Bosch Rexroth solves problem of safe crane operation at sea
24/11/2011 Bosch Rexroth Ltd
Dutch company Barge Master BV, installed Rexroth heave compensation to enhance the effectiveness of offshore cranes.Wind farms and drilling platforms are becoming more widespread, with construction costs playing an integral role in their development. In previous years, the lack of convincing crane technology has proven to be a big problem.
"Right now, standard floating cranes encounter difficulty with waves cresting at thirty centimetres. Safe crane operation can no longer be guaranteed" says Jan-Paul van der Bos from Barge Master BV. Even minor swaying of just two to three degrees can move the tip of the crane by four to five metres. This results in an unstable load and puts the crew at risk. Barge Master wanted to solve this problem.
By working with Bosch Rexroth, Barge Master developed a comprehensive solution including all the necessary drive and control components. The resulting system is suitable for all kinds of standard marine vessels and cranes. It drastically reduces the manufacturing cost and operational expense of offshore projects.
The Rexroth system also delivers in terms of technology. "With Rexroth heave compensation we have expanded the application window for floating cranes handling waves of up to 150 centimetres" adds van den Bos. This is achieved through a moving platform which neutralises roll, yaw and heave. Three hydraulic cylinders, affixed vertically, attach the crane to the hull of the ship through joints that incorporate ball bearings. Connection rods with limited mobility freeze the remaining three degrees of freedom so that the cylinder movements can compensate for wave action.
The controls are the heart of the solution. Special sensors deliver motion data which is used to calculate target values for the compensatory movements that keep the platform stable. Even with irregular swells and crests of over a metre, 95% of motion can be neutralised. Barge Master has therefore been able to expand the use range for standard floating cranes.
It is predicted that by mid-2012 the C400 Barge Master will be ready for use with cranes weighing about 400 tons with payloads of up to 160 tons. Barge Master is confident that this will significantly expand the utility of standard cranes in the sector.
Further information on Bosch Rexroth can be found at www.boschrexroth.co.uk
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