Editing Courageous-class aircraft carrier (section)

== Conversions ==
[[File:HMS Furious-2.jpg|thumb|left|''Furious'' as she was during the First World War with separate take-off and landing decks and superstructure in between]]
[[File:100 years of the RAF MOD 45163717.jpg|thumb|left|A [[Sopwith Pup]] unsuccessfully attempting to land on ''Furious''{{'}}s forward flight deck, 7 August 1917]]
{{HMS|Furious|47|2}} had been fitted during the First World War with a flying-off and landing deck, but the latter proved largely unusable because of the strong air currents around the superstructure and exhaust gases from the funnel. She was laid up after the war, but was converted to an aircraft carrier between June 1921 and September 1925. Her design was based on the very limited experience gained with the first two British carriers: {{HMS|Argus|I49|2}}, less than three years old, and {{HMS|Eagle|1918|2}}, which had carried out only 143 deck landings during preliminary [[sea trial]]s in 1920.<ref>Burt 2012, pp. 263–267</ref><ref>Burt 2012, p. 252</ref><ref>Brown, p. 252</ref>

''Furious''{{'}}s superstructure, masts, funnel and landing deck were removed and she was given a {{convert|576|by|92|ft|m|1|adj=on}} flight deck that extended over three-quarters of her length. This flight deck was not level; it sloped upwards about three-quarters of the way from the stern to help slow down landing aircraft, which had no brakes at the time it was designed. That era's fore-and-aft [[arresting gear]], initially {{convert|320|ft|1}} long on ''Furious'', was not intended to stop landing aircraft—the landing speeds of the time were low enough that this was unnecessary given a good headwind—but rather to prevent aircraft from veering off to one side and potentially falling off the flight deck. Various designs for the flight deck were tested in a wind tunnel by the [[National Physical Laboratory (United Kingdom)|National Physical Laboratory]] which showed that the distinctive elliptical shape and rounded edges minimised turbulence. To minimise any turbulence over the flight deck, ''Furious'' was flush-decked and lacked an island, like ''Argus''; instead she was provided with a retractable [[Glossary of nautical terms (A-L)#charthouse|charthouse]] at the forward end of the flight deck.<ref>Friedman, pp. 93–95</ref>

A two-[[storey]] hangar was built under the flight deck, each level being {{convert|15|ft|1|abbr=on}} high. The lower hangar was {{convert|550|ft|1|abbr=on}} long by {{convert|35|-|50|ft|1|abbr=on}} wide and the upper was {{convert|520|by|50|ft|1|abbr=on}}. Each hangar could be sectioned off by electrically operated steel shutters on rollers. Her boilers were ducted down the side of the ship to exhaust either out of gratings at the rear of the flight deck, or, when landing operations were in progress, out of the side of the lower hangar at the rear of the ship. This solution proved to be very unsatisfactory as it consumed valuable space, made parts of the lower hangar unbearable and interfered with landing operations to a greater or lesser degree. Her original flying-off deck remained in place for use by small aircraft like [[Fighter aircraft|fighters]] so that the ship could simultaneously land aircraft on the main flight deck while fighters were taking off on the lower deck and could speedily launch her aircraft from both decks. Doors at the forward end of the upper hangar opened onto the lower flying deck.<ref>Burt 2012, pp. 264–265</ref> Two {{convert|47|by|46|ft|m|adj=on|1}} lifts (elevators) were installed to transfer aircraft between the flight deck and hangars. Two {{convert|600|impgal|l USgal|adj=on}} ready-use [[petrol]] tanks were provided for aircraft and the ship's boats on the upper deck. An additional {{convert|20000|impgal|l USgal}} of petrol were in bulk storage. The longitudinal arresting gear proved unpopular in service and it was ordered removed in 1927 after tests aboard ''Furious'' in 1926 had shown that deck-edge palisades were effective in reducing cross-deck gusts that could blow aircraft over the side.<ref>Friedman, pp. 94–95</ref> ''Furious''{{'}}s long exhaust ducting hampered landing operations, and restricted the size of the hangars and thus the number of aircraft that she could carry.<ref name="Friedmanpp">Friedman, pp. 103, 105–106</ref>

''Glorious'' and ''Courageous'' were converted to aircraft carriers after ''Furious'' began her reconstruction, ''Courageous'' at [[HMNB Devonport|Devonport]] starting on 29 June 1924, and ''Glorious'' at [[Rosyth]] on 14 February 1924. The latter was moved to Devonport to complete the conversion after ''Furious'' was finished. Their design was based on ''Furious'' with a few improvements based on experience gained since she was designed. All superstructure, guns, and fittings down to the main deck were removed. A two-storey hangar, each level {{convert|16|ft|1|abbr=on}} high and {{convert|550|ft|m|1|abbr=on}} long, was built on top of the remaining hull; the upper hangar level opened onto a short flying-off deck, below and forward of the main flight deck. Two slightly larger {{convert|46|by|48|ft|m|adj=on|1}} lifts were installed fore and aft in the flight deck. An island was added on the starboard side with the bridge, flying control station, and funnel, as an island did not create as much turbulence as had been earlier feared. By 1939 both ships could carry {{convert|34500|impgal|l USgal}} of petrol.<ref name="Friedmanpp" />