The incident

Engineers on a bulk carrier were conducting scheduled maintenance on one of the ballast pumps. They had closed all the isolating valves to the ballast pump and put up notices about the job in the engine room and engine control room, but not on the bridge. They didn’t finish the job on the first day, so continued the next day.

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The next day the Master asked an officer to print out the alarm list for the ballast water management system, prior to arriving at the next port as a port state inspection would take place. To get the list the officer had to start the ballast water management system, which he did.

The bilge high level alarm was activated in the engine room. An oiler checked the bilges and could see water pouring in, covering the tank top. An engineer turned off the power to the ballast water management system.

He found that two ballast system valves were open from the main seawater crossover suction line. He closed these valves to stop the ingress of the water. These valves had been opened automatically when the ballast water management system started. The engineers pumped the water from the tank top into the bilge holding tank.

An hour later the M/E bearing wear alarm - Water Level 50%, went off. The lube oil for the crank case had 0.09% of water in it. The second lubricating oil purifier was started. A little later the M/E bearing wear alarm went off again. A second sample of the lube oil was taken, and it was found that the oil had 0.08% of water in it.

The chief engineer decided to partially change 3,000 litres of lubrication oil for the crank case. A third sample was taken and the water content was 0.019%.

Subsequently, the engine stopped and a full change of the lube oil was performed. A crosshead bearing was opened for inspection. No damage was found. Nevertheless, one of the rubber diaphragm seals for draining the crankcase to the system lubricating oil tank was found to be defective. This caused the water flooding into the engine room to contaminate the lube oil.

The main engine restarted and the voyage continued. The main engine was an electronic controlled model i.e. the exhaust valves and fuel injection system were powered by hydraulics. The system lubrication oil was also used as a hydraulic medium.

The next day there were problems with some hydraulic components and the main engine had to be stopped. A couple of cylinder units and pumps had to be dismantled, cleaned and reassembled. The main engine could not be restarted because of low hydraulic pressure. It was decided that one of the cylinders had to be blanked off.

The main engine was started and stopped numerous times the next days as the hydraulic system was leaking. Because the engine was running on low rpms, the scavenge trunking became fouled with oil deposits, so the engine had to be stopped several times and the trunking had to be cleaned.

Probable cause

A defective rubber diaphragm caused the water to flood into the engine room and contaminate the lube oil. Because of this, there was serious damage to crosshead bearings, crosshead pins, main engine cylinders, hydraulic pumps and main engine turbo charger bearings.