Offshore Mast Crane

Our Offshore Mast Crane (OMC) is a compact design heavy lift crane using state-of-the-art technology and designed for the use on offshore construction vessels and semi-submersibles. Many of the Offshore Mast Cranes are suitable for ultra deepwater operations up to 5,000m water depth. They make use of a deepwater hoist system with a single line capacity up to 300mt. The deepwater hoist system consists of a traction winch and a storage winch and can also be equipped with an Active Heave Compensation System.

The crane consists of a steel mast with a rectangular footprint which can be easily welded to the bulkheads of the vessel structure. The rectangular footprint allows an installation of the crane directly on the stern of the vessel, achieving a large effective outreach. The mast is fitted with a rotating slew platform and mast head. The slew platform supports the main boom at the pivots. From the mast head the boom hoist tackle runs to the top of the boom and controls the radius of the different hoists. Slewing of the slew platform and boom is achieved by pinion drives mounted to the fixed mast and driving the lower slew bearing. The mast head follows the slew motion of the boom. The height of the mast provides a superior load curve compared to traditional cranes, especially on bigger radii. The load moment is carried by the mast and not by the slew bearings. The lower slew bearing is therefore no longer a critical construction item.

The main winches are normally installed inside the crane pedestal, also providing housing for the electrical room and elevating the boom pivot to the requested level. The larger OMC's are fully revolving and therefore equipped with a rotating winch column. When the crane is outfitted with a deepwater hoisting system the traction winch is either installed inside the crane or in the hull of the vessel. The heavy storage winch is normally installed on the tank top. For a completely controlled and inherently safe load transfer an Active Heave Compensation System can be installed.

Our OMC has a low own weight as the crane is built up from high tensile steel and doesn't require ballast weight. The omission of ballast weight and the crane's compact design reduce the tail swing providing more free deck space.

Today's OMC's are delivered with electric frequency controlled inverter drives. Electric driven cranes require fewer components and are more reliable than hydraulic driven cranes. Technology in electronics is constantly improving leading to state-of-the-art cranes. In general, also the redundancy level of an electric driven crane is higher than a hydraulic driven crane.

Features like load tuggers, block tuggers and sling hoists are common practice on the Huisman Offshore Mast Cranes. Additional features like a Super Fly Jib, vertical sea fastening of the boom and trolley hoists can be provided.