USS Thornback (SS-418), a Tench-class submarine, was the only ship of the United States Navy to be named for the thornback, a slender member of the shark family with a long pointed snout and a sharp spine at the end of each dorsal fin, native to northern Atlantic waters ranging from the temperate to the Arctic. Her keel was laid down on 5 April 1944 by the Portsmouth Navy Yard. She was launched on 7 July 1944 sponsored by Mrs. Peter K. Fischler, and commissioned on 13 October 1944 with Commander Ernest P. Abrahamson in command. World War II On 10 November 1944 Thornback collided with USS CG-74327 (sank); one seaman was killed. Thornback stood out of New London, Connecticut, on 20 March 1945 bound, via the Panama Canal, for the Hawaiian Islands. She arrived at Pearl Harbor on 25 May and conducted training in Hawaiian waters prior to getting underway on 11 June for the western Pacific. As she stood down the Pearl Harbor channel, a formation of Landing Craft Infantry (LCIs), running down the wrong side of the channel, forced Thornback to crowd dangerously near the extreme edge of the channel. In the process, the submarine damaged her sound dome, necessitating repairs and a two-day delay in departing. She set sail for Saipan on 13 June, but she was rerouted to Guam. En route to the Mariana Islands, Thornback conducted an average of four training dives daily, in conjunction with battle problems, drills, and emergency surfacing exercises, before she arrived at Guam on 25 June. As lead ship of a wolf pack nicknamed "Abe's Abolishers", Thornback stood out to sea on 30 June, bound for the Japanese home islands. By this point in the war, American and British task forces steamed within easy gun range of Japanese coastal targets with near impunity. Japan's merchant marine and Navy had dwindled in size. Allied submarines and aircraft had taken an ever-increasing toll. In the air, Japan's once vaunted air forces had been struck from the skies. Sweeping ahead of Third Fleet Task Forces, the "Abolishers" made antipicket boat sweeps in the Tokyo-Yokohama area before proceeding to hunting grounds off the east coast of Honshū and south of Hokkaidō. Rough seas, strong winds, and generally poor visibility prevailed during Thornback’s patrol. She sighted a hospital ship on 5 July and let it pass. Six days later, a minor fire in the