強風下の操船性能について

抄録

Conventionally, the upper limit of wind velocity at which a ship is manoeuvrable is estimated by solving equilibrium equations of steady motion of a ship. However, this method is not realistic because the actual steered motion of a ship in wind is unsteady. In this report, the authors investigate the manoeuvrability of a ship in wind not only by solving non-linear equations of motion numerically on a digital computer, but also by carrying out a steering test with a manoeuvring simulator. From this investigation, a more realistic upper limit of wind velocity is obtained. And by comparison of this value with the one estimated by equilibrium equations, the relation is made clear that, in the beam and quarter wind severest in ship manoeuvring, the realistic upper limit of wind velocity obtained as above is nearly equal to the one estimated by the equilibrium equations of steady motion of a ship whose rudder angle is kept at 15 degrees. By using this relation, the upper limit of wind velocity for many kinds of ships are shown in Fig.24. Moreover, this report describes effects of shallow water, rudder area, waves, uniform current and fluctuated wind on the upper limit of wind velocity.