the measurements taken onboard are critical. The inspector must be accompanied at all times and his ullage measurements activelyverified.Measurement errorsoften result from commercial pressures. Remembering that, long after the immediatepressure has been forgotten, the ship will remain responsible for having ensured that the measurementswere carried out correctly. Some owners employ cargo superintendents ( supercargo ) to relieve thepressure. If, in spite of all measures taken, an early departure procedure, for example, exposes the shipto any unwarranted liability, she must protest.Use of defective equipment-- frequently maintaining and checking ships equipment - and arranging

forregular calibrationof electronic measuring devices by an agent approved by the manufacturerimproper measurement technique--- doing homework, sharing experience around and encouragingeveryone to talk about their mistakes, so all can learn from them.Never permit the use of the terminals measuring equipment on board. If measurements taken withthe inspectors equipmentdiffer from those taken with the ships, propose that all measurements be takenwith each, and both be sent for verification ashore afterwards.If the retro-fitted vapour lock valves required by electronic gauging equipment have changed the heightand/or position of the ullage point, measurements taken through such valves must be corrected beforeuse. This Vapor lock reference measurement( can be found in P@A manual ) should be posted in CCRbulkhead prominently.If the ship is pitching or rolling, five measurements should be taken, withdrawing the tape as soon as itpenetrates the surface of the cargo. The highest and lowest should be ignored and the middle threeaveraged. Weather and sea conditions should be logged. In the same conditions on inerted ships, or where electronic, closed gauging equipment is used, theprobe should be withdrawn and lowered until three readings differ by no more than 5mm.Taking cargo temperature: The temperature of every cargo tank should be recorded separately.Cargo temperaturemay vary by 5 C at different levels in the tank, so must be averaged from at leastthree readings -top, middle and bottom. Some digital probes can measure at more frequent intervalsA measurementerror of 1C can distort the volume calculation by +/-0.1%, depending on cargo density. Checking cargo densityChecking cargo density. Despite practical difficulties, it is best practice to make sure the density of thecargo is measured and compared with the figures supplied by the terminal. If the loading terminalmeasures densities in vacuum and the discharge port in air, the figures must be corrected to avoid anapparent loss . A difference of 0.0100 Kg/litre in cargo density can alter a VLCCs tonnage calculation bysome 3,000 metric tonnesAllowing fortrim/ list: Many loadport cargo measurement errors are caused by failing to make dueallowance for trim and list. These should be based on draft readings whenever possible.


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Free water: The quantity of any free water detected must also be corrected for trim and list. Protest evensmall amounts, as there is likely to be more in suspension. Cargo calculations: Make sure all parties are using the same edition of the ASTM PetroleumMeasurement tablesfor mineral cargoes. Make sure ASTM tables are NOT used for organic chemicals. Ifthe surveyor insists , then make a remark . Ensure disport also uses the same tables. Make sure the contents of the ships pipelines are included in the calculations.Sign the inspectors quantity report for ullages and temperatures only.Apply the vessel experience factor(VEF).If the ships figures differ from the shores, review the calculations. If the difference is confirmed, initiatethe owners standard procedure.Cargo surveyor: Accompany the inspector at all times, ensuring that he measures temperatures, ullages,densities, list and trimaccurately.Ullaging active tanks regularly and comparing results with hourly shore discharge rateshelps ensure thatcargo is not being misdirected / divertedin the receiving terminal.Monitoring air and sea temperature and sea state can provide valuable evidence in case of a subsequentdispute about the pumpabilityof the cargo. Most shore pipelines are not heated or lagged.Stripping The best way to avoid losses resulting from charter party freight retention clauses is to makesure the ship can demonstrate it did everything possible to discharge all the cargo. Provided it is withinthe ships stress limits, the greater the trim aft, the better the drainage, especially with high MP andviscous cargoes.When stripping high pour-pointcargo: Maintain cargo at the recommended discharge temperature untilthe heating coils are about to be exposed start stripping as soon as cargo pumping stops. Protest any

request from the shore to stop. If the stop is essential, continue stripping to an accumulation tank andresume cargo heating as soon as possible.When stripping high vapour pressurecargoes: Avoid operating pumps at excessive speed whichincreases vaporisation, causes cavitation and reduces suction. Increasing the pressure of inert gas in thecargo tank or increasing the back pressure on the pump can improve pumping performance. Re-inspectempty tanks before declaring a grade finished.ROB determination:Additional cargo may have accumulated due to:Changes in list and trimBulkhead, pipeline or valve leaks difficulty of calibrating bottom levels of tanksBlocked limber holes, on inner frame tanksUnmeasurable tank side clingageUncertainty about the liquidity of bottom residuesIt is always important to observe and log precisely how the inspector measures ROB. Ensure he surveysall the cargo tanks. Make sure he takes great care reading sounding rods or bobs, to avoid the commonmistake of overstating the liquid element of bottom residues because it has run down over the sedimentas the rod is raised.Ask him to take samples of the bottom residue, from more than one point in each tank if possible.


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If you suspect that the samplesmay be unrepresentative because of the tendency of less viscousmaterial to flow more easily into the sampling device, ask the inspector to sample the more viscousmaterial found in the pump mud box or the manifold when it is disconnected.Urge that the wedge formulabe applied only to the liquid element of the ROB, since it can be argued thatthere must be as much sediment under the liquid as there is in the dry parts of the tank. Ensure that the tank dry certificate states that All pipelinesare stripped dry. Do not allow the shore hosesto be disconnected until the inspector has signed a dry tank certificate, or a statement of ROB, that youagree with. If you dispute the inspectors figures, initiate company standard procedure.Calculate the ROB independently, compare results with the inspectors and log any differences.CONTAMINATION:In the contest against claims, as in todays competitive market place, only the best informed will win.Approximately 45% of alleged shipboard contamination problems are, on investigation, found to be shorerelated.ShoresideResidues of previous contents of storage tanks, lines and hoses. Tank and line cleaning media, including water. Other products, because of valve leakage or mis-operation or poor in-line blending.Fresh water or impurities carried over from the manufacturing process.Fresh water from leaking heating coils or tank roofs.Salt water from leaking sub-sea pipelines.ShipboardResidues of previous contents of ships tanks, lines, pumps and hoses.Dirty sounding and ullaging equipment.Tank coating deficiencies.Tank and line cleaning media, including water. Other part cargoes, because of valve leakage, valve mis-operation or tank structural deficiency (e.g.bulkhead cracks).Other part cargoes vapour via common inert gas systems.Salt water from leaking tank hatch domes, butterworth ports , sounding pipes and vents.Fresh water from leaking heating coils.Copper leaching from alloys used to manufacture heating coils on CPP ships (e.g. alloy brasscontamination of jet fuel).Is the tank coating suitable for the cargo? For example white wine needs stainless steel; epoxy ispreferred for vegetable oils.Some cargoes can permanently damage certain coatings, others make coatings soft for a while, duringwhich time the range of cargoes they can tolerate is restricted. Refer to the coating manufacturers

resistance lists.For multi-grade loadings, plan the use of pumps and pipelines to avoid or minimise commingling ordowngrading. Ensure line displacements are calculated such as to avoid cross-contamination.If ullages are insufficient, cargo from one tank can slosh through a common vent lineto contaminate non-compatible cargo in an adjacent tank, if the ship rolls or pounds. The vapours of one grade can put another grade out of specification, e.g. gasoline and kerosene ordiesel, if the VRS spoolsare not disconnected.


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Heat reduces the effectiveness ofinhibitors, so avoid stowing inhibited cargoes adjacent to heated tanks. The Chief Officer must ascertain the following from the terminal representatives-whether the shore pipeline is dedicated--details of any shore pipeline displacementsplanned number ofshore tanks to be loaded from, and the quantity, temperature and density of cargo in each. Whether anyloading stops are planned for shore tank changes, whether ship or shore is responsible - and how tostop in an emergency.If changes are to take place without stops, that the ship receive notification of every change for samplingpurposes.Whether the ship will be receiving two sets of samples from the shore tanks: one for the receiver, one forthe shipowner(if not, log that the request was made and refused) Cargo surveyor:--Remember, an independent inspector is independent in name only - expect him to give the shipsinterests low priority, and make sure he is accompanied by an officer at all times.An experienced officer may well be more expert than the inspector, who is usually a non-marine personor even a ex-junior officer.Tanks cannot be entered where local regulations insist on constant operation of the inert gas system but,whenever possible, make sure that the inspector checks every tank thoroughly. If the ships pipelines have been drained, demonstrate this to him and ensure it appears on the inspectioncertificate.Outside the chemical trade, tank inspections are often subjective so, if you do not agree with theinspector, try to reach a commercial solution always faster and cheaper than a legal one.As soon as it becomes apparent that you cannot agree, protest.Sampling: Adopt a sampling procedure that satisfies the relevant authorities.Make sure the ship has the right equipment, including clean bottles, seals and labels. Label sampleswith the following information:Ships name, date and timeLocation, cargo nameOperational status (e.g. after loading)Sample source (e.g. tank number...)Sample type (e.g. top; composite)Identity of samplerSeal numberMake sure each sample is signed and sealed, preferably by the independent inspector. Note theparticulars of every sample taken for the ships purposes in a sampling log. Present the inspector with alist of samples drawn and retained by the ship for acknowledgement and signature. Require any party towhom a sample is handed over to sign a receipt for it. Store samples in a secure space which is cool, well ventilated and not exposed to light. Since the Hague Rules allow claims to be presented up to a year after the event, samples should not bedisposed of until that period of time has elapsed.


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Samples showing that the condition of the cargo did not change between loading and discharge providethe best defence against unfounded contamination claims.If the lab report is to be right, the sample must be right too - an inspector is as prone to error as the nextman.The inspector must be accompanied at all times, to ensure that the sampling procedure satisfies therelevant authorities.If the inspector fails to do something he should, or does it wrong, point it out to him, and log anything hedoes not put right.Log any faults with his equipment and any occasions when he borrows the ships. As well as any samples he takes for the consignee, the receiver and his own firm, ask the inspector totake another set for the ship. If he refuses, note it in the log - and take your own.Chief Officers should ensure they receive two sets of shore tank samples for each grade: one set fordelivery to the receivers agent; the other to be retained by the ship.Asking the inspector to take starting samples at the manifold is the best way to detect contamination orcommingling in shore lines.Make sure first foot samples are taken to verify that the ships lines are clean. Discourage the inspector from subjecting them to visual analysis only, while loading continues.Loading should be stopped while proper tests are carried out, particularly when the specification is critical.If the samples are off-test, advise the charterer without delay.Even if tests reveal no problems, the ship must retain its duplicate samples in case of any later dispute. Carry out spot checks at the manifold whenever practicable during loading, particularly after any shorestops andpreferably accompanied by the inspector or a representative of the terminal.Accompany the inspector when he opens the sealed unit of any composite sampler.After-loading samples should be taken from top, middle and bottom of each cargo tank.If the cargo is to be treated with an additive, the fact should be recorded on the bill of lading. Unless youare certain that the shipper and receiver have agreed to this taking place after loading, require any partyproposing to do this to sign for receipt of a letter protesting the procedure - before he carries it out.Make sure you receive a certificate in respect of cargoes that are inhibited. At the discharge port, in-line samples of each grade of cargo should be taken at the manifold:- at the start of discharging- once during every watch that the grade is being discharged - during stripping- If the inspector fails to take any of these samples, the ship should take its own. - Make sure the inspector samples any free water found, so that its source can be established. - Sampling gas oil bunker tanks after loading and before discharging helps defend against claims thatcargo has been used asbunkers.


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Maintain a minimum of two-valve separation throughout the discharge of multiple grade cargoes. Onchemical tankers, unnecessary spols are removed and blanked.Valves should be sealed (if they were not sealed in the loadport) and the seals pointed out to theinspector and logged.If possible, leave seals in place until discharge is completed and ask the inspector to note the fact. The most easily contaminated grades should be discharged first, if possible. If any grade cannot toleratecontact with residues of the grade before, strip the cargo line. If necessary, flush the line with the secondgrade and re-strip - it is better to lose part of the cargo through downgrading than to contaminate all of itand the shore tank besides.A watch officer discovering contamination should:- stop discharging the relevant cargo- close that systems valves- advise the Chief Officer, who advises the Master, who contacts the owner and his local P&Icorrespondent.The Master should:- sample the remaining cargo and request testing- await instructions from the ownerCrew must never try to conceal a operational error which may result in contamination. The soonerproblems are identified, the less the owners potential exposure.Remember-- on chemical tankers ( unlike oil tankers ) we take manifold sample --WITHOUT opening themanifold valve--for obvious reasons..

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