The "Thetis" accident happened after the inner hatch on a torpedo tube was opened while the outer hatch to the sea was also open. Four men successfully used the sub's one-man escape chamber before a fifth panicked and jammed it. A total of 99 men lost their lives as a result. The sinking led to the redesign of all torpedo tubes on British and Australian submarines. A latch, known as the ""Thetis" clip", was added to the inner torpedo tube door so it could be fractionally opened to check the tube was not open to the sea before being fully opened.