3 THE BIG CONVERSIONS
Limited post-war funding and the Washington Naval Treaty, signed in 1922, forced the RN to retain its small prototype carriers for too long. New ships could not be afforded until 1935, when the new Ark Royal was laid down. Both the USA and Japan were initially better placed, since they had large incomplete battle-cruiser hulls under construction that Treaty rules allowed them to convert into aircraft carriers.
Thus Lexington and Saratoga gave the USN a big increase in the number of aircraft that could operate with its fleets when they were completed. Both were capable of 33 knots. At first the USN thought that they were actually too big, but their air groups quickly demonstrated the value of numbers, and they coped well with the larger aircraft that entered service after 1930.
Japan gained a similar advantage from Akagi and Kaga, the former converted from a battlecruiser and capable of 31 knots. Kaga was converted from a slightly smaller battleship as a replacement after Akagi’s sistership, Amagi, was damaged by an earthquake in 1923 when she was on the slipway. Kaga was capable of only 27.5 knots.
The sole French carrier of, another battleship conversion, which was capable of 21.5 knots. She could embark 40 aircraft, of which 15 were usually kept dismantled in a lower hangar as spares.
