K-77 was a "Project 651" (also known by its NATO reporting name of Juliett-class) cruise missile submarine of the Soviet Navy. Her keel was laid down in the Krasnoye Sormovo shipyard in Gorky on 31 January 1963. K-77 was also used as the set for the motion picture K-19: The Widowmaker, starring Harrison Ford and Liam Neeson.
To fire the missiles, the ship had to surface and the missile tube was elevated to 15 degrees. The Echo II class carried eight "Shaddock") anti-ship cruise missiles mounted in pairs above the pressure hull.