Abstract: A boat stabilizer for attachment to the lower drive unit of a boat motor. The stabilizer comprises a first lifting member having a first interior side wall for positioning adjacent to a first side of the drive unit and a first arm portion for extension around the drive unit, and a second lifting member having a second interior side wall for positioning adjacent to a second side of the drive unit and a second arm portion for extension around the drive unit toward the first arm portion. The second interior side wall is spaced from and opposes the first interior side wall forming a slot therebetween for receiving the drive unit. The first and second arm portions are removably attached together and selectively movable toward and away from each other for varying the width of the slot. The ability to vary the width of the slot for receiving the drive unit allows the stabilizer to be adjusted to fit virtually any conventional outboard or inboard/outboard boat motor.

Abstract: A "fish-shaped" hydrofoil section and in particular, a hydrofoil section having a body of cross-sectional area increasing in thickness from the leading edge to a point near the midchord of the hydrofoil section. The thickness of the body then decreasing some amount to a local minimum, and thereafter increasing along concave surfaces in a "fishtail" flare to a local maximum thickness at the trailing edge. A low pressure area develops behind the trailing edge of the "fishtail" flare and is ventilated with gas at a pressure greater than that of the developed low pressure area. The cross-sectional shape of the hydrofoil section can be symmetrical or cambered.

Abstract: A reduced-drag, axially symmetrical missile or submarine hull with rounded, tapered bow and stern portions, and a rounded central portion tapered, for drag minimization, along a curve defined by a Fredholm equation of the second kind framed so that the pressure coefficient remains constant at all points on the central portion. The missile is designed to travel within a fluid so that its drag coefficient is decreased, boundary layer detachment is avoided, and cavitation and instability phenomena are eliminated. The constant pressure coefficient is reached by following as a profile the natural track lines of the front portion which are joined to the rear portion.

Abstract: A lift producing device is disclosed which is adapted to be connected to a vehicle to provide lift to the vehicle when the vehicle is moved relative to a first fluid medium having a first density and viscosity and being in contact with a second fluid medium adjacent the vehicle. The second fluid medium has a second fluid density which is different from the first fluid density. The lift producing device comprises opposed first and second major surfaces joined at a longitudinally extending leading edge and at a longitudinally extending trailing edge, with at least a portion of the longitudinally extending leading edge being spaced from the longitudinally extending trailing edge by a predetermined mean chord length.

Abstract: A flying boat or sea plane has a wing system in order to obtain hydrodynamic lift when protracted and including two wings arranged one above the other but establishing, in front view, a closed frame; the wing system can be retracted into the fuselage of the vehicle by turning the wings upside down and pulling them into the fuselage using a three-group lever system.

Abstract: An apparatus for automatically raising and lowering boat motors includes a mounting configuration that allows the motor to move up out of the water and down into the water. A hydrofoil is connected with the motor. When the boat is propelled by a second motor, the water pushes up on the hydrofoil, forcing the first motor up out of the water. A locking device can be used to maintain the first motor in the up position. The locking device can be disengaged to allow the motor and hydrofoil to fall into the water. Alternatively, the motor and hydrofoil can be maintained in the up positon by the force of water against the hydrofoil. When the second motor is shut down the motor and hydrofoil automatically drop into the water.

Abstract: Disclosed herein is a propeller guard device, including a laterally extending fin and a vertical extension, or sleeve. The fin and sleeve could be manufactured as a singular item. The vertical sleeve is attached to the midline area of the fin, with the leading edge of the sleeve being generally co-terminus with the leading edge of the fin. The fin is at least as wide as the rotational path of the propeller blades. The singular fin extends laterally on either side of the sleeve in a generally coplanar relationship. The leading edge of the fin is elevated from three to five degrees higher than the trailing edge of the fin. The trailing edge of the fin is located forwardly of the rotational path of the propeller blades, or is lengthened and extends towards the rear of the device to the extent of being even with the midline of the rotational path of the propeller blades.

Abstract: The invention relates to a profiled device configured as a slotted blade head to improve the efficiency in blade-like structural elements that have a gas or a fluid flowing around them such as foils, vanes of jet engines, propellers, keels of ships or the like. The blade head is formed of a group of profiled blade elements (3) having a laminar profile with radially running slots formed between the blade elements at a distance from the base of blade head. End edges (4) of the blade elements (3) that are consecutive in an initial flow direction (X) are offset relative to each other each in the direction of a pressure zone (6). Slots (2) between the blade edges (4) are of a nozzle-shaped configuration with a flow direction extending from the pressure zone (6) to the underpressure zone (5). The blade elements (3) are located within a profile envelope (73) set by the blade base of the group of blade elements.

Abstract: A hull (5) of a planing boat (1) consists of front and rear hull portions (5a, 5b). A bottom part (2a) of the front hull portion (5a) forms one front planing portion (21a), and a recess (7) is provided so as to extend along the center line of the rear hull portion (5b), two bottom parts (2b') either of which is positioned on the left or right side of this recess (7) forming two rear planing portions (21b). When the speed of the planing boat (1) is low, it runs with the front and rear planing portions (21a, 21b) completely submerged, and, when the speed of the planing boat (1) is high, it floats and plans on the water surface with the hull (5) supported on three portions, one front planing portion (21a) and two rear planing portions (21b).

Abstract: An apparatus for automatically raising and lowering boat motors includes a mounting configuration that allows the motor to move up out of the water and down into the water. A hydrofoil is connected with the motor. When the boat is propelled by a second motor, the water pushes up on the hydrofoil, forcing the first motor up out of the water. A locking device can be used to maintain the first motor in the up position. The locking device can be disengaged to allow the motor and hydrofoil to fall into the water. Alternatively, the motor and hydrofoil can be maintained in the up position by the force of water against the hydrofoil. When the second motor is shut down the motor and hydrofoil automatically drop into the water.

Abstract: Each stabilizing fin is provided with a thickened trailing edge in order to act as a flap for inducing drag during start-up. The induced drag serves to minimize the time within which the fin moves into a planing position. The recess on the bottom surface of the fin enhances the lifting force on the fin during stabilization without imposing undue drag forces during high speed travel of a boat.

Abstract: The improved watercraft comprises an underwater pod or pods, that support a pecentage of the displacement of the watercraft at rest. The percentage of displacement produced by the pods could vary widely based upon the purposes of the watercraft and its intended range of uses, i.e., speed, water conditions, cargo, length, etc. The improved watercraft is also comprised of one or more hulls at the surface, which when at rest, displace most of the remainder of the watercraft's total weight. The rest of the watercraft's displacement, normally a small percentage, is comprised of hydrofoils, or wings, and these provide lift for the watercraft when under way. These hydrofoils or wings would normally be designed to be sufficient in area and dynamic lift to raise the surface hull clear of the water's effects, if that was desirable for the intended purpose.

Abstract: The Disclosure is concerned with lift and rudder fin attachments for outboard engines and inboard engines with outboard drives of the type used in the propulsion of boats. The attachments may be adjusted to vary the amount of lift that is produced under a given set of operating conditions, and they also have the added advantage of greatly enhancing steering control at slow speeds and during slow speed operations such as trolling and docking.

Abstract: A boat comprising a tube-like hull (1), a hydrofoil (2) fixed to its front portion, a pair of wings (4) hinged to each side of its rear portion, a fin (20) fixed to its rear bottom portion, an out-board-type motor (9) provided in its center of gravity, and a steering lever (14) that can be rotated and also tilted. Rotation of the lever (14) causing rotation of the motor (9) and steering the boat. Tilting the lever causing lifting or lowering the wings (4). Each wing (4) has a float (5) fixed to its end. When the boat stops and at low speed the floats are in the water. When the boat at high speed an operator gives lift to the floats out of the water. At highest speed an operator puts the wings in parallel with the water surface and a ground effect is used. Central location of the motor contributes the boat to go into hydroplaning at low speed and gives lift to the rear portion of the boat using water pressure created by a propeller. The most controlable boating and efficient usage of motor power are provided.

Abstract: A hydrofoil propulsion system (10) utilizing dual water propellers (16) in combination with dual shrouded air propellers (18). The air propellers (18) and the water propellers (16) are powered by diesel engines (22) mounted in pairs inside the hull (24) of the hydrofoil craft (b 14). Each water propeller (16) is affixed to an outdrive 35 through a pivotal propeller shaft (28) that permits the propeller shaft (28) and the water propeller (16) to move horizontally and vertically with respect to the hull (24). An air propeller (18) and a water propeller (16) are each coupled to a single pair of engines (22) so that as the craft (14) transitions from the hullborne mode to the foilborne mode, the thrust load is automatically transferred from the water propeller (16) to the air propeller (18).

Abstract: Hydrofoil craft, particularly a method of economically modifying a conventional hull by means of foils to obtain enhanced lift and rough water stability. The method is characterized by defining an axial tunnel(s) intermediate the bow and transom of a catamaran hull or V-bottom hull modified with chine mounted aerofoils; positioning a flexible dihedral foil beneath the water line and on either side of the bow so as to obstruct and create a turbulence in the forward end of the tunnel, while cushioning shock and lifting the bow; and simultaneously enclosing the transom end of the tunnel with a foil, so as to compress the turbulence and lift the transom.

Abstract: Hydrofoil families which have high lift and low drag coefficients. Induced vorticity is partly suppressed by introducing a longitudinal component of the flow directed from the foil tip towards the hydrofoil base at least in the area of the hydrofoil tip. Further increase of the hydrofoil efficiency is attained by reducing the low lift and high drag induced vortex enhancing area along the tip. For given lift requirements the foil area can be reduced and cavitation performance improved. High torsional and bending resistance are attained by using high modulus materials arranged in chosen directions.

Abstract: A water and air supported vehicle propelled by the wind. The vehicle includes a long narrow hull (30) that displaces water at low speeds and a plurality of hydrolfoils (36) distending from the hull in communication with the water resisting lateral loads and at high speeds partially supporting the vehicle. An airfoil (38) whose section is suitable for a membrane surface is pivotally attached to the hull and acts to partially support and provide thrust to propel the vehicle. A strut and a plurality of tendons (58), (60), (62), (64) and (72) position the airfoil relative to the hull (30) and articulate the airfoil when manually actuated. The shape of the airfoil tips elements (46) provide vehicle roll resistance when they penetrate the water surface and a payload is supported by a hull torque link (66) and a cantilever beam (90) with a sling (92) positioned therebetween. Other embodiments articulate the hydrofoils in concert or include a payload containing capsule (112).

Abstract: A tetrahedrally shaped pivotable sailing frame of four spars and a sail with balanced hydrofoils is disclosed. A hydrofoil sailboat is created by pivotally attaching the frame to a hull along a longitudinal axis of the hull. Tacking is accomplished by rotation of the frame about that axis. Although the sailing frame can be adapted to a variety of types of hulls, including windsurfers, catamarans, and multiple-hulled craft, a preferred embodiment of a hull is disclosed which in combination with the sailing frame affords the proper lift and forward vectors and obviates the need for a keel, live or dead ballast, or sail adjustments. The lift affords very high speeds and minimal wetted surface. The tetrahedral structure of the sailing frame is stiff, giving a level, stabilized ride and permitting an optimal surface area of sail. The hull design provides swift, easy tacking and reduces the possibility of backwinding.

Abstract: A sea-going craft has a main central body with two wings affixed to the body and extending horizontally away to either side. A catamaran-type hull is attached to each wing end, and provides flotation. The rearward edge of each wing is generally closer to the water than the forward edge when the craft is under power, thus adding lift due to the ground-effect phenomenon. A hydrofoil is affixed to each hull and extends downwardly, and a third hydrofoil is affixed to the central body, extending downwardly. The craft includes propulsion apparatus.

Abstract: An improved hull construction for a SWATH vessel of the type having first and second pontoons disposed beneath a superstructure and coupled thereto by vertically disposed struts. The improvement comprises substantially hollow sponson whose bottom surface defines a relatively narrow horizontally extending strake disposed between the superstructure and each pontoon for producing forces to right the vessel including substantially instantaneously increasing the rate of buoyancy as the superstructure contacts the water surface. In the preferred embodiment, each sponson extends fore and art of the vessel for substantially the entire length of the struts, and includes a bottom surface defining a strake located a prescribed distance below the superstructure for increasing the waterplane area by a prescribed amount when the bottom surfaces of the sponsons contact the water's surface.

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.

Abstract: Hydrofoil craft, particularly a method of economically modifying a conventional hull by means of foils to obtain enhanced lift and rough water stability. The method is characterized by defining an axial tunnel(s) intermediate the bow and transom of a catamaran hull or V-bottom hull modified with chine mounted aerofoils; positioning a flexible dihedral foil beneath the water line and on either side of the bow so as to obstruct and create a turbulence in the forward end of the tunnel, while cushioning shock and lifting the bow; and simultaneously enclosing the transom end of the tunnel with a foil, so as to compress the turbulence and lift the transom.

Abstract: A propulsion system capable of more efficiently accomplishing all that the prior art propulsion systems can accomplish and additionally providing for manuevers that had hereto been unavailable with purely stern-driven craft through the use of a first and second apparatus for generating propulsion mounted at the rear of the craft to be driven. The two apparatusses for propulsion are arranged one over the other so that the centerlines are substantially aligned vertically. A movable rudder is mounted substantially vertically at the rear of the craft parallel to the centerline of and in the effluent streams of the first and second propulsion apparatus. A fixed fin array is also mountede at the rear of the craft in the effluent streams of said first and second propulsion apparatus just forward of the rudder.

Abstract: A water deflector or splash guard for diverting water away from the powerhead and bracket assemblies of an outboard motor during operation of a boat. The splash guard includes a flat planar head portion extending forwardly of the gearcase and a body portion extending rearwardly of the head portion comprising a pair of spaced apart fin members disposed on opposite sides of the gearcase. In one form, the splash guard is substantially U-shaped and is mounted between the anti-ventilation plate and spray plate of an outboard motor exteriorly of the outer surface of the gearcase. In another form, the splash guard includes an integral tail section and is mounted by being sandwiched between the gearcase and drive shaft housing.

Abstract: A unique water ski device for use with a tow rope for allowing the rider to ride on, above or below the surface of the water, includes a riding platform rigidly affixed above a hydrofoil by a detachable bent pole, flanged on each end, so that it can be dismantled for easy transport and storage. The riding platform has a ski handle affixed by ropes for use by the rider as a balancing aid. The riding platform has a nonskid surface for the safety of the user. The length of the pole can be of various lengths up to and above 10 feet in length. The device is towed behind a boat by means of a two rope which is affixed to the forward end of the riding platform. The rider rides on the top of the riding platform in a standing position and by shifting his or her weight forward or backward controls the height of the device above, on or below the water surface.

Abstract: A high speed vessel system comprises a surface-craft, a sub-craft, a pair of main foils, at least a pair of auxiliary foils, a narrow strut connecting the sub-craft with the surface-craft. The main propeller and main rudder are located at the stern end of the sub-craft hull. When the vessel system is cruising at a high speed, the surface-craft will be lifted above the water line mainly by the buoyant force of sub-craft hull. The foils will control rolling and pitching of the vessel system. The surface-craft and sub-craft will be connected by a separable ball joint (first embodiment) or a plurality of rotatable links (second embodiment) when the vessel system is in sea operation. The sub-craft can be raised up to the water surface level to minimize the draught of the vessel system when the system is resting in a harbor. The present vessel system is specifically designed for a sea going vessel of big size and large tonnage, which needs to cruise at high speed constantly.

Abstract: A thrust collar is disclosed for mounting around the upper portion of the propeller of an inboard/outboard engine. Each thrust collar supports a horizontal hydrofoil wing extending laterally from the collar. A second, similar wing can be provided on an opposing side of the collar. Where the collar is used in pairs on paired engines on a catamaran hull, a single hydrofoil wing can be supported between the thrust collars. The thrust collar is preferably used in conjunction with hull lifting structures. One hull mounted hydrofoil structure is supported at the lower end of the strut extending and includes a generally curvilinear gull-wing shaped lower surface. For V-type hulls, a pair of elongataed mechanical lifting structures, symmetrically positioned on either side of the keel substantially in the vicinity of the keel are attached to the hull so as to extend generally traversedly to the sloping side surfaces of the hull intersecting at the keel.

Abstract: Hydrofoil marine apparatus comprising a hull, a pair of hydrofoils, each including first and second planar surface portions, pivotal mounting apparatus for mounting the pair of hydrofoils onto the hull, and apparatus for selectably and variably determining the dihedral angle between the first and second planar surface portions.

Abstract: A hydrofoil apparatus for attachment to a marine vessel having a first pivot means for positioning the rotational axis of a gooseneck shaft parallel to the yaw axis of the hull and a trailing load support arm having a forward end coupled to the gooseneck. A planing surface sensor or planing foil rides on the water surface. The planing surface provides a hydrodynamic force to hold the planing surface sensor on surface as the vessel moves with forward velocity. An elongated body member is pivotally coupled to rotate on a first pitch axis with respect to said planing surface sensor. The elongated body member is pivotally coupled to the trailing load support at its aft end. A vertical fin is coupled to support the elongated body member. The fin maintains the planing surface sensor forward of said second pitch axis. A lifting foil raises the bow of said marine vessel by provide a lifting force via the fin.

Abstract: A catamaran including two hulls defining a tunnel between them. The tunnel is bridged below the waterline by transversely arranged hydrofoils. The relatively larger mainfoil is located behind, and the smaller trimfoil in front of, the longitudinal center of gravity of the catamaran. This arrangement considerably reduces the high hump resistance of the catamaran.

Abstract: Hydrocraft, capable of maintaining comfortable seaworthy performance at both low and high speeds, in both calm and rough seas, wherein its hull form coordinates high efficiency of at least two zero deadrise planing surfaces with a wave piercing, wedge effect bow segment. The forward portion of the respective concave sides of the bow intersect at the centerline of the hull. The sides of the forward body of the hull rise from the bottom at the chine, vertically then upwardly and outwardly in a concave curvature, the form of which will load the side skin in tension. At a preselected point above the hull bottom, the sharp edged bow is truncated in a conical, forward sloping surface to provide an upward hydrodynamic force to lift the hull over waves which are higher than the gunwale. The parallel after body is located above the after planing surface, and a conical transom closes the stern.

Abstract: A hydroplaning wing sailing craft comprising a single buoyant hull having mounted transversely across the hull a hydroplaning wing having forward sweep and inverted gull wing shape. The wing having a positive angle of incidence providing hydroplaning lift and buoyancy to counteract the heeling moment and thrust of the sail. Mounted atop the hull and the wing is a high aspect ratio sailing rig. Mounted to the stern of the hull is a biaxial control system permitting simultaneous control of the direction in which the craft moves as well as the pitch attitude of the hull and thereby the angle of attack of the hydroplaning wing.

Abstract: A watercraft has a hull that is further supported above the surface while underway by a ski and integral hydrofoil, the hydrofoil is semicircular and is affixed to the hull and ski.

Abstract: The invention discloses a catamaran type boat having two similar boat demi-hulls which are spaced apart and which are substantially parallel, each demi-hull having a base line (BL). The boat further includes a superstructure connecting the two demi-hulls transversely; an open space in the form of a tunnel defined between the superstructure and the two demi-hulls; a longitudinal center of gravity position (LCG) for the boat; at least one trim hydrofoil having a chord line (CL) extending between its leading edge and trailing edge and being located in the stern region of the boat and extending at least partially across the tunnel; and an attachment element for attaching all hydrofoils to the demi-hulls substantially along a transverse plane (TP) which is substantially at right angle to the longitudinal vertical center plane of the boat, and having an angle of between 1.degree. and 7.degree.

Abstract: A propulsion system for crafts and ships, notably sailing ships, includes at least one flexible or rigid sail, to which are attached one or several foils, eventually provided with small floats, whereby the foils can be eventually articulated relative to the sail, so that the pair constituted by the sail and the foils forms a unitary block which allows cancelling a capsizing torque acting on the craft.

Abstract: Disclosed is apparatus for sealing the surface spaces between and along the leading portion of a hydrofoil (16) and its movable flap (18). The apparatus includes an upper seal member (44) and a lower seal member (46) that are joined together by a spring-biased retention assembly (53). The seal members (44, 46) are joined at one edge (51) to the trailing edge of the leading portion of a hydrofoil. The trailing edges (45) of the seal members are maintained in continuous slidable contact with the leading edge (37) of the hydrofoil flap (18).

Abstract: A catamaran stabilization structure for catamaran sailboats which includes a centerboard and dagger-boards. The centerboard has a double wing stabilizer with adjustable pitch. The dagger-boards protrude through each of the hulls. Each dagger-board has a single wing stabilizer.

Abstract: Wind surfing hydrofoil apparatus for enabling hydroplaning of a wind surfing board having a mast mounted centrally thereon between a front end portion and a rear end portion of the board, and comprising a front hydrofoil mounted on the board in juxtaposition to the mast for hydroplaning support of the board; and a rear hydrofoil mounted on the board rearwardly of the mast for hydroplaning support of the board and releasable mounting apparatus for clamping engagement with the board and a dagger board attached to the board between the front hydrofoil and the rear hydrofoil and extending rearwardly within the rear hydrofoil.

Abstract: A stabilizer for boats, the stabilizer being of generally delta planform, having a positive upper camber and a negative lower camber in chordwise cross section, being mountable upon a propeller post and in adjacent spaced relation from the propeller and adapted to be submerged, the stabilizer providing a lifting force to the stern, a downward force to the bow and a generally stabilizing affect upon the boat to which it is adapted.

Abstract: An easily detachable storage tank for use with existing hydrofoil ships is onnected to the ship by two struts with minimal modifications to the ship. The shipboard connections are such that the ship is also usable without the storage tank. The tank may store fuel in a plurality of cells having a diaphragm separating the fuel from ballast seawater. Weapons may also be stored in the tank and fired directly from the tank.

Abstract: A hull is provided including opposite longitudinal upstanding outer sides and a central depending longitudinal displacement-type keel. The forward ends portions of the outer sides and the keel curve inwardly and upwardly, respectively, and merge to form a forwardly and upwardly tapering bow. The lower portions of the sides, rearward of the bow, terminate downwardly in downwardly and outwardly inclined outer side surfaces of opposite side downwardly and outwardly inclined displacement-type cutwaters whose lower marginal portions are rearwardly and downwardly inclined. The cutwaters include inwardly and upwardly inclined inner side surfaces extending longitudinally thereof and which diverge upwardly away from the corresponding outer side surfaces.

Abstract: A hydrofoil sailboat comprises forward and aft surface piercing hydrofoils and an asymmetrical wingsail. Both hydrofoils have an inverted arch configuration and have a cross-section which is approximately a circular segment. The wingsail has a reversible asymetry, is carried on a cantilevered rotatable mast and includes a sail sock that is highly tensioned between a single top frame member and a bisectional articulated bottom frame member, the asymmetry of the wingsail being defined by the relative position of the bottom frame member sections.

Abstract: A combined, liner retainer and seal for use with hydrofoils in which fluid foils have trailing control flaps, keyed together. The control flaps are hingedly engaged to the trailing end of the foils and are rotated on the hinge for control purposes. The flaps are segmented to form a series and in each pair a key extends from a driving flap into a keyway in a driven flap so that the flaps are rotatable together. There is an elastic liner within the keyways and into which the key fits, the liner serving to protect the metallic surfaces of the keys and keyways. The combined seal and retainer extends between the flaps from the trailing end of the foil to the trailing edge of the flaps and has openings through which a hinge pin and the key extends. The retainer is elastic and holds the liner within the keyway so as to prevent its dislodgment and destruction.

Abstract: An improved leading edge contour for control flaps of the type suitable for use with hydrofoil vessels and the like wherein discontinuities or gaps between the leading edge of the flap and the trailing edge of the fluid foil to which it is attached are held to a minimum; yet, wherein localized or discontinuous differential deflection of the flap leading edge and the foil trailing edge, which inherently occurs as the vessel moves through a fluid medium, does not result in interference between the two edges, thereby minimizing the problem of reduced fatigue life; and, wherein excessively large discontinuities are not required between the two edges in those edge areas where no significant differential deflection occurs, thereby significantly improving the performance characteristics of both the flap and the flap/foil combination.

Abstract: A surfboard with a fin is developed to counteract the tendency for skegs or fins to "pop out" especially when the surfer "walks the nose" of the surfboard or rides high on a wave. The fin has a pair of opposed wing hydrofoils extending laterally from an approximately mid-point position on a vertical hydrofoil having a forwardly arcuate relieved portion above the wing hydrofoils, a downwardly-rearwardly swept leading edge and a rearwardly-upwardly swept trailing edge terminating at the confluence of the rear edges of the wing hydrofoils.

Abstract: A hinge assembly between a lifting foil (12) and an associated flap (14) wherein the flap (14) includes a series of sections (20, 22). In one embodiment, each section (20,22) may be rotatably mounted by a single hinge (24) to the foil (12) and interconnected by a coupling device (34) to an adjacent flap section. Additionally, a shear key coupling device (40) may be arranged between each pair of sections (20, 22) substantially extending to the trailing edge of each section (20, 22).

Abstract: An improved fluid fence which reduces drag on solid objects moving through a fluid environment and an airfoil or aircraft wing structure having an improved open fence on its surface improving the lift-to-drag characteristics of the airfoil.

Abstract: A hinge arrangement between a lifting foil and a flap. The flap comprises a plurality of sections. Each section is mounted by one coupling restraining hinge device to the foil, the hinge device has a hinge pin that extends into a socket located in an adjacent section so that both sections are supported by the hinge. In addition, each two sections are interconnected by a shear key protruding from one section into the same socket of the adjacent section.

Abstract: A boat outfitted with three hydrofoils disposed, e.g. in a triangular array. At least one of the hydrofoils are provided with an elevator, and the hydrofoils are spaced from the hull by supports therefor. The hydrofoils define the lowermost periphery of the boat and have a flat or substantially flat lower surface so that the boat can be beached on the hydrofoils.