OVERVIEW: The Mk 33 RBOC (Rapid Bloom Offboard Countermeasures) is a 112 mm ship-deployed decoy launcher introduced in the early 1970s. It launches chaff or infrared flares to protect naval vessels from radar- or IR-guided missiles.

DETAILS: The Mk 33 consists of four Mk 135 fixed-angle mortar launchers, each with six tubes arranged in elevations of 55°, 65°, and 75°. It was the U.S. Navy’s first generation of RBOC systems, designed to launch fast-blooming decoys using electromagnetic induction firing circuits, providing 75 m/s launch speed. Though eventually superseded by the Mk 36 SRBOC in the late 1970s, the Mk 33 remained in service on select ships through the 1980s.

FONCTION:
Activated via EW detection against radar/IR threats.
Fires flare rounds from fixed-angle 112 mm tubes.
Creates radar clouds to confuse incoming missiles.

SOURCE:
Military Periscope – “Mk 33 RBOC overview”; SecretProjects discussion on US RBOC systems; SimplePlanes technical summary of Mk 33 RBOC design and munitions.