Heave compensation adds to crane’s capability
Barge Master BV has 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”, said 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.
By working with Bosch Rexroth, the company 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, and in turn, it drastically reduces the manufacturing cost and operational expense of offshore projects.
It 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 and Mr van den Bos added that the heave compensation has meant that Barge Master is able to expand the application window for floating cranes, as these are now able to handle waves of up to 150 centimetres.
It is predicted that by the middle of this year the C400 Barge Master will be ready for use with cranes weighing about 400 tons with payloads of up to 160 tons, a move which should significantly expand the utility of standard cranes in the sector.
Images for this article - click to enlarge
Unless otherwise stated, all images copyright © Mercator Media 2012. This does not exclude the owner's assertion of copyright over the material.
