At 12 noon, January 8 2005, Guam Time, the USS San Francisco, SSN-711, hit an uncharted undersea mountain while traveling at high speed about 500 ft below surface.
On 12 August 2000, the Russian Oscar II class submarine Kursk sank in the Barents Sea. The generally accepted theory is that a leak of hydrogen peroxide in the forward torpedo room led to the detonation of a torpedo warhead, which in turn triggered the explosion of up to seven other warheads about two minutes later.
HMCS Chicoutimi is a Victoria-class long-range patrol submarine of the Canadian Forces Maritime Command. Shortly after being handed over from Britain to Canada she suffered a fire at sea, which sparked a fierce debate over the value of the purchase of this group of second-hand vessels, as well as the handover inspection process.
Russian submarine Juliett 484 sank on April 18, 2007 after a storm in Providence Rhode Island harbor where it was on static display.