Anyone who’s ever operated a crane at sea, or worked as a roustabout or deck crew, can attend to the fact that operating cranes in a seaway is challenging at best, or downright deadly at worst. To help mitigate the issue of vessel motions during crane operations, Barge Master BV, a Dutch company, has installed a motion compensation system developed by Rexroth to neutralize waves and enhance the usefulness and safety of offshore cranes.
Barge Master launched the BM – 001, its first operational motion compensation platform in December to provide stability and safety to offshore crane operations. The moving platform utilizes a drive and control system from Bosch Rexroth to neutralize the roll, pitch and heave caused by waves and considerably expands the uses for standard floating cranes.
“Right now, standard floating cranes encounter difficulty with waves cresting at 30 centimetres. Safe crane operation can no longer be guaranteed,” said Barge Master Director Jan-Paul van den Bos.
Working together with Rexroth, Barge Master developed a comprehensive solution including all the necessary drive and control components to compensate for movements in three degrees of freedom.
Special sensors deliver motion data to the system, which calculates how the platform must move to compensate for the action of the waves. Three degrees of freedom (heave, roll and pitch) are compensated by three hydraulic cylinders that attach the crane to the hull of the ship. By measuring the motions of the vessel, and controlling the motion of the actuators, the cylinders’ movements can compensate for the waves.
The remaining degrees of freedom (surge, sway and yaw) are compensated by dynamic positioning of the vessel or traditional mooring systems.
The launch of the Barge Master platform will allow for cranes weighing approximately 400 tons to operate in swells up to five times greater than allowed by current systems. “With Rexroth motion compensation we have expanded the application window for the floating cranes – handling waves of up to 150 centimetres,” van den Bos noted.
The Barge Master system is suitable for all kinds of standard marine vessels, significantly expanding the utility of standard cranes, and drastically reducing the manufacturing costs and operating expenses for offshore projects.