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Sea Dart, or GWS.30 was a Royal Navy surface-to-air missile system designed in the 1960s and entering service in 1973. It was fitted to the Type 42 , the single Type 82 destroyer and the s. Originally developed by Hawker Siddeley, the missile was built by British Aerospace after 1977. It was withdrawn from service in 2012.
Britain's first naval surface-to-air missile was GWS1 Seaslug, which entered service in 1963. This used beam riding guidance which offered limited accuracy and was useful only against slower targets. The need for a higher performance system was seen even as it entered service.
Bristol Aerospace, which had recently introduced the ramjet-powered Bloodhound missile for the RAF, offered a new ramjet powered concept, while British Aircraft Corporation (BAC) proposed a shorter-range rocket powered design. The Admiralty asked for a proposal combining BAC's layout with Bristol's engine, which became Sea Dart. Compared to Seaslug, Sea Dart was faster, had much greater range, and its semi-active radar homing guidance was much more accurate and allowed attacks against supersonic targets. After the Falklands War, further updates dramatically increased its range, reaching .
The system had nine confirmed successful engagements in combat, including six aircraft, a helicopter and an anti-ship missile. This was the first time a missile had shot down another in combat. An additional helicopter was shot down in a 'friendly fire' incident during the Falklands.
Early experiments during the 1950s led to the development of the Seaslug system. Seaslug was useful against first-generation strike aircraft but had limited performance against faster aircraft or anti-ship missiles. Seaslug was also too large to be carried by a frigate-sized ship, leaving smaller ships with little air defence. Some consideration was given to a high-performance gun system for these ships, the DACR (direct-action, close-range), but calculations showed it would be useless against future anti-ship missiles that would manoeuvre on the approach.
Two systems were initially considered for the role. Bristol's RP.25 was a ramjet powered design with a long ogive wing that was boosted to speed by two detachable booster rockets under the missile in a layout not that different from Bristol's Bloodhound missile. The second was two-stage solid-fuel rocket known as SIG-15 from BAC, developed partially from BAC's work on the PT.428 which would later emerge as Rapier.
The Admiralty considered the range of the BAC entry, about , to be too short to be useful. The Bristol concept offered a much more useful maximum around . However, it also felt the BAC team, known as Project 502, was better able to manage the project. The Admiralty also demanded that the design be able to be moved about the ship in a fashion similar to gun ammunition, which made the winged RP.25 unsuitable. The result was a redesign effort with BAC designing the airframe and Bristol providing the engine.
A 1966 report estimated that CF.299 would have a two-shot kill probability (Pk) against an AS-2 Kipper missile of 0.8–0.9, whereas Seaslug II would manage only 0.35–0.55. Against a supersonic "Blinder" bomber, Pk was 0.5–0.8, compared to 0.3–0.5 for Seaslug. Additionally, because it flew faster than Seaslug, the total engagement time was shorter, and this meant the battery could salvo more rapidly. Finally, its ability to lead the target, compared to Seaslug's beam riding pursuit course, allowed it to attack targets with much higher crossing speeds. A 1968 study suggested Sea Dart would have the same capability as eight F-4 Phantoms on patrol.
By this time, many European navies had chosen the US RIM-24 Tartar surface-to-air missiles, but the Dutch Navy was interested in the British missile for a new class of advanced anti-air ships they were designing. The design mounted an advanced radar system, and an agreement was arranged where the Dutch would use the British missile and the RN ships would use the Dutch radar under the name Type 988 "Broomstick". This was a 3D radar with multiple antennas that provided both fast continual scanning as well as multiple independent targeting radars. Both the radar and missiles would be controlled by a new combat direction system being developed by both navies.
Ultimately, the Dutch also chose Tartar for their missile component, leaving the Royal Navy as the Sea Dart's only initial user. The Navy dropped its interest in Broomstick and continued development using simpler radars like the Type 965 radar that was already in service. This had the disadvantage of not being able to pick out targets against a background landform or high waves, significantly limiting its capabilities against low-flying strike aircraft.
In 1982, British Aerospace won a £100m contract to sell the Sea Dart system to China, but this fell through in 1983, with Chinese minister Chen Muhua explaining that China was "not satisfied with the price, technology or production".
Hawker Siddeley Dynamics, which had taken over Bristol, proposed using the Sea Dart missile as a replacement for both the British Army's Thunderbird and the RAF's Bloodhound. This Land Dart was launched from a four-round box that would be highly mobile. Hawker Siddeley Dynamics suggested that if the missile was used by all three British services, it would result in further sales as a NATO-standard SAM. The introduction of the VR.725 Thunderbird II led the Army to drop any interest in Land Dart, and the NATO contract eventually went to the MIM-23 Hawk.
Hawker Siddeley tried again in the 1970s when the Air Staff released GAST.1210, calling for a long-range missile to replace Bloodhound. It proposed a further updated Land Dart combined with a dramatically improved radar system, the Plessey GF75 Panther, a land-based version of the naval AWS-5. This concept ultimately went nowhere and the Bloodhound was removed from service in 1991 with no replacement. In the early 1980s, British Aerospace (BAe), who had taken over Hawker, re-launched the GAST.1210 concept under the new name Guardian. This proposed a lightweight two-round launcher and mobile version of Panther to be used as both a SAM and an anti-missile for short-range ballistic missiles like SCUD. Despite interest from the Middle East, no sales followed. The same launcher was also offered as Lightweight Sea Dart, which used its disposable shipping container as the launch tube, which was fit into a four-place trainable launcher that could also mount Sea Eagle. Most of the weight savings was in the launcher itself, allowing it to be fit to smaller ships.
The first upgrade was to replace the older Type 965 radar with the much better Type 1022. The Navy had originally planned on replacing the 965 with a new radar, then known as STIR, when it became available. As it became clear that STIR would not be available for some time, Marconi offered an interim model, the 1022. This had a new antenna design that greatly reduced the beamwidth from around 12 degrees to 2.3, and used a shaped broadcast pattern that greatly reduced the amount of signal that was aimed at waves and thereby reduced clutter.
The 1022 arrived in time to equip the "Batch II" Sheffields, which began in 1978 with HMS Exeter. Initially they had planned to re-equip the earlier ships as well, but as the new ships started arriving all desire to spend the money on the upgrades disappeared. As many of the problems with the Sea Dart could be traced to the failure of the 965 to provide any early warning against low-level engagements, the ability to offer dramatically improved performance with a relatively simple update that had been planned all along was suddenly considered very important.
It is capable of engaging targets out to at least over a wide range of altitudes. It has a secondary capability against small surface vessels, tested against a , although in surface mode the warhead safety arming unit does not arm, and thus damage inflicted is restricted to the physical impact of the half-ton missile body and the unspent proportion of the of kerosene fuel.
Guidance is by proportional navigation and a semi-active radar homing system using the nose intake cone and four aerials around the intake as an interferometer aerial, with targets being identified by a Type 1022 surveillance radar (originally radar Type 965) and illuminated by one of a pair of radar Type 909. This allows two targets to be engaged simultaneously in initial versions, with later variants able to engage more. Firing is from a twin-arm trainable launcher that is loaded automatically from below decks. The original launcher seen on HMS Bristol was significantly larger than that which appeared on Type 42 and Invincible classes. Initial difficulties with launcher reliability were resolved.
The net effect of Sea Dart was to deny the higher altitudes to enemy aircraft. This was important because Argentine aircraft such as the Dassault Mirage III had better straight line performance than the British Aerospace Sea Harriers, which were unlikely to successfully intercept them.
The first Sea Dart engagement was against an Aérospatiale Puma, on 9 May 1982 near Stanley by , with the loss of the three men aboard.
On 25 May 1982 an Douglas A-4C Skyhawk of Grupo 5 was shot down north of Pebble Island, again by Coventry. The pilot, Capitán Hugo Angel del Valle Palaver, was killed. Later, Coventry shot down another Skyhawk of Grupo 4 while it was returning from a mission to San Carlos Water. Capitán Jorge Osvaldo García successfully ejected but was not recovered. The next Argentine action that day sank Coventry. An unguided Sea Dart was launched in an effort to disrupt the attack but missed, and the destroyer was struck by two Unguided bomb and sank.
The same day a Dassault-Breguet Super Étendard strike fighter sought to attack the British carrier group with Exocet missiles, but instead struck the cargo ship . fired six Sea Darts in less than two minutes, but all missed.
On 30 May 1982, during the last Exocet air attacks against the British fleet, shot down two Skyhawks (out of four), despite their flying only above the sea (below Sea Dart's theoretical minimum engagement altitude of ). On 6 June Exeter shot down a Learjet 35A being used for reconnaissance at .
On 6 June 1982, Cardiff fired a Sea Dart missile at an aircraft believed to be an Argentine C-130 Hercules. The missile destroyed the aircraft, which was in fact a British Army helicopter. All four occupants were killed in this "friendly-fire" incident.
Finally, on 13 June 1982, an English Electric Canberra flying at en route to bomb British troops near Port Harriet House was destroyed by a Sea Dart fired from Cardiff.
In total at least eighteen missiles were launched by Type 42 destroyers, six by Invincible, and two by Bristol. Out of five missiles fired against helicopters or high flying aircraft, four were successful, but only two of nineteen fired at low level aircraft hit: just eleven per cent; however a number of missiles were fired without guidance to deter low level attacks. Exeters success can be partially attributed to being equipped with the Type 1022 radar, which was designed for the system and provided greater capability than the old Type 965 fitted to the earlier Type 42s. The Type 965 was unable to cope with low level targets as it suffered multiple path crossings and targets became lost in radar clutter from the surface of the South Atlantic. This resulted in Sea Dart being unable to lock onto targets at distance obscured by land, or fast-moving low-level targets obscured in ground clutter or sea-returns.
The Argentine Navy was well aware of the Sea Dart's capabilities and limitations, having two Type 42s of its own. Consequently, Argentine planes, opting to fly below the Type 965 radar ("sea skimming"), frequently dropped bombs which failed to explode. The arming vane on the bomb had insufficient time to complete the number of revolutions required to arm the fuze.
The Sea Dart Mark 2, GWS 31, (also known as Sea Dart II - not to be confused with Mod 2, above) development was cancelled in 1981. This was intended to allow 'off the rail' manoeuvres with additional controls added to the booster. The Mark 2 was reduced to Advanced Sea Dart, then Enhanced Sea Dart and finally Improved Sea Dart.
Lightweight Sea Dart was a version with minimal changes to the missile itself, but based in a new sealed box-launcher. A four-box trainable launcher was developed that allowed it to be mounted to ships as small as 300 tons displacement. The same box and launcher could also support the Sea Eagle SL, the proposed ship-launched version of Sea Eagle. Guardian was a proposed land-based system of radars, control stations and the Lightweight Sea Dart proposed in the 1980s for use as a land-based air defence system for the Falkland Islands. Neither system was put into production.
On 13 April 2012 fired the last operational Sea Dart missiles. The last two remaining Type 42s, and Edinburgh completed their careers without the system being operational.
A launcher with drill missiles has been preserved and is on display at Explosion! Museum of Naval Firepower, Gosport, Hampshire.
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