As operations in deep waters are becoming increasingly important, Cranemaster continues to invest in units equipped with depth compensation systems. For standard units, the hydrostatic pressure on the piston rod will reduce the subsea stroke, and non-optimal settings are therefore normally required. With a depth compensated system, stroke will remain constant independent of depth.
Two different principles may be used to compensate for the depth. The first principle is based on releasing pressure in the active accumulators, typically controlled by valves and sensors. The other principle is based on a mechanical compensation, where one or more pistons having the same area as the main piston are balancing the force. A combination of the two principles are also used. The pressure release system aditionally compensates for temperature variations and changes in buoyancy, while the mechanical system excels in its simplicity and ability to compensate for ultra deep water.
Cranemaster offers systems with all depth compensation options. The mechanical depth compensation system is covered by US patent 7934561 “Depth Compensated Subsea Passive Heave Compensator”. InterMoore Inc, the owner of the patent, has granted an exclusive worldwide right for the use of the patent to Cranemaster.