Influences of Propeller and Rudder on Maneuvering Stability Derivatives (continued report)

In the previous report, a simplified procedure to predict maneuvering stability derivatives of a ship equipped with a propeller and rudder from those of the bare hull was suggested. In the present report, the author shows some experiment results of derivatives obtained by changing propeller loading in the so-called circular motion tests. And indicated is the fact that the above mentioned method is usefull also in predicting the effect of propeller loading on the derivatives in the former condition.It was already pointed out that influence of propeller force on derivatives was not negligibly small in comparison with that of rudder force. Here, assuming that a ship's hull can be replaced by a rectangular plate wing with low aspect ratio, normal force induced on the hull by the action of the propeller is evaluated by using the linear lifting surface theory. According to the results of numerical calculation, the author discusses the qualitative trends concerning the effect of propeller loading on the force produced on the hull.