During the Washington Conference of 1920, the Americans took a hard look at their Navy. They had a Navy second only to the British, and like the Royal Navy, they had to protect interests in two oceans. Yet voluntarily they gave up building several ships and scrapped others. Unlike the Japanese and German Navies, the Americans would hold themselves to the Treaties and build ships that would be outclassed just a few years later by their Axis counterparts.
Just twenty-five years later, the United States Navy would field thousands of ships and aircraft over Tokyo Bay. The transformation would occur within four years; most of the ships in Tokyo Bay were not even on the drawing table in 1940. The creation of a purpose-built amphibious fleet was an industrial miracle. Most of the specialized designs were British inventions built in American yards.
Two men were most responsible for engineering the mass construction. Henry J. Kaiser, who invented new ways to build cargo ships, started building ships faster than the Axis could sink them, ensuring that the supplies could get through. Andrew J. Higgins built a new kind of landing craft that could drop its front ramp, allowing easy disembarkation. Many different types of these boats would be built for the US Navy. Mastering the ability to supply operations from the sea was a technique the Axis never matched, and it provided a powerful weapon to the Allied cause.
With the losses at Pearl Harbor, the United States Navy under Admiral Chester W. Nimitz was forced to undertake a whole tactical doctrine. Since the invention of gunpowder, ships had been essentially floating gun platforms. With the US carriers the only capital ships left in early 1942, they were the only units able to bring the fight to the enemy.
Nimitz and his staff, William “Bull” Halsey, Raymond A. Spruance, and Admiral Frank Fletcher, created new ways of operating the carrier task forces. While the same ships comprised the Third Fleet under Halsey and the Fifth Fleet under Spruance, the command staffs could plan the next operation while the current one was still underway. This provided a tactical advantage that the Japanese, with huge losses among their flag officers, could never make up.
The aircraft on the carrier decks were getting better also. The US Navy started the war with three obsolescent types: the F4F Wildcat fighter, the SBD Dauntless dive-bomber, and the TBF Devastator torpedo bomber. They were quickly replaced with aircraft that were more powerful and better armed than their Japanese equivalents. The F6F Hellcat, F4U Corsair, the TBF Avenger, and the SB2C Helldiver were multipurpose aircraft that added napalm and rockets to their inventory by 1944. The fighters could outfly the Mitsubishi A6M2 type 00 aircraft, and anything except a Nakajima Ki-100 Hayate. As the war ended, even better fighters were en route to the war zone.
When the war started, problems with the American torpedo limited the effectiveness of submarines and PT boats. By 1943, the redesigned torpedo allowed submarines to sneak into Japanese Home waters and sink anything they found. In 1945, there was little Japanese shipping available for an island nation that could not sustain its population with homegrown agriculture.
At the end of the war, much of the US Navy was mothballed. The Americans had surpassed the British as the world’s major sea power, and it was the only Navy to maintain a battleship in operation until the 1990's. All the world’s navies have now phased them out. It is ironic that the only navy to operate true fixed-wing aircraft carriers in the 21st century kept the dinosaur battleship in service for so long.