CHAPTER No 4
CLEANING OF HOLDS – general considerations
When the discharge of a hold is completed, the Master must decide when, where and how the hold is to be cleaned.
This will mainly be a commercial decision made by the vessel’s operator, whether owner or charterer. Regardless of the previous cargo, all holds should be thoroughly cleaned by sweeping, scraping and high-pressure sea water washing to remove all previous cargo residues and any loose scale or paint, paying particular attention to any that may be trapped behind beams, ledges, pipe guards, or other fittings in the holds.
When on time charter the Master should ask the charterers when they require by way of hold cleaning.
All bulk carrier officers should have clear guidance and instructions available onboard their ship. There should be guidance on:
• preparation of holds,
• carriage requirements of bulk cargo,
• safety aspects of bulk cargo carriage etc (liquefaction, heating, hazardous gases, oxygen depletion, entry into enclosed spaces)
Checks should include the following:
1. Cargo contamination problems.
Whatever the previous cargo, all holds should be swept clean, and loose scale and rust removed.
When reloading the same cargo commodity, there is a tendency to leave the holds unswept.
In general terms, this is not good practice since the residual cargo can hide damage to the hold or tank top.
Traces of previous cargoes, such as sulphur, sulphur traces in coal cargoes and some fertilizer cargoes may corrode bare steel plate.
It is recommended that holds are swept clean after every cargo and the residues removed or, if reloading the same cargo type, placed to one side so that a tank top and hold inspection can be carried out. Large amounts of cargo remaining onboard may not only cause outturn problems, but hide damage to the tank top plate.
The level of cleanliness of the hold required will vary from port to port, and shipper to shipper.
As a general rule, if nothing specific is stated, a double sweep, with a saltwater wash followed by freshwater wash, is a sensible option.
In order to avoid delays or off hire of the ship, hold cleaning requires proper planning.
2. Problems stemming from previous cargo.
The holds will be declared unfit for loading if any
(1) residue found of the previous cargo,
(2) debris found,
(4) dunnage residue,
(5) need for repair or hot work is found.
3. Cargo stain.
Cargo stains are not acceptable if they rub off and risk contaminating the next cargo.
Surveyors give coal and petcoke stains particular attention because these can blister and peel the paint work if the hold starts to sweat.
4. Rust, rust scale and paint flaking.
All areas affected by rust and flaking paint will be checked by the surveyor.
The holds will be declared unfit if loose rust or paint flaking is found.
“Loose scale” It is important to differentiate such scale from oxidation rust ( i.e. light atmospheric rusting ).
Loose scale will break away when struck with a fist or when light pressure is applied with a knife blade or scraper under the edge of the scale.
“Oxidation rust” will typically form on bare metal surfaces but will not flake off when struck or when light pressure from a knife is applied.
Generally, the presence of hard-adhering scale within a hold is acceptable in a grain clean hold.
The scale should not fall during the voyage or during normal cargo operations.
5. Unsanitary conditions
If a hold is found to contain animal filth, bird droppings, faces or sewage, it will be rejected.
There must be no evidence of rats or rat droppings.
If this is suspected, specialist assistance and probably fumigation will be required by the local authorities who should be notified accordingly.
Holds must be thoroughly checked and any unsanitary conditions treated appropriately.
If any sewage is found, it must be identified and the source found.
It should be stored onboard properly before being discharged ashore.
All holds must be dry. If the holds contain water or leaking water, the vessel will be declared unfit. Bilges and bilge wells must be dry.
All grain storage areas must be odour-free. This includes odour from paint and cleaning chemicals.
Holds will be declared unfit to load grain if three or more insects, dead or alive, are found in one hold.
The holds will also be declared unfit if larvae or unhatched insect eggs are found. Under the Australian Quarantine Inspection Service rules, there must be no bugs: any found will result in the hold failing the cleanliness survey.
Special attention must be given to exposed areas such as under hatch covers, hatch coamings, access ways and bottom areas of the bulkheads, slopes and tank tops.
All adjacent spaces to the holds, (for example, mast houses and storage spaces) should be inspected to ensure that they are also infestation-free.
WHAT CLEANING IS NEEDED
In the dry bulk trades, there are essentially (5) five grades of hold cleanliness:
is the most stringent, requiring the holds to have 100% intact paint coatings on all surfaces, including the tank top, all ladder rungs and undersides of hatches.
The standard of hospital clean is a requirement for certain cargoes, for example kaolin/china clay, mineral sands including zircon, barytes, rutile sand, ilmenite, fluorspar, chrome ore, soda ash, rice in bulk, and high grades of wood pulp.
Generally, these high standards of cleanliness will only be met by vessels trading exclusively with such cargoes.
It will rarely be required in the tramp trades.
The most common cleanliness requirement for bulk carriers is that of grain clean.
The usual instructions a master of a tramping conventional bulk carrier will receive, particularly if his ship is unfixed for next employment, is clean to Grain clean on completion of discharge.
This guideline is aimed at the majority of bulk carriers engaged in the carriage of ‘usual’ bulk cargoes in conventional ships, which are cleaned to a grain clean standard.
(all grains, soya meal and soya products, alumina, sulphur, bulk cement, bauxite, concentrates, and bulk fertilizers).
The industry accepted definition of grain clean is provided by the National Cargo Bureau (NCB).
“Compartments are to be completely clean, dry, odour-free, and gas-free. All loose scale is to be removed.”
The definition is clear:
• All past cargo residues and any lashing materials are to be removed from the hold,
• Any loose paint or rust scale must be removed,
• If it is necessary to wash the hold, as it generally will be, the holds must be dried after washing,
• The hold must be well ventilated to ensure that it is odour-free and gas-free,
means that the holds are swept clean, with no residues of the previous cargo, and washed down (or not, depending on charterer’s requirements), that is, cleaned sufficiently for taking cargoes similar to or compatible with the previous shipment.
means that all previous cargo that can be removed with a ‘Bobcat’ or a rough sweep and clean with shovels by the stevedores or crew. The master should clarify what standard is expected.
Load on top
means exactly what it says – the cargo is loaded on top of existing cargo residues.
Usually, this means ‘grab cleaned’.
This standard will commonly be required where a ship is trading continuously with the same commodity and grade of that commodity.
This will typically occur when a ship is employed under a Contract of Affreightment to carry, for example, a single grade of coal over a period.
With such a trade, there is no commercial need for holds to be cleaned between successive cargoes, and each cargo is simply loaded on top of any remaining residues from the previous cargo.
With load on top, guidance may be necessary for the master on any cleaning requirements, including the use of bulldozers and cleaning gangs.
SYSTEM FOR REMOVAL OF WATER FROM HOLDS
Bulk carriers are usually provided with a bilge suction system, which uses a pump or an eductor in the engine room to extract water from holds.
The water is drawn through the bilge line, past a non-return valve to the engine room and discharged overboard.
Such a bilge system is usually operated with the same pump or educator as is used for stripping ballast. Such system cannot be used to wash large particles of cargo out of the holds as cargo residues will clog the suctions, non-return valves and bilge lines.
Nor can it be used to remove cargoes which may set solid in the bilge lines.
The holds must be swept very thoroughly and the cargo residues must be lifted out of them before the holds are washed.
An alternative arrangement, found in some bulk carriers of all sizes, is the fitting of port and starboard bilge eductors or ejectors – a form of pump – above the bilge wells in each hold. Water is usually taken from the deck fire / wash line to drive the educator and the combined bilge and drive water is discharged through a pipe led directly overboard at deck level.
Provided that the diameter of the discharge line is sufficient the system can discharge lumps (σβωλους) of cargo the size of apples.
As a result, thorough sweeping and removal of residues is much less necessary.
Yet another variation is for bulkers to have a single educator in each hold, specifically for hold cleaning in addition to conventional bilge lines and suctions.
Flooding of the hold by water from the educator system is prevented by a non-return valve in the bilge suction line.
A none-return valve is also fitted in the discharge line if the discharge opening is situated below the water line.
Some bulk carriers have been built without non-return valves in the eductor’s bilge suction lines because, if fitted, non-return valves are frequently damaged by lumps of cargo which are sucked through then the powerful suction of the educator.
In this case when the educator is stopped the water remaining in the discharge line (the back-flash) will return to the bilge well.
The bilge wells are amply (επαρκής) sized, provided with high level alarms and can be emptied by a “mucking pump”.
Ships equipped with portable eductors sludge pumps will use them for hold washing “when the” quantity of bulky or difficult residues to be removed justifies the time and effort required to lift the eductor into and out of hold.
From what is written above it is obvious that, when preparing to clean holds it is necessary to take account of which type of water removal system is installed.
The first steps in the cleaning process should be take whilst the cargo is being discharged.
Cleaning at high levels.
When discharging cargoes such as grain, it is often worthwhile to send crew members into the holds to clean steelwork at high levels during interruptions in discharging, Whilst standing on the cargo during early stages of the discharge they can, using damped (υγρες) brooms or mops, reach places such as underdeck beams that later become inaccessible. Such work must always be carefully supervised to ensure the safety of crew members and is, of course, subject to safe access and local regulations.
Need for complete discharge.
Cleaning the holds will be much more difficult if quantities of cargo sweeping have been left in the hold, particularly if the cargo is not soluble in water, so the ship’s officers will do all that they can to compel or persuade the stevedores and trimmers to discharge all the sweepings.
If a bilge cover plate has been displaced and cargo has filled bilge, the trimmers will be unwilling to remove it. If they cannot be induced to do so it will be worthwhile to send the crew to get all the cargo out of the bilge, before the finish of discharge, so that the contents of the bilge can be discharged along with the rest of the cargo.
Stevedores are often willing, if asked, to return to a hold where discharge has been completed, to remove sweepings gathered by the crew.
They may even be prepared to leave a grab resting in the hold for a while into which sweepings can be shoveled.
On a gearless bulker such help is very welcomes.
Before closing the hatches.
On completion of discharge the hatch coaming top, the compression bars, the coaming drains, and the hatch cover seals must be clean and free of residues, particularly if the hatches cannot be opened during the ballast passage.
Hatches cannot be opened at sea when conditions are rough, because hatch panels may be disclosure or even lost overboard. For this reason some companies forbid the opening of hatches at sea. In the discharging berth this cleaning can be done with a compressed air hose for with hand held brushes.. During these cleaning operations it is essential that ship’s staff wear suitable protective equipment to prevent eye injuries or inhalation of the cargo dust.
All hatch corner drains, including the non-return valves, should be proved clean and clear.
The blanking caps on the hatch corner drains used to ensure hold air tightness should be attached by a chain to the drain.
These blanking caps or plugs are provided if the drains do not have an approved automatic means of preventing water ingress into the hold.
WASHING OF HATCH COVERS AND COAMINGS
At some point before loading the next cargo the hatch cover tops, bottoms and cross joints, along with the inner sides of the coaming should be washed to ensure that no residues can contaminate the next cargo. This is most easily done from on deck with the hatches partly or fully open and should, therefore, be done in sheltered or calm waters.
If time permits, when the cargo has been discharged from respective hatches, all inner hatch coamings should be teepol washed and fresh water rinsed with the fresh water high-pressure gun, because it is more convenient to wash this area in port rather than at sea.
If permitted by the port authority, all hatch tops should be dock water washed, ensuring that cargo remains are retained onboard and not washed into the dock.
The fitting of plugs to all deck scuppers should help prevent any pollution claims alongside.
It is essential that permission is given by the port authority for this washing operation.
Under normal circumstances, when it rains during cargo operations, discolored water from the decks will flow into the dock and this is normally accepted by the port authority.
The washing of cargo debris into the dock is not acceptable.
In some loading ports, where helicopter operations (See MARPOL exceptions below) are used for embarking and disembarking the pilot, it is a normal requirement of the port to wash down the helicopter area and at least one hatch length either side of the helicopter area, ensuring that cargo debris is not washed into the dock.
Even if the holds are not to be rinsed with fresh water it is recommended that hatch covers, coamings and underwater areas are rinsed to ensure that any condensation which drips onto the next cargo will be free of salt.
When hold ventilators are set into the hatch covers they must be thoroughly cleaned.
In some ports hose or ultrasound tests may be required to prove weather-tight integrity of the holds prior to loading cargo.
It is in the ship’s interest to ensure all traces of hatch tape are removed to prevent creating additional suspicion
WATER – TIGHTNESS TEST
he surveyor may be asked to test the hatch covers for water-tightness by any of the following three methods:
Carried out with a minimum 12 mm diameter nozzle hose capable of delivering a jet of water to a free height of 10 m.
The jet should be directed towards the watertight joints on a closed hatch cover from 1.5 m to look for any signs of leakage
Using an ultrasonic signal generator in the cargo hold, the strength of signal (the Open Hatch Value – OHV) is measured with hatch covers open or through hatch access.
This is then compared with readings taken with hatch covers closed (the Closed Hatch Value – CHV). Readings close to OHV indicate leakage and should be investigated.
A difference of less than 10% between OHV and CHV is acceptable.
Chalk is applied on all compression bars. The hatch covers are then closed to see if there is a chalk imprint on the rubber gasket. If there is no chalk imprint, the gasket has not compressed and maintenance is required.
PREPARATION FOR HOLD CLEANING
To prevent cargo debris from the main deck being walked into the accommodation and tramped into freshly washed cargo holds, wash down the main decks and accommodation block as soon as possible after clearing the port of discharge, mindful of pollution from the cargo remains.
Prior to the commencement of the hold-cleaning, a quick safety pre-brief meeting should take place, which should include all the personnel who will be involved in the hold cleaning.
During the pre-brief the hold-cleaning schedule should be discussed and the equipment and chemicals to be used must be fully explained and the safety data sheets understood by all involved.
Basic safety routines should be established and the wearing of suitable attire throughout the hold cleaning must be of paramount importance.
The wearing of oilskins, safety shoes/safety sea boots, eye protection, hand protection and safety helmets complete with a chin strap, should be made mandatory during the hold cleaning process.
The wearing of high visibility waistcoats will help to improve safety in the hold.
The ‘permit to work’ should be completed on a daily basis, as this will help reduce the risk of accidents.
HOLD CLEANING EQUIPMENT
Hold cleaning is time-consuming. To minimize time spent on the task, it is essential that the ship is suitably equipped.
Equipment should include good-quality brushes and brooms, suitable scrapers, ‘man-helps’, receptacles for removal of residues from the holds, heavy-duty hoses and nozzles, enhanced delivery systems such as the Stromme Combi-Jet or Maxi-Gun, spray foam equipment, paint, protective and cleaning chemicals, and where appropriate, high-level access equipment such as a scaffold tower or cherry-pickers.
This requires a minimum pressure flow from the general service pumps and the air compressor, with the dimensions of the deck pipes affecting the process.
Pressure drops should be calculated and simple and cost-effective improvements such as increasing the diameter of water and compressed air couplings should be evaluated.
High-pressure cleaners of 350 to 500 bar should be part of the standard equipment onboard any bulk carrier.
These are useful if not essential to clean the holds properly.
Hot-water cleaners although not commonly used are reported to make the wash-down operation more effective and may obviate the need to use chemicals.
GRAIN CLEANING “EQUIPMENT” CHECKLIST
• A fully working high-pressure hold cleaning gun (Toby gun or Semjet or similar) – complete with sufficient deck wash down hoses and air-lines all in good condition. Fire hoses must not be used as wash down hoses as they are part of the ships safety equipment.
• Ship has a fully operational salvage pump (Wilden pump) and approved spares.
• Sufficient fresh water to complete a high-pressure fresh water rinse of all the holds. It will be more cost effective to over-supply fresh water for hold cleaning than the ship to run out during the hold cleaning. (A typical 100,000dwt bulker requires around 30 tons per hatch).
• 1 x portable pressurized fresh water gun, complete with extended handle and 30 meters of pressurized hose.
• 6 x long handle steel scrapers complete with handles.
• 3 x lightweight, strong, aluminum extension poles with capability to extend to approx 5 metres.
• 6 x long handled rubber squeegee complete with 1 metre rubber blades.
• 10 x heavy-duty bass brooms, c/w handles, suitable for hold cleaning.
• 6 x corn brooms c/w with handles.
• 6 x heavy-duty mops, c/w handles.
• 6 x spare mop heads suitable for above.
• 4 x galvanized, roller wringer, mop buckets.
• 6 x turks heads, round head 4 inch, c/w handles.
• 6 x small 6 inch wide, hand shovels, steel, suitable for digging out hold bilges.
• 3 x 25 meter length, lint free soogee cloth, width approx. 30cm.
• 1 x 50 meter length burlap, 1 meter wide.
• 10 x rolls of 50 meter length, 10cm wide, grey, industrial strength duct tape.
• 6 x 20 meter length, ‘yellow’ wash down hoses, duraline, 45mm dia complete with couplings suitable for ship’s fire main.
• 4 x plastic jet nozzles, suitable for above hoses.
• 4 x 50 meter lengths, transparent plastic, reinforced garden hose, complete with male and female plastic couplings to join each section.(for use with Kew gun).
• 2 x universal tap connectors for above reinforced transparent plastic garden hose.
• Sufficient hatch sealing tape to comply with operators instructions.
• 4 x 500 watt, portable lightweight halogen lights to illuminate hatches during cleaning. Each lamp to be complete with 50 meters of cable and have a waterproof plug fitted.
• 10 x spare halogen bulbs for above.
• 2 x 50 meter extension cables each complete with three waterproof outlet sockets and a waterproof plug.
• 5 x 20 liter drums concentrated teepol.
• Sufficient drums of de-greasing chemical wash suitable for use with sea water (e.g. Sea Shield detergent cleaner or equivalent).
Some first class operators / charterers of bulk carriers require their owned and chartered bulkers to be equipped with a minimum of one air / water Combi-gun and preferably a second Combi-gun and a Maxi-gun, the latter being a more powerful version of the Combi-gun.
They must also carry one Spray Foam Gun for applying chemicals to hold bulkheads and about 1000 liters (for Handy-sized and Panamax) of cleaning chemical such as Aquatuff (an environmentally friendly product supplied by Unitor) for use when water washing gives insufficiently good results.
Also required a mucking winch and sufficient long ladders, scrapers, mops, brooms and bamboo or aluminum “man-helps” (long poles) for knocking down cargo. About 500 to 1000 liters of chemical, will be required to clean a ship after a difficult cargo such as sticky coal.
The required quantity of chemicals should always be maintained aboard ship and rapid re-supply can be made from depos in many parts of the world.
Even with this equipment properly used, a perfectly clean hold after the dirtiest cargo cannot be guaranteed, but operators / charterers consider that with the assistance of this equipment they have on many occasions been able to avoid having the holds rejected.
A single instance of this sort, they believe, is sufficient to recover the cost of the equipment.
Digital cameras are used on board to report on the condition of the holds and ships personnel are sent on training courses in hold cleaning skills.
SWEEPING OF HOLDS
Sweeping of holds is normally the first step in the hold cleaning process. On occasion it will be the only step as there are at least four (4) situations in which hold washing is not required or cannot be carried out.
Sweeping of holds when washing is not permitted.
If a ship required too backload a bulk cargo in the same port as that in which she discharges, and if hold washing in the port is not permitted, it will be necessary to achieve the required standard of cleanliness by sweeping and then lifting the sweepings out of the hold to stowed on deck until such time as they can be landed or disposed of legally at sea.
This is work which the crew will be expected to do it if time permits, so the chief mate will make every effort to ensure that the stevedores complete a good discharge and leave the minimum of sweepings in the hold. Shore labor must be employed for cleaning if there is insufficient time for the crew to complete the work before loading is due to commence.
The quality of the required cleaning will depend upon the intended cargo and the danger of contamination, but as a general rule it is unreasonable to expect a very high standard cleaning if washing is not permitted.
Sweeping of holds when washing is not necessary.
Washing will probably not be required following a clean cargo such as steel coils or steel slabs. It will be sufficient to sweep up any debris and remove it from the hold.
Sweeping of holds in freezing conditions.
Washing cannot be undertaken in freezing conditions. When the temperature is below freezing and the water is brackish, as it is in the Baltic and approaches, washing water will freeze on bulkheads and coamings. In these circumstances holds can only be scraped and swept clean, with all residues including ice having to be lifted from the hold.
If early warning is given, massive Fan Heaters can be hired in some Baltic ports to dry out holds if the ship arrives with a coating of ice in the holds to load a sensitive cargo such as chemical fertilizer.
The heaters are normally connected to a shore power supply. A mobile crane will be needed to place the heaters in the hold if the ship does not possess her own cranes and there is no permanent crane at the loading berth.
Sweeping of holds when water will cause damage.
Certain exceptional cargo residues must not be washed at all.
It is reported for example that Copper Concetrate if washed will form “concrete” laver on the hold sides which can only be removed with abrasive discs on disk sander grinders.
This cargo must be cleaned by thorough blowing with compressed air and by sweeping.
Sweeping of holds in preparation for washing.
Holds should be swept and the sweepings removed whenever the stevedores will accept and discharge the sweepings before the vessel sails from the discharge port.
In addition the holds should be swept before washing, except when the residues are soluble or when fixed or portable hold eductors ( a form of pump) which can remove the residues are available. (can discharge lumps)
DISPOSAL OF CARGO RESIDUES – CATEGORY 4 – AND ASSOCIATED WASTE
Nature of cargo residues.
The MARPOL regulations and national and local regulations govern the disposal of cargo residues and determine whether they are released at sea or landed in port.
Soluble cargoes such as salt will normally present no problems for hold washing, and sweepings of granular (κοκκώδη) cargoes like mineral sand or concetrates can usually be washed away without difficulty.
Where cargoes come in larger lumps, like quartz (χαλαζίας), for example it is particularly important to ensure a complete discharge of the sweepings since remnants cannot be drained from the holds and will have to be lifted out by the crew.
Residues such as cement which could set hard within the bilge system, cannot be washed through that system but must be discharged directly overboard from the holds by submersible pump, or dedicated hold educator system using copious (αφθονο) quantities of water.
Alternatives methods of disposal.
Most cargo residues are washed from holds, the washings being discharged into the water alongside the ship. When residues cannot be washed from holds they must be lifted from the holds for later disposal. A geared bulk carrier equipped with her own cranes will be able to use them if necessary to lift sweepings from the holds, provided that the ship is steady enough to permit the use of the ship’s gear. If the weather is rough or if the ship is gearless it will be necessary to use a mucking winch and davit fixed to the hatch coaming or access or trimming hatch, to raise sweepings from the hold. In most cases the use of the mucking winch will be the most convenient option.
Use of mucking winch.
A mucking winch and the seamen who use it can only handle small quantities of sweepings, for example a full bucket or 20 liter drum at a time. The container is filled in the hold and carried to a position below the mucking inch where is hooked on and raised to deck level. It is swung clear of the hatch coaming and landed on the deck where it is immediately (1) tipped over the ship’s side, or (2) is emptied on deck for later disposal, depending upon the nature of the sweepings and the location of the ship. Sweepings can be (3) tipped on deck in front of an open hydrant (pump) where the water from the hydrant can be used to wash them overboard. Inexperienced crew members must be reminded to tip or wash the sweepings over the lee side.
Sweepings left on deck.
If the sweepings have to remain on deck they present problems for the ship, since residues are liable to be blown about the ship by the wind and they may stain the deck and the ship’s side, For this reason they should where possible be (1) retained in the hold until such time as they can be tipped overboard. When this is not possible the sweepings should be stowed on (2) deck in drums. On larger vessels where the quantities involved are too great for the use of drums the sweepings are usually (3) stowed between hatches slightly dampened down and temporarily covered with old tarpaulins and pallets to prevent them from being around the ship. Lifting of sweepings from the hold is a labor intensive and potentially dirty process. It is always preferable for the ship to dispose of residues by washing and this method is adopted whenever possible.
Sweeping left in hold.
If it is not possible to remove sweepings from the hold before arrival at the loading port because of adverse weather or because of the weight and volume of the sweepings, they should be piled (σωρούς / στίβες) in an accessible part of the hold in drums or sacks if possible, ready for rapid removal upon arrival.
In the rare cases when this is done, it will be necessary to give owners or charterers maximum warning to ensure that facilities are ready on arrival and off-hire time and costs are minimized.
The normal method of cleaning holds is by washing with water drawn from the sea. This involves hosing down every part of each hold with a water jet whilst the water is drained from the hold the eductors or bilge pumps, and discharged overboard.
Three alternative methods of hosing down the holds exist – using (1) handheld hoses, (2) water cannon, (3) a permanent installation.
(1) Handheld hoses.
The hosing may be done by Handheld operated by a team of two or three seamen.
One will be on deck to operate the control valve where the hose connected to the deck service line or fire main and will oversee operations, whilst others will drag the hose around the hold and direct the jet at each part of the compartment in turn.
On larger vessels it is important to use at least two men to handle the hose, since one will be unable to control the hose at full pressure and will do poor job, either because the hose has been badly directed or because the pressure has been reduced.
Aboard a small ship with holds which are not particularly dirty, a handheld hose is often the quickest and best method of completing the job.
Handled hoses are less satisfactory in larger ships – it is difficult to achieve good cleaning in the more remote parts of the hold and the method requires a lot of time and labor. .
(2) Water cannon.
An alternative to using a handheld hose is to have the hose led to a high pressure sea-water cannon, such as Combi- Gun, or the more powerful Maxi-Gun, on a tripod placed in the hold. These water cannon use compressed air from the ship’s deck line to inject greater pressure into water from the fire main.
This system, more likely to be used on larger bulk carriers, provides a more powerful jet of water than can be achieved with a handheld hose and results in better cleaning of high extremities of the holds. The system takes longer to move from place to place and requires as much labor as does the handheld hose.
The washing sequence adopted when washing with handheld hoses or water cannon starts at the top of the hold and works towards the bottom.
First, hatch covers are washed on all sides, as far as possible.
Compression bars and rubbers may need scrubbing to remove cargo which is sticking to them.
Next, the coamings, underdeck areas and hold sides are washed, paying particular attention to non-vertical surfaces such as hopper angles.
Pipe guards and brackets. Finally, the tank top is washed and the bilges are flushed.
Some ships are use two washing teams, one on deck to wash hatch covers and coamings with a handheld whilst the other team uses the water cannon to wash within the holds.
Within the holds a systematic procedure for washing is necessary to ensure that all parts and fittings are washed from at least two positions. Every frame and beam, for example, should be washed with a water jet first from one side and then from the other: this can be achieved by going around the hold twice,
first clockwise then anti-clockwise. It is necessary to be absolutely methodical in this work, to ensure that every centimeter of the hold is thoroughly washed.
Where it is impossible to direct a jet of water directly on to one side of a beam from any position on the tank top the beam must be hosed from a position on the hold access ladder, or “splashback” must be used to ensure that washing is complete.
Wet sticky coal can be very difficult to remove when compacted behind steel casings protecting ballast and air pipes.
It can be dislodged by water cannon and / or bearing the casing with heavy hammers.
(3) Permanent installation:
The third option for washing the holds is to use a permanent washing installation with water guns installed under the deck-head in the hold. Aboard a mini-bulker the hold would be equipped with one water gun at each end. Each gun is wound down into the hold from a recess in the deck-head. Water at high pressure is provided by direct line from the engine room. If the full washing program is selected, the gun will then automatically move through a full washing sequence with the hose directed first upwards to the deck-head, then more or less horizontally on to the bulkheads and finally downwards towards the tank top. Alternative washing programs can be selected. A bottom wash is a wash of the tank top only. The program is designed to wash towards the after end of the hold, where the bilge suctions are located.
Water must not be allowed to stand:
All the above systems of washing depend upon the flow of water to wash any dirt and residues down the bulkheads and across the tank-top to the bilge suctions.
If the washing is to be effective, it is preferable that the water is pumped or educted from the holds continuously and that no pool of standing water is allowed to form on the tank-top,
Whilst in ballast the ship will normally have a good stern trim, causing the water to flow across the tank-top and thereby assisting the washing progress.
On some ships the washing is found to be most effective if the ship is listed 1 degree ° with ballast water if one bilge suction is blocked, the ship can be quickly listed the other way allowing the use of the other suction to pump out the water. This will permit access to the blocked suction to clear it.
An exception to the above procedures occurs when is necessary to wash holds in port because of lack of time, but the washings cannot be pumped overboard in port.
In these circumstances the washings can be left in the hold to be pumped out when the vessel reaches the open sea.
This procedure is often adopted with the ballast hold and can be followed with another hold, provided that is safe to do so.
It will be safe only provided that the water in the hold remains at low level, say, up to one meter, and provided that calculations show that the ship’s stability will remain adequate despite the reduction in metacentric height (GM) from the free surface of the water.
Fresh water rinse:
When holds are washed with sea water traces of salt remain on all the surfaces within the hold.
This is unacceptable to some grain surveyors and is liable such as steel products and woodpulp.
Salt traces will also encourage corrosion and are to be avoided if possible.
For these reasons holds should be rinsed with fresh water after to contaminate cargoes full washing. One method of achieving fresh water rinse is to load fresh water in a suitable ballast tank such as the forepeak or after-peak and then to pump the fresh water through the deck service line for use in hosing down the holds.
When using this method it is important that the crew members operating the hose understand that they are using fresh water from a limited supply and not the sea water which is normally runs through their hoses.
The water must be used efficiently and with care to provide a quick rinse of each compartment if all holds are to be properly washed with the available supply of water.
On a handy sized vessel, where the fire pump has a capacity of 200 tons / hour, 2- 3 minutes spent rinsing each hold with fresh water will use a total of 50 tons for the entire ship and should remove most of the salt from the structure.
Some ships routinely use much larger quantities of fresh water for final rinsing and consider that the expense is justified.
An alternative method of fresh water rinsing is to use a portable high pressure washing machine, This will use less fresh water, but will take much longer.
Fresh water has a cost in most ports, so, if sufficient water for hold rinsing cannot be generated abroad ship, care should be taken to ensure that the water for hold washing is obtained where is cheap or free, the best sources of supply being those few places where the ship floats in clean fresh water. When appropriate the receipt for fresh water should be clause ”Hold Washing – For Charterers Account”, as it is the accepted practice in some trades for charterers to pay for fresh water washing when required for cargo purposes.
The practice of the routine fresh water rinsing of holds is becoming more widespread as the benefits are more widely recognized.
Precautions when washing within port limits:
In most ports nowadays hold washing is prohibited since the port authorities do not want cargo residues discharged into their waters, regardless of whether or not the commodity in question is a harmful or offensive one. If there is doubt as to whether hold washings can be discharged in port, it is prudent to obtain written permission via the agent. A spoken assurance from a stevedore is no guarantee that the ship will not be penalized later.
Washing holds in port may be permitted when the washing water can be retained aboard, in the hold or cargo hold washing water tanks.
When hold washing is permitted at the berth and the washing water discharge is above the surface it is usually necessary to discharge the washings only on the offshore side of the ship to avoid flooding the jetty.
If hold washing is permitted within the port, arrangements must be made aboard ship to ensure that discharge of washing water can be stopped immediately if a pilot boat or other craft has reason to approach. This will ensure that accidental flooding of boat can be prevented.
Washing of holds at sea:
If holds are to be washed at sea with handheld hoses or water cannon, the process can be carried out most safely by leaving the hatch covers closed and passing the hose down the access hatch. Unfortunately this makes (1) manipulation of the hose more difficult and provides poorer (2) lighting. It also interferes with easy (3) communication between the members of the washing party. In these circumstances there are strong reasons for opening the hatches 1 meter, if no more.
Since the ship will be in ballast with a large freeboard, there is normally no realistic danger of foundering as a result of opening hatches.
The danger lies in the hatch covers suffering damage or becoming unshipped whilst they are unsecured, as a result of a ship working in a seaway.
Hatch covers should never be opened at sea, except in calm conditions, and the hatch panels when open must be well secured.
The ship’s procedures should ensure that the opening and closing of hatch covers at sea is properly supervised and only occurs when it is safe to do so. Securing hooks (safety hatches), provided for securing open hatch panels in port, are inadequate (ανεπαρκη) for use when at sea and should be supplementary by strong lashings.
If conditions start to become rough whilst hatches are open, the vessel must be hove – to or her course must be adjusted to provide a steady platform whilst the hatches are closed.
Permanent washing installations and butter-worth systems are designed to be used with the hatches closed. There is no problem in using them when the vessel is at sea.
Bulk cargoes classified as HARMFUL
Until further notice, wash water from cargo holds having previously contained solid bulk cargoes classified as HARMFUL to the marine environment (HME) may be discharged. outside special areas, provided that:
• based upon the information received from the relevant port authorities, the Master determines that there are no adequate reception facilities either at the receiving terminal or at the next port of call.
• the ship is en-route and as far as practicable from the nearest land, but not less than 12 miles.
• before washing, solid bulk cargo residue is removed, and bagged for discharge ashore, as far as practicable and holds are swept.
• filters are used in the bilge wells to collect any remaining solid particles and minimize the amount of solid residue discharged, and
• the discharge is recorded in the Garbage Record Book and the Flag State is notified using the Revised Consolidated Format for Reporting Alleged inadequacies of Port Reception
Facilities MEPC 1/Circ 469/Rev.2
MARPOL Annex V prohibits the discharge of almost any kind of garbage at sea.
It is therefore important that the crew is familiar with the current garbage disposal requirements and have clear understanding of the conditions permitting certain discharges IMO simplified overview of restrictions and discharge provisions may be used as quick reference guide for this purpose.
MARPOL provides certain exceptions for the discharge of cargo residues where the safety of the ship or its crew is threatened.
• If the residues of cargo on deck may interfere with the safe landing / take off of the helicopters used for pilot operations
• Ιf the dust/residual cargo blown from deck may impact the lookout functions of the watch-keepers
• if the ship’s crew are likely to sustain a chemical injury by contact with a cargo.
Recommendations for de-ballasting, sewage, cargo residues, incinerator ash, garbage.
Due to the difficulties of defending allegations of pollution in sea waters, vessels should implement suitable measures to minimize the possibility of fines being imposed, and the following recommendations should be considered:
• As far as is safe and practicable, de-ballasting operations should be avoided. In any event only clean ballast water should be discharged.
• Overboard discharge valves should be closed and sealed shut.
• All deck scuppers should be plugged and sealed, and any gaps in the fish plate surrounding the deck should be closed.
• Hatch covers should not be hose tested.
• Fire hoses should not be pressure tested.
• Fixed fire-fighting monitors, sprinklers and drenching systems should not be tested.
• The vessel’s decks and superstructure should not be washed down.
• Treated water from the sewage system should be transferred to a holding tank and should not be discharged until the vessel is clear of Turkish waters.
• Grey water from sources such as the galley, laundry and bathrooms should be retained on board in a similar manner.
• Steps should be taken to prevent cargo residues, incinerator ash, garbage, cleaning agents and other substances that may be construed as being pollutants from reaching the water.
• The vessel’s hull should not be scraped, chipped or painted while alongside or at anchor
Washing stubborn dirt:
When the holds are washed after particularly dirty cargoes such as petroleum coke (petcoke) and sticky coals, the washing time can be extended in an attempt to achieve a satisfactory standard of cleanliness. Coal-stains or greasy or discolored patches remaining after washing particularly if they leave dirt on hand when rubbed are likely to cause surveyors to reject the holds for sensitive cargoes such as grain, so exceptional cleaning will be required, Suitable spray foam equipment consisting of pressure tank.
Mini gun with extensions, hoses and air water nozzles can be used to deliver chemical cleaning products to a height of 10-15 meters and this type of equipment is carried as standard by responsible companies.
Use of Chemicals,
Any discoloration of the hold coating can easily become permanent if not properly cleaned after each, or every second, cargo.
The use of chemicals is becoming more common.
Studies have indicated success in protecting the paintwork (and thereby allowing easier cleaning of cargo residue), breaking down the cargo residue, or cleaning and degreasing after cargoes such as petcoke or coal, ahead of a full seawater wash down.
The chemicals should be washed off before they can dry.
The use of a prewash can protect the paint coating of the holds and allow for a much easier cleaning after cargoes which are liable to stain.
The prewash coating is applied in the same way as the cleaning chemicals (see below) and dries off as a clear protective film.
This is then washed off after discharge. Such prewash chemicals are also known as ‘fat cargo slip’. The prewash prevents the cargo adhering to the hold surfaces. Prewash is less effective on rough, uncoated surfaces such as the hold tank top.
Application in a handy-max ship takes about three (3) hours per hold. Prewash protects the paintwork and can reduce time required for painting in preparation for the next cargo.
There are a number of products available and the manufacturer’s instructions for mixing proportions and the safety precautions should always be followed.
If the recommendation is to use only freshwater to apply the chemical, this should be followed, otherwise the application may be ineffective.
Equally, without use of the proper equipment, the application may not work.
The chemicals are usually applied using special equipment including:
• chemical tank,
• mini-jet with air pressure of about 7 bar,
• lance with foam nozzles and extensions,
• personal protective equipment (PPE)
After leaving the applied chemical on the bulkhead for a prescribed time, the chemicals are washed off using a full seawater wash. The operation should always be finished with a freshwater wash. Always check the manufacturer’s guidance on compatibility with paint systems. Always check with the charterer and/or shippers regarding compatibility with the next cargo.
Cleaning chemicals which are biodegradable
(and enviromentally friendly have been develop and are reported to be effective.
After a short period to allow the chemical to take effect the treated areas have again to be washed with water at high pressure after which the offending discolored patches should be gone, except in the most difficult cases.
Spray foam equipment is not found aboard many bulk carriers and in its absence the cleaning must be done with the use of scaffolding, platforms or ladders, allowing crew members to work close up to the stains. Convenient and effective access equipment, capable of being used aboard a rolling ship is, if it exists, not well known or widely available.
A consequence is that following the carriage of coal or petcoke a final cleaning by shore labor is often required before a sensitive cargo can be carried.
Removal of taint by smell
Any extreme case of problems arising from smelly holds. For example a bulk carrier was fixed to load grain immediately after carrying a cargo of Fishmeal.
She was finally passed as load ready when inspected for the tenth time, and after thirteen days of cleaning by crew assisted, in the later stages by shore labor and equipment.
CLEANING BLOCKED BILGE SUCTIONS
Α. One suction blocked:
Prevention is better than cure, and the blocking of bilges can be avoided by sweeping of holds and lifting the sweepings prior to washing and by the use of bilge baskets to catch larger lumps of cargo residue.
Portable bilge baskets (which can be manufactured on board if not provided and are perforated (διάτρητος) steel boxes which are temporarily placed in the bilge wells to collect sweepings.They must be emptied regularly during hold washing.
This is easy done during a manual wash and can prevent problems with blocked bilges and bilge lines. Hold washing should be monitored at all times to detect any built-up of water.
If such a build-up occurs, washing operations should immediately be stopped and the problem investigated.
Directing a high pressure hose into the bilge may be sufficient to clear the suction.
Alternatively, if it is a hold eductor suction which is blocked, then “flooding back” which is possible when there is “non-return valve” between eductor and bilge well may be the quickest way to clear it. This is achieved by temporarily shutting the eductor discharge so that the water which drives the eductor is forced through the bilge suction into the hold.
If the tank top becomes flooded as the result of a single blocked suction, the hold can be pumped out by way of the other, with the ship given a small list towards the clear suction.
Since the locked suction will be located within a bilge well, and since the bilge well is likely to be from 1 – 2 meters depth, it will be necessary to remove most of the water from the well before the suction can be cleared.
If the bilge well is small in volume it is possible to bale -δεματι – it out with buckets, but if the bilge well is large one portable sump pump powered by compressed air or water at high pressure, will have to be lowered into the hold and lead to the blocked bilge where it will be used to pump the water across to the clear bilge.
Next it will probably be necessary to unbolt one or more sections of the suction pipe to locate and remove the blockage, and make the suction ready for use again.
Β. Both suctions blocked:
If both suctions are locked and the water is lying in the hold to some depth, a more serious problem exists.
Portable sump pumps may be able to remove the water but the requirement (1) to pump the water the full height of the hold for discharge on deck may mean that the process is a slow one, or that it proves to be impossible.
One alternative in these circumstances is (2) to open a manhole cover in the tank top at the forward end of the hold to allow the water to drain into a double bottom ballast tank
is can be done provided that the water at the forward end of the tank top is not too deep to allow access to the manhole cover. and provided that the water drained into the double bottom will not contaminate it.
DRYING OF HOLDS
The charter party frequently requires holds to be presented “Clean and Dry” and the requirement for a dry hold is not always easy to meet if the ballast passage is short and the hold has just been washed, or if sweat is forming in the hold.
Holds can be dried by ventilating them when weather conditions are favorable and this is a useful test of the cargo ventilation fans, where fitted.
Some ships are provided with ventilators for natural ventilation but not with cargo ventilation fans, and ships on bad weather routes may have the ventilators unshipped and blanked off.
Two steps can still be taken.
The crew can mop-up all the puddles / pools of water (λακούβες / λιμνάζοντα νερά) which form in the depressions in the tank top and other areas when a hold is washed.
If the weather is dry the hatches can opened when the ship reaches smooth waters in the port approaches, and the flow of air over the ship will help to dry the holds.
It is clear that the requirement for a dry hold is unnecessary when the intended cargo is stored in stockpile (συγκεντρωμένο) in the open air exposed to the weather and, when this is the case shippers will normally be realistic and raise no objections if the hold is damp on arrival.
This is not a reason to permit puddles / pools of water in the hold and holds should not be presented for cargo in such a condition.
When commencing the loading of a cargo of grain in winter with holds which are sweating, it may be possible to persuade the operator of the grain elevator to blow some grain dust into the hold. This will stick to the moisture and will coat the hold, thereby reducing the contact between grain and moisture. The ship sweat should not itself be a reason for holds to fail an inspection.
The inspector may require any excessive quantities to wiped dry during the inspection, but having satisfied himself that the source of moisture in ship’s sweat and not water ingress, the surveyor should accept the hold as clean.
PREPARATION OF BILGES AND TESTING OF FITTINGS
Cleaning of bilges:
When hold washing has been completed, consideration must be given to cleaning of the bilges. Bilges are cleaned to ensure that they continue to function properly and do not become blocked with residues. In addition, they must be meticulously (σχολαστικά) cleaned with every trace of matter removed and mopped dry, if foodstuffs such as grain sugar are to be carried.
Before a carrying gram or other foodstuffs, the bilges should be sprayed with insecticide (εντομοκτόνο) and rinsed with disinfectant (απολλυμαντικό) .
When presented for inspection they must clean, dry and sweet smelling. A bulk carrier bilge will normally consists of one or two bays of double bottom space from 2m3 to 10m3 in volume.
The space is usually cramped and uncomfortable to work in.
Any accumulation of cargo should be removed and when hold eductors are fitted some of this can be achieved during the final stages of manual hold washing by a man standing over the bilge well and stirring the contents with a broom, so that the maximum is drawn away through the eductor.
Whatever remains in the bilge must be dug (dig σκάβω) out with a hand shovel and lifted out of the hold by one of the processes described earlier.
Traces of perishable cargoes must never be left in the bilges, they will decay (σαπίζω) and decompose (αποσυντίθεμαι), often with most unpleasant smells.
On ships where the bilges are emptied with a bilge pump, each bilge suction is usually fitted with a perforated strum box to prevent large particles of cargo from entering the system and blocking the pump strainers.
The strum boxes must be taken apart, cleaned and refitted.
When the bilge well is inspected for cleanliness the condition of the striker plate at the bottom of the sounding pipe must also be checked.
Worn striker plates must be listed for replacement at the next opportunity to prevent damage of the ship’s shell plating.
Flashing of sounding pipes and thermometer pipes:
Hold bilge sounding pipes extend from the weather deck to the bilge wells in the hold, there normally being one on each side, port and starboard.
Hold bilge sounding pipes are essential for the detection and measurement of any water in the bilges, even when remote gauges or alarm systems exist as well.
Sounding pipes must be fit to be used when require, they must be kept clear at all times.
It is regrettable that numerous instances can be quoted to show that sounding pipes are neglected and become blocked and unusable.
This usually happens as a result of cargo residues being left in the bilge well and entering the bottom of the sounding pipe where, over a period of time, they dry out and solidity.
This problem can be prevented if the sounding pipes are flushed out, hosed out with water from deck level after the hold has been washed and the bilges has been cleaned.
This should be done as routine, with the water being removed from the bilge well by eductor or bilge pump.
Some operators use an air-line instead of a hose to flush out sounding pipes, sealing the mouth of the pipe with rags wrapped around the airline. The same alternatives are available for the flushing of hold thermometer pipes. Where fitted they must also be kept clear.
Testing of bilge suctions:
(1) If the holds has been washed out and the washing water has been discharged by eductors or hold bilge pumps, there will be no need for further testing of the hold bilge suctions.
(2) If the hold has only been swept or has not been cleaned at all, it is necessary to test the bilge suctions to ensure that water can be pumped out of the hold during the voyage if that becomes necessary.
(3) The testing of the bilge suctions can be combined with the flushing of the sounding pipes.
Putting the water down the sounding pipe into the bilge well confirms that the pipe is clear, and pumping the water out of the bilge well confirms that the bilge pump or educator is working satisfactory.
The correct working of the non-return valves fitted in the hold bilge – to – engine room lines (but not in the lines of the of hold bilge eductors which discharge directly overboard) can be tested by stopping the bilge pump or bilge educator in the engine room, and allowing water to flood back through the bilge line.If none enters the hold bilge the non-return valve is working correctly.
Non-return valves must be overhauled on a regular basis.
This should be a requirement of the ship’s Planned Maintenance System.
– High level bilge alarms when fitted, must be tested by raising the float and obtaining confirmation, usually by walkie-talkie radio, that the alarm has sounded.
The chief mate is responsible to the Master for ensuring that the holds are ready for cargo, and will normally inspect the holds himself when preparations are reported to be complete, if not before. If the crew members take an interest in their ship, it is quite likely that damage and defects noticed by crew members will already have been reported to him.
The amount of supervision for the whole process of cleaning will depend upon the experience of the crew as well as their attitude.
During the ballast passage, loose scale may form in a cleaned hold, leakage into the hold from a ballast tank may occur or undetected cargo residues may fall from high in the hold.
It is prudent to re-inspect the holds at the end of a ballast passage, some during the passage hours before the vessel reaches the loading berth, to allow time for correction of any new problems which may have developed during the passage.
The chief mate first concern will be for hold cleanliness. It has been instructed, or has read, or knows that the next cargo requires a particularly clean hold,
he will go down the vertical ladder, stopping to inspect the underside of the upper deck and the hatch end coaming as soon as they become visible.
then must look all round, using a strong torch if necessary, to check that all horizontal surfaces are clean.
He should proceed down the ladder, inspecting the bulkhead on each side and the adjacent parts of the ship’s sides.
From the tank top, he will look for residues beneath manhole cover plates, pipe guards, and inspect surfaces for residues and rust scale.
Also must check behind frames, pipes, pipe guards.
Walk around the sides and ends of the tank top, he will find whether the bulkheads, hopper sides and tank-top are clean to the touch.
Then he should walk over the tank top, listening for indications of loose rust scale, and climb the sloping ladder slowly, inspecting all visible surfaces.
He should stop at the top, inside the hold, to inspect the underside of the upper deck and the hatch end coaming.
Finally he should check the insides of any deck houses for grain and insects.
The Chief officer and the crew must be aware that some crews have been known to collect grain residues in sacks to sell at subsequent port calls.
Storage of that sort will almost certainly attract insects.
The bilge wells must be inspected.
If the chief mate finds any fault he will know that a surveyor could use it as a reason to reject the ship for a sensitive cargo, and he will ensure that further washing or local cleaning is carried out to remove the fault.
Rusty steelwork or hand scale within holds is not a reason for rejecting a ship in normal bulk trades, but loose scale is not acceptable as it likely to mix with the cargo and contaminate it Loose scale should be removed by scraping and / or high pressure washing.
Open and close hatch covers several times before starting to clean, to shake off residues and loose rust as much as possible.
Pay particular attention to hold number one.
This is often the most difficult to clean because of its shape and additional structural members.
Most surveyors will start a grain survey in that hold, and if it passes, less attention may be given to the remaining holds.
Chief Officer’s hints on surveyors’ inspection
1. non-government surveyors are usually paid for each job, not for the time taken to do a job. Anything that speeds up a survey is appreciated. So be prepared
2. the chief officer, boatswain and a crewman with a hand brush, hand scraper and bucket should accompany the surveyor, so that any spot cleaning can be carried out while the surveyor is in the hold
3. hatch covers should be at least halfway open if the weather looks like rain; otherwise they should be fully open. The surveyor will probably ask for cover sections to be ‘tented’ so that undersides can be inspected. The inside of the hatch coaming will also be inspected from the deck.
4. ensure that the access hatches at each end of every hold are open. The surveyor may go down the vertical ladder and walk up the sloping ladder.
5. bilge wells must be open for inspection.
Any trace of insect infestation in the hold or in the bilges is unacceptable with an edible cargo.
The company/managers should be consulted as soon as possible for advice about the best way of eliminating the insects without making the hold unusable for the next cargo.
Spraying with a suitable spray may be sufficient, or the hold may have to be fumigated.
Loose scale is a favorite hiding place for insects – otherwise known as bugs – and the inspection for them should be very thorough before perishable cargoes are carried.
If detected by the inspectors, insect infestation can result in expense, delay and off-hire whilst the ship is fumigated.
If they are undetected, there is a danger that the cargo will be damaged and massive cargo claims will be experienced.
Leakage from ballast tanks or other sources:
The ballast passage is probably the most favorable time to detect leakage from ballast tanks since such tanks will be full.
Leakage from ballast tanks is a regular problem with middle-aged and elderly bulk carriers.
Even if the leakage is minor it is still inconvenient. Ballast must be discharged from the leaking tank before any cargo is loaded, to avoid wet damage to the cargo, and this may be inconvenient.
It will also be impossible to present dry holds at the loading port, except by keeping the ballast tank empty.
If the leak a major one it will be easy to detect.
It will cause an additional difficulty as water drains from the leaking tank into the hold the ship will develop a list.
When leaks are found, the chief officer will note their position with great care for subsequent repair and will arrange to pump out or drop out the ballast from the leaking tank as early as possible before arrival.
The hold should have been checked for damage during discharge and again upon completion, but when the hold is dirty it is still possible for damage to be overlooked.
The chief mate, often accompanied by the Master will inspect for damaged hold ladders, air pipes, thermometer pipes, and sounding pipes and their casings (περιβλημα – πλαισιο) and damaged piping for any hold smothering system which is fitted.
Local workers in many parts of the world insist that hold ladders, with platforms, handrails and protective hoops (κρικος-στεφανι), are to be in perfect condition.
It is imperative to make sure that all is safe for the ship’s crew, too, if accidents are to be avoided.
Damage to frames, brackets and plating should also be recorded so that new damage can be shown to be the responsibility of the correct port and / or charterers.
Such damage should also be reported to Class in accordance with company procedures.
The chief mate will also satisfy himself that no cover plates for manholes or gratings (πλεγμα) for bilge wells are missing.
A good pair of binoculars, and one or two powerful hand-lamps will assist in ensuring that areas high in the hold such as the tops of the side shell frames and the frames below the cross deck strips are properly examined.
Time required for hold preparation.
The time required to clan a hold an prepare it for cargo will depend upon foll:
• the dirtiness of the previous cargo,
• the volume of residues, the size of the hold,
• the resources available for cleaning,
• the standard of cleanliness required, and,
• the number and experience of the seamen available.
A reasonable estimate is that it will take five (5) men one normal working day of 8 – 10 hours to clean one hold of a handy-sized or Panamax bulk carrier to normal cargo-ready standard from time of first entering the hold. Six (6) men aboard a Cape sized vessel will require about the same amount of time per hold. Cleaning to Grain standard will typically take about 50% longer.
Cleaning of one hold of a two (2) hold mini bulker and preparing for loading can normally be achieved by two (2) three (3) men, to a grain-ready standard, in four (4) – five (5) hours, whilst a routine hold wash and rinse of the bilge wells can be completed in one (1) – two (2) hours.
On most ships it is only possible to wash one hold at a time though other tasks in an adjacent hold can be completed whilst the hold is being washed, If sufficient labor is available.
Burlapping of bilges:
Bilge wells are usually provided with cover plates consisting of gratings (πλέγμα) or robust steel perforated (διάτρητο) plates set flush with the tank-top or recessed (εισοχές–κόχες ) into it.
They are so designed to reduce the likelihood that they will be dislodged by the bulldozes which will be used to shovel cargo into the center of the hold in the later stages of discharge. These plates or gratings (πλέγμα) for drainage are intended to admit (εισάγω) water from the hold to the bilge well and to prevent large particles of cargo from falling into the well.
Smaller particles of cargo can still fall into the bilge well so whenever dry bulk cargoes are to be carried it is normal practice to line (φοδράρω) the bilge cover plates with burlap (sacking or gunnysack). This is achieved by wrapping the burlap around the cover plate, replacing the plate in its normal position and then sealing the edges of the burlap with cement or with Ram-Nek or linen tape. After the fitting of the burlap the cover plate must remain flush with the tank-top.
If the burlap is badly fitted and raises the cover plate proud of the tank-top it is likely that the plate will be dislodged, the bilge well will fill with cargo residues and the cover plate may be discharged by mistake.
Very fine grained cargoes such as Alumina will seep through the burlap and fill the bilge well, setting hard after contact with water.
For such cargoes the bilges must be sealed with tape thereby be excluding even water.
Reseating of manhole covers:
Double bottom tanks are located beneath the cargo holds and they normally contain ballast water or fuel bunkers.
The access to each tank is by manholes set into the tank-top or lower hopper sides in the hold, though larger bulkers have additional manholes in the stool spaces.
Each manhole is closed with an oval steel lid (καπάκι) fitted with a gasket (φλάντζα-τσιμούχα) and secured with nuts, tightened on studs.
The lid will fit either directly above or directly below the manhole opening according to design.
To ensure that cargo cannot be damaged it is essential that when the manhole lid is closed a watertight and / or oil- tight seal is achieved.
Such a seal is achieved by using a gasket which is in good condition, and by ensuring that the gasket and the steel surfaces of manhole and manhole lid are all absolutely clean, smooth and free of particles of rust or cargo. When this has been ensured all the nuts must be tightened hard. When closing of the manhole lid has been completed the tank, if a ballast tank, should be pressed up (ie, filled to overflowing to test whether the closed manhole leaks)
It is not prudent to press up fuel tank, except by gravity, because the consequences of an overflow would be so disastrous, so it may not be possible to pressure test the manhole lid of a fuel tank. For that reason it is all the more important to ensure that the lid is fitted carefully and expertly if there is reason to open it. Fortunately, reasons for opening fuel tanks are much more rare than are those for opening ballast tanks.
When a manhole lid is in place, a possible steel cover plate, flush with the tank-top is normally provided to protect the recess (εισοχές–κόχες).
If the cover plate is in place it should be unshipped and any residues found beneath it should be removed. Grain has been seen sprouting from beneath these plates.
During discharge it is easy for the cover plates to become dislodged and lost if are not fitted the manhole its nuts and stubs are in danger of being damaged.
One method for protecting them if the cover plate is missing is to clean the recess thoroughly spread old cloth over the nuts, and then fill the recess with cement, smoothed off flush with the tank –top. The purpose of the cloth is to prevent the cement from setting hard onto the nuts. Cement mixed to a strength of three parts sand and one part cement is suitable. When the manhole cover has next to be opened the cement can be removed with a power chisel (καλέμι) or with a cold chisel an mallet (σφυρί).
Isolation of electric circuits:
If the intended cargo can burn or give off gas which might explode, then any electrical circuits such as hold lighting or forced ventilation circuits which pass into or through the holds or adjacent compartments should be isolated. In the case of cargoes which give off gas, the precaution must be extended to mast-houses and other compartments connected in any way to the holds by access hatch, ventilator, or sounding, air, or thermometer pipe. The most effective and reliable way of isolating such circuits is to remove their fuses and stow them in a secure place away from the isolated area. This will prevent accidental replacement. Suitable notices should also be posted when the fuses are removed.
The shippers of most cargoes will be unconcerned about the condition of the coatings of the hold surfaces, provided that those surfaces are clean and free from loose rust, but for some cargoes rust can be a problem.
(1) One such cargo is Salt used for water softening, chemical or industrial purposes,
Rust on the surfaces in the hold will discolor the salt with which it comes into contact.
If this is a possibility it will be necessary to Lime Wash the hold to coat the bulkheads and the tank-top with lime – to prevent the salt from coming in contact with the rusty surfaces.
(2) Sulfur when not treated with sodium lauryl sulphate (SLS) is another cargo for which the holds have to be Lime Washed. Lime-Wash and similar products benefit both ship and cargo.
They reduce corrosion of the ship’s structure and damage of the cargo.
Hold structures must be protected against aggressively corrosive cargoes such a Salt and Sulfur. Lime-Washing is a physical barrier application, so the thicker it is, the better the protection but the more difficult is to remove.
The more intact the paint work, the less lime-wash is required,
Lime Wash is made by mixing one part of weight of slaked lime (hydrated calcium hydroxide – CA(OH)2) with three parts fresh water. (1 προς 3)
Lime mixture. Prepare 200 liter empty drums with about 50-75 kg of lime plus 2,5 kg of sugar. Fill the drum with hot or warm fresh water and mix thoroughly.
A handy-max bulk carrier will use about 1200 – 1500kg of lime.The mixing quantities will vary according to the condition of the paint work and other factors. The lime wash can be applied to the bulkheads with a (1) roller, (2) the hose of a portable sump pump, the pump being used to draw the wash out of the drum. Alternatively a (3) high pressure Spray-Jet gun with a suitable nozzle or (4) even paint spray equipment can be used. It will be necessary to lime wash the bulkheads to whatever height the cargo is expected to reach in the holds, but the deck-head should not be lime washed as the lime- wash will be difficult to remove at the end of the voyage.
The aim must be to cover bulkheads and tank- top with a good, thick even coat of lime-wash.
Special attention paid to areas behind frames and to inaccessible places. No bare metal should be visible.
Sometimes a second coat may be applied if, during drying, rusting is visible through the lime-wash, as this may stain certain cargoes,
The lime-wash will dry in a few hours.
Surveyors often require the removal of lime-wash before the carriage of sensitive cargoes such as foodstuffs, fertilizers, mineral sands and concentrates and removal by washing is sometimes very difficult and time consuming. It is claimed that hold cleaning chemicals, applied by high pressure Spray Jet gun, can make the removal of lime-wash much easier.
REM Hold Block: (RBM Hold solutions product literature, Vancouver British Columbia 2002).
It is a biodegradable environmentally friendly semi-permanent coating or barrier developed to take the place of lime-wash for the carriage of Sulfur, Salt, Sticky Coal, and Petcoke, It is said to be easy to apply, over paint or rust, at heights up to 13 meters using an application set consuming of air powered pump, spray nozzles, extendable power wand and appropriate hoses, which can also be used for hold washing chemicals.
RBM Hold Block is claimed to be much more effective than lime-wash and is easy to remove by washing down following the application of Hold-Wash-AP , another of the company products. First reactions from the shipping industry appear to be favorable.
It is not possible to paint over RBN Hold-Block and development work, to ensure that it can be seen clearly for removal, is continuing.
Painting of holds:
Opportunity is sometimes taken, on ballast passages or during a period at anchor , to touch up hold paint work or to repaint holds.
When such work is considered it should be remembered that receivers and authorities in importing countries are becoming increasingly determined to ensure that foodstuffs are not contaminated with any harmful substance and that holds have been rejected because of taint (αλλοίωση-βρωμιά) from the smell of recently applied paint.
When foodstuffs are to be loaded and when a hold has been recently painted, the authorities in some countries insist on seeing evidence that the coating will not harm foodstuffs.
The Paint Compliance Certificate may be required by many shippers or local authorities before cargo can be loaded is an example of the sort of evidence that may be required.
If the ship possess no certificate for the paint and there is doubt about the wisdom of painting, managers/company should be consulted If the holds need painting, sufficient time should be allowed to cure and dry the paint.
Unless advised otherwise by manufacturers, seven days should be adequate in a well ventilated hold.
Epoxy coatings appear to be the most common paint used for holds.
When next cargo is for example petcoke – stains from petcoke are difficult to remove – we can protect the hold paint before loading with prewash or barrier chemical.
Such chemical must be compatible with any food stuff cargoes.
The importance of coatings.
The primary role of coatings is to protect assets from environmental corrosion, in order to provide as long a service life as possible.
Not only does corrosion affect:
(1) service life,
(2) it has a real and detrimental effect on costs to the asset owner in terms of service time,
(3) performance levels and,
(4) asset value.
To preserve the life of a vessel there are some key considerations that should be taken into account. Two common causes of coating failure are related to coating thickness.
Both (1) over and (2) under application of the protective coating have the potential to cause problems. under-application of the protective coating can, and does, lead to early coating failure, with scattered corrosion in areas of under-film thickness
It is therefore important that the paint manufacturer’s guidelines are adhered to.
Another problem that can occur is the development of (3) cracking.
This can happen due to the build-up of stress.
Cracking is a problem that is particularly associated with welds and corners – where there is a change in geometry.
Once the paint has cracked, under-film corrosion can occur which then results in paint detachment.
The main tools used to apply paint on board ship are brush and roller.
It is very easy to under apply paint when using either of these tools as the tendency is to spread out the paint too thinly.
Even though the required number of coats of paint may well have been applied (as per paint manufacturer’s technical data sheet), the repair is likely to be under the recommended coating thickness. This under application means that the repair patch is not able to perform properly as a corrosion barrier, and as a consequence, the repair can break down.
When breakdown occurs, which can happen during normal operations at sea, repairs should take place at the earliest opportunity.
Depending on the cause and extent of coating failure it may be possible to repair the damage by making patch repairs. There are two situations, however, where this is not realistic:
if the coating has been over-applied, or if the surface has not been properly prepared. In the case of the former, it is possible that over-application may result in detachment in other areas over time.
In the case of the latter the newly applied paint may suffer from the same adhesion problems as the old paint.
If poor surface preparation is the cause of paint detachment, then the only solution is to remove the paint and start again. It pays to get it right first time!
Paint coatings on vessels may be viewed as a minor consideration, but incorrect application or poor maintenance can lead to significant costs.
Repairing coatings offshore can be up to 100 times the cost of the initial coating, and $2 trillion is spent each year on tackling corrosion.
With proper preparation, ship-owners / managers can ensure that vessel is performing at optimum performance and can reduce the time and money spent on preserving the condition of their assets.
Ballast hold can be used either to hold ballast or to carry cargo.
1) When cargo is to be carried it is essential that the proper steps are taken to ensure that ballast water cannot be admitted to the hold by accident.
The procedures may have to be done, hurriedly, in the loading port since the hold may have been used for ballast during the previous ballast during the previous ballast voyage.
There is likely to be a conflict of interests between the requirements for cargo and ballast, particularly when low density cargoes are to be carried, filling all cargo spaces including the ballast hold.
All such times may be difficult to find time and opportunity to clean the ballast hold at the start of the ballast voyage, before the hold is ballasted.
Where possible the hold should be washed or failing that, swept. If a hold is ballasted without removal of sweepings as a result of pressure of time, problems with blocked suctions will almost certainly be met at that time of de-ballasting, when the hold may be urgently required for loading.
(2) Before ballasting.
Because of the time pressure which often exists when ballast holds have to be clean and ballasted, it is useful to consider the priorities:
• Before a ballast hold is ballasted the ballast line must be unsealed, and the bilge line,
• The CO2 injection and the coaming drains must be sealed.
• Any sweepings or rubbish which could block the ballast suction must be removed from the hold.
• If the next cargo will or may require a high standard of cleanliness, the hold should be meticulously cleaned.
• If the ballast water is dirty, there may be an opportunity to be de-ballast the hold and clean it during the voyage, if stress limitations permit, refilling with clean sea water thereafter if necessary.
• If there is no opportunity to clean the hold of ballast sediment at sea and a clear hold is required quickly in the load port, the crew can usually commence hosing down the open hold from deck level while the ballast is still discharging and can either the hold to continue washing down when the water level reaches 30 – 40 cm over the tank-top.
• It is important to remember that written permission to commence de-ballasting is required in many ports.
When the ballast has been discharged and washing down, if required, has been completed a fresh water rinse will be required for cargoes which require holds which are free of salt.
On completion of washing and rinsing the bilge suction, the CO2 injection and the hatch coaming drains must be opened and tested, and, the ballast suction must be blanked off.
Sufficient time to complete these tasks must be provided in the loading plan.
CHECKLIST – Items for attention when preparing holds for cargo
• Decide how much hold cleaning is required.
• Encourage the stevedores to discharge cargo sweeping as far as possible.
• Have crew or stevedores sweep down deck heads and bulk heads as discharge proceeds – for example with grain cargoes.
• If cargo has filled a bilge have crew clean it before completion of discharge, so contents can be discharged.
• Clean coamings thoroughly with air hose before securing hatches for sea.
• Wash undersides of hatch covers and comings finishing wash with fresh water, in sheltered waters.
• Sweep holds before washing to remove bulky cargo residues, if required.
• Sweep holds instead of washing when washing is not necessary.
• Scrape and sweep holds and lift residues from hold when washing is not possible.
• Land cargo residues or store on deck for later disposal.
Holds will not be washed if:
• Vessel will remain in areas where discharge of washings is not allowed.
• Same cargo is to be carried again and the charterers want no cleaning.
• Clean cargo like steel coils has been carried.
• Freezing conditions do not permit washing.
• The cargo residues will react adversely with water, eg. they will set hard.
• Decide if full wash or bottom wash is required, and if washing is to be done by automated washing or by portable hose.
• Decide if washing is to be done at berth, within port limits or outside limits, taking account of any restrictions on discharge of cargo residues and anticipated weather and sea state.
• Obtain written permission from port authority to discharge hold washings if intend to wash in port.
• Wash hatch covers, top, bottom and sides.
• Scrub hatch cover compression bars and rubbers if necessary to remove cargo traces.
• Wash hatch coamings
• Wash underdeck areas
• Wash hold sides, paying particular attention to hopper angles, pipe guards, brackets and other non-vertical surfaces.
• Scrub locally and /or rewash to remove stubborn dirt.
• For stains or stubborn dirt apply cleaning chemicals and later rinse off.
• Wash tank top, scrape up loose rust scale.
• Flush bilges.
• Rinse holds with fresh water to reduce corrosion and to prepare for cargoes which must not contact salt.
• Dry holds ventilating, by opening holds and/or by mopping up puddles, as necessary
• Clean and isinfect bilge wells.
• Flush sounding pipes and thermometer pipes.
• Test bilge suctions if not already used for washing.
• Test bilge non-return valves, when fitted.
• The bilge high level alarms, when fitted.
• Test hold water ingress detectors.
• Inspect holds for cleanliness, insect infestation, taint, leakage and damage. Remedy defects where necessary.
• Wrap bilge cover plates with burlap and secure with tape or cement.
• Reseal any manhole covers which have been opened or disturbed.
• Isolate hold lighting and lighting in compartments connected to the holds, when this precaution is required for intended cargo.
• Lime wash bulkheads and tank top if required for next cargo.
• If holds are painted, or touched up, before a cargo of foodstuffs is carried, ensure that a paint compliance certificate can be produced for the paint used and that paint has sufficient time todry.
• In ballast holds, close and secure cover plates for ballast suctions, and open bilge suctions, coaming drains and CO2 injection lines.