Type 42 destroyer

The Type 42 or Sheffield class, are light guided missile destroyers used by the Royal Navy and the Argentine Navy. The first ship of the class was ordered in 1968 and launched in 1971. Two of the class (Sheffield and Coventry) were sunk in action during the Falklands Conflict of 1982. The UK Royal Navy used this class of destroyer for 38 years between 1975 and 2013.

No ships of this class remain active in the Royal Navy and just one remains in the Argentine Navy. The Royal Navy has replaced them with Type 45 destroyers.

History
The class was designed in the late 1960s to provide fleet area air-defence. In total fourteen vessels were constructed in three batches. In addition to the Royal Navy ships, two more ships were built to the same specifications as the Batch 1 vessels for the Argentine Navy.

HMS Sheffield (D80) and HMS Coventry (D118) were lost in the Falklands Conflict to enemy action. (This was the first conflict when surface warships of the same design have been on opposite sides since World War II, when four Flower-class corvettes built for France in 1939, were taken over by the Kriegsmarine in 1940). The final ship of the class (Edinburgh) decommissioned on 6 June 2013. One Argentine Navy ship (Hercules) remains in service, the other vessel (Santisima Trinidad) sunk whilst alongside in Puerto Belgrano Naval Base in early 2013.

When the Type 82 air-defence destroyers were cancelled along with the proposed CVA-01 carrier by the Labour Government of 1966, the Type 42 was proposed as a lighter and cheaper design with similar capabilities to the Type 82. The class is fitted with the GWS30 Sea Dart surface-to-air missile first deployed on the sole Type 82, HMS Bristol (D23). The Type 42s were also given a flight deck and hangar to operate an anti-submarine warfare helicopter, greatly increasing their utility compared to the Type 82, which was fitted with a flight deck but no organic aviation facilities.

The design was budgeted with a ceiling of £19 million per hull, but soon ran over-budget. The original proposed design (£21 million) was similar to the lengthened 'Batch 3' Type 42s. To cut costs, the first two batches had 47 feet removed from the bow sections forward of the bridge, and the beam-to-length ratio was proportionally reduced. These early, batch 1 Type 42s performed poorly during the contractor's sea trials particularly in heavy seas, and the hull was extensively examined for other problems. Batch 2 vessels (Exeter onwards) embodied better sensors fits, and slight layout modifications. The ninth hull, Manchester, was lengthened in build, as part of an extensive design review. This proved a better hull form at sea and later hulls were built to this specification, although minor equipment and hull layout changes made the remaining ships all unique in their own way. Strengthening girders were later designed into the weather deck structure in the batch 1 and 2 ships, and the batch 3 ships received an external 'strake' to counter longitudinal cracking.

"Mickey Mouse" ears
The first of class, Sheffield, was initially fitted with the odd-looking "Mickey Mouse" ears on her funnel tops which were in fact exhaust deflectors - "Loxton bends" - for the Rolls Royce Olympus TM1A turbine engines, to guide the high-temperature exhaust efflux sidewards and minimise damage to overhead aerials. As this provided a prominent target for the new infra-red homing missiles, these deflectors were removed during Sheffield's 1979–1980 refit in Portsmouth. All subsequent Olympus and Tyne uptakes were fitted with 'cheese graters' which mixed machinery space vent air with the engine exhaust to reduce infra-red signatures.

Remaining Type 42s
The surviving Argentine Type 42, ARA Hercules, is based at Puerto Belgrano, Argentina and has been converted into an amphibious command ship through the addition of a new aft superstructure and hangar. It is also fitted with Exocet missile launchers. The other Argentine vessel, ARA Santísima Trinidad, capsized and sank alongside her berth at Puerto Belgrano on 22 January 2013, reportedly as a result of poor maintenance and negligence leading to a burst seawater main and catastrophic flooding.

Prior to her demise, Santissima Trinidad was extensively cannibalised for spare parts for her more active sister ship.

Design details
The Type 42 destroyer was built to fill the gap left by the cancellation of the large Type 82 destroyer. It was intended to fulfil the same role, with similar systems on a smaller and more cost effective hull. The ships are primarily carriers for the GWS-30 Sea Dart surface-to-air missile system. Although often described as obsolete, it still proved effective against modern missile threats during the 1991 Gulf War.

The Type 42 is also equipped with a 4.5-inch Mark 8 naval gun and earlier vessels shipped six Ships Torpedo Weapon System (STWS) torpedo launchers. Two Vulcan Phalanx Mk 15 Close-In Weapons Systems (CIWS) were fitted to British Type 42s in way of the carried 27-foot whaler and Cheverton launch after the loss of Sheffield to an Exocet missile. There have been three batches of ships, batch 1 & 2 displacing 4,820 tonnes and batch 3 (sometimes referred to as the Manchester class) displacing 5,200 tonnes. The batch 3 ships were heavily upgraded, though the proposed Sea Wolf missile systems upgrades were never fitted. Because of their more general warfare role, both Argentine ships were been fitted with the MM38 Exocet, and not with a CIWS.

The electronics suite includes one Type 1022 D-band long range radar with Outfit LFB track extractor or one Type 965P long range air surveillance radar, one Type 996 E/F-band 3D target indication radar with Outfit LFA track extractor or type 992Q surface search, two Type 909 I/J-band fire control radars and an Outfit LFD Radar Track Combiner.

All ships were propelled by Rolls Royce TM3B Olympus and Rolls Royce RM1C Tyne marinised gas turbines, arranged in a COGOG (Combined Gas or Gas) arrangement, driving through synchronous self-shifting clutches into a double reduction, dual tandem, articulated, locked-train gear system and out through two five-bladed controllable pitch propellers. All have four Paxman Ventura 16YJCAZ diesel generators, each generating 1 Megawatt of three-phase 440V 60 Hz power.

Availability and use of the Type 42
This class was originally conceived to be a stopper for long-range strategic bombers from the former Soviet air force and as area defence for carrier task groups. As world political climates shifted, so too the role of the Type 42 followed. The class reached its operational zenith during the Falklands Conflict with seven ships partaking in Operation Corporate and the immediate aftermath. The Type 42 provided a capable, if limited, long range reach against Argentine air force assets, confirming three kills. With their weaknesses exposed - Sheffield hit, disabled and sunk by a long-range, first generation air-to surface missile, Coventry sunk by conventional (British designed) iron bombs and Glasgow disabled by a single bomb which passed straight through her aft engine room without exploding - an extensive rethink was conducted and future iterations in and out of build and refit contained better upgrades, but limited by the Type 42s now ageing overall design. Later uses involved Gulf War 1, where Gloucester struck and eliminated a large, land-based surface to surface missile with her Seadart missile system. Moreover than not, Type 42s were called upon to carry out Fleet Contingency Ship (FCS) duties, Atlantic Patrol (North) (West Indies counter drugs ops) and Atlantic Patrol (South) (Falkland Islands patrol), Standing Naval Force Mediterranean and Atlantic and Armilla patrols. There was essentially no task this ship class was not engaged in over its forty year collective career. As far as value-for-money is concerned, notwithstanding its ability to burn fifteen tonnes per hour of marine diesel at top speed and a large, cramped ships' company, this ship provided the UK with considerable ability during a very changeable political, economic and military background of change. The deployment of Type 23s in lieu of Type 42s to high-intensity mission areas became more prevalent as serviceability and reliability issues dogged Type 42s availability as has obsolescence of their combat and machinery system equipment. The 2010 Strategic Defence and Security Review (SDSR) sounded a death knell for these venerable warships and they have all been decommissioned and in most cases scrapped.

Construction programme
In May 1982, the Parliamentary Under-Secretary of State (Jerry Wiggin) stated that the current replacement cost of a Type 42 destroyer of the Sheffield class was "about £120 million." In July 1984, the Parliamentary Under-Secretary of State (John Lee) stated: "the average cost of the three Type 42 destroyers currently under construction is £117 million at 1983–84 price levels."

Including refits and upgrades
In May 2000, the Parliamentary Under-Secretary of State (John Spellar) stated: "The running costs of each of the Royal Navy's Type 42 destroyers for each of the past five years are contained in the following table. This includes repair and maintenance, manpower, fuel and other costs such as port and harbour dues. Year-on-year variations are largely attributable to refit periods."

Availability
In February 1998, the Minister of State for Defence, Dr Reid said: "Type 42 destroyers achieved approximately 84 to 86 per cent average availability for operational service in each of the last five years. This discounts time spent in planned maintenance."

Replacement
The UK ships are all now decommissioned. By 2007 none of the batch 1 vessels remained in commission. Initially the UK sought to procure replacements first in collaboration with seven other NATO nations under the NFR-90 project and then with France and Italy through the Horizon CNGF programme. However, both these collaborative ventures failed and the UK decided to go it alone with a national project.

The UK Type 42s are succeeded by six Type 45 destroyers. HMS Daring (D32), HMS Dauntless (D33), HMS Diamond (D34), HMS Dragon (D35) and HMS Defender (D36) are in commission and the other Type 45 HMS Duncan (D37) is currently Accepted off Contract and due to be in service by November 2013. The Type 42 class has always suffered from cramped accommodation, a problem for crew safety and comfort, and also when finding space for upgrades. The Type 45s are considerably larger, displacing 7,500 tonnes, compared to the Type 42 displacement of 3,600 tonnes.