A fleet carrier is an aircraft carrier designed to operate with the main fleet of a nation's navy. The term was developed during World War II, to distinguish it from the escort carrier and other less capable types. [1] In addition to many medium-sized carriers, supercarriers, as well as some light carriers, are also classed as fleet carriers. [2]
Aircraft carriers were designed in the years between World War I and World War II. Flight decks were installed on several different types of ships to explore the possibilities of operating naval aircraft without the performance limitations of flotation devices required for seaplanes and flying boats. The most successful of these early aircraft carriers were built from battlecruisers. Battlecruisers typically had a speed of about 30 knots (56 km/h), which was several knots faster than the speed of contemporary battleships. Additional speed was not necessary for maintaining station with the battle fleet, but enabled the carrier to catch up with the battle fleet after temporarily leaving formation to turn into the wind for launch or recovery of aircraft. The speed of the carrier during launch effectively decreased the takeoff distance for embarked aircraft, so faster carriers could operate heavier aircraft with greater range and superior combat capability. As such naval aircraft became operational, no nation could risk fielding less capable aircraft; so the speed of later purpose-designed aircraft carriers was set by the speed of the converted battle cruisers. The Washington Naval Treaty of 1922 limited the displacement of purpose-designed aircraft carriers to 23,000 tons. [3]
The idea of a modern fleet carrier was developed in 1931 by Admirals J.J. Clark and Harry E. Yarnell of the United States Navy. Fleet carriers, instead of operating as scouts for the fleet, would operate in unison with the fleet, to ward off air attacks and to strike opposing forces from the air. Cruisers and destroyers would protect fleet carriers. The fleet carriers would then displace battleships as the preeminent assets of the surface fleet. [4] A fleet carrier would carry more than 50 aircraft, and be fast enough to keep up with other major elements of the fleet, such as cruisers and battleships. [5]
As combat experience demonstrated the importance of aircraft carriers, numerous ships were rapidly converted to operate aircraft during World War II; and it became important to differentiate ships with the speed and size allowed by the Washington Naval Treaty from ships that were slower and/or carried fewer aircraft. Ships of similar speed carrying fewer aircraft were identified as light aircraft carriers (CVL) and ships of lower speed became known as escort aircraft carriers (CVE). Fleet aircraft carrier became the term to distinguish front-line aircraft carriers from the generic description of any warship carrying aircraft. [6]
In the post-war era, the United States Navy sought to give aircraft carriers a strategic bombing capability in addition to their tactical role. The largest bombs carried by carrier aircraft during the second world war had been about 2,000 pounds (910 kg) but experience had indicated some hardened targets like submarine pens were impervious to bombs of less than 12,000 pounds (5,400 kg). The fleet carriers of World War II were incapable of operating meaningful numbers of aircraft large enough to carry such heavy bombs over anticipated distances with performance characteristics to avoid defending aircraft. The term fleet carrier then evolved to differentiate the supercarriers designed for strategic bombing roles from the older fleet carriers delegated limited tactical roles like anti-submarine (CVS) or amphibious warfare (LPH). [7]
The following is not an exhaustive list, but does provide context by comparing some examples, from three types, of fleet carriers active during WWII.
| Name | Type | Nation | Displacement | Speed | Aircraft | Reference |
|---|---|---|---|---|---|---|
| Akagi | battlecruiser conversion | Japan | 36,500 tons | 31 knots | 72 | [8] |
| Lexington | battlecruiser conversion | US | 36,000 tons | 34 knots | 88 | [9] |
| Courageous | battlecruiser conversion | UK | 22,500 tons | 30 knots | 42 | [10] |
| Yorktown | Washington Naval Treaty | US | 19,800 tons | 32 knots | 79 | [11] |
| Ark Royal | Washington Naval Treaty | UK | 22,000 tons | 31 knots | 54 | [12] |
| Hiryū | Washington Naval Treaty | Japan | 17,300 tons | 34 knots | 64 | [13] |
| Illustrious | post-treaty production | UK | 23,000 tons | 30 knots | 33 | [14] |
| Shōkaku | post-treaty production | Japan | 25,675 tons | 34 knots | 72 | [15] |
| Essex | post-treaty production | US | 27,100 tons | 33 knots | 90 | [16] |
The earliest carrier aircraft were designed as fighters, scouts and gunfire observers. Torpedo bombers were developed to slow enemy ships so friendly battleships might catch and sink them. Dive bombing tactics were developed as aircraft strength improved through the 1930s, but limited aircraft capacity encouraged production of dual-purpose fighter-bombers or scout-bombers rather than dedicated dive bombers. [17] Japanese and American fleet carriers usually carried fighter squadrons, torpedo bomber squadrons, and dive bomber squadrons through World War II; [18] but British fleet carriers were less likely to include a dive bomber squadron. [19] The fleet carriers' longer range bombers were often used for the scouting role. [20]
By the time of the Korean War, the typical United States Navy fleet carrier embarked two squadrons of jet fighters, two squadrons of piston fighter-bombers, and a squadron of attack planes. Smaller numbers of specialized aircraft were also carried, including night fighters, night-attack bombers, and planes uniquely modified for aerial reconnaissance, airborne early warning and control (AEW), electronic countermeasures (ECM), and carrier onboard delivery (COD). When the supercarriers became operational, they carried a heavy attack squadron, two light attack squadrons, and two fighter squadrons with similar numbers of specialized aircraft, except the night fighters and bombers. As improved aircraft sensors became available, one or more full squadrons of fighters and bombers became capable of night operations. [21]
Early United States 21st-century fleet carriers typically embarked 45 McDonnell Douglas F/A-18 Hornet aircraft for traditional fighter, attack and ECM roles with twelve Sikorsky SH-60 Seahawk helicopters, four Northrop Grumman E-2 Hawkeye AEW aircraft and two Grumman C-2 Greyhound COD aircraft. [22]
The escort carrier or escort aircraft carrier, also called a "jeep carrier" or "baby flattop" in the United States Navy (USN) 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.
Hiryū was an aircraft carrier built for the Imperial Japanese Navy (IJN) during the 1930s. Generally regarded as the only ship of her class, she was built to a modified Sōryū design. Her aircraft supported the Japanese invasion of French Indochina in mid-1940. She took part in the attack on Pearl Harbor and the Battle of Wake Island. During the first few months of the Pacific War, the ship supported the conquest of the Dutch East Indies in January 1942. The following month, her aircraft bombed Darwin, Australia; and continued to assist in the Dutch East Indies campaign. In April, Hiryū's aircraft helped sink two British heavy cruisers and several merchant ships during the Indian Ocean Raid.
Sōryū was an aircraft carrier built for the Imperial Japanese Navy (IJN) during the mid-1930s. A sister ship, Hiryū, was intended to follow Sōryū, but Hiryū's design was heavily modified and she is often considered to be a separate class. Sōryū's aircraft were employed in operations during the Second Sino-Japanese War in the late 1930s and supported the Japanese invasion of French Indochina in mid-1940. During the first months of the Pacific War, she took part in the attack on Pearl Harbor, the Battle of Wake Island, and supported the conquest of the Dutch East Indies. In February 1942, her aircraft bombed Darwin, Australia, and she continued on to assist in the Dutch East Indies campaign. In April, Sōryū's aircraft helped sink two British heavy cruisers and several merchant ships during the Indian Ocean raid.
Zuikaku was the second and last Shōkaku-class aircraft carrier built for the Imperial Japanese Navy (IJN) shortly before the beginning of the Pacific War. Zuikaku was one of the most capable Japanese aircraft carriers of the entire war.
Shōhō was a light aircraft carrier of the Imperial Japanese Navy. Originally built as the submarine support ship Tsurugizaki in the late 1930s, she was converted before the Pacific War into an aircraft carrier and renamed. Completed in early 1942, the ship supported the invasion forces in Operation MO, the invasion of Port Moresby, New Guinea, and was sunk by American carrier aircraft on her first combat operation during the Battle of the Coral Sea on 7 May. Shōhō was the first Japanese aircraft carrier to be sunk during World War II.
HMS Illustrious was the lead ship of her class of aircraft carriers built for the Royal Navy before World War II. Her first assignment after completion and working up was with the Mediterranean Fleet, in which her aircraft's most notable achievement was sinking one Italian battleship and badly damaging two others during the Battle of Taranto in late 1940. Two months later the carrier was crippled by German dive bombers and was repaired in the United States. After sustaining damage on the voyage home in late 1941 by a collision with her sister ship Formidable, Illustrious was sent to the Indian Ocean in early 1942 to support the invasion of Vichy French Madagascar. After returning home in early 1943, the ship was given a lengthy refit and briefly assigned to the Home Fleet. She was transferred to Force H for the Battle of Salerno in mid-1943 and then rejoined the Eastern Fleet in the Indian Ocean at the beginning of 1944. Her aircraft attacked several targets in the Japanese-occupied Dutch East Indies over the following year before Illustrious was transferred to the newly formed British Pacific Fleet (BPF). The carrier participated in the early stages of the Battle of Okinawa until mechanical defects arising from accumulated battle damage became so severe she was ordered home early for repairs in May 1945.
HMS Indomitable was a modified Illustrious-class aircraft carrier built for the Royal Navy during World War II. Originally planned to be the fourth of the class, she was redesigned to enable her to operate more aircraft, 48 instead of 36. A second hangar was added above the original, raising the flight deck by 14 feet (4.3 m), although the hangar-side armour had to be reduced to compensate. The lower hangar was made shorter than the upper hangar due to the need for extra workshops and accommodation to support the added aircraft.
HMS Formidable was an Illustrious-class aircraft carrier ordered for the Royal Navy before the Second World War. After being completed in late 1940, she was briefly assigned to the Home Fleet before being transferred to the Mediterranean Fleet as a replacement for her crippled sister ship Illustrious. Formidable's aircraft played a key role in the Battle of Cape Matapan in early 1941, and they subsequently provided cover for Allied ships and attacked Axis forces until their carrier was badly damaged by German dive bombers in May.
The Illustrious class was a class of aircraft carrier of the Royal Navy that included some of the most important British warships in the Second World War. They were laid down in the late 1930s as part of the rearmament of British forces in response to the emerging threats of Nazi Germany, Fascist Italy and Imperial Japan.
HMS Indefatigable was one of two Implacable-class aircraft carriers built for the Royal Navy (RN) during World War II. Completed in 1944, her aircraft made several attacks that year against the German battleship Tirpitz, inflicting only light damage; they also raided targets in Norway. The ship was transferred to the British Pacific Fleet (BPF) at the end of the year and attacked Japanese-controlled oil refineries in Sumatra in January 1945 before joining the American forces in March as they prepared to invade the island of Okinawa in Operation Iceberg. Indefatigable and the BPF joined the Americans in attacking the Japanese Home Islands in July and August. Following the end of hostilities she visited ports in Australia, New Zealand and South Africa.
HMS Courageous was the lead ship of her class of three battlecruisers built for the Royal Navy in the First World War. Designed to support the Baltic Project championed by First Sea Lord John Fisher, the ship was very lightly armoured and armed with only a few heavy guns. Courageous was completed in late 1916 and spent the war patrolling the North Sea. She participated in the Second Battle of Heligoland Bight in November 1917 and was present when the German High Seas Fleet surrendered a year later.
The Fairey Fulmar is a British carrier-borne reconnaissance aircraft/fighter aircraft which was developed and manufactured by aircraft company Fairey Aviation. It was named after the northern fulmar, a seabird native to the British Isles. The Fulmar served with the Royal Navy's Fleet Air Arm (FAA) during the Second World War.
HMS Furious was a modified Courageous-class battlecruiser built for the Royal Navy (RN) during the First World War. Designed to support the Baltic Project championed by the First Sea Lord, Lord Fisher, the ship was very lightly armoured and designed with a main battery of only two 18-inch guns. Furious was modified as an aircraft carrier while under construction. Her forward turret was removed and a flight deck was added in its place, such that aircraft had to manoeuvre around the superstructure to land. Later in the war, the ship had her rear turret removed and a second flight deck installed aft of the superstructure, but this was less than satisfactory due to air turbulence. Furious was briefly laid up after the war before she was reconstructed with a full-length flight deck in the early 1920s.
Ryūjō was a light aircraft carrier built for the Imperial Japanese Navy (IJN) during the early 1930s. Small and lightly built in an attempt to exploit a loophole in the Washington Naval Treaty of 1922, she proved to be top-heavy and only marginally stable and was back in the shipyard for modifications to address those issues within a year of completion. With her stability improved, Ryūjō returned to service and was employed in operations during the Second Sino-Japanese War. During World War II, she provided air support for operations in the Philippines, Malaya, and the Dutch East Indies, where her aircraft participated in the Second Battle of the Java Sea. During the Indian Ocean raid in April 1942, the carrier attacked British merchant shipping with her guns and aircraft. Ryūjō next participated in the Battle of Dutch Harbor, the opening battle of the Aleutian Islands campaign, in June 1942. She was sunk by American carrier aircraft in the Battle of the Eastern Solomons on 24 August 1942.
Zuihō was the name ship of her class of two light aircraft carriers built for the Imperial Japanese Navy. Originally laid down as the submarine tender Takasaki, she was renamed and converted while under construction into an aircraft carrier. The ship was completed during the first year of World War II and played a minor role in the Battle of Midway in mid-1942. She participated in the Guadalcanal Campaign during the rest of 1942. Significantly damaged during the Battle of the Santa Cruz Islands in that campaign, after repairs Zuihō covered the evacuation of Japanese forces from Guadalcanal in early 1943.
Ryūhō was a light aircraft carrier of the Imperial Japanese Navy. She was converted from the submarine tender Taigei, which had been used in the Second Sino-Japanese War. One of the least successful of the light aircraft carrier conversions due to her small size, slow speed and weak construction, during World War II, Ryūhō was used primarily as an aircraft transport and for training purposes, although she was also involved in a number of combat missions, including the Battle of the Philippine Sea.
The Zuihō class (瑞鳳型), also known as the Shōhō class (祥鳳型), consisted of two aircraft carriers built for the Imperial Japanese Navy (IJN) before World War II, the Zuihō and Shōhō. Both ships were originally built as submarine tenders, but were subsequently converted into carriers. Completed in early 1942, Shōhō supported the invasion forces in Operation MO, the invasion of Port Moresby, New Guinea, and was sunk by American carrier aircraft on her first combat operation during the Battle of the Coral Sea on 7 May. Shōhō was the first Japanese aircraft carrier to be sunk during World War II. Zuihō played a secondary role in the Battle of Midway in mid-1942 and did not engage any American aircraft or ships during the battle. The ship participated in the Guadalcanal campaign during the rest of 1942. She was lightly damaged during the Battle of the Santa Cruz Islands during this campaign and covered the evacuation of Japanese forces from the island in early 1943 after repairs.
Aircraft carrier air operations include a launch and recovery cycle of embarked aircraft. Launch and recovery cycles are scheduled to support efficient use of naval aircraft for searching, defensive patrols, and offensive airstrikes. The relative importance of these three missions varies with time and location. Through the first quarter-century of aircraft carrier operations, launch and recovery cycles attempted to optimize mission performance for ships with a straight flight deck above an aircraft storage hangar deck. Carrier air operations evolved rapidly from experimental ships of the early 1920s through the combat experience of World War II.
Operation Goodwood was a series of British carrier air raids conducted against the German battleship Tirpitz at her anchorage in Kaafjord in occupied Norway during late August 1944. It was the last of several attacks made by the Home Fleet during 1944 which sought to damage or sink Tirpitz and thereby eliminate the threat it posed to Allied shipping. Previous raids on Kaafjord conducted by Fleet Air Arm aircraft had involved only one air attack; in Operation Goodwood several attacks were made in a single week. The Royal Navy hoped that these raids would wear down the formidable German defences.