Nine nuclear submarines have sunk, either by accident or scuttling. The Soviet Navy has lost five, the Russian Navy two, and the United States Navy two. Three were lost with all hands - the two from the United States Navy and one from the Russian Navy, and these are also the three largest losses of life in a submarine. All sank as a result of accident except for, which was scuttled in the Kara Sea when proper decommissioning was considered too expensive. The Soviet submarine carried nuclear ballistic missiles when it was lost with all hands, but as it was a diesel-electric submarine, it is not included in the list. The two USN submarines belonged to Submarine Force Atlantic, in the U.S. Atlantic Fleet. All five of the Soviet/Russian nuclear submarines that remain sunken belonged to the Northern Fleet, while the refloated was in the Pacific Fleet. Of the nine sinkings, two were caused by fires, two by weapon explosions, two by flooding, one by bad weather, and one by scuttling due to a damaged nuclear reactor. Only 's reason for sinking is unknown. Eight of the submarines are underwater wrecks in the Northern Hemisphere, five in the Atlantic Ocean and three in the Arctic Ocean. The ninth submarine, K-429, was raised and returned to active duty after both of her sinkings.
United States
, the first submarine in her class, sank April 10, 1963 during deep-diving trials after flooding, loss of propulsion, and a failed attempt to blow the emergency ballast tanks, causing it to exceed crush depth. All 129 on board died, including shipyard personnel supporting the deep-diving tests. Location: east of Cape Cod.
, a, sank May 22, 1968, evidently due to implosion upon reaching crush depth. The results of the U.S. Navy's various investigations into the loss of Scorpion are inconclusive. There are various theories about the loss. All 99 men on board died. Location: southwest of the Azores.
Soviet Union
: The only Project 645 submarine, K-27 was decommissioned in 1979 after many years of difficulty with its reactor. On September 6, 1982, the Soviet Navy scuttled it in shallow water in the Kara Sea after sealing the reactor compartment. This sinking in shallow water was contrary to the recommendation of the International Atomic Energy Agency.
: A Project 627 November-class submarine was lost on April 11, 1970 while being towed in rough seas after a fire on board. The submarine's crew was initially evacuated to a surface vessel, but 52 re-boarded the surfaced submarine for a towing operation. All 52 sailors died when the submarine flooded and sank, for total losses of 60 crew when counting the 8 who perished on April 8 in the initial fire. Location: Bay of Biscay, northwest of Spain in the North Atlantic Ocean.
: A Project 667A Yankee I-class sub was damaged by a fire in a missile tube and explosion on October 3, 1986. It then sank suddenly while being towed after all surviving crewmen had transferred off. Six crew members were killed. Location: east of Bermuda in the North Atlantic Ocean.
K-278 Komsomolets: The only Mike-class sub built sank due to a raging fire April 7, 1989. All but five crewmen evacuated before it sank. A total of 42 crew died, many from smoke inhalation and exposure to the cold waters of the Barents Sea, while 27 crew members survived.
: A Project 670A Charlie I-class sub sank twice, once at sea from flooding during a test dive, then two years later, from flooding at her moorings. Sixteen crew died in the first incident. K-429 was raised after both sinkings, and was decommissioned two years after the second.
Russia
K-141 Kursk: The Oscar II-class sub sank in the Barents Sea on August 12, 2000 after an explosion in the torpedo compartment. See Kursk submarine disaster. All 118 men on board were lost. All except the bow section was salvaged.
: Left to rust for 14 years after being decommissioned, this Soviet-era November-class submarine sank in the Barents Sea on August 28, 2003, when a storm ripped away the pontoons necessary to keep it afloat under tow. Nine of the 10 salvage men on board were killed.
General
C. Tingle, "Submarine Accidents: A 60-Year Statistical Assessment", Journal of Professional Safety, American Society of Safety Engineers, September, 2009, pages 31–39. Ordering full article: https://www.asse.org/professionalsafety/indexes/2009.php; or Reproduction less graphics/tables: http://www.allbusiness.com/government/government-bodies-offices-government/12939133-1.html.
