Soviet submarine Komsomolets

The Soviet submarine Komsomolets was a prototype of a new deep-diving class of Soviet submarines with a titanium hull. The Soviet name was Project 685 "Plavnik", with hull number K-278; the class was given the NATO reporting name "Mike".

On April 7, 1989, after thirty-nine days at sea, fire broke out in the stern. The fire spread to other compartments. The submarine's ballasting supply of compressed air was released from its tanks and the submarine surfaced. Once the sub was surfaced the hull split under internal pressure. The ship sank to the bottom of the Barents Sea in 1700 meters of water. Survivors were rescued by another Soviet vessel.

Radiation leakage from the reactor of the Komsomolets remains a concern of Norwegian scientists to this day. The Soviet and Russian governments initially denied that radiation leakage would pose a problem. Recently, the Russian Central Design Bureau for Marine Engineering (RUBIN) has developed submarine explorers to investigate the wreckage.