Pacific Ocean (Nov. 27, 2006) – The amphibious assault ship USS Bonhomme Richard (LHD 6) performs a pre-action aim calibration on one of two MK-15 Phalanx Close-In Weapons Systems (CIWS). The basis of the system is a 20 mm M61 Vulcan gatling gun linked to a radar system for acquiring and tracking targets. The gun fires at a variable 4,500 rounds per minute (hydraulic models only fired 3,000 rounds per minute): it is mounted in a self-contained turret along with an automated fire control system. The system automatically searches, detects, tracks, engages and confirms kills using its computer-controlled radar system.