The London Treaty defines an aircraft carrier by its specific purpose of carrying aircraft and its ability to launch and recover them. The quoted Washington limits set ordinary carrier displacement at 27,000 tons and gun calibre at eight inches, with 135,000 tons of carriers each for Britain and the United States, 81,000 for Japan, and 60,000 each for France and Italy. Italy secured an allocation but did not field a carrier. Seaplane carriers such as Australia's Albatross and France's Commandant Teste fell outside the carrier tonnage allowance because their aircraft could not land aboard. Carriers existing or building on 12 November 1921 counted as experimental and could be replaced regardless of age within the national ceiling. This applied to Britain's Argus, Hermes, Eagle, and Furious, alongside the American Langley and Japanese Hosho. Later carriers faced a 20-year replacement period, so the experimental category gave Britain flexibility in planning new construction.
Chapter · 2:16:41-2:19:59
Treaty definitions, carrier tonnage, and experimental replacement
Carrier definitions, national tonnage ceilings, and an experimental-ship clause determined which ships counted against treaty limits and when they could be replaced.