Offshore Patrol Vessel (OPV)

An offshore patrol vessel (OPV) is a lightly armed ocean-capable patrol ship built to police a nation’s exclusive economic zone, enforce fisheries and customs law, and run search-and-rescue, sitting in capability between a coastal patrol boat and a frigate. Typical OPVs displace about 600 to 2,500 tons on 60 to 120 meters, make over 24 knots, and reach 3,000 to 10,000 nautical miles with endurance near 30 days, carrying a helicopter deck or boats but usually no anti-submarine suite. They cost far less to build and crew than a frigate, so smaller navies and coast guards use them for the constabulary work that frigates are too expensive to perform.