Section G.4: What happened to USS Thresher and USS Scorpion?
USS Thresher (SSN 593) was lost 10 April 1963 off the New England coast. All 112 naval personnel and 17 civilians aboard were killed. The vessel was on post-overhaul trials, operating from Portsmouth (NH) Naval Shipyard. The submarine was in communication with a surface vessel during her loss. It is believed that her reactor shut down during deep diving trials; she then attempted to blow her tanks to surface, and the expanding air from the tanks froze the air lines. She could not surface with the reactor shut down (reportedly it would take 45 minutes to restart such a reactor) and the air lines frozen. The cause of the reactor shutdown is not known. Thresher was crushed by water pressure as she sank. USS Mizar (AGOR 11) located the wreckage of the submarine in 1964; the site has been surveyed several times since then. USS Scorpion (SSN 589) was declared lost 6 June 1968. It was determined (presumably by examination of SOSUS tapes or other evidence) that she was lost on 22 May 1968, 400
