<P> After the disaster at Pearl Harbor, Roosevelt turned to the most aggressive sailor available, Admiral Ernest J. King (1878 - 1956). Experienced in big guns, aviation and submarines, King had a broad knowledge and a total dedication to victory . He was perhaps the most dominating admiral in American naval history; he was hated but obeyed, for he made all the decisions from his command post in the Washington, and avoided telling anyone . The civilian Secretary of the Navy was a cipher whom King kept in the dark; that only changed when the Secretary died in 1944 and Roosevelt brought in his tough - minded aide James Forrestal . Despite the decision of the Joint Chiefs of Staff under Admiral William D. Leahy to concentrate first against Germany, King made the defeat of Japan his highest priority . For example, King insisted on fighting for Guadalcanal despite strong Army objections . His main strike force was built around carriers based at Pearl Harbor under the command of Chester Nimitz . Nimitz had one main battle fleet, with the same ships and sailors but two command systems that rotated every few months between Admiral Bull Halsey and Admiral Raymond A. Spruance . The Navy had a major advantage: it had broken the Japanese code . It deduced that Hawaii was the target in June 1942, and that Yamamoto's fleet would strike at Midway Island . King only had four carriers in operation; he sent them all to Midway where in a miraculous few minutes they sank the Japanese carriers . This gave the Americans the advantage in firepower that grew rapidly as new American warships came on line much faster than Japan could build them . King paid special attention to submarines to use against the overextended Japanese logistics system . They were built for long - range missions in tropical waters, and set out to sink the freighters, troop transports and oil tankers that held the Japanese domains together . The South West Pacific Area, based in Australia, was under the control of Army General Douglas MacArthur; King assigned him a fleet of his own under Admiral Thomas C. Kinkaid, without any big carriers . </P> <P> On 7 December 1941, Japan's carriers launched the Attack on Pearl Harbor, sinking or disabling the entire battleship fleet . The stupendous defeat forced Admiral King to develop a new strategy based on carriers . Although the sunken battleships were raised, and many new ones were built, battleships played a secondary role in the war, limited chiefly to bombardment of islands scheduled for amphibious landings . The "Big Gun" club that had dominated the Navy since the Civil War lost its clout . </P> <P> The U.S. was helpless in the next six months as the Japanese swept through the Western Pacific and into the Indian Ocean, rolling up the Philippines as well as the main British base at Singapore . After reeling from these defeats the Navy stabilized its lines in summer 1942 . </P> <P> At the start of the war, the United States and Japan were well matched in aircraft carriers, in terms of numbers and quality . Both sides had nine, but the Mitsubishi A6M Zero carrier fighter plane was superior in terms of range and maneuverability to its American counterpart, the F4F Wildcat . By reverse engineering a captured Zero, the American engineers identified its weaknesses, such as inadequate protection for the pilot and the fuel tanks, and built the Hellcat as a superior weapon system . In late 1943 the Grumman F6F Hellcats entered combat . Powered by the same 2,000 horsepower Pratt and Whitney 18 - cylinder radial engine as used by the F4U Corsair already in service with the Marine Corps and the UK's allied Fleet Air Arm, the F6Fs were faster (at 400 mph) than the Zeros, quicker to climb (at 3,000 feet per minute), more nimble at high altitudes, better at diving, had more armor, more firepower (6 machine guns fired 120 bullets per second) than the Zero's two machine guns and pair of 20 mm autocannon, carried more ammunition, and used a gunsight designed for deflection shooting at an angle . Although the Hellcat was heavier and had a shorter range than the Zero, on the whole it proved a far superior weapon . Japan's carrier and pilot losses at Midway crippled its offensive capability, but America's overwhelming offensive capability came from shipyards that increasingly out produced Japan's, from the refineries that produced high - octane gasoline, and from the training fields that produced much better trained pilots . In 1942 Japan commissioned 6 new carriers but lost 6; in 1943 it commissioned 3 and lost 1 . The turning point came in 1944 when it added 8 and lost 13 . At war's end Japan had 5 carriers tied up in port; all had been damaged, all lacked fuel and all lacked warplanes . Meanwhile, the US launched 13 small carriers in 1942 and one large one; and in 1943 added 15 large and 50 escort carriers, and more arrived in 1944 and 1945 . The new American carriers were much better designed, with far more antiaircraft guns, and powerful radar . </P>

Why did the us expand its naval forces in the 1890s and early 1900s