OrthoSpar, a novel substructure concept for floating offshore wind turbines: Physical model tests under towing conditions

An important condition of any port-assembled floating offshore wind turbine concept is the de-ballasted transport stage. As hydrostatic and dynamic stability may vary greatly from operational condition, it needs to be carefully investigated in early stages design-phase. In this work, physical modelling OrthoSpar device was carried out determine roll pitch RAOs, as well load characteristics towing line. Towing simulated with a stationary model being subjected currents. To examine influence wave direction, range orientations towards incident waves were tested still water together state. Roll motions found highly dependent on frequency result low damping ratio. The amplitude influenced by direction regarding direction.