In the first report, outline of the basic designing of the single point mooring systems (SPM) was explained. And it was pointed out that the dynamic stability analysis can be applied practically to the primary planning of SPMs. Slow oscillation or weather vane motion of a moored ship sometimes causes excessive mooring force and whether the oscillation occurs or not can be predicted by the dynamic stability analysis. But the maximum mooring force, which is necessary for estimating the capacity of mooring system, has to be predicted by the numerical simulation in the time domain or model test. In this report, taking FPSO (Floating Production, Storage and Offloading system) with a turret mooring system for example, results of numerical simulation of the motion and mooring force of the FPSO in combined external forces of wave, wind and current are presented along with the model test results, which is conducted for the varification of the simulation. Dynamic effect on the mooring line tension in deep water and results of extreme value analysis of the tension are also discussed.