Observation seaplane

As the range of dreadnought battleship guns exceeded the distance from which shipboard personnel could observe shell splashes, observation aircraft were employed to: • locate targets • observe fall of shot for trajectory correction of large caliber naval artillery, and • assess damage to enemy ships. Wartime experience following the 1916 Battle of Jutland indicated additional usefulness for: • directing submarines to positions for torpedo kill-shots on disabled enemy capital ships • search and rescue missions, and • air cover for infantry landing operations. As aircraft carriers replaced battleships during World War II, observation seaplanes became vulnerable to radar-directed fighter aircraft and were reassigned for: • reconnaissance and photo intelligence gathering, • liaison, and • radio communication support for local activities including amphibious operations. Their shipboard roles were replaced by helicopters following the second world war. ==Catapult and recovery procedures==

After the plane was fueled and the engine warmed up, or the engine oil pre-heated, the pilot and observer would climb into their aircraft and rev the engine at full throttle. If the instrument panel readings were satisfactory, the pilot would brace for takeoff and signal the catapult operator he was ready. The United States Navy catapult used a smokeless powder charge to accelerate the plane to per hour. (0 to 80 in one-half second) A capital ship preparing to recover its aircraft would steam into the wind and signal the aviator which way it would turn across the wind to provide a sheltered landing surface. When the plane was in position the ship would turn so the plane could land on the lee side as close as possible to the ship. The ship would tow a net along the water surface from a boom on the lee side, and the plane would taxi over the net so a hook on the underside of the float would engage the net allowing the plane to cut power and minimize relative movement of the plane with respect to the ship while the ship's crane hoisted the plane aboard. ==United States==

Two early aircraft assembled by Glenn Curtiss prior to formation of the Curtiss Aeroplane and Motor Company arrived aboard on 24 April 1914 under the command of Henry C. Mustin to conduct aerial reconnaissance during the United States occupation of Veracruz. This was the first operational use of naval aircraft and the first time U.S. aviators of any service were the target of ground fire. On 5 November 1915 Mustin pioneered United States Navy catapult operations piloting an AB-2 seaplane launched from the cruiser . Interest in aerial observation increased as combat experience during first world war naval engagements demonstrated the inability of shipboard observers to accurately report fall of shot from the engagement range of dreadnought battleships. Nine Vought VE-7s were delivered in 1924 to be launched from battleship catapults. Subsequent design improvements were the Vought FU and Vought O2U Corsair. A few Berliner-Joyce OJ float planes were built for the Omaha class light cruiser catapults. The Curtiss SOC Seagull became the dominant United States Navy catapult seaplane in 1935, until the number of Vought OS2U Kingfishers manufactured during the second world war exceeded the total production of all previous United States Navy observation seaplanes. In the absence of gunnery engagements with other warships, capital ships' observation seaplanes were used to spot naval gunfire support; but they proved so vulnerable to land-based fighters during the amphibious invasion of Sicily that their pilots flew conventional fighters spotting gunfire for the invasion of Normandy. A few Curtiss SC Seahawks remained operational into the late 1940s until helicopters became reliable enough to replace observation seaplanes. ==United Kingdom==

fuselage. The first seaplane used in a naval battle was a Short Type 184 launched from in the opening stages of the 1916 Battle of Jutland. The plane was forced down by a broken fuel line after locating a few cruisers, and the clumsy procedure of finding calm water to offload and launch took so long that Engadines other planes were unable to meaningfully participate. This experience encouraged development of the Fairey III to be operated from aircraft carriers. The Supermarine Seagull II was the first British aircraft to be catapult launched in 1925. This design was improved as the Supermarine Walrus serving aboard capital ships of the Royal Navy through the second world war. Royal Navy preference for the flying boat fuselage was unusual among the shipboard observation seaplanes of the major naval powers. ==Japan==

carried 24 seaplanes When the Washington Naval Treaty left Japan with fewer capital ships than the United States or the United Kingdom, the country focused on aviation as a means of balancing naval power. Although according to the Japanese Navy aircraft designation system, only the Mitsubishi F1M was officially designated as an "observation seaplane" (F prefix), there were numerous similar "reconnaissance seaplanes" (E), as well as "flying boats" (H), "seaplane fighter" (N), and "special purpose seaplanes" (M), which could serve a similar role. Japan produced observation and reconnaissance seaplanes in larger numbers and greater diversity than any other nation (with more than 4700 airframes). The first Japanese design was the Nakajima E2N in 1927. Increasing numbers of Nakajima E4N, Kawanishi E7K, and Nakajima E8N were manufactured before the Aichi E13A was produced in similar numbers to the American OS2U Kingfisher, with the Kawanishi E15K Shiun and Aichi E16A Zuiun being the ultimate development of the type. Notably, both heavy cruisers where purpose built "aircraft cruisers", each carrying six seaplanes for the Kidō Butai reconnaissance role, to allow the full complement of aircraft carrier planes to focus on their attack role. In the later years of the war, several ships where converted to carry more seaplanes to accomplish the same role, such as the cruiser Mogami (1943), and the oiler Hayasui (1944). In addition to launching from capital ships, these Japanese seaplanes operated from fast seaplane tenders providing aviation support similar to aircraft carriers during fleet activities and amphibious operations. F dessignation The planes receiving the "F" designation (proper observation seaplanes) were required to fly and climb fast with a level of defense including armament and in-combat maneuverability. This requirement was not only for the traditional spotter functions but also for: • Air cover for local operations away from a fleet, and • Repelling of enemy reconnaissance planes. In contrast, long operational range aircraft with less regard to armament and maneuverability received either the C, E, or R designations, respectively for carrier aircraft, seaplnes, and land-based aircraft, with also the Q designation for maritime pattrol and submarine-warfare. Ministry of Navy issued a design request based on the F requirement in 1935, and comparative evaluation was carried out among F1A (Aichi), F1M (Mitsubishi) and F1K (Kawanishi) in flight testing. After a modification, Mitsubishi F1M won the Navy production contract with excellent climb rate and maneuverability, and went into service in 1941 with a formal Navy type designation "Type Zero Observation Aircraft". For a plane with floats, F1M2 performance was beyond expectations at the time with 9 min 36 s to 5000 m climb rate, and especially its maneuverability in dog-fights where pilots rated it superior to the Zero Fighter-converted fighter seaplane A6M2-N, which often surprised the US fighter pilots in the early stages of the Pacific Theater of WWII. and this series was further developed into submarine launched dive bomber / torpedo attacker Aichi M6A Seiran with maximum speed of and over range, that was more than capable of observation/reconnaissance roles. ==Germany==

uses the original dual float configuration. German rearmament in the 1930s included Heinkel He 60, Heinkel He 114 and Arado Ar 196 float planes for launch from the catapults of the Kriegsmarines capital ships. A few later operated aboard merchant raiders. ==Comparison of ship-launched seaplanes==

The following is not an exhaustive list, but compares the observation and reconnaissance seaplanes produced in greatest numbers. ==See also==