This was a beam-rider Surface-to-Air missile roughly equivalent to the USA's Terrier missile program. The Mark 1 version was expected to be able to engage a high-altitude bomber at 15 nautical miles, about 50% greater range than the contemporary Terrier. The Mark 2 version included provisions for better low-altitude performance and an anti-ship mode.

Sea Slug is unique in having its four booster rockets attached around its nose rather than its tail and is designed to be stowed horizontally rather than vertically.

These missiles were only used on the County Class destroyers, some of which were later sold to Chile and Pakistan.


Designation Sea Slug GWS-1
Ship Class Used On County Class
Date In Service Mark 1: 1961
Mark 2: 1965
Weight 1,980 lbs. (898 kg), 4,400 lbs. (1,996 kg) with boosters
Dimensions Mark 1: 16.1 x 236 in (41 x 600 cm)
Mark 2: 16.1 x 240 in (41 x 610 cm)
Span (both): 56.6 in (144 cm)
Payload Approximately 200 lbs. (91 kg)
Speed / Range Mach 1.8
Mark 1: 15 nm, Max altitude of 30,000 feet (9,100 m)
Mark 2: 35 nm, Max altitude of 65,000 feet (20,000 m)
Propulsion Sustainer rocket plus four strap-on boosters


Data from:

  • "Jane's Pocket Book 9: Naval Armament" edited by Denis Archer
  • "The Naval Institute Guide to World Naval Weapon Systems 1991/92" by Norman Friedman

Page History

18 November 2006 - Benchmark

30 December 2013 - Replaced photograph of Sea Slug