MacGregor, part of Cargotec, has introduced the 3D Motion Compensator (3DMC), a flexible retrofit device, which is designed to enhance the load-handling precision of an offshore crane even in challenging sea states.
"MacGregor's standard active heave-compensation (AHC), supplied through a crane's winch, compensates for a vessel's vertical movements. However, when very accurate load positioning is required, such as landing loads on small fixed platforms, the 3DMC is a fantastic new option," says Alexander Nürnberg, Senior Vice President, Technology and R&D, MacGregor.
The 3DMC can be fitted to the knuckle jib of a broad spectrum of new or existing MacGregor subsea/offshore cranes. It compensates for the roll, pitch and heave motions of the vessel to minimise any movement of the load in relation to a fixed point in space.
During operations that require a greater degree of precision than that available from the standard crane, such as transferring equipment to or from offshore wind turbine structures or any fixed platform, the operator can opt to use the 3DMC.
"MacGregor recognises that any investment must deliver distinct operational advantages, particularly in today's challenging economic climate," adds Dr Nürnberg. "The 3DMC retrofit option does exactly that. It allows a shipowner to expand the load-handling capabilities of a crane far beyond its original limitations.
"This means that the crane and therefore the vessel can be used for more assignments and owners will be able to bid on a wider range of contracts," says Gaute Sjusdal, Director of Advanced Offshore Solutions, Global Lifecycle Support at MacGregor.
The 3DMC has been designed for easy installation and makes use of the existing hydraulic power unit and control system of the crane. The 3DMC / crane interface is designed so that the unit can be swiftly mobilised to a crane with the relevant fittings. This allows flexibility within a fleet of vessels that can share one or several 3DMCs between them.
The 3DMC is fully incorporated into the crane's control system so that all operations are performed from the existing interfaces in the crane cabin. When not required, the 3DMC simply remains fixed to the side of the crane's knuckle jib allowing normal lifting operations using the main and whip winches.