Hydrodynamic Analysis on Sailing : 1st Report

Abstract

Sailing is very old yet a highly gallant way of ship propulsion. This paper represents a scientific analysis on it. The procedure is: to predict hydrodynamic force and moment acting upon a ship's hull from model tank test, taking account of leeway, heel and counter rudder deflection; to predict aerodynamic force acting upon sails from model sail experiment; then putting these data into the equation of equilibrium, we obtain ship speed, angle of leeway, angle of heel and rudder deflection for a given wind velocity and direction. Trial study on a 7.8 metre cruising sloop proved to be a satisfactory result on the whole. Such study will hopefully provide a useful help to yacht designers by, e.g., telling him an optimum amount of "lead" (distance between C.E. and C.L.R.) of a given design.