The USCG C51SC (United States Coast Guard) refers to a specific class of 123-foot Island-class patrol boats operated by the United States Coast Guard. These vessels are primarily used for law enforcement, search and rescue, and homeland security missions within coastal waters and rivers. They feature advanced capabilities such as high-speed propulsion, an aircraft facility for helicopter operations, and a modular design that allows for quick reconfiguration to accommodate various mission requirements. The C51SCs entered service in 2008, augmenting the Coast Guard’s fleet of medium endurance cutters.