The UK MAIB issued an investigation report on the catastrophic engine failure and subsequent fire on the 15-metre windfarm crew transfer vessel ‘Windcat 8’, off the Lincolnshire coast, UK, noting that the fixed firefighting system was operated, but it was ineffective because not all the engine space vents had been closed. The fire caused only minor damage and eventually extinguished when it ran out of fuel.
The incident
At 1620 on 7 September 2017, the crew transfer vessel ‘Windcat 8’, operated by Windcat Workboats, departed wind turbine LN09 on the Lynn Wind Farm to Grimsby, UK, with a master and a deckhand onboard. As Windcat 8 cleared the windfarm, the master increased the vessel’s speed to 21 knots. At 1638, a high engine oil temperature alarm activated on the port engine indication panel on the forward console in the main cabin.
The master immediately set both engines to idle and told the deckhand to go to the port engine space to investigate. The deckhand checked the port engine’s cooling system and oil level but he did not identify anything unusual. He returned to the cabin, closing the port engine space deck hatch behind him, and reported his findings to the master. As the high oil temperature alarm on the indication panel had now reset, the master decided to resume passage. At 1640, he increased the vessel’s speed back to 21 knots and monitored the port engine temperature, which remained normal.
At 1646, there was a loud bang in the port engine space, the port engine stopped, and the port engine space fire alarm activated. The master saw from the closed-circuit television (CCTV) monitor that the port engine was alight. In response, he stopped the starboard engine, shouted that there was a fire, instructed the deckhand to close down the port engine space and activate its fire extinguishing system. He also stopped the ventilation fans servicing the port engine space and told the eight technicians to prepare for evacuation.
The deckhand went onto the aft deck and closed the flap on the port engine space supply vent. He then activated the port engine space’s fire extinguishing system using controls located on the cabin’s aft bulkhead, behind the last row of seats. By 1648, the port engine space was filled with the extinguishing medium, which obscured the fire on the CCTV monitor and a white gaseous cloud billowed from the port engine space’s natural air vent on the aft deck and into the cabin through its open door. The technicians left the cabin and mustered on the foredeck. At 1649, the master broadcast a “Mayday” using VHF on channel 16. Windcat 30 and Windcat 31, also owned by Windcat Workboats, were nearby and closed to assist.
At 1650, the deckhand supervised the transfer of the technicians from Windcat 8 to Windcat 31. He then returned to the aft deck, where plumes of dark smoke were now coming from the port engine space’s natural vent and entering the cabin through its open door. He leaned through the smoke and operated the remote fuel shut- off for the port engine sited next to the vent. The master then sealed the natural and exhaust vents.
By 1653, the smoke had cleared from the port engine space and flames were observed burning along the top of the port engine. Four minutes later the port engine was again obscured by smoke. Meanwhile, the master and the deckhand rigged a fire hose on the aft deck in readiness for boundary cooling. The remote fuel shut-off for the starboard engine was also operated.
At 1700, the fire appeared to be out and Windcat 8 was taken in tow by Windcat 30 for passage to Grimsby. The master referred to the vessel’s emergency checklists and later re-started the starboard engine to expedite the transit. The vessels arrived at Grimsby Fish Dock at 2100 and were met by local personnel, who confirmed that the fire had been extinguished.
Probable cause
The MAIB investigation identified that the catastrophic damage to Windcat 8’s port main engine was caused by the failure of a piston connecting rod big end shell bearing, which resulted in the connecting rod assembly releasing and penetrating through the engine crankcase.
Conclusions
- The initial high oil temperature alarm prior to the engine failure warranted a more cautious approach until a deeper technical investigation could be conducted
- The fire resulted from the ignition of oil vapour released from the damaged engine
- The fixed fire-fighting system was rendered ineffective because not all the port engine space vents were closed prior to its activation
- The safety of the embarked technicians was given a high priority
Recommendation
The vessel’s operator has been recommended to provide training and guidance to its crew on actions to be taken in the event of critical propulsion alarms, and to ensure they are familiar with the use of fixed fire-fighting systems.
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