The technological developments in sailing yacht design and construction over the past fifteen years are tremendous. As a result of these developments, the present methods for the velocity prediction of sailing yachts are less applicable to recent high performance yacht designs. The accuracy of the velocity prediction suffers from this in some extent. In order to improve the velocity prediction of contemporary yachts from a hydrodynamic perspective, a new bare hull upright trimmed resistance prediction for modern high performance yachts, to be used in velocity prediction programs, has been derived in this thesis.