Motion Compensation Systems



Transfer Lifts: A Transfer lift occurs when a certain payload is required to be lifted from a supply vessel onto another floating vessel (e.g. semi submersible platform) using a crane on the semi. In-Line Heave Compensators are used in this instance to reduce the dynamic load on cranes (due to vessel motion). They significantly reduce the possibility of re-contact with the load being lifted which, if allowed to occur, may represent a serious safety threat.

Splash Zone: The "Splash Zone" is the area immediatly above and below the mean water line. Utilizing an In-Line Heave Compensator in an offshore lift (equipment with large surface area) when going thru the splash zone significantly reduces the dynamic forces due to the direct interaction with the sea in addition to the usual forces encountered with moving vessels/platforms/cranes offshore.

Subsea Landing: Equipment anywhere below the wterline or "splash zone" would be sonsidered subsea work. Utilization of Sea Spring will result in reduced landing speeds for complex and / or large subsea structures on the sea floor or desired subsea structure. Sea Spring's stroke / de-stroke action will compensate the boom tip movements thereby limiting the subsea payload movements.

Subsea Retrieval: Subsea objects being retrieved from ocean floor may cause large dynamic forces in crane and wire rope because of the vessel movement due to heave action and suction forces generated at lift off. Sea Spring is an ideal tool to absorb the energy generated because of these forces. Passive Compensation characteristics of the Sea Spring allows the unit to work as a constant tensioning system, with extra dampening once the subsea object is set loose from the ocean floor.

Subsea Resonance Control: Wave and ocean movements have varying frequencies that can quickly amplify the forces involved if they should form some resonance with the equipment and/or crane. Adding a Sea Spring unit to the rigging system will increase the safety by shifting the system frequency to avoid any match with that of the wave induced frequencies.

Overload Protection: In-Line Heave Compensators provide a simple solution for the protection of you crane. By stabalizing forces acting on the crane any potential scenarios in which the load applied might momentarily be enough to compromise the crane a heave compensator helps improve safety and reliability against overloading.