Importance

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Abstract

A vessel with a rotatable turret thereon is moored in a manner that minimizes turret tilt while avoiding the need to maintain precisely concentric upper and lower turret bearings. A mooring structure (152, FIG. 7) is formed by a group of mooring lines (162, 164) such as chains, with the upper ends of the lines coupled to the vessel through a connecting apparatus (154) that comprises a group of arms (166) each connected to a corresponding one of the lines. Each arm is pivotally mounted (at 170) on the turret to hang therefrom, so the arm transmits primarily vertical forces to the turret and the turret bearing (185) has to support primarily vertical forces. Each arm carries a bearing pad (174) that presses horizontally against a vessel lower bearing ring (182) mounted directly on the vessel hull independently of the turret. Substantially the entire horizontal components H of mooring force are transmitted from the arm pads to the lower vessel bearing ring, so the horizontal force components are not transmitted through the turret. As a result, the turret does not tend to tilt, and the vessel lower bearing ring which transmits horizontal mooring force components does not have to be mounted precisely concentric with the upper bearing.

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First Claim