Abstract: In a broad aspect, the invention relates to a new design for a fairlead that is capable of being remotely uninstalled from and then reinstalled on an offshore drilling and production vessel, while the vessel is in its moored position, in the event that the fairlead develops mechanical difficulties that require repair. Thus, the present invention discloses a fairlead that may be remotely uninstalled and reinstalled while the fairlead is underwater and without ballasting the vessel far enough to raise the fairlead above the water surface. The need for this invention primarily arises in connection with fairleads that are mounted to a vessel of the type where the ballasting process can be a very difficult, time-consuming, and expensive process.

Abstract: A mooring unit and method of retrofitting a mooring unit are provided. Certain existing combination mooring units, of the type having two wire rope drums and two wildcats, are experiencing increased winch drive train component stress levels during operation when used in water deeper than they were designed for. Existing units are modified by providing left and right twin drum traction winch assemblies and additional winches. The existing wire rope drums are discarded, or reused with the additional winches. The additional winches are preferably mounted below the mooring unit. The twin drum traction winch assemblies, which deliver a constant winch pull force, are vertically mounted within the support flanges where the removed wire rope drums were previously mounted, without any modification to the support flanges.

Abstract: A composite storage winch for use in the deployment and retrieval of anchor systems employed with motive offshore drilling platforms.

Abstract: A motion compensation system for a crane hoist serves to assist the crane operator in safely lifting loads from the deck of a heaving work boat. The crane hook follows the motion of the load because a level of pre-tension is maintained on the line by use of a counterweight connected to the reeving system. A hydraulic cylinder connected to the counterweight provides for locking movement of the counterweight and also provides a cushion at both ends of its travel. Movement of the piston in the cylinder is controlled by a system including a check valve controlling flow between opposite ends of the cylinder which permits the reeving system to take up line. A limit switch responds to movement of the piston and counterweight near the top of their travel to actuate a light to warn the operator of a need to pay out line. As the piston and counterweight approach the bottom of their travel which indicates the load is moving upward, another limit switch actuates a light to indicate time to lift the load.