A reference book for anyone wishing to understand the factors governing the performance of a sailing boat. Examined here are the fundamental factors governing a hull's behaviour, the principles underlying aero- and hydrodynamics, the performance and efficiency of aerofoils and hydrofoils, and an in-depth study of the behaviour of sails. The appendices take an in-depth look at high speed sailing and examine developments in hull appendages.A new appendix in this edition presents a simple graphic method of predicting a yacht's behaviour in a variety of wind and wave conditions which will add to our knowledge of how important such factors as sail camber, stability and the reduction of hull resistance are to a yacht's speed performance. Professor Marchaj is also the author of Sail Performance and Seaworthiness, the Forgotten Factor.