The growth of offshore wind turbines, paired with the sector’s ambitions is pushing offshore wind farms further out into the sea. Floating vessels are expected to play a major role in turbine installation, unhindered by depth limitations and offering increased crane capacity required for larger, heavier monopiles.

Floating vessel installation offers certain advantages. Increased workability is an example. A floating vessel has no requirement to jack up before performing installation. It can also offer increased payload capacity and support a heavier crane as weight is less of an issue.

There are, however, several associated challenges. Amongst these are the dynamics of the monopile. Vessel motions and wave forces can excite the monopile into oscillation. To address the issues, Huisman developed a Motion Compensated Pile Gripper, a solution that prevents the monopile from uncontrolled oscillation during lowering and piling and keeps it vertical by compensating the vessel motions in the horizontal plane. The gripper can also double as an upend tool to facilitate pile handling, thus saving on deck space.

The Motion Compensated Pile Gripper uses a gripper ring system suspended from an XY-frame to move horizontally. The gripper ring connects with the monopile and adjusts for the vessel’s up and down, side to side, and rotational movements.

The XY-frame, positioned on deck rails, helps the gripper ring system handle the vessel’s horizontal movements and drift. To ensure the gripper’s accuracy during turbine installation, the XY-frame is designed with low friction Linear Bearings developed by Huisman. This design is compact, easy to maintain, and long-lasting.

Safety is a top priority in the design of Huisman’s Motion Compensated Pile Grippers. The grippers have a high level of redundancy to prevent hazardous situations from a single point of failure. Additionally, they feature a monopile emergency release system for added safety during operations.