MAIB releases report on near-miss between submarine, ferry in Irish Sea

The UK's Marine Accident Investigation Branch (MAIB) has released its investigation report into a marine accident in 2018 wherein a Royal Navy submarine and a commercial passenger vessel nearly collided in the North Channel of the Irish Sea between Belfast and Cairnryan in Scotland.

At 12:56 local time on November 6, 2018, an officer of the watch on the Stena Line Ro-Pax ferry Stena Superfast VII took urgent action to avoid a submerged submarine after its periscope had been spotted close ahead of the ferry (pictured).

Post-event analysis by both the MAIB and the Royal Navy showed that, prior to the ferry's course alteration, there had been a serious risk of collision.

The 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.

The MAIB report did not disclose the name of the submarine but confirmed that it is nuclear-powered and had been conducting an at-sea training exercise out of HM Naval Base Clyde in Faslane, Scotland, at the time of the incident.

The MAIB report added that the key similarity between this incident and two previous collisions involving Royal Navy submarines was the absence of a sufficiently accurate picture of surface shipping to support safety-critical decision-making.

In response to the near-miss, the Royal Navy reported that the following actions had been taken:

• Flag Officer Sea Training (FOST) shore-based simulator training was updated to enhance the management of close quarters situations with merchant or fishing vessels.
• Submarine command teams were briefed on the critical importance of operating safely at periscope depth in coastal waters. This included a brief on the facts of this case to raise awareness of the potential risks posed to submarines and other vessels nearby.
• Comprehensive learning from experience (LfE) events were delivered to submarine command teams prior to proceeding to sea.
• Training and documentation for the operational use of AIS was reviewed.
• FOST was amended to ensure that, if a close quarters procedure was commenced, this was run to conclusion and not interrupted.
• Incident reporting procedures have been reviewed and the amended policy reiterated to the submarine flotilla; commanding officers are also briefed on reporting requirements prior to taking command.
• The decision to conduct safety training in areas of known high density shipping was reviewed and found to be justified. However, direction was given that a formal risk assessment should be conducted by FOST prior to safety training commencing.
• All submarines operating near known shipping lanes and when operational circumstances permit, were recommended to use radar to provide increased accuracy of ranging.

The MAIB recommended that the Royal Navy deliver an independent review of the actions taken following this and previous similar events, to provide assurance that such actions have been effective in reducing the risk of collision between dived submarines and surface vessels to as low as reasonably practicable.

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