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United Kingdom - Royal Navy
Illustrious class Aircraft Carrier


    illustrious class aircraft carrier royal navy hms formidable victorious indomitable


87 HMS Illustrious (1940)
67 HMS Formidable
38 HMS Victorious (1941)
92 HMS Indomitable (1941)
Length: 225,6 meters (740 feet) overall
Beam: 29,2 meters (95 ft 9 in)
Draft: 8,8 meters (28 ft 10 in)
Displacement: 23000 tons (full load)
Speed: 30,5 knots (56 km/h), max.
Range: 10700 NM (19800 km) at 10 knots (19 km/h)
Complement: 1230

3 x geared steam turbines

6 x Admiralty 3-drum boilers
110000 hp (83000 kW)
3 shafts / 3 propellers

full flight deck & hangar for up to 57 aircraft

8 x twin QF 4.5-inch dual-purpose guns
6 xoctuple QF 2-pounder AA guns


The Illustrious class was a class of aircraft carrier of the Royal Navy that included some of the most important British warships in the Second World War. They were laid down in the late 1930s as part of the rearmament of British forces in response to the emerging threats of Nazi Germany, Fascist Italy and Imperial Japan.

The Illustrious class comprised four vessels: HM Ships Illustrious, Formidable, Victorious and Indomitable. The last of these was built to a modified design with a second, half-length, hangar deck below the main hangar deck. Each of these ships played a prominent part in the battles of the Second World War. Victorious took part in the pursuit 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 later two ships of the Implacable class were also built to modified designs in order that they could carry larger air wings. Implacable and Indefatigable both had two hangar levels, albeit with a limited 14-foot (4.3 m) 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, but the differences in aircraft capacity between these carriers and their United States Navy (USN) counterparts is largely due to the USN's operational doctrine, which allowed for a permanent deck park of aircraft to augment their hangar capacity. Illustrious's hangar was 82% as large as USS Enterprise's but Enterprise typically carried 30% of her aircraft capacity in her deck park. Indomitable's two hangars were actually larger than Enterprise's but she carried fewer aircraft because she did not have a large permanent deck park. In 1944/45 RN carriers began to carry a permanent deck park of similar size to their USN counterparts and this increased their aircraft complement from 36 to an eventual 57 aircraft in the single hangar carriers, and from 48 up to 81 in the double hangar, 23,400 ton Implacable design, compared to 90–110 for the 27,500 ton US Essex class.

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 reduce the overhead height of the hangars to 16 ft (4.88 m) in the Illustrious class hangars and 14 ft (4.27 m) in the upper hangar of the Indomitable and 16 ft (4.88 m) in her lower hangar; these 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, which could carry heavier bombs than their carrier-based equivalents. 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 storage, 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.

Pre-war doctrine held that the ship's own firepower, rather than its aircraft, were to be relied upon for protection, since in the absence of radar, fighters were unlikely to intercept incoming attackers before they could release their weapons. Accordingly, the Illustrious class was given an extremely heavy Anti-Aircraft armament. The armament was similar to Ark Royal with twin 4.5 inch turrets (in a new "between-decks" or countersunk design) arranged on the points of a quadrant. 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. The Illustrious Class were fitted with four HACS controlled High Angle Director Towers, for fire control of her 4.5" guns. Illustrious pioneered the use of Radar to vector carrier borne fighters onto attacking or shadowing aircraft, and a Fairey Fulmar fighter from Illustrious achieved the first radar directed kill on 2 September 1940.

source: wikipedia

General characteristics of HMS Victorious (R 38) after refit/reconstruction (1950-57):
Displacement: 35500 tons full load
Length: 781 ft (238 m)
Beam: 103 ft 6 inch (31.5 m) water line, 157 ft (47.8 m) flight deck
Draft: 31 ft (9.5 m)
Machinery: 3 shaft Parsons geared turbines, 6 Foster wheeler boilers
Aircraft: 36
Crew 2400
12 x 3 inch/50 guns (6×2)
6 x 40 mm Bofors (6x1)


87 HMS Illustrious
Builder: Vickers-Armstrongs Shipbuilding, Barrow-in-Furness, Cumbria, UK
Laid down: April 27, 1937
Launched: April 5, 1939
Commissioned: May 25, 1940
Decommissioned: February 1955
Fate: sold for scrap in 1956
67 HMS Formidable
Harland & Wolff Shipbuilding, Belfast, Northern Ireland, UK
Laid down:
June 17, 1937
August 17, 1939
November 24, 1940
August 12, 1947
sold for scrap in 1953
R 38 HMS Victorious
Vickers-Armstrongs Shipbuilding, Wallsend, Tyne & Wear, UK
Laid down:
May 4, 1937
September 14, 1939
May 14, 1941
refit/reconstruction: 1950-57

March 13, 1968
sold for scrap / scrapped 1969
92 HMS Indomitable
Vickers-Armstrongs Shipbuilding, Barrow-in-Furness, Cumbria, UK
Laid down:
10, 1937
Launched: March 26, 1940
October 10, 1941
sold for scrap in 1955 / scrapped


r-87 hms illustrious aircraft carrier royal navy 02
HMS Illustrious (87)

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HMS Illustrious (87)

r-67 hms formidable illustrious class aircraft carrier royal navy 02
HMS Formidable (67)

r-38 hms victorious illustrious class aircraft carrier royal navy 05
HMS Victorious (R 38)

r-38 hms victorious illustrious class aircraft carrier royal navy 04
HMS Victorious (R 38)

r-38 hms victorious illustrious class aircraft carrier royal navy 03
HMS Victorious (R 38)

r-38 hms victorious illustrious class aircraft carrier royal navy 02
HMS Victorious (R 38)

r-38 hms victorious illustrious class aircraft carrier royal navy 06
HMS Victorious (R 38)

r-38 hms victorious illustrious class aircraft carrier royal navy 07
HMS Victorious (38)

r-92 hms indomitable illustrious class aircraft carrier royal navy 02
HMS Indomitable (92)
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