Sea Dart

Sea Dart or GWS30^{[Note 1]} was a British surface-to-air missile system designed by Hawker Siddeley Dynamics and built by British Aerospace from 1977. It was fitted to the Type 42 destroyers (UK and Argentina), Type 82 destroyer and Invincible-class aircraft carriers of the Royal Navy. The missile system has had nine confirmed successful engagements in combat, including six aeroplanes, two helicopters and a missile.

History

Sea Dart began as Hawker Siddeley project "CF.299", a weapon to replace the Royal Navy's first-generation long-range surface-to-air missile, Seaslug. It entered service in 1973 on the sole Type 82 destroyer HMS Bristol before widespread deployment on the Type 42 destroyer commencing with HMS Sheffield in 1976. The missile system was also fitted to Invincible-class aircraft carriers but was removed during refits in the 1998-2000 period to increase the area of the flight deck and below-decks stowage associated with the operation of Royal Air Force Harrier GR9 aircraft.

Design

Sea Dart missile

Sea Dart is a two-stage, 4.4-metre (14 ft) long missile weighing 550 kilograms (1,210 lb). It is launched using a drop-off Chow solid-fuel booster that accelerates it to the supersonic speed necessary for the operation of the cruise motor, a Rolls-Royce [Bristol Siddeley] kerosene-fuelled Odin ramjet. This gives a cruise speed of over Mach 2.5, and unlike many rocket-powered designs the cruise engine burns for the entire flight, giving excellent terminal manoeuvrability at extreme range. It is capable of engaging targets out to at least 30 nautical miles (35 mi; 56 km) over a wide range of altitudes. It has a secondary capability against small surface vessels, tested against a Brave-class fast patrol boat, 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 46 litres (10 imp gal; 12 US gal) 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 (see below) able to engage more. Firing is from a twin-arm trainable launcher that is loaded automatically from below decks. The original launcher seen on the Bristol was significantly larger than that which appeared on the Type 42 and Invincible classes. Initial difficulties with launcher reliability have been resolved.

Combat Service

Falklands War

Sea Dart on Cardiff in 1982 (taken after the Falklands War had ended)

Sea Dart was used during the Falklands War (1982) and is credited with seven confirmed kills (plus one British Aérospatiale Gazelle helicopter downed by friendly fire). One kill was against a high-flying Learjet 35A reconnaissance aircraft beyond the missile's stated technical envelope on 7 June. In another engagement on 13 June, a high-flying Argentine B.Mk62 Canberra was shot down. Other kills were made against low-flying attack aircraft.

The net effect of Sea Dart was to deny the higher altitudes to enemy aircraft. This was important because Argentine aircraft such as the Mirage III had better straight line performance than the Sea Harriers, which were unlikely to successfully intercept them.

The first confirmed Sea Dart kill was an Aérospatiale Puma, on 9 May 1982 near Stanley by Coventry, with the loss of the 3 men aboard.

On 25 May 1982 an 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 iron bombs and sunk.

The same day a Super Étendard strike fighter sought to attack the British carrier group with Exocet missiles, but instead struck the cargo ship MV Atlantic Conveyor. Invincible fired 6 Sea Darts in less than 2 minutes, but all missed.

Canberra bomber B-108 of Grupo de Bombardeo 2. This Argentine aircraft was shot down by a Sea Dart on June 13

On 30 May 1982, during the last Exocet air attacks against the British fleet, the most successful engagements with Sea Dart occurred and Exeter was credited with two Skyhawks (out of four attackers) downed, despite them flying only 10–15 metres (33–49 ft) above the sea (theoretically below Sea Dart's minimum engagement altitude of 30 metres (98 ft)). One of the two was engaged by Type 21 frigate Avenger with her 4.5-inch (110 mm) gun^[1] On 6 June Exeter downed a Learjet 35A (destroying its tail) that was being used as reconnaissance aircraft, at 12,000 metres (39,000 ft) altitude, but missed a second one.

On 6 June 1982, Cardiff fired two Sea Dart missiles at an aircraft believed to be an Argentine C-130 Hercules. The missiles 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, a Canberra Mk.62 was flying at 12,000 metres (39,000 ft). While it was en route to bomb British troops at Port Harriet House, it was destroyed by a Sea Dart fired from Cardiff.^[2]

Sea Dart on Invincible

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 percent; however a number of missiles were fired without guidance to deter low level attacks. Exeter's 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.^[3][4] 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, causing the fuze to remain in safe mode and not function on impact.

Persian Gulf War (1991)

In February 1991 during the Persian Gulf War the US battleship Missouri, escorted by Gloucester (carrying Sea Dart) and USS Jarrett (equipped with Phalanx CIWS), was engaged by an Iraqi Silkworm missile (NATO reporting name "Seersucker"). The Silkworm missile was intercepted and destroyed by a Sea Dart fired from Gloucester. This was the first time any missile had successfully engaged another missile during combat at sea. During the same engagement, the Jarrett's Phalanx 20 mm CIWS was placed in autoengagement mode and targeted chaff launched by the Missouri rather than the incoming missile.^[5][6]

Variants

The Sea Dart was upgraded over the years - notably its electronics - as technology advanced. The following modification standards have been fielded:

• Mod 0 — Basic 1960s version, used in the Falklands. Vacuum-tube technology. Range circa 40 nmi (46 mi; 74 km).
• Mod 1 — Improved Sea Dart. Upgraded version 1983-1986. Updated guidance systems possibly allowing some capability against sea-skimming targets and much greater reliability.
• Mod 2 — 1989-1991. Upgrade included ADIMP (Air Defence IMProvement) which saw the replacement of six old circuit cards in the guidance system with one, allowing the spare volume to be used for an autopilot. Used alongside a command datalink (sited on the Type 909 pedestal) it allows several missiles to be 'in the air' at once, re-targeted during flight etc. and allows an initial ballistic trajectory, doubling range to 80 nmi (92 mi; 150 km) with the upgraded 909(I) radar for terminal illumination only.
• Mod 3 — Latest version with new infrared fuze. Delayed eight years from 1994 to 2002.

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.^[7]

Withdrawal

HMS Edinburgh conducting the final Sea Dart missile firing at the north western Scottish range of Benbecula. The ship fired five missiles, three single missiles and a two-missile salvo at an unmanned drone target.

The Sea Dart equipped Type 42s reached the end of their service lives, with all vessels already retired. They were replaced by the larger Type 45 which are armed with the Sea Viper missile system. Sea Viper is much more capable in the anti-air role but has no anti-surface capability. The first-of-class began sea trials in July 2007 and Daring entered service in 2009.^[8]

On 13 April 2012 HMS Edinburgh fired the last ever operational Sea Dart missiles after a thirty-year career. The last two remaining Type 42s, York and Edinburgh completed their careers without the system being operational.^[9]

A launcher with drill missiles has been preserved and is on display at Explosion! Museum of Naval Firepower, Gosport, Hampshire.

Operators

Map with former Sea Dart operators in red

Former operators

 Argentina

• Argentine Navy: Purchased 60 missiles for their two Type 42 destroyers but retired them in 1987 due to lack of spares.

 United Kingdom

• Royal Navy

References

Notes

Citations

Bibliography

See also