The
Invincible-class is a
class of
light aircraft carrier currently serving with the
British Royal Navy. Of the three vessels of this class, and are in operation, with decommissioned from service and in reserve until 2010.
Development
The
Invincible class has its origins in a sketch design for a 6,000
ton, guided-missile armed, helicopter carrying escort cruiser intended as a complement to the much larger
CVA-01-class fleet aircraft carrier.
[Vanguard to Trident; British Naval Policy since World War II, Eric J. Grove, The Bodley Head, 1987, ISBN 0-370-31021-7] The cancellation of CVA-01 in 1966 meant that the smaller cruiser would now have to provide the
anti-submarine warfare (ASW) taskforce with
command and control facilities. Two new designs were prepared for this requirement;
a 12,500 ton cruiser with missiles forward, six
Westland Sea King helicopters and a flight deck aft, somewhat similar to the
Vittorio Veneto of the
Italian Navy and a larger 17,500 ton vessel with a "through-deck", nine Sea Kings and missiles right forward. By 1970, the "through-deck" design had advanced into a Naval Staff Requirement for an 18,750 ton Through-Deck Command Cruisers (TDCC).
In February 1963, the
Hawker P.1127 VTOL (vertical take-off and landing) aircraft had landed and taken-off from the carrier and the subsequent
Hawker-Siddeley Kestrel had undergone trials from the LPH . It was therefore perfectly possible that the new "cruisers" could be used to operate VTOL aircraft. Politics, however, determined that the new ships were carefully termed "through-deck cruisers" and not "aircraft carrier" by the RN; the cancellation of CVA-01 was intended to mean the UK's abandonment of aircraft carriers for good.
Economic problems in the UK in the early 1970s delayed progress on the new ships, but the design continued to evolve. The order for the first ship was given to
Vickers (Shipbuilding) on 17 April 1973.
[Warships of the Royal Navy, Capt. John E. Moore RN, Jane's Publishing, 1981, ISBN 0-7106-0105-0] By now, the design was for a 19,000 ton "CAH"
(helicopter carrying heavy cruiser, styled after the U.S Navy
Hull classification symbols) with up to fourteen aircraft and a
Sea Dart missile launcher on the bows.
Finally, in May 1975, the Government authorised the maritime version of the
Hawker Siddeley Harrier,
which was successfully developed into the
Sea Harrier. This meant that the design was reworked again to include a small complement of these
VTOL aircraft. In order to launch a heavily-laden Harrier more efficiently by
STOVL (short take-off vertical landing) from the comparatively short - 170 m -
flight deck, a 'ski-jump' was developed. The slope was initially 7° when incorporated into
Invincible and
Illustrious and 12° for
Ark Royal. The class also has, since 1976,
a secondary role as an helicopter carrier, or
LPH, in the reinforcement of NATO's Northern flank in Norway. In 1998 , with a hull form based on that of the
Invincible class, was commissioned specifically for this role.
HMS Invincible in 1991
After the 1982
Falklands War,
CIWS guns were added to the design.
Illustrious had them fitted at the last minute before commissioning,
Ark Royal had them added as a normal part of the building process, and
Invincible had them fitted during her first overhaul after the Falklands. Initially,
Invincible and
Illustrious were fitted with two
Vulcan Phalanx units; these have since been replaced with three
Goalkeeper systems.
Ark Royal has the three
Phalanx CIWS systems she was fitted with when built (she can be easily distinguished from her sisters by the Phalanx's distinctive white "
R2-D2" radome). Electronic countermeasures are provided by a Thales jamming system and ECM system.
Seagnat launchers provide for chaff or flare decoys. As part of upgrades during the mid 1990s, all three ships had the
Sea Dart removed, with the forecastle filled in to increase the size of the flight deck.
Construction Programme
Falklands War
Prior to 1982,
Invincible's air group consisted purely of
Sea King HAS.5 anti-submarine helicopters and
Sea Harrier FRS.1 aircraft. Typically, nine Sea Kings, and four or five Sea Harriers were embarked. This was due to the fact that the originally envisioned mission for the ships was to provide the heart of
ASW hunter-killer groups in the North Atlantic during a war against the
Soviet Union. In that context, the main weapon of the carrier would not be its fighter aircraft, but its ASW helicopters. The fighters were on board to shoot down the occasional Soviet maritime patrol aircraft nosing around the ship and its escorts.
The
Falklands War changed that posture, since it proved that Britain needed to retain the capability to use carrier air power in its traditional role of
power projection, both over land, and against enemy fleets. The Falklands War saw
Invincible, and the larger and older filled to capacity with both the Sea Harrier and the
Royal Air Force Harrier
GR3 ground attack variant of the aircraft, along with ASW helicopters. The RAF Harriers proved to be a temporary aberration at the time. However a permanent addition to the usual air group was made due to lessons learnt during the war: the
Sea King AEW2A (
Airborne Early Warning) version.
Illustrious carried the first examples of the type when it was rushed south in the aftermath of the Falklands War to relieve
Invincible of its guard duty around the islands.
(right) with the nuclear aircraft carrier
In the aftermath of the Falklands, the typical air group was 3 AEW Sea Kings, 9 ASW Sea Kings and 8 or 9 Sea Harriers. Analysis of the Sea Harrier's performance during the war lead to the requirement for an upgrade, approval for which was granted in 1984. Initially to be known as the FRS.2, the
Sea Harrier FA2 entered service on 2 April 1993, deploying on
Invincible to Bosnia in 1994. The FA2 featured the Blue Vixen radar which is described as one of the most advanced pulse Doppler radars in the world. The Blue Vixen formed the basis for the
Typhoon's CAPTOR radar. The FA2 carried the
AIM-120 AMRAAM. The final new-build Sea Harrier FA2 was delivered on 18 January 1999. Other improvements were made to the class during the 1980s and early 1990s, with probably the most important being the increase of the ski jump angle on
Invincible and
Illustrious to match the 12° slope of
Ark Royal.
Modernization
HMS Invincible undergoing overhaul and modernization.
In recent years, three other changes have been made. One was the removal of the Sea Dart system, creating an increased deck park for aircraft. The Sea Dart magazines were converted to increase air-to-surface weapons stowage, and new aircrew briefing facilities created under the extended flight deck, both to support the embarkation of RAF Harrier GR7s as a routine part of the air group. The ships have all also been fitted to handle the new
Merlin helicopters. The
HM1 variant of the Merlin has replaced the
HAS6 variant of the Sea King in the carrier-borne ASW role. Since the integration of the Harrier GR7, typical deployments have included 7 or 8 of those aircraft, pushing the Merlin onto the carrier's escorting
Fort class replenishment ship.
The two most recent wartime deployments of the class have seen them in their secondary LPH role, as it was officially judged that Sea Harriers could provide no useful role in the missions. During those deployments, the class has embarked RAF
Chinook helicopters, in lieu of their fixed wing complement.
Future
The Sea Harrier was officially retired on 1 April 2006. From now until the decommissioning of the ships, their principal weapon will be the
Harrier GR9 flown by two
Fleet Air Arm and two
RAF squadrons.
Invincible was decommissioned in July 2005, and has been mothballed (available for reactivation on notice) until 2010.
Ark Royal has taken over as the Flagship and is planned to be decommissioned in 2015,
Illustrious in 2012, as two new, much larger
Queen Elizabeth class aircraft carriers are brought into service. They are expected to displace around 65,000 tonnes each - more than three times the displacement of the
Invincible class.
Specification
- Displacement: 16,970 tons standard; 20,710 tons full load
- Crew: Ships crew: 650. Air crew: 350. Capacity for additional 500 royal marines
The Paxman Valenta power units used for electrical power generation are similar to the engines originally used in the British Rail Class 43 HST Power cars
Ships in class
HMS Invincible (R05)
right|thumb|200px|Invincible- Launched: 8 May 1977 (List)
- Commissioned: 11 July 1980 (List)
- Decommissioned: 3 August 2005 (List)
- Status: Mothballed (reserve)
HMS Illustrious (R06)
thumb|right|200px|Illustrious- Laid down: 7 October 1976
- Launched: 14 December 1978 (List)
- Commissioned: 20 June 1982 (List)
HMS Ark Royal (R07)
thumb|right|200px|Ark Royal- Laid down: 14 December 1978
- Launched: 2 June 1981 (List)
- Commissioned: 1 November 1985 (List)
- Status: In active service
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