An armed yacht was a yacht that was armed with weapons and was typically in the service of a navy. The word "yacht" was originally applied to small, fast and agile naval vessels suited to piracy and to employment by navies and coast guards against smugglers and pirates. Vessels of this type were adapted to racing by wealthy owners. The origin of civilian yachts as naval vessels, with their speed and maneuverability, made them useful for adaptation to their original function as patrol vessels. In the United States Navy armed yachts were typically private yachts expropriated for government use in times of war. Armed yachts served as patrol vessels during the Spanish–American War and the World Wars. In the latter conflicts, armed yachts were used as patrol vessels, convoy escorts, and in anti-submarine duties. In the United States, yachts were purchased from their owners with the owners given an option to repurchase their yacht at the close of hostilities.
The first USS Mustang (SP-36) was an armed yacht that served in the United States Navy as a patrol vessel from 1917 to 1919.
USS Riette (SP-107) was an armed motorboat that served in the United States Navy as a patrol vessel from 1917 to 1919.
USS Hoqua (SP-142) was an armed yacht that served in the United States Navy as a patrol vessel from 1917 to 1919.
USS Hopestill (SP-191) was a United States Navy patrol vessel in commission from 1917 to 1919.
USS Nirvana (SP-706), later USS SP-706, was a United States Navy patrol vessel in commission in 1917 and from 1918 to 1919.
The first USS Sabalo (SP-225) was a United States Navy patrol vessel in commission from 1917 to 1919. Following World War I, Sabalo was sold to private interests before returning to service as a patrol vessel in World War II, this time with the Royal Canadian Navy, renamed Cougar. Returning to private ownership following the war, the vessel sank in a hurricane in 1950.
The first USS Josephine (SP-913), later USS SP-913, was a United States Navy patrol vessel in commission from 1917 to 1918.
USS Manito II (SP-262) was a United States Navy patrol vessel in commission from 1917 to ca. 1919.
USS Kemah (SP-415) was a United States Navy patrol vessel in commission from 1918 to 1919.
USS Fli-Hawk (SP-550) was a United States Navy patrol vessel in commission from 1917 to 1919.
USS Tamarack (SP-561) was a United States Navy patrol vessel in commission from 1917 to 1919.
USS Raeo (SP-588) was a United States Navy patrol vessel in commission from 1917 to 1919. Prior to her U.S. Navy service, she operated as the motor passenger vessel Raeo from 1908 to 1917. After the conclusion of her U.S. Navy career, she served as the fishery patrol vessel USFS Kittiwake in the United States Bureau of Fisheries fleet from 1919 to 1940 and as US FWS Kittiwake in the Fish and Wildlife Service fleet from 1940 to 1942 and from 1944 to at least 1945, and perhaps as late as 1948. During World War II, she again served in the U.S. Navy, this time as the yard patrol boat USS YP-199. She was the civilian fishing vessel Raeo from 1948 to 1957, then operated in various roles as Harbor Queen from 1957 to 1997. She became Entiat Princess in 1998 and as of 2009 was still in service.
USS Joy (SP-643) was a United States Navy patrol vessel in commission from 1917 to 1918.
USS Owaissa (SP-659) was a United States Navy patrol vessel in commission from 1917 to 1919.
The first USS Tuna (SP-664) was a United States Navy patrol vessel in commission from 1917 to 1919.
USS Jimetta (SP-878) was a United States Navy patrol vessel in commission from 1917 to 1918.
USS Linta (SP-721) was a United States Navy patrol vessel in commission from 1917 to 1919.
The second USS Calumet (SP-723) was a United States Navy patrol vessel in commission from 1917 to 1919.
USS San Toy II (SP-996) was a United States Navy ship's tender and ferry in commission from 1917 to 1919.
United States