These are used for harbor patrol and other close inshore work, and have often been carried by larger warships as a ship's boat.
[citation needed] The Union's 45-foot (14 m) long steam-powered Picket Boat Number One sank the Confederate ironclad Albemarle in 1864.
The boat was armed with a 12-pounder Dahlgren gun and a spar torpedo, of which the latter was employed in sinking Albemarle.
These boats were about 36 feet (11 m) long, had no main fixed armament, and cost about US$8,800 (about $156,452[4] in 2023 dollars) to build.
The typical main armament during most of this boat's service life was a Hotchkiss 3–pounder, adopted by the Royal Navy in 1886.