While trying to snorkel in state 6 seas (wave height 13-20-feet) in the southcentral Barents Sea, a W Class Soviet diesel submarine experienced severe flooding through the snorkel intake that killed the engine. The submarine sank to the bottom at a depth of 643-feet.

Three compartments collapsed upon inpact. One remained intact with 24 of the crew. The wreck was not found for more than 7 years: 23 June 1968, at 70°01′23″N 36°35′22"E.