HMS Superb struck Red Sea pinnacle after chart depth misread as 723m instead of 123m

Published Aug 16, 01:20 AM UTC

On May 26, 2008, the Royal Navy Swiftsure-class nuclear attack submarine HMS Superb struck a charted underwater pinnacle in the Red Sea south of Suez, leaving her unable to dive. Evidence presented at a court-martial revealed that a summit marked at 123 meters on the navigation chart was misread as 723 meters. Commander Steven Drysdale approved a transit at around 250 meters, believing the seabed was far below. The 5,000-ton submarine suffered damage to her bow and main sonar but no injuries or reactor damage occurred. The Ministry of Defence Board of Inquiry found no equipment failure; the accident resulted from a rushed plan, a misread depth, a four-mile shortcut, weak supervision, and poor watch handovers. The crew's response after impact was described as exemplary. The incident led to changes in Royal Navy navigation procedures.