Types of carrier
(note: some of the types listed here are not strictly defined as aircraft carriers by some sources)
A fleet carrier is intended to operate with the main fleet and usually provides an offensive capability. These are the largest carriers capable of fast speeds. By comparison, escort carriers were developed to provide defense for convoys of ships. They were smaller and slower with lower numbers of aircraft carried. Most were built from mercantile hulls or, in the case of merchant aircraft carriers, were bulk cargo ships with a flight deck added on top. Light aircraft carriers were fast enough to operate with the main fleet but of smaller size with reduced aircraft capacity. Soviet aircraft carriers now in use by Russia are actually called heavy aviation cruisers; these ships, while sized in the range of large fleet carriers, were designed to deploy alone or with escorts, and provide both strong defensive weaponry and heavy offensive missiles equivalent to a guided missile cruiser, in addition to supporting fighters and helicopters.
Aircraft carriers today are usually divided into the following four categories based on the way that aircraft take off and land:
- Catapult-assisted take-off barrier arrested-recovery (CATOBAR): these carriers generally carry the largest, heaviest, and most heavily armed aircraft, although smaller CATOBAR carriers may have other limitations (weight capacity of aircraft elevator, etc.). All CATOBAR carriers in service today are nuclear powered. Two nations currently operate carriers of this type: ten Nimitz class and one Gerald R. Ford class fleet carriers by the United States, and one medium-sized carrier by France, for a world total of twelve in service.
- Short take-off but arrested-recovery (STOBAR): these carriers are generally limited to carrying lighter fixed-wing aircraft with more limited payloads. STOBAR carrier air wings, such as the Sukhoi Su-33 and future Mikoyan MiG-29K wings of Admiral Kuznetsov are often geared primarily towards air superiority and fleet defense roles rather than strike/power projection tasks, which require heavier payloads (bombs and air-to-ground missiles). Today China, India, and Russia each operate one carrier of this type – a total of three in service currently.
- Short take-off vertical-landing (STOVL): limited to carrying STOVL aircraft. STOVL aircraft, such as the Harrier Jump Jet family and Yakovlev Yak-38 generally have limited payloads, lower performance, and high fuel consumption when compared with conventional fixed-wing aircraft; however, a new generation of STOVL aircraft, currently consisting of the F-35B, has much improved performance. The US has nine STOVL amphibious assault ships. The UK has a class of two 65,000 ton STOVL aircraft carriers, HMS Queen Elizabeth and HMS Prince of Wales, the largest warships ever built for the Royal Navy; with one in service and the other being fitted out. Italy operates two in the light fleet role, and Spain operates one amphibious assault ship as a STOVL aircraft carrier, giving a total of thirteen STOVL carriers in active service; (Thailand has one active STOVL carrier but it no longer has any operational STOVL aircraft in inventory so is used and counted as a helicopter carrier).
- Helicopter carrier: Helicopter carriers have a similar appearance to other aircraft carriers but operate only helicopters – those that mainly operate helicopters but can also operate fixed-wing aircraft are known as STOVL carriers (see above). There are currently fourteen helicopter carriers (that solely operate helicopters and not fixed-wing aircraft), operated by seven navies, in commission today. Japan has four of this type, France three, Australia two, Egypt two, and South Korea, Thailand, and Brazil have one each. In the past, some conventional carriers were converted and called commando carriers by the Royal Navy. Some helicopter carriers, but not all, are classified as amphibious assault ships, tasked with landing and supporting ground forces on enemy territory.
The Japanese carrier Shinano
was the biggest carrier in World War II, and the largest ship destroyed by a submarine.
The appellation "supercarrier" is not an official designation with any national navy, but a term used predominantly by the media and typically when reporting on new and upcoming aircraft carrier types. It is also used when comparing carriers of various sizes and capabilities, both current and past. It was first used by The New York Times in 1938, in an article about the Royal Navy's HMS Ark Royal, that had a length of 209 metres (686 ft), a displacement of 22,000 tonnes and was designed to carry 72 aircraft. Since then, aircraft carriers have consistently grown in size, both in length and displacement, as well as improved capabilities; in defense, sensors, electronic warfare, propulsion, range, launch and recovery systems, number and types of aircraft carried and number of sorties flown per day.
While the current classes in service, or planned, with the navies of China, India, Russia, and the UK, have displacements ranging from 65,000 to 85,000 tonnes, lengths ranging from 280 meters (920 ft) to 320 meters (1,050 ft) and varying capabilities, have been described as "supercarriers", the largest "supercarriers" currently in service are with the US Navy, with displacements exceeding 100,000 tonnes, lengths of over 337 meters (1,106 ft), and capabilities that match or exceed that of any other class.
Hull type identification symbols
Several systems of identification symbol for aircraft carriers and related types of ship have been used. These include the pennant numbers used by the British Royal Navy and some Commonwealth countries, the hull classification symbols used by the US, NATO and some other countries, and the Canadian hull classification symbols.