The ship was operating under UMS class. During one of the voyages, around 2230 hrs, alarm came to the duty engineer’s cabin, and before it could be acknowledged, there were series of alarms and power went off creating a black out. Emergency power came on automatically.

The ship was in Caribbean waters. Main engine stopped due to black out.On inspection, found that the FO pressure was low for the auxiliary engines, hence C/E instructed others to clean all the fuel line filters and to recommission the generators. It was done, but after sometime (nearly 30 mins) again there was a black out and main engine stopped. Filters were found choked. Since the engines had duplex filter, it was decided to proceed by changing them and cleaning the choked ones frequently, till the vessel can make to the port.

The vessel reached the port safely next day morning, and after informing the port authorities regarding possible shut down, the tank valves were inspected after transferring the oil. It was found too much of sludge in the valve and the pipe line. All fuel lines were cleared off this sludge, and the auxiliary engines were started on DO to carry on the cargo work. FO tank man hole doors opened up and after sufficient venting and taking all precautions, the tank was cleaned. The purifiers were checked up for proper operation and the feed was adjusted to ensure maximum sludge separation.

The auxiliary engines were changed over to FO once everything came under control.On referring to the records, it was observed that the fuel tanks were not cleaned in the last 4 years, and also the quality of the bunker oil was getting changed every time depending on the owner’s choice (mainly price differential), the mixing of different grades and incompatability led to such huge sludge accumulation. The owner’s were advised accordingly.It is imperative that the tank condition is maintained to avoid such mishappenings. It is also advisable to check the purifier output once in a while and also the tank draining can be properly done and the frequency of draining can be increased.