Narrowly avoiding disaster
Injuries and wider fire damage were only avoided during an engine room fire aboard a hybrid ferry thanks to “exceptionally favourable circumstances”.
Material fatigue aboard the hybrid ferry Berlin led to gear oil being sprayed into the engine room and onto hot surfaces, resulting in a fire. Despite a highly trained and well-drilled crew, a report by Germany’s Federal Bureau of Maritime Casualty Investigation (BSU) found that a number of errors were made in the extinguishing of the blaze.
Engine room alarm
The 22,319 gross ton Berlin has a hybrid propulsion system, comprising three medium speed diesels driving a controllable pitch (CP) propeller through a common gearbox, and a diesel electric system powering a pair of Azipull thrusters. The three diesels are arranged in a single engine room separated by a bulkhead from the diesel generator room.
At 2.45pm on 13 August 2020 the Berlin was approaching Rostock, Germany’s largest Baltic port, when alarms sounded in the engine control room and workshop. A mechanic acknowledged the workshop alarm and proceeded to the source of the main engine alarm. A leak was discovered from a double nipple on top of the gearbox. A second mechanic reached the scene and saw flames and smoke around one of the turbochargers.
A minute later, the main engine room smoke detector went off. However, the object protection system did not trigger automatically, as this only happens when two detectors are set off.
By 2.50pm, all main engines had been stopped, as well as the electric gear oil pump, while the gearbox was disengaged. The engine room watch then began manual firefighting using hand fire extinguishers. The general alarm was sounded from the bridge a minute later, and mustering of the crew and passengers began. At the same time, the bridge triggered the fuel supply quick-closing valves for the engines, preventing more fuel being added to the fire.
A distress call was sent to Warnemünde Vessel Traffic Services, stating that the fire was being fought and no assistance was required. The ship would continue to be fully manoeuvrable thanks to the hybrid electric drive, which was not affected in any way by the fire.
Fire hoses were laid out in the main engine room and a foam extinguisher was used in the turbocharger area. The object protection system was activated, and by 3.24pm the fire was out. The Berlin proceeded into Rostock on its diesel electric propulsion system, being alongside by 4.24pm.
The port of Rostock, which the Berlin safely made it back to (Credit: Shutterstock)
Tactical errors
The subsequent investigation identified the initial cause as the failure of the gearbox double nipple due to material fatigue. It found that vibration led to a fracture which, combined with the internal pressure, caused the failure. The leaking oil then impinged on several hot spots on the engines, causing the fire.
The report pointed out that thermographic checks carried out a year before had indicated several areas in the engine room where temperatures exceeded the permitted maximum of 220°C, some being almost 300°C.
Construction of medium speed engines is so “compact and delicate” that insulation is difficult, the BSU report said, and the fire caused partially burned insulation damage to the exhaust duct of one of the main engines.
The firefighting performance of the crew was also considered. Several systems were used, including foam and water fire extinguishers, Venturi jet pipe, and a low-pressure water spray.
Whilst there was good visibility in the engine room, the fire was only fought sporadically using foam hand fire extinguishers. This procedure was repeated several times, but it soon became clear that neither the effectiveness of the extinguishing agent nor its reach towards the source of the fire was sufficient to put it out.
The engine room watch continued firefighting without donning any protective clothing. Meanwhile, a water line and a foam line were set up and used, but no teams were formed to handle them.
“The firefighting measures were limited to individual actions without central supervision,” the report said. “A further tactical error was that the water-based object protection system was not activated manually immediately.”
Report recommendations
Despite the success fighting the fire, the report said that the approach adopted should be avoided where possible, to keep crew safe from harm. Only slight changes in the circumstances, which the engine room crew might not have been able to control, could have put those in the vicinity of the fire in sudden danger.
The visibility and temperature conditions were so good during the incident that the firefighters were neither hindered nor put at risk at any point. This was especially true of the unprotected engine room watch, who operated in the affected space throughout the entire incident.
As the report highlighted, “fires in engine rooms can never be completely avoided”. Personal injuries and much worse fire damage were only prevented by the “exceptional circumstances” during the incident.
It also pointed out that object protection systems should be arranged to give full coverage of the area, without any blind spots. Thermographic checks should also be carried out regularly to identify hot spots that could cause fires in future.
Read the full BSU investigation report into the fire in the Berlin engine room.
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John Barnes is a journalist and author and former editor of Marine Engineers Review.