200877 Bilge water overflow

Our vessel arrived in a US port with an excessive amount of oily water collected in engine room bilges. This accumulation had resulted from maintenance work which had been carried out on several heat exchangers during the voyage. Disposal of bilge water through the oily bilge separator was not attempted for a prolonged period as the vessel was in coastal waters and the ship's staff had doubts about the efficiency of the filtering equipment.

After berthing, the second engineer set up the lines to transfer the bilge water to the bilge holding tank. Soon after transfer was commenced, oily bilge water overflowed from the bilge holding tank vent pipe on deck. This was noticed by the alert deck crew and the transfer operation was immediately stopped, deck scuppers were plugged and the shore authorities were alerted promptly.

Clean up operations were carried out by the contracted oil spill response company.

Root cause/contributory factors
1. Even though the second engineer was in charge of the operation, he had in fact assigned the cadet to carry out the task, while he attended to other jobs in the engine room;
2. The cadet suspected an obstruction in the forward suction and so he closed that branch valve and was engaged in cleaning the filter. Meanwhile transfer from aft bilge well continued without anyone checking the holding tank sounding;

Editor's note: Why the transfer was not attempted earlier is not explained, as accumulation of water in the engine room bilges presents a pollution threat and also a fire hazard if oily residues are present. The company's safety management system (SMS) must contain written procedures and checklists covering oily bilge transfer and discharge operations.

Readers are reminded that entries in the oil record book must scrupulously document all transfers and discharges of oily mixtures and also record malfunctions of the filtering and discharge monitoring equipment.