Implacable-class aircraft carrier

The Implacable-class aircraft carrier was a class of two aircraft carriers built for the Royal Navy during World War II. Derived from the design of the Illustrious class, they were faster and carried more aircraft than the older ships. They were initially assigned to the Home Fleet when completed in 1944 and attacked targets in Norway as well as the German battleship Tirpitz. Subsequently they were assigned to the British Pacific Fleet (BPF).

Indefatigable was the first ship to go to the Pacific and attacked Japanese-controlled oil refineries in Sumatra en route. She participated in Operation Iceberg, the invasion of Okinawa in March–April 1945. Implacable's arrival in the Pacific was delayed by a refit and she did not begin operations against the Japanese until June. The sister ships participated in the attacks on the Japanese Home Islands in July and August. Indefatigable was the only carrier chosen to continue operations after most of the BPF withdrew to prepare for further operations in early August. After the Japanese formal surrender in September, Implacable ferried Allied troops and prisoners of war back to Australia and Canada for the rest of the year.

The sisters returned home in 1946; Indefatigable was used for the rest of the year to transport troops before being placed in reserve in 1947 and Implacable became the training carrier for Home Fleet. Indefatigable was converted into a training ship and reactivated in 1950 for service with the Home Fleet. Implacable was relegated to the reserve that same year and modified into a training ship in 1952. The sisters were scheduled for modernisation during the mid-1950s, but it was cancelled as the modernisation of the carrier in the queue ahead of them proved to be too expensive and lengthy. The sisters were decommissioned in 1954 and sold for scrap in 1955–56.

Implacable-class aircraft carrier
Class Ship
Type Aircraft Carrier
Manufacturer Fairfield Shipbuilding and Engineering Company
Production Period 1939 - 1942
Origin United Kingdom - UK (Great Britain)
Country Name Origin Year
United Kingdom - UK (Great Britain) 1944
Country Name Operational Year Retirement Year
United Kingdom - UK (Great Britain) 1944 1956 View
ManufacturerName Production From Production To Quantity
Fairfield Shipbuilding and Engineering Company 1939 1942 1 View
John Brown & Company 1939 1942 1 View


Ships in Class

Name Pennant number Builder Laid Down Launched Completed Fate
HMS Implacable R86 Fairfield Shipbuilding and Engineering Co., Govan, Scotland 21 March 1939 10 December 1942 28 August 1944 Sold for scrap, 27 October 1955
HMS Indefatigable R10 John Brown & Co., Clydebank, Scotland 3 November 1939 8 December 1942 3 May 1944 Sold for scrap, September 1956

Two ships were originally planned, but only one carrier was included in the 1938 Naval Programme as the other was delayed a year by the government. While under construction, the ships had their forward lift enlarged to take non-folding aircraft like the Hawker Sea Hurricane and the early models of the Supermarine Seafire, the flight deck was widened abreast the forward lift, splinter protection was added as were seven diesel generators, each in their own watertight compartment. All these changes increased the ships' displacement by 540 long tons (550 t) at deep load.

Implacable?'?s construction was suspended in 1940 in favour of escorts needed in the Battle of the Atlantic so that the two carriers were launched within days of each other. She embarked portions of her air wing for training in late August and was assigned to the Home Fleet on 7 October at Scapa Flow after working up. She joined ships searching for the Tirpitz a week later and some of her Fairey Fireflies spotted the battleship off Håkøya Island near Tromsø. Subsequently her Fireflies successfully attacked targets in Norway. In late October, the carrier's Seafires arrived and she participated in Operation Athletic off the Norwegian coast, sinking four warships and two merchant ships and damaging a German submarine. In November and December, Implacable provided air cover for minelaying operations and attacked German shipping off the Norwegian coast. On 15 December she began a refit at Rosyth preparatory to her transfer to the BPF, which included augmenting her light AA armament.

When the refit was completed on 10 March 1945, the ship embarked an enlarged air wing with 81 aircraft (48 Seafires, 12 Fireflies, and 21 Grumman TBF Avenger torpedo bombers), the largest number of aircraft aboard a British carrier up to that time. Implacable arrived at Sydney, Australia in May and joined the other carriers of the 1st Aircraft Carrier Squadron (1st ACS) at Manus Island after their return from the invasion of Okinawa in June. On 14–15 June, the carrier attacked the Japanese naval base at Truk. After working up with the other carriers, the ship sailed with the 1st ACS on 6 July to rendezvous with the American carriers of Task Force 38 off the Japanese home island of Honshu ten days later. The British carriers began flying sorties against Japanese targets on Honshu on 17 July and Implacable?'?s aircraft, before departing the area on 11 August to replenish, flew over 1,000 sorties. She arrived at Sydney on 24 August and spent most of the rest of the year ferrying Allied prisoners of war and soldiers back to Australia and Canada. In January 1946, together with her sister Indefatigable and several other ships, she made a number of port visits in Australia and New Zealand. The ship was refitted in Sydney in preparation for her return home on 3 June where she became the deck-landing training carrier for the Home Fleet.

Implacable temporarily became a trials carrier in October 1947 as her own air group was not yet ready and she was refitted from October to December 1948 in preparation of service as the Home Fleet flagship. She embarked a squadron each of de Havilland Sea Hornets and Blackburn Firebrands in April 1949 and became the flagship of Admiral Sir Philip Vian on 29 April. A squadron of de Havilland Sea Vampires flew from her deck later that year and her air group was augmented by a squadron of Fairey Barracudas in 1950. Implacable was placed in reserve in September 1950 and slowly converted into a training ship by the addition of extra accommodation and classrooms, including the addition of a deckhouse on her flight deck. She was recommissioned on January 1952 as the flagship of the Home Fleet Training Squadron. Together with Indefatigable, she was present during the Coronation Fleet Review of Queen Elizabeth II on 15 June 1953. Four months later, Implacable ferried a battalion of troops from Plymouth to Trinidad in response to a crisis in British Guiana. She was decommissioned on 1 September 1954 and sold for breaking up on 27 October 1955.

Operators:  Royal Navy
Preceded by: Illustrious class
Succeeded by: Audacious class
Built: 1939–44
In service: 1944–55
Completed: 2
Scrapped: 2
General characteristics
Class & type: Implacable-class aircraft carrier
Displacement: 32,110 long tons (32,630 t) (deep load)
Length: 766 ft 6 in (233.6 m) (o/a)
730 ft (222.5 m) (waterline)
Beam: 95 ft 9 in (29.2 m)
Draught: 29 ft 4 in (8.9 m) (deep load)
Installed power: 148,000 shp (110,000 kW)
8 Admiralty 3-drum boilers
Propulsion: 4 shafts
4 geared steam turbines
Speed: 32.5 knots (60.2 km/h; 37.4 mph)
Range: 12,000 nmi (22,000 km; 14,000 mi) at 10 knots (19 km/h; 12 mph)
Complement: 2,300 (1945)
Sensors and
processing systems:
1 × Type 277 height-finding radar
1 × Type 279 early-warning radar
1 × Type 281 early-warning radar
6 × Type 282 gunnery radars
4 × Type 285 gunnery radars
Armament: 8 × twin QF 4.5-inch dual-purpose guns
5 × octuple, 1 × quadruple QF 2-pdranti-aircraft guns
18–21 × twin, 17–19 × singleOerlikon 20 mm anti-aircraft guns
Armour: Waterline belt: 4.5 in (114 mm)
Flight deck: 3 in (76 mm)
Bulkheads: 2 in (51 mm)
Hangar sides: 2 in (51 mm)
Magazines: 3–4.5 in (76–114 mm)
Aircraft carried: 81
Aviation facilities: 1 catapult

End notes