The world's major navies developed four major roles for naval aircraft: reconnaissance, spotting for naval gunnery, attacking enemy fleet and shore installations, and defending the fleet from enemy aircraft. Navies first relied on seaplanes and land-based aircraft, but during World War I Britain began conversion of several ships into aircraft carriers. This undertaking came to include the battle cruisers Furious, Courageous, and Glorious, all of which served in World War II. The U.S. Navy commissioned its first aircraft carrier, the Langley, in 1922; in the same year Japan commissioned its first carrier, the Hosho.
Following World War I, the world's navies deployed catapult-launched seaplanes on their battleships and cruisers for reconnaissance and spotting. Many navies considered building aircraft carriers, but only Great Britain, Japan, and the United States built them in significant numbers. During the 1920s and 1930s, aviators in all three of these navies solved the many technical problems of carrier operations despite low budgets, some opposition, and the Washington and London treaties that limited the size, number, and armament of the carriers. Large new aircraft carriers joined the three navies' fleets in the late 1930s and early 1940s.
Each nation developed a force suited to its particular needs. The United States and Japan planned for operations across the vast and relatively empty stretches of the Pacific Ocean, where land air bases would be few. Both nations developed long-range seaplanes, such as the U.S. PBY Catalina, to extend their search range, although only the Japanese navy developed land-based bombers to support its carrier aircraft. Japan also sought to maximize the number of planes on its aircraft carriers. Limited by the size of the carriers' internal hangars, Japan's larger carriers generally carried between 70 and 80 planes. In U.S. carriers planes were parked on the decks, and hangars were used only for repair and maintenance. This enabled the United States to bring as many as 100 planes into battle. The U.S. Navy also took better advantage of folded-wing airplanes to fit large complements on its carriers. Keeping planes on deck also substantially increased the pace of flight operations on the American carriers, allowing planes to be launched at a much higher rate than that from the Japanese or British ships.
Britain planned for war in Europe, where its fleet was likely to confront land-based air power. For that reason, the British favored heavily armored aircraft carriers with armored flight decks capable of withstanding 500-lb bombs. Although this scale of protection reduced the British aircraft complement to half that of comparably sized American aircraft carriers, it paid off repeatedly during the war, when British aircraft carriers survived damage that would likely have sunk a U.S. or Japanese carrier. On 10 January 1941, while protecting a convoy bound from Alexandria to Malta, the Illustrious survived hits by 500 lb and 1,000 lb bombs and then survived further damage while under repair at Malta. Later in the war, several British carriers withstood hits from Japanese kamikaze aircraft with minimal damage.
Unlike the case in Japan or the United States, the Royal Air Force, rather than the navy, had authority over naval aviation. This divided leadership slowed innovation, and the Royal Navy entered the war with obsolete aircraft. Typical of this was its Fairey Swordfish biplane torpedo-bomber.
Japan developed its aviators into an elite strike force, selecting only 100 new aviators each year from its rigorous training program. In 1941, they flew the best naval aircraft in the world: the Mitsubishi A6M2 Reisen ("Zero") fighter—so named because it entered service in 1940, the Japanese year 5700, and was henceforth known as the type 0 (Reisen or Zero)—the Aichi D3A "Val" dive-bomber, and the B5N "Kate" torpedo-bomber. These aircraft sacrificed protection for speed and maneuverability, and they considerably outperformed and outranged U.S. naval aircraft. Japanese fleets sent their search planes out to almost 600 miles, compared with 350 miles for the U.S. Navy, and their strike aircraft had a combat radius of 300 miles, compared with 200 miles for most American aircraft.
The Zero established a deadly combat reputation, and Americans flying Grumman F4F Wildcats could only best it with careful tactics and teamwork. The U.S. Douglas SBD Dauntless proved an excellent dive-bomber and served through much of the war, but the obsolete TBD Devastator torpedo-bomber was slow and vulnerable. The U.S. Navy replaced it as soon as it could with the more modern TBF Avenger following the great carrier battles of 1942.
During the first two years of war, aircraft did little to fulfill the promises of prewar aviation advocates. German aircraft rarely hit British warships during the 1940 Norwegian Campaign, and the German battle cruisers Gneisenau and Scharnhorst sank Britain's aircraft carrier Glorious with gunfire. In November 1940, British carrier aircraft surprised Italian battleships docked at Taranto and torpedoed three of them, but this proved little to critics, who argued that battleships at sea would evade bombs and torpedoes and devastate attacking aircraft with their heavy defensive armament.
Critics were also unimpressed by the battering by land-based aircraft that British carriers sustained while escorting convoys through the Mediterranean. However, carrier aircraft proved critical in bringing the German battleship Bismarck to battle. On 16 May 1941, torpedoes dropped by the Swordfish, which had been launched from the Ark Royal, jammed the Bismarck's rudder. Yet it required the heavy guns of British battleships to actually sink the ship. Similarly, Japan's brilliantly conceived and executed attack on Pearl Harbor proved only that bases and stationary ships were vulnerable to surprise air attack. Three days later, though, Japanese navy G4M land-based bombers located and sank the newest British battleship, the Prince of Wales, and the battle cruiser Repulse in an hour-long battle off the coast of Malaya. The British warships shot down only 3 of 129 attacking aircraft. Aircraft would often dominate future sea battles.
Japanese and U.S. aircraft carriers engaged each other in battles in 1942. The first of these, the Battle of the Coral Sea, ended with roughly equal losses for both sides. At Midway, though, Japan lost four carriers and sank only one U.S. carrier, the Yorktown. There followed a series of grueling battles around Guadalcanal in which both navies suffered heavily. Aircraft carriers, loaded with fuel and ordnance, proved particularly vulnerable to even minor damage, and few survived the first year of war in the Pacific. The United States lost five of its seven carriers in these battles, and the sixth suffered heavy damage. Japan suffered similar losses to its carrier fleet; more than 400 of the 765 airmen who attacked Pearl Harbor had died in battle by the end of 1942, in part the consequence of a poor Japanese pilot replacement/ training system.
In a desperate effort to replace lost aircraft carriers, the United States and Japan converted light cruisers into small aircraft carriers, such as the U.S. 33-aircraft Independence, which joined the fleet in June 1943. Japan also added partial flight decks to two battleships, allowing them to launch but not recover planes, and it converted a Yamato-class battleship to an aircraft carrier, the 64,800-ton Shinano. Yet U.S. industry easily won the naval building race. Japan completed three carriers in 1943 and four in 1944–1945; the United States completed 17 of its large Essex-class carriers during the war and more than 60 smaller carriers. By mid-1944, the United States was launching a large aircraft carrier every month.
U.S. carrier operations became increasingly sophisticated after the 1942 battles. Improving radar, which by early 1944 could detect even low-flying aircraft, and new control and communications systems allowed American fighters to intercept attacking aircraft with great success. New ships, increasing antiaircraft armament, and the proximity fuse considerably improved fleet defense. Radar-equipped TBF Avengers proved adept at locating targets at sea and in the air, allowing the U.S. Navy to intercept attacking aircraft at night. Whereas the Japanese navy continued to rely on its prewar aircraft designs, the United States developed several new airplanes, which began joining the fleet in 1943. These included the excellent F6F Hellcat and F4U Corsair, which completely outclassed Japan's Zero in combat.
U.S. aircraft also joined the British Royal Navy—first Wildcats and later Corsairs, Hellcats, and Avengers. By 1943, the United States was supplying most of the Royal Navy's aircraft. U.S. industry also churned out dozens of small escort carriers for both its own navy and the British navy. Carrying two dozen aircraft, these "baby flattops" provided continuous air cover for convoys crossing the Atlantic. Other escort carriers formed the core of antisubmarine hunter-killer groups that prowled the ocean in search of German U-boats and reinforced convoys under attack. Combined with land-based air power, the escort carriers proved the answer to the threat from Germany's U-boats and, in mid-1943, turned the tide of the Battle of the Atlantic. They also provided vital air support for numerous amphibious invasions.
A series of U.S. carrier raids and air offensives further wore down Japanese air strength in the Pacific during 1943. By November, when the United States invaded Tarawa and began its drive across the Central Pacific, 11 U.S. carriers faced only 6 Japanese carriers. U.S. Navy carriers, supported by an enormous fleet train and logistical system, raided throughout the Pacific. They isolated Japanese-held islands before invasion, protected amphibious landings, and provided close air support for the invading soldiers and Marines. American training and combat performance continued to improve, and an excellent submarine and seaplane rescue service saved the lives of many American pilots shot down during these missions.
The Japanese carrier fleet, rebuilt from the 1942 battles and supported by land-based planes, confronted a far larger U.S. fleet in June 1944 in the Battle of the Philippine Sea. The result was the "great Marianas turkey shoot," as the better-trained and better-equipped Americans shot down scores of poorly trained Japanese pilots who failed to press home their attacks and often missed their targets. Japan lost 475 planes and almost as many pilots; the United States lost only 100 planes and 16 pilots. Japanese naval air power never recovered from this defeat.
In the Battle of Leyte Gulf in October 1944, Japan used 1 heavy aircraft carrier and 3 light carriers (with a total of only 116 planes on board) as a diversion to draw away the U.S. battle fleet so Japanese battleships and cruisers could attack the landing beaches. Instead of the superbly trained pilots who attacked Pearl Harbor, Japan relied on the kamikazes, whose suicidal attacks sank dozens of U.S. ships. In the Battle for Okinawa, the kamikazes inflicted more casualties on the U.S. Navy than it had sustained in all of its other wars combined. But the Japanese were unable to stem the U.S. Navy advance across the Pacific. Throughout the Pacific, from the Mariana Islands to the Philippines, Iwo Jima, and Okinawa, U.S. naval aircraft smashed Japanese defenses, destroyed Japanese aircraft, supported invasions, sank Japanese ships, and raided Japanese positions.
By 1945, four British aircraft carriers operated in the Pacific, and these joined more than a dozen American carriers in launching a series of devastating air attacks on Japanese positions in July and August. All told, 1,000 U.S. and 250 British carrier aircraft destroyed more than 3,000 Japanese aircraft in the air and on the ground, adding to the damage B-29 bombers had already inflicted on Japan's home islands. New aircraft carriers continued to join the U.S. fleet, although the first of large 47,000 ton Midway-class battle carriers were not commissioned until September 1945, after the end of the war. Of Japan's carriers, only the old, experimental Hosho survived the war. Japan's fortunes in the Pacific war had risen and then sunk with its aircraft carriers. Stephen K. Stein
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Stephen K. Stein