Sea Skua

Sea Skua missile on display

Sea Skua ultimately traces its history to the immediate post-war era. Growing increasingly concerned about the threat of aircraft, especially after the introduction of glide bombs during the war, the Royal Navy had long been convinced that all ships required some form of surface-to-air missile (SAM) for defence. These systems tended to be relatively large, especially in the era before vertical launch, and it was difficult to mount both a useful SAM and a conventional gun on smaller ships. A gun was considered vital as the Navy's mission changed from one focused entirely on combat with the Soviet Union to the projection of power worldwide.

This led to a series of experiments to produce a dual-use missile capable of both anti-air and anti-ship use. The original Navy guided missile sets, Seaslug and Seacat, both had secondary anti-shipping roles. Seaslug was a large system and could only be carried by larger ships, while Seacat could be fit to almost any ship but had a relatively short range and small warhead. Neither filled the goal of replacing guns. In October 1960 the Navy launched a project with the goal of producing a single weapon that could fit on a 3,000 ton frigate and able to attack bombers, anti-shipping missiles, and other ships up to frigate size. This led to the Small-Ship Guided Weapon and ultimately to Sea Dart. This system also proved too large for the smallest ships and the need remained unfilled.

The sinking of the Eliat in 1967 led to the realization that small fast-attack boats were a serious immediate threat. A weapon was needed that could destroy any such craft before it could approach within the launching range of its missiles. Seacat did not have anywhere near the required range. Sea Dart did have the needed range, but could not be fit to the majority of RN ships. A new conventional missile might be dedicated to the role, but it would have to be roughly the same size as those being aimed against it in order to reach the required range, which would make it take up too much room on a ship carrying many other weapons systems.

Giving up on the original idea of having a dual-purpose weapon, the entire concept was reevaluated and led to the decision to launch the weapon from helicopters. This would allow a small weapon to have both the required range and warhead size. The missile would be carried by the new Westland Lynx and its targets detected by their Seaspray radar. Long range was not required, it only needed to be enough to keep the helicopter out of range of any anti-aircraft weapons the boats might carry. Because the boats were small, these would be light weapons with limited range. Its combat effectiveness was further improved by the addition of the Racal "Orange Crop" ECM suite, which allowed the helicopter to track the boats who were using radar to attempt to approach their target ships, allowing the helicopters to approach without turning on their Seaspray until the last moment.

The British Aircraft Corporation (BAC) began development in May 1972. The British Government authorised its production in October 1975. At the time, the missile was known as CL.834.[1] The first launches took place in November 1979 at the Aberporth Range in Cardigan Bay. Three missiles were launched from the ground and three by helicopters. Further tests were made and in July 1981, full-scale production was ordered of the new missile, now called "Sea Skua".[2]

Sea Skua missile

With the missile weighing only 320 pounds (150 kg) at launch, a Lynx helicopter can carry up to four, two on each wing pylon. The booster is a Royal Ordnance (now Roxel UK) "Redstart" steel body, while the sustainer is a Royal Ordnance "Matapan" light alloy body. The missile flies at high subsonic speed to a range of up to 15.5 miles (24.9 km). The official range is declared to be 15 km, but this is widely exceeded. The missile has two sensors: a semi-active radar homing system by Marconi Defence Systems, and a Thomson-TRT AHV-7 radar altimeter (which is also used by the Exocet missile), built under licence by British Aerospace Defence Systems.[2]

The missile is launched into a cruise at a pre-selected altitude, with four settings for different surface conditions. The launching helicopter illuminates the target with its radar, normally the specially developed Ferranti Seaspray. As it approaches the pre-programmed location of the target, the missile climbs to a higher altitude in order to acquire the radar signal for final homing. Thia allows it to fly below the horizon for much of the journey, reducing the chance it will be noticed and allow the target to attempt to escape. On impact it penetrates the hull of a ship before detonating the 62 pounds (28 kg) blast fragmentation warhead. A semi armour piercing (SAP) warhead is also available; this contains 9 kilograms (20 lb) of RDX, aluminium and wax. The fuze is an impact-delayed model.[2]

The illuminating radar aboard Lynx helicopters is the GEC-Ferranti Seaspray I band, which weighs 64 kilograms (141 lb), a power of 90 kW, two modes (three in the improved model) and a 90° observation field. The Seaspray Mk. 3 had a rotating antenna with a 360° field of view. It is capable of operating in a track while scan (TWS) mode. The missile flight ends after 75–125 seconds, during which time the helicopter can manoeuvre at up to 80° from the missile path.[2]

Four Sea Skua canisters can be seen on the stern of Kuwaiti FAC Al Fahaheel (P3721) in May 2013

In addition to serving with the United Kingdom, the Sea Skua has been exported to Germany (where it will be replaced from 2012 onwards), India, Kuwait, and Turkey. It was generally preferred to the similar rival, the French-built AS 15 TT, even though the two missiles had similar performance. The guidance of AS-15TT was radio-command, and it required the Agrion 15 radar, unlike the more flexible British missile. Sea Skua's success in active service and its adoption by the Royal Navy resulted in considerable success in the international market.[3]

Royal Malaysian Navy service

An inert Sea Skua on the deck of a Kuwaiti ship

The Sea Skua entered service with the Royal Malaysian Navy as part of the package for the purchase of six AgustaWestland Sea Lynx 300 helicopters. The missiles supposedly cost RM104 million.

On 16 March 2006 the Royal Malaysian Navy test fired the Sea Skua missile as part of a contractual Firing exercise. The missile was fired eight miles down range from the 40m Surface Target Barge. The Sea Skua failed to hit its target and failed to explode. The fault was believed to have been traced to a faulty connecting pin wire that ignites the rocket motor. The missile fell into the sea, and was not recovered. The Royal Malaysian Navy ordered Matra Bae Dynamics (MBDA) to take back the missiles to conduct system checks, and re-tested.

On 12 February 2008, the Royal Malaysian Navy successfully conducted a second firing. The missile was fired from maximum range and hit a surface target.

Sea Skua is planned to be replaced in UK service by the Sea Venom.[6] The Royal Navy conducted its final Sea Skua live firing in March 2017.[7]

• Penguin (missile)
• Skua - the bird the missile is named after
• AS 15 TT
• Exocet

Wikimedia Commons has media related to Sea Skua.

• Video of a Malaysian Sea Skua live firing test