OPV (Offshore Patrol Vessel)

A constabulary patrol ship, typically 60 to 90 meters and 1,500 to 2,500 tonnes, for sustained presence in the exclusive economic zone (UNCLOS Article 56, to 200 nm): fisheries enforcement, anti-smuggling, pollution response, and search and rescue. OPVs carry a helicopter or boats, a medium gun, and long endurance but limited combat systems, trading warfighting capability for low cost and sea time. They bridge the gap between small coastal patrol boats and frigates, and are operated by both coast guards and navies.