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Phalanx CIWS
Phalanx CIWS
Phalanx CIWS
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The Phalanx CIWS (SEE-wiz) is an automated gun-based close-in weapon system to defend military watercraft automatically against incoming threats such as aircraft, missiles, and small boats. It was designed and manufactured by the General Dynamics Corporation, Pomona Division,[3] later a part of Raytheon. Consisting of a radar-guided 20 mm (0.8 in) Vulcan cannon mounted on a swiveling base, the Phalanx has been used by the United States Navy and the naval forces of 15 other countries. The U.S. Navy deploys it on every class of surface combat ship, except the Zumwalt-class destroyer and San Antonio-class amphibious transport dock.[5] Other users include the British Royal Navy, the Royal Australian Navy, the Royal New Zealand Navy, the Royal Canadian Navy, and the U.S. Coast Guard.

Key Information

A land variant, the LPWS (Land Phalanx Weapon System), part of the Counter Rocket, Artillery, and Mortar (C-RAM) system, was developed.[6] It was deployed to counter rocket, artillery and mortar attacks during the 2021 US withdrawal from Afghanistan.[7][8] The U.S. Navy also fields the SeaRAM system, which pairs the RIM-116 Rolling Airframe Missile with sensors based on the Phalanx.

History

[edit]

The Phalanx Close-In Weapon System (CIWS) was developed as the last line of automated weapons defense (terminal defense or point defense) against all incoming threats, including antiship missiles (AShMs or ASMs), aircraft including high-g and maneuvering sea-skimmers, and small boats.

The first prototype system was offered to the U.S. Navy for evaluation on the destroyer leader USS King in 1973 and it was determined that further work was required to improve performance and reliability. Subsequently, the Phalanx Operational Suitability Model successfully completed its Operational Test and Evaluation (OT&E) on board the destroyer USS Bigelow in 1977.[2] The model exceeded operational maintenance, reliability, and availability specifications. Another evaluation successfully followed, and the weapon system was approved for production in 1978. Phalanx production started with orders for 23 USN and 14 foreign military systems. The first ship fully fitted out was the aircraft carrier USS Coral Sea in 1980. The Navy began placing CIWS systems on non-combatant vessels in 1984.

Design

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Phalanx prototype on the fantail of USS King in 1973
The ex-USNS Saturn during a sinking exercise, hit by rounds fired from the Mk-15 Phalanx CIWS onboard USS Mitscher
A technician checks the radar transmitter and microwave assemblies of a Phalanx CIWS; also visible (top left) is the search radar, with vertical tracking radar below it

The basis of the system is the 20 mm M61 Vulcan rotary cannon, used by the United States military on various tactical aircraft since 1959, linked to a Ku band fire control radar system for acquiring and tracking targets. This proven system was combined with a purpose-made mounting, capable of fast elevation and traverse speeds, to track incoming targets. An entirely self-contained unit, the mounting houses the gun, an automated fire-control system and all other major components, enabling it to automatically search for, detect, track, engage, and confirm kills using its computer-controlled radar system. Owing to this self-contained nature, Phalanx is ideal for support ships, which lack integrated targeting systems and generally have limited sensors. The entire unit has a mass between 12,400 to 13,500 lb (5,600 to 6,100 kg).[citation needed]

Because of their distinctive barrel-shaped radome and their automated operation, Phalanx CIWS units are sometimes nicknamed "R2-D2" after the droid from the Star Wars films.[9][10]

Upgrades

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The Phalanx system has been developed through several configurations. The basic (original) is the Block 0, equipped with first-generation, solid-state electronics and with marginal capability against surface targets. The Block 1 (1988) upgrade improved radar, ammunition, computing power, rate of fire, and an increase in maximum engagement elevation to +70 degrees. These improvements were intended to increase the system's capability against emerging Russian supersonic anti-ship missiles. Block 1A introduced a new computer system to counter more maneuverable targets. The Block 1B PSuM (Phalanx Surface Mode, 1999) adds a forward-looking infrared (FLIR) sensor to make the weapon effective against surface targets.[11] 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 FLIR's capability is also of use against low-observability missiles and can be linked with the RIM-116 Rolling Airframe Missile (RAM) system to increase RAM engagement range and accuracy. The Block 1B also allows for an operator to visually identify and target threats.[11]

Since the end of FY 2015, the US Navy has upgraded all Phalanx systems to the Block 1B variant. In addition to the FLIR sensor, the Block 1B incorporates an automatic acquisition video tracker, optimized gun barrels (OGB), and Enhanced Lethality Cartridges (ELC) for additional capabilities against asymmetric threats such as small maneuvering surface craft, slow-flying fixed and rotary-winged aircraft, and unmanned aerial vehicles. The FLIR sensor improves performance against anti-ship cruise missiles, while the OGB and ELC provide tighter dispersion and increased "first-hit" range; the Mk 244 ELC is specifically designed to penetrate anti-ship missiles with a 48 percent heavier tungsten penetrator round and an aluminum nose piece. Another system upgrade is the Phalanx 1B Baseline 2 radar to improve detection performance, increase reliability, and reduce maintenance. It also has a surface mode to track, detect, and destroy threats closer to the water's surface, increasing the ability to defend against fast-attack boats and low-flying missiles. As of 2019, the Baseline 2 radar upgrade has been installed on all U.S. Navy Phalanx system-equipped vessels.[12] The Block 1B is also used by other navies, such as Canada, Portugal, Japan, Egypt, Bahrain, and the UK.[13]

US Navy Phalanx CIWS maintenance and live firing test

In April 2017, Raytheon tested a new electric gun for the Phalanx allowing the system to fire at varying rates to conserve ammunition. The new design replaces the pneumatic motor, compressor, and storage tanks, reducing system weight by 180 lb (82 kg) while increasing reliability and reducing operating costs.[14]

Operation

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The CIWS is designed to be the last line of defense against anti-ship missiles. Due to its design criteria, its effective range is very short relative to the range of modern ASMs, from 1 to 5 nautical miles (2 to 9 km). The gun mount moves at a very high speed and with great precision. The system takes minimal inputs from the ship, making it capable of functioning despite potential damage to the ship.

The only inputs required for operation are 440 V AC three-phase electric power at 60 Hz and water (for electronics cooling). For full operation, including some nonessential functions, it also has inputs for ship's true compass heading and 115 V AC for the WinPASS subsystem. WinPASS (Windows-based Parameter Analysis and Storage Subsystem) is a secondary computer built into the local control station that allows technicians to perform various tests on system hardware and software for maintenance and troubleshooting purposes. It also stores data from any engagements the system conducts so that it can later be analyzed.[citation needed]

Radar subsystems

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The CIWS has two antennas that work together to engage targets. The first antenna, for searching, is located inside the radome on the weapon control group (top of the white-painted portion). The search subsystem provides bearing, range, velocity, heading, and altitude information of potential targets to the CIWS computer. This information is analyzed to determine whether the detected object should be engaged by the CIWS system. Once the computer identifies a valid target (see details below), the mount moves to face the target and then hands the target over to the tracking antenna at around 4.5 nautical miles (8 km). The track antenna is extremely precise, but views a much smaller area. The tracking subsystem observes the target until the computer determines that the probability of a successful hit is maximized and then, depending on the operator conditions, the system either fires automatically at around 1 nautical mile (2 km) or recommends fire to the operator. While firing 75 rounds per second, the system tracks outgoing rounds and 'walks' them onto the target.[15]

U.S. Navy sailors load tungsten ammunition (white sabots at right) and offload dummy ammunition (left).

Gun and ammunition handling system

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The Block 0 CIWS mounts (hydraulic driven) fired at a rate of 3,000 rounds per minute and held 989 rounds in the magazine drum.[3] The Block 1 CIWS mounts (hydraulic) also fired at 3,000 rounds per minute with an extended magazine drum holding 1,550 rounds. The Block 1A and newer (pneumatic driven) CIWS mounts fire at a rate of 4,500 rounds per minute with a 1,550-round magazine. The velocity of the rounds fired is about 3,600 feet per second (1,100 m/s). The rounds are armor-piercing tungsten penetrator rounds or depleted uranium with discardable plastic sabots. The Phalanx CIWS 20 mm rounds are designed to destroy a missile's airframe and make it non-aerodynamic, thus keeping shrapnel from the exploding projectile to a minimum, effectively keeping secondary damage to a minimum. The ammunition handling system has two conveyor belt systems. The first takes the rounds out of the magazine drum to the gun; the second takes empty shells or unfired rounds to the opposite end of the drum.

The 20 mm APDS rounds consist of a 15 mm (0.59 in) penetrator encased in a plastic sabot and a lightweight metal pusher.[16] Rounds fired by the Phalanx cost around $30 each and the gun typically fires 100 or more when engaging a target.[citation needed]

CIWS contact target identification

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The CIWS does not recognize identification friend or foe, also known as IFF. The CIWS has only the data it collects in real time from the radars to decide if the target is a threat and to engage it. A contact must meet multiple criteria for the CIWS to consider it a target. [citation needed] These criteria include:

A sailor sits at a CIWS Local Control Panel (LCP) during a general quarters drill.
  1. Is the range of the target increasing or decreasing in relation to the ship? The CIWS search radar sees contacts that are out-bound and discards them. The CIWS engages a target only if it is approaching the ship.
  2. Is the contact capable of maneuvering to hit the ship? If a contact is not heading directly at the ship, the CIWS looks at its heading in relation to the ship and its velocity. It then decides if the contact can still perform a maneuver to hit the ship.
  3. Is the contact traveling between the minimum and maximum velocities? The CIWS has the ability to engage targets that travel in a wide range of speeds; however, it is not an infinitely wide range. The system has a target maximum-velocity limit. If a target exceeds this velocity, the CIWS does not engage it. It also has a target minimum-velocity limit, and does not engage any contact below that velocity. The operator can adjust the minimum and maximum limits within the limits of the system.

There are many other subsystems that together ensure proper operation, such as environmental control, transmitter, mount movement control, power control and distribution, and so on. It takes six to eight months to train a technician to maintain, operate, and repair the CIWS.[citation needed]

Incidents

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Drone exercise accidents

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On 10 February 1983, USS Antrim was conducting a live-fire exercise off the East Coast of the United States using the Phalanx against a target drone. Although the drone was successfully engaged at close range, the debris of the destroyed target bounced off the sea surface and struck the ship, causing significant damage and fire from the drone's residual fuel and killing a civilian instructor aboard the ship.

On 13 October 1989, USS El Paso was conducting a live-fire exercise off the East Coast of the United States using the Phalanx against a target drone. The drone was successfully engaged, but as the drone fell to the sea, the CIWS re-engaged it as a continued threat to El Paso. Rounds from the Phalanx struck the bridge of USS Iwo Jima, killing one officer and injuring a petty officer.[17]

Iran–Iraq War

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Stark listing after being hit.
See also: USS Stark (FFG-31) § Missile attack

On 17 May 1987, during the Iran–Iraq War, which the US was observing as a non-combatant, an Iraqi Dassault Mirage F1 fighter[18] fired two Exocet missiles at what was deemed to be a suitable target, but was the American frigate USS Stark.

The Phalanx CIWS remained in standby mode and the Mark 36 SRBOC countermeasures were not armed, as no attack had been expected. Both missiles struck the port side of the ship near the bridge. 37 United States Navy personnel were killed and 21 wounded. Iraq apologized and paid compensation for this unintentional attack.[19]

Iraqi missile attack in 1991 Gulf War

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On 25 February 1991, during the first Gulf War, the Phalanx-equipped frigate USS Jarrett was a few miles from the U.S. Navy battleship USS Missouri and the Royal Navy destroyer HMS Gloucester. An Iraqi missile battery fired two Silkworm anti-ship missiles (often referred to as the Seersucker); Missouri responded by firing its SRBOC chaff countermeasures. The Phalanx system on Jarrett, operating in automatic target-acquisition mode, fixed on Missouri's chaff and fired a burst of rounds, of which four hit Missouri, 2 to 3 nautical miles (roughly 3+1⁄2 to 5+1⁄2 km) from Jarrett at the time. There were no injuries on Missouri, and the Iraqi missiles were destroyed by Sea Dart missiles fired by Gloucester.[20]

Pearl Harbor accidental discharge

[edit]

On May 5, 1994, the port side Phalanx onboard the USS Lake Erie accidentally fired two depleted uranium rounds while the ship was at its berth at Pearl Harbor, Hawaii. Sailors were conducting a firing circuit test as part of routine maintenance on the CIWS system at the time. A Judge Advocate General investigation concluded that required CIWS pre- and post-firing inspections had not been properly conducted and the rounds had gone undetected in the ammunition drive. It is believed by the Navy that the rounds fell in an undeveloped mountainous area near Aiea, HI. There were no reports of any injuries or property damage as a result of the accidental discharge.[21][22][23]

JMSDF mounted Phalanx CIWS

Accidental shoot-down of US aircraft by Japanese ship

[edit]

On 4 June 1996, a Phalanx operated by the JMSDF accidentally shot down a US A-6 Intruder from the aircraft carrier USS Independence that was towing a radar target during gunnery exercises about 1,500 mi (2,400 km) west of the main Hawaiian island of Oahu. The Asagiri-class destroyer JDS Yūgiri locked onto the Intruder instead of the target, or tracked up the tow cable after acquiring the towed target. The aircraft's two-man crew ejected safely.[24] A post-accident investigation concluded that Yūgiri's gunnery officer gave the order to fire before the A-6 was out of the CIWS engagement envelope.[25][26]

Red Sea crisis

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Main article: Red Sea crisis

On 30 January 2024, Houthis fired an anti-ship cruise missile toward the Red Sea. The missile came within a mile of the Arleigh Burke-class destroyer USS Gravely. The Phalanx CIWS aboard Gravely was used to shoot down the missile. This was the first time the Phalanx CIWS was used to down a Houthi-fired missile.[27] No damage or injuries were reported.[28][29]

Centurion C-RAM

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See also: Centurion C-RAM
Centurion C-RAM

Seeking a solution to continual rocket and mortar attacks on bases in Iraq, the U.S. Army requested a quick-to-field antiprojectile system in May 2004, as part of its Counter-Rocket, Artillery, Mortar initiative.[30] The result of this program was the "Centurion". For all intents and purposes a terrestrial version of the Navy's CIWS, the Centurion was rapidly developed,[31] with a proof-of-concept test in November that same year. Deployment to Iraq began in 2005,[30][32] where it was set up to protect forward operating bases and other high-value sites in and around the capital, Baghdad.[33] Israel purchased a single system for testing purposes, and was reported[34] to have considered buying the system to counter rocket attacks and defend point military installations. However, the swift and effective development and performance of Israel's indigenous Iron dome system has ruled out any purchase or deployment of Centurion. Each system consists of a modified Phalanx 1B CIWS, powered by an attached generator and mounted on a trailer for mobility. Including the same 20 mm M61A1 Gatling gun, the unit is likewise capable of firing 4,500 20 mm rounds per minute.[6][35] In 2008, there were more than 20 C-RAM systems protecting bases in the U.S. Central Command area of operations. A Raytheon spokesman told the Navy Times that 105 attacks were defeated by the systems, most of them involving mortars. Based on the success of Centurion, 23 additional systems were ordered in September 2008.[36]

Like the naval (1B) version, Centurion uses Ku-band radar and FLIR[37][38] to detect and track incoming projectiles, and is also capable of engaging surface targets, with the system able to reach a minus-25-degree elevation.[37] The Centurion is reportedly capable of defending a 0.5 mi2 (1.3 km2) area.[39] One major difference between the land- and sea-based variants is the choice of ammunition. Whereas naval Phalanx systems fire tungsten armor-piercing rounds, the C-RAM uses the 20 mm HEIT-SD (High-Explosive Incendiary Tracer, Self-Destruct) ammunition, originally developed for the M163 Vulcan Air Defense System.[31][40] These rounds explode if they impact a target, but if they miss they self-destruct on tracer burnout, greatly reducing the risk of collateral damage from misses.[31][40]

Operators

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Phalanx CIWS and Bofors 40mm L70 Gun aboard ROCN Di Hua (PFG-1206)
Phalanx LPWS conducts a test fire system at Bagram Air Field, Afghanistan on March 1, 2014.
Phalanx LPWS during the battalion's live fire exercise on Fort Campbell, Kentucky.
Map with Phalanx CIWS users in blue and former users in red

Current operators

[edit]

 Australia[41][42]

 Bahrain[41]

 Canada[41]

 Chile

 Ecuador

 Egypt[43]

 Greece[44]

 Israel[41]

 Japan[43]

 Mexico[45]

 New Zealand[41]

 Pakistan[41]

 Poland[41]

 Portugal[43]

 Saudi Arabia[41]

South Korea[46]

 Thailand[47]

 Turkey

 Taiwan (13 sets MK15 Phalanx Block 1B Baseline 2, 8 set is for upgrading the current Block 0 to MK15 Phalanx Block 1B Baseline 2, total cost: 0.416B with 260K MK 244 MOD 0 armor piercing bullet, Baseline2 is the newest model in Block 1B on 11/2016)[41][1]

 United Kingdom[43]

 United States[43]

Former deployment

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 Australia

 Canada

 India[50]

 Japan

 Malaysia

 New Zealand

 Pakistan

 Thailand

 Taiwan

 United Kingdom

 United States

Former operators

[edit]

 Afghanistan[41][51]

Specifications (Block 1A/B)

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  • Gun: 1× 20 mm M61A2 Vulcan 6-barreled Gatling cannon[3]
  • Height: 15.5 ft (4.7 m)
  • Weight: 12,500 lb (5,700 kg), later models 13,600 lb (6,200 kg)[2]
  • Elevation: −25° to +85°
  • Muzzle velocity: 3,600 ft/s (1,100 m/s)
  • Rate of fire: 4,500 rounds/minute
  • Maximum burst size: 1000 rounds
  • Ammunition capacity: 1,550 rounds
  • Radar: Ku band
  • Cost: $12 Million[52]
  • Target Mach: 2.[53]

Similar systems

[edit]

References

[edit]
[edit]
Revisions and contributorsEdit on WikipediaRead on Wikipedia

Phalanx CIWS

View on Grokipedia
from Grokipedia
The Phalanx Close-In Weapon System (CIWS), designated Mk 15, is a radar-guided 20 mm Gatling gun-based automated defense system designed to provide rapid-reaction protection for naval vessels against anti-ship missiles, , and asymmetric threats such as small boats and unmanned aerial systems. It autonomously conducts search, detection, threat evaluation, tracking, engagement, and kill assessment without requiring external inputs, integrating with the host ship's combat management system for enhanced . Developed in the with production commencing in for the initial Block 0 variant, the system achieved its first operational deployment aboard USS Coral Sea in 1980, marking a significant advancement in point-defense capabilities by enabling engagements at speeds exceeding human reaction times. Subsequent upgrades, including Block 1 in 1988 and Block 1B in 1999, incorporated electro-optical sensors for improved performance against littoral and low-observable threats, along with optimized firing rates of up to 4,500 rounds per minute using armor-piercing discarding sabot from a 1,550-round . The has demonstrated , such as intercepting a Houthi targeting , underscoring its role as a critical last-line defense. Installed on all U.S. Navy classes and exported to 24 allied nations, the system totals over 900 units deployed worldwide, with land-based variants adapted for U.S. Army use in counter-rocket, , and mortar roles. Its defining characteristics include the M61A1 Vulcan and compact design weighing approximately 13,600 pounds for Block 1B configurations, prioritizing reliability and minimal crew intervention in high-threat environments.

Development History

Origins and Initial Requirements

The development of the Phalanx Close-In Weapon System (CIWS) originated in the late 1960s amid growing U.S. Navy concerns over the vulnerability of surface ships to sea-skimming anti-ship missiles (ASMs). The 1967 sinking of the Israeli destroyer INS Eilat by Egyptian-fired Soviet SS-N-2 Styx missiles during the demonstrated the lethal effectiveness of low-altitude, fast-approaching ASMs launched from small vessels, exposing limitations in existing shipboard defenses like surface-to-air missiles (SAMs), which struggled against terminal-phase threats penetrating outer layers. This event, combined with the emergence of Soviet Charlie-class submarines armed with SS-N-9 Siren missiles, underscored the need for a dedicated point-defense system as a final automated barrier against ASMs, , and emerging littoral threats that could evade longer-range interceptors. Initial U.S. Navy requirements emphasized a self-contained, -guided automated system capable of independent detect-track-engage operations with minimal crew input, prioritizing rapid response to saturate incoming projectiles in the final 1-2 miles of approach. The system was to employ a 20 mm derivative—adapted from the Army's M163 Vulcan Air Defense System—for a high exceeding 3,000 rounds per minute, using armor-piercing discarding sabot (APDS) penetrators to reliably destroy missile warheads via kinetic impact rather than explosive proximity fuzes. Detection goals included ranges of approximately 10-16 miles, with engagement envelopes tailored to counter low-flying, maneuvering targets like the or , while ensuring the mount weighed under 13,500 pounds for compatibility with carriers, cruisers, and destroyers. , leveraging existing Vulcan technology, received early development funding, culminating in a July 1974 contract for operational test models. These requirements reflected a first-principles focus on causal : overwhelming threats with sheer projectile volume to achieve probabilistic kills in seconds, bypassing human reaction delays and electronic jamming vulnerabilities observed in prior basic point-defense systems (BPDMS) tested around 1967. The aimed for full to handle salvos of multiple ASMs, with the system designed as an "inner layer" complement to broader defenses, not a standalone solution, ensuring high reliability under combat stress without reliance on ship-wide power or .

Prototyping and Testing Phase

The Phalanx CIWS prototyping phase began in the early 1970s under ' Pomona Division, focusing on an automated radar-guided gun system to counter anti-ship missiles. The initial prototype was installed aboard the USS King (DLG-10/DDG-41) in 1973 for at-sea trials. These tests assessed the system's detection, tracking, and engagement capabilities against simulated threats, revealing the need for enhancements in reliability and performance. Subsequent refinements led to additional prototype iterations, including a unit mounted on the decommissioned USS Bigelow (DD-942) in 1975 for land-based testing. By 1977, a underwent operational test and evaluation (OT&E) aboard USS Bigelow, demonstrating effectiveness in engaging subsonic drone targets at ranges up to 2 kilometers. The system exceeded requirements for maintenance, reliability, and lethality during these trials, with successful intercepts validating its role as a point-defense . Testing incorporated both live-fire engagements and simulated scenarios to refine the fire control algorithms and gun stabilization. Results from the 1973-1977 evaluations confirmed the Phalanx's ability to autonomously detect, track, and destroy incoming threats, paving the way for production approval in September 1977.

Initial Deployments and Early Feedback

A Phalanx CIWS was installed aboard the U.S. Navy destroyer USS King (DLG-10) in August 1973 for initial at-sea evaluation. This marked the system's first operational deployment, though further development was required following the tests. Another underwent land-based and shipboard trials, including mounting on the decommissioned destroyer USS Wallace L. Lind (DD-703) in 1975. Pre-production operational testing and evaluation occurred aboard USS Bigelow (DD-942) in 1977, where the system demonstrated performance exceeding Navy specifications for maintenance, reliability, and availability. These results led to approval for full-rate production in 1978. The first production Block 0 systems were delivered in 1979 and installed on aircraft carriers USS America (CV-66) and USS Coral Sea (CV-43) in 1980, representing the initial fleet-wide deployment. Early operator feedback highlighted the system's autonomous operation and rapid response capabilities, though integration challenges with shipboard systems prompted refinements in subsequent installations. No combat engagements occurred during this phase, with feedback primarily derived from live-fire exercises against drone and missile surrogates, confirming effective threat neutralization at close ranges.

System Architecture

Sensor and Radar Components

The Phalanx CIWS incorporates a self-contained search and track system for autonomous detection, evaluation, and engagement of incoming threats such as anti-ship missiles and . The search operates in the Ku-band frequency range (approximately 12-18 GHz) and employs digital (MTI) processing to distinguish moving targets from sea clutter and background noise during wide-area surveillance. Once a potential is identified, the system transitions to the track , also Ku-band based, which utilizes pulse-Doppler monopulse techniques for high-precision angular measurement and velocity determination, enabling accurate fire control solutions up to engagement ranges of about 1.5 kilometers. These are mounted on a swiveling turret, providing 360-degree coverage with limits suited to low-altitude threats, and are designed for rapid reaction times under 5 seconds from detection to firing. In the Block 1B variant, introduced in 1999, an integrated (FLIR) was added to complement the s, offering stabilized thermal imaging for detection and classification of surface threats like small boats in scenarios, particularly in conditions where performance may be degraded by or electronic countermeasures. The FLIR provides high-definition infrared imaging, enhancing target identification and enabling manual override modes for operators. This upgrade maintains while expanding the system's versatility without altering the core architecture.

Gun Mechanism and Ammunition Feed

The Phalanx CIWS is armed with the M61A1 Vulcan, a six-barrel 20 mm Gatling-type rotary cannon that fires 20×102 mm projectiles. The gun operates on the external power-driven Gatling principle, with an rotating the barrel cluster and electrically igniting the primers for sustained automatic fire. Early Block 0 and Block 1 variants achieve a cyclic rate of 3,000 rounds per minute using hydraulic drive, while Block 1B and subsequent upgrades employ pneumatic drive to reach 4,500 rounds per minute, enhancing engagement effectiveness against high-speed threats. Ammunition is fed via a linkless integrated into the turret, holding 1,550 rounds ready for immediate use. The system uses armor-piercing discarding sabot (APDS) rounds featuring sub-caliber penetrators optimized for defeating hardened casings; penetrators were initially employed but replaced with in 1988 due to environmental and handling considerations. The feed mechanism automatically indexes rounds from the to the gun's chamber, with spent casings ejected downward to minimize interference with ship operations. Drum reloading involves specialized cassettes that displace dummies with live through a front-loading , enabling rapid replenishment without full disassembly.

Fire Control and Automation Logic

The of the Phalanx CIWS employs an integrated , computer, and servo-controlled mount to automate detection and , enabling rapid response without intervention in automatic mode. The core automation logic sequences through search, detection, evaluation, tracking, firing, and kill assessment phases, prioritizing the nearest high-priority threats such as anti-ship missiles or on collision courses. This process relies on Ku-band —a digital (MTI) search for initial scanning up to the horizon and a Doppler monopulse tracking for precise and range data—to identify contacts against and jamming. Upon detecting a potential target, the digital computer evaluates its status by computing predicted , closing , and impact probability, engaging only if the contact meets criteria for imminent danger, typically initiating fire at approximately 4,000 yards (3.6 km). The then slews the mount to maintain lock using advanced tracking algorithms that accommodate maneuvering targets, calculates ballistic solutions accounting for environmental factors, and fires a controlled burst of 20mm rounds while simultaneously tracking outgoing projectiles to refine aim and predict intercept points. Post-engagement, radar assesses kill effectiveness by monitoring target fragmentation, deviation, or cessation of motion, ceasing fire once the is neutralized or adjusting burst length based on target type. Operational modes include fully automatic for autonomous logic-driven response, semi-automatic for operator confirmation, and manual override, with Block 1B variants adding stations and (FLIR) sensors for visual threat identification to reduce false engagements against asymmetric threats like small boats or drones. Block 1A upgrades introduced high-order language programming for enhanced engagement algorithms, improving discrimination against decoys and support for rolling airframe missiles, while maintaining the system's emphasis on minimal latency in . Integration with shipboard systems allows cueing from external sensors, but the Phalanx retains standalone capability for self-contained operation.

Operational Mechanics

Threat Detection and Prioritization

The Phalanx CIWS utilizes a Ku-band search operating in digital (MTI) mode to perform continuous autonomous scanning from the horizon to vertical elevations, acquiring potential such as anti-ship missiles and at ranges up to 10 nautical miles. This rotates at 90 and discards outbound contacts while initiating evaluation of inbound tracks by analyzing target heading, speed, range, and predicted maneuverability to assess collision potential with the protected vessel. Threat evaluation integrates these parameters to classify objects as high-priority dangers, focusing on those demonstrating trajectories consistent with direct . Upon detection, the system's software assigns prioritization at approximately 5 miles based on threat logic that emphasizes decreasing range, high , and inbound headings, selecting up to the first six validated threats for engagement sequencing. This closed-loop prioritization ensures efficient against salvos, with engagement initiating around 2 miles if the threat remains confirmed on an intercept course. Operators can manually adjust parameters such as speed thresholds in certain modes, though the system defaults to fully autonomous operation for rapid response. In the Block 1B variant, introduced in 1999, an integrated electro-optical sensor suite, including (FLIR), augments detection for asymmetric threats like small surface craft, helicopters, and unmanned systems by providing heat signature analysis and stabilized visual tracking. This enhancement enables operator intervention for visual identification and discrimination between threats and non-threats, such as distinguishing decoys or civilian objects, thereby refining prioritization in complex littoral environments. The tracking , a Ku-band pulse Doppler monopulse unit, then assumes precise guidance for the selected targets, supporting the transition to fire control.

Engagement Sequence and Modes

![Phalanx CIWS firing during an engagement sequence](./assets/US_Navy_101027-N-8913A-252_Rounds_from_a_Mk-15_Phalanx_Close-in_Weapon_System_(CIWS) The Phalanx CIWS engagement sequence integrates search, detection, , tracking, fire control, and kill assessment into an automated process designed for rapid response to incoming anti-ship missiles and low-flying . The system's Ku-band continuously scans for potential threats within a detection range of approximately 5 kilometers (3.1 miles), prioritizing up to six inbound targets based on criteria such as closing velocity exceeding 150 meters per second and projected impact within the ship's vulnerable zone. Upon identifying a hostile , the fire control computer evaluates using algorithms that assess speed, aspect angle, and predicted point of closest approach, rejecting non- like birds or debris through Doppler processing and, in Block 1B variants, (FLIR) confirmation. If validated as a , the system slews the mount to track the target, computing a lead-angle firing solution accounting for projectile ballistics and target motion. Engagement initiates automatically when the closes to within the effective firing of about 2 kilometers (1.2 miles), unleashing a short burst of up to 75 tungsten-penetrator rounds per second from the 20mm to saturate the target's path and achieve a kinetic kill. Post-firing, the Phalanx performs immediate kill assessment by monitoring returns for target breakup or cessation of motion, with FLIR-equipped systems providing visual verification of or plume disruption; successful kills trigger cessation of fire to conserve , while persistent threats prompt re-engagement or handoff to other defenses. The sequence repeats for subsequent threats, limited by magazine capacity of 1,550 rounds supporting roughly 20 seconds of continuous fire across multiple salvos. This closed-loop autonomy minimizes reaction time to under 5 seconds from detection to engagement. Operational modes include fully automatic, where the system independently executes the entire sequence without human intervention; semi-automatic, requiring operator confirmation via station before firing to mitigate false positives; and manual mode, allowing direct operator aiming and triggering for or overridden scenarios. In automatic mode, deployed on U.S. vessels since 1980, the maintains constant vigilance in "ready" status, engaging threats as programmed, though operators can intervene via override switches. Block upgrades, such as 1A and 1B introduced in the and , enhanced mode flexibility with improved processors for faster threat discrimination and integration of electro-optical sensors for surface threats in Phalanx Surface Mode.

Integration with Broader Shipboard Defenses

The Phalanx CIWS serves as the innermost layer in a warship's multi-tiered air and architecture, engaging threats that penetrate outer defenses such as long-range surface-to-air missiles (SAMs) like the SM-6 or , medium-range systems, and electronic countermeasures. This positioning relies on prior interception attempts by shipboard radars and launchers, with Phalanx activating autonomously or via external cues when threats close to within approximately 2 kilometers. In U.S. Navy doctrine, it complements systems like the , which provides early warning via SPY-1 or SPY-6 radars, allowing Phalanx to prioritize verified inbound anti-ship missiles or low-flying aircraft after outer layers fail. Integration occurs primarily through the (SSDS) Mk 2, a combat management framework that fuses data from multiple sensors and effectors across the vessel. Block 1B and later variants include software interfaces, such as adaptive filtering in ADA language, enabling cueing from SSDS or Aegis-derived tracks to reduce false alarms and extend reaction time by handing off targets pre-detection. Conversely, feeds its Ku-band search and data back to the ship's central center, augmenting for other weapons like the Rolling Airframe (RAM) or SeaRAM, which may engage in parallel for redundancy. This bidirectional linkage, tested in live-fire exercises since the , ensures deconfliction to avoid , with defaulting to manual override if integration signals degrade. On non-Aegis platforms, such as frigates or amphibious ships, Phalanx interfaces with legacy systems like the Mark 23 Target Acquisition System (TAS) or standalone radars, often via standardized NTDS (Navy Tactical Data System) links for track sharing. International operators, including the Royal Australian Navy's Hobart-class destroyers, adapt Phalanx into baseline-agnostic architectures by linking it to CEA Technologies' phased-array radars, demonstrating modular plug-and-play compatibility introduced in Block 1A upgrades around 1990. Empirical evaluations from Red Sea engagements in 2023-2024 highlight this synergy, where Phalanx downed Houthi drones after Aegis intercepts depleted missile stocks, underscoring its role in conserving layered assets under saturation attacks.

Variants and Modernizations

Core Block Upgrades

The Phalanx CIWS originated with the Block 0 configuration, operational from , optimized primarily for intercepting inbound anti-ship cruise missiles using a Ku-band for detection and a 20 mm for kinetic defeat. This baseline featured a 1,000-round magazine capacity and automated fire control limited to aerial threats at low to medium altitudes. Block 1 upgrades, introduced in 1988 with the first installation on USS Wisconsin (BB-64), extended engagement range to high-altitude missiles through an improved antenna design and increased ammunition capacity by 50% to 1,500 rounds. Additional enhancements included a multiple pulse repetition frequency search radar, expanded radar cross-section lookup tables for diverse targets, and an upgraded fire control processor for faster processing. Block 1A followed with software modifications to refine tracking algorithms and engagement logic, improving reliability against maneuvering threats. The Block 1B variant, first deployed on USS Underwood (FFG-36) in 1999, incorporated a stabilized electro-optical forward-looking infrared (FLIR) sensor to enable detection and engagement of surface threats such as small high-speed boats, in addition to aerial targets including helicopters and unmanned aerial vehicles. This upgrade added Phalanx Surface Mode (PSuM), allowing manual operator override via remote video terminals for threat identification, while optimized gun barrels (OGB) with electric drive mechanisms reduced maintenance needs and sustained firing rates up to 4,500 rounds per minute. By fiscal year 2015, the U.S. Navy had standardized all systems to Block 1B or later. Subsequent Block 1B Baseline 2 refinements, implemented from around 2020, enhanced electro-optical and radiofrequency tracking for closer integration with shipboard command systems, as seen in contracts for allied navies like Australia's upgrades to Hobart-class destroyers. In 2025, the U.S. Navy awarded Raytheon a $205 million contract for ongoing sustainment and upgrades, focusing on component overhauls to maintain effectiveness against evolving asymmetric threats without altering core kinematics. These iterative core block modifications have prioritized empirical improvements in sensor fusion and automation over radical redesigns, reflecting operational data from deployments emphasizing layered defense reliability.

Hybrid and Specialized Variants

The SeaRAM system constitutes a hybrid variant of the Phalanx CIWS, replacing the 20 mm Vulcan cannon with an 11-cell vertical launch system for RIM-116 Rolling Airframe Missiles while incorporating the Phalanx Block 1B's Ku-band search and track radar, forward-looking infrared (FLIR) sensor, and closed-loop fire control architecture for automated threat detection, evaluation, and engagement. This design leverages the Phalanx's proven sensor suite to guide passive radio-frequency and infrared-homing missiles, achieving intercepts at ranges exceeding 5 km against anti-ship missiles, aircraft, and surface craft, compared to the gun-based Phalanx's effective range of approximately 1.6 km. Initial U.S. Navy deployment occurred on USS Independence (LCS-2) in 2010, with full operational capability declared in 2013; by 2021, over 20 systems were installed across littoral combat ships, amphibious vessels, and destroyers, often complementing existing Phalanx mounts for layered defense. Specialized naval adaptations of the include configurations optimized for asymmetric threats, such as the Block 1B Surface Mode variant, which emphasizes electro-optical identification and tracking of small boats and unmanned surface vessels through stabilized video and FLIR integration, enabling operator intervention via remote control stations for reduced false engagements in cluttered littoral environments. These systems, fielded since 2003, incorporate software updates for enhanced discrimination between threats and non-combatants, drawing on empirical data from exercises showing improved hit probabilities against low-altitude, slow-moving targets. Foreign operators have pursued specialized integrations, such as Japan's Maritime Self-Defense Force mounting with indigenous fire control links on Akizuki-class destroyers for coordinated engagements with Type 03 medium-range missiles, commissioned starting in 2012.

Recent Sustainment and Enhancement Programs

In September 2025, the U.S. Navy awarded RTX's Raytheon a $205 million contract modification to support the continued production, upgrades, overhauls, conversions, and delivery of equipment for the Mk 15 Phalanx CIWS, as part of a multi-year sustainment initiative across the surface fleet. This program addresses wear from operational use and evolving threats, including asymmetric dangers like drones and small surface craft, by ensuring system reliability through component replacements and performance enhancements. The initiative builds on the Block 1B baseline, which incorporates stabilized electro-optical/ sensors for improved target identification in surface and air modes, with recent efforts focusing on overhauls to maintain firing rates of up to 4,500 rounds per minute using 20mm penetrators. Conversions under the program upgrade legacy systems to this configuration, extending operational life while integrating with shipboard networks for layered defense. These sustainment activities, managed by , prioritize depot-level repairs and supply chain resilience to counter missile salvos and low-flying threats, with the Navy exploring palletized variants for flexible deployment on non-traditional platforms amid rising near-peer competition. Empirical data from prior engagements validates the need for such enhancements, as Phalanx's radar-guided automation has demonstrated effectiveness against high-speed inbound projectiles, though overhauls mitigate degradation in sensor accuracy and barrel life.

Combat Performance and Incidents

Documented Successes in Engagements

The Phalanx CIWS achieved its first confirmed combat kill on January 30, 2024, when the Arleigh Burke-class destroyer USS Gravely (DDG-107) engaged and downed an incoming Houthi anti-ship in the . The missile, launched by Yemen's Houthi rebels, approached within approximately one (1.6 km) of the ship before the system's 20 mm fired a burst of tungsten rounds, successfully neutralizing the threat as a final line of defense after longer-range interceptors were employed. Subsequent engagements in the demonstrated the system's utility against Houthi drone swarms and during ongoing operations against Iran-backed attacks on international shipping. On May 5, 2025, (RTX), the manufacturer, confirmed another successful intercept of a Houthi targeting a U.S. , underscoring the system's effectiveness in high-threat environments where threats penetrate outer defenses. In November 2024, the destroyer utilized during an extended "hours-long shoot-out" with Houthi forces, contributing to the repulsion of multiple drone and salvos amid intensified rebel assaults. These incidents represent the Phalanx's primary documented successes in live naval combat, primarily against subsonic or slower threats like Houthi cruise missiles and unmanned aerial vehicles, where its autonomous radar-guided fire control enables rapid response within seconds of detection. Prior to these events, no verified combat intercepts by the naval Phalanx variant were publicly confirmed, though extensive testing and simulations had validated its capability against anti-ship missiles and . The engagements highlight the system's role in layered defense architectures, where it serves as a kinetic "point defense" weapon after missile-based systems like the SM-2 or ESSM are expended or bypassed.

Failures, Accidents, and Friendly Fire Events

On May 17, 1987, during the Iran-Iraq War, the (FFG-31) was struck by two anti-ship missiles fired by an Iraqi F1 aircraft, resulting in 37 sailors killed and 21 wounded. The ship's Phalanx CIWS failed to engage the incoming missiles, which flew low over the horizon and were detected late by ; the system had experienced intermittent maintenance issues in the preceding weeks, including failures in systems operability tests, and was reportedly placed in standby mode to minimize emissions in the crowded operating environment. During Operation Desert Storm on February 25, 1991, the USS Jarrett (FFG-33)'s Phalanx CIWS, operating in automatic engagement mode amid a perceived Silkworm missile threat, mistook chaff deployed by the nearby battleship USS Missouri (BB-63) for an incoming target and fired a short burst of 20mm rounds. Several stray projectiles struck the Missouri, with one penetrating a bulkhead into an interior passageway and another hitting the ship's exterior, though no personnel were injured in the incident. On June 3, 1996, during the RIMPAC multinational exercise off , the Japanese destroyer JS Yūgiri's Phalanx CIWS engaged and shot down a U.S. A-6E Intruder from , which was towing a . The crashed into the ocean, but both crew members ejected safely and were rescued; a post-incident investigation determined that the destroyer's gunnery officer had ordered firing prematurely, before the Intruder exited the CIWS engagement envelope, overriding safety protocols. These events underscore operational challenges with the Phalanx CIWS, including vulnerability to low-altitude threats when not fully activated and risks of erroneous engagements in cluttered environments or during exercises, where automated targeting can misidentify decoys, , or non-hostile assets as threats without sufficient human oversight.

Empirical Effectiveness Evaluations and Debates

Testing of the Phalanx CIWS in the 1970s demonstrated high effectiveness against representative threats, with the system destroying all inbound missiles during evaluations aboard USS Alfred A. Cunningham in 1975 and exceeding reliability and maintenance specifications under jamming and noise conditions on USS Bigelow in 1977. Block 1B variants achieved availability rates of 72-81% in fiscal years 1997-1999, indicating improved operational reliability over earlier models following upgrades to address corrosion and maintenance issues. In land-based C-RAM deployments, the system downed mortar rounds in starting May 2005, providing empirical evidence of utility against in ground defense roles. Combat data remains sparse for naval applications due to the system's role as a last-ditch defense, with few confirmed engagements against s. However, incidents like the 1987 Exocet attack on saw the Phalanx on standby without engagement, contributing to the ship's severe damage, while a 1991 event involving USS Jarrett resulted in the system firing on a chaff cloud and inadvertently striking in . Debates center on the system's limitations against evolving threats, with analyses concluding it cannot effectively intercept hypersonic missiles under current configurations due to insufficient reaction time and . Critics highlight vulnerabilities to saturation attacks, given the 1,550-round magazine depletes in approximately 20 seconds at full 4,500 rounds-per-minute rate, and an effective engagement range of about 1.5 km, which allows debris from downed supersonic to potentially damage the host vessel. Proponents emphasize its value in layered defenses, where it reduces and functionality even if not achieving clean kills, and note successes against subsonic threats, UAVs, and small boats in trials. Reliability enhancements, such as those implemented after early fielding issues, have been credited with sustaining its role, though some assessments question its standalone adequacy against swarm tactics or sea-skimming maneuvers without integration with longer-range systems.

Land-Based and Derivative Systems

Centurion C-RAM Adaptation

The C-RAM, also known as the Land Phalanx Weapon System (LPWS), represents the adaptation of the naval CIWS Block 1B for ground-based counter-rocket, , and mortar defense. Developed by in 2004 amid vulnerabilities exposed during the , the system integrates the Phalanx's 20mm rotary cannon with radar-guided detection and tracking to automatically engage incoming projectiles. Mounted on mobile platforms such as Oshkosh HEMTT trucks for rapid deployment, it provides point defense for forward operating bases and high-value assets, operating effectively within a approximately 2 km radius. Initial deployment occurred in during summer 2005, where units protected sites around against insurgent-fired rockets and mortars. The system employs the Phalanx's Ku-band search and track to detect threats at low altitudes, cueing the to fire bursts of tungsten penetrator rounds at rates up to 4,500 per minute to fragment incoming projectiles mid-air. According to a representative, defeated 105 attacks in , primarily mortars, demonstrating practical utility in asymmetric conflict environments despite its origins in anti-missile naval roles. Produced in collaboration with for sensors and Oshkosh for vehicle integration, the emphasizes automation to minimize operator intervention, though it can incorporate external cueing from other radars for extended detection. Sustainment efforts continue, with RTX (formerly ) securing a U.S. in June 2025 for maintenance and upgrades to ensure reliability against evolving threats like drones. While effective for short-range point defense, its high consumption—approximately $3,500 per second of —necessitates careful integration with layered defenses.

Performance in Ground Defense Roles

The land-based adaptation of the Phalanx CIWS, known as Centurion C-RAM, was first operationally deployed in in 2005 to counter rocket, artillery, and mortar threats to forward operating bases. This system integrates the Block 1B gun module with enhanced electro-optical/infrared sensors for detecting low-flying, surface-launched projectiles, enabling automatic engagement within seconds of threat detection. In and , C-RAM's sense-and-warn subsystems provided timely alerts for over 2,500 incoming rocket and mortar attacks, allowing personnel to take cover and reducing casualties from . Combat intercepts demonstrated variable effectiveness against sporadic insurgent launches. In , the system reportedly achieved 70-80% knockdown rates for rockets and mortar shells in operational use, leveraging its 20 mm penetrator rounds fired at 3,000-4,500 rounds per minute to fragment threats in mid-air. Pre-deployment tests confirmed a 60-70% shoot-down capability against representative threats, though real-world performance depended on factors like launch volume and environmental conditions. By 2020, units continued engaging rockets over Baghdad's , illustrating sustained utility against persistent low-tech threats post-major combat operations. Limitations emerged in scenarios involving multiple simultaneous projectiles or faster-moving threats. Analysis of specific engagements, such as video-documented firings, indicated success rates as low as 20-50% when threats evaded initial bursts due to clutter or velocity mismatches, highlighting the system's optimization for single or low-density attacks rather than massed barrages. expenditure—up to 1,500 rounds per —necessitated rapid reloading, constraining prolonged defenses without logistical support. Adaptations extended to drone intercepts, with C-RAM downing incoming unmanned aerial vehicles in at least one documented base protection event. Overall evaluations affirm its role in layered ground defense, prioritizing area protection over precision against high-volume fire.

Global Operators and Deployments

Primary Naval Operators

The United States Navy serves as the primary operator of the Phalanx CIWS, which it developed through Raytheon under a program initiated in the early 1970s to counter anti-ship missile threats. The system achieved initial operational capability aboard the USS King (DLG-10) for testing in 1973 and entered full service on the USS Coral Sea (CV-43) in 1980, subsequently becoming standard equipment on all surface combatant classes, including aircraft carriers, guided-missile cruisers, destroyers, littoral combat ships, and amphibious assault vessels. This widespread integration provides an automated terminal defense layer against incoming missiles, fixed-wing aircraft, rotary-wing threats, and small surface vessels, with ongoing sustainment contracts ensuring reliability across the fleet; for instance, a $205 million award in September 2025 supported production and upgrades for continued deployment. Allied navies constitute secondary but significant operators, with the installed on warships of 24 partner nations to bolster point defense capabilities compatible with U.S. systems. Prominent among these are the Royal Australian Navy, which equips its surface combatants including Anzac-class frigates and Hobart-class destroyers; the , featuring the system on Akizuki-class destroyers and other major vessels; and the Royal Navy, which adopted it post-Falklands War for Type 23 frigates and Type 45 destroyers as a last-line defense against air and surface threats. These deployments reflect export successes driven by the system's proven autonomy in search, detection, tracking, and engagement functions, though operational numbers vary by fleet size and remain classified in detail for most users.

Export and Non-US Deployments

The Phalanx CIWS has been exported to allied navies through U.S. , with installations on warships of approximately 24 nations as of 2020. Australia's employs Phalanx Block 1B systems on Hobart-class destroyers and supply ships, including successful live-fire trials aboard HMAS Supply during a 2022 regional deployment. Canada's integrates on Halifax-class frigates for close-in defense. Japan's Maritime Self-Defense Force received U.S. approval for Phalanx Block 1B in 2018, incorporating the system on advanced destroyers like the ASEV-class for enhanced anti-missile protection. The United Kingdom's mounts Phalanx on select surface combatants, including Type 23 frigates, as a supplementary point-defense layer. South Korea pursued acquisition of two Phalanx Block 1B units via FMS approval in 2020 for KDX-III Batch II destroyers, with procurement requests formalized in 2022. Other operators include the navies of , , , and , with Thailand installing Block 1B on the Bhumibol Adulyadej-class as the sole Southeast Asian adopter.

Technical Specifications

Block 1B Baseline Parameters

The Block 1B configuration of the Close-In Weapon System (CIWS) builds on prior by integrating capabilities for engaging both anti-ship missiles and asymmetric surface threats, such as small boats and unmanned surface vessels, through the addition of a stabilized electro-optical/infrared (EO/IR) sensor suite including (FLIR). This baseline entered service after operational evaluation on USS Underwood in 1999 and deployment on USS Taylor in 2000, featuring an optimized (OGB) for improved dispersion and enhanced lethality cartridges (ELC) with 50% greater penetration mass compared to earlier ammunition. Key baseline parameters include a total system weight of 13,600 pounds (6,169 kg), encompassing the mount, , radar, and magazine. The employs an M61A1 20 mm Vulcan 6-barreled Gatling with an OGB extending the bore length to approximately 78 inches (1.981 m), enabling selectable fire rates of 3,000 rounds per minute for surface targets or 4,500 rounds per minute for aerial threats. capacity stands at 1,550 rounds of ELC in a , supporting sustained bursts with around 3,600 ft/s (1,100 m/s).
ParameterSpecification
Effective Range1,625 yards (1,490 m) maximum
Elevation Limits-25° to +85°
Traverse150° from either side of centerline
RadarKu-band digital (search); Doppler monopulse (track)
Power Requirements440 VAC, 60 Hz, three-phase; 18 kW (search mode), 70 kW (track mode)
SensorsIntegrated FLIR/EO for visual identification and tracking
These parameters enable autonomous detection, tracking, engagement, and kill assessment, with optional manual override via stations for target verification. The system's height approximates 4.7 meters, optimized for shipboard integration on destroyers, frigates, and carriers. Block 1B's dual-mode operation addresses limitations in earlier blocks against low, slow, or surface threats, though it retains the core radar-guided autonomy for high-speed intercepts.

Comparative Systems

Peer Close-In Weapon Systems

The , developed by (formerly Hollandse Signaalapparaten), employs a 30 mm GAU-8/A Avenger seven-barrel mounted in a radar-directed turret for autonomous detection, tracking, and engagement of incoming anti-ship missiles, , and surface threats. It achieves a of 4,200 rounds per minute using armor-piercing discarding sabot (APDS) or high-explosive incendiary (HEI) optimized for missile penetration, with an effective engagement range of up to 3.5 km against aerial targets. The system integrates search and tracking radars with electro-optical sensors for operation in adverse conditions, and has been adopted by navies including the , , and several Asian operators since its introduction in the . The , a Soviet-era design produced by the Tulsky Oruzheiny Zavod, features a 30 mm GSh-6-30 six-barrel in a stabilized mount, delivering 4,000 to 5,000 rounds per minute from a 2,000-round magazine to counter low-flying aircraft, missiles, and small surface craft. Its and optical supports an effective range of 4 km for air targets and up to 5 km maximum, with the weapon's higher caliber compared to 20 mm systems providing greater projectile mass for improved lethality against hardened threats. Widely exported and deployed on over 500 platforms across Russian and allied fleets, including Indian and Vietnamese navies, the AK-630 often operates in pairs for 360-degree coverage. The Kashtan (Kortik) CIWS, manufactured by , combines two 30 mm GSh-6-30KD six-barrel guns—firing at a combined rate of up to 10,000 rounds per minute—with eight 9M311 surface-to-air missiles in vertical launch tubes for layered defense against missiles and aircraft at ranges extending to 10 km for missiles and 5 km for guns. The system's multi-sensor suite, including and trackers, enables salvo firing and prioritization of threats, with upgraded Kashtan-M variants featuring improved gun velocity and adverse-weather optics. Primarily equipping Russian Kirov-class cruisers, Admiral Gorshkov-class frigates, and exported to and , it represents a hybrid approach to extend engagement envelopes beyond pure gun systems. Other notable peers include China's Type 730 (H/PJ-12), a seven-barrel 30 mm system with 4,600–5,800 rounds per minute and phased-array guidance, deployed on Type 054A frigates and Type 052D destroyers for ranges up to 3–5 km. These systems collectively provide navies with alternatives emphasizing larger calibers for enhanced kinetic impact or integrated missiles for standoff capability, though empirical combat data remains limited primarily to tests and rare engagements.

Relative Advantages and Vulnerabilities

The Phalanx CIWS excels in automation and rapid response compared to less integrated peer systems like the , leveraging a self-contained suite for detection, tracking, and engagement that surpasses human reaction capabilities, with a fire rate of up to 4,500 rounds per minute from its 20mm . This enables effective interception of high-speed threats such as anti-ship missiles and at close range, as demonstrated in operational testing where it has neutralized incoming shells, rockets, and mortars. Relative to the , Phalanx offers a smaller deck footprint and reduced structural penetration requirements, facilitating easier integration on diverse naval platforms without compromising core anti-air performance. Its Block 1B upgrade further enhances versatility with an for surface threat engagement, such as small boats, outperforming radar-only systems in cluttered littoral environments. Despite these strengths, remains vulnerable to saturation attacks, as its single gun turret and sequential firing limit it to engaging approximately one to two threats concurrently, allowing coordinated salvos of anti-ship missiles to overwhelm it before depletion—typically after 10-15 bursts from its 1,550-round magazine. The system's effective range of 2-3 kilometers confines it to point defense, rendering it ineffective against threats neutralized earlier by longer-range systems like the RIM-116 RAM, which can intercept supersonic missiles at greater standoff distances. Compared to Goalkeeper's 30mm higher-velocity projectiles, 's penetrator rounds exhibit reduced lethality against sea-skimming missiles due to lower (approximately 1,100 m/s versus 1,200+ m/s), potentially allowing some low-altitude penetrations in high-sea-state conditions. Additionally, while robust against electronic countermeasures in testing, its radar-dependent operation can be degraded by advanced jamming or decoys, necessitating reliance on layered defenses rather than standalone efficacy.

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  40. https://www.washingtonpost.com/archive/politics/1996/06/05/japanese-ship-downs-us-plane/ba2bbbc4-5b2f-4b07-b1d2-cfc6a003e1b0/
  41. https://www.navylookout.com/last-ditch-defence-the-phalanx-close-in-weapon-system-in-focus/
  42. https://www.researchgate.net/publication/296444046_Analysis_on_effectiveness_of_phalanx_weapon_intercepting_hypersonic_missile
  43. https://navy-matters.blogspot.com/2014/11/ciws-assessment.html
  44. https://www.rand.org/content/dam/rand/pubs/papers/2013/P7515.pdf
  45. https://www.unmannedairspace.info/counter-uas-systems-and-policies/ukraine-requests-centurion-c-ram-from-the-us-would-it-be-enough-to-counter-drones/
  46. https://www.linkedin.com/pulse/c-ram-apoorv-srivastava-txwhc
  47. https://www.reddit.com/r/CombatFootage/comments/191iae9/cram_system_engaging_and_destroying_an_incoming/
  48. https://www.reddit.com/r/MilitaryPorn/comments/2ifjms/centurion_counterrocket_artillery_and_mortar_cram/
  49. https://milmag.pl/en/rtx-secures-contract-for-centurion-c-ram-support/
  50. https://www.globalsecurity.org/military/systems/ground/cram.htm
  51. https://missiledefenseadvocacy.org/defense-systems/counter-rocket-artillery-mortar-c-ram/
  52. https://www.twz.com/36412/centurions-roaring-whips-of-exploding-shells-are-still-engaging-rockets-over-iraqs-green-zone
  53. https://navy-matters.blogspot.com/2021/09/c-ram-performance.html
  54. https://www.reddit.com/r/CredibleDefense/comments/86o251/how_effective_is_the_centurion_cram_at_negating/
  55. https://interestingengineering.com/innovation/the-us-armys-c-ram-shot-down-suicide-drones-to-prevent-an-attack
  56. https://www.naval-technology.com/news/raytheon-us-navy-phalanx-ciws/
  57. https://harpgamer.com/harpforum/topic/30991-did-phalanx-ciws-the-last-defense-on-ship-and-ashore/
  58. https://www.naval-technology.com/news/rans-supply-phalanx-ciws-firing/
  59. https://thedefensewatch.com/product/phalanx-ciws-system/
  60. https://defensemirror.com/news/22078/Japan_to_Acquire_Phalanx_Close_in_Weapon_System_for_Naval_Defence
  61. https://www.navalnews.com/naval-news/2025/03/japans-asev-super-destroyer-fresh-details-unveiled/
  62. https://www.navalnews.com/naval-news/2020/12/united-states-approves-possible-fms-of-phalanx-ciws-for-koreas-kdx-iii-batch-ii/
  63. https://www.janes.com/osint-insights/defence-news/c4isr/south-korea-submits-procurement-requests-for-two-phalanx-ciws-units
  64. https://www.facebook.com/61555408054939/posts/naval-close-in-weapon-systems-ciws-from-around-the-world-protecting-ships-from-i/122210310032180268/
  65. https://www.gd-ots.com/wp-content/uploads/2017/11/goalkeeper.pdf
  66. https://missiledefenseadvocacy.org/defense-systems/goalkeeper-close-in-weapons-system-ciws/
  67. http://www.navweaps.com/Weapons/WNRussian_30mm-54_ak-630.php
  68. https://www.deagel.com/Components/AK-630/a001892
  69. https://armyrecognition.com/military-products/navy/weapons-systems/close-in-weapon-system/kashtan
  70. https://www.facebook.com/NavyGeneralBoard/posts/its-been-a-while-since-i-have-received-a-question-that-i-had-to-really-dig-aroun/520680823795707/
  71. https://www.quora.com/What-is-the-accuracy-of-the-Phalanx-Close-in-weapon-System-CIWS-when-it-comes-to-defending-naval-ships-from-incoming-anti-ship-missiles
  72. https://www.youtube.com/watch?v=yUQseFSb6dE
  73. https://www.thetruthaboutguns.com/us-navy-phalanx-ciws-vs-small-boat/
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