Water Logging of Coal Cargo
Challenges
- Coal cargo always contains moisture. Water spraying is required from eco and fire prevention angles.
- Normally, coal cargo being lumpy does not promote liquefaction.
- Further, when water/slurry takes place in one hold, cause rendered complex. From liability angles, cause plays on important part.
- Although there was water logging of cargo, it was not getting drained into hold bilges in final phase of voyage to India. As bilge pumping was effective, choking and clogging of bilge wells, burlaps emerged as the most likely cause. In turn, clogging of burlap attributable to fine particles of cargo.
- The presence of submerged cargo by free water/slurry poses risks and hazards.
- Thus, apart from liability angles, from prevention of accident/mishap/safety perspective, cause rendered important. Although, powdery coal serves as pulverized coal, pulverization carried out only at the time of end use.
- Most ships use eductor system for Bilge pumping requiring higher filtration. Thus, ships staff may use finer burlap in the event cargo contains finer dusty cargo, which lead to choking/ clogging of bilge walls and water logging thereof. Variation in cargo composition in holds cannot be ruled out in one lot or shipment.
Background
- The Vessel loaded 38,500 MT Coking Coal from two US Gulf Load Ports on East Coast for one or two Discharge Ports on West Coast of India.
- Voyage to India was via Cape of Good Hope. Seasonal weather experienced during the voyage.
- Nominated quantity for discharge at New Mangalore was 16500 MT from two Holds. During breaking bulk of two holds. Cargo in one hold was found submerged under water layer. Telltale marks on hatch coaming sides indicated slurry movement within the hold. Receivers expressed refusal to accept the cargo due to terminal constraints and switched holds for unloading.
- Vessel was time Chartered by head Disponent Owners, further sub chartered to Disponent Owners and then voyage Charterers.
- However, after discharging 2500 MT of cargo, slurry form of wet cargo was encountered and loading operations defers thereafter.
- Protests exchanged and P&I Surveyors involved. The Silver Nitrate Test on water was negative, ruling out sea water entry.
- Water quantity in one hold was estimated 105 MT.
- Discharge quantity at New Mangalore reduced to 8750 MT.
- All Hold Bilge Records were perused. Bur lapping of hold bilges and bilge pumping was found in order. Water logging of cargo attributable solely due to cargo quality composition.
Action Taken
First towards dealing with slurry and secondly towards ascertaining cause.
The employment of Vessel was two Indian disports i.e. New Mangalore and Goa (Mormugao).
From geographical and logistics angles, second Port of Mormugao was geared better for handling slurry associated cargo.
Hence, to deal with slurry, slurry cargo was left for second disport, which had better dewatering (submersible pumps etc.) logistics.
Regarding converging on cause, quality and nature of water was important. Bilge/Ballast Management and operation was checked.
Stability calculations had to be provided to Port State Control as free surface effect emerged from a water filled hold.
The Vessel eventually was taken to a third Port in India. The cargo was discharged by grabs in the slurry form onto a concrete apron quay where the water was drained out naturally from the cargo stock pile.
There has been no damage to the cargo nor had any cargo caking formed. The slurry formation created unloading logistic problems which resulted in time delays and discharge costs with Vessel calling to a third port.
Lesson Learnt
It is recommended that all parties strictly adhere to the requirements as laid out in IMSBC Code of Group A Cargoes and follow sampling procedures laid out accordingly. Lapses had occurred in this regard.