Abstract: A low drag ship hull generally includes a side air cavity initiated by wetted bow section, bottom air cavity initiated by wetted bottom nosepiece, wetted stem section that closes a lower portion of the side cavity, wetted bottom tailpiece that closes the bottom cavity, stabilizing fin, and propulsor. The bottom of a catamaran hull cross structure includes bow impact alleviator. Optional flaps in the stabilizing fins, together with optional all-movable canard fins are used for control. Different wetted bow sections and retractable plates are used for starting side cavities. A low drag hull may utilize multiple air cavities. A new low drag hull includes a new upper bottom air cavity that is initiated by an upper bottom wetted nosepiece, and closed by an upper bottom tailpiece. Alternative designs include a shortened forward hull spaced ahead of a shortened aft hull, and a hydrofoil-supported trimaran with low drag hulls.

Abstract: The invention relates to the use of gas cavities to reduce frictional drag on underwater surfaces such as hydrofoils, struts, fins, rudders, keels, propeller blades, ship hulls, underwater bodies, and wetted surfaces in general. Each gas-filled cavity is formed behind a discontinuity in the surface that causes the water boundary layer to separate from the surface. Gas is ejected into a region behind the discontinuity to fill the cavity; the gas can be air. If a cavity is open to the atmosphere, then air can typically fill the cavity naturally without air ejection. Cavities can either be closed or open. A low drag hydrofoil may have a closed cavity on one side, and an open cavity on the other side. For closed cavities, the underlying surface can be shaped to minimize cavity closure drag. Various ways to generate cavities, change hydrodynamic forces, and duct gas internally on hydrofoils and struts with cavities are covered.

Abstract: The invention is gas-filled cavities that reduce drag on the underwater surfaces of marine vehicles. Hydrofoils, struts, boat and ship hulls, pontoons, underwater bodies, fins, rudders, fairings, protuberances, submarine sails and propulsors are underwater surfaces that may be covered by the gas-filled cavities to reduce drag on them. The gas-filled cavities are to be used on underwater surfaces of marine vehicles, such as hydrofoil craft, monohulls, catamarans, SWATH (small waterplane area twin hull) craft, SES (surface-effect ships) and WIG (wing-in-ground effect) vehicles. Each gas-filled cavity is formed by ejecting air near the end of each nosepiece. Air is ejected at a speed and direction which is close to that of the water at the local cavity wall. The cavity is formed behind the nosepiece. The nosepiece is adapted to control the shape of the cavity.

Abstract: The invention is gas-filled cavities that reduce drag on the underwater surfaces of marine vehicles. Hydrofoils, struts, boat and ship hulls, pontoons, underwater bodies, fins, rudders, fairings, protuberances, submarine sails and propulsors are underwater surfaces that may be covered by the gas-filled cavities to reduce drag on them. The gas-filled cavities are to be used on underwater surfaces of marine vehicles, such as hydrofoil craft, monohulls, catamarans, SWATH (small waterplane area twin hull) craft, SES (surface-effect ships) and WIG (wing-in-ground effect) vehicles. Each gas-filled cavity is formed by ejecting air near the end of each nosepiece. Air is ejected at a speed and direction which is close to that of the water at the local cavity wall. The cavity is formed behind the nosepiece. The nosepiece is adapted to control the shape of the cavity.

Abstract: In a catamaran boat, including a propulsion system, and main hull positioned to travel above the water surface, the hull extending longitudinally forwardly, the combination comprising: two pontoons, each spaced below the main hull, the pontoons extending forwardly; support means carried by the main hull and carrying the pontoons, whereby the pontoons are at least mostly submerged below the water surface when the boat is loaded and at rest; the pontoons having associated chines positioned to permit the pontoons to plane on the water surface at typical planing speeds of the boat; the support means having streamlined leading edge structure and upper sponson structure; and the support means having lateral thickness at a longitudinal location spaced at a level above the pontoons and which is less than the maximum width of each of the pontoons at the longitudinal location.

Abstract: A submarine drone has special hydrodynamic performance features for operag as a moving underwater platform for underwater transport of a barrel stave type sonar receiving transducer and a pole type sonar transmitting transducer with highly precise vertical alignment. The body of the submarine comprises a generally spherical pressure hull for containing propulsion plant and electronic components. The barrel stave transducer is affixed about the upper half of the pressure hull. An acoustically transparent false wall forms a spherical hydrodynamic wall over the pressure vessel and transducer. The false wall also forms a tail cone projecting from the rear side of the submarine. The tail cone contains an annular channel which takes in boundary layer water from the spherical portion of hydrodynamic wall and conducts it back to a pump jet at the extreme rear of the tail cone. A fixed tail boom emerges from the center of the pump jet structure and extends rearwardly.

Abstract: A semi-submerged ship which has twin, parallel submerged lower hulls spaced apart at least two hull widths, a strut structure extending upwardly from the hulls on each side of the ship, and a cross-structure connected between the upper regions of the strut structure to connect the opposite sides of the ship together. The strut structure on each side consists of at least two spaced lower struts extending upwardly from the hull on that side, and a single, full length upper strut attached to the upper ends of the lower struts, the upper struts lying above the design water line at rest.

Abstract: A catamaran vessel comprises a pair of spaced, parallel elongated pontoons with a strut extending upwardly from each of the pontoons and a superstructure supported on the struts for riding above the waterline. Each pontoon has a sharp chine at its inner and outer edges and is of varying cross-sectional width along at least part of its height, with the widest point in the cross-section being situated below the upper surface of the pontoon. The lower surface of each pontoon comprises a planing surface on which the vessel planes at speed.

Abstract: A semi-submerged ship having a superstructure supported on struts above a pair of submerged buoyant hulls, the structure being arranged in such a manner that cargo can be stored in or passed through the struts and submerged hulls. Internal structure is minimized by using double walled load bearing construction, with easy access through the struts between the superstructure and the submerged hulls. The arrangement is adaptable to solid or liquid cargo, with provision for circulating liquid and for thermal control when required. The structure can be applied to a wide range of design configurations to suit various size, performance, function and payload requirements.

Abstract: A low drag underwater vehicle utilizing boundary layer suction is provided herein the vehicle includes a hull having nose, mid and tail sections. A permeable shell is mounted in a spaced relationship about the hull so that ambient water can be drawn into the space therebetween. The space between the permeable shell and the hull is divided into nose, mid and tail compartments. A pump is provided. Separate passageways are provided for connecting the nose and tail compartments to the pump and for connecting the mid compartment to the pump. The pump is capable of pumping the nose and tail compartments at a greater rate per unit area of permeable shell than the mid compartment. With this arrangement boundary layer suction through the permeable shell is greater at the nose and tail portions of the underwater vehicle than at the mid portion where the tendency toward turbulence is not as severe.

Abstract: Two groups of tension lines depending from the forward and aft portions of n airship are each connected to a separate vertically oriented elongate strut. The struts are dimensioned to extend through and below surface waves of a body of water. Optionally, electric thruster/generator units are mounted in pods on the bottom of the struts to either propel the airship or act as generators while drifting. Laterally reaching hydrofoils extend from the pods and either work to reduce drag or ensure responsive operation. The combination of the tension lines, struts, thruster/generator units and hydrofoils permits precise maneuvering at the surface for off-loading and on-loading at sea, allows for long endurance and range and gives a capability for operating as a quiet platform.

Abstract: A catamaran vessel comprises a pair of spaced, parallel elongated pontoons with a strut extending upwardly from each of the pontoons and a superstructure supported on the struts for riding above the waterline. Each pontoon has a sharp chine at its inner and outer edges and is of varying cross-sectional width along at least part of its height, with the widest point in the cross-section being situated below the upper surface of the pontoon. The lower surface of each pontoon comprises a planing surface on which the vessel planes at speed.