Abstract: A vessel is provided with a transition hull that hydroplanes the vessel on a water surface at a high speed and displaces the water surface at a low speed.

Abstract: A vessel (10) designed to operate efficiently as both a catamaran and air cushion vessel can travel at low speed (e.g. Froude number (Fn)=0-0.3) in a catamaran or displacement mode and at high speed (e.g. Froude numbers (Fn)=0.3 or more) in an air cushion or dynamically supported mode. The vessel (10) includes molded catamaran hulls (11, 12) with parabolic waterlines, a flexible, air cushion seal system (16, 17), surface piercing propellers (20) and a propulsion system (e.g. combined diesel and gas turbine). There are preferably auxiliary gas turbines for generating lift air pressure. Forward mounted independently stabilizing foils (30), can optionally facilitate ride stabilization and load compensation at high and low speeds. The foils also generate transverse roll forces to improve high speed maneuvering.

Abstract: The stern unit (1) provides the movement and the steering of the marine craft. The stern unit (1) comprises a casing (2), a shaft (3), a shaft housing (4), water lubricated bearings (5), propeller (6), rudder (7), a rudder-stand (8) and a hydraulic piston (10). The stern unit (1) contains a fish-back shaped casing (2) acting as a tunnel and a propeller (6) near the outlet of said casing (2). The propeller (6) is connected to the inboard engine mounted in the marine craft, in a straight line by means of the transmission mechanism, using a shaft (3) borne in the shaft housing (4) and water bearings (5) without using any spiders and balls. The rudders activated by means of a hydraulic piston takes place in front of the propeller enable the marine craft to be guided.

Abstract: An unventilated, stepped hydroplaning boat hull has at least one midship step. Two separated wetted planing surfaces are thereby established—a forward surface just forward of the step and an aft surface just forward of an aft edge of the hull. The angles of attack of each planing surface preferably lie in the range 2.0-6.5 degrees, and are preferably equal. The midship step is preferably located longitudinally in a range of 0.45 to 0.51 times the projected chine length of the hull, measured aftward from a forwardmost point of the chine.

Abstract: A water sports performance boat includes a hull having a sharpened angle keel for cutting into the water. Reverse chines are carried on port and starboard sides and extending from a forward portion of the hull to an aft portion for inducing a lifting of the bow at generally low boat speeds and for providing a stabilizing effect. Port and starboard spray pockets are located at the aft portion of the hull for reducing a side spray of water near the transom. Performance strakes are formed within the hull with each extending from an aft position rearwardly to the transom. An elliptical shaped dispersion tunnel formed along the keel within an aft most portion of the hull extends through the transom and provides a desirable wake shape.

Abstract: A marine vessel which uniquely combines tumblehome-like and trimaran-like attributes in an integrative form describing two underside channels comprises a medial major hull and a pair of lateral minor hulls. The port and starboard minor hulls, each generally describing an inverted triangular cross-section, have respective outside surfaces which slope in tumblehome fashion (downwardly outwardly). The major hull has port and starboard outside surfaces which can slope in any fashion, whether tumblehome or nontumblehome. The outside surfaces of the minor hulls are parallel to the vessel's centerline, whereas the outside surfaces of the major hull aftwardly slant toward the centerline.

Abstract: A water craft apparatus has an elongated hull with turbine propulsion drive adapted for ingesting water at a turbine water intake and for ejecting the water, with high velocity, at a turbine water outlet. A plurality of water suction apertures are arranged along both a starboard and a port portions of the hull, and these are in communication, through an intake manifold, with the turbine at the water intake for delivering the water from the body of water to the turbine. A plurality of aperture doors are hingably mounted on the hull, each one of the plurality of aperture doors is movable between an open attitude spaced outwardly from the one of the water suction apertures enabling admittance of the water into the intake manifold, and a closed attitude positioned for sealing the one of the water suction apertures. The apertures span a longitudinal distance along the hull. The longitudinal distance exceeds a horizontal length of a wave cycle of the body of water.

Abstract: The hull has two lateral hull portions (5a, 5b) spaced part with respect to each other which each extends from a respective lateral wall of a front hull portion (1) beyond the rear end (1a) of the front hull portion (1). Lateral hull portions (5a, 5) are directly connected to a respective lateral wall of front hull portion (1). A respective tunnel (15a, 15b), open downwardly, is formed between the front hull portion (1) and each lateral hull portion (5a, 5b). Tunnels (15a, 15b) run into a further tunnel (15) defined behind the rear end (1a) of the front hull portion (1), between the lateral hull portions (5a, 5b).

Abstract: A watercraft constructed according to the invention includes at least one hull according to the invention described in the grandparent and great-grandparent patent applications that issued as U.S. Pat. Nos. 6,314,903 and 6,250,245, which hull includes first and second channel defining structures connected to the hull that define a first channel on a port side of the hull with a forwardly facing first channel entrance and a second channel on a starboard side of the hull with a second forwardly facing channel entrance. According to one aspect of the invention, the hull has a bow that extends to a vertical knife edge, and the first and second wing channel entrances are arranged to form a near horizontal knife edge at the deck level in order to enhance high speed operations. According to another aspect of the invention, there is provided an onboard air system for injecting air into the first and second channels in order to enhance high speed operation of the watercraft.

Abstract: A watercraft constructed according to the invention includes at least one hull according to the invention described in the grandparent and great-grandparent patent applications that issued as U.S. Pat. Nos. 6,314,903 and 6,250,245, which hull includes first and second channel defining structures connected to the hull that define a first channel on a port side of the hull with a forwardly facing first channel entrance and a second channel on a starboard side of the hull with a second forwardly facing channel entrance. According to one aspect of the invention, the hull has a bow that extends to a vertical knife edge, and the first and second wing channel entrances are arranged to form a near horizontal knife edge at the deck level in order to enhance high speed operations. According to another aspect of the invention, there is provided an onboard air system for injecting air into the first and second channels in order to enhance high speed operation of the watercraft.

Abstract: An improved boat hull which is useful for various types of boating activities; having a top or perimeter surface, curvilinear bottom surface, curvilinear side surfaces, curvilinear front and rear surfaces. Hull is formed, fabricated or manufactured as a combination of compound curves and straights. The top or perimeter of the hull is to be attached to a standard or non-standard deck configuration. The front, sides and rear of the hull are convex, concave, compound curves and straights, for engaging in contact with water and with a combination of water and air. The front end or bow section of the hull features primarily convex/outward construction in a rounded or somewhat of a ‘v’ shaped configuration, while the remaining portion of the hull graduating to the rear and exiting at the stern, or transom, features a series of concave and convex curves and straights producing a dual-hull or somewhat of a double ‘v’ tunnel configuration.

Abstract: A boat hull represented in a high speed attitude relative to a water surface-has a generally monohull section. A forward keel portion is flattened to form a plank-like planing surface having a replaceable shoe including stability extensions. Main bodies of sponsons are configured with air dams or spray walls. The sponsons define outer walls of side tunnels. The hull form, inboard of the side tunnels, provides side planing surfaces that step down transversely to the keel planing surface. Front and rear portions of the sponsons are connected by the air dam or spray walls and bound side tunnels having side planks or planing surfaces disposed at their inner edge. A step in the keel is provided to define a tunnel disposed between two downwardly depending side walls. Across afterplanes an integrated undersurface has an outboard motor insertion space with a continuation of the recess upper surface and provides a lateral boundary of a space.

Abstract: A shallow draft sports boat for use in in-shore fishing has a tunnel in its bottom allowing one to place an outboard motor higher with respect to the hull of the boat than is conventional. The tunnel is relatively short with respect to the overall length of the boat, has a small volume and is provided with a recess at its leading end and a vent communicating between the recess and the port in the transom above the water line.

Abstract: The boat is essentially mono hulled in its appearance but has the capacity wherein the lower and outer sections of the hull can be hinged out of a concave recess under the main deck and behind the full bow of the boat. The front of the hinging sections are curved to a point and graduated longitudinally to allow a bowlike profile at any given point as the sections are swung upward and away from the core of the boat. When the hinging sections are semi extended a full twin hulled operation can be achieved and when further extended a true triple hulled operation can be achieved with essentially three “bows” cutting the water. When fully extended the walls of the hinging sections come up to horizontal and also provide the benefit of extra deck space.

Abstract: The present invention relates to a watercraft having a wave suppressing “M-shaped” hull design. The hull comprises a central displacement body flanked by two downwardly extending outer skirts. The outer skirts are attached to the displacement body by planing wings having wing channels. The bow wave is directed into the wing channels, thereby increasing planing efficiency and reducing the effect of such waves on other boats and the shoreline. One embodiment takes the form of a twin-hull catamaran with two M-shaped hulls and four arcuate channels for containing the spiraling bow waves from the two central displacement bodies, thus to increase lateral stability and to suppress boat waves to protect nearby boats and structures at the water/land interface.

Abstract: A tunnel-hulled boat that has a high degree of maneuverability at low and high speeds with decreased hydrodynamic drag is disclosed. The tunnel-hulled boat is maneuverable in shallow water and when proceeding in reverse. The tunnel-hulled boat is comprised of a hull having a generally rounded tunnel that extends from proximate amidships to the aft with the depth of the tunnel increasing from its nose end to its aft end. The tunnel has a generally rounded twin entry nose and has a notched aft. A first set of bevels having increasing diameter extend along each side of the tunnel while a second set of bevels are each disposed within a respective one of the first set of bevels proximate the transom of the boat. A pair of sponsons are attached to the transom on each side of the tunnel.

Abstract: A channeled air planing apparatus improves low speed performance of boats without adversely affecting high speed performance. The apparatus includes structural elements for channeling air to a transverse step adjacent a running surface. Air channeled to the transverse step eliminates low pressure at the step caused by flow of water past the step, which in turn enhances low speed performance by lowering the bow of the boat and reducing drag on wetted propulsion equipment and other aft boat structure. In a preferred embodiment, the channeled air planing foil includes a lower hydrofoil member attached to a setback area of the boat by a pair of substantially parallel sidewalls aft and above the boat's running surface. When the boat is at rest, a channel defined by the lower hydrofoil element and sidewalls contains water. As the boat moves forwardly through the water during takeoff, water is evacuated from the channel and replaced with air which ventilates the transverse step.

Abstract: A boat hull system for reducing the friction between boats and water. The boat hull system includes a boat with a front and a rear. Towards the front there is a hull with a forward portion that includes a width tapering smaller toward the front and towards the rear there is a rearward portion that includes a substantially uniform width between the forward portion and the rear. The hull includes a lower surface with a keel ridge. The forward portion is substantially smooth between the keel ridge and a lateral side of the lower surface. The lower surface of the rearward portion includes a plurality of strake ridges extending substantially parallel to the keel ridge, and includes at least two strake ridges on each lateral side of the keel ridge. The adjacent strake ridges define a channel therebetween. An air duct extends from the lower surface of the forward portion and the lower surface of the rearward portion for moving air between the forward and rearward portions.

Abstract: The present invention relate to a watercraft having a wave suppressing “M-shaped” hull design. The hull comprises a central displacement body flanked by two downwardly extending outer skirts. The outer skirts are attached to the displacement body by planing wings having wing channels. The bow wave is directed into the wing channels, thereby increasing planing efficiency and reducing the effect of such waves on other boats and the shoreline.

Abstract: A boat includes a body having one or two paddling positions. The body is sufficiently narrow at the paddling positions to provide a comfortable paddling width. A bow extends forwardly and converges to become progressively narrower from the forward paddling position. A stern extends rearwardly and diverges to become progressively wider from the rearward paddling position. The stern has two hulls positioned rearward of the at least one paddling position and separated by a connecting surface. The connecting surface extends rearwardly and upwardly from the rearward paddling position upwardly an upper remote end that is out of the water at the stern, thereby reducing drag.

Abstract: A high performance boat hull structure is provided which combines a V-hull bottom portion 12 with mid hull sponsons 31 and 33 which form longitudinal tunnels with adjacent structures. The mid hull sponsons 31 and 33 have horizontally disposed running surfaces to provide lift at high speeds. Outer sponsons 14 and 16 incorporate running surfaces 24 and 26 and together with mid hull sponsons 31 and 33 form a second air tunnel and engage and deflect side directed spray and wake downwardly providing additional lift and decreasing or eliminating spray and signature wake. Entrance of injected or inducted air into the air tunnel area decreases frictional engagement of the hull with water to improve efficiency and ride.

Abstract: An improved method for raising a propeller up into the hull of a marine water craft for the purpose of reducing the likelihood of underwater impact and improving shallow water operation without encountering the high efficiency losses normally associated with shallow draft drive systems or water jets. It utilizes a unique tunnel which is open bottomed and extends longitudinally in the running surface of the hull. The lead in to the tunnel, which is termed the “chute” forms the entry to a deeper portion of the tunnel located further aft. A super-cavitating propeller is positioned in the aft tunnel section. The propeller is raised vertically into the tunnel such that the propeller blade tips can be above, below or flush with the running surface of the hull but the prop shaft is always above the running surface of the hull. The invention relates to the longitudinal position of the chute with respect to the propeller, the general shape of the chute and its normal method of operation.

Abstract: An air propelled boat. It is provided with a pair of catamaran hulls, each having a unique catamaran hull design particularly adaptable for travel over land, water, ice or snow. Each catamaran hull has a pair of centered concave flutes extending from the aft end of the body to the forward end of the nose. At the nose end, the flutes are reduced in concavity and inclined longitudinally and laterally. Both inclinations are reduced in slope forward. The flutes guide water outward and under the hull and move the water hull contact aft. This decreases hull drag and increases lift. The hull bottoms are formed into a central longitudinal support flat which is flanked by parallel outboard support flats. The undersurface of a catamaran hull is covered by an ultra-high molecular weight plastic profile to reduce friction when traveling over a solid supporting surface. The catamaran hulls are foam filled for rigidity.

Abstract: A boat hull of exceptional performance and stability combines a deep V entry configuration transitioning to a catamaran-like after section to produce the soft water entry that is characteristic of a deep V design together with the lateral stability that is characteristic of a catamaran.

Abstract: A tunnel-hulled boat that has a high degree of maneuverability at low and high speeds with decreased hydrodynamic drag is disclosed. The tunnel-hulled boat is maneuverable in shallow water and when proceeding in reverse. The tunnel-hulled boat is comprised of a hull having a generally square-nosed and notched aft and generally concave tunnel disposed from proximate amidships to the aft, with the concavity increasing as the tunnel proceeds aftward. A first set of bevels having increasing diameter extend along either side of the tunnel while a second set of bevels are each disposed within a respective one of the first set of bevels proximate the transom of the boat. A pair of sponsons are attached to the transom on either side of the tunnel.

Abstract: A watercraft is disclosed including an improved ride plate for enhanced handling, responsiveness and performance of the watercraft. The ride plate preferably has two grooves formed in the undersurface of the ride plate. The grooves are of continuous cross section, extend the entire length of the ride plate and are located behind the water intake duct opening. Finally, the grooves are strategically located to avoid the turbulent water caused by the water entering the water intake opening so as to increase the handling, responsiveness and performance of the watercraft.

Abstract: The bottom surface of the surfboard has a set of transverse ridges which are bowed away from the front of the surfboard, which are symmetrical relative to the longitudinal axis of the board. A channel extends across the edge surface of these ridges and are aligned along the board longitudinal axis. In motion, the moving water not only strikes the rear edge face of the surfboard but also the rear faces of each ridge, thereby increasing its propelling efficiency relative to surfboards devoid of such ridges. A second and a third sets of transverse ridges may be formed in water pockets made on opposite lateral side surfaces of the surfboard. These second and third ridge pockets assist in self-straightening the surfboard should the latter accidentally swerve at least slightly transversely from the general axial direction of displacement.

Abstract: A propulsion system for high-speed powerboats whereby the water level in a tunnel containing a surface-piercing propeller is controlled by admitting external air into the tunnel through an air outlet in the tunnel forward of the propeller. The air is admitted through a duct which has an air intake on the exterior of the boat. The duct may contain a valve which may be opened or closed to control the air supply. Particular configurations of the tunnel and the air supply system are disclosed which maximize the ability to control the water level in the tunnel and the degree to which the propeller is submerged as well as best utilize the configuration of the vessel.

Abstract: A planing vessel has a hull and a propulsion and control system. The hull has a plane bottom formed of an equicrural triangle in the front and a rectangle at the back, two boards and one or more swell guideways. Each swell guideway has an inclined top line with a lower front and a higher back denting upwardly into and extending lengthwise throughout the bottom and paralleling its centerline. The hull also has a pair of wave-splash guards inlaid or dented one into the boards as an integrated body, a deck, a cabin and an upper construction. The planing vessel so formed can generate sufficient hydrodynamic buoyancy with reasonable distribution to quickly lift itself out of the water and enter a planing state. The planing vessel can have various fine performances, desirable speed and stability to move on rough waters.

Abstract: An apparatus for reducing drag over a flow surface and methods for using same is disclosed in one presently preferred embodiment as including a drag reduction member comprising a means for reducing drag over a surface facing of a substrate (e.g., watercraft, airplane, automobile, airfoil, rudder, or the like) moving through a fluid (e.g., liquid or gas) parallel and opposite to the direction of motion. The drag reduction member includes an exterior surface, an opposing contacting surface adapted to selectively cover at least a portion of the surface facing of the substrate, and an opening integrally formed in the body of the drag reduction member to enhance flexibility upon installation and provide greater resistance to impact forces. The opening may be sealable by means of at least two extension wings engageably disposed in relation thereto.

Abstract: A boat hull is disclosed having a bow and a stern. The hull includes a pair of elongated sponsons, each having a lower surface adapted to contact a water body having a water level. The sponsons are spaced apart and generally parallel to each other and form a channel therebetween. An aerodynamic member is positioned within this channel. The aerodynamic member includes an air compression section which slopes downwardly from the bow to a midpoint of the hull. Similarly, an air decompression section slopes upwardly from the midpoint of the hull and towards the stern. In operation, the aerodynamic member is dimensioned such that, upon forward movement of the hull through the water body, the compression of air flow through the channel by the air compression section and subsequent decompression of the air by the decompression section is sufficient to elevate water in the rear portion of the channel above the water level of the water body.

Abstract: A small watercraft hull is shaped to prevent spray from being splashed on occupants of a watercraft, to enhance the course stability of the craft during turning, and to reduce the resistance of the craft body 3 to the water. A longitudinal chine, extending in a longitudinal direction, and rearwardly curved transverse chines extending in transverse directions and located in the fore part of the craft body, are provided on a V-shaped hull bottom of the craft body, the transverse chines being so formed as to cross the forward part of the longitudinal chine or an imaginary line extended forwardly from the longitudinal chine.

Abstract: A boat hull configuration that generates lift upon forward movement in the water caused by two lateral side keels that run along either side of the hull, and a bottom surface that joins the two sides keels, wherein the forward portion of the bottom surface has a concave configuration which provides a pivot fulcrum surface, and wherein the forward portions of the keels have an inward slant from the front rearwardly to channel and trap water and air under the hull and result in the development of a force directed upward against the fulcrum surface to produce planing lift during powered forward motion of the boat.

Abstract: A boat hull constructed with an inverted U-shaped hull bottom, hull sides which are vertical below the at-rest water line and outwardly curved in a deep arc above the at-rest water line, and a rudderless, arcuate concave tunnel from bow to stern is disclosed. Preferably, the port and starboard gunwales are parallel and the port and starboard chines are parallel. The inventive boat hull is capable of smoothly and rapidly assuming a hydroplaning position without use of submerged hydrofoils, and without pounding upon waves. The hull is navigable in fouled water, substantially reduces water sprayed aboard, and eliminates "tripping" when navigated through sharp turns.

Abstract: This tunnel-hull uses non-linear flow means to maximize tunnel lift efficiency, fuel economy, and directional stability. The lower lateral hull planing surfaces have sharp, wedge-shaped step discontinuities defining multiple flat, smooth, planing surface sections having zero dead-rise angle. The steps decrease wetted surface area and increase hydrodynamic traction without adding draft. Downwardly extending curved lateral hull portions define a tunnel between their parallel inner edges. Random impressions in the undersurface of the tunnel relieve vacuum suction and create non-linear air flow for greater lift. Downwardly bent front edges of the tunnel and rear delta wing swim platforms are control surfaces that serve as safety brakes and prevent flipping. Tunnel air pressure increases in a gradient from bow to stern placing the center of lift aft of the center of mass, which provides safety from undue inclination and extra shock absorption.

Abstract: A high speed, high efficiency, stable catamaran boat hull which comprises a boat hull structure having an under surface, a curved bow and a generally flat stern, a pair of spaced-apart sponsons on either side of the keel line of the hull and extending generally substantially from the bow of the hull, wherein the sponsons generally come to a point, to the stern of the hull. The sponsons generally have vertical, downwardly extending, inner side walls and a generally horizontal underwall connecting the inner walls to form an air tunnel, the inner side walls tapering inwardly from the bow to the stern of the hull structure to compact the air passing through the tunnel to lift the hull in operation.

Abstract: A hull for a boat comprising a main hull bottom having a pair of hull bottom sides, each side having a first longitudinal inner edge and a second outer edge, with the hull bottom sides connected along the first inner edges and extending transversely upwardly and outwardly therefrom in a generally "V" shaped transverse cross section, each of the hull bottom sides having a main portion angled outwardly and upwardly from the first inner edge, and each of the hull bottom sides having a chine angled outwardly and downwardly from the main portion along a majority of the length of the second edge, a substantially vertical transom at the aft ends of the hull bottom sides, and a pair of raised after planing surfaces having forward ends at the transom and projecting aft of the transom and substantially parallel to and stepped slightly above the hull bottom sides immediately in front of the after planing surfaces, and the raised after planing surfaces also projecting aft generally parallel to and slightly above the chin

Abstract: The present invention relates to a hydrodynamically designed concave hull having longitudinally positioned chined rails at the outermost edges of the concave scoops. Each pair of concave scoops have a central longitudinally positioned median V-shaped groove to channel water and facilitate steering of the hull.

Abstract: This invention relates to a marine vessel hull form, in particular to a high speed planing boat. It describes a new and distinctive shape of hull which, unlike other hull forms developed to date, features the shape which modifies the flow of water underneath and around it in such a manner that the waves behind the hull at speed are reduced to a minimum. This hydrodynamic effect results in reduced resistance and thus increased speed and/or reduced fuel consumption. Further, it will result in reduced wash behind the boat, an effect that will enable it to operate at full speed near shores where local regulations limit crafts' speed because of shore erosion caused by waves generated by boats and ships. The hull form described in this invention offers more stability than the planing traditional hulls do, due primarily to higher beam to length ratio and to the stern shape, which departs from the traditional "V", which is not particularly stable at speed or stationary.

Abstract: A planing boat having a stern and a bow includes a hull having a generally flat central bottom surface forming a portion of a pad with the surface tapering from a specified width at the stern towards the bow. Reverse wedge surfaces blended with the central bottom surface at the stern and deadrise surfaces blended with the central bottom surface and intersecting with the reverse wedge surfaces continue forward towards the bow. The rear portion of the flat bottom surface is tipped upwardly towards the stern.

Abstract: An improved aerodynamic surface for the exterior of vehicles moving through a gas and vehicles employing such improved surfaces. The improved surface comprises a matrix of dimples or depressions formed into the portions of the surface of the vehicle. The improved surface is most beneficially located either at a leading edge, where the vehicle first cleaves the pool of air through which it is traveling, or on vehicle surfaces which tend to move the air pool to accommodate the presence of the vehicle itself or on vehicle surfaces to which the designer wishes to provide a lift function. Wings, ailerons and rudder surfaces are examples of surfaces to which a lift function is most applicable. The vehicle may be of the nature of an automobile, a boat or an airplane. The invention is also applicable to the internal surface of pipes for conveying fluid.

Abstract: A catamaran for pastime, model construction or racing with induced hydrodynamic stability, having a hull with a board (1) and a pair of longitudinally extended semi-immersible appendages (2, 3; 8, 9; 13, 14; 24, 25) arranged parallel to each other symmetrically to the center-line of the hull, the respective bottoms of which, at the bow tips (4, 5; 12, 12a; 21, 22; 32, 33) of said appendages, have mutually opposite slopes, each slope being contrary to the slope of the respective aft rest of the bottom with respect to the median symmetry plane of the hull.

Abstract: The present invention is an improved boat hull construction, in particular for power catamarans. The individual hulls incorporate step breaks to define individual planing sections with different constant deadrise angles. Twist or warp is thereby eliminated in these sections, reducing drag and increasing efficiency. The step breaks also allow individual outboard chine flats which reduce in width from aft to fore. The catamaran tunnel features a decreasing section to compress air and provide a cushioned ride.

Abstract: A surface for use in connection with an object in relative motion through a luid medium includes a plurality of surface elements arranged in rows on the surface, with surface elements of each row being arranged generally orthogonal to the direction of relative motion of the object in a medium. Each surface element includes means defining a cavity, the means including a bottom surface layer, sidewalls, and an upper lip supported along an upstream edge in a cantilevered manner and extending in a downstream direction over the cavity to define a gap permitting fluid communication between the medium and the cavity. The lip is flexible so as to facilitate deflection in response to differentials between pressure inside the cavity and outside the cavity. The cavities of the surface elements in each row are interconnected by means of passageways thereby to facilitate fluid communication therebetween.

Abstract: A vehicle for travel on snow or water consisting of an elongated main member having a top and a bottom surface with a venturi effect. First and second runners extend lengthwise and downwardly along opposed edges of the bottom surface from a point spaced rearwardly of the front end of the member to a point spaced forwardly of the rear end of the member. The runners and bottom surface define the venturi section that tapers inwardly to a narrow throat in the vicinity of the middle of the member and then tapers outwardly. Elongated side cuts are provided to the elongated outside surfaces of the board, the side cuts creating a surface which is narrower in width between the front and the back of the surface.

Abstract: A hydrofoil craft according to the invention is provided on the bottom of the hull with at least one, usually several, air cushion recesses arranged along the middle of the bottom in a fore-and-aft direction. The air cushion recesses each forms a groove having the upwardly indented bottom, the upper wall front end, to be deeper and becoming shallower toward the rear end and resembling a triangle or sector in shape when viewed in a longitudinal section and generally to be a rectangle in shape when viewed in a plane. The angle from the shallowest end of the air cushion recess to the deepest end is within 1.degree. to 30.degree. and the two side walls on the sides of the bulwarks of the recess extend a little to the lower parts of the fore-and-aft end walls. The hydrofoils are mounted across the lower parts of the air cushion recesses and are close to the air cushion recesses.

Abstract: A displacement ship having a hull, a stern 6 which at least in the region of the underwater body form a flat surface to which the longitudinal axis of the ship is a normal, the hull at least in the region of the underwater body, narrowing towards the stern 6 neither with the side surfaces 1a, 1b nor with the bottom 1c.

Abstract: To reduce the total ship resistance and to improve a propeller efficiency and cavitation performance due to the reduced thrust loading on the propeller for ships or vessels having a sonar dome or an equivalently shaped designs located below the baseline of the hull, a teardrop-shaped bulbous bow is attached to the ship stem bow between the forward perpendicular of the bow and 12.7 ft forward of the forward perpendicular of the vessel, inclusive, and between the ship design waterline and the baseline. The bulbous bow is separate and discrete, and spaced from the sonar dome and has a shaped of a teardrop. The teardrop shaped bulbous bow is mounted to the ship stem bow with the round end portion pointing in the forward direction and the pointed end portion pointing in the aft direction.

Abstract: An accessory rail adapted to be attached to an existing spray rail of a boat bottom is disclosed. The accessory rail includes a mounting portion having a first supporting surface adapted to abut a substantially vertical surface of the existing spray rail, and a rail portion extending downward from the mounting portion and including a water deflecting surface. The rail portion includes a second supporting surface adapted to abut a substantially horizontal surface of the existing spray rail. The water deflecting surface may be a flat or a curved surface.

Abstract: A textured bottom surface is provided for bodyboards of the type which have a semi-rigid foam core and which are used to ride on waves such as ocean surf with the rider in a prone or procumbent position. The improved bottom surface comprises a plurality of discreet depressions formed in the bottom of the bodyboard, numbering at least 50-depressions over the entire bottom surface, and preferably numbering more than 1500 such depressions. The depressions are believed to generate bubbles in the air-water mixture passing beneath the board which help reduce the shear forces in the water. The effect is called air lubrication and results in reduced drag and greater speed, as well as a lighter "feel" for the board on water. A bodyboard incorporating the improved bottom surface, and a bottom skin for bodyboards which includes the texturing depressions, are disclosed. A method of forming the textured bottom skin is also disclosed.