The Seacat was a small, subsonic missile powered by a two-stage solid fuel rocket motor. It was steered in flight by four cruciformly arranged swept wings and was stabilised by four small tail fins. Flight commands are transmitted to it from a remote aimer, manipulating a small joystick, who had both the missile and target in sight through binoculars mounted on a syncro-feedback mount.
A mobile land-based version of the system was known as Tigercat. All Seacat variants used a common 4-rail, manually loaded, trainable launcher that incorporated the antennas for the radio command link.
The first public reference to the name Seacat was April 1958, when Short Brothers of Belfast was awarded a contract to develop a close-in short-range surface-to-air missile. Seacat was designed by Short Brothers 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.
Royal Navy acceptance of Seacat as a point defence system, instead of the Bofors L60 and the more effective Bofors L70 with proximity fused shells, was controversial as many doubted the effectiveness of Seacat. As well as use in point defence against air attack, Seacat was justified as an anti missile system against Styx missiles of the Warsaw Pact navies. It was also justified on its, 'ridiculous simplicity', and ease of maintenance, compared with the Mk 5 Twin Bofors and SAAG type mountings.
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.
Seacat eventually became obsolete due to increasing aircraft speed and the introduction of supersonic, sea-skimming anti-ship missiles. In these cases, the manually guided subsonic Seacat was totally unsuited to all but head-on interceptions and then only with adequate warning. A Seacat 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, Seacat 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, Seacat 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.
After the Falklands conflict, a radical and urgent re-appraisal of anti-aircraft weaponry was undertaken by the Royal Navy. This saw Seacat 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.
Seacat, together with the Ikara ASW system was mounted on all six of the Royal Australian Navy's Type 12 Frigates, which were re-designated as River Class Destroyer Escorts. These were removed from service when the final ship of this class was decommissioned in the late 1990's. In their final variant, fire control was provided by a GWS-21 guidance system supported by a Mk 44 fire control computer. 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.
Seacat was widely used in NATO and Commonwealth navies that purchased British equipment. In addition to the U.K. and Australia, it was also used by Argentina, Brazil, Chile, Germany, Indonesia, India, Iran, Jordan, Libya, Malaysia, New Zealand, the Netherlands, Nigeria, the Philippines, Qatar, South Africa, Sweden, Thailand, Venezuela and Zimbabwe.