List of sunken nuclear submarines

See also: Nuclear submarine accidents

Eight nuclear submarines have sunk as a consequence of either accident or extensive damage: two from the United States Navy, four from the Soviet Navy, and two from the Russian Navy. Only three were lost with all hands: two from the United States Navy and one from the Russian Navy. All sank as a result of accident with the exception of K-27, which was scuttled in the Kara Sea when repair was deemed impossible and decommissioning too expensive. All of the Soviet/Russian submarines belonged to the Northern Fleet. Although the Soviet submarine K-129 (Golf II) carried nuclear ballistic missiles when it sank, it was a diesel-electric submarine and is not in the list below.

Of the 8 sinkings, 2 were due to fires, 2 were due to explosions of weapons systems, 1 was due to flooding, 1 was weather-related, and 1 was sunk intentionally due to a damaged nuclear reactor. In 1 case, the cause of sinking is unknown. All of the subs are in the Northern Hemisphere, and there are none in either the Indian or Pacific Oceans.

United States

 * Thresher (SSN-593), the first submarine in its class, sank April 10, 1963 during deep-diving trials after flooding, loss of propulsion, and an attempt to blow the emergency ballast tanks failed, causing it to exceed crush depth. All 129 men on board died. Location: 350 km east of Cape Cod.
 * Scorpion (SSN-589), a Skipjack-class submarine, sank May 22, 1968, evidently due to implosion upon reaching its crush depth. What caused the Scorpion to descend to its crush depth is not known. All 99 men on board died. Location: 740 km southwest of the Azores.

Soviet Union

 * K-27: The only Project 645 submarine, it was irreparably damaged by a reactor accident (control rod failure) on May 24, 1968. 9 were killed in the reactor accident. After shutting down the reactor and sealing the compartment, the Soviet Navy scuttled her in shallow water (108 ft) in the Kara Sea on September 6, 1982, contrary to the recommendation of the International Atomic Energy Agency (IAEA).
 * K-8: A Project 627 November class submarine was lost April 11, 1970 while being towed in rough seas following a fire on board. The submarine was initially evacuated, but 52 reembarked for the towing operation. All hands on board were lost (52), while 73 crewmen survived on the rescue vessel. Location: Bay of Biscay, 490 km northwest of Spain in the North Atlantic Ocean.
 * K-219: A Project 667A Yankee I class sub was damaged by a missile explosion October 3, 1986, then sank suddenly while being towed after all surviving crewmen had transferred off. 6 crew members were killed. Location: 950 km 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 5 crewmen evacuated prior to sinking. 42 perished, many from smoke inhalation and exposure to the cold waters of the Barents Sea. A total of 27 crew members survived.
 * Soviet submarine K-429 sank twice, but was raised after each incident.

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 Russian submarine Kursk explosion. All 118 men on board were lost. However, all except the extreme bow section was later salvaged.
 * K-159: The hulk of the decommissioned 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. 9 men perished in the accident.