Report on the investigation of the near miss between the ro-ro ferry Stena Superfast VII and a submerged Royal Navy submarine in the North Channelon 6 November 2018
MARINE INCIDENT REPORT NO 13/2020 JULY 2020
SECTION 3– CONCLUSIONS
3 .1 SAFETY ISSUES DIRECTLY CONTRIBUTING TO THE INCIDENT THAT HAVE BEEN ADDRESSED OR RESULTED IN RECOMMENDATIONS
1.Until avoiding action was taken by Stena Superfast VII’s OOW, there was a serious risk of collision between a laden ferry and a submerged Royal Navy submarine. [2.3.4]
2.Stena Superfast VII passed inside the submarine’s go-deep range, therefore, it was unsafe for the submarine to remain at periscope depth. [2.3.3]
3.It was extremely fortunate that Stena Superfast VII’s bridge AB spotted the submarine’s periscope, though there was no reasonable expectation he would do so. [2.3.4]
4.Safety-critical decisions on board the submarine, specifically to turn towards the ferry and remaining at periscope depth, were taken based on inaccurate information. [2.3.1, 2.3.3]
5.Overestimation of the ferry’s range and underestimation of its speed resulted in the submarine’s command system presenting an inaccurate surface picture. However, this situation meant that the unsafe decisions might have seemed rational at the time. [2.3.3]
6.The submarine’s command team and the command qualified FOST sea rider demonstrated a bias towards the safer SMCS track that was based upon visual overestimations of the ferry’s range. This bias created a situation where other clues to the close proximity of the ferry could be ignored. [2.3.3] [2.4.2]
7.Perceived pressure to remain at periscope depth for training purposes might also have influenced the decision not to go deep. [2.3.3]
8.Although the submarine’s passage plan had identified the North Channel ferry hazard and the commanding officer had directed the OOW to remain south of the ferry lanes, the submarine was actually operating in the hazardous area. [2.4.1]
3.2 OTHER SAFETY ISSUES NOT DIRECTLY CONTRIBUTING TO THE INCIDENT THAT HAVE BEEN ADDRESSED OR RESULTED IN RECOMMENDATIONS
1.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. [2.4.3]
2.Although intended to provide assurance of safe operations, the embarked FOST command sea rider did not advise or intervene to ensure the safety of the submarine. [2.4.2]
SECTION 4– ACTION TAKEN
4 .1 ROYAL NAVY ACTIONS
4 .1.1 Actions in response to this incidentPost this incident the RN reported that the following actions had been taken:
●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 training 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.