Patent ID: 8613322

Claim:
A method for motion compensation while conducting intervention operations on a subsea installation from a floating vessel comprising: a. mounting a motion compensation apparatus on said floating vessel, wherein said motion compensation apparatus comprises: i. a first support frame having an opening; ii. a second support frame disposed within said opening of said first frame; iii. at least one lifting cylinder having a first end and a second end, wherein the first end of said at least one lifting cylinder is connected to said first support frame, said second end of said at least one lifting cylinder is connected to said second support frame; and iv. a monitoring control assembly comprising: aa. at least one electronic sensor adapted to measure support frame tension, speed or position data; and bb. at least one processor; b. running an intervention means from said floating vessel through said motion compensation apparatus to said subsea installation; and c. controlling said at least one lifting cylinder based on data measured by said at least one electronic sensor to adjust the vertical position of said second support frame relative to said first support frame to maintain a substantially constant vertical distance between said second support frame and said subsea installation.