|None/ Major Engine Damage
The vessel was sailing in good weather. There was a high lube oil temperature alarm during the UMS (Unmanned Machinery Space) period. This alarm triggered a slow down and then a shutdown of the main engine. As a preliminary investigation, the lube oil cooler and the coolant temperature was checked on the local temperature gauges. The engineer on watch reported that there was an abnormal level in the sump tank and the cooling water expansion tank had lost water.
Cooling water had got into the lubricating oil sump and contaminated the lube oil system. It was further found that the number 2 cylinder head was leaking coolant from a loosened guide bolt on the inlet valve crossbar. Attempts to tighten the bolt failed. The cylinder head was replaced with a spare.
Approximately 900 litres of fresh oil was filled without draining off any contaminated oil. The main engine was restarted and the voyage resumed. Two days later when the vessel was approaching the pilot station, an alarm sounded indicating a high lube oil temperature from cylinder number 3 as per reports.
The engine was stopped and investigations were carried out. The investigation by the crew didn’t reveal any abnormalities and the engine was restarted. Shortly after the pilot embarked, the crankcase oil mist alarm was triggered followed by a banging noise from the engine and the engine automatically shut down. A tug provided assistance and the vessel anchored. A couple of hours later it was decided that the vessel should be berthed with tug assistance.
The number 3 cylinder unit had suffered piston seizure. Further damage was noted to the number 3 big-end bearing and crankpin journal, caused by the contaminated lube oil.
An analysis of the lubricating oil taken three months earlier for the main engine, showed that the oil was within specification. Another oil sample was taken one month before the incident and the analysis at this time showed a water content of 0.17%.
- UMS rounds are exclusively for inspection/checks to b e performed on the machinery running parameters rather not to perform any work/maintenance.
- The leaking cooling water was not spotted during the UMS rounds.
- The Expansion tank water level drop was not investigated, rather was just topped up to maximum level.
- Upon identification of lube oil contamination, the entire charge should have been replaced or at least partially replenished with fresh charge of oil.
- Lubricating oil purifier efficiency was poor that it merely pumped oil and did not remove any contaminants. It is recommended to get the Lubricating oil purifier efficiency checked by sending before and after purifier samples to Viswa Lab. By this, one can ensure and be ascertained that the lube oil purifier is performing well and thus it can remove water effectively when operated continuously.
- The High temperature or for that case, any alarms related to main engine lube oil system should be taken as Critical and all possible checks has to be done.
- Engine room should be “Manned” in such cases where continuous monitoring of machinery and its parameters are essential.
- Follow SMS (Safety Management System) guidelines or refer to engine maker’s manual for further actions.
- If heavy contamination of water is present in the system:
- the lube oil in the sump tank must be transferred to a settling tank.
- the sump tank should be cleaned.
- fresh oil filled to the minimum level recommended by the engine maker.
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