Soviet submarine S - 80 S - 80 was a diesel - electric submarine of the Soviet Navy . Its keel was laid down on 13 March 1950 at Krasnoye Sormovo as a Project 613 unit ( NATO : ) . It was launched on 21 October , and delivered to Baku on the Caspian Sea on 1 November for tests , then transferred north via inland waterways in December . It was commissioned into the Northern Fleet on 2 December 1952 , and operated there until mid - 1957 . Beginning in July 1957 , " S - 80 " was overhauled at Severodvinsk and converted to Project 644 ( " Whiskey Twin - Cylinder " ) guided missile submarine , by having launch tubes for two SS - N - 3 Shaddock anti - ship missile s fitted externally . It returned to sea in April 1959 . Sinking . During the night of 26 January 1961 , " S - 80 " was operating in the Barents Sea at snorkel depth on its diesel engines . The ocean was at sea state 6 and air temperature was - 5 °C ( 23 °F ) . At 01 : 27 on 27 January , the boat dropped below snorkel depth , which should have caused the automatic snorkel valve to shut , preventing water from entering the snorkel system . However , the de - icing system that should have warmed the valve with hot water from the diesel engines had been switched off , and the valve had become jammed with ice . The diesel engines failed immediately as seawater flooded their air intakes . The machinist in the fifth compartment who discovered the flooding became confused by the complex array of valves , and did not shut the ventilation flapper valve quickly enough . By the time he located the correct handwheel , the valve spindle had been bent by the force of the flooding water . As the compartment filled , the boat ' s trim became uncontrollable . As its up - angle passed 45 degrees , the boat slowed , coming to a halt and then falling backward , gathering sternway and sinking until it grounded . The second , third , and fourth compartments were crushed , though 24 crewmen survived in the after compartments . Their attempts to escape the wrecked submarine using IDA - 51 apparatuses failed , and all 68 officers and men of " S - 80 " were lost . Their fate remained unknown for seven and a half years . Recovery . On 23 June 1968 , salvage vessel " Altai " discovered the wreck of a submarine at 70°01 ′ 23 ″ N 36°35 ′ 22 ″ E , at a depth of . The crew inspected the wreck with its bathyscape and identified it as " S - 80 " . A government commission studied the report and ordered Operation " Depth , " the salvage of the wreck . The Nikolayevsk SSZ shipyard built " Carpathia " , a special salvage vessel equipped to raise the sunken submarine . Operation " Depth " was carried out by a task force of the Northern Fleet consisting of groups of trawlers and a destroyer under the command of Captain First Rank S . Minchenko . The wreck was lifted from the ocean floor on 9 June 1969 and transported to Mys Teriberskiy , suspended under " Carpathia " in slings . There , it was lowered to the bottom of Zavalishin Harbor at a depth of on 12 July . On 24 July 1969 , " S - 80 " was raised to the surface . During August , a government commission began studying the wreck under the management of Hero of the Soviet Union Vice Admiral G . I . Schedrin . The commission determined not only the immediate causes of the boat ' s loss , but also that two further errors had compounded the accident : the crew never attempted to shift propulsion to the electric motors , and they never performed an emergency ballast tank blow .