United States Navy submarines, surface ships, and aircraft launch torpedoes, missiles, and autonomous undersea vehicles as part of training exercises. Typically, these training munitions have no warhead and are recovered from the sea and reused. Similarly, new naval weapons under development are launched at sea in performance trials. These experimental units also need to be recovered, in their case to obtain evaluation data. At various points in history, newly manufactured torpedoes were fired as a quality control measure and these, too, had to be recovered before issuing them to the fleet. The U.S. Navy has used a variety of boats to accomplish the retrieval of these test and training munitions. As their missions evolved over the last century they have been variously known as torpedo retr