The authors have made extensive investigations on the wind effects on the maneuverability of ships with large superstructure, such as LNGCs and PCCs, from both experimental and theoretical aspects. This paper, as the first report of the above mentioned investigations, presents the results of the experimental study with the wind force simulating device. Using a 5.0 meter long and self-propelled LNGC model, and utilizing the wind force simulating device on the model deck as shown in Fig. 1, extensive free-running model tests were carried out for two kinds of typical ship maneuvering motions in wind, namely the course keeping motion and the turning motion both under steady wind condition. In addition to the model tests mentioned above, simulation calculations were carried out with mathematical model for the ship maneuvering motions in wind as described in Appendix. The computed results show satisfactory agreement with the model test results for various wind conditions as shown in Figs. 615. Through the present study, the following conclusions are obtained. (1) The experimental approach with the wind force simulating device is one of the promising and useful ways for the evaluation of the ship maneuverability in wind. (2) The simulation calculation based on the mathematical model as proposed in the present paper can give fairly good prediction for the ship maneuvering motions in wind.