The National Transportation Safety Board issued an investigation report focusing on the diesel generator engine failure of the offshore supply vessel Ocean Intervention on Dec. 19, 2020, near Honolulu, Hawaii.
The incident
At 1303 local time on December 19, 2020, the no. 3 diesel generator engine aboard the Ocean Intervention suffered a mechanical failure while the offshore supply vessel was anchored off Honolulu, Hawaii.
In fact, while at anchorage, the Ocean Intervention crew had been troubleshooting speed variation issues related to the number 1 and number 3 diesel generator engines, which involved replacement and calibration of several electrical components and multiple engine restarts.
When later carrying the vessel’s electrical load, the number 3 diesel generator suffered catastrophic mechanical failure. This resulted in cylinder number 1’s connecting rod being ejected through the engine crankcase while running at rated speed.
The ejection of the connecting rod allowed atomized oil to be released from the engine and ignite, starting a fire in the engine room. The crew’s quick and effective actions to prevent the spread of the fire resulted in the fire extinguishing itself without putting crewmembers at risk.
The failure led to the ejection of components from the engine and resulted in a fire in the engine room. The crew isolated the fire before it could spread throughout the vessel. No pollution or injury to the 16 crewmembers on board was reported. Damage to the Ocean Intervention totaled $3,046,624.
Findings
The National Transportation Safety Board determines that the probable cause of the diesel generator engine failure aboard the offshore supply vessel Ocean Intervention was a cylinder’s connecting rod bearing adhering to the crankshaft, which led to the ejection of the connecting rod and catastrophic damage to the engine.
Lessons learned
- Engine rooms contain multiple fuel sources as well as mechanical ventilation, making the spaces especially vulnerable to rapidly spreading fires.
- The crew of the Ocean Intervention effectively contained the spread of a fire by removing fuel and oxygen sources.
- Vessel crews should familiarize themselves and train frequently on machinery, fuel oil, lube oil, and ventilation shutoff systems to quickly act to contain and suppress engine room fires before they can spread to other spaces and/or cause a loss of propulsion and electrical power.
