1942 Design Light Fleet Carrier - Design and Construction

Design and Construction

Experiences during the early part of World War II had demonstrated to the British that the Royal Navy needed access to defensive air cover for Allied fleets and convoys, which could only be provided by more aircraft carriers. In mid-1941, the Director of Naval Construction was instructed to investigate how best to achieve this without the lengthy construction times normally associated with carriers. The options were to refit the surviving Hawkins class cruisers with flight decks and aviation facilities, convert additional merchant vessels and passenger liners into vessels similar to but more capable than previous merchant aircraft carriers, or create a new design for a cheap, lightly armed, and unarmoured ship similar to the Woolworth carriers. In December 1941, it was decided that a new design was the best option.

This ship was conceived as an intermediate step between the expensive fleet carriers and the limited-capability escort carriers. The design had to be as simple as possible so construction time was kept to a minimum and so more shipyards (particularly those with no naval construction experience) could be used. However, the ships had to be capable of operating in fleet actions. Originally designated the 'Intermediate Aircraft Carrier', the ships were reclassified as 'Light Fleet Carriers'. Because naval design staff were overworked, the carrier was primarily designed by shipbuilders at Vickers-Armstrong.

The Light Fleet design, completed at the start of 1942, was effectively a scaled-down Illustrious. Each carrier would displace 13,190 tons at standard load and 18,040 tons at full load, have a length of 680 feet (210 m) at the flight deck and 695 feet (212 m) overall, a maximum beam of 80 feet (24 m), and a draught of 18 feet 6 inches (5.64 m) at standard displacement, and 23 feet 6 inches (7.16 m) at full load displacement. The hull was built to Lloyd's specifications for merchant vessels from keel to maindeck, but incorporated better subdivision of compartments to reduce secondary damage by flooding.

The propulsion machinery was of a similar design to that used in cruisers—some of the steam turbines were sourced from cancelled cruisers. The machinery was arranged in two compartments (each containing two Admiralty 3-drum boilers and a Parsons geared turbine), which were staggered en echelon, with the starboard compartment forward of the port. These provided 40,000 shaft horsepower to two propeller shafts, driving the carriers at a maximum speed of 25 knots (46 km/h; 29 mph), with 15 knots (28 km/h; 17 mph) as the designated economical speed.

The carriers were intended to be 'disposable warships': to be scrapped and replaced at the end of World War II or within three years of entering service. However, all exceeded this planned service life, with one ship operating from 1945 to 2001.