The Marine Accident Investigation Branch have published a report on a 2018 near miss between a Royal Navy submarine and a passenger ferry.
The near miss between a Stena passenger ferry and a Vanguard class submarine occured in 2018.
It should be noted that while Vanguard class submarines carry Trident nuclear missiles, the submarine involved was undertaking pre deployment training and was likely not armed with nuclear weapons.
At 1256 on the 6th of November 2018, Stena Superfast VII’s officer of the watch took urgent action to avoid a Vanguard class nuclear submarine after its periscope had been spotted close ahead of the ferry.
The report states that post-event analysis showed that, prior to the ferry’s course alteration, there had been a serious risk of collision. 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.
The MAIB say that 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.”
Statement from the Chief Inspector of Marine Accidents
“On 6 November 2018, the lookout on board the ferry Stena Superfast VII spotted a submarine’s periscope close ahead. The officer of the watch then took immediate and effective action, turning the ferry to avoid a genuine risk of collision with a submerged submarine. The incident happened because the submarine’s control room team had underestimated the ferry’s speed and overestimated its range, resulting in safety-critical decisions being made based on inaccurate information.
Although there was no collision, this was the third accident or incident between a dived Royal Navy submarine and a surface vessel in 4 years, which is a matter of significant concern. The Royal Navy co-operated with the MAIB’s investigation into this near miss and has taken a series of actions, intended to prevent recurrence, in response to this, and the other similar incidents. However, I have today recommended that the Royal Navy undertakes an independent review of the actions that have been taken, in order to ensure that the risk of similar collisions has been reduced to as low as possible.”