It is now under consideration to moor ships to single-point mooring systems in a harbor while the weather is very severe. In this report, the analysis is made for the slow motions of ships moored to a SALM type buoy by numerical simulations and by hydraulic model tests at the laboratory. The study has yielded the following conclusions:
(1) In order to numerically simulate the slow motions in steady wind, it is very important to select proper values of the direction of wind forces, the drag force coefficient and the yaw moment coefficient.
(2) The mooring forces of a ship in wind are proportional to the square of wind velocity.
(3) The relationship of load displacement of buoy/bow-hawser arrangement can be calculated by considering the nonlinear elasticity of hawser, the hydrostatic restoring forces upon the buoy and the mooring forces of chains.
(4) Maximum mooring line loads for wind and waves occur when the wind direction is the same as that of waves.
(5) The slow motions of a ship are influenced by external currents. Further investigations are necessary to clarify the total effects of winds, waves and currents.