Escort carrier
The escort carrier or escort aircraft carrier, also called a "jeep carrier" or "baby flattop" in the United States Navy or "Woolworth Carrier" by the Royal Navy, was a small and slower type of aircraft carrier used by the Royal Navy, the Royal Canadian Navy, the United States Navy, the Imperial Japanese Navy and Imperial Japanese Army Air Force in World War II. They were typically half the length and a third the displacement of larger fleet carriers, more-lightly armed and armored, and carried fewer planes. Escort carriers were most often built upon a commercial ship hull, so they were cheaper and could be built quickly. This was their principal advantage as they could be completed in greater numbers as a stop-gap when fleet carriers were scarce. However, the lack of protection made escort carriers particularly vulnerable, and several were sunk with great loss of life. The light carrier was a similar concept to the escort carrier in most respects, but was fast enough to operate alongside fleet carriers.
Escort carriers were too slow to keep up with the main forces consisting of fleet carriers, battleships, and cruisers. Instead, they were used to escort merchant ship convoys, defending them from enemy threats such as submarines and planes. In the invasions of mainland Europe and Pacific islands, escort carriers provided air support to ground forces during amphibious operations. Escort carriers also served as backup aircraft transports for fleet carriers, and ferried aircraft of all military services to points of delivery.
In the Battle of the Atlantic, escort carriers were used to protect convoys against U-boats. Initially escort carriers accompanied the merchant ships and helped to fend off attacks from aircraft and submarines. As numbers increased later in the war, escort carriers also formed part of hunter-killer groups that sought out submarines instead of being attached to a particular convoy.
In the Pacific theater, CVEs provided air support of ground troops in the Battle of Leyte Gulf. They lacked the speed and weapons to counter enemy fleets, relying on the protection of a Fast Carrier Task Force. However, at the Battle off Samar, one U.S. task force of escort carriers and destroyers managed to successfully defend itself against a much larger Japanese force of battleships and cruisers. The Japanese met a furious defense of carrier aircraft, screening destroyers, and destroyer escorts.
Of the 151 aircraft carriers built in the U.S. during World War II, 122 were escort carriers, though no examples survive. The was the most numerous class of aircraft carrier, with 50 launched. Second was the, with 45 launched.
Development
In the early 1920s, the Washington Naval Treaty imposed limits on the maximum size and total tonnage of aircraft carriers for the five main naval powers. Later treaties largely kept these provisions. As a result, construction between the World Wars had been insufficient to meet operational needs for aircraft carriers as World War II 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 provided additional aircraft carriers until new construction became available.Conversions of cruisers and passenger liners with speed similar to fleet carriers were identified by the U.S. as "light aircraft carriers" able to operate at battle fleet speeds. Slower conversions were classified as "escort carriers" and were considered naval auxiliaries suitable for pilot training and transport of aircraft to distant bases.
The Royal Navy had recognized a need for carriers to defend its trade routes in the 1930s. While designs had been prepared for "trade protection carriers" and five suitable liners identified for conversion, nothing further was done – mostly because there were insufficient aircraft for even the fleet carriers under construction at the time. However, by 1940 the need had become urgent and was converted from the captured German merchant ship MV Hannover and commissioned in July 1941. For defense from German aircraft, convoys were supplied first with fighter catapult ships and CAM ships that could carry a single fighter. In the interim, before escort carriers could be supplied, they also brought in merchant aircraft carriers that could operate four aircraft.
In 1940, U.S. Admiral William Halsey recommended construction of naval auxiliaries for pilot training. In early 1941 the British asked the U.S. to build on their behalf six carriers of an improved Audacity design, but the U.S. had already begun their own escort carrier. On 1 February 1941, the United States Chief of Naval Operations gave priority to construction of naval auxiliaries for aircraft transport. U.S. ships built to meet these needs were initially referred to as auxiliary aircraft escort vessels in February 1942 and then auxiliary aircraft carrier on 5 August 1942. The first U.S. example of the type was. 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. U.S. classification revision to escort aircraft carrier on 15 July 1943 reflected upgraded status from auxiliary to combatant. 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 was designed to incorporate the best features of American CVLs on a more stable hull with a less expensive propulsion system.
Among their crews, CVE was sarcastically said to stand for "Combustible, Vulnerable, and Expendable", and the CVEs were called "Kaiser coffins" in honor of Casablanca-class manufacturer Henry J. Kaiser. Magazine protection was minimal in comparison to fleet aircraft carriers. was sunk within minutes by a single torpedo, and exploded from undetermined causes with very heavy loss of life. Three escort carriers—, and —were destroyed by kamikazes, the largest ships to meet such a fate.
Allied escort carriers were typically around long, not much more than half the length of the almost fleet carriers of the same era, but were less than of the weight. A typical escort carrier displaced about, as compared to almost for a full-size fleet carrier. The aircraft hangar typically ran only of the way under the flight deck and housed a combination of 24–30 fighters and bombers organized into one single "composite squadron". By comparison, a late Essex-class fleet carrier of the period could carry 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. Although the first escort carriers had only one aircraft elevator, having two elevators, along with the single aircraft catapult, quickly became standard. The carriers employed the same system of arresting cables and tail hooks as on the big carriers, and procedures for launch and recovery were the same as well.
The crew size was less than of that of a large carrier, but this was still a bigger complement than most naval vessels. U.S. escort carriers were large enough to have 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 available on board.
In all, 130 Allied escort carriers were launched or converted during the war. Of these, six were British conversions of merchant ships:,,,, and. The remaining escort carriers were U.S.-built. Like the British, the first U.S. escort carriers were converted merchant vessels. The Bogue-class carriers were based on the hull of the Type C3 cargo ship. The last 69 escort carriers of the and Commencement Bay classes were purpose-designed and purpose-built carriers drawing on the experience gained with the previous classes.
Royal Navy
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 that were put into service by the British and Dutch as an emergency measure until dedicated 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 joined convoys, not as fighting ships but as transporters, ferrying aircraft from the U.S. to Britain; twice as many aircraft could be carried 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 provided a grog ration. The heavy duty washing machines of the laundry room were removed, since "all a British sailor needs to keep clean is a bucket and a bar of soap".
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.