I believe it works because the sail consists of negative mass. The overall mass of the boat is therefore lower, but the part of the hull that's under water produces the same amount of bouyancy based on the area of displaced water. Because of the width of the hull, it's a stable equallibrium.
Interestingly, if the sail were to become submerged, it would create negative bouyancy and the boat would sink!
I believe it works because the sail consists of negative mass. The overall mass of the boat is therefore lower, but the part of the hull that's under water produces the same amount of bouyancy based on the area of displaced water. Because of the width of the hull, it's a stable equallibrium.
Interestingly, if the sail were to become submerged, it would create negative bouyancy and the boat would sink!