USS Tusk (SS-426), a , was the only ship of the United States Navy to be named for the tusk, an alternate name for the cusk, a large edible saltwater fish related to the cod. Her keel was laid down on 23 August 1943 at Philadelphia by the Cramp Shipbuilding Company. She was launched on 8 July 1945 sponsored by Mrs. Carolyn Park Mills, and commissioned on 11 April 1946.
Tusk and are erroneously listed with the Tench class in some sources, as their hull numbers are in the sequence assigned to that class.
Shakedown and GUPPY Conversion
Tusk completed her shakedown cruise in the southern Atlantic with a round of goodwill visits to Latin American ports. She called at Rio de Janeiro and Bahia in Brazil, Curaçao in the Netherlands West Indies, and at Colón in the Panama Canal Zone before returning to New London, Connecticut, in June. For the next year, she conducted operations along the East Coast between New London and Wilmington, North Carolina. During the first month of 1947, Tusk participated in a fleet tactical exercise in the Central Atlantic. A three-month overhaul at Philadelphia, followed by oceanographic work along the Atlantic shelf in conjunction with Columbia University and the Woods Hole Oceanographic Institution occupied her until October 1947 when she entered the Portsmouth Naval Shipyard for a Greater Underwater Propulsive Power Program (GUPPY) conversion.
Over the next seven months, Tusk received extensive modifications to improve her submerged performance characteristics. Four "greater capacity" batteries replaced her old larger ones. Her hull became more streamlined—the anchors were recessed into the hull and the propeller guards were removed—to improve her overall hydrodynamic design for underwater operations. Her sail was streamlined and enlarged to house the snorkel, a device added to allow her to operate on diesel power at periscope depth and to recharge her batteries while running submerged. All of these changes helped to convert Tusk from simply a submersible surface ship into a truer submarine. They increased her submerged range; and, though she lost about two knots in surface speed, her submerged speed increased from just under to about .
The newly converted submarine returned to active duty early in the summer of 1948. She conducted her shakedown training and made a simulated war patrol to the Panama Canal Zone in June and July. She returned to the United States in August and visited the United States Naval Academy at Annapolis, Maryland, where her presence allowed about 1000 fourth-classmen to see at firsthand the latest development in submarine design. That fall and winter, Tusk resumed normal operations, participating in exercises with other United States and NATO forces. She ranged from the Caribbean Sea in the south to above the Arctic Circle in the north. The beginning of 1949 brought a more restricted radius of operations. During the first six months of that year, she served with Submarine Development Group 2 based at Newport, Rhode Island. In July, Tusk rejoined the multinational forces of NATO for another round of exercises in the North Atlantic. During these exercises, she visited Derry, Northern Ireland, and Portsmouth, England.
Loss of Cochino
During the final phase of those exercises, Tusk was operating in a unit which also included the submarine . On 25 August, while steaming through a gale off the coast of Norway, Cochino suffered an explosion in one of her batteries. Tusk rushed to the aid of the stricken submarine, providing medical supplies for Cochinos injured by way of life rafts. One such raft capsized in heavy seas sending a Cochino officer and a civilian employee of the Bureau of Ships into the icy Arctic Sea. Both were recovered, but during the administration of artificial respiration on board Tusk, another wave broke over her deck washing away the civilian and 11 Tusk crewmen. Only four sailors were subsequently rescued. After those tragic events, Tusk and the limping Cochino headed for Hammerfest, Norway. Along the way, another explosion erupted in Cochinos aft battery. The second detonation sealed Cochinos fate. Water poured through her battered hull. Tusk came alongside in heavy seas and lashed herself to the sinking submarine. Under the worst possible conditions, Tusk took all of Cochinos crew off safely. Minutes later Cochino took her final plunge and Tusk headed for Hammerfest.