Updated August 2 Documents show no cover-up in sinking of submarine USS Thresher, skipper says The loss of the Maine-built nuclear-powered submarine and all 129 people aboard during a test dive in 1963 was both a tragedy for the families and a blow to national pride during the Cold War. By DAVID SHARPAssociated Press Read Article The 278-foot-long nuclear powered attack submarine USS Thresher, a first in its class boat, is launched bow-first at the Portsmouth Navy Yard in Kittery on July 9, 1960. The USS Thresher sank on April 10, 1963, killing all 129 crew on board, during an Atlantic Oce...