SA 014 Cargo Damage due to Water Ingress from Ballast Tanks and Bilge Lines

Incidents resulting in damage to dry cargo following water ingress into the holds from ballast tanks and bilge lines continue to arise. Such claims are usually costly, and separating damaged goods from the rest of the cargo can often cause delay. Moreover, when cargo has been damaged by salt water, the salved value may be minimal and disposal may be necessary, adding to the magnitude of the claim.

Water Ingress from Ballast Tanks

Water from ballast tanks may enter adjacent cargo holds via a number of different routes:

 Damage to the hold structure. This fertilizer cargo was damaged by sea water migrating from an adjacent holed ballast tank This may be caused by cargo operations, for example, due to grab damage to tank top plating unchecked due to the difficulty ballast filling/suction arrange- or hold pipework on vessels of examining this area and ments. This may be due to carrying dry bulk cargo. removing rust scale. Where valves between the ballast main Similarly, container vessel tank inspection of the pipework and hold or overboard drop tops may be damaged by within a hold is problematic this valves not being closed, or containers which are landed should be conducted during when blanking plates have not heavily or if lashing material each dry docking period. been properly fitted to the becomes trapped between tank suction/filling arrangements top and the container base.  Leaking ballast tank manhole within the hold when the system covers. This may be due to is not in use.  Severe corrosion of ballast tank failure of the gaskets or the steelwork. This may involve presence of debris preventing a When the Club carries out plating where localised suitable seal when manhole condition surveys of dry cargo corrosion is so severe that covers are refitted, or when vessels, the ballast tanks holes have appeared, or ballast manhole cover securing nuts surrounding the cargo holds are tank air and sounding pipes in and bolts have not all been tested hydrostatically. The test will holds where the blind side of replaced or properly tightened. only be conducted when pipework close to the adjacent shipboard operations and local steelwork has corroded  Cargo hold heavy weather regulations allow and when the

Cargo Damage due to Water Ingress from Ballast Tanks and Bilge Lines cargo holds in question are empty. non-return valve in operation bilge line isolation valves The ballast tank is overflowed to should be investigated. If the reminding crewmembers that they deck and the cargo holds adjacent screw down valve between the should be shut once the pumping to the tank inspected for leaks. bilge line and the bilge pumping of bilges has been completed. However, such a practice only system/eductor is not closed and confirms that the tank is not bilge/general service/ballast In order to prevent debris and leaking at the time of the test. It is pumps are subsequently cargo residues from entering the therefore recommended that, as operated, sea water may flood bilge line and affecting the far as is safe and practicable, back along the bilge line, past the operation of the non-return valve, ballasting operations are only non-return valve and into the a strainer/strum box should be undertaken when the adjacent cargo hold. fitted to the end of the bilge cargo holds are empty of cargo, suction pipe. When carrying dry recognising that this may not It is recommended that the bulk cargo, suitable protective always be possible due to inspection, maintenance and measures should be taken to operational reasons. testing of cargo hold bilge line non prevent cargo migrating past the -return valves are incorporated bilge well plate into the bilge well. If a ballast tank manhole within a into the vessel’s planned When cleaning holds after the cargo hold has been opened for a maintenance system, including discharge of dry bulk cargo, bilge routine inspection, to carry out checks for backflow past the non- well plates should be removed maintenance or while in dry-dock, return valves when bilges have and all traces of cargo residue and the manhole cover should be been pumped dry. Non-return debris cleared from the bilge well. refitted carefully on completion so valves and bilge line isolation that the tank is ready for use. screw down valves should also be If bilge high level alarms are fitted, Checks should be made to ensure opened periodically and inspected they should be tested periodically that sealing arrangements are free for obstructions and the build-up to confirm that they will operate of debris, that the gasket is in of cargo residues to ensure that correctly if water accumulates in satisfactory condition and they remain effective. Where bilge the bilge well. Regardless of such renewed if necessary, and that all suction lines pass through ballast alarms, bilge well soundings nuts and bolts are in place and tanks, the pipework should be should be taken and recorded correctly cross-tightened in order checked for excessive corrosion twice daily as a matter of routine to achieve a watertight seal. during routine ballast tank internal as there have been many cases of Provided no cargo is present in inspections. water building up in a hold the hold, it is recommended that undetected due to the sudden and the tank is then checked by Crew members engaged in unexpected failure of a bilge high means of hydrostatic testing at the pumping cargo hold bilges should level alarm. Any activation of a earliest opportunity to confirm that ensure that all valves isolating the bilge high level alarm or build-up the manhole cover does not leak. bilge lines from bilge/general of water in a bilge well should be service/ballast pumps and investigated immediately. Periodic hydrostatic testing of eductors are closed upon ballast tanks should also be completion of pumping bilges. Members requiring further considered as part of a vessel’s Consideration may be given to guidance should contact the Loss planned maintenance system, posting warning notices next to Prevention department. conducted at suitable intervals when the holds are cargo free. In addition, if a sounding or remote monitoring of a ballast tank reveals an unexpected reduction or increase in the tank’s contents, a thorough investigation should be carried out to ascertain the cause of the change.

Water Ingress from Cargo Hold Bilge Lines

Cargo hold bilge systems are fitted with a non-return valve on each bilge line, normally within the bilge well above the strum box/ strainer. The non-return valve can become blocked, either by cargo residue or by rust or debris such as rags, preventing it from closing JoinerMarine Services, Mobile, AL. properly. Non-return valves can Photo: also seize open or partially open; Rust and debris blocking this bilge well non-return valve allowed sea water to a lack of an audible clanking of the migrate into the hold during ballasting operations, causing cargo damage