On 28 October 2013 – Report No 12/2014
UK Marine Accident Investigation Brach (MAIB) has issued report No. 12/2014 on the investigation of the anchor dragging and subsequent grounding ofSTENA ALEGRA.
According to the report at 18:51 (UTC1 +1) on 28 October 2013, the RoPax ferry Stena Alegra grounded after dragging its anchor in 76 knot winds off Karlskrona, Sweden.
The vessels bottom plating and frames were damaged, and one ballast tank and one void space were flooded. Two tugs towed the vessel off the rocks after the weather had moderated the next day. Following an underwater inspection the vessel proceeded to Gdynia, Poland, for repair.
The MAIB investigation identified that the master had decided to anchor the vessel in winds that were forecast to increase to the assumed maximum design limit of its anchoring equipment without completing a full assessment of the consequent risks.
The wind speed rose to above that forecast, causing the vessel to drag its anchor. Measures aimed at arresting the vessels drift failed to prevent Stena Alegra from running aground.
Recommendations have been made to the vessels manager, Northern Marine Management Ltd, to enhance its safety management system requirements for anchoring, including contingency planning, and the enhancement of masters handover procedures.
| Conclusions |
- The master decided to anchor Stena Alegra with wind conditions forecast to increase to the assumed design limitation of its anchoring equipment. In doing so, he did not take into account the additional loading that would be caused by the vessel yawing, and did not consider contingency options should the wind speed increase to beyond that forecast.
- In dismissing an option of proceeding to sea, the master did not consider steaming a short distance along the coast and to then heave to in areas where the sea conditions were likely to have been more favourable. He might also have misinterpreted the Sea State Restriction of 4 metres listed on the vessels Operational Limits certificate.
- The masters decision to anchor was influenced by his previous successful, albeit limited, experience of anchoring other Ro-Ro and RoPax vessels in winds of about 40 knots. He lacked familiarity with Stena Alegras capabilities and performance when anchored due to his limited time on the vessel and a lack of available guidance on board.
- The master did not construct a swinging circle for the vessel. Had he done so, he might have been alerted to the vessels close proximity to danger and the limited time that he would have available to arrest its drift should it start to drag its anchor.
- Had the master prepared a contingency plan to respond to changes in observed wind conditions rather than waiting for the vessel to drag its anchor, he could have taken proactive measures to prevent the grounding.
- The master lacked an appreciation of the vessels likely rate of drift should it start to drag anchor in the prevailing wind conditions. His expectation for No 3 main engine to be clutched in immediately if the vessel dragged its anchor was not effectively communicated to the engine control room. However, if No 3 main engine had been clutched in immediately, it is uncertain that its sole use would have prevented the vessel from grounding.
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More details may be found by reading the UK MAIB Investigation Report
