..., the yacht would be drifted. The yacht should advance with the leeway angle (heading angle of the yacht centerline) to give attack angle so that the keel and rudder could generate compensating side forces. Both side forces from sails and keel/rudder also act like a coupling moment to heel the ship. The yacht...

... merchant ship equipped with some large sails has been proposed from respect of the practical use at the early stage. This merchant sail assisted ship cruises with heel angle and leeway angle to obtain the thrust from wind and a small leeway angle to generate lateral force to cancel the component of sail...