Phalanx CIWS
The Phalanx CIWS (Close-in weapon system, pronounced see-whizz) is an anti-missile system designed and manufactured by Raytheon Company. It is used by the United States Navy and on the vessels of over twenty international allied navies.
It was developed as the final line of defense (terminal defense) against anti-ship missiles (AShMs), including terminal-maneuvering sea-skimmers. The first system was offered to the US Navy for evaluation on the USS Bigelow in 1977. It was accepted and production started in 1978, the first ship fully fitted out was the USS Coral Sea in 1980.
The basis of the system is a 20mm M61 Vulcan firing at over 4,500 rounds per minute (early models only fired 3,000 rounds per minute). The gun is mounted in a self-contained turret along with a automated fire control system. The system automatically searches, detects, tracks, engages and confirms kills using its computer-controlled radar system. The entire unit weighs 5625 kg or 6120 kg.
The Navy has unofficially nicknamed the Phalanx CIWS R2-D2 after the prominent radar dome on top. It is the only deployed system which will automatically detect and engage targets with no human intervention.
CIWS has been developed through a number of different configurations. The basic style is the Block 0. The Block 1 (1988) offers various improvements in radar, ammunition, rate of fire and computing. Block 1A introduced a new computer system. The Block 1B PSuM (Phalanx Surface Mode, 1999) adds a forward looking infrared (FLIR) sensor to allow the weapon to be used against surface targets. This addition was developed to provide ship defense against small vessel threats and other "floaters" in littoral waters and to improve the weapon's performance against slower low-flying aircraft. The Block 1B also allows for human intervention to identify and target threats.
The US Navy uses armor-piercing penetrator rounds, originally depleted uranium but now tungsten. All Phalanx systems hold 1500 rounds in their magazines.
The US Navy is in the process of upgrading all their Phalanx systems to the Block 1B configuration. The Block 1B is also used by international navies such as Japan, Egypt and Bahrain. Canada is currently upgrading its entire Phalanx inventory to Block 1B.
