On 19th April 1994 the New Zealand flag ro-ro vessel Union Rotoma was on passage from Nelson in New Zealand to Port Botany in NSW when, at 1835, alarms were sounded by the vessel's automatic fire detection system indicating a fire in the engine room. The duty engineer quickly reported that the aft end of the port main engine was on fire. The fire was spreading very rapidly and the decision was taken to evacuate the engine room and to flood it with the ship's fixed carbon dioxide extinguishing system. A "Mayday" message was transmitted by Inmarsat C and was acknowledged by the Maritime Rescue Coordination Centre in Canberra.
While the crew were shutting down the engine room, the bulk COČ was released. The main engines had been stopped from the bridge. Shortly after the release, the running generator stopped, indicating that it had been stifled by the COČ. Approximately one and a half hours after the release of COČ, two engineers wearing breathing apparatus made an inspection of the engine room and reported that the fire had been extinguished and there were no remaining hot spots.
The engine room was purged of COČ before a further inspection was made and the generators were started to restore full electrical power. The inspection revealed that oil, spraying from a fractured pipe on the starboard engine, had ignited on the hot exhaust manifolds of the port engine. The pipe, carrying lubricating oil to the engine's overspeed trip mechanism and to the camshaft bearings, had been fractured by the movement of the camshaft anchor bearing housing moving out of the entablature, into which it had been secured by eight 20mm diameter set bolts, all of which had sheared or worked loose.
Damage caused by the fire was slight, involving mainly instrumentation and wiring. The ship was able to proceed on its voyage to Port Botany using only the port main engine.
The incident was investigated by the Marine Incident Investigation Unit under the provisions of the Navigation (Marine Casualty) Regulations.
These conclusions identify the different factors contributing to the accident and should not be read as apportioning blame or liability to any particular organisation or individual.