Heave, Roll And Pitch Damping of a Deepwater CALM Buoy With a Skirt

Abstract

The heave, roll and pitch damping of a CALM buoy contains linear contributions (wave radiation) and quadratic contributions (drag loads). The linear damping can be determined by diffraction-radiation calculations, but for the quadratic contributions model test data are required. In this paper a semi-empirical model is formulated for the calculation of the quadratic heave, pitch and roll damping. Forced oscillation tests were carried out using a CALM buoy model with several different skirts. Different oscillation amplitudes and frequencies were considered. From the test results added mass and damping coefficients were determined. These results were used to validate the semi-empirical model.