The County class was a class of British guided missile destroyers, the first such warships built by the Royal Navy. Designed specifically around the Seaslug anti-aircraft missile system, the primary role of these ships was area air defence around the aircraft carrier task force in the nuclear-war environment.Purvis, M.K., 'Post War RN Frigate and Guided Missile Destroyer Design 1944–1969', Transactions, Royal Institution of Naval Architects (RINA), 1974Marriott, Leo: Royal Navy Destroyers since 1945, , Ian Allan Ltd, 1989
Eight ships were built and entered service. Two served in the British naval task force in the Falklands War in 1982. After leaving British service, four ships were sold to the Chilean Navy and one to the Pakistan Navy.
Development A class of ten ships was envisaged in 1958 for about £6–7.5 million each,G. Moore. Daring to Devonshire in Warship 2006. Conway Maritime. (London) p124, 130 equivalent to a costed Programme for four large, Seaslug-armed, 15,000-ton cruisers, estimated at £14 million each, based on an upgraded Minotaur-class cruiser (1951), approved for full design in early 1955. The final four County-class ships, with hull numbers 07 to 10, were delayed in 1960 while an anti-submarine escort carrier was considered. Hulls 07 and 08 were approved in 1963 as a temporary stopgap,ADM 167 162 1963 and the ninth and tenth hulls were cancelled.
The class was designed as a hybrid cruiser-destroyer with dimensions similar to the broad-beam 1951 Dido class.1/ADM22760:1951 Emergency War Programme, Gun armament (PRO) Much larger than predecessors such as the 2,800 ton . the new County class would be destroyer-leaders for aircraft carrier task forces and when operating "East of Suez" also play a traditional cruiser flagship role with shore bombardment, and attacking enemy shipping. In 1955 the new First Sea Lord Louis Mountbatten specified the development of 4,800 ton Fast fleet escort design (DNC 7/959) with a Seaslug missile replacing a stern twin 3-inch anti-aircraft mounting,. This replacing a 15,000 ton cruiser design which would have combined Seaslug with the Type 984 3D radar and a conventional Tiger-class gun armament. John Coates, RCNC was appointed as naval architect to design the new County class destroyer in accordance with Lord Mountbatten's directive. He wrote that:"To keep the ship to a size responding to Lord Mountbatten's directive, demand by specialist interests within the Admiralty had to be strictly controlled, and often curtailed." During 1956–1958 a full "alternative" gun armament was an option for the new Fast Escort for the fleet based on a modern combined gas turbine and steam turbine (COSAG) propulsion unit and armed with two twin 4.5-inch guns, two twin 40 mm Bofors and a single twin 3-inch gun. A detailed March 1957 study following the Suez Crisis and the 1957 Defence White Paper decided to increase the size of the new missile destroyers to that of light cruisers and include some cruiser featuresDNC 7/1014 for Board of Admiralty & ADM 167/150:1957Brown & Moore. 2012, p 37=8. The study opted for a long hull with a fit of 18 Seaslug and four nuclear warhead fitted Seaslug for extended range anti-aircraft, anti-missile and anti-ship.DNC 7/1014 Twin 40 mm Bofors were kept due to doubt over the future and effectiveness of the "Green Light" missile then under development. The Limbo mortar was the only anti-submarine weapon.
A revised design in March 1958 added Seaslug and Seacat missiles and a telescoping aircraft hangar. Mountbatten staged an impressive demonstration shoot for flag officers and politicians: the Seaslug test ship HMS Girdle Ness launched ten Seaslugs, including a salvo of two Seaslugs together. The success included hits in the lethal zone of two piston-engine Fairey Firefly radio-controlled drones at flying at a speed of 315-375 mph. This enabled the Minister of Defence Duncan Sandys to gain the approval of the Cabinet Defence Committee for Seaslug production to be approved in 1958.:PRO. ADM 205/172 1958, (26) p. 211
While the missile worked against level flying targets, the beam guidance system was dubious at range and in rough water and eight fixed stabilisers were added to the design of the County-class. Advocacy for the guided missiles fit was led by Mountbatten and the Cabinet agreed with using the system, despite staff reports over missile unreliability and inaccuracy,. This was confirmed by the dismal performance in the following Seaslug target launches at Woomera range, South Australia in 1959 Many Royal Australian Navy officers felt Seaslug was unsuitable for the RAN.
Final revisions to the design in 1958ADM 167 152 1958 and First Lords Record (Public Record Office)- the final, construction order, ship cover and legend no longer exist were to adopt a high flush deck from B turret, increasing internal space, the cancellation of the nuclear-tipped Seaslug, and provision for folding fins for the Seaslug; this allowed storage of 20 extra missile bodies which could be rapidly assembled. Against staff advice, a tight fitting, fixed side-hangar for the anti-submarine Westland Wessex helicopter was added on the insistence of the First Sea Lord. While a flawed layout, it proved usable when tested in the Falklands War in 1982.
Lord Mountbatten classified the County-class as guided missile destroyers with cruisers discredited in the media as colonial relics, obsolete gunships like battleships. The Royal Navy staff and officers regarded the County class as cruisers, and to signify that they were major surface units, they were given names previously carried by cruisers including the preceding County-class heavy cruisers and First World War armoured cruisers. The County-class differed from cruisers, as these ships were unarmoured and fitted to destroyer standards, except for staff accommodation and a short ranged, semi automatic, 4.5 destroyer armamentD.K. Brown. Century of Naval Construction. History of Royal Corps of Naval Constructors. Conway Maritime. London (1983)C.J Bartlett. The Long Retreat. A Short History of British Defence Policy 1945-70. Macmillan (1972) & Palgrave (2014) given additional spotting radar. They did provide space and weight for light Bofors and Oerlikons to be fitted if required. The apparently impressive performance of Seaslug against jet Gloster Meteor UC15 drones gave the Royal Navy a number of County-class 'destroyers' and a greater number of ship commands and posts for ambitious officers.
While short on the support and logistic spares stocks of a traditional cruiser, they were envisaged by the Director of Naval Construction as being 'probably' used in the cruiser role with space for Flag staff offices, and admiral's barge accommodation in the 1960s: the last decade when the UK oversaw significant colonial territory East of Suez. Its missile capability had been overtaken by aircraft development by 1962–63, when HMS Devonshire and Hampshire entered service, but in the early and mid-1960s the modern lines of these guided-missile destroyers, with their traditional RN cruiser style and their impressive-looking missiles, enabled the overstretched Royal Navy to project sufficient power to close down the threat of a militant, left-leaning Indonesia to Malaysia and Borneo during the Indonesia-Malaysia confrontation. Indonesia was not impressed and spent the early 1960s building up an anti-carrier force of Tupolev Tu-16 bombers armed with KS-1 Komet cruise missiles, the very combination Seaslug could not catch.
Seaslug missile
The County class was designed around the GWS1 Seaslug beam riding anti-aircraft missile system. Seaslug was a first-generation surface-to-air missile intended to hit high-flying nuclear-armed bombers and surveillance aircraft like the Tupolev Tu-16 "Badger" and Tupolev Tu-95 "Bear", which could direct strikes against the British fleet from missile destroyers and cruise missile-armed submarines. The Tu 95 and the improved Tupolev Tu-142 were demanding targets for a missile like Seaslug; the long-range Soviet turboprop aircraft flew at an altitude of , at Gunston, B. The Encyclopedia of Russian Aircraft, 1875–1975. Motorbooks International, (rep Osprey, Reed, ed), WI, USA (2005) p. 425. and were barely within the engagement capability of Seaslug. In 1956 during the first integrated trials of Sea Slug on HMS Girdle Ness cancellation of Seaslug was considered. The RAF found Seaslug could not cover low and high level targets and was only marginally capable on subsonic targets at 3–10 miles and height of 1–7 miles, and not effective against modern V Bomber, English Electric Canberra and Soviet Il-28 type aircraft which were likely to be used in a 1956 Suez confrontation. The missile was obsolete in many Admirals and MPs views compared the USN Terrier missile, the RAF Bristol Bloodhound and the British Army's Thunderbird semi-active homing missiles in service by 1958. CNS, Mountbatten and Vice Admiral Reid, saw it as 'deplorable' that Sea Slug was so far behind due to the lack of engineers and higher priority for Korea but it was essential to Royal Navy and UK credibility and independence to continue with Sea Slug. A new British missile or adoption of the Terrier Mk11 or Thunderbird would take too long. The improved Mark 2 version of Seaslug had 10,000 ft (3000 m) greater altitude and speed.
The Seaslug system was a large weapon. Each missile was long and weighed two tons; its handling arrangements and electronics systems were also large; so even fitting a single system aboard a ship the size of the Counties was a challenge. The missiles were stowed horizontally in a long unarmoured magazine which was sited above the waterline and took up a great deal of internal space. The risk of fire near the magazine was checked by an automatic sprinkler system. In order to increase the number of missiles that could be carried, on the last four ships, some of the missiles were stored partly disassembled in the forward end of the magazine. Their wings and fins would be reattached before being moved into the aft sections of the handling spaces and eventually loaded onto the large twin launcher for firing.
The limitations of the beam riding guidance method and lack of a homing head, meant the Mk 1 and 2 Seaslug were intended to have nuclear variants - the much larger blast compensating for lack of accuracy. However nuclear warhead for Mk 1 Seaslug (for the first group of ships) was dropped as it needed extra crew, space and security which were not available on the smaller hull; development of the nuclear warhead for Seaslug on the second group of ships was cancelled in June 1962, to reduce the naval budget, and the RNs requirement below 334 tactical nuclear warheads.