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Illustrious Class, British Fleet Carriers


Photograph of Illustrious

U.S. Office of Naval Intelligence. Via AcePilots.com


Specifications:


Tonnage 23,000 tons standard displacement
Dimensions 743'9" by 95'9" by 24'
226.70m by 29.18m by 7.32m
Maximum speed    
30.5 knots
Complement 1200
Aircraft 740' (225.5 m) flight deck
2 elevators
1 catapult
36 aircraft
Armament 8x2 4.5"/45 dual-purpose guns
48 40mm/40 AA guns
Protection 4.5" (114mm) belt, bulkheads, and hangar sides
3" (76mm) flight deck
3" (76mm) hangar floor
3" (76mm) steering
1.5" (38mm) torpedo holding bulkhead
13'5" (4.1m) torpedo protection depth designed against 750 lb (340kg) TNT
Machinery
3-shaft Parsons geared turbine (111,000 shp)
6 Admiralty 3-drum boilers
Bunkerage 4850 tons fuel oil
50,540 gallons (191,310 liters) aviation gasoline
Range 11,000 nautical miles (20,000 m) at 14 knots
Sensors
Type 281 air search radar
Type 285 fire control
Modifications
Light antiaircraft armament continually increased, reaching 50 20mm AA guns and 21 40mm Bofors AA guns on some units by 1945.

Deck parking was adopted to increase capacity to 54 aircraft.

Radars were continually upgraded, eventually including Type 277 height-finder and Type 960 air search.

Complement rose to about 2000 by 1945.


The Illustrious class was built under the limitations of the Second London Treaty, which restricted carrier displacement to 23,000 tons. Faced with inevitable tradeoffs, the British focused on the likelihood that their carriers would have to operate under constant risk of land-based air attack. This led to a novel design philosophy emphasizing armor protection of her aircraft against bombs and cruiser fire. The hangar deck was a heavily armored box merging with substantial side armor belts, the only weaknesses being the unarmored elevators.

The heavily armored flight deck allowed these ships to shrug off kamikaze strikes that would have crippled an American carrier. However, the tradeoff for this substantial protection was a rather small air group for a class that was intended to be the backbone of the fleet air arm.


Units in the Pacific:

Illustrious     
Arrived 1942-5
Withdrawn 1943
Arrived early 1944     
Victorious     
Arrived 1943-2 (Pearl Harbor)
Withdrawn 1943-8
Arrived 1945-4
Formidable     
Arrived 1942-3
Withdrawn 1942-10
Arrived autumn 1944



References

Chesneau (1992)

Gogin (2010; accessed 2012-12-24)

Worth (2001)



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