page_title: Seaslug (missile)
section_title: Service performance
hierarchical_section_title: Seaslug (missile) / Service performance
caption_attribution_description: Seaslug GWS2 SAM launcher of &quot;County&quot; Class (Batch 2) Destroyer &quot;HMS Glamorgan&quot;, 6,200 tons, launched 1964, commissioned 1966 at Swansea Docks, c.1972. Scanned photograph taken with a Kowa SET.
context_page_description: Seaslug was a first-generation surface-to-air missile designed by Armstrong Whitworth for use by the Royal Navy. Tracing its history as far back as 1943's LOPGAP design, it came into operational service in 1961 and was still in use at the time of the Falklands War in 1982.
  Seaslug was intended to engage high-flying targets such as reconnaissance aircraft or bombers before they could launch stand-off weapons. It was only fitted to the Royal Navy's eight County-class destroyers which were designed around the missile system. Seaslug was only fired in anger once as an anti-aircraft missile, from HMS Antrim during the Falklands War, but missed its target. Later improvements meant that it could also be used against ships and ground targets.
  It was planned that Seaslug's medium-range role was to be supplanted by a very long-range missile known as Blue Envoy, but this was passed over in favour of a new medium-range system, Sea Dart. Sea Dart entered service in 1973 on the Type 82 destroyers and replaced Seaslug during the 1980s as the County-class destroyers were removed from service.
context_section_description: Seaslug was a high-performance weapon in the 1960s, with a single-shot kill probability of 92%, although other sources give lower kill probabilities: 75% for the Mk 1 and 65% for the Mk 2. The first four ships of the County-class (Batch 1) operated the Seaslug Mk 1, while the final four (Batch 2) were fitted with the ADAWS command and control system which enabled them to carry the more capable Mk 2 version. A proposal to refit the Batch 1 ships with ADAWS was dropped in 1968.
  During the Falklands War Seaslug was only launched once against an aircraft target, by HMS Antrim without success. On 21 May 1982 in Falkland Sound, the Antrim which had already had an unexploded 1,000 lb bomb pass through the Seaslug magazine, fired a single missile (some sources say two) at one of a second wave of attacking IAI Dagger fighters. It was unguided because the aircraft was too low to be acquired; the launch was intended to deter the pilot and to remove the exposed missile from the ship because it posed a fire hazard. The first combat use in the surface-to-surface role was during a shore bombardment on 26 May, when HMS Glamorgan fired Seaslugs at Port Stanley Airport claiming the destruction of a number of helicopters and a radar installation. A total of eight Seaslug Mk 2 missiles were launched in theatre by the two ships armed with them, including two missiles jettisoned by Glamorgan after she was hit by a land-launched Exocet missile on 12 June. Also during 1982, the Mk2 was used as a trials target for Seadart, but there were reliability problems with both systems. 
  The last firing of the Seaslug Mk 1 was in December 1981 by HMS London, the final GWS1 (or Batch 1) ship in active service. HMS Fife was converted to a training ship, and had her Seaslug systems removed, freeing up large spaces for classrooms and was completed in June 1986. Fife and the remaining GWS2 ships were sold to Chile between 1982 and 1987. Initially, the British government had hoped that the Chileans would accept a package to upgrade the ships to operate Seadart, but this was not taken up and they were transferred complete with Seaslug. The Chilean ships were later refitted with an extended flight deck in place of the Seaslug launcher.
caption: The Seaslug launcher mounted on the quarterdeck of HMS Glamorgan.
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