The Vought OS2U Kingfisher is an American catapult-launched observation floatplane. It was a compact mid-wing monoplane, with a large central float and small stabilizing floats. Performance was modest because of its low-powered engine. The OS2U could also operate on fixed, wheeled, taildragger landing gear.
The OS2U was the main shipboard observation seaplane used by the United States Navy during World War II, and 1,519 of the aircraft were built. It served on battleships and cruisers of the U.S. Navy, with the United States Marine Corps in Marine Scouting Squadron Three (VMS-3), with the United States Coast Guard at coastal air stations; at sea with the Fleet Air Arm of the Royal Navy; with the Soviet Navy; and with the Royal Australian Air Force.
The Naval Aircraft Factory OS2N was the designation of the OS2U-3 aircraft built by the Naval Aircraft Factory in Philadelphia, Pennsylvania. The OS2U first flew on 1 March 1938.
HMS Ark Royal was the first ship designed and built as a seaplane carrier. She was purchased by the Royal Navy in 1914 shortly after her keel had been laid and the ship was only in frames; this allowed the ship's design to be modified almost totally to accommodate seaplanes. During the First World War, Ark Royal participated in the Gallipoli Campaign in early 1915, with her aircraft conducting aerial reconnaissance and observation missions. Her aircraft later supported British troops on the Macedonian Front in 1916, before she returned to the Dardanelles to act as a depot ship for all the seaplanes operating in the area. In January 1918, several of her aircraft unsuccessfully attacked the German battlecruiser SMS Goeben when she sortied from the Dardanelles to attack Allied ships in the area. The ship left the area later in the year to support seaplanes conducting anti-submarine patrols over the southern Aegean Sea.
After the end of the war, Ark Royal mostly served as an aircraft transport and depot ship for those aircraft in support of White Russian and British operations against the Bolsheviks in the Caspian and Black Sea regions during the Allied intervention in the Russian Civil War. She also supported Royal Air Force (RAF) aircraft in British Somaliland in the campaign against Diiriye Guure's Darawiish and Mohammed Abdullah Hassan in 1920. Later that year, the ship was placed in reserve. Ark Royal was recommissioned to ferry an RAF squadron to the Dardanelles during the Chanak Crisis in 1922. She was reduced to reserve again upon her return to the United Kingdom the following year.
The ship was recommissioned in 1930 to serve as a training ship, for seaplane pilots and to evaluate aircraft catapult operations and techniques. She was renamed HMS Pegasus in 1934, freeing the name for the aircraft carrier ordered that year, and continued to serve as a training ship until the beginning of the Second World War in September 1939.
Assigned to the Home Fleet at the beginning of the war, she took on tasks as an aircraft transport, in addition to her training duties, until she was modified to serve as the prototype fighter catapult ship in late 1940. This type of ship was intended to defend convoys against attacks by German long-range maritime patrol bombers by launching fighters via their catapult to provide air cover for the convoy. Pegasus served in this role until mid-1941 when she reverted to her previous duties as a training ship. This lasted until early 1944 when she became a barracks ship. The ship was sold in late 1946 and her conversion into a merchant ship began the following year. However, the owner ran out of money during the process and Anita I, as she had been renamed, was seized by her creditors in 1949 and sold for scrap. She was not broken up until late 1950.