FPSOs are typically constructed by installing oil and gas processing systems onto the deck of either an existing crude oil tanker vessels or a new build tanker hull. FPSOs are suitable for most offshore regions throughout the world. They are normally moored to the seabed through a spread mooring system, however when situated in areas with sever weather conditions they are moored by a turret mooring system which allows the vessel to freely rotate with ocean- and wind forces. The major advantages of FPSOs are cost efficiency in combination with high mobility, large storage capacity and production versatility.