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Phalanx CIWS

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 defenses). Typically, the acronym is pronounced "Sea-whiz".

A CIWS usually consists of a combination of radars, computers, and multiple rapid-fire medium-calibre guns placed on a rotating gun mount. Examples of CIWS products in operation are

• German - Rheinmetall Millennium 35 mm Naval Revolver Gun System [1]
• United States Raytheon-designed Phalanx system
• Dutch-built Goalkeeper
• Turkish Sea Zenith
• Spanish Meroka CIWS
• Russian AK-630 or Kashtan
• Italian DARDO or Myriad
• Chinese Type 730
• Israeli Typhoon
• South African Denel 35DPG [2]

Nearly all classes of modern warship are equipped with some kind of CIWS device. Smaller CIWS-like defenses are currently being developed for main battle tanks in the USA, Israel, China and Russia ("Drozd" and "Arena" grenade launchers in the case of Russia, TROPHY in the case of Israel).

The current trend in CIWS is to use missile systems instead of guns, because guns have certain limitations:

• Short range: The maximum effective range of 30-mm gun systems is about 4500 m; systems with lighter projectiles have even shorter range. The expected real-world kill-distance of an incoming anti-ship missile is about 500 m or less,^{[citation needed]} still close enough to possibly cause damage on the ship's sensor or communication arrays. Also the timeframe for interception is relatively short; for supersonic missiles moving at 1500 m/s it is approximately one-third of a second.
• Limited kill probability: Even if the missile is hit and damaged, it may not be enough to destroy it or change its course enough, to prevent it or fragments of it from hitting its intended target (short interception distance, see above). This is especially true if the gun fires kinetic-energy-only projectiles (e.g., Phalanx with DU rounds).
• They are only able to engage one target at a time and switching targets needs up to one second for training the gun. A coordinated salvo of missiles can easily overwhelm a gun-based CIWS.
• For a gun hitting a target traveling at high speed, it has to predict its course and aim ahead of it since mid-course corrections of projectiles are not possible. Modern anti-ship missiles make erratic moves before impact, reducing the probability of being hit.

Because of their greater range, a missile-CIWS can also be dual-used as a short-ranged area-defense anti-air weapon, eliminating the need of a second mount for this role.

A RAM launcher of the German Navy

After an inertial guidance phase CIWS missile relies on infra-red, passive radar/ESM or semi-active radar terminal guidance or a combination of these. The ESM-mode is particularly useful since most long-range anti-ship missiles use radar to home in on their targets. Some systems allow the launch platform to send course-correction commands to the missile in the inertial guidance phase.

Examples include:

• Crotale-NG
• RAM - Sea-RAM is a direct replacement for Phalanx, using Phalanx' sensors and mounts
• Sadral, using a version of the Mistral missile
• Sea-Sprint, using the ADATS missile
• Modernized Sea Wolf
• Sea Sparrow Block 1, Missile used by the Nimitz class carriers, and other USN ships, as a short to medium range anti-aircraft weapon.
• Evolved Sea Sparrow missile, used aboard all Sea Sparrow-capable warships, plus other warships of the Netherlands, Canadian, Spanish, Japanese and Australian navies.
• SA-N-11 Grisom missile, used by the Russian and Chinese navies as part of the CADS-N-1 system.

• Point-defense
• Active protection system
• Metal Storm
• Armour-piercing discarding sabot

• Spanish CIWS System Meroka
• CIWS action video