Abstract: A sailboat which uses hydrofoils either immersed or planning on the water's surface to resist heeling. The boat uses two hydrofoil assemblies, one for the starboard side of the boat and one for its port side. Each part can generate either positive or negative lift. The attack angles and depths of immersion of each hydrofoil are adjustable. The struts which hold the hydrofoils are designed so that the leeway forces produced by the struts are much lower than the lifts produced by the hydrofoils so there is little or no conflict between the hydrodynamic force produced by the hydrofoil and its supporting strut.

Abstract: An apparatus for a sailboat which can be used to oppose heeling caused by the wind on the sail. The apparatus includes hydrofoils which are substantially aligned with the leeway angle. In one embodiment, the hydrofoils can be withdrawn from holders and re-inserted or shifted in position when the boat tacks and the wind comes from the other side. In another embodiment, the hydrofoils can automatically assume a position substantially parallel to the leeway angle when the boat is sailing.

Abstract: A method of scanning a laser beam in a straight line is disclosed wherein a series of different frequency overlapping signals are applied to a first axis transducer of an acousto-optic modulator and a slowly varying frequency signal is applied to a second axis transducer of the acousto-optic modulator to generate a parallelogram matrix scan of a format converter which converts the scan to a linear scan focused in an image plane.