HMCS Corner Brook ran aground in 45 metres of water at 10:45 a.m. local time (PST) on June 4, 2011, while conducting Submarine Officer Continuation Training in Nootka Sound off the West coast of Vancouver Island. The grounding occurred when the submarine struck the south eastern wall of Zuciarte Channel as a result of the submarine being south east of the intended position.
A military Board of Inquiry (BOI) was convened on June 10, 2011. The intent of the BOI was to investigate the cause and contributing factors that may have led to the grounding of Corner Brook and to identify applicable preventative measures, if any.
The BOI completed its initial inquiry after which the president and members of the board signed their report and passed it to the Convening Authority, Vice-Admiral Paul Maddison, Commander Royal Canadian Navy (RCN), on July 14, 2011. The convening authority requested additional clarifications on the report before approving on December 14, 2011.
The BOI was composed of Canadian Forces personnel consisting of a President and four members. The Board was supported by Legal Officers, a technical advisor and administrative support staff.
The members and advisors established their offices at CFB Esquimalt on June 10, 2011, and operated primarily at the Naval Officer Training Centre Venture and the Pacific Region Cadet Headquarters. Fifteen witnesses were subsequently summoned to testify before the Board from June 14 to 24, 2011. Further gathering of evidence, analysis and report drafting took place from June 25 to July 8, 2011. The BOI was re-opened at CFB Halifax from October 11 to 13, 2011, as directed by Commander RCN, to provide additional clarification to some of the findings, and to address several evidentiary observations resulting from a legal review of the report by the Deputy Judge Advocate General (DJAG).
Cause of Grounding
Human error was the key contributing factor to the grounding of HMCS Corner Brook on June 4, 2011. The Board found that the technical and materiel readiness of HMCS Corner Brook’s systems did not contribute to the incident.
The grounding was caused by a failure to properly account for the positional uncertainty of the submarine in accordance with approved dived submarine navigational practices and techniques when operating in confined waters.
Due to the lack of an external source to determine its position when deep, a dived submarine must navigate in a fundamentally different way than a surface ship. As such, a dived submarine must estimate its position over time, and account for possible errors. A graphical indication of where the submarine could potentially be, based on those possible errors, is used to navigate. This is called a “Pool of Errors” (POE) and is the authorized method of navigation for dived Royal Canadian Navy (RCN) submarines.
Simply put, submariners navigate by estimating the position of the submarine using various methods including GPS, visual bearings with the periscope, and soundings of ocean contours. Due to the fact that submarines operate submerged for extended periods, submariners apply a buffer zone around their estimated position, referred to as the POE. The POE takes into account errors in the submarine’s fix, gyro, speed log, and expected tidal and current information. Submariners carefully monitor the POE, which expands over time, and continuously strive to reduce it by using the navigational methods mentioned above.
A general lack of knowledge of the submarine electronic navigation system coupled with insufficient analysis of the risk associated with conducting dived operations in Nootka Sound were key factors contributing to the incident.
Action taken by Convening Authority
After careful review of the BOI findings, the Commanding Officer of HMCS Corner Brook was removed from Command and reassigned to a shore position. The decision to remove an individual from command is not taken lightly and is done through the application of a fair and comprehensive procedure. Typically, a loss of confidence in an individual’s ability to exercise sound judgment results in their removal from command.
In all, the Board made 19 recommendations, which included changes to the training system, amendments to training manuals, as well as changes to navigation planning practices. All recommendations were accepted by the convening authority, and all will be implemented as soon as practicable. The majority of the Board’s recommendations were related to submarine navigation training as well as supporting policies and documents. The RCN is fully committed to implementing the Board’s recommendations, drawing on the invaluable lessons learned from this incident to prevent a similar occurrence as the Victoria-class fleet nears full operational capability.
Updated: 16 December 2011