IntroductionAccording to the UN’s Food and Agricultural Organisation, there are morethan 28 million people engaged infishing operations worldwide. The annualworld catch of fish exceeds 100 million tonnes, of which around 25 per centis processed into frozen fishery products. Each year, a high proportion ofthese frozen products enters international trade and is carried by sea.

Sometimes cargoes of frozen products are found to be damaged whenthey are unloaded from ships and rejected, leading to claims againstshipowners and agents alleging that the damage is due to negligence onthe part of the masters and crews of the carrying vessels.

Clearly a vessel is not liable for damage that was sustained before loading,or during handling if due to the actions of third parties. Frequently it isdifficult to establish the precise cause and chain of events leading up to thedamage. Specialised knowledge is required to sample and inspect fisheryproducts, and relate their condition to the events of the voyage. However,vessel operators also need adequate technical knowledge to minimise therisk of problems occurring, and to act in the event of a claim.

These guidelines are intended to advise ships’ masters, officers and crewon good practices to be observed during the loading, storage, carriage anddischarge of frozen fishery products carries as bulk cargoes. They alsoprovide detailed guidance on how vessel operators can limit their liability fordamage, by ensuring adequate pre-shipment inspection and by actingpromptly to preserve evidence when a problem occurs. Other sections alsoprovide background information on factors which affect the condition offrozen fish cargoes during trans-shipment and transport and advice on howto spot signs that a fish cargo is running into problems.

Factors which affect the condition of frozen fish cargoes duringtrans-shipment and transport and advice on how to spot signsthat a fish cargo is running into problems.

Carefully to CarrySEPTEMBER 2006

UK P&I CLUB

Frozen fish on reefer vesselsand in containers

Carefully to CarryAdvisory Committee

This report was produced by the Carefullyto Carry Committee – the UK P&I Club’sadvisory committee on cargo matters.The aim of the Carefully to CarryCommittee is to reduce claims throughcontemporaneous advice to the Club’sMembers through the most efficientmeans available.

The committee was established in 1961and has produced many articles oncargoes that cause claims and othercargo related issues such as holdwashing, cargo securing, and ventilation.

The quality of advice given hasestablished Carefully to Carry as a keysource of guidance for shipowners andships’ officers. In addition, the articleshave frequently been the source ofexpertise in negotiations over thesettlement of claims and have also beenrelied on in court hearings.

In 2002 all articles were revised andpublished in book form as well as on disk.All articles are also available to Memberson the Club website. Visit the Carefully toCarry section in the Loss Prevention areaof the Club website www.ukpandi.comfor more information, or contact the LossPrevention Department.

“The carriershall properlyand carefullyload, handle,stow, carry,keep, care forand dischargethe goodscarried.”

Hague Rules,Articles iii, Rule 2

Frozen fishery productsTypes of frozen fishery products

A variety of frozen fishery products are carried by sea inreefer vessels and reefer containers. The main types, inapproximately descending order of frequency are asfollows:

Whole, gutted1, or dressed2 fish individuallyfrozen1. Gutted fish are whole apart from removal of the viscera.

2. Dressed fish have heads and guts, and perhaps tails and fins removed

Tuna intended for canning is a typical example.

Fillets are either placed in packages for retail sale orloosely packed in plastic bags. Small display packs arepacked in outer cartons while loosely packed fillets maybe packed in bags within outer cartons.

Cephalopods, frozen in blocks or as packagedproductsThese include squid, cuttlefish and octopus. Bothprocessed and unprocessed products are typicallyfrozen in blocks weighing 10 or 25kg. Blocks areoccasionally individually packaged, but more usuallyare overwrapped in plastic with several blocks beingpacked together in a single outer carton.

Whole fish individually frozen

Whole, gutted, or dressed fish in blocksThis is a common form of presentation for small andmedium-sized fish intended for further processing.Blocks are rarely more than 10cm thick or more than50kg in weight. Common sizes are 25 and 50kg.Blocks are either unwrapped or wrapped in plastic filmand are sometimes packed in strapped cartons.

Fillets of fish, frozen in a block, wrapped and packed in a carton

Fillets of fish frozen in blocksFillets of fish are often frozen into geometrically shapedblocks. Blocks are usually wrapped in plastic film andpacked into inner display packs. The display packs arethen commonly packed in outer cartons.

Fillets of fish, individually frozenThese are fillets frozen as separate pieces, andperhaps then coated with batter, or batter andbreadcrumbs.

Cephalopods(squid) frozen in blocks

Crustacean shellfish, frozen in blocks or aspackaged productsThese include lobster, crayfish, shrimp and crab.Smaller crustaceans and crustacean meats are oftenfrozen in blocks weighing up to 1kg. Blocks are packedindividually in cartons or over-wrapped in plastic filmand then packed into outer cartons.

Crustacean shellfish, individually frozenLarge crustacea, for example lobsters and crayfish areindividually frozen, whole or as tails, wrapped andpacked in cartons.

Freezing and storage of fisheryproductsIntroduction

The master of a vessel carrying frozen fishery productsdoes not generally need to be concerned with howthe products have been frozen and stored beforedelivery to the vessel. Indeed, he has no means ofknowing or verifying these conditions, except perhapswhen fishery products have been prepared and frozenat sea and transhipped directly to the carrier vessel.However, the quality of the cargo discharged from thevessel is affected by freezing, storage and distributionpractices before transfer to the vessel, as well as bythe manner of loading, stowage and carriage on thevessel.

The following is intended to inform masters and crewabout the technologies involved in freezing andstorage of frozen fishery products, and the effects offreezing and storage on product quality.

The freezing process

When a fish product is cooled in a freezer itstemperature drops rapidly to about -1oC, when icebegins to form. However, not all the water in the fishturns to ice at this point. As more heat is extracted,more ice forms, but the temperature of the productdrops only slowly until about -3oC. This period, whenthe product temperature changes very gradually, isknown as the ‘thermal arrest period’.

The product’s temperature then begins to drop rapidlytowards the operating temperature of the freezer.(Fig A)

When the product is allowed to thaw, the temperaturewill follow a curve similar to Figure A, but in thereverse direction. oC, then slowly to about -1oC as itpasses through thermal arrest, then rapidly again untilthe product reaches the ambient temperature.

It is important for the quality of the frozen product thatthe thermal arrest period is as short as possible,preferably less than two hours. This rate of cooling canonly be achieved in equipment designed for thepurpose – merely placing fish in a cold store will notachieve a sufficiently high freezing rate. Therefrigerated holds of reefer ships are designed as coldstores to maintain the temperature of already frozenproducts; they do not have the refrigeration capacity tofreeze products at the required rate.

fishing vessel is fitted with one or more insulated tankscontaining refrigeration coils. Before fishing starts,these tanks are filled with sea water, which is thencooled to around 0oC. As fish are caught, they aredropped into the tanks. When a tank is full, salt is addedto lower the freezing point of the brine and thetemperature is lowered so that the fish freeze. Thetemperature that can be achieved depends on theconcentration of the brine – the minimum, when thebrine is saturated, is about -21oC. In practice, fishingvessels aim for a solution giving a temperature ofaround -12oC. Once the fish are frozen, the brine isdrained from the tank and the fish are held in drycondition with the refrigeration system on.

Freezing of blocksSmall products, including small fish, fish fillets, squid,octopus and shrimps, are often frozen in blocks. Theproduct is laid in trays and frozen, either in a tunnelthrough which cold air is passed or between pairs ofhollow plates through which refrigerant is circulated.The frozen block is knocked out of the tray, protectedby some form of over-wrapping and perhaps packedinto cartons.

The quality of frozen fishery products

Quality of productsComplaints about defects in the quality of frozen fisherycargoes usually fall into one or both of two categories:

● Abnormal and offensive odours, flavours or texture,or any other defects that will influence theconsumers’ perception of quality.

● Physical damage affecting the processability ormerchantability of the product (can occur during thefreezing process, though more usually happensduring handling of the frozen product).

Quality defects in both categories can arise duringhandling, processing and storage of the product beforedelivery to the vessel, during loading into the ship’sholds, and while the product is stored on the reefervessel.

Loss of quality can occur both before and after freezing.However, the nature of the defects differs in the twocircumstances and an experienced assessor should beable to distinguish between them.

Loss of quality before freezingFish of all kinds are notorious for the speed at whichthey spoil (even when chilled) and for the unpleasantnature of the spoiled product. Spoilage affects theappearance, odour and flavour of the product. Freezinghalts the spoilage process and fixes the quality as it wasat the time of freezing. When frozen products arethawed out, the quality can be no better than it was at

Fig A. Freezing curve of fish initially at 5oC

5

0

-5

-10

-15

-20

-250 1 2 3Hours in freezer

4

Pro

duct

tem

pera

ture

(Cel

sius

)

THERMAL ARREST PERIOD

Examples of freezing methods

Brine freezing of individual fishBrine freezing is used for larger, whole fish like salmonand tuna. The technique is used almost exclusivelyonboard fishing vessels, particularly tuna-catchers. The

the time of freezing. If defects in the quality of frozenfishery products at time of delivery are shown to be aconsequence of spoilage, then no blame can beattached to the carrier of the frozen goods unless theproduct had thawed out during the voyage.

Loss of quality during frozen storageFrozen fishery products are not completely stable in thefrozen state and will deteriorate over time, resultingin changes in texture, odour and flavour of the product.Changes in texture are similar in character across mostfishery products – the product becomes dry, stringyand tough. But changes in odour and flavour depend onthe type of fishery product. Lean fish with low oilcontent (such as cod) develop the characteristicodours and flavours described as ‘musty’, ‘cardboard’,and ‘wet dog’, while fish with high oil content (like tuna,herring and mackerel) develop rancid odours andflavours reminiscent of new leather, linseed oil or old-fashioned oil paints. Odour and flavour changes infrozen crustacean shellfish and cephalopods are similarto those in lean fish. Oily fish deteriorate faster, andproduce off-odours more quickly than lean fish duringfrozen storage.

The main factors influencing the rate at which fisheryproducts deteriorate during frozen storage aretemperature of storage and exposure to air. The lowerthe storage temperature the slower the productdeteriorates. The storage life of fishery products carriedat -18oC ranges from 3 to 12 months. In general,storage life is halved for each 5oC rise in storagetemperature. For example, a product with a storage life8 months at -18oC will have a storage life of 4 months at-13oC. Since ship’ refrigeration systems can maintainproducts at temperatures below -18oC, and sincevoyages are generally less than a month long, thereshould be no significant loss of quality due to frozenstorage-related defects during a voyage.

Rate of deterioration is also affected by exposure to air.Block-frozen products are usually protected by closewrapping with plastic film or by coating with a waterglaze. To maintain quality, it is important that this cover,film or glaze is not damaged or lost.

Another defect arising during frozen storage isexcessive loss of moisture from the product, whichleads to general or localised dehydration known as a‘freezer burn’. The dehydration is signified by whitepatches which appear where glaze is lost or wherethere are tears or breaks in the protective wrapping. Inunprotected material, dehydration occurs first in thinparts of the product such as the fins of the whole fishand the tail-ends of fillets, or at the corners of blocks.These dried areas do not re-hydrate when the productis thawed and are indicated by blemishes in the thawedproduct.

Physical damage to frozen productsPhysical damage takes a number of forms, butcomplaints about the quality of reefer cargoes areusually concerned with distortion or compression of theproduct. This kind of damage, which affects individuallyfrozen fish or blocks of products, occurs when warmfishery products (i.e. warm relative to therecommended storage temperature) are subjected topressure, for example in a stack of fish stored in theship’s hold.

When water is frozen, it changes from a liquid to a hardsolid, ice, at 0oC. Although fish typically contain70-80% of water – the exact percentage depends onthe species – the situation is more complicated thanfreezing water alone. Water in the fish tissues starts tofreeze at about -1oC but at this point only a proportionof the water is converted to ice. Progressively, morewater freezes as the temperature falls. At -18oC, themaximum temperature usually specified for carriage offrozen fish in reefers, around 90% of the water hasturned to ice. It is very hard to deform frozen fish at thistemperature and below, except under extremely highpressure.

If the product warms at all, some of the ice melts. Thefish tissue holds an increasing proportion of liquid waterand a decreasing proportion of ice as its temperaturerises.

Indentations caused when warmed, soft tuna were pressed on toridged floor plates by the weight of the stack of fish above them

As the proportion of ice decreases, the fish tissue,though still partly frozen, becomes softer and can bedeformed by moderate pressure. For example, it ispossible to deform the surface of a product at -7oC bypressing hard with the point of a pen, a temperatureprobe, or even a thumbnail. At -3oC, ‘frozen’ fisheryproducts are soft enough to deform and to sag undertheir own weight. If the cargo in the hold of a reefer isstacked to a height of 4 or 5 metres, as is often thecase, there is sufficient pressure to distort fish to someextent at -7oC, and to distort and compress fishconsiderably at -5oC or higher.

Individually frozen fish can be severely indented wherethey lie across each other, and tend to take up theshapes of the surfaces they are pressed against –ridged floor plates or edges of structures in the hold. Inan extreme case, a stack of fish can be compressedtogether into a solid mass, with almost no spacesbetween the fish. Blocks of products are squeezed,flattened and distorted and will extrude into gapsbetween cartons, they can also be indented by floorplates or pallet boards.

Frozen products at low temperatures are often brittleand prone to damage by rough handling. For example,tails are easily broken off whole fish and blocks can beshattered or chipped.

Products can also be damaged by contamination. If oilor chemicals are spilled, they may penetrate thewrappings and affect the contents. When cartons andwrappings are torn, the contents are more vulnerable toboth contamination and dehydration.

Pre-shipment inspectionThe need for inspection

Loss of quality in fishery products can be caused bydamage both before and after freezing. Carriage offrozen fish by sea is just one stage in a long sequence ofprocessing, handling, distribution and storageoperations – products can be damaged or decline inquality at any stage. Receivers of damaged cargoes offrozen fishery products might allege that loss of qualityoccurred solely while the material was in the chargeof the shipowner.

Pre-shipment inspection is therefore essential, todetermine as far as possible the condition and quality ofthe product at the time of loading, and to note anycircumstances that could lead to an exaggerated loss ofquality during carriage in the vessel. Such informationhas an important bearing on any claim that loss ofquality or damage occurred during carriage in thereefer. The inspection should take into account thenature of the material, its packaging and itspresentation.

Pre-shipment inspection by the ship’s officers isgenerally confined to visual inspection of the cargo andto measurement of physical properties such astemperature. Officers are not expected to carry outdetailed evaluations of the quality of the material, whichwould require examination of material after thawing andperhaps also after cooking.

Nature of the consignment

The deck officer should check that the materials to beloaded are consistent with the bill of lading. However,

information provided on a bill of lading is usually verybrief – a cargo may be described as ‘fishery products’,which encompasses many different product types.Wherever possible, deck officers should record anyadditional information, for example, in the case ofindividually frozen fish, the species or variety, thepresentation (whole or dressed) and the name of thefishing vessel.

It is also important to record the details of any labellingon wrapped or cartoned material, particularlyproduction dates or batch codes. The absence of anylabelling, particularly of batch or production codes,should also be noted.

Information on the nature of the consignment and alldetails of labelling should be recorded on the mate’sreceipt. If labels are detachable, one can be removedand attached to the receipt.

Temperature of the consignment

It is essential to measure the temperature of frozen fishpresented for loading. Since fishery products sufferdamage if they are stowed at a high temperature,temperature records provide important evidence of thestate of the product at the time of loading.

The terms of carriage normally stipulate thetemperature, or at least the maximum temperature, atwhich the cargo should be carried. Holds of reefervessels are intended for storage of frozen materialloaded at the required temperature of carriage.Refrigeration systems have little spare capacity tolower the temperature of products which are put intothe hold at above its operating temperature. Materialthat is above the operating temperature of the hold willtake a long time to cool down and will lose quality as aresult.

The terms of contract between the provider of thefrozen products and the recipient sometimes specifythe maximum temperature at which the productsshould be stored and delivered to the vessel – amaximum temperature of -10oC would be typical forfrozen tuna delivered from a tuna fishing vessel. Even ifthere is no specific requirement for the cargo’stemperature on delivery to the vessel, the master mayrefuse to accept a product if he considers thetemperature too high and the product at risk of damageduring stowage and carriage.

The deck officer should ensure that sufficientmeasurements are taken to provide an adequatesummary of the temperature cargo, and that themeasurements are accurately recorded. Guidelines fortemperature measurement are given in the Appendix atthe end of this article.

During loading, supervising officers should note anysoftening of the flesh of fish during transfer to thevessel – this can be gauged by pressing the surface ofthe fish with a thumb nail or the point of a temperatureprobe. Even when the temperature measured at thecore of a fish is low, the flesh on the outside can be softenough to be damaged by the pressure of a stackwithin the hold.

Condition of the material

It is not easy to assess the intrinsic quality of frozenproducts by visual examination, but, with experience,one can get some indication of pre-freezing quality fromthe appearance of the eyes and skin in the case ofwhole fish, from the colour of the shell in the case ofshell-on crustacean shellfish, and from the colour of theskin in the case of cephalopods. Of course, theseindications of quality will not be visible in packagedproducts unless some of the cartons are opened.Whenever possible, photographs should be taken ofany defects.

Visual indication of spoilage inindividually frozen fish

The inspecting officer should examine frozen fishindividually for signs of spoilage before freezing. Thetable below summarises the difference in appearancebetween good quality and stale fish.

nature and integrity of any strapping should be noted.

Wrapping, which may or may not be supplemented byfurther packaging in a carton, is intended to preventcontamination and dehydration. Wrapping is onlyeffective in protecting against dehydration if it is sealedor is closely applied to the product. The record shouldinclude details of the type and condition of anywrapping.

The officer should note any staining of cartons andouter wrappings, including the character and nature ofthe stain – lubricating oil, fuel oil, water, fish juices, forexample. Oils tend to be dark in colour and leave thewrappings soft, even when frozen; fish-juice stains areyellowish or reddish. The officer should note if thestaining is extensive, covering all or most of thecontainer or wrappings, or localised. When stains arelocalised, note whether they are predominantly oncorners or edges of packages or on the sides.

Good quality fish Stale fish

Colours bright, demarcated degraded and dull

Eyes clear or slightly cloudy; yellowish or reddish;flat to the head or even sunken or missingprojecting slightly

Skin clean – no discoloured abraded and covered withslime or coating with yellowish slime

or blood-stained brine;head region of tuna takeson a diffuse pinkish hue

Tuna spoiled prior tofreezing – note sunken,discoloured eyes, dullcolours, pinkishdiscolouration of head,loss of skin and dirty,bloodstained slime

Nature and integrity of packaging andwrapping

Packaging is intended to protect the product fromphysical damage. The inspecting officer should recordany damage to outer wrappings, particularly if thedamage has caused exposure of the contents.Sometimes the packaging includes strapping,particularly where a carton contains individuallywrapped, heavy products like blocks of fillets. The

Damage to outer carton, though wrapping and contents look unharmed

Blemishes, stains and contamination ofthe product

When the surface of the product is visible, it should beinspected for blemishes and contamination. Blemishesinclude surface damage to whole fish like abrasionsand tears to the skin or splits in the flesh, and surfacedamage to blocks such as patches of freezer burn. Anattempt should be made to assess the proportion of theconsignment affected.

It is important to record an unusual discolouration orstaining, and if possible the nature of the defect, forexample, blood or bloody brine (particularly on brine-frozen tuna), oil, and chemicals. The product shouldalso be examined for contamination by dust, organicmatter such as fish offal or vegetable debris, and anyother foreign matter.

In all cases of blemishes or contamination, theinspecting officer should note the extent of the damageand estimate the proportion of the consignmentaffected.

Signs of thawing or partial thawing

Sometimes claims are made against shipowners on thebasis that a cargo had thawed or partially thawedduring the voyage, and had then frozen again to thestipulated carriage temperature. It is thereforeimportant to check that a potential cargo does not showsigns that it had thawed and refrozen before it had beenpresented for shipment. Such thawing or near thawingis often indicated by distortion of product shape andrelease of liquids from the product.

usually on the dorsal surface at the base of the dorsalfin. Any other splitting should be noted by the officer.

Any distortions other than slight flattening or thepresence of minor depressions suggest that theproduct has warmed up, softened, and refrozen in thedistorted shape. The officer should note the nature andextent of any distortions.

Blocks of fish should reflect the sharp angles andregular, geometrical shape of the tray or former in whichthey were frozen. Blocks of fish which have thawedwhile stored on pallets or in stacks show signs ofslumping, bending, or compression and material isoften squeezed into spaces between blocks. Restraintssuch as strappings and the framing of pallets and shelf-supports cause indentations in the blocks of fish. Again,the inspecting officer should note the nature and extentof distortions.

Release of liquid

Fish release liquid as they thaw. The cargo officersshould check for pools of liquid collecting withinwrappings, and for signs that liquid has been squeezedfrom the blocks and has refrozen on the sides of thestack or on shelves and pallets. Staining of cartons issometimes an indication that the contents havethawed and released liquid.

Oil-stained cartons

Distortion

Distortion of whole or blocks of fish indicates that thematerial has thawed or partially thawed since freezing,or was distorted during the freezing process.

Individually frozen whole fish often have slight pressuremarks formed during the freezing process. These minordistortions must be allowed for during examination offrozen products. The nature of the marks depends onthe freezing process. For example, fish frozen in traysare slightly flattened or have indentations on one sidewhere they have lain on the trays during freezing. Brinefrozen fish tend to float in the brine tanks and arerestrained below the level of the brine by a grating. As aresult, the fish may have slightly flattened sides wherethey have been compressed, or shallow cylindrical-shaped depressions where fish lay across each otheras they froze. Sometimes the pressure on tuna duringbrine freezing results in splitting of the skin and flesh,

Transfer, stowage and carriageTemperature control during loading

It is very important for maintaining quality that frozenfishery products be held at low temperatures at alltimes. Although it is inevitable that the product’stemperature will rise during loading into the hold, theloading operations must be conducted so as to keepthis rise to a minimum. The product’s quality suffers notonly due to the immediate rise in temperature asmaterial is stowed in the hold, but also because of thetime taken to bring the product back down to therequired temperature after stowage.

Carton has been stained by fish juices when the block partially thawed

As far as possible, the cargo should be loaded at, orbelow, the required temperature of carriage – typicallyaround -18oC. Officers and crew should attempt tominimise warming of the cargo while it is being loadedand stowed in the holds, preferably so that thetemperature of the cargo is not above -10oC by thetime it is stowed. Although the ship’s crew may havelittle control over loading operations, the master shouldco-operate with the ship’s agent, and particularly withthe stevedoring company, to ensure that good practicesare adopted during loading and stowing.

Good practices during loading

● Ensure that delivery to the ship’s side is matched toloading onto the vessel to reduce the time thatproducts are waiting on the quay.

● Products should be delivered in insulated containersor lorries, or at least in covered vehicles.

● If the material must be unloaded onto the quay orheld on the deck of the reefer, it should be placed onpallets or on an insulating base, packed as tightly aspossible and covered with a tarpaulin or similarprotection against sun and wind.

● The cargo should be protected from exposure towind, rain and sun until it is about to be transferredto the vessel.

● In tropical climates, avoid loading for two or threehours either side of noon and consider loading thevessel at night.

Good practices during stowage

● Ensure that the hold is cooled to below the carriagetemperature before loading begins.

● During breaks in loading, cover holds or decks withat least the hatchcovers, even if the thermal coversare not put in place.

● Refrigeration to the holds should be turned onduring long breaks.

● Transfer cargo as rapidly as possible from the quayor discharging vessel to the hold.

● Once loaded, the cargo should be covered withtarpaulins.

● Where consistent with efficient loading, use only onehatch at a time to avoid through currents of air in thehold.

Maintaining low temperatures duringcarriage

There is usually an explicit or implicit requirement tohold the cargo below -18oC during carriage. The ship’s

refrigeration system must be capable of delivering air tothe holds at a temperature a few degrees below thetarget temperature to allow for heat leaks though theship’s structures. Cargo spaces in reefers are usuallycooled by re-circulating air systems, which are onlyeffective if the air can circulate freely through andaround the stow.

Most heat leaks into the cargo hold occur through thesides and bulkheads, and it is important to ensure thatthere is free circulation between the cargo and thestructures to the hold. Sides and bulkheads should befitted with vertical dunnage (without horizontal battenswhich could obstruct air flow) to keep the cargo awayfrom the structures. There should be an even gap of atleast 20cm between the top of the stowed cargo andthe lowest part of the deckhead.

Cartons should be stacked with gaps between themwhile stows of individually frozen fish will inevitably havespaces between the fish unless the fish are deformableand have been compressed.

The ship’s engineer should ensure that refrigerationequipment is well maintained and can achieve thedesign temperatures. Evaporator coils must bedefrosted as required to maintain the cooling capacity.Frequent need for defrosting is a sign of hightemperatures in the cargo and should be noted in theengine room log. In addition, the engine room logshould record temperatures at critical and meaningfulpositions in the refrigeration system – for example, theoutlet and return air streams in air cooling systems, andthe outlet and return fluid temperatures in pipe-cooledsystems.

It is vital to take and record temperature measurementsin the hold. How meaningful these measurements aredepends on the location of the temperature sensors.Material in the centre of the stow is the slowest to coolbecause the source of refrigeration is mainly around thesides of the stow. Refrigerated air percolates gapsbetween fish or between cartons and the cooling effectdepends very much on the existence of uninterruptedspaces. Sensors attached to the sides or bulkheads ofthe hold are exposed to cold air circulating through thedunnage against the sides or bulkheads and thereforetend to indicate temperatures lower than the bulk of thecargo. Sensors should be attached to posts or otherstructural members running through the hold, wherethey are more likely to reflect the temperature of thebulk of the cargo accurately.

Protecting the cargo fromcontamination

Every effort must be made to protect the cargo fromcontamination. Good shipboard practices will prevent

direct contamination by sea water, bilge water, fuel oiland the like, but it is important to be aware that fisheryproducts are rapidly tainted by odours picked up fromthe ambient air. This is a vital consideration when usingair-cooled refrigeration systems – the air must notbecome polluted by odiferous materials such as fuel oil,paints or chemicals used on the ship. A simpleguideline is that if the air circulating through the holdhas an odour, then that odour will be picked up by thefish products.

Unloading

When a cargo is unloaded from the ship, similarprecautions should be taken to those recommendedduring loading to minimise warming. Unloading shouldbe completed as quickly as possible and the cargoshould be protected from wind, rain and hightemperatures.

DocumentationThe importance of documents

Documents are fundamentally important in theinvestigation of any claim involving damage to cargo.They will be examined by the technical surveyors, andmay be used as evidence in any subsequent legalproceedings. The following documents are likely to beimportant in the event of a claim.

● Ship’s log.

● Bill of lading.

● Mate’s receipts and attached record of theinspection of the cargo prior to and during loading.

● Deck log of loading and unloading.

● Stowage plan.

● Engine room log.

● Any documentation arising from disputes duringunloading and/or receipt of cargo.

In addition, photographs and video recordings canprovide important evidence in support of statements inthe logs and inspection reports.

Mate’s receipts

The mate’s receipts should include the record of thepre-shipment inspection (see previous section). Thisrecord should detail all observations on the cargo’scondition at time of receipt, including results of at leasta visual inspection of each part of the consignment.Records should also include temperaturemeasurements, taken at sufficiently frequent intervals toprovide a fair indication of the average temperature ofthe cargo.

Any observations which indicate that cargotemperature is high, or that cargo was delivered in adamaged or deteriorated condition, should besupported as far as possible by further evidence. Thisevidence might include photographs taken during pre-shipment inspection or results of reports by cargosurveyors.

The mate’s receipt should include any information onthe nature of the consignment supplementary to the billof lading, as well as details of any labels.

Deck log for loading

LoadingMany charterparty agreements specify a minimum rateof transhipment or loading. To demonstrate compliancewith this, and to provide evidence in case of claimsconcerning damage to the cargo during loading, thetiming and sequence of events during loading shouldbe noted in the deck log. At minimum, the log recordshould include the following:

● Time alongside.

● Where cargo was loaded from – quay, lighter, fishingvessel.

● Times of opening and closing of hatches.

● Arrival and departure of stevedores onboard.

● Times when the refrigeration system was turned onand off.

● Start and finish of cargo stowage.

● Any breaks in loading.

● Weather conditions (sun, wind, rain, ambienttemperature).

● Any unusual or irregular events which might affectthe condition of the cargo during stowage orsubsequent carriage.

Deck log for unloading

UnloadingNormally, unloading may be the responsibility of thereceiver, and the master of the vessel could considerthat his responsibility for the cargo is over. However, thedeck log should continue to record conditionsduring discharge, logging similar information as listedabove for loading.

Stowage plan

A stowage plan should be drawn up for all cargoes – anaccurate plan is a central piece of evidence in anydamage claims arising against the vessel. The stowageplan should indicate the location of each

consignment and part of consignment and shouldinclude the following information:

● Number of units (pallets, cartons or blocks) in eachlocation.

● Gross and net weight.

● Origin of each part.

● The corresponding bill of lading.

Engine room log

The engine room log is one of the most importantdocuments, since it contributes evidence about thetemperature of the ship’s cargo during stowage andcarriage. The log should document at least thefollowing:

● The locations of temperature sensors in the holds.

● Temperatures at the sensors in the holds.

● Times when compressors were turned on and off.

● In air-cooled systems, the temperatures in the airstreams entering and leaving the holds andcompartments.

● In pipe cooled systems, the temperatures ofrefrigerant to and from the cooling pipes.

Actions in case of disputeAction by the master of the vessel

The master must load the cargo in apparent good orderand condition and act to maintain it in this state. Thissection describes actions to be taken when a potentialproblem is identified.

In the event of any concern or dispute over thecondition of the cargo while loading or unloading, themaster of the vessel should contact his owners orcharterers or his P&I correspondent. Best practicewould indicate that loading or unloading should ceaseuntil instructions have been received, although this maynot always be possible.

As soon as any question is raised over the condition ofthe cargo, the ship’s master should begin to documentthe events surrounding the discovery of defectivematerial, and the nature and possible extent of thealleged defects.

If possible, loading or unloading of the vessel should behalted and the hatches closed until a cargo surveyor ispresent. Ideally, cargo should be inspected andsampled while still in the hold, or even duringdischarge, allowing the surveyor to determine if thenature and extent of the damage is in any way related tothe position in the hold.

Once the cargo has been discharged into store, relatingdamage to location in the hold is obviously moredifficult, or impossible, unless the cargo is adequatelylabelled. Therefore, if loading or unloading mustcontinue, the master should ensure that each cargo unitis labelled with the hatch number and deck as well aslocation within the hatch and deck, as it leaves the hold.The deck log should also record the destination of thematerial and the agent responsible for handling it.

Records

The master should ensure that all records anddocuments relevant to the dispute are secure, and thatthey are only made available to parties representing theship’s interests.

Services of surveyors

When a problem is identified during loading orunloading – for example, if the temperature of thematerial is too high – loading or unloading should ceaseuntil the cargo has been inspected by a specialistsurveyor.

If the dispute concerns the quality of the product, it willprobably be necessary to call in at least onespecialist surveyor to examine the cargo, establish itscurrent quality and determine the nature and cause ofany defects.

If it is suspected that defects result from maritimecauses – for example, physical damage frommovement of cargo, or from contamination with seawater, fuel oil or bilge water – an expert in shipoperations should be called in. However, if the defectscould be attributed to the initial quality of the materialwhen loaded, or to the way the product was stowed andcarried on the vessel, a specialist surveyor wouldbe appropriate.

Many of the surveyors appointed by local shippingagents are general marine surveyors, often with aseagoing background; they are not necessarily skilled inthe evaluation of the quality of fish cargoes. Masters andagents are therefore advised to check the expertise andqualifications of surveyors carefully to ensure that theirtechnical background and experience are appropriatefor the particular job.

As a general rule, a single surveyor should not becommissioned for both a cargo survey and a survey ofvessel condition. Since the skills required for each typeof assessment are very different, it is unlikely that oneperson would have experience in both areas at the levelsof expertise required. A fish cargo surveyor should havea background in food science and the inspection of foodproducts, and, ideally, some experience in assessing thequality of frozen fishery products.

Official inspectors and samplingprocedures

Where official inspectors – for example, port healthofficers or veterinarians – are involved, the mastershould document the authority under which the officersvisited the vessel and the name and status of eachofficer.

The master is also advised to record the nature andamounts of any samples taken by representatives of theowners or by officials. Such records should include thelocation of the samples within the hatch or deck, theauthority under which the samples were taken and thedestination of the samples.

If part of the sample is given to the master, he shouldensure that it is fully labelled, and, if possible, that it issealed in a container under the impress of the persontaking the sample. The master should store the samplein a secure place, under conditions such that the qualityof the sample will not change.

If the cargo is in store, the surveyor should take intoaccount the manner of discharge and delivery to thestore, in case these operations could have affected thequality of the product or could in themselves beresponsible for any damage.

AppendixMeasuring the temperature of frozenfishery products

EquipmentThe most convenient thermometer for measuring thetemperature of frozen food products is a water resistantK-type thermometer with a digital display reading to0.1oC. Typically, these thermometers have a measuringrange down to minus 50oC and an accuracy of ±0.5oCin the range required when measuring temperature ofchilled or frozen foods. This accuracy is adequate forthe purposes described in these guidelines.

There are several types of probe available for plugginginto the instrument. The best all-round probe formeasuring temperatures of fishery products is a100mm long, 3-4mm diameter, stainless steelpenetration probe on a 1m lead. There are also stouter,hammer-in probes on the market for forcing into frozenfish (provided the temperature is not too low), but thesehave long response times. It is usually preferable to drillholes and use a thinner probe.

Measuring the temperature of frozen fishIt is not usually possible to push a probe into frozenproducts. Normal practice is to drill a hole, with anordinary engineer’s hand or power drill, of such adiameter that the probe fits tightly. The bottom of the

Thermometer and probe

Fig B. Inserting temperature probe into frozen fish or block of fish

hole should be at the thermal centre of the object that isat the position that will cool down or warm up mostslowly. The thermal centre is usually at the backbone inthe thickest part of a fish, or at the centre line of a blockof fillets. The hole should be around 100mm deep – thatis, sufficiently long to take the whole length of theprobe. This may mean that the hole must be drilled at anangle to the surface of a fish, or along the centre line ofa block from one of the smaller side faces.

Once the probe has been inserted, note the lowesttemperature reading given in the next 2-4 minutes.While the hole is drilled and the temperaturemeasurement taken, the product warms up, someasurements should be taken as quickly as possible,and preferably while the product is still in the hold.

most of probewithin product

probe fits snuglyin hole

point of probe atthermal centre

UK P&I CLUBIS MANAGEDBY THOMASMILLER

For further information please contact:Loss Prevention Department, Thomas Miller P&I LtdTel: +44 20 7204 2307. Fax +44 20 7283 6517Email: lossprevention.ukclub@thomasmiller.com

Measuring the temperature of products incartonsProducts in cartons may be delivered in regular stacksor in random loads. In a regular stack of cartons – forexample cartons on pallets – temperatures can bemeasured by inserting the probe between cartons. Thewarmest areas are the corner of the stack.

Temperature should be measured at diagonallyopposed top and bottom corners and in the centre of aface. Insert the whole length of the probe betweencartons, or between the flap and body of a carton, onthe mid-line. Insert the probe between verticallystacked cartons rather than horizontally adjacentcartons as the weight of the cartons above ensures agood thermal contact with the probe. Record theminimum reading. Pushing the probe between cartonswill result in some frictional heating, so five to tenminutes may be required to reach equilibrium. Whenmeasuring temperatures of cartons, it is useful to haveseveral probes, cover the stack to avoid heat loss, andallow 5 to 10 minutes before connecting the probes inturn to the thermometer.

Measuring temperature within a carton

When cartons are loosely stowed, it is necessary tomeasure the temperature within cartons. If the contentsare loose – IQF fillets, for example – the probe can beforced through the side of the carton into the product.

Thermal contact is poor in such cases – it may take 10minutes, or more, to reach thermal equilibrium. If thecartons contain blocks, it should be possible to insertthe probe between blocks to drill a hole in a blockthrough the side of the carton. The carton usually has tobe split to locate gaps between blocks and the centresof faces of blocks.

Calibration of the thermometer and probesInstruments are calibrated by their manufacturers, but itis possible to check thermometer/probe combinationsat 0oC on the vessel.

Finely crush some ice made from fresh or distilledwater, and pack it tightly in a vacuum flask or jar. Addcold water to fill the flask and insert the probe to its fulllength in the ice/water mixture in the centre of the flaskand leave the flask and probe for a while in a cool place– perhaps a refrigerator or chill room – before taking atemperature reading. Since a mixture of ice and freshwater at thermal equilibrium has a temperature of 0oC,any deviation of the probe/thermometer combinationfrom 0oC is the correction for that system.