A Close-in weapon system (CIWS) is a naval shipboard weapon system for detecting and destroying incoming anti-ship missiles and enemy aircraft at short range (the threat(s) having penetrated the ship's available outer defences). Typically, the acronym is pronounced "See-whiz."

A CIWS usually consists of a combination of radars, computers, and multiple rapid-fire medium calibre guns placed on a rotating gun mount. One of the more well-known CIWS products in operation is the US Navy's Phalanx system. Another well-known CIWS is the Dutch-built Goalkeeper.

Nearly all classes of modern warship are equipped with some kind of CIWS system. Smaller CIWS-like defenses are currently being developed for MBTs (Main Battle Tanks) in China and Russia ("Drozt " and "Arena " grenade launchers in the case of Russia).

The concept of a CIWS came in the Indo-Pakistani War of 1971 when an Indian anti-ship missile penetrated the tanker PNS Dacca 's outer defences. Despite this, Leading Seaman Muhammed Hanif, manning his anti-aircraft gun, kept firing at the incoming missile till the last. Though he destroyed the missile and managed to save the ship, he was himself killed by the explosion. Muhammad Hanif left a legacy that gave birth to a new concept in naval warfare, the Close-in Weapon System, for defence against low flying anti-ship missiles.

CIWS trivia

• Because of the inefficiency and balkiness of the original CIWS units, the acronym received the facetious expansion of "Christ! It won't shoot!"

See also

• Metal Storm