The Vought OS2U Kingfisher was designed as a catapult-launched, ship-based observation aircraft intended for use on U.S. Navy cruisers and battleships. Its primary missions involved locating enemy forces and spotting for naval gunfire. The aircraft was an all-metal, low-wing monoplane featuring a central main float and wingtip stabilizing floats. A notable technical achievement was the use of extensive spot-welding in its construction, a process developed jointly by Vought and the Naval Aircraft Factory (NAF) to reduce weight and drag.
Production began with the Vought-Sikorsky Division of United Aircraft in Stratford, Connecticut. The prototype first flew on either 1 March 1938 or 20 July 1938, depending on the source, and the type entered service in August 1940. As Vought's capacity became constrained, production was transferred to the NAF at the Philadelphia Naval Shipyard in September 1942. The NAF-built version, designated the OS2N-1, was essentially a NAF-produced OS2U-3. Total production reached 1,519 aircraft, with 1,218 built by Vought and 300 by NAF through November 1942.
Powered by a 450 hp Pratt & Whitney R-985-AN-2 Wasp Junior 9-cylinder radial engine, the Kingfisher reached a maximum speed of approximately 164 mph and had a service ceiling of 13,000 feet. The two-seat tandem layout included a pilot and an observer/gunner. Armament consisted of one fixed forward-firing 0.30 in Browning M1919 machine gun and one flexible 0.30 in machine gun for the observer. For anti-submarine operations, it could carry two 325-lb depth charges.
During World War II, the Kingfisher became legendary for air-sea rescue missions. Notable examples include the November 1942 rescue of WWI ace Eddie Rickenbacker and the April 30, 1944, mission at Truk Lagoon, where Lt(jg) John A. Burns rescued nine airmen. Additionally, Lt(jg) Rollin M. Batten Jr. earned the Navy Cross for a rescue on July 4, 1944, while operating an aircraft from the USS Indiana. Beyond the U.S. Navy, the aircraft was used by the U.S. Coast Guard for coastal patrols and by foreign navies, including the Royal Navy (100 aircraft), the Royal Australian Air Force (18 aircraft), and nations such as Chile, Mexico, and Uruguay. Some remained in service in Cuba and Uruguay until 1959.