Shockingly, there are some instances where the US Navy's Phalanx Close-In Weapons System's (CIWS) red hot wall of 20mm tungsten isn't enough to neutralize incoming threats—like against fast moving anti-ship cruise missiles. For times like those, America's Navy relies on the Phalanx's bigger, badder, rocket-propelled brother: the SeaRAM.
First deployed in the early 1990s, the SeaRAM is, essentially, a modified Phalanx system. As the US Navy's product page explains, "The SeaRAM CIWS is a complete combat weapon system that automatically detects, evaluates, tracks, engages, and performs kill assessment against ASM and high speed aircraft threats in an extended self defense battle space envelope around the ship.
It utilizes the same frame, occupies the same footprint, and draws the same amount of power as the Phalanx. However, rather than firing 20 mm rounds, the SeaRAM fires the RIM-116 Rolling Airframe Missile (RAM). These self-guided missiles are equipped with tri-band passive radio and active IR seekers as well as 25 pound frag warheads. They're designed to intercept ground, air, and sea-launched threats up to 5.6 miles out while moving at Mach 2. Each SeaRAM can hold up to 11 of these $998,000 missiles.
The SeaRAM Anti-Ship Missile Defense System is a spiral development of key attributes of the Phalanx Close-In Weapon System and the Rolling Airframe Missile (RAM) Guided Weapon System. SeaRAM is designed to extend the inner layer battlespace and enable the ship to effectively engage multiple high-performance, supersonic and subsonic threats.
An 11-missile RAM launcher assembly replaces Phalanx's 20 mm gun. SeaRAM combines RAM's superior accuracy, extended range and high maneuverability with the Phalanx Block 1B's high resolution search-and-track sensor systems and reliable quick-response capability.
"No one has monolithic navy sea battles on the open waters anymore," Rick McDonnell, Raytheon's program director for close-in defense solutions, said in a press release. "Now navies need smaller, more affordable ships to defend shorelines and navigate around conflict regions."
As such, the SeaRAM system has been installed on two of the navy's new fleet of littoral combat ships, the USS Independence and USS Coronado. [Raytheon 1, 2 - Wiki - US Navy ]