Anti-submarine warfare carrier
An anti-submarine warfare carrier (ASW carrier) is a type of small aircraft carrier whose primary role is to hunt and destroy submarines. This type of ship came into existence during the Cold War as a development of the escort carriers used in the ASW role in the North Atlantic during World War II.
After World War II, the main naval threat to most Western nations was confrontation with the Soviet Union. The Soviets ended the war with a small navy and took the route of asymmetric confrontation against Western surface ship superiority by investing heavily in submarines both for attack and later fielding submarine-launched missiles. Several nations who purchased British and US surplus light carriers were most easily able to accommodate slow-moving, less expensive, and easy-to-land anti-submarine aircraft from the 1960s forward, such as the S-2 Tracker, which flew from the decks of US, Canadian, Australian, Dutch, Argentine, and Brazilian carriers, or Alizé, which flew from French and Indian ships, allowing these ships to still remain useful especially in the framework of NATO even as newer fighter and strike aircraft were becoming too heavy for the equipment designed for WWII aircraft.
Improvement in long-range shore-based patrol and conventional ship-based ASW helicopter capability combined with the increasing difficulty maintaining surplus WWII carriers led to most of these ships being retired or docked by smaller nations from the 1970s to the mid-1980s. This trend in ASW force draw-down only accelerated with the massive reduction in the operational Soviet/Russian submarine fleet, which rarely went to sea in large numbers in the 1990s. Ships that could be called dedicated ASW carriers are now only found with the Japanese navy, which operates helicopters and no fixed-wing carrier-based aircraft of any kind. Even the United States Navy, the last nation to regularly operate a dedicated fixed-wing carrier-based ASW aircraft, the S-3 Viking, on its mixed-role super carriers had already removed most ASW equipment in the 1990s from this aircraft and has now removed this type from service as of January 2009 without replacement. Interestingly, the Argentine Navy, currently without much hope of a replacement CATOBAR carrier of its own, still trains several times a year landing S-2 Turbo Trackers aboard the Brazilian carrier São Paulo.
Much easier to operate from small decks than fixed-wing aircraft were ASW helicopters, which flew from the decks of nearly all allied conventional carriers to this day and most LPH or STOVL carriers operated by the Soviet, Spanish, Italian, Japanese, British, and Thai navies. Since the only navy currently building new ASW through-deck helicopter-only ships is Japan, who terms their vessels as helicopter destroyers instead of ASW carriers, it is disputable if an ASW helicopter-only vessel is best defined as an ASW carrier or given a new designation.
 List of ASW carriers
Aircraft carriers and helicopter carriers that had primary ASW duties from the mid-1960s onward.
- Argentine Navy
- ARA Independencia - one ship (ex-Colossus class) ASW (retired/scrapped) fixed-wing CATOBAR S-2 and helicopters
- ARA Veinticinco de Mayo - one ship (ex-Colossus class) ASW (retired/scrapped) fixed-wing CATOBAR S-2 and helicopters
- Brazilian Navy
- NAeL Minas Gerais - one ship (ex-Colossus class) ASW (retired/scrapped) fixed-wing CATOBAR and helicopters
- French Navy
- Arromanches - one ship (ex-Colossus class) ASW (retired/scrapped) fixed-wing CATOBAR and helicopters
- Italian Navy
- Giuseppe Garibaldi one ship, ASW helicopter carrier 1985-1988, STOVL fighters and ASW helicopters carrier 1988-.
- Japan Maritime Self-Defense Force
- Spanish Navy
- Dédalo - one ship (ex-Independence class) ASW helicopter carrier 1967-1976, STOVL carrier 1976-1989. Strike/ASW (retired/scrapped) STOVL and helicopters
- Principe de Asturias one ship STOVL fighters and helicopters
- Royal Navy
- HMS Bulwark Centaur class aircraft carrier In 1979 recommissioned from reserve as a helicopter ASW carrier. (retired/scrapped)
- HMS Hermes Centaur class aircraft carrier Converted to helicopter ASW in 1976. (sold to India, renamed INS Viraat)
- Invincible class - three ships Strike/ASW/Amphibious Assault STOVL and helicopters. These ships were originally designed as through deck cruisers for the ASW role, but ended up also equipped with Harrier STOVL fighters. After the Falklands War they were used as conventional, albeit light, fleet aircraft carriers in the power projection role.
- Royal Australian Navy
- HMAS Melbourne - one ship (Majestic class) Strike/ASW (retired/scrapped) fixed-wing CATOBAR and helicopters
- Royal Canadian Navy
- HMCS Bonaventure - one ship (ex-Majestic class) ASW (retired/scrapped) fixed-wing CATOBAR and helicopters
- Royal Netherlands Navy
- HNLMS Karel Doorman - one ship (ex-Colossus class) ASW (retired/sold to Argentina as Veinticinco de Mayo, scrapped) fixed-wing CATOBAR and helicopters
- Soviet/Russian Navy
- Moskva class ASW helicopter support ship, large rear deck landing pad and hangar for 18 helicopters (retired/scrapped) Helicopters only
- Kiev Class cruiser/carrier guided missile cruiser/limited air defense/ASW (retired/sold) STOVL and helicopters
- United States Navy
- Essex class - ASW carriers with fixed-wing and helicopter anti-submarine aircraft and AEW aircraft, although occasionally carried an A-4 Skyhawk detachment (4 aircraft) for daytime combat air patrol (retired/scrapped) fixed-Wing CATOBAR and helicopters
- Wasp class, Tarawa class, and the LPH Amphibious assault ships were given secondary roles of sea control meaning they would deploy with a modified air complement consisting of helicopters for ASW coverage and a larger STOVL fighter group for air defense and even limited strike missions, but lack AEW.
 See also
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