Sea Dart or Guided Weapon System (GWS) 30 is a British surface-to-air missile system designed by Hawker Siddeley Dynamics and built by British Aerospace (BAe) from 1977.

It was fitted to the Type 42 (UK and Argentina) and Type 82 guided missile air defence destroyers and Invincible class light aircraft carriers of the Royal Navy.

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, Sea Slug. It entered service in 1973 on the sole Type 82 destroyer HMS Bristol before widespread deployment on the Type 42 destroyer. The missile system was also fitted to Invincible class aircraft carrier 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 is a two-stage, 4.4 m long missile weighing 550 kg. It is launched using a drop-off Chow solid-fuelled booster that accelerates it to the supersonic speed necessary for the operation of the cruise motor, a Rolls-Royce (Bristol Aerojet) 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 over a wide range of altitudes. It has a secondary capability against small surface vessels, tested against a 'Brave' class fast patrol boat, although the warhead is too small to inflict major damage on larger vessels.

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 1 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 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 reconnaissance aircraft beyond the missile's stated technical envelope. In another engagement, a high-flying Argentinian Canberra bomber 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 Argentinian aircraft such as the Mirage had better performance than the Sea Harriers, which were unlikely to successfully intercept them. The Argentine losses officially recorded were two A-4 Skyhawks, one Aérospatiale Puma, one English Electric Canberra and one Learjet. Another two A-4 Skyhawks were possibly destroyed.

The two possibles were engaged on the 9th of May 1982 when HMS Coventry became the first Royal Navy warship to fire the Sea Dart SAM (Surface-to-Air Missiles) in anger when the ship fired three on 9 May destroying two A-4 Skyhawks of FAA Grupo 4, with one aircraft found on South Jason Island. Lt Casco and Lt Farias were both killed. The third was fired at a Hercules on a supply run but it escaped unharmed as the Sea Dart was fired at maximum range.

Some reports suggest that these two Skyhawks were lost in bad weather, however Coventry did fire at distant contacts at the same time Lt Casco and Lt Farias were lost and the targets disappeared from radar, but hits could not be confirmed. HMS Broadsword reported that their radar had tracked the missile merging with the pair of Skyhawks. They may well have both been downed by Coventry’s missiles, or collided while attempting to evade it.

The first Authenticated claim was the Puma, on May 9 1982 near Stanley by HMS Coventry and shot down by a single missile, with the loss of 3 men aboard. Three days later, HMS Glasgow was patrolling near Port Stanley with the frigate HMS Brilliant when four A-4s attacked at low level. All but one were shot down by Brilliant's short range Sea Wolf missiles. This was followed by a second wave of four machines and neither Sea Dart nor Sea Wolf functioned to contest these incoming aircraft. Glasgow had a lucky escape when a bomb passed through her flank into the sea without exploding.

The next action saw the sinking of Coventry, on 25 May 1982, and again no Sea Dart was able to engage the A-4s, although one was launched "blind" (without radar control) in an effort to disrupt the enemy attack. HMS Broadsword was unable to engage the aircraft as Coventry had cut across her while making evasive manoeuvres and broken her lock on the target. This time the destroyer was struck by three bombs and sunk. That same day a Super Etendard strike fighter sought to attack the British carrier group with Exocet missiles, but instead struck the cargo ship MV Atlantic Conveyor. Invincible fired six missiles in less than two minutes, but all missed.

On May 30, during the last of the air attacks against the British fleet, the most successful engagements with Sea Dart occurred and Exeter was credited with two A-4s (out of four attackers) downed, despite them flying only 10-15 meters above the sea (theoretically below Sea Dart's minimum engagement altitude of 30 m). One of the two was engaged by a Type 21 frigate with her 4.5 inch gun On June 6 Exeter downed a Learjet 35A that was being used as reconnaissance aircraft, at 12,000 m (12 km) altitude, but missed a second one. Finally, a Canberra was hit on 13 June, again flying at 12,000 m.

In total at least eighteen missiles were launched by Type 42 destroyers, and six by Invincible. 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 . 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 Argentinian Navy was well aware of the Sea Dart's capabilities and limitations, having two Type 42s of its own. Consequently, Argentinian 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, in which case, the fuze remained in safe mode and would not function on impact.

Gulf War (1991)

In February 1991 during the Gulf War the battleship USS Missouri, escorted by HMS Gloucester (carrying Sea Dart) and the USS Jarrett (equipped with Phalanx CIWS), was engaged by an Iraqi Silkworm missile (also known as a Seersucker). The Silkworm missile was intercepted and destroyed by a Sea Dart fired from Gloucester. During the same engagement, the Jarrett Phalanx 20 mm CIWS was placed in autoengagement mode and targeted chaff launched by the Missouri rather than the incoming missile. This engagement was the first validated, successful engagement of a missile by a missile during combat at sea, though the engagement was tail-end after the Silkworm had flown past the Gloucester.

Variants

The Sea Dart has been upgraded over the years - notably its electronics - as technology advances. The following Modification standards have been fielded:

• Mod 0 — Basic 1960s version, used in the Falklands. Vacuum-tube technology. Range circa 40 nm.
• 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 nm 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, (a.k.a. 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.

Guardian was a proposed land-based system of radars, control stations and a box-launched version of Sea Dart proposed in the 1980s for use as a land-based air defence system for the Falkland Islands. A similar lightweight box-launched version was also proposed for small naval craft.

Withdrawal

The Sea Dart equipped Type 42s are reaching the end of their service lives, with some vessels already retired. They will be replaced by the larger Type 45 class which is armed with the much more capable PAAMS missile system. The first of class began sea trials in July 2007 and will enter service in 2009.

Operators

• Argentine Navy
• Royal Navy

References

• Britain's Modern Royal Navy, Paul Beaver, Patrick Stephens Limited, 1996 ISBN 1-85260-442-5
• Naval Armament, Doug Richardson, Jane's Publishing, 1981, ISBN 0-531-03738-X
• War Machines enciclopedy, Limited publishing, 1984 page 866 (Italian version printed by De Agostini) and page 1260-1268
• Enciclopedy War Machines, 1265-70 and 864-65 (Italian edition)

See also