NTSB: Crew’s actions effectively contained fire on OSV near Hawaii

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(WASHINGTON ) — The National Transportation Safety Board (NTSB) issued Marine Accident Brief 21/26 on Wednesday, detailing its investigation of the diesel generator engine failure and subsequent fire aboard offshore supply vessel Ocean Intervention on Dec. 19, 2020, near Honolulu, Hawaii.

No pollution or injuries to the 16 crewmembers were reported in connection with the mechanical failure, which resulted in a fire in the engine room. The crew isolated the fire before it could spread throughout the vessel. Damage to Ocean Intervention totaled over $3 million.

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The yellow bracket identifies the damaged area of the main crankshaft of the No. 3 diesel generator (left) on Ocean Intervention, where the No. 1 connecting rod bearing failed (right). Oceaneering International photos

While at anchorage, the Ocean Intervention crew had been troubleshooting speed variation issues related to the No. 1 and No. 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 No. 3 diesel generator suffered catastrophic mechanical failure. This resulted in cylinder No. 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 NTSB determined the probable cause of the diesel generator engine failure 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.

“Engine rooms contain multiple fuel sources as well as mechanical ventilation, making the spaces especially vulnerable to rapidly spreading fires,” the report said. “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.”

– National Transportation Safety Board

By Professional Mariner Staff