When the Viking Sky suffered an engine-shutdown in March that nearly led to a grounding in stormy weather, it only carried 28 to 40 percent of lube oil in its engines, far less than the 68 to 70 percent recommended by the engine manufacturer, according to a preliminary report issued by the Norwegian Accident Investigation Board.

Thus, the engines shut down as a result of the loss of lubrication due to low sump tank levels, combined with the pitching and rolling of the ship, the report stated.

All three main engines shut down within 19 minutes of each other, causing a blackout and loss of propulsion.

The board also estimated that the Viking Sky came within a ship’s length of grounding, before propulsion was re-established.

Shortly after the incident Wilhelmsen Ship Management, which is responsible for Viking Ocean’s marine operations, issued a safety bulletin. They also identified several actions to be taken, including reviewing the management of appropriate lube oil levels, how to prepare for heavy weather and blackout recovery procedures.

According to the board, in cooperation with its class society, Wilhelmsen is also establishing procedures for sailing with one engine inoperative while maintaining compliance with the Safe Return to Port requirements.

The safety investigation of the Viking Sky incident is continuing, focusing on engine room alarm management, passage planning, decision support, lubrication oil management, evacuation and life saving appliances, safety management, local weather conditions and Safe Return to Port.