Accidents Case of Study

Lessons Learnt: Oil spill during bunkering

Vessel Type: Bulk Carrier

Incident description

This vessel was stemmed to receive 250 MT of IFO 380 from a barge whilst alongside. The bunkers were to be received in a pair of empty top side tanks, each with a full capacity of 200 cubic metres. As per company management procedures, bunker tanks were not to be filled in excess of 85% capacity, which in this case corresponded to a minimum ullage of 55 cm. The Third Engineer (3/E) was placed in sole charge of performing the bunkering operation, which was commenced into the starboard side tank only at 15:20 hours. At 16:30, the 3/E recorded the ullage of the tank as being 51 cm and yet bunkering operations continued. At 16:35, he saw that the ullage had reduced to 35 cm and rushed to the engine room to divert the bunkers into the port side tank. However, by the time he reached the valve station, the starboard side tank was already overflowing on deck, with oil being spilt overboard.


This was a very poorly planned bunkering operation from the outset with an almost complete neglect of the company SMS procedures. The bunkering checklist was ticked off but not in fact implemented. The 3/E should have been supported by another member of the engine room staff during the operation and in ready communication with the bunker barge. Consideration should also have been given to filling both port and starboard tanks at the same time.

The tank overflowed from both the forward and aft air vents. At the aft vent, the oil was not contained within the saveall as the vent head was located immediately adjacent to the side plate, allowing oil to land directly on deck. At the forward vent, oil was able to escape because the saveall drain plug was not fitted. Although the main deck scuppers were plugged, oil was still able flow over the deck containment and into the dock.

Lessons Learnt

  • Bunkering operations should be performed in strict compliance with SMS procedures
  • Bunkering plans are to be carefully considered by the chief engineer and checklists diligently completed at the site of the task, not just a “tick box exercise”
  • Bunkering is not a one man job. It requires teamwork and established communications with ship and barge personnel
  • The pollution may have been avoided with better design of the tank vent and saveall arrangements.
  • A saveall is not a saveall if the drain plugs are not fitted or missing!

Source: UK P&I Club

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