Sea Cat GWS-20 series missile
|Place of origin||United Kingdom|
|Used by||See operators|
|Wars||1971 Indo-Pakistani War
South African Border War
|Warhead||40 lb (18 kg) continuous-rod warhead|
|Engine||2 stage motor|
|CLOS and radio link|
Sea Cat was a British short-range surface-to-air missile system intended to replace the ubiquitous Bofors 40 mm gun aboard warships of all sizes. It was the world's first operational shipboard point-defence missile system and was designed so that the Bofors guns could be replaced with minimum modification to the recipient vessel and (originally) using existing fire-control systems. A mobile land-based version of the system was known as Tigercat.
Sea Cat was designed by Short Brothers of Belfast for use against fast jet aircraft that were proving to be too difficult for the WWII-era Bofors guns to successfully intercept. The missile was based on the Shorts Green Light prototype, itself a development of the SX-A5, a research missile based on the Australian Malkara anti-tank missile to test radio manual guidance of a short-range surface-to-air missile. It replaced the Orange Nell development programme for a lighter weapon than the enormous Sea Slug missile. The first public reference to the name Seacat was April 1958, when Shorts was awarded a contract to develop a close-in short-range air-to-air missile. The missile was shown for the first time to the general public at the 1959 Farnborough Air Show. The first acceptance trials of the Seacat on a warship was in 1961 aboard HMS Decoy. The Seacat became the first operational guided missile to be fired by a warship of the Royal Navy. Later it was adopted by the Swedish Navy, making it the first British guided missile to be fired by a foreign navy.
Sea Cat is a small, subsonic missile powered by a two-stage solid fuel rocket motor. It is steered in flight by four cruciformly arranged swept wings and is stabilised by four small tail fins. It is guided by command line-of-sight (CLOS) via a radio-link; i.e., flight commands are transmitted to it from a remote operator with both the missile and target in sight.
All Sea Cat variants used a common 4-rail, manually loaded, trainable launcher that incorporated the antennae for the radio command link. All that was required to fit the system to a ship was the installation of a launcher, the provision of a missile handling room and a suitable guidance system. Sea Cat was widely used in NATO and Commonwealth navies that purchased British equipment and has been used with a wide array of guidance systems. The four systems used by the Royal Navy are described below.
This was the initial system, which was intended to replace the twin 40 mm Bofors Mark V gun and its associated fire-control systems. The original director was based on the STD (Simple Tachymetric Director) and was entirely visual in operation. The target was acquired visually with the missile being guided, via a radio link, by the operator inputting commands on a joystick. Flares on the missile's tail fins aided identifying the missile. The more advanced CRBF (Close Range Blind Fire) director equipped with spin-scanning radar Type 262 for automatic target tracking could also be used.
GWS-20 was trialled on board HMS Decoy, a Daring class destroyer, in 1961; it was subsequently removed. It was carried in active service by, amongst others, the Fearless class landing ships and the Type 81 Tribal, updated Type 12 Whitby, Type 12I Rothesay and (originally) County class escorts. It was originally intended that all C class destroyers should receive it and the class were prepared accordingly. In the event only HMS Cavalier and HMS Caprice received it, in 1966 refits.
GWS-21 was the Sea Cat system associated with a modified Close Range Blind Fire analogue fire control director (CRBFD) with Type 262 radar. This offered manual radar-assisted (Dark Fire) tracking and guidance modes as well as 'eyeball' visual modes. It was carried as the design anti-aircraft weapon of the Type 81 Tribal class frigate and on the first four County class destroyers.
GWS-22 was the Sea Cat system associated with the full MRS-3 fire control director with Type 903 radar and was the first ACLOS-capable (Automatic, Command Line-Of-Sight) Sea Cat. It was fitted to most of the Leander, Rothesay and County class escorts as they were refitted and modified in the 1970s, as well as the aircraft carrier HMS Hermes. It could operate in automatic radar-guided (Blindfire), manual radar-guided, manual CCTV-guided or, in an emergency, 'eyeball' guided modes. It saw active service in the Falklands onboard all these classes.
The final Royal Navy Sea Cat variant, this used the Italian Alenia Orion RTN-10X fire control system with Type 912 radar and was fitted only to the Type 21 frigate. This variant saw active service in the Falklands.
A land-based mobile version of Sea Cat based on a three-round, trailer-mounted launcher towed by a Land Rover, and a second trailer carrying the fire control equipment. Tigercat was used exclusively within HM Forces by 48 Squadron RAF Regiment between 1967 and 1978 with 12 Launcher Units, being replaced in service by Rapier. Tigercat were also operated by Argentina, India, Iran, Jordan, South Africa and Qatar. Argentina deployed it operationally during the Falklands conflict. No kills or any kind of success were initially believed to have been achieved by the marine-manned Tigercats, but according to more recent work a Tigercat missile scored a near-miss on 12 June, which scored substantial damage to RAF Harrier XW 919, spraying the local powerhouse roof with shrapnel and leaving the aircraft with category 4 damage.
Sea Cat became obsolete due to increasing aircraft speed and the introduction of supersonic, sea-skimming anti-ship missiles. In these cases, the manually guided subsonic Sea Cat was totally unsuited to all but head-on interceptions and then only with adequate warning. A Sea Cat version was tested for intercepting targets flying at high speed near the water surface. This version used a radar altimeter, which kept the missile from being guided below a certain altitude above the surface and hence prevented the operator from flying the missile into the water. This version was never ordered.
Despite being obsolete, Sea Cat was still widely fielded by the Royal Navy during the Falklands war. Indeed, it was the sole anti-aircraft defence of many ships. However, unlike the modern and more complex Sea Dart and Sea Wolf systems, Sea Cat rarely misfired or refused to respond, in even the harshest conditions. It was capable of sustained action, which compensated for its lack of speed, range and accuracy; and, more importantly, it was available in large numbers.
One confirmed "kill" of an Argentine aircraft is directly attributed to this missile from over 80 launches, when on the 25 May HMS Yarmouth shot down an A-4C Skyhawk (C-319USN pic) flown by Teniente Tomás Lucero. Lucero ejected and was recovered by HMS Fearless.
After the Falklands conflict, a radical and urgent re-appraisal of anti-aircraft weaponry was undertaken by the Royal Navy. This saw Sea Cat rapidly removed from service and replaced by modern weapons systems such as Goalkeeper CIWS, more modern 20 mm and 30 mm anti-aircraft guns and new escorts carrying the Sea Wolf missile, including the vertical launch version.
The missiles were fitted to the four Swedish Östergötland-class destroyers, replacing three Bofors L/70 guns (a more modern and heavier variant than the Royal Navy's L/60) with a single launcher on each ship. The Östergötland-class destroyers, which were of late 1950s origin, were retired in the early 1980s.
Sea Cat was mounted on all six "River"-class destroyer escorts of the Royal Australian Navy and was removed from service when the final ship of this class was decommissioned in the late 1990s. In their final variant, fire control was provided by a GWS-21 guidance system supported by a Mk 44 fire control computer. Secondary firing positions based on visual tracking of the target through binoculars mounted on a syncro-feedback mount was also available. HMAS Torrens was the final ship to live fire the system prior to its removal from service; and this was also the only time three missiles were on the launcher and fired in sequence, resulting in one miss and two hits on towed targets.
- Argentine Army
- Argentine Navy, 2 Sea Cat quad launchers installed on the cruiser ARA General Belgrano in 1967
- Argentine Marines, used Tigercat launchers (deployed during Falklands War ), now replaced with RBS 70
- Indonesian Navy now retired
- Imperial Iranian Air Force - Tigercat
- Islamic Republic of Iran Army - Tigercat
- Islamic Republic of Iran Navy - Seacat
- Royal Jordanian Land Force - Tigercat
- Military of Qatar - Tigercat
- Army of Zimbabwe - Tigercat
|Wikimedia Commons has media related to Shorts Sea Cat.|
- "SEACAT - The Guided Missile To Defend Small Ships" FLIGHT International, 5 September 1963, p. 438.
- "SEACAT - The Guided Missile To Defend Small Ships" FLIGHT International, 5 September 1963, p. 437.
- Dean Wingrin. "The Airforce - Weapons - Missiles - Hilda (Tigercat) SAM". SAAE. Retrieved 2008-07-18.
- 5th Infantry Brigade in the Falklands 1982, Nick Van der Bijl, David Aldea, p.205, Leo Cooper, 2003
- Falklands the Air War. Arms & Armour Press. p. 112. ISBN 0-85368-842-7.
- Crucero "General Belgrano" C4 - 1951
- "Hilda (Tigercat) SAM".
- Naval Armament, Doug Richardson, Jane's Publishing, 1981, ISBN 0-531-03738-X
- Modern Combat Ships 5; Type 21, Captain John Lippiett RN, Ian Allan, 1990, ISBN 0-7110-1903-7
- 5th Infantry Brigade in the Falklands, Nicholas Van der Bijl, David Aldea, Leo Cooper, 2003, ISBN 0850529484
- 74 Days: An Islander's Diary of the Falklands Occupation, John Smith, Century, 1984, ISBN 0712603611