A new Method for the Prediction of the Side Force on Keel and Rudder of a Sailing Yacht based on the Results of the Delft Systematic Yacht Hull Series

Since the first introduction of an expression for the assessment of the side force production of a sailing yacht as function of leeway and heel, based on the results of the Delft Systematic Yacht Hull Series, in 1981, considerable changes in appendage layouts and planforms have taken place. The side force production as function of the leeway and heel played only a very limited role in the present VPP calculations and remained therefore for many years somewhat undervalued. The last years more attention has been paid to the subject in particular caused by the necessity to asses the yaw balance of (large) sailing yachts and the introduction of maneuvering models for yachts under sail. This report shows the developments and presents a new assessment model which yields far better results for a large variety of appendages. The results of this study are presented in the present paper.