Abstract: Flow modifying devices are simultaneously operative on the upper and lower surfaces of a fixed stabilizer foil on the submerged pod or hull of an ocean vessel to modify the lift hydrodynamically induced under control of pivotal flaps during propulsion of the vessel. The lift otherwise induced by the pivotal flaps is directionally reversed for all angular positions thereof by the spoiler devices.

Abstract: A propeller guard assembly for water craft that, in cooperation with a rotating propeller, creates a substantial increase in propulsive thrust and provides improved all around shielding of the latest state of the art propeller configurations. The increase in propulsive thrust of the propeller guard assembly of the invention is created primarily by the angle of the attack and hydrofoil cross section of the four guard rings or cowlings of the device. A secondary reason for the increase in propulsive thrust of the propeller guard assembly of the invention resides in the fact that the thrust realized is equal to the ratio between the effective projected propeller area and the area of trailing edges of the large primary and secondary guard rings which decreases the tendency of the propeller race to spread, particularly at high propeller slip during acceleration and take off.

Abstract: A hydrofoil device is useable as a hydrofoil wing, propeller blade, etc. In a water flow, a relatively lower pressure is generated on a second surface (94) of the device compared with a first surface (96). Near the trailing end of the first surface a protrusion in the form of an adjustable interceptor (98) is provided. The face of this protrusion defines an included angle to the upstream direction of less than or equal to 90° so that water flow thereat is deflected back on itself thereby increasing the local pressure on the first surface. A second protrusion may be provided near the leading edge of the second surface (94) to encourage flow separation thereat. Air may be provided adjacent each protrusion to provide natural ventilation if the pressure of the water flow drops below atmospheric pressure.

Abstract: A water sport device for supporting a seated human rider while the rider and the device are towed behind a powered water craft, including an elongate board to which a seat and foot holder are secured, an elongate hydrofoil extending downward from the board and a planing blade secured to the hydrofoil generally parallel to the board so that the planing blade provides essentially no lift when the board is horizontal.

Abstract: A high speed hybrid marine vessel with integrated hydrodynamic lift-generating, roll stabilizing and pitch controlling wings, or hydrofoils, operable in two distinctly different modes, namely a hydrostatic stable low speed mode, featuring a positive GM-value with at least three submerged hull elements; and a hydrostatic unstable high speed mode, featuring a negative GM-value with only one submerged hull element, the hull elements being integrated to the vessel via an integrated deck construction connecting the side hulls to the main hull.

Abstract: A method of controlling the attitude of a boat at high speed through boat hull design involves a first step of forming a pair of high speed steps in the hull of the boat. The pair of high speed steps provide enough surface area to control ride attitude, while reducing the wetted area of the hull to decrease drag. A second step involves forming transition steps to provide a transition to the high speed steps as the boat accelerates. In addition to reducing drag, the method aids in turning and lifting of the hull by trapping air and water in the steps.

Abstract: An inflatable boat adapted to serve as a training aid and enable a towable personal hydrofoil watersport device adapted to carry a seated rider having an elongate board and a vertical strut extending generally at a right angle to said board to float on the surface of the water comprising: (a) elongated spaced apart inflatable pontoon sections connected in proximity to their lower extremities by (b) a carrying surface, said pontoon sections and carrying surface forming a generally smooth leading surface for being towed through water with minimum drag, said carrying surface being provided with an opening in proximity to its trailing edge, said opening being adapted to retain said boat and the lateral distance between said pontoon sections being adapted to receive the elongated board of a water sport device adapted to carry a seated rider.

Abstract: The invention features a hydrofoil device for reducing wake formation on a partially immersed hull of a sailing or motor vessel.

Abstract: A method of controlling the attitude of a boat at high speed through boat hull design involves a first step of forming a pair of high speed steps in the hull of the boat. The pair of high speed steps provide enough surface area to control ride attitude, while reducing the wetted area of the hull to decrease drag. A second step involves forming transition steps to provide a transition to the high speed steps as the boat accelerates. In addition to reducing drag, the method aids in turning and lifting of the hull by trapping air and water in the steps.

Abstract: The improved flying ski is designed to be towed behind a conventional powered watercraft utilizing a standard ski tow rope or similar device having a handle that can be held by a human rider. In use, the rider is seated on the seat of the flying ski and towed by the watercraft. The improved flying ski comprises an elongate board and a seat that extends generally perpendicular to and upward from the board to support the seated rider's buttocks. The rider's legs extend toward the front of the board and are secured by a pair of foot holders that attach to the board. An elongate strut extends generally perpendicular to and downward from the board and couples the seat to a planing blade. The planing blade advantageously has a front blade and a rear blade interconnected by a fuselage. The improved flying ski accommodates a variety of rider skill levels by incorporating a mechanism and system that allows the rider to selectively adjust performance characteristics of the ski.

Abstract: The improved flying ski is designed to be towed behind a conventional powered watercraft utilizing a standard ski tow rope or similar device having a handle that can be held by a human rider. In use, the rider is seated on the seat of the flying ski and towed by the watercraft. The improved flying ski comprises an elongate board and a seat that extends generally perpendicular to and upward from the board to support the seated rider's buttocks. The rider's legs extend toward the front of the board and are secured by a pair of foot holders that attach to the board. An elongate strut extends generally perpendicular to and downward from the board and couples the seat to a planing blade. The planing blade advantageously has a front blade and a rear blade interconnected by a fuselage. The improved flying ski accommodates a variety of rider skill levels by incorporating a mechanism and system that allows the rider to selectively adjust performance characteristics of the ski.

Abstract: Low drag underwater submerged displacement hulls which can be used as independent vessels or as underwater displacement hull portions of a vessel whose main hull is at sea level are disclosed which have improved lift to drag ratios. The disclosed vessels have outer surfaces whose shapes are defined in plan and elevation by generally parabolic curves.

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 helical turbine assembly capable of providing high speed unidirectional rotation under a multidirectional ultra low-head fluid flow is disclosed. The assembly comprises an array of helical turbine units or modules arranged, vertically or horizontally, to harness, for example, water or wind power. Each turbine unit or module comprises a plurality of helical blades having an airfoil profile. The modules for wind power may be mounted to rotatable shafts supported by lightweight structures anchored by guy wires to the ground. The helical turbine can also provide ship propulsion by utilizing the power of ocean waves. In a further embodiment, a cylindrical distributor is provided in the helical turbine to channel the fluid flow to the blades of the turbine, thereby increasing efficiency and power output. The helical turbine with distributor may be used to lift or lower a body either being submerged into a fast stream or dragged in the fluid.

Abstract: The improved flying ski is designed to be towed behind a conventional powered watercraft utilizing a standard ski tow rope or similar device having a handle that can be held by a human rider. In use, the rider is seated on the seat of the flying ski and towed by the watercraft. The improved flying ski comprises an elongate board and a seat that extends generally perpendicular to and upward from the board to support the seated rider's buttocks. The rider's legs extend toward the front of the board and are secured by a pair of foot holders that attach to the board. An elongate strut extends generally perpendicular to and downward from the board and couples the seat to a planing blade. The planing blade advantageously has a front blade and a rear blade interconnected by a fuselage. The improved flying ski accommodates a variety of rider skill levels by incorporating a mechanism and system that allows the rider to selectively adjust performance characteristics of the ski.

Abstract: A hulls' shape of which cross-section is a section of a circle, thus retaining symmetry of its wetted surface (9) regardless of its rolling motion or heeling while under way. Shape that results in reduced weather helm effect, and more course stability on sailboats, as well as very low water resistance on vessels in general.

Abstract: A helical turbine assembly capable of providing high speed unidirectional rotation under a multidirectional ultra low-head fluid flow is disclosed. The assembly comprises an array of helical turbine units or modules arranged, vertically or horizontally, to harness, for example, water or wind power. Each turbine unit or module comprises a plurality of helical blades having an airfoil profile. The modules for wind power may be mounted to rotatable shafts supported by lightweight structures anchored by guy wires to the ground. The helical turbine can also provide ship propulsion by utilizing the power of ocean waves. In a further embodiment, a cylindrical distributor is provided in the helical turbine to channel the fluid flow to the blades of the turbine, thereby increasing efficiency and power output. The helical turbine with distributor may be used to lift or lower a body either being submerged into a fast stream or dragged in the fluid.

Abstract: The present invention relates to a boat-activated wake enhancement method and system that extends from the boat. According to one aspect, a pair of protuberances is provided on the lower stem quarter of the boat's hull, primarily along the sidewalls. The protuberances are elongated and each has a rounded surface that extends substantially laterally outward in relation to the boat hull. The protuberances help to displace more water by increasing and shifting the effective width of the boat, causing the boat to travel deeper in the water, and creating additional interference that affects the natural wakes created by the boat. Additional inverted hydrofoil members and ballasts can also be provided to cause the boat to travel deeper in the water and therefore create larger waves. The present invention is used to increase the size and enhance the shape and location of the wake and/or waves for wakeboarding and wake surfing.

Abstract: Cavitation of a hydrofoil element, such as the rudder of a marine vessel, om exposure to a body of water during onset flow at different angles to the chordal axis of the rudder profile, is suppressed by a tab on the lower end tip of the rudder. Such tab has external surfaces thereon which affect flow separation relative to the rudder so as to suppress or delay cavitation.

Abstract: A water vehicle includes at least first and second foils which are at least partially submersible in water. These foils are movable, at least to a limited extent relative to each other. Repeated movement of the foils generates a propelling force that will move the water vehicle on the body of water.

Abstract: A hydrofoil marine vehicle having separate forward and rearward hydrofoil wings connected by a center beam. The generally V-shaped hydrofoil wings are affixed to the center beam at either end by means of flexibly mounted struts. The center beam supports a passenger cabin or pod which may also include a gyroscopic element. In one embodiment of the marine vehicle, the pod, which is hydraulically suspended above the center beam, houses a gyroscope which is approximately 4-10 feet in diameter and weighs about 100-500 pounds. The gyroscope acts as a pod stabilizer and energy absorbing mechanism. Static flotation for the marine vehicle is provided by the passenger pod. At slow forward speeds, the hydrofoils are submerged and the upper curved surfaces of the hydrofoils generate the lift required to bring the hydrofoils to the surface of the water.

Abstract: An aircraft-like body is provided with a keel that extends below and to the rear of the main body. The keel is provided with a large horizontally extending hydrofoil which produces a positive lift. The keel is further provided with a smaller hydrofoil which is located aft of and below the positive life hydrofoil and which produces a negative lift. The negative lift hydrofoil is located both aft of and below that which produces the positive lift. The downward force which is produced by the trailing hydrofoil produces a cranking action which produces a moment and applies a lifting force which, as the vehicle proceeds through the water, lifts the nose of the vehicle and impart an aircraft lift-like flying type of sensation to the operator.

Abstract: A catamaran-type boat having two or more demi-hulls that are connected by a wing-shaped superstructure is disclosed. The demi-hulls are further connected by two or more transverse hydrofoils. A tunnel is created between the demi-hulls and the superstructure. The shape of the superstructure takes advantage of the airflow through the tunnel to provide aerodynamic lift. The hydrofoils serve two purposes. The first is to provide hydrodynamic lift, and the second is to cancel wave build up between the hulls. The wave cancellation assists the stability of the craft by providing a relatively flat surface for the wing, to provide stable additional lift through the "wing in ground" effect. The combination of hydrodynamic lift, wave cancellation, and aerodynamic lift decreases the ship's drag and increases its speed.

Abstract: The invention permits and promotes high speed water towing by uniquely immenting hydrofoil technology in association with a trailer vehicle. According to many inventive embodiments, a hydrofoil component (comprising one or more foils) is placed in the aft half region of the trailer vehicle; however, the front half region of the trailer vehicle is devoid of hydrofoil structure. The trailer vehicle is adaptable to a semi-rigidly towably connective relationship with a tractor vehicle. When the trailer vehicle is towed by the tractor vehicle at design speeds, most of the weight of the trailer vehicle is supported by the hydrofoil component, while the remaining weight is supported by the tractor vehicle. The invention avails benefits of hydrofoil use, but averts or allays difficulties which are customarily encountered with hydrofoil use.

Abstract: The present invention relates to a hydrofoil system of a sailing-trimaran having a central hull and two outriggers. Inclined, retractable foils are placed in a head of each outrigger, forward of the center of area of a sail and from the center of gravity of the trimaran. Two additional hydrofoils are arranged each on the stern of an outrigger so that each is clear of the water if the side wind pressure effecting the sail is low. A third additional hydrofoil is arranged on a rudder in the stern of the central hull.

Abstract: A sloped hydrofoil (22) is mounted to the bottom of a sailboard or surfboard vertical strut (26) using a hinge joint (24). Hinge joint (24) allows reversal of the slope of sloped hydrofoil (22) in response to a hull (30) side slip. Efficient sloped hydrofoil (22) supports a portion of craft weight to reduce hull (30) drag.

Abstract: A preferred planing foil apparatus (10) for use with a pontoon boat (12) includes mounting structure (32) for connecting a planing foil (30) to the boat (12) with the foil (30) positioned between and spaced from the pontoons (12, 14) generally amidships and straddling the transverse centerline of the boat (12). The foil (30) is also positioned between the waterline (62) and the lower surfaces (64) of the pontoons (12, 14) when the boat (12) is at rest so that foil (30) rises toward a planing position on the surface of the water as the boat (12) is propelled therealong in order to lift the boat (12) and reduce drag.

Abstract: A wake control apparatus for adjusting the trim of a watercraft to selectively raise and lower the level of the wake produced by the watercraft. The apparatus comprises a pair of hydrofoils which are pivotally connectable to the watercraft in spaced relation to each other. Mechanically coupled to respective ones of the hydrofoils is a pair of actuators which are connectable to the watercraft. Each of the actuators is operative to pivotally move a respective one of the hydrofoils between neutral, first and second positions. The apparatus is attachable to the watercraft such that each of the hydrofoils is moveable by a respective one of the actuators about an axis which extends in non-perpendicular relation to the longitudinal axis of the watercraft.

Abstract: A hydrofoil propeller guard, including a thrust tube, a hydrofoil fin and bottom securing plate, is used in conjunction with an outboard motor mounted on a boat and with stern drives, to encompass the propeller to reduce sideways thrust, to move items away from the propeller, and the guard preferably includes a trolling plate to increase slow speed performance.

Abstract: A wake reflector system attached to the hull of a surface or subsurface vessel attenuates the visible surface elements of a vessel's displacement wake, making the vessel less likely to be detected by passive observation means from above. The system consists of plates firmly mounted parallel to the longitudinal axis of the hull over a sufficient length and at a sufficient distance outboard from the hull to contain and affect at least the bow component of the displacement wake. The system may incorporate non-reflective means to leak or pass a calibrated portion of the wake energy through the reflector system along its length. When the vessel moves forward, the displacement wake travels to the plate system and is contained and reflected back and forth between the plate system and the hull over the length of the system, substantially attenuating the peak amplitude, integrity and outward momentum of the remaining wake. The system is applicable to both surface vessels and submarines.

Abstract: The present invention is primarily a boat activated wave generator that can be operated in a deep body of water. The wave generator is pulled or otherwise pushed through the water, and has wave generating portions that scoop up water, to form wave shapes thereon, upon which various surfing and skimming maneuvers can be performed. The shape of the wave generator is such that it forms wave shapes, and various wave formations, and remains in substantial equilibrium in the water. The wave generator also forms wakes, and enhances the boat's wake, such that various skimming maneuvers, i.e., wake-boarding and water skiing can be performed.

Abstract: The novel sailboard is arcuate about its longitudinal and transverse axes, and has blading fore and aft for supporting the sailboard upon a frozen surface. The front blading is carried on a pivotal plate which has spring loading and damping, and the rear blading comprises pluralities of blades of varying height and attitude relative to the longitudinal axis.

Abstract: A wake control apparatus for adjusting the trim of a watercraft to selectively raise and lower the level of the wake produced by the watercraft. The apparatus comprises at least one hydrofoil which is pivotally connectable to the watercraft, and at least one actuator which is mechanically coupled to the hydrofoil and connectable to the watercraft. The actuator is adapted to selectively move the hydrofoil between first and second positions. When the apparatus is connected to the watercraft and the watercraft is propelled within the water, the movement of the hydrofoil toward the second position causes the aft end of the watercraft to be drawn downwardly into the water to increase the level of the wake produced thereby. The movement of the hydrofoil toward the first position causes the aft end of the watercraft to be elevated within the water to reduce the level of the wake produced thereby.

Abstract: The ferry boat has a rectangular main deck with superstructure above and hull structure below. The superstructure is essentially rectangular in all views and has one or more decks with a plurality of traffic lanes on each deck in addition to those on the main decks with optional passenger carrying compartments. The lanes are straight and parallel and there are no deck-to deck ramps. The hull structure has two sidewalls, one along each of the long sides of the main deck and two skirts, one at each end of the main deck. The skirts extend between the sidewalls and have vertical aft surfaces and front surfaces which slope downward and aft. The lower extremities of the sidewalls are further from the main deck than the apexes of the skirts. The volume enclosed by the sidewalls, skirts, main deck and water surface is filled with entrapped air which will compress to provide a major part of the support of the boat. There are two hydrofoils, one forward, one aft and extending between the sidewalls.

Abstract: A hydrofoil stabilizer for a marine motor includes a hydrofoil wing having a generally planar configuration and a shroud member affixed to an underside of the hydrofoil wing. The shroud member has a generally tubular configuration so as to extend around an exterior of the propeller of the marine motor. The hydrofoil wing is affixed to an underside of the anti-cavitation plate of the marine motor. The hydrofoil wing has a first edge with a notch formed therein so as to receive a portion of the marine motor. A forward edge of the hydrofoil wing has inwardly curved forward edges on opposite sides of the notch. The shroud member is affixed to the hydrofoil wing such that a central axis of the shroud member extends at an angle of between 50.degree. and 20.degree. relative to the plane of the hydrofoil wing.

Abstract: In order to improve the trim of a power boat ready to accelerate toward "on plane" speed, a deflector plate is deployed by gravity from a substantially horizontal attitude toward a rearward-downward inclination, the deployed plate being located so that a predetermined portion only of the propeller backwash is intercepted. Latching mechanism locks the deflector plate at an optimum angle of deployment until the boat reaches a speed slightly in excess of "planing" speed at which juncture the deflector plate is unlocked by remote control, either automatically or manually. The device can be used either for outboard motor or stern drive propulsion units.

Abstract: A sloped hydrofoil (22) is mounted to the bottom of a sailboard or surfboard vertical strut (26) using a hinge joint (24). Hinge joint (24) allows reversal of sloped hydrofoil (22) slope in response to a hull (30) side slip. Efficient sloped hydrofoil (22) supports a portion of craft weight to reduce hull (30) drag.

Abstract: A high speed ship is disclosed which includes a hull structure having a bow portion and a stern portion with the hull being normally supported above the surface of the water when in operation. A forward strut depend from the bow portion of the hull structure and is subtended by a first transverse displacement foil. A set of midship dual struts depend from the hull structure aft of the forward strut; the aft dual struts are subtended by a second transverse displacement foil extending laterally between and connected to each of said struts. The second transverse displacement foil has a beam equal to or greater than its length and provides 70% or more of the major buoyancy for the ship during operation to maintain the hull above the surface of the water during operation. The forward foil provides less than 30% of the buoyancy of the vessel and has a beam less than the spacing between the aft struts.

Abstract: A small water plane area twin hull (SWATH) ship (10) has two demi-hulls (11), a strut (12) mounted to each hull which extends to a cross structure (14) spanning the struts. A buoyant foil (18) extends between the two hulls.

Abstract: A self-propelled water craft includes a hydrofoil-bladed wheel assembly which allows an individual to propel the water craft through the water at a relatively high speed. The assembly comprises an open frame with attachment means for securing to a stern of the water craft's boat hull, a drive shaft rotatably mounted on the open frame, at least one bladed wheel permanently secured to the shaft to rotate with the shaft, and a hydrofoil mounted on the open frame directly below the bladed wheel. The blades are mounted on the periphery of each wheel and are angled backwardly. The blades are also curved. As the blades move through water they force water flow over the hydrofoil in a manner which propels the water craft forwardly and provides the proper lift to the water craft so as to lessen water resistance against the boat hull.

Abstract: A proa sailing vessel has spaced hulls each having underwater shapes which are substantially symmetrical about a central athwartship axis and a mast which may be pivoted between forwardly inclined attitudes relative to the respective ends of the vessel. The sail is in the form of an isosceles triangle which is set to leeward of the mast whereby either opposed edge may be selectively tensioned between the forwardly inclined mast and the front end of the vessel. The mast extends upwardly from the leeward side of the main hull and is inclined to leeward to assist in self-righting or the vessel.

Abstract: Hinge apparatus which includes first and second hinge members (12, 14) arranged for relative rotation about a hinge axis (18), and fluidic actuator apparatus (24). The fluidic actuator apparatus includes a force transfer member (22) having a first end attached to the first hinge member at an anchor location spaced from the hinge axis, and expandable pillow (25) apparatus associated with the force transfer member and operative to expand when exposed to a fluidic pressure thereby to apply a force along the force transfer member to the first hinge member so as to cause rotation of the first hinge member relative to the second hinge member in at least a first direction.

Abstract: A wind-propelled hydrofoil comprising a forward assembly with at least partially submerged forward foils and a fully submerged aft foil. The forward foils (43, 44) are such that the resultant of the vertical forces drops when said assembly is translated vertically upwards, with a heave characteristic (F), and increases when said forward assembly is subject to upward pitching, with an incidence characteristic (A). The aft foil (46) has an incidence characteristic (R) such that R(d-g)-Ag+F(g.sup.2 +r.sup.2)>0, wherein d is the distance between the aft foil (46) and the center of heave, g is the distance between the center of gravity and the center of heave, and r is the gyration radius of the hydrofoil.

Abstract: A hydrofoil wing structure is disclosed to be employed as an accessory for a marine propulsion device, to be disposed above and mostly aft of the propelling means of such a device, to contour and concentrate the kinetic energy in the hydrodynamic vortex created by the propelling means; to reduce turbulence, vibration and noise by reflecting acoustic energy downwardly from the surface of the water; to increase the efficiency of such a device powered by an electric battery; to improve the steering and maneuverability of the vessel by providing a rudder for the device; and to serve as a guard preventing the propelling means from entanglement in vegetation or its damage from submerged objects, and to similarly shield a sonar transducer or other instrument used in conjunction with the device for finding fish or gauging the depth of the water.

Abstract: An agile water vehicle for travel above and below the water surface, incls a hull having therein a helmsman's compartment, a payload compartment, and a propulsor unit. A rudder assembly is fixed to the hull and includes a cylindrically-shaped (or slightly tapered) tubular member having a rudder thereon and extending therefrom, the tubular member being rotatable. A wing assembly is fixed to and spaced from a bottom portion of the hull, the wing assembly comprising a pair of wings extending widthwise of the axis of the hull, and a flap adapted for disposal in each of the wings and extendible therefrom, the flaps being operable for pivotal movement upwardly and downwardly from the wings. The propulsor unit, the rudder assembly, and the flaps are operable from the helmsman's compartment. A pair of propulsors are disposed on the wings and are rotatable around the spanwise axis of the wings. A pair of differential flaps are mounted on a rotatable axial cylinder or ring with a fixed divider plate therebetween.

Abstract: A high-speed hydrofoil craft has a hull supported by a foil. When the foil is submerged, the upper surface of the foil may be ventilated by atmospheric air to form an air-filled cavity, in which case the foil performs similarly to a planing foil.

Abstract: Disclosed is a construction applicable to stern drive and outboard types of power boat propulsion units for enhancing the performance normally provided by the customary trim/tilt capabilities designed into the units. At a critical juncture in the trim/tilt operation, the present device automatically "kicks in" and by intercepting only a predetermined portion of the propeller backwash provides an almost immediate stern up/bow down result without noticeable speed retardation. The device lends itself either to kit form or to factory installation.

Abstract: A high speed ship is disclosed which includes a hull structure having a bow portion and a stern portion with the hull being normally supported above the surface of the water when in operation. A forward strut depends from the bow portion of the hull structure and is subtended by a first transverse displacement foil. A pair of midship struts depend from the hull structure aft of the forward strut; the aft struts are subtended by a second transverse displacement foil extending laterally between and connected to each of said struts. The second transverse displacement foil has a beam equal to or greater than its length and provides 70% or more of the major buoyancy for the ship during operation to maintain the hull above the surface of the water during operation. The forward foil provides less than 30% of the buoyancy of the vessel and has a beam less than the spacing between the aft struts.

Abstract: A method and an assembly are provided for mounting a pair of hydrofoils to an outboard engine without drilling holes or otherwise defacing the anticavitation plate of the engine. The assembly includes a mounting plate, an adaptor, and a pair of hydrofoils. The hydrofoils are mountable to the outer edge portions of the mounting plate. In use, the counter-rotation tab of the engine is removed and then replaced by the adaptor. The mounting plate, if not already secured to the adaptor, is coupled to the adaptor. The hydrofoils are then mounted to the opposing edges of the mounting plate. A pair of reinforcing brackets may be secured to the mounting plate such that they extend over the edge portions of the cavitation plate. The forces generated upon the mounting plate will accordingly be distributed to the anti-cavitation plate as well as the adaptor. The hydrofoils employed in the assembly preferably include rudders, which obviate the need for the counter-rotation tab replaced by the adaptor.

Abstract: A watercraft comprises a hull having an upper surface, a lower surface, a bow and a stern. Spaced from the underside of the watercraft at the bow end is a pair of outwardly extending arms rotatably supporting discs. Likewise at the stern of the hull, a pair of arms rotatably supports an additional pair of discs. A multitude of such discs may additionally be provided with bearings. Alternatively, the discs may be mounted upon a ball joint arrangement for rotation and pivoting throughout a preselected range. Each disc is acutely angled from a horizontal reference plane. When the watercraft moves in a forward direction, the discs will rotate. As a result, the relative contact velocity between an underside portion of the discs and the water is substantially reduced as compared to a surface which is fixed to the watercraft. The contact friction is thereby reduced resulting in high speed capabilities of the craft with relatively low powered propulsion units.