Lessons Learnt: Bunker Spill

Bunker Spill
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Vessel Type: Bulk Carrier 

Incident description 

At the time of the incident the subject vessel was alongside loading bulk cargo. At the same time heavy fuel oil was being loaded from a bunker barge. Weather conditions were good but it was very cold (-20C°) and there was thick ice and snow on deck.

Prior to bunkering, all relevant checklists were completed in accordance with the bunker plan and the relevant bunkering procedures under the vessel’s SMS. 

All necessary safety precautions were taken by the crew and all necessary entries were recorded in the deck and engine logbooks. All deck scuppers and savealls were correctly plugged and secured. 

Prior to starting operations, a maximum pumping rate of 250m³ per hour was agreed between the vessel’s Chief Engineer and bunker barge skipper, who confirmed that the supply temperature of the bunkers would be around 35C°.  

The plan was to fill bunker tanks 3 port and 3 starboard, followed by 2 port, then 4 port and 4 starboard. The subject tank, 2 port, was to be filled to approximately 82% of total volume, about 292m³.

In the event, loading of fuel commenced into 3 port and 3 starboard at about 17:30 and was completed at about 20:00. On completion, 2 port was opened up and started to fill in the normal way.

At 21:00, a manual sounding of 2 port was taken by the duty engineer, which corresponded to the tank being roughly 60% full, or 215m³. Everything appeared in order and the next sounding check was planned for 21:20. 

At 21:15, bunker fuel was observed spilling out of the vent on deck. The saveall was overflowing and fuel was running down the deck and over the side. Pumping operations were stopped immediately. 

In the event, the majority of the oil spilled was successfully contained on deck, however a small quantity found its way over the side and into the water.


Investigations revealed that due to the extreme cold weather the level of fuel in the sounding pipes increased at a slower rate than the tanks themselves; therefore the readings taken via the sounding pipes were inaccurate.

Lessons Learnt

  • Additional considerations should be taken when bunkering in conditions of extreme cold;
  • The bunkering plan must be discussed and understood by all crew involved in the bunkering operation;
  • Relevant cold-weather SMS procedures must be taken into account; 
  • If in doubt, crew members should slow the rate of the bunkering and seek assistance;
  • Crew members must remain vigilant at all times and ensure that tank soundings are taken properly and regularly, that they make sense and correspond to the agreed pumping rate.

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Staff Author