In an accident report, the US National Transportation Safety Board (NTSB) found that debris in an engine’s lubrication oil system caused a serious engine failure and subsequent fire on board the passenger vessel ‘Ocean Navigator’, while she was berthed at Portland, Maine.
This incident occurred on 18th October, 2023, when the vessel’s No 2 auxiliary diesel generator engine experienced a catastrophic mechanical failure, which resulted in serious injuries to one crew member and an engine room fire.
At the time, she had 128 passengers on board, sustained an estimated $2.4 mill in damage. Fortunately, no passengers were injured, and no pollution was reported in the incident.
NTSB’s investigation revealed significant maintenance oversights.
For example, the vessel’s crew had operated the engine for more than 5,000 hours without changing the lube oil – five times longer than the manufacturer’s recommended interval.
The last complete lube oil change was performed in September, 2022, about 13 months before the failure.
In addition, the oil filter elements, which should have been replaced after 1,000 hours of operation, had been in use for over 3,000 hours since their last replacement in May, 2023.
An inspection by third-party technicians after the incident found extensive damage to critical engine components, including the crankshaft, main bearings, connecting rod bearings, and the No 14 fuel injector.
Further examination revealed abnormal wear on various bearings, showing signs of cavitation erosion and debris-related damage.
NTSB’s report concluded that the engine failure resulted from debris accumulation in the engine’s lube oil system, attributing this to the crew’s failure to follow manufacturer-recommended maintenance intervals.
The contaminated oil system led to catastrophic mechanical damage and ultimately caused the fire when atomised lube oil ignited after being released through the engine’s ruptured crankcase.
Despite the serious nature of the incident, the crew’s quick response prevented the situation from escalating. By promptly securing engine room ventilation and fuel sources, they successfully contained the fire, which self-extinguished.
In its report, the NTSB emphasised the importance of following manufacturer maintenance schedules, saying, “Manufacturers provide maintenance recommendations and intervals to ensure equipment operates safely, optimally, and reliably throughout its service life.”
The Board also highlighted the particular vulnerability of engine rooms to rapidly spreading fires, due to multiple fuel sources and mechanical ventilation.
It stressed the importance of crew familiarity with machinery, fuel oil, lube oil, and ventilation shutoff systems to effectively contain and suppress engine room fires.
