M2013-06 M/S AMORELLA (FIN), electrical disturbance leading into the grounding in the archipelago sea in Finland 14 December 2013

On the 14th of December 2013, at 8:45 in the morning, M/S AMORELLA left for its scheduled route from Turku to Stockholm via Mariehamn. Soon after passing Sandö, at about 12:33, when turning towards the narrow Hjulgrund passage in the Åland archipelago, a disturbance in the electrical system onboard caused a loss of the ship's maneuverability. Despite activation of the emergency steering system and emergency anchoring, the ship ran aground and got a leak in the forepeak. The vessel advised the Marine Rescue Coordination Centre (MRCC), which alerted vessels and aircrafts to the scene. The MRCC further ordered the Search and Rescue Sub-Region Management Board on the Åland Islands, a group composed of representatives for authorities and voluntary organizations, to prepare for a possible evacuation. The shipping company ordered a tug and divers. After damage inspections the vessel was allowed to continue to Mariehamn. The incident caused no injuries, no damage to cargo or the environment. The vessel was docked in Rauma and returned to service 12/20/2013.

The grounding was caused by a chain of events which occurred and culminated in a narrow part of the route. When performing maintenance work on the fuel pre-heater system for the auxiliary engines on the 14th of December, an error occurred when handling the valves of the fuel system. As a result of the handling mistake fuel began to leak out from an open viscometer flange in the fuel system. The flange had been left open the previous evening when maintenance work on the viscometer was discontinued. The flange had not been blinded, nor had the valves been locked. New maintenance work had been started in the same system without first finishing the uncompleted work. Handling the valves after the leakage interfered with the fuel system of the auxiliary engines to such an extent that the auxiliary generators disconnected from the electrical network causing an electrical disturbance. The main engines and propellers stopped and the steering gear on the navigating bridge stopped working. The fact that the power failure occurred at this section of the route was due to the fact that the maintenance instructions contained no warning or restriction regarding carrying out maintenance work in this, from a maneuvering point of view, critical part of the route. The duration of the power failure was longer than usual and the ability to maneuver was lost almost entirely for about 4 minutes. This time was too long for safe maneuvering of the ship in a narrow part of the fairway.

With respect to the bridge the safety investigation revealed that only this accident brought to daylight wiring faults in the electrical equipment that for many years had been hidden. These faults disturbed controlling the situation. For the bridge crew the maneuvering possibilities in the narrow passage were in practice non-existent since neither the propellers nor the steering gear, with the exception of an extra emergency steering system, were operational. The power failure lasted so long that the main engines and propellers were not operational again until the moment the vessel grounded. The PA-system was switched off when the electrical disturbance began and had to be re-started.

M2013-06 Report, in Finnish (pdf, 5.93 Mt)