Close-in weapon system

Phalanx CIWS

A close-in weapon system (CIWS), often pronounced sea-whiz, is a naval shipboard point-defense weapon for detecting and destroying at short range incoming anti-ship missiles and enemy aircraft which have penetrated the outer defenses.

Nearly all classes of modern warship are equipped with some kind of CIWS device.

Gun systems

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

• AK-630
• DARDO
• Denel 35mm Dual Purpose Gun
• Goalkeeper CIWS
• Kashtan CIWS
• Meroka CIWS
• Myriad CIWS
• Oerlikon Millennium 35 mm Naval Revolver Gun System^[1][2]
• Phalanx CIWS
• Sea Zenith
• Type 730 CIWS

Limitations of gun systems

• 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. This makes the timeframe for interception 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, particularly as the interception distance is short. This is especially true if the gun fires kinetic-energy-only projectiles.
• Guns can only fire at one target at a time; switching targets may take up to one second for training the gun.
• A gun must predict the target's course and aim at the predicted position. Modern anti-ship missiles make intentional erratic moves before impact, reducing the probability of being hit by unguided projectiles.

Comparison with current CIWS

Comparison of some current CIWS

	AK-630[3]	Phalanx CIWS [4]	Goalkeeper CIWS
Weight	9,114 kg (20,090 lb)	6,200 kg (14,000 lb)	9,902 kg (21,830 lb)
Armament	30 mm (1.2 in) 6 barreled GSh-6-30 Gatling Gun	20 mm (0.79 in) 6 barreled M61A1 Vulcan Gatling Machine Gun	30 mm (1.2 in) 7 barreled GAU-8 Gatling Gun
Rate of Fire	5000 rounds per minute	4500 rounds per minute	4200 rounds per minute
Range	4,000 m (13,000 ft)	3,600 m (11,800 ft)	2,000 m (6,600 ft)
Ammunition storage	2000 rounds	1550 rounds	1190 rounds
Muzzle velocity	900 m (3,000 ft) per second	1,100 m (3,600 ft) per second	1,109 m (3,638 ft) per second
Elevation	-12 to +88 degrees	-25 to +85 degrees	-25 to +85 degrees
Traverse	360 degrees	-150 to +150 degrees	360 degrees

Missile systems

A Tor missile launch from the Russian Navy's Kirov class battlecruiser Frunze.

Missile systems do not have the same limitations of gun systems. 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 for a second mount for this role.

After an inertial guidance phase, a 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:

• 9K33 Osa (SA-N-4 Gecko) missile, used by the Russian Navy is stored and fired from TELARs(Transporter erector launcher and radar) on various Russian ships.
• 9K331 (SA-N-9 Gauntlet) missile, used by the Russian Navy, it is stored and fired from Vertical launching systems of various ships. It along with the Tor missile system is the first air-defense system designed from ground up to intercept precision guided munitions like the AGM-86 ALCM^[5]
• 9M311 (SA-N-11 Grisom) missile, used by the Russian and Chinese navies as part of the Kashtan gun-missile system.
• Barak SAM, an Israeli point defence missile system also used by Indian Navy.
• Crotale-NG
• HQ-7 missile, a Chinese missile system, standard for all ships.
• RIM-116 Rolling Airframe Missile - SeaRAM is a companion to the Phalanx, using Phalanx' sensor suite and an 11-missile RAM launcher
• 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, Turkish and Australian navies.

Land based CIWS

CIWS are also used in a land based anti-mortar and missile defense role to protect fixed and temporary bases and other facilities.^[6][7]

On a smaller scale, active protection systems are used in some tanks, and several are in development. The Drozd system was deployed on Soviet Naval Infantry tanks in the early 1980s, but later replaced by explosive reactive armour. Other systems are available or under development are the Russian (Arena), Israeli (Trophy), American (Quick Kill) and the South African-Swedish (LEDS-150).

See also

• Active protection system
• Metal Storm (company)
• Armour-piercing discarding sabot

References

1. ^ http://www.rheinmetall-defence.com/index.php?lang=3&fid=2177
2. ^ http://www.rheinmetall-detec.de/index.php?fid=1570&lang=3&pdb=1
3. ^ http://www.indian-military.org/navy/ordnance/close-in-weapon-system/267-ak-630-gatling-gun-close-in-weapon-system.html
4. ^ http://www.navy.mil/navydata/fact_display.asp?cid=2100&tid=800&ct=2
5. ^ "ЗЕНИТНЫЙ РАКЕТНЫЙ КОМПЛЕКС 9К330 "ТОР" (SA-15 Gauntlet)" (in Russian). Вестника ПВО. 2007-08-21. http://pvo.guns.ru/tor/tor.htm. Retrieved 2010-09-01. 
6. ^ http://www.usi-inc.net/23.html
7. ^ http://www.digital-battlespace.com/2009/05/bundeswehr-chooses-rheinmetall-nbs-c-ram-anti-mortar-rocket-artillery-system/

External links

• Spanish CIWS System Meroka
• CIWS action video