In the most recent update of the American Club’s “Good Catch Series”, lessons learned are provided from an incident when a fuel oil tank was overfilled causing an oil spill.
The incident
What actually happened was a bulk cargo vessel had been bunkering. The bunker operation was planned in advance, and the Chief Engineer conducted a detailed pre-bunkering meeting to coordinate the operation.
However, the pumping rate from the bunker barge was significantly higher than planned and not approved by the Chief Engineer resulting in the bunker tanks filling faster than expected.
When the engineer taking soundings determined that the fuel oil tank being filled was at 80% capacity, he assumed that another 10-15 minutes of pumping would fill the tank to the planned 90% capacity.
But because of the higher pumping rate, the tank overfilled resulting in a substantial amount of fuel oil spilling out the tank vent before the pump could be shut down by the barge crew.
The oil containment around the vent was overwhelmed as were the scuppers. The scupper plugs worked as intended in some locations, but in other locations they were not sufficiently snug, and oil leaked past them and down the vessel’s hull into the water.
The vessel activated their oil spill response plan. The crew and local spill response resources deployed oil boom to contain the spill and numerous square absorbent pads inside the confines of the boom to soak up the oil.
Lessons learned
- Prior to the start of the operation, do you ensure a common understanding with the bunker barge crew of the desired fuel oil delivery rate?
- How do you ensure that the bunkering operation is happening consistent with the bunkering plan, including the fuel oil delivery rate?
- Do you verify that communications are adequate and reliable between the vessel and the bunker barge?
- How do you monitor tank levels during the bunkering operation? Do you use more than one method to monitor tank levels?
