The Marine Accident Investigation Branch (MAIB) said many of the routines on the Seatruck Ferries vessel were lax and communication was poor, partly due to a language barrier.
The 5,800-gt ship was shifting from a lay-by berth to the ferry linkspan at Warrenpoint in June last year when it suffered a total blackout.
There were no injuries, but the vessel suffered severe distortion of the port and starboard rudder stocks.
The MAIB said that just before it left the quay the port generator high freshwater temperature alarm sounded.
“The second engineer was working under pressure and unsupervised during the critical time of preparing to leave the berth. He was unable to determine the cause of the alarm and did not alert the chief engineer or master to the problem,” the report found.
The starboard generator alarm then also went off and a total blackout occurred.
The controllable pitch propellers defaulted to the full astern position and Moondance grounded.
After that, the chief engineer arrived in the engine room and shut down the main engines without approval from the bridge
The report said: “The situation in the engine room was chaotic. The chief engineer had difficulty establishing his authority because the Polish engineers discussed fault-finding options, in Polish, without consulting him.”
The problems were exacerbated because there was no lighting, it added.
The MAIB found that the emergency generator had failed to start automatically because it had been left in hand control. This was due to a long-standing defect that the chief engineer was unaware of.
The investigation also concluded that the high generator temperature was due to the isolating valve for the sea water cooling system, supplying the generators, being left shut or being only partially opened during the system reconfiguration for departure.
The move from the lay-by berth to the linkspan was considered by senior staff on board the vessel to be a routine operation.
“Complacency led to insufficient manning levels on the bridge and in the engine room, which contributed to the accident.”