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Implacable-class aircraft carrier
HMS Implacable (R86).jpg
Class overview
Operators:  Royal Navy
Preceded by: Illustrious class
Succeeded by: Audacious class
Completed: 2
Retired: 2
General characteristics

23,460 tons design standard

28,968 tons design full load[1]
Length: 765 ft 9 in (233.40 m)
Beam: 95 ft 9 in (29.18 m)
Draught: 26 ft (7.9 m)
Propulsion: geared steam turbines delivering 148,000 shp (82,000 kW) to four shafts[2]
Speed: 32.5 knots (60 km/h)
Complement: 1,800 including aircrew

8 x 2 QF 4.5-inch (113-mm) dual-purpose guns
6 x 8 2-pdr AA

38 x 20 mm AA guns
Armour: Belt: 4.5 inches (114 mm)
Hangar sides: 1.5 inches (38 mm)
Deck: 3 inches (76 mm)
Aircraft carried: Up to 81 in service, with a permanent deck park

The Implacable class was a class of aircraft carrier employed by the Royal Navy in the second half of the Second World War. The class design was derived from the Illustrious class.


The Implacable-class ships were built some 30 months after the Illustrious-class aircraft carriers. The Implacables were more closely related to the third HMS Ark Royal with hangar walls slimmed down which allowed a better weight distribution. A lower hangar was also introduced in the class. The class also had a fourth set of propulsion machinery which gave them extra speed, similar to the American Essex class. By adopting a permanent deck park, these ships operated up to 81 aircraft while serving with the British Pacific Fleet in 1944 and 1945. These ships used the Fuze Keeping Clock AA fire control system and featured 4 Mk V High Angle Director Towers. The 8 twin turret 4.5" guns on these ships also featured Remote Power Control.


Both ships of the class were laid down in 1939 and launched in December 1942 and were completed in August and May 1944. The delayed build time was due to altered shipyard priorities. Upon completion, the class had a short career.

Indefatigable was a relatively new ship when she achieved the first landing by a twin engined aeroplane, a de Havilland Mosquito. She then joined the British Pacific Fleet. She also took part in air raids against the German battleship Tirpitz.

After the end of the Second World War, both ships were employed in the training role before being scrapped in 1955 and 1956 after hardly a decade of service. The decision to scrap the ships was due to the vast expense of modernising them along the lines of HMS Victorious.

Ships In Class

  • HMS Implacable (R86) (Built by Fairfields in Govan & commissioned August 1944)
  • HMS Indefatigable (R10) (Built by John Brown & Co in Clydebank & commissioned May 1944)



  1. Friedman, p.154.
  2. Friedman, p.154.


  • Brown,D K. Nelson to Vanguard, 2000, Chatham Publishing
  • Bishop, Chris & Chant, Chris. Aircraft Carriers, The World's Greatest Naval Vessels And Their Aircraft.
  • Preston, Antony (2002). The World’s Worst Warships. London: Conway Maritime Press. ISBN 0-85177-754-6. 
  • Ireland, Bernard. The Illustrated Guide to Aircraft Carriers of the World. Hermes House, London, 2005. ISBN 1-84477-747-2
  • Friedman, Norman (1988). British Carrier Aviation: The Evolution of the Ships and Their Aircraft. Annapolis, Maryland: Naval Institute Press. ISBN 0-87021-054-8. 
  • Miller David. The Illustrated Directory of Warships from 1860 to The Present Day, Greenwich Editions, Ed 3, Salamander Books Ltd, London, England, 2004. ISBN 0-86288-677-5.

External links

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