Calculation of Normal Force of Rudder behind Propeller

Abstract

To tackle a serious problem in predicting the manoeuvrability of a large ship at the initial design stage, the author has attempted to investigate the normal force of a rudder located behind a propeller, and presents a suitable formula for the estimation of such a force. The formula is derived from the application of the propeller momentum theory and the lifting line theory for thin plate of finite span, and is in rather good agreement with some experimental results. The formula is useful to evaluate the effect of the induced velocity of the propeller and the propeller diameter upon the normal force of the rudder. Application of the formula to the design of a rudder is also presented.