HMS Cavalier (D73) Ca Class Destroyer GWS-20 Sea Cat Missile System Chatham
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.
GWS-20
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-20 saw active service in the Falklands war on board the Fearless class and the Rothesay frigates HMS Plymouth and HMS Yarmouth, who retained the GWS-20 director when upgraded to GWS-22.
GWS-21
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
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.
GWS-24
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.
(Text Wikipedia)
HMS Cavalier (D73) Ca Class Destroyer GWS-20 Sea Cat Missile System Chatham
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.
GWS-20
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-20 saw active service in the Falklands war on board the Fearless class and the Rothesay frigates HMS Plymouth and HMS Yarmouth, who retained the GWS-20 director when upgraded to GWS-22.
GWS-21
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
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.
GWS-24
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.
(Text Wikipedia)