We, Constellation Marine Services LLC as independent ship and marine surveyors, often get nominations from our principals to carry out Hold Cleanliness inspections. Recently we got a nomination from one of our clients to carry out Hold cleanliness Inspection on board 34778 GRT Bulk carrier and report on its fitness to load intended cargo (PRILLED/GRANULAR UREA). Our Naval Architect/Marine Surveyor upon in receipt of instruction, arranged to attend an inspection on board the subject vessel at Anchorage.
PREPARATION OF CARGO HOLDS:
- Vessel was built in 2012 & designed with five cargo holds. Hatch cover are of Steel, End folding type. Vessel was designated to load PRILLED/GRANULAR UREA of 38500.00 MT.
- Vessel was carried Limestone in her last voyage. Chief Officer has ballasted all 5 cargo holds during her en-route from disport.
- During our inspection Hold No.3 was still in ballast condition. Remaining cargo holds were de-ballasted & rinsed with fresh water. No cleaning agents/chemicals were used to clean the cargo hold.
WHY CLEANLINESS OF CARGO HOLDS SO ESSENTIAL WHEN THE VESSEL LOADING INCOMPATIBLE CARGO LIKE GRANULAR UREA..?
- Preparation of holds depends upon the next cargo, if next cargo is compatible with the previous cargo, a fair sweep down & removal of leftover cargo is sufficient. However if next cargo is incompatible with the previous cargo comprehensive cleaning is mandatory.
- Urea is made from a synopsis of ammonia & carbon dioxide. During transit ammonia present in the UREA will be vented & it will react between the loose paint and the steel structure which leads to corrosion. Again it will come to more concern when the UREA is wet because the scourging effect of UREA is considerably higher when compared UREA in dry condition.
- Pure/Impure UREA in the existence of moisture can damage paintwork or it would corrode steel structures.
INSPECTION OF CARGO HOLDS:
- White glove test has been carried out in ships structures like frames, brackets, hoppers & under deck channels. All the cargo holds were observed dry & bilge well covers were opened.
- Bilge & drainage suctions has been tried. Holds were observed taint free. Stains marks at frame sides were observed however same has been rectified by vessel staff.
- No residues of previous cargo or loose rust were observed. No existing physical damages to ship structures were recorded.
- Bilge wells were observed dry & burlap covered in presence of Constellation Surveyor after inspection.
- Sounding pipes/ventilation pipes were observed free of rust. Double bottom tank manholes were tightened.
- Cargo hold ventilation system were inspected.
INSTRUCTIONS TO VESSEL:
- Cargo holds should not be ventilated during loaded voyage.
- Hatch covers should be weather tight. ULD test of hatch cover would be recommended before loading incompatible cargos.
- It should be recommended to pressure test the ballast lines if vessel intent to take heavy weather ballast during her voyage.
- All non-return valves on the bilge lines should be overhauled on a regular basis by vessel staff.
FILE PHOTO FROM ARCHIVE:
Prepared by Engr. Vignesh Prabhu. A.
Naval Architect/Marine Surveyor.