Horizontally disposed hydrofoil system for monohull sailboat

摘要

A monohull sailing boat with a mast and sail is provided with a lifting hydrofoil 104 for each tack that can be moved from a stowed position to a deployed position projecting from the more immersed side of the boat and lying in and approximately parallel to the waterplane when the boat is at its normal optimal heeling angle 120. The deployed foil has an angle of attack of 2 to 6 degrees and provides a righting moment 122 counteracting the heeling moment of the boat as the foil moves through the water. The foil has an exposed aspect ratio of at least 2 and the exposed span of the foil is at least 7% of the mast height of the boat. Several embodiments of deployment mechanisms are disclosed.