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.
USS Christabel (SP-162) was a civilian steam yacht that was built in Glasgow in 1893 for a Scottish industrialist. She had an American owner by 1910, served as a United States Navy patrol ship in the latter part of the First World War, and afterward was returned to US civilian service.
USS Halcyon II (SP-582) was a yacht acquired by the U.S. Navy during World War I. She was outfitted as an armed patrol craft and stationed in Boston harbor in Massachusetts. She spent much of the war patrolling the Massachusetts waterways for German submarines and, in 1919, was decommissioned after being damaged in a collision.
USS Wacondah (SP-238) was an advanced-design yacht acquired by the U.S. Navy during World War I. She was outfitted as an armed patrol craft assigned to guard the New York City harbor against German submarines and to provide escort protection to commercial ships. Post-war she was sold and continued her maritime career as the yacht Intercolonial.
USS Zoraya (SP-235) was an armed yacht that served in the United States Navy from 1917 to 1919.
USS Helena I (SP-24) was an armed yacht that served the United States Navy as a patrol vessel from 1917 to 1919.
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 Little Aie (SP-60) was an armed yacht that served in the United States Navy as a patrol vessel from 1917 to 1919.
USS Coco (SP-110) was an armed motorboat that served in the United States Navy as a Section patrol vessel from 1917 to 1919.
The third USS Mohican (SP-117), later USS SP-117, was an armed yacht that served in the United States Navy as a patrol vessel from 1917 to 1919.
USS Taniwha (SP-129) was an armed yacht 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 Wissoe II (SP-153) was an armed motorboat that served in the United States Navy as a patrol vessel from 1917 to 1919.
The second USS Sovereign (SP-170) was an armed yacht that served in the United States Navy as a patrol vessel from 1918 to 1919.
The third USS Seneca (SP-427), later USS SP-427, was a United States Navy minesweeper and patrol vessel in commission from 1917 to 1919.
The second USS Sylvia (SP-471), later USS SP-471, was a United States Navy patrol vessel in commission from 1917 to 1919.
USS Arcady (SP-577) was a United States Navy patrol vessel in commission from 1917 to 1919.
USS Vivace (SP-583) was a United States Navy patrol vessel in commission from 1917 to 1918.
The second USS Calumet (SP-723) was a United States Navy patrol vessel in commission from 1917 to 1919.
USS Marpessa (SP-787) was a 50 foot "express yacht" that became a United States Navy section patrol vessel in commission from 1917 to 1919 retaining the civilian name.
United States