MOTION COMPENSATION: CMC-1 CABLE MOTION COMPENSATOR

The CMC-1 Cable Motion Compensator provides both depth and motion compensation for packages landed subsea. It works with wire rope, synthetic rope, or any steel tubular member.  By varying cylinder size, it compensates any load which will be lowered.

Fitting between the deploying cable and the landing package, it works with any vessel or winch, including synthetic rope winches.  The vessels and/or winches do not need to have their own motion compensation methods.

To the right/below the Cable Motion Compensator is shown in the Neutral Position, Vessel Down, and Vessel Up positions.  Note the piston rod and hook stay at the same elevation.  The cylinder moves up and down as the vessel goes up and down.   The piston has the same size rod on each end exposed to the environment.  It is automatically pressure compensated as the ocean water depth increases.

To the left/above the landing package is just below the surface in the ocean water.  It is now at its buoyed weight.  Increase the nitrogen pressure in the CMC-1 Cable Motion Compensator to bring the cylinder up to the neutral position. It will be in full heave compensation mode now.  So, judge that the movements above and below the neutral position are approximately equal.

To the right/below the landing package to be landed is nearing its landing position.  Due to the pressure balancing of the piston rods, the motion compensation here will be the same as it was near the surface.  Once it has landed, an ROV releases the hook and recovers the Cable Motion Compensator with the cable.

Patent Pending