An analysis of mean wave drift forces of FPSO systems by higher-order boundary element method

Mean wave drift forces and moments are critical for FPSO systems in mooring, riser in-stallation and offloading. In this paper, higher-order boundary element method (HOBEM) is applied and symmetry is considered to calculate the second order hydrodynamic interactions of Schiehallion type FPSO in NorthSea of England. The surge, sway and yaw mean drift forces on FPSO are computed by near-field method based on direct pressure integration. Comparing to conventional method, current algorithm has high accuracy and can converge steadily even for high frequency waves. It is shown that in order to control FPSO safely under severe sea condition, the FPSO systems should change its weathervaning angle to head sea all the time.