Abstract: A mooring system for a Floating Production, Storage and Offloading vessel (FPSO) employs a vessel mounted rotatable turret and a single point mooring arrangement. The mooring arrangement includes a single anchor chain that is removably attached at a top end to the vessel, and is attached at a submerged bottom end to three sealed anchored leg chains. The anchor chain is secured to the vessel by means of a chain stopper that is centrally located in the rotatable turret, and allows the vessel to rotate freely about the anchor chain's vertical axis. One or more submerged fluid carrying risers are detachably connected to a swivel stack positioned above the mooring table in line with the rotational axis of the anchor chain so that the risers and the anchor chain will not become entangled with one another during vessel rotation.

Abstract: A mooring system employs a vessel mounted turret in combination with a submerged chain table that also acts as a clump weight. The chain table is submerged fairly close to the sea surface at approximately the keel depth of the vessel, or a few meters below that depth. Three or more chains connect the vessel mounted turret and chain table to one another, preferably though corresponding U-joints. Several mooring lines are attached at first ends to the bottom of the chain table, and are secured at second ends to anchors or piles in the seabed. The weight of the chain table is chosen so that it helps reduce the stresses imparted by the vessel to the mooring lines, thereby reducing the maximum load requirement, and thus cost, of the mooring lines.