Escort carrier

The escort aircraft carrier or escort carrier (popularly known as the "jeep carrier"), was a small aircraft carrier utilized by the Royal Navy, the Imperial Japanese Navy and the United States Navy in World War II. In the Atlantic the escort carriers were employed to deal with the U-boat crisis of the Battle of the Atlantic, while in the Pacific they provided air support to ground forces during amphibious operations, served as backup aircraft transports for fleet carriers, and transported aircraft of all military services to points of delivery.

Of the 151 aircraft carriers built in the United States during WWII, 122 were escort carriers. The "Casablanca" class holds the distinction of being the most numerous single class of aircraft carrier ever built, with 50 having been launched, the "Bogue" class escort carrier coming in a close second, with 45 launched.

World War II

Aircraft carrier construction between the world wars had been insufficient to meet operational needs for aircraft carriers as the second world war expanded from Europe. Too few fleet carriers were available to simultaneously transport aircraft to distant bases, support amphibious invasions, offer carrier landing training for replacement pilots, conduct anti-submarine patrols, and provide defensive air cover for deployed battleships and cruisers. The foregoing mission requirements limited use of fleet carriers' unique offensive strike capability demonstrated at the Battle of Taranto and the Attack on Pearl Harbor. Conversion of existing ships (and hulls under construction for other purposes) provided additional aircraft carriers until new construction became available. Conversions of cruisers, passenger liners, and fleet oilers with speed similar to fleet carriers were identified by the United States as light aircraft carriers (hull classification symbol CVL) able to operate at battle fleet speeds. Slower conversions were considered naval auxiliaries suitable for pilot training and transport of aircraft to distant bases.

The Royal Navy had recognized a need for trade defense carriers in the 1930's. [Hague 2000 p.83] No construction was undertaken until HMS "Audacity" was converted from the captured German merchant ship MV "Hannover" and commissioned in July 1941. In 1940, Admiral William Halsey recommended construction of naval auxiliaries for pilot training. [Friedman 1983 p.162] On 1 February 1941, the United States Chief of Naval Operations gave priority to construction of naval auxiliaries for aircraft transport. [Friedman 1983 p.165] United States ships built to meet these needs were initially referred to as auxiliary aircraft escort vessels (AVG) in February 1942 and then auxiliary aircraft carrier (ACV) on 5 August 1942.Evans, Robert L. "Cinderella Carriers" "United States Naval Institute Proceedings" August 1976 pp.53-60] The first United States example of the type was USS Long Island (AVG-1). Operation Torch and North Atlantic anti-submarine warfare proved these ships capable aircraft carriers for ship formations moving at the speed of trade or amphibious invasion convoys. United States classification revision to escort aircraft carrier (CVE) on 15 July 1943 reflected upgraded status from auxiliary to combatant. [Friedman 1983 pp.159-160] They were informally known as "Jeep carriers" or "baby flattops." It was quickly found that the escort carriers had better performance than light carriers, which tended to pitch badly in moderate to high seas. The "Commencement Bay" class was designed to incorporate the best features of American CVLs on a more stable hull with a less expensive propulsion system. [Friedman 1983 p.159]

CVE was sarcastically said to stand for "Combustible, Vulnerable, and Expendable". Magazine protection was minimal in comparison to fleet aircraft carriers. [Friedman 1983 p.176] HMS "Avenger" was sunk within minutes by a single torpedo, and HMS "Dasher" exploded from undetermined causes with very heavy loss of life. Three escort carriers — USS "St. Lo", USS "Ommaney Bay" and USS "Bismarck Sea" — were destroyed by kamikazes, the largest ships to meet such a fate.

Allied escort carriers were typically around 500 ft (150 m) long, not much more than half the length of the almost 900 ft (300 m) fleet carriers of the same era, but actually less than one-third of the size: a typical escort carrier displaced about 8,000 tons, as compared to almost 30,000 tons for a full-size fleet carrier. The aircraft hangar typically ran only a third of the way under the flight deck and housed a combination of 24 to 30 fighters and bombers organized into one single 'composite squadron'. (A late "Essex" class fleet carrier could carry a total of 103 aircraft organized into separate fighter, bomber and torpedo-bomber squadrons)

The island on these ships was small and cramped, and located well forward of the funnels (unlike on a normal-sized carrier where the funnels were integrated into the island). Although the first escort carriers had only one aircraft elevator, two elevators, one fore and one aft, quickly became standard, so did the one aircraft catapult. The carriers employed the same system of arresting cables and tailhooks as on the big carriers, and procedures for launch and recovery were the same as well.

The crew size was less than a third of that of a large carrier, but this was still a bigger complement than most naval vessels. It was large enough to justify the existence of facilities such as a permanent canteen or snack bar, called a gedunk bar, in addition to the mess. The bar was open for longer hours than the mess and sold several flavors of ice cream, along with cigarettes and other consumables. There were also several vending machines, which made a "gedunk" sound when operated.

Originally developed at the behest of the United Kingdom to operate as part of a North Atlantic convoy escort rather than as part of a naval strike force, many of the escort carriers produced were assigned to the Royal Navy for the duration of the war under the Lend-lease act. They supplemented and then replaced the converted merchant aircraft carriers which were put into service by the British and Dutch as an emergency measure until the escort carriers became available. As convoy escorts, they were used by the Royal Navy to provide air scouting, to ward off enemy long-range scouting aircraft and, increasingly, to spot and hunt submarines. Often additional escort carriers also joined convoys, not as fighting ships but as transporters, ferrying aircraft from the US to Britain. In this case the aircraft cargo could be doubled by storing aircraft on the flight deck as well as in the hangar.

The ships sent to the Royal Navy were slightly modified, partly to suit the traditions of that service. Among other things the ice cream making machines were removed, since they were considered unnecessary luxuries on ships which served grog and other alcoholic beverages. The heavy duty washing machines of the laundry room were also removed since "all a British sailor needs to keep clean is a bucket and a bar of soap" (quoted from Warrilow).

Other modifications were due to the need for a completely enclosed hangar when operating in the North Atlantic and in support of the Arctic convoys.

Meanwhile the US discovered their own use for the escort carriers. In the North Atlantic, they supplemented the escorting destroyers by providing air support for their anti-submarine warfare. One of these escort carriers, the USS "Guadalcanal", was instrumental in the capture of the German submarine (U-boat) U-505 off North Africa in 1944. The Guadalcanal and her task force were commanded by Captain (later Admiral) Daniel V. Gallery. (In 1955 the U-505 was moved to Chicago, restored, and made a permanent exhibit at the Chicago Museum of Science and Industry.)

In the Pacific theatre, escort carriers often escorted the landing ships and troop carriers during the island-hopping campaign. In this role they provided air cover for the troopships and flew the first wave of attacks on beach fortifications in amphibious landing operations. On occasion they even escorted the large carriers, serving as emergency airstrips and providing fighter cover for their larger sisters while these were busy readying or refueling their own planes. They also transported aircraft and spare parts from the US to remote island airstrips.

Perhaps the finest moment for these escort carriers was the Battle of Leyte Gulf's Battle off Samar, where three escort carrier groups, along with their escort destroyers, fended off the battleships of the Japanese Combined Fleet, allowing General Douglas MacArthur's Army to complete the liberation of Leyte.

In all, 130 Allied escort carriers were launched or converted during the war. Of these, six were British conversions of merchant ships: HMS "Audacity", HMS "Nairana", HMS "Campania", HMS "Activity", HMS "Pretoria Castle" and HMS "Vindex". The remaining escort carriers were US-built. Like the British, the first US escort carriers were converted merchant vessels (or in the "Sangamon" class, converted military oilers). The "Bogue" class carriers were based on the hull of the Type C3 cargo ship. The last 69 escort carriers of the "Casablanca" and "Commencement Bay" classes were purpose-designed and purpose-built carriers drawing on the experience gained with the previous classes.

For complete lists see:
* list of escort aircraft carriers of the United States Navy
* list of escort aircraft carriers of the Royal Navy
* List of ships of the Japanese Navy

USN escort carrier Division Commanders in World War II

* Rear Admiral Gerald R. Henderson
* Vice Admiral Ralph A. Ofstie
* Rear Admiral William Sample
* Vice Admiral Clifton A. F. Sprague
* Vice Admiral Thomas L. Sprague
* Admiral Felix B. Stump

Escort carrier tactics when escorting convoys

There are three basic tactics for operating an escort carrier in defence of a convoy:

* Within the convoy, which gives it the protection of the convoy's escort but limits the space to turn into the wind to operate aircraft.
* Near the convoy, which gives the carrier freedom of manoeuvre, but puts it outside the screen provided by the convoy's escort, making it necessary for the carrier to have its own separate escort. The carrier is also likely to be spotted by enemy forces approaching the convoy, making it vulnerable to attack.
* Some distance away from the convoy. This increases the time required for aircraft to reach the convoy but reduces the risk of being spotted by forces attacking the convoy.

HMS "Audacity" was sunk while operating in the second position which was later banned by the Admiralty as too risky.

The ships

Many escort carriers were Lend-Leased to the United Kingdom, this list specifies the breakdown in service to each navy.

"Long Island" class - 2 ships, 1 in USN service (USS "Long Island" (CVE-1)) and 1 in British service (HMS "Archer").
"Charger" class - 4 ships, 1 mainly in USN service (USS "Charger"), 3 in British service as "Avenger" class.
"Sangamon" class - 4 ships, all in USN service.
"Bogue" class - 45 ships, 11 in USN service, 34 in British service as "Attacker" class (first batch) and "Ameer" class (second batch).
"Casablanca" class - 50 ships, all in USN service.
"Commencement Bay" class - 19 ships, all in USN service, including two which were accepted but not commissioned and laid up for many years after the war. 4 more units were canceled and scrapped on the building slips. The "Commencement Bay" class ships were seen as the finest escort carriers ever built, and several units continued in service after the war as training carriers, aircraft ferries and other auxiliary uses.

In addition, 6 escort carriers were produced by the British during the war {all converted from other vessels}.

The table below compares escort carriers to similar ships performing the same missions. The first four were built as early fleet aircraft carriers. Merchant aircraft carriers (MAC) carried trade cargo in addition to operating aircraft. Aircraft transports carried larger numbers of planes by eliminating accommodation for operating personnel and storage of fuel and ammunition.

Relative carrier sizes in World War II

Post World War II

The years following World War II brought many revolutionary new technologies to the navy, most notably the helicopter and the jet fighter, and with this a complete rethinking of its strategies and ships' tasks. Although several of the latest "Commencement Bay"-class CVE were deployed as floating airfields during the Korean war, the main reasons for the development of the escort carrier had disappeared or could be dealt with better by newer weapons. The emergence of the helicopter meant that helicopter-deck equipped frigates could now take over the CVE's role in a convoy while also performing their own traditional role as submarine hunters. Ship-mounted guided missile launchers took over much of the aircraft protection role, and in-flight refueling abolished the need for floating stopover points for transport or patrol aircraft. As a result, after the "Commencement Bay" class, no new escort carriers were designed, and with every downsizing of the navy, the CVEs were the first to be mothballed.

Several escort carriers were pressed back into service during the first years of the Vietnam war because of their ability to carry large numbers of aircraft. Redesignated AKV (air transport auxiliary), they were manned by a civilian crew and used to ferry whole aircraft and spare parts from the United States to Army, Air Force and Marine bases in South Vietnam. However, CVEs were only useful in this role for a limited period. Once all major aircraft were equipped with refueling probes, instead of shipping a plane overseas to its pilot, it became much easier to fly the aircraft directly to its base.

The last chapter in the saga of the escort carriers consisted out of two conversions: As an experiment, the USS "Thetis Bay" was converted from an aircraft carrier into a pure helicopter carrier (CVHA-1) and used by the Marine Corps to carry assault helicopters for the first wave of amphibious warfare operations. Later, the "Thetis Bay" became a full amphibious assault ship (LHP-6). Although in service only from 1955 (the year of her conversion) to 1964, the experience gained in her training exercises greatly influenced the design of today's amphibious assault ships.

In the second conversion, in 1961 the USS "Gilbert Islands" had all her aircraft handling equipment removed and four tall radio antennas installed on her long, flat deck. In lieu of aircraft, the hangar deck now had no less than 24 military radio transmitter trucks bolted to its floor. Rechristened USS "Annapolis" (AGMR-1), the ship was used as a communication relay ship and served dutifully through the Vietnam War as a floating radio station, relaying transmissions between the forces on the ground and the command centers back home. Like the "Thetis Bay", the experience gained before she was stricken in 1976 helped develop today's purpose-built amphibious command ships of the "Blue Ridge" class.

Unlike almost all other major classes of ships and patrol boats from World War II, most of which can be found in a museum or port, no escort carrier or light carrier has survived: all were destroyed during the war or broken up in the following decades. The last escort carrier, USS "Gilbert Islands", was broken up for scrap starting in 1976. The last light carrier (the escort carrier's faster sister type) was the USS "Cabot", which was broken up in 2002 after a decade-long attempt to preserve the vessel.

ee also

* CAM ship
*Merchant aircraft carrier

Notes

References

* Galuppini, Gino. "Le guide des porte-avions". Paris: Fernand Nathan, 1981
* Poolman, Kenneth. "Escort carrier 1941-1945: An account of British Escort Carriers in Trade Protection". London: Ian Allan, 1972
* Warrilow, Betty. "Nabob, the first Canadian-manned aircraft carrier". Owen Sound, Ont. : Escort Carriers Association, 1989.
* Gallery, Daniel V. "20 Million Tons Under The Sea". Ballantine, 1965.
* Al Adcock. "Escort Carriers in action". Squadron/Signal publications. Printing date unknown.
*

* cite book
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*

*

* cite book
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*cite book
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