The Maritime Accident Investigation Branch (MAIB) have today (Thursday) published a report into the catastrophic engine failure on board Wightlink’s Wight Sky car ferry, which resulted in a fire and serious injuries to a crew member who was ‘engulfed in a ball of fire and experienced intense pain’.
At 21:33 on 12th September last year, whilst approaching Yarmouth, the car ferry suffered a failure of one of its main propulsion engines, followed by a fire. The fire was brought under control in less than 2 minutes but the vessel’s engineer, who had been standing near the engine, suffered serious burn injuries to his hands and face.
It has been concluded that the most probable trigger for the engine failure was debris in the engine’s oil channels following a rebuild, possible due to parts of the engine being transported through an emergency escape rather than through ‘soft patches’ (large openings in the deck to allow machinery to be moved around). The soft patches were not used to move the engines in or out of the engine rooms due to the disruption their removal would cause.
Although the source of any debris that might have entered the oil channels cannot be known for certain, debris could have entered the engine’s oil channels during the 3 days that the partially assembled engine had been exposed to the elements with only a loose plastic sheet for protection.
The engine failed after just 5-and-a-half hours of operation. However, the report highlights that it is not the first time the engine had failed. In July 2017, the same engine developed a coolant loss problem. The cause was not diagnosed but several cooled components, including the turbocharger and associated exhaust piping, were replaced. The problem persisted.
On 4th August, just over a month before the main incident, the cylinder head was replaced but on testing the engine thick white smoke was observed at the engine exhaust. On 11th August, the turbocharger was replaced but when the engine was run up one of the two exhaust valves on cylinder unit 5 sheared, resulting in the lower half becoming embedded in the piston. The failure was not investigated but was attributed to incorrectly adjusted valve tappet clearances. A full-rebuild was ordered.
Furthermore, the MAIB have found that the power supply to the essential services switchboard, which distributed power to critical equipment including water-mist fire suppression system, watertight doors, rescue boat davit, main hydraulic power pack and emergency lighting, was lost 27 minutes after the accident as the aft circuit breaker had been left in manual mode.
The MAIB say that the Hi-fog system was very effective in extinguishing the fire within a minute of having been activated. However, had the changeover from the port switchboard to the aft switchboard taken place immediately after the accident, not at 22:00, the Hi-fog system would have provided further protection for only 60 seconds, increasing the potential for re-ignition and growth of the fire. There were several fuelled vehicles parked on the deck directly abovethe forward machinery space, so the consequences of the loss of electrical power to the ES switchboard could have been very serious.
At the time of the incident there were 40 people on board Wightlink’s Wight Sky.
It has been confirmed that although he was discharged from hospital 7 days later, the injured engineer was subsequently diagnosed with post-traumatic stress disorder and has not returned to work.
In conclusion, the MAIB have said:
“The master was faced with a very difficult situation and, in co-ordination with the bosun, executed a series of quick actions that ensured the safety of the vessel, passengers and crew.
“The engineer was extremely fortunate that his injuries were not life threatening. The shrapnel ejected from the engine during the explosion thankfully missed him and, despite being engulfed in fire, his cotton boiler suit protected most of his body from the heat.
“Rebuilding the engine in a clean and controlled environment and transferring it complete into the engine room would have reduced the likelihood of debris ingress.
“The consequences of this accident could have been far worse”.
Actions have been taken by the vessel’s owner, Wightlink Limited, and by Volvo Penta UK, to address some of the issues identified in this report.
Wightlink have agreed that all engines will be fully assembled and load-tested prior to delivery on board and signage will be put in place to ensure that the circuit breakers for the essential services switchboard are correctly set at all times.
Volvo Penta have written to all dealerships to advise that, where appropriate, soft patches are removed to allow removal and reinstallation of complete engines. They have also advised that engine assembly is completed in a clean environment to prevent debris being built into an engine.
It has been recommended that Volvo Penta consider offering wear particle detection technology for Volvo Penta marine engines that cannot be easily serviced on board.
Report and photographs are Crown Copyright, obtained through the Maritime Accident Investigation Branch report dated July 2018.