| On this vessel, sludge is routinely transferred from the sludge holding tank to the incinerator slude tank every two to three days, ensuring that the latter tank does not contain more than 80 per cent capacity at any time.
In this incident, the duty engineer and a rating were involved in the transfer of sludge during the night, with the pump in manual mode. After attending to a telephone call, the engineer completely forgot about the transfer operation and both he and the rating left the engine room after changing over to unattended machinery spaces (UMS) mode.
The transfer continued unsupervised until the overflow from the incinerator sludge tank vent on the funnel deck, amounting to about 150 litres, was noticed by the night bridge watch.
Root cause/contributory factors
- Distraction caused by telephone call during a critical operation;
- Ineffective teamwork between engineer and rating;
- Sludge transfer being conducted at an unusually late hour.
Other valuable lessons
- A risk assessment must be carried out for all oil transfers, which shall be referred to on each occasion that the task is carried out.
- Under normal circumstances, oil transfers should only be carried out during the day.
- Personnel involved in oil transfer operations shall not be assigned to any other task, and must not allow themselves to be distracted.
- When two crew members are working as a team, it is essential that each knows what the other is doing and only one of them must answer telephone calls.
- Critical operations that are in progress should be prominently noted on the engine room notice board. Even temporary memo notes, placards etc on the console, exit door, log book may be of great value.
- The bridge team and the chief engineer should be kept informed of any manual oil transfer operations being conducted, giving details of the tanks involved, estimated quantity and expected time of completion.
- If the transfer pump has an auto cut-off device, it must be used and properly maintained.
- Wherever fitted, tank high-level or overflow alarms should be effectively used.
- Portable timers or other pre-set alarms can be very useful as reminders.
- UMS checklist must contain a reference to oil transfer activities and must be jointly completed by the duty engineer and rating, if appropriate.
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