StenaSuperfastVII Submarine PeriscopeAsSeenFromFerry

Near miss between a ro-ro ferry and a submerged submarine in the North Channel between Belfast, Northern Ireland and Cairnryan, Scotland.

Our accident investigation report into the near miss between the ferry Stena Superfast VII and a submerged Royal Navy submarine on 6 November 2018, is now published.

At 1256 on 6 November 2018, Stena Superfast VII’s officer of the watch took urgent action to avoid a submerged submarine after its periscope had been spotted close ahead of the ferry. Post-event analysis showed that, prior to the ferry’s course alteration, there had been a serious risk of collision.
(NOTE: In photo above periscope can be seen on the left)

This near miss happened because the submarine’s control room team had underestimated the ferry’s speed and overestimated its range, resulting in an unsafe situation developing. However, the submarine’s control room electronic tactical display presented a picture of a safer situation than reality; this meant that safety-critical decisions made on board the submarine may have appeared rational at the time.

Safety Issues
• safety-critical decisions need to be made based on accurate information
• passage planning should identify all potential hazards and effective mitigations
• maintaining a good lookout is vital for the safety of all vessels

The Royal Navy has taken a series of actions in response to this and similar previous accidents. As a result, a safety recommendation (2020/124) has been made to the Royal Navy to undertake an independent review to ensure that the actions taken have been effective in reducing the risk of further collision.

Source: MAIB