The General Dynamics Corporation 20-mm Phalanx Mk 15/16 CIWS is a total weapons system which automatically carries out search and detection, target threat evaluation, tracking and firing against high-performance antiship missiles and aircraft as a 'lastditch' defence. The Phalanx is built around the General Electric 20-mm M61A1 six-barrel 'Gatling' gun, and is hydraulically powered. Production started in late 19~7, the first operational units being installed aboard the aircraft-carriers USS Enterprise and America during 1980. Current plans are for the US Navy to fit some 400 or more mounts in more than 250 ships, with frigates having only a single system and the 'Iowa' class battleships four. In order to enhance the Phalanx's capabilities a product-improvement programme is under way to increase the search-area and target-detection performance, and to provide for greater flexibility. By the end of 1984 220 Phalanxes had been installed aboard 125 US Navy ships, while a further 52 had been supplied to foreign buyers. Amongst the navies known to have Phalanx either in service or on order are those of Australia, Canada, Israel, Japan, Saudi Arabia and the UK. In the case of the last the systems were apparently ordered before the Falklands war for the 'Invincible' class carriers, with the first delivery being

accelerated to equip HMS Illustrious.The Invincible and Illustrious did carry two, while the  Ark Royal had three, but have been upgraded to 30mm Goal Keeper CIWS. In live firing trials undertaken by the US Navy and the Royal Navy the Phalanx has proved capable of detecting and destroying MM.38 Exocet anti-ship missiles that may threaten Royal Navy ships in any future conflict in the South Atlantic.

Specification Phalanx Mk 15/ 16 Calibre: 20 mm Number of barrels: six Elevation: -25° to +80°

Muzzle velocity: 1097 m (3, 600 ft) per second

Effective range: 500-1500 m (545-1, 640 yards)

Rate of fire: 3, 000 rounds per minute Weight: (with ammunition) 6092 kg (13,430 lb)

Number of rounds on mount: 1, 000 (latest Block 1 version is believed to have 1,400-1,600)