The Washington Naval Treaty: The Birth of the Modern Aircraft Carrier
While the Langley was primarily a test and training vessel, her initial trials led the Navy leadership to build larger aircraft carriers that could actually serve with the battle fleet. The problem was finding the money to build these new ships. The early 1920's were hardly the time to request funds for a new and unproved naval technology, when the fleet was desperately trying to hold onto the modern battleships constructed during the First World War. The solution came after the five great naval powers (the United States, Great Britain, Japan, France, and Italy) signed the world's first arms-control treaty at the Washington Naval Conference of 1922. Though the treaty set quotas and limits on all sorts of warship classes, including aircraft carriers, a bit of fine print provided all the signatories with the opportunity to get "something for nothing."
At the end of the war, several countries were constructing heavy battleships and battle cruisers,[7] which were still unfinished in the early 1920's. Meanwhile, the 1922 Washington Naval Treaty set limits on the maximum allowable displacement and gun size of individual ships, as well as a total quota of tonnage available to each signatory nation (the famous 5:5:3 ratio).[8] Even after scrapping older dreadnought-era battleships, the nations within the agreement were left with no room for building new battleships and battle cruisers (which were classed together because of gun size). However, the treaty allowed the signatories to convert a percentage of their allowable carrier tonnage from the hulls of the uncompleted capital ships. What made this especially attractive was that the new carriers could be armed with the same 8-in/203mm gun armament as a heavy cruiser. Thus, even if the aircraft carriers themselves proved to be unsuccessful, those heavy cruiser guns would still make the ships useful.
The British had already converted their tonnage quota with the Furious, Courageous, Glorious, and Eagle, while the Japanese converted their new carriers from the uncompleted battle cruiser Akagi and the battleship Kaga. The American vessels, however, were something special. The U.S. Navy wanted its two new carriers to be the biggest, fastest, and most capable in the world. The starting points were a pair of partially completed battle cruiser hulls. Already christened the Lexington and Saratoga, they were converted into the ships that the fledgling naval air arm had always dreamed of. When commissioned in 1927, the Lexington (CV-2) and Saratoga (CV-3) were not only the largest (36,000-tons displacement), fastest (thirty-five knots), most powerful warships in the world, (most important) they could operate up to ninety aircraft, twice the capacity of the Japanese or British carriers.[9] The Lexington and Saratoga also featured a number of new design features (such as the now-familiar "island" structures, which contained the bridge, flight control stations, and uptakes for the engineering exhausts), which greatly improved their efficiency and usefulness. The treaty-mandated gun turrets were placed in four mounts fore and aft of the island structure.
With the commissioning of the Lexington and Saratoga (and parallel rapid strides in naval aircraft design), the U.S. Navy took the world lead in naval aviation development. Virtually all of the American leaders who commanded carriers and air units during the Second World War served their early tours of duty aboard the two giant carriers. In addition, the series of fleet problems (war games) involving the Lexington and Saratoga led to the tactics America would take into the coming Pacific war with Japan.
The Taranto Raid and the Sinking of the Battleship Bismarck
Always leaders in the development of naval aviation technology and tactics, the British had planned for and assimilated the aircraft carrier into their fleet long before the opening of the Second World War. This was not merely institutional integration, for there were also plans for potential wartime carrier operations. One of these plans, devised in the 1930s, involved a surprise strike against the Italian battle fleet based at Taranto harbor in southern Italy: A carrier force would approach at night, launch torpedo bombers, and sink the Italian battleships at their moorings.
The opportunity to implement the plan came soon after the Italian declaration of war on Great Britain (in June of 1940) and the fall of France (later that summer). Despite the highly aggressive efforts of the British Mediterranean Fleet under their legendary commander, Fleet Admiral Sir Andrew Cunningham, the fleet was in trouble from the start. It was outnumbered and split by Fascist Italy, since the Italian peninsula more or less bisects the Mediterranean. By the fall of 1940, Italy had six modern battleships, while Cunningham only commanded a pair. His only real advantages were a few ships equipped with radar, the British intelligence ability to read Axis cryptographic (code and cipher) traffic, and a pair of aircraft carriers-the old Eagle and the brand-new armored deck flattop HMS Illustrious. Doing what he could to make the odds more even, Cunningham ordered his staff to plan a carrier aircraft strike on the Italian fleet base at Taranto. Though they had no real-world experience to work from, and only sketchy data from old fleet exercises about how to proceed, with typical British aplomb they began training aircrews and modifying their aerial torpedoes so they would run successfully in the shallow water of Taranto Harbor. Meanwhile, a special flight of Martin Maryland bombers began regular reconnaissance of Italian fleet anchorages. By November of 1940, they were ready to go with Operation Judgment.
Though the original Operation Judgment plan called for almost thirty Swordfish torpedo bombers from both Eagle and Illustrious, engine problems with Eagle and a hangar fire on Illustrious cut that number considerably. In the end, only Illustrious, along with an escort force of battleships, cruisers, and destroyers, set out to conduct the attack. On the night of November 11th, Illustrious and several escorting cruisers broke off from the main force, and made a run north into the Gulf of Taranto. Later that night, Illustrious launched a pair of airstrikes using twenty-one Swordfish torpedo bombers (only a dozen of which carried the modified shallow-water torpedoes). The two strikes sank three of the six Italian battleships then in port and damaged several smaller ships and some shore facilities.[10] In just a few hours, the brilliantly executed strike had cut the Italian battleship fleet in half, and changed the balance of naval power in the Mediterranean.
7
Battle cruisers, a British invention, combined a large hull and power plant with a battleship's armament. While as fast as a cruiser (twenty-five-plus knots) and as heavily armed as a battleship, they lacked the armor protection of a traditional dreadnought. This made them vulnerable to enemy fire in a gunnery duel, though they could normally run away from a stock battleship.
8
The "5:5:3 ratio" represented the allowable naval tonnage under the treaty for the U.S., Great Britain and Japan respectively. The treaty held until the 1930s, when the run-up to World War II began.
9
Though it would be two decades before practical experience would prove it, the single most important characteristic of carrier design is aircraft capacity. No other factor, including speed, antiaircraft armament, or armor protection is so desirable as the ability to carry and operate lots of aircraft. The British found this out the hard way, when they sacrificed aircraft capacity for armor protection in their
10
Of the three battleships that sank to the bottom of Taranto Harbor, the