Abstract: A very large diameter turret for mooring a VLCC class FPSO vessel. A large diameter rail and wheel bearing system is disposed between a turret main deck and the hull of the vessel. The turret is designed for a flexibility to allow the turret main deck to conform to the sag or hog of the vessel so that excessive forces on the wheels of the bearing system are avoided. The turret's main deck, in a preferred embodiment, includes a center hub, an outer ring, and spokes between the hub and outer ring. A lower chain deck is preferably connected to the main deck by pillars or columns, or alternatively by riser tubes alone, or other structures that achieve the desired flexibility of the main deck.

Abstract: A method for constructing and installing a very large turret in a vessel without lifting the entire turret from a fabrication yard into the moonpool. According to a first alternative method, both the lower part and the upper part of the turret are constructed inside the moonpool while the vessel is in drydock. Such method obviates providing very large lifting cranes capable of lifting the entire turret including the upper part of the turret and the lower part into the moonpool. According to a second alternative embodiment, the turret has an upper part and a lower part and the lower part is constructed in the moonpool while the vessel is in drydock, like in the first alternative method. In the second embodiment, the lower part is supported by rods and jacks from the moonpool, and the vessel is floated out of drydock into the water and parked at dockside.

Abstract: A radial bearing assembly for a turret mooring system. The radial bearing has a radial clearance sufficient to allow the turret to have minor deflection without bearing contact against the turret's sliding surface. As a result, sliding wear on the lower bearing is reduced, and the upper bearing is allowed to rotate without incurring unnecessary bending moments caused by unavoidable structural tolerances in misalignment of the lower bearing with respect to the upper bearing's axis of rotation. In a storm environment, the lower bearing is capable of radially supporting the turret while allowing relative rotation of the vessel around the geostationary turret when larger mooring loads occur on the turret. A mounting arrangement for pads on radial bearing assemblies and the radial clearance allow replacement of the bearing elements while the vessel is moored by the turret in offshore waters.

Abstract: An arrangement and pull-in method for fluidly coupling a steel riser to a flowline of a turret on a FSO/FPSO. The riser is pulled into a connector by a pull-in line inside the flowline. A pull-in head is releasable secured inside the upper end of the riser. The pull-in head is released from the riser after the riser is locked into the connector. A flex joint is placed above the connector to provide alignment of the connector to the riser during installation.

Abstract: A method for constructing and installing a very large turret in a vessel without lifting the entire turret from a fabrication yard into the moonpool. According to a first alternative method, both the lower part and the upper part of the turret are constructed inside the moonpool while the vessel is in drydock. Such method obviates providing very large lifting cranes capable of lifting the entire turret including the upper part of the turret and the lower part into the moonpool. According to a second alternative embodiment, the turret has an upper part and a lower part and the lower part is constructed in the moonpool while the vessel is in drydock, like in the first alternative method. In the second embodiment, the lower part is supported by rods and jacks from the moonpool, and the vessel is floated out of drydock into the water and parked at dockside.

Abstract: A very large diameter turret for mooring a VLCC class FPSO vessel. A large diameter rail and wheel bearing system is disposed between a turret main deck and the hull of the vessel. The turret is designed for a flexibility to allow the turret main deck to conform to the sag or hog of the vessel so that excessive forces on the wheels of the bearing system are avoided. The turret's main deck, in a preferred embodiment, includes a center hub, an outer ring, and spokes between the hub and outer ring. A lower chain deck is preferably connected to the main deck by pillars or columns, or alternatively by riser tubes alone, or other structures that achieve the desired flexibility of the main deck.

Abstract: An arrangement and pull-in method for fluidly coupling a steel riser to a flowline of a turret on a FSO/FPSO. The riser is pulled into a connector by a pull-in line inside the flowline. A pull-in head is releasable secured inside the upper end of the riser. The pull-in head is released from the riser after the riser is locked into the connector. A flex joint is placed above the connector to provide alignment of the connector to the riser during installation.