- Illustrious class aircraft carrier
The "Illustrious" class was a class of
aircraft carrier of theRoyal Navy that were some of the most important British warships inWorld War II (WWII). They were laid down in the late1930s as part of therearmament of British forces in response to the emerging threats ofNazi Germany , Fascist Italy andImperial Japan .Each of these ships played a prominent part in the battles of WWII. "Victorious" took part in the chase of the German battleship "Bismarck", "Illustrious" and "Formidable" played prominent parts in the battles in the Mediterranean during 1940 and 1941 and all three took part in the large actions of the
British Pacific Fleet in 1945.The "Illustrious" class comprised four vessels: HM Ships "Illustrious", "Formidable" and "Victorious". "Indomitable" was built to a slightly modified design with a second half-length hangar deck below the main hangar deck. The following two ships of the "Implacable" class were also built to modified designs in order that they could carry larger air wings. HMS|Implacable|R86|2 and HMS|Indefatigable|R10|2, had two hangar levels, albeit with a limiting convert|14|ft|m|0 head room.
Design and concept
The "Illustrious" class was designed within the restrictions of the
Second London Naval Treaty , which limited carrier size to an upper limit of 23,000 tons. They were different in conception to the Royal Navy's only modern carrier at the time, their predecessor HMS "Ark Royal", and what may be described as their nearest American contemporaries, the "Yorktown" and "Essex" class carriers. The "Illustrious" class followed the "Yorktown" but preceded the "Essex".Where other designs emphasised large air groups as the primary means of defence, the "Illustrious" class relied on their anti-aircraft armament and the passive defence provided by an armoured flight deck for survival; resulting in a reduced aircraft complement. Other carriers had armour carried on lower decks (e.g the hangar deck or main deck); the unprotected flight deck and the hangar below it formed part of the
superstructure , and were unprotected against even small bombs. However, the hangar could be made larger and thus more aircraft could be carried.In the "Illustrious" class, armour was carried at the flight deck level—which became the strength deck—and formed an armoured box-like hangar that was an integral part of the ship's structure. However, to make this possible without increasing the displacement it was necessary to significantly reduce the size and headroom of the hangar. The later three vessels, "Indomitable", "Indefatigable" and "Implacable", had re-designed two-level hangars which enabled them to carry larger air groups than the original design. The size of the air wings was also increased by using outriggers and deck parks. The original design was for 36 aircraft, but eventually the vessels operated with a complement of up to 72 aircraft. However, the smaller overhead height of the hangars (16 ft (4.88 m) in the upper hangars and 14 ft (4.27 m) in the later ships with lower hangars) compared unfavourably to the 17 feet 3 inches (5.3 m) of the "Essex" class, 17 ft 6 inches (5.38 m) in "Enterprise" and 20 ft (6.10 m) in "Saratoga". This restricted operations with larger aircraft designs, particularly post-war.
This armour scheme was designed to withstand 1,000 pound bombs (and heavier bombs which struck at an angle); in the Home and Mediterranean theatres it was likely that the carriers would operate within the range of shore-based aircraft. The flight deck had an armoured thickness of 3 inches, closed by 4.5-inch sides and bulkheads. There were 3-inch strakes on either side extending from the box sides to the top edge of the main side belt, which was of 4.5 inches. The main belt protected the machinery, petrol stowage, magazines and aerial weapon stores. The lifts were placed outside the hangar, at either end, with access through sliding armoured doors in the end bulkheads.
Later in the war it was found that bombs which penetrated and detonated inside the armoured hangar could cause structural deformation, as the latter was an integral part of the ship's structure.
The armament was the same as the "Ark Royal", with twin 4.5 inch countersunk turrets arranged on the points of a quadrant. As the ship's own firepower, rather than its aircraft, was relied upon for protection, the guns were mounted sufficiently high so that they could fire across the decks; de-fuelled aircraft would be stowed in the hangar for protection during aerial attack.
Fate of the class
"Illustrious" and "Formidable" did not long survive WWII. Like their contemporary USS|Enterprise|CV-6|6 they had fought a long and consuming war and were worn out; overhaul and renovation would have cost more than replacement. They were broken up for scrap in the 1950s. The last of the class, "Victorious", had a long postwar career with a very expensive reconstruction to enable her to operate
Cold War -era jet aircraft, and retired in 1968 after a fire. "Indomitable" suffered a hangar deck gasoline explosion in 1950 which caused severe damage; she lingered in reserve until after Queen Elizabeth II's Coronation Review and was then scrapped.References
ee also
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