Thirty-six years from combat failure to redemption in the Red Sea
The Phalanx Close-In Weapon System (CIWS), pronounced “SEE-wiz,” has served as the U.S. Navy’s last line of defense against anti-ship missiles, aircraft, and other fast-moving threats. Equipped with a six-barreled 20mm cannon capable of firing over 4,500 rounds per minute, the system can autonomously search, detect, track, and engage incoming projectiles at close range. The Phalanx has been installed on all U.S. Navy surface combatants and those of 24 allied nations, yet for decades, it had never proven itself in actual combat—until recently.
Operation Praying Mantis: A System Put to the Test
The first combat test came during Operation Praying Mantis on April 18, 1988, the largest U.S. Navy surface action since World War II. Responding to mine strikes by the Iranian frigate Sabalan, the U.S. Navy engaged Iranian platforms and patrol boats in the Arabian Gulf. The operation marked the first and only time the U.S. Navy exchanged surface-to-surface missile fire with an enemy.
When the Iranian Kamen-class missile patrol boat Joshan detected the U.S. Surface Action Group Charlie—consisting of USS Wainwright, USS Simpson, and USS Bagley—it locked on with fire-control radar. Despite repeated warnings from Captain Chandler aboard the Wainwright, the Joshan launched its final operational Harpoon anti-ship missile at close range. The USS Wainwright was fitted with a Mk 15 Block 0 Phalanx CIWS in full automatic mode, yet the system failed to engage the incoming threat.
The missile passed dangerously close down the Wainwright’s starboard side, missing narrowly due to a combination of factors. Post-action investigation revealed a critical problem: the CIWS firing cut-out cams—safety limiters designed to prevent the system from shooting up its own ship—had been incorrectly configured by a previous commanding officer who feared damaging forward antennas. The engineers designing those limits understood their purpose; the settings were quickly corrected. Additionally, Captain Chandler’s tactical decision to present the ship’s minimal radar cross-section and steer through the chaff cloud likely aided the evasion. In response to the Harpoon launch, the Simpson and Wainwright fired Standard missiles that struck the Joshan’s superstructure, severely damaging the Iranian vessel.
USS Gravely: Redemption in the Red Sea
Decades later, the Phalanx would finally demonstrate its intended capability. On January 30, 2024, the Arleigh Burke-class guided-missile destroyer USS Gravely (DDG-107), part of the Dwight D. Eisenhower Carrier Strike Group deployed to the Middle East, faced an attack from Houthi rebels operating in the Red Sea. A Houthi cruise missile came within one nautical mile of the ship—closer than any previous attack on a U.S. warship in the region, according to CNN.
Previous Houthi attacks had been intercepted at distances of eight miles or more, but improved tactics or positioning allowed this missile to penetrate the outer defense layers. When the threat reached close range, the Gravely’s Phalanx CIWS engaged automatically and destroyed the incoming projectile—marking the first time the defensive system saw combat action on a warship.
Tom Karako of the Center for Strategic and International Studies’ Missile Defense Project characterized the incident as concerning, noting that even at subsonic speeds, a missile covering one mile could reach its target within seconds. He emphasized that Houthi weapons technology originated from Iran and highlighted a growing challenge: the “capacity problem” of finite interceptor missile supplies aboard U.S. warships. As Karako stated, “We can’t afford to sit here and play catch indefinitely.”
The 2024 incident underscored both the evolution of threats in contested waters and the critical importance of properly configured and maintained air-defense systems—lessons hard-won during Operation Praying Mantis thirty-six years earlier.
Photo by Jim Laurier, PH2 Michael A. Harnar, CWO2 Kenneth H. Brewer / U.S. Navy and Paraxade via Wikipedia
