- 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.
- If the ship has been carrying DRI (direct reduced iron), the dust created by this particular cargo during loading or discharging, will be carried to all areas of the ships structure and the reaction between iron, oxygen and salt will create an aggressive effect wherever the dust may settle. This is particularly noticeable on painted superstructures.
- All excessive cargo residue has been removed then the holds can be washed with salt water using a highpressure hold cleaning gun, supplemented by the deck air line to provide increased pressure.
- Whenever salt water washing is used to clean hatches, the relevant holds should always be rinsed with fresh water to minimise the effects of corrosion and to prevent salt contamination of next
- Prior to high pressure hold washing, excess cargo residue on the tank top should be removed by hand sweeping and lifted out of the holds via the use of a portable mucking winch.
- After washing-down, holds must be dried properly and ventilated. Additional preparations should be applied as required, for example lime washing.
- If chemicals are to be used as part of the washing-down procedure, agreement on compatibility with the next intended cargo must be sought from the shippers/ charterers.
- Hatch watertight integrity
- To prevent cargo claims due to water ingress, all hatch seals (both longitudinal and transverse), hold access lids and seals around the hatch sides should be chalk marked and water tested using deck wash hoses.
- A more accurate method of testing a hatch for leakage is to use ultrasonic equipment.
- Special attention should be given to cargo residues wedged behind pipe brackets, hold ladders, and on the under-deck girders and transversals.
- Special attention should be paid to ventilators to ensure that remnants of previous cargo have been removed and the area is grain clean.
- Hold bilges and recessed hatboxes should be cleaned out and all cargo remains removed.
- Bilge suctions must be tested both before and after washing and the results entered in the cargo notebook and/or deck log book.
Regulations for discharge of wash water:
- While disposing Cargo residues and Wash down water, the Chief should ensure that MARPOL 73/78 are strictly followed.
- MARPOL 73/78 Annex V requires that all ships of 400 GT and above have an approved Garbage Management Plan and a Garbage record book.
- Cargo residues, wash water and wash water containing chemicals which are Harmful to the Marine Environment (HME) must be identified as such and disposed of in the correct manner. From 1 January 2013,
- New requirements under MARPOL annex V have come into force, which specifically apply to the disposal of cargo residues and wash water in to the marine environment. All persons involved in the cargo chain must familiarise themselves with these requirements. They basically state that:
- No discharge of cargo residues should occur less than 12 nautical miles from the nearest land, or the nearest ice shelf.
- No discharge of cargo residues should occur within the MARPOL defined ‘Special Areas’.
- No discharge of any cargo residues specified as HME.
- Hold wash water should be discharged to a suitable reception facility (RF).
Washings containing hold cleaning Chemicals
These chemicals could be in themselves be pollutants. If the substance falls within Annex 1 (Oil) or Annex II (Noxious Liquid Substances), then the washing will have to be disposed to the Annex requirements.