20 mm Phalanx Close-in Weapon System - CIWS

The following excerpt is from the Naval Weapons website . Used with permission from http://www.NavWeaps.com

Photo Courtesy of Dan L. Lamkin, Defense Systems Division Manager, NSWC PHD Det Louisville


The Phalanx is the most numerous close-in weapon system (CIWS) in the world and has been exported to many other countries. Phalanx provides ships with a terminal defense against anti-ship missiles that have penetrated other fleet defenses. While Phalanx is considered a completely “last ditch” weapon system, it has merits that many other CIWS systems do not. The Phalanx is very much a self contained system requiring minimal deck space and wiring.

CIWS are designed to engage anti-ship cruise missiles and fixed-wing aircraft at short range. Unlike many other systems, which have separate, independent systems, Phalanx combines search, detection, threat evaluation, acquisition, track, firing, target destruction, kill assessment and cease fire into a single mounting.

A prototype unit was installed for evaluation purposes on USS King (DLG-10) in 1973. In 1975 another prototype was mounted on the hulked USS Alfred A. Cunningham (DD-752) while several different kinds of missiles were fired against it. All of these missiles, including a Walleye, were destroyed before reaching the ship. A pre-production Phalanx unit underwent operational tests and evaluation onboard USS Bigelow (DD-942) in 1977. These tests showed that the unit exceeded the required maintenance and reliability specifications. The evaluations included tests with high levels of jamming noise during which the unit succeeded in distinguishing small missile-like targets against nearby islands.

Nomenclature Note: The Phalanx gun system itself is designated as the Mark 15. The CIWS mounting is designated as the Mark 72.
Prototype CIWS prepared to be loaded onto the USS KING (from the National Archives, College Park, MD) Prototype CIWS on the fantail of the USS KING (from the National Archives, College Park, MD)