Development[ edit ] In the early s, the Washington Naval Treaty imposed limits on the maximum size and total tonnage of aircraft carriers for the five main naval powers. Later treaties largely kept these provisions. As a result, construction between the World Wars had been insufficient to meet operational needs for aircraft carriers as World War II expanded from Europe.
Too few fleet carriers were available to simultaneously transport aircraft to distant bases, support amphibious invasions, offer carrier landing training for replacement pilots, conduct anti-submarine patrols, and provide defensive air cover for deployed battleships and cruisers. Conversion of existing ships and hulls under construction for other purposes provided additional aircraft carriers until new construction became available.
Conversions of cruisers and passenger liners with speed similar to fleet carriers were identified by the U. Slower conversions were classified as "escort carriers" and were considered naval auxiliaries suitable for pilot training and transport of aircraft to distant bases. The Royal Navy had recognized a need for carriers to defend its trade routes in the s. In the interim, before escort carriers could be supplied, they also brought in merchant aircraft carriers that could operate four aircraft.
In , Admiral William Halsey recommended construction of naval auxiliaries for pilot training. Operation Torch and North Atlantic anti-submarine warfare proved these ships capable aircraft carriers for ship formations moving at the speed of trade or amphibious invasion convoys.
It was quickly found that the escort carriers had better performance than light carriers, which tended to pitch badly in moderate to high seas.
