"Treaties limiting naval armaments restricted the sizes of warships and guns, but left torpedoes, mines and aircraft uncontrolled. An examination of particulars published concerning capital ships launched since 1915 showed that the percentage of standard displacement absorbed by torpedo protection and anti-destroyer armament had progressively increased. The statements concerning torpedoes could also be applied to mines. Aircraft had improved in performance, were larger, and carried a greater load. Consequently, a greater percentage of the standard displacement of capital ships and cruisers had been absorbed by anti-aircraft armament and protection; also the space and weight necessary for aircraft was increased. The London Naval Treaty of 1936 restricted the main armament of 35,000-ton capital ships to 14-inch guns instead of 16-inch guns but permitted the latter under certain circumstances. Considerations concerning uncontrolled weapons led to the conclusion that the well-balanced 35,000 ton capital ship design should have 14-inch rather than 16-inch guns. Aircraft carriers were restricted to 23,000 instead of 27,000 tons. But naval aircraft had increased in size, therefore a larger number of aircraft carriers were required."