While en route near the west coast of Africa, a fire broke out in the engine room of a ship. The fire spread into the accommodation areas resulting in the death of the Third Engineer. The incident caused substantial damage to the engine room and the accommodation space.

The investigation revealed that the fire was caused by the overflow of heavy fuel oil from the boiler fuel oil tank. The fuel oil was ignited when it came into contact with the hot main engine exhaust manifold.

The primary cause of the fire was that the Junior Engineer mistakenly opened the filling valve for the boiler fuel oil tank in fuel transfer. This mistake was unfortunately compounded with two major defects on the boiler fuel oil tank system. Firstly, a length of the boiler fuel oil return line had been removed leaving an opening on the top of the boiler fuel oil tank. Secondly, the overflow line for the boiler fuel tank was blocked with rusty debris. As a result, excess fuel oil could not be drained away through the overflow line but flew out from the opening at the top of the tank and came into contact with the hot main engine exhaust trunk.

LESSONS LEARNT

•	No modification of any fuel oil system should be made without prior approval from Flag Administration or Classification Society.
•	It is utmost importance that overflow pipes for fuel and lubrication oil tanks are properly maintained for the intended services.
•	The modified pipeline should have been isolated/blanked and a notice posted to prevent inadvertent use.