Switzerland-based equipment manufacturer Liebherr is set to unveil a new RL-K 7500 subsea crane with knuckle boom for the oil and gas industry, during customer days at the production plant in Rostock in January 2013.
With a maximum rope diameter of 100mm and a maximum overturning moment of 75,000 kNm, the new crane is believed to be able to lift about 260t in the air and handle loads down to a water depth of 3,400m.
The crane’s boom configuration can be increased for working radii of 50m on demand, while its knuckle boom allows load to be lowered to the water surface with a short rope length between crane boom head and water line.
It is also fitted with modern hydraulic, electric and electronic features and functions, which includes the active heave compensation (AHC) system.
AHC is based on advanced motion reference units (MRUs) and contains sensors that can automatically recognise and predict the vessel’s motion in all weather conditions without any requirement of manual adjustment.
Liebherr upgraded its hydraulic hybrid drive system Pactronic for subsea applications, so that it can provide about 70% of the power required to operate the AHC system.
The subsea crane is also equipped with a horizontal winch shifting system that is expected to ensure the correct fleet angle of the rope under all load conditions in both hoisting and lowering operations.
In addition, a vertical winch frame lifting system which includes two hydraulic cylinders is fitted with the crane, to adjust the lifting height without moving the drum of the hoisting winch.
The RL-K 7500 crane, which can hoist loads of up to 300t, can be installed onboard drill vessels and heavy lift vessels.
Liebherr also plans to equip the knuckle boom with an Arctic temperature package, on customer demand, that will enable the subsea crane to operate at -40°C temperatures.
Image: Liebherr will unveil the new RL-K 7500 subsea crane in January 2013. Photo courtesy of Leibherr.