Aircraft carrier
There is no single definition of an "aircraft carrier". and modern navies use several variants of the type. These variants are sometimes categorized as sub-types of aircraft carriers, and sometimes as distinct types of aviation-capable ships. Aircraft carriers may be classified according to the type of aircraft they carry and their operational assignments. Admiral Sir Mark Stanhope, former head of the Royal Navy, has said that "To put it simply, countries that aspire to strategic international influence have aircraft carriers".
Carriers have evolved since their inception in the early twentieth century from wooden vessels used to deploy balloons to nuclear-powered warships that carry dozens of aircraft, including fighter jets and helicopters. As of 16 February 2014, there are thirty-seven active aircraft carriers in the world within twelve navies. The United States Navy has ten large nuclear-powered carriers, known as supercarriers, carrying up to ninety aircraft, the largest carriers in the world. As well as the supercarrier fleet, the US Navy has nine amphibious assault ships used primarily for helicopters; these can also carry up to twenty-five fighter jets, and in some cases are as large as some other nations' fixed-wing carriers.
History of the aircraft carrier
Most early aircraft carriers were conversions of ships that were laid down (or had even served) as different ship types: cargo ships, cruisers, battlecruisers, or battleships. During the 1920s, several navies started ordering and building aircraft carriers that were specifically designed as such. This allowed the design to be specialized to their future role, and resulted in superior ships. During the Second World War, these ships would become the backbone of the carrier forces of the US, British, and Japanese navies, known as fleet carriers.
World War II saw the first large-scale use of aircraft carriers and induced further refinement of their launch and recovery cycle leading to several design variants. The USA built small escort carriers, such as USS Bogue, as a stop-gap measure to provide air support for convoys and amphibious invasions. Subsequent light aircraft carriers, such as USS Independence, represented a larger, more "militarized" version of the escort carrier concept. Although the light carriers usually carried the same size air groups as escort carriers, they had the advantage of higher speed as they had been converted from cruisers under construction.
HMS Hermes, temporarily converted as an experimental seaplane carrier in April–May 1913, was also one of the first seaplane carriers, and the first experimental seaplane carrier of the Royal Navy. She was originally laid down as a merchant ship, but was converted on the building stocks to be a seaplane carrier for a few trials in 1913, before being converted again to a cruiser, and back again to a seaplane carrier in 1914. She was sunk by a German submarine in October 1914. The first seaplane tender of the US Navy was the USS Mississippi, converted to that role in December 1913.
In September 1914, during World War I, in the Battle of Tsingtao, the Imperial Japanese Navy seaplane carrier Wakamiya conducted the world's first successful naval-launched air raids.It lowered four Maurice Farman seaplanes into the water using its crane. These seaplanes later took off to bombard German forces, and were retrieved back from the surface afterwards