The Huisman Monopile Gripper has been designed to be light and compact while maintaining a high level of stiffness. Extensive dynamic analysis has shown that the stiffness of the gripper is one of the most important design characteristics for controlling and mitigating unwanted monopile oscillations. High stiffness results in less deflection and more control over the monopile, extending the operating window.
The gripper ring interfaces with the monopile via a set of roller boxes and forms the interface between the pile and the vessel. In addition to the main roller boxes, three additional rollers are provided to rotate the monopile. Two large doors provide an opening to bring the monopile into the ring and allow the gripper to retract while the monopile is in the ring. A hydraulically operated locking mechanism ensures that the gripper remains closed during operation. All major functions on the ring are hydraulically controlled.
The verticality of the monopile is controlled by moving the gripper in X and Y directions. By changing the position of the ring with respect to the vessel the monopile position and its angle with respect to the vertical can be accurately controlled.
The pile gripper can be controlled from a WAB or from a fixed control location.