United States Navy torpedo retrievers

The first sinking of a ship by a self-propelled torpedo occurred in 1878, and by World War I, torpedoes played a pivotal role in naval warfare as German U-boats sought to close the North Atlantic to allied shipping. While the United States had experimented with early torpedoes, the U-boat threat in World War I focused undersea warfare efforts on anti-submarine technologies rather than torpedoes. At the close of World War I, U.S. defense spending was reduced, further curtailing the development of torpedo systems. Consequently, U.S. Navy experience with torpedoes was quite limited prior to World War II. At the start of the conflict there was no one in the Navy who had ever seen or heard a torpedo detonate either in test or war. No U.S. submarine sank a vessel using a torpedo until 1941. In this environment of economy, testing and trainining were limited. Only two types of small purpose-built torpedo retrievers, 40' and 42' boats, were built. There were few enough of these that it was common for unspecialized motorboats to recover exercise torpedoes.World War II brought about a large increase in U.S. Navy use of torpedoes. Prior to the war, about 60 torpedoes per month were manufactured. Over the next four years nearly 50,000 were produced. The most recent generations of torpedo retrievers are much more than that, as their designations suggest. They are now categorized as range support craft, and multi-purpose craft. They not only retrieve torpedoes, but new classes of weapons including missiles, and autonomous undersea vehicles. They launch drones and other targets. They tow various targets and lower sound transducers into the sea to simulate enemy vessels. They are capable of extended operation away from port, sailing independently, and have capacity to retrieve many exercise weapons without having to return to base. For most of their history, torpedo retrievers have been manned by Navy enlisted personnel. A recent development is the outsourcing of operation and maintenance of these vessels. While the Navy continues to own the boats, civilian contractors and crew will run many of them. The Pacific Missile Range Facility, have all moved toward placing civilian crews aboard their range support craft. Torpedo retrieval techniques Exercise torpedoes are intended to float on the surface when they reach the end of their runs. Various techniques have been used to achieve this. For example, the submarine-launched Mark 14 torpedo of World War II replaced its warhead with an exercise head filled with water. At the end of the torpedo's run, compressed air would expel the water, lightening the weapon sufficiently to float. Modern torpedoes have electric propulsion systems that leave no trail of bubbles for a retriever to follow. They also rely on homing and other technologies that can change a weapon's course once fired. Further complicating location is that torpedoes are more likely to be used against deep-diving submarines, rather than surface ships, so not only is their course less predictable, but also the depth at which they run. Once a torpedo has been located, the next step in retrieval is to attach a line to it. A variety of snares and slings that encircle the body of the weapon, and various nosepieces have been used to attach lines to the otherwise smooth object. Slings and nose cages have been attached to the weapons either by swimmers, by sailors working from a small boat, or by sailors operating from the torpedo retriever itself. Having located and captured a spent torpedo, it could now be recovered. The early 40' and 42' torpedo retrievers had no ability to bring a weapon on board. Their crews would snare a floating torpedo, tie a line to it, and tow it to a dock or ship where it could be craned out of the water. In the absence of purpose-built torpedo retrievers, a wide variety of small boats performed similarly. Disadvantages of these early vessels included their inability to operate in difficult sea conditions, to stay on station overnight, to navigate on their own, and to recover more than one torpedo per trip. These early retrievers had no radios. They would communicate by raising a "bravo" signal flag to indicate they were recovering a torpedo. Beginning in the 1950s, the Navy experimented with training a variety of marine mammals to recover sunken torpedoes. Orca, beluga whales, pilot whales, and bottle-nosed dolphins were all trained with some level of success. As robots became more capable and cheaper, this program was discontinued. Helicopters are also capable of recovering floating torpedoes using specialized nets, but they suffer from a number of disadvantages compared to torpedo recovery boats. They are in short supply, have limited flight times, are expensive, have limited lifting capacity, and can pick up just a single torpedo per trip. The United States Air Force has also operated drone and missile retriever boats to support its own training and development requirements and continues to do so to the present day. == U.S. Navy torpedo retrievers ==