Abstract: Methods and devices for generating gas bubbles including a microbubble generating cell having a microporous mat permeable to gas appied thereagainst under pressure which has a ultrasonic energy generator such as a piezoelectric transducer in wave energy communication therewith for promoting flow and impeding fouling thereof. Such mat is comprised of compressed corrosion-resistant metal fibers of a diameter of between 2 and 80 microns, has a density of less than 70% of the density of the fibers and an average pore diameter of between 5 and 100 microns. Such methods and devices are associated with a vessel and/or a foil for a vessel for generating and dispensing microbubbles along the hull surfaces to reduce friction and turbulence on the wetted surface. The foil is positioned forward of vessel bowpeak with its trailing edge confronting same and has a microbubble dispenser for dispensing microbubbles in the path of the hull of the vessel.

Abstract: Vessels with improved performance capability and methods for improving such performance and foils which may be associated with a vessel for providing this improved performance capability. Additionally, a method and device for improving flow through a microporous barrier and a diffuser cell for generating gas bubbles, both of which may be associated with a vessel and/or a foil for a vessel for improving its performance. The foil is positioned forward of the vessel bowpeak with its trailing edge confronting same to impart momentum to water in the outboard direction to each side of the bowpeak while maintaining a streamline water flow, thereby reducing friction and turbulence on the wetted surface of the bow. The foil may have means of heating the surface of the leading section to reduce friction. The foil may have generators of and dispensers for friction reducing agents such as gas bubbles to distribute such agents into the path of the bow, advantageously from the trailing section of the foil.

Abstract: Planing vessels of improved performance capability and methods for improving such performance and foils which may be associated with a planing vessels for providing improved performance capability. A dynamic downward force generated as the vessel (1) moves through water, preferably by a foil (3), is imposed on the vessel, with the locus of the force positioned, in the traverse direction, at the longitudinal vertical centerline plane of the vessel. In the longitudinal direction the locus of the dynamic force is positioned, relative to the other forces acting fore-to-aft on the vessel, to decrease the trim angle of the vessel, desirably to less than two degrees. Vessel wetted surface configurations are provided for stable and efficient operation at low trim angles, including the following. A deep draft, fine entrance (32) which minimizes rise at the bow experienced with conventional planing vessels and assists in maintaining laminarity of flow at the planing surfaces.