Abstract: An improved sailboard (10) including a hull (12) with a fin (20) secured at the rear thereof, a flexible skirt (24) secured to the hull (12) and extending aft of the fin (20), and a rear extension (29) of the hull that extends aft of the skirt (24). The tail edge (16) of the hull (12) wraps around fin (20) and is cut forward so that the skirt (24) extends laterally of the fin (20).

Abstract: A fin assembly for mounting to a lower surface of a watercraft hull comprises a base for attachment in a fixed position to a watercraft hull lower surface, the base having first hinge pin receiving bores defining a hinge axis, a fin having an inner end having second pin receiving bores for pivotally securing to the base for pivoting about the hinge axis, and a hinge pin mounted in the first and the second hinge receiving means pivotally connecting the fin to the base, and an elastomeric member disposed between the base and the fin for resisting pivotal movement of the fin relative to the base

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: Lightweight, high-strength flotation devices such as surfboards, sailboard and body boards that can be inexpensively manufactured from plastic sheet materials using thermo-vacuum forming techniques. The devices include specially configured structural cores which provide strength and rigidity to the devices. The structural cores are, in turn, encapsulated between specially configured upper- and lower-shaped panels which add strength to the devices and create a sleek, finished appearance.

Abstract: A sailboard or surfboard (30) having a fin (32) and a skirt (36) extending aft of the tail edge (34) of the board. The skirt (36) is mounted to the sailboard in a manner so that the skirt assumes the contour of the water when sailed. Adhesive or a clamp plate is utilized to secure the skirt (36) to the board (30). The fin (32) includes a fin base (60) and a foil (62). Foil (62) is positioned aft of the fin base (60) so that the trailing edge (64) of the foil (62) is aft of the fin base (60).

Abstract: A system for attaching fins (11) to surfboards and other surf craft utilizes fixing elements (12) embedded in the body of the board, these elements having slots (13) which receive tabs (18) extending from the end of the fin. The tabs are removably secured by grub screws (16) enabling fins to be removed for transport or upon damage.

Abstract: A watercraft hull having a lower surface for normal contact with a body of water includes a fin having an inner end secured to the lower surface for extending into a body of water, a hinge intermediate the inner and outer ends for enabling an outer portion of the fin to pivot about the longitudinal axis of the watercraft for enabling increased controllability and performance of the watercraft.

Abstract: A pivotable fin system, for use with an aquafoil such as a surfboard, comprising a plug and a fin having a main portion and a tab. The plug mounts in the surfboard, and has a central slot for receiving the tab. The tab has a reverse taper that matches a reverse taper in the central slot. The tab has at least one vertical slot which compresses to allow the tab to be mounted in the central slot, the vertical slot expanding once the tab is fully inserted into the central slot, the tab then securely held in place by the matching reverse tapers of central slot and tab. The tab has at least one tab cut for allowing the main portion of the fin to pivot with respect to the tab, allowing the main portion of the fin to self-align to a position where it reduces drag and cavitation.

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 quick change fin assembly for attachment to a buoyant test vehicle (BTV). he fin assembly comprises a fin body bolted to a T-shaped base portion. A resilient sheet is placed between the fin body and the base to lessen the transmission of vibrations from the fin body to the base. The assembly is attached to the truncated cone surface of the tail portion of the BTV. For each fin, a longitudinal T-shaped slot is cut into the surface of the tail portion starting from the truncated end and extending along the axis of the BTV. The T-shaped base slides into the slot from the truncated end to secure the fin assembly in a radial direction with respect to the axis of the BTV. A conical end piece is threaded onto the tail portion to clamp the fin assembly in an axial direction. The exposed surface of the T-shaped base is shaped to conform to the tail portion and to provide a smooth transition between the tail portion and the fin body.

Abstract: A water ski having an elongated body of generally uniform thickness from its nose to its aft end, and including a body having a nose portion which inclines gradually upwardly, a forward body portion, and a rear body portion. The forward body portion has a width which is generally uniform and which is like that of a conventional water ski. The rear body portion extends rearwardly from the forward body portion and has side edges which diverge outwardly and rearwardly toward the rear end of the ski, with the width of the ski at its rear end being at least 150% of the width of the forward body portion. The longitudinal length of the rear body portion is from 25 to 75% of the length of the ski.

Abstract: One or more variable angle fin box assemblies are sealed on the underside of a surfboard or the like that allows the angle of attack of the fin to be varied with the respect to the longitudinal axis of the surfboard, enabling the speed, stability and maneuvering characteristics of the surfboard to be adjusted or "tuned" by the rider in accordance with the rider's level of skill, different surf conditions and wave sizes. The novel fin box assembly has a longitudinal channel to receive the base end of a conventional surfboard fin, and in which a device is provided for securing the movable fin in the selected adjusted angular position.

Abstract: A device for towing a swimmer behind a boat. The inventive device includes a planar member having a line anchor coupled thereto for securing to a tow line extending behind a boat. Handle apertures are directed through the planar member for engaging hands of a swimmer and a steering fin extends from a bottom surface of the planar member such that the swimmer can articulate the planar member to steer and dive within the water while being towed behind the boat.

Abstract: A water ski adjustable fin block and fin are disclosed. The fin block employs a slidable wedge for clamping the fin in place within the fin block during use and allowing the fin to be unclamped just enough to allow adjustment of the fin. A screw arrangement is used to move the wedge. The adjusters allow the leading edge and trailing edge of the fin to be adjusted as to vertical relationship with the water ski. A third adjuster allows the fin to be move longitudinally toward the front or back of the ski. The adjusters provide captive treatment of the fin preventing the fin from excessive movement, or even falling out, while adjustment is performed. The present invention allows a water skier to easily adjust the fin using an allen key or the like.

Abstract: A watercraft containing a fin box system, said fin box system comprising a chamber of spaced side walls and end walls, and a fin with a fin base that can travel vertically, horizontally or at an angle within said chamber; said chamber is fixed within said watercraft, and said fin base having a device to expand and contract itself against said side walls or end walls can be releasably fixed at an infinite number of positions within said fin box.

Abstract: A control surface for a vehicle comprising a flexible elastomeric body with ts base joined to the vehicle to form a smooth surface, a rigid tip bar joined to the distal end of the body, and a control member for turning the rigid tip bar to bend the elastomeric body and generate lift. The control member can be a shaft which extends from the interior of the vehicle to said rigid tip bar to allow said shaft to rotate said tip bar.

Abstract: An underwater maneuvering device is disclosed. The device consists of a base member and a pair of perpendicularly disposed fins. A hand grip on the base member provides vertical and horizontal directional control. Hand grips on the fins provide also vertical and horizontal directional control. The device can be disassembled for easy storage and transport.

Abstract: A flexible fin for surfboards, sailboards and other watercraft comprises a thin core sheet made of laminated fiberglass sandwiched between two slabs of closed-cell polyurethane foam. The flexible fin provides for sharper turns while increasing the buoyancy of the craft.

Abstract: A system for attaching fins (11) to surfboards and other surf craft utilizes fixing elements (12) embedded in the body of the board, these elements having slots (13) which receive tabs (18) extending from the end of the fin. The tabs are removably secured by grub screws (16) enabling fins to be removed for transport or upon damage.

Abstract: A pullable, steerable watercraft is operable to be towed behind a power boat of kite. The watercraft has a steering mechanism within the watercraft body, and has a dome-shaped steering control recessed into the top surface thereof. The steering mechanism includes a movable mechanical shaft or arm which extends through the interior of the watercraft and which pivots about a vertical axis in order to rotate a rudder.

Abstract: An aerodynamic vane is mounted on the fuselage of an aircraft for purposes such as sensing the angle of attack of an aircraft. The vane is attached to a fuselage mounting hub by means of a deformable hinge member and a weakened linear portion of the vane which is designed to give way under the force of impact of an object striking the vane. Should an object such as a bird strike the vane, the vane will separate from the hub along the weakened linear portion without the main body of the vane shattering. The hinge member, while it will deform under the impact, retains the vane to the fuselage so that it cannot fly into the engine or otherwise cause damage to the aircraft.

Abstract: A body surfing board includes a flexible hull having a lower surface, an upper surface adapted to receive a swimmer, and a nose section defining a forward end of the hull. A tail section including a keel extends downwardly from the lower surface of the hull. A pair of fins extend downwardly from the hull along opposite lateral edges thereof. The fins are each pivotable along their respective attachment to the hull, inwardly and outwardly with respect to one another. A plurality of slits extend between the pair of fins for translating the force of a water wave into forward movement of the body surfing board. In one embodiment, a plurality of ribs fixed to the lower surface of the hull define the slits. In another embodiment, a plurality of ribs are positioned within the nose section of the hull to open and close the slits in response to movement of the fins. In still another embodiment, the slits are incorporated into a diaphragm member.

Abstract: A water ski fin extends through the rear of a water ski. Pivotally connected to a lower portion of the fin is a wing extending substantially perpendicularly from the fin. A device is connected to the wing that allows the wing to pivot and change its angle of attack as a function of the speed of the fin through the water.

Abstract: A mast box for a sailboard is embedded in the sailboard. The mast box has a T-shaped groove for clamping a mast foot to the sailboard, a pin for holding a leash rope, and a vent for venting pressure from the core of the sailboard. The vent may include a one way valve.

Abstract: A long and slender box shaped fin holder, that provides a pinned connection between the fin and the holder box. The pinned connection is located within the box itself, so as to allow rotational capabilities, while also offering lateral stability to the fin from the sides of the holder box. The rotational freedom of the fin is regulated by a spring type device attached to the leading edge of the fin and at the same time, to the forward wall of the holder box. The holder box is also equipped with a latch type device to facilitate locking the fin in a fully retracted position, which primarily conceals the fin within the holder box. This holder box is embedded within the top and the bottom surfaces of a typical surfboard, kneeboard, or windboard, typically near the rear of the board.

Abstract: A water ski fin extends through the rear of a water ski. Pivotally connected to a lower portion of the fin is a wing extending substantially perpendicularly from the fin. A linkage is connected to the wing that permits the wing from pivoting until the speed of the fin through the water exceeds a predetermined velocity to pivot and change its angle of attack in response to the speed of the fin through the water exceeding the predetermined velocity.

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 system for attaching fins (11) to surfboards and other surf craft utilizes fixing elements (12) embedded in the body of the board, these elements having slots (13) which receive tabs (18) extending from the end of the fin. The tabs are removably secured by grub screws (16) enabling fins to be removed for transport or upon damage.

Abstract: A body board for wave surfing includes a shark-shaped semi-rigid board having a pair of depending pectoral fins. The underside of the board is concave, and the board has a cone-shaped nose section with an underside including a series of laterally inboard projecting slats which open and close in response to movement of the fins. A tail section stabilizes the board in the water and provides a seat for the surfer while waiting for or traveling to a wave. The fins each include a sleeve adapted to receive the surfer's hands.

Abstract: A surfboard fin intermediate ha a rigid body element with flexible material (e.g. rubber) covering the leading and trailing edges, with a protective material--such as aluminum foil tape--readily removably secured to the flexible material on a small part of the body element to substantially completely cover the flexible material to protect it during manufacture of a surfboard with the fin attached, such as during sanding. The fin with protective material is placed so that the base engages the bottom of a surfboard, resin impregnated fiberglass rope or roving is applied to the base of the fin and the surfboard bottom spaced from the flexible material, and then resin impregnated fiberglass cloth is applied to the fin and bottom surface of the surfboard. After the resin dries, most of the fiberglass cloth exterior of the fin is cut away with a blade, and then any unwanted portions of the fiberglass cloth associated with the fin are sanded away. Then the protective material is removed from the fin, e.g.

Abstract: An improved water ski apparatus and method are disclosed. A slalom water ski having an adjustable rudder fin is configured such that the rudder fin can be selectively and precisely moved in vertical, horizontal and diagonal directions in a manner such that each movement parameter can be separated from the others and is precisely moveable to within thousandths of an inch accuracy, in calibrated manner. Means are provided to enable complete removal of the rudder fin from the ski, and subsequent replacement while exactly preserving the last adjusted mounting position of the fin relative to the ski. An improved fastening technique for mounting the rudder fin to the ski body without loosening or stripping of the fastening members is also disclosed, as well as a method for fabricating a ski body that integrally incorporates the improved fastening members in the body of the ski.

Abstract: A fin (1) for a windsurf board is constructed from fibers (5) which have a preferred fiber direction with the majority of the fibers lying in this direction, the preferred direction extending at an acute angle (a) to the longitudinal axis (4) of the profile of the fin blade (2). This allows the fin to distort and to change the properties of its profile in a defined manner when loaded.

Abstract: A surfboard has one or more (e.g. three) fins extending from its bottom surface. Each fin is a rigid plastic body element (e.g. Shore D hardness of at least about 78) with curved leading and trailing edges, a base, and side walls. The edges intersect in a rounded tip, and the leading edge curves back toward the rear of the surfboard. The leading and trailing edges, but not the sides, of the fin rigid bodies are covered with a soft flexible material (e.g Shore A hardness of about 40-100), such as rubber, urethane, or silicone. The flexible elastomeric material has sufficient thickness, softness, and flexibility to protect a surfer impacted by a leading or trailing edge of the fin, and to act as a rudder (provide anti-cavitation action) to provide some board steerability by the surfer shifting his or her weight.

Abstract: A ski board is arranged to include a polymeric skin envelope housing a foam core, to include a rear wall having a plurality of parallel troughs orthogonally intersecting the rear wall canted upwardly towards the top wall to receive the leg portions of an individual therewithin. A rudder control handle is mounted forwardly and in alignment with each trough between each trough and the forward wall of the ski board structure. A tow ring mounted medially of the rudders in adjacency to the forward wall is arranged to receive a tow rope for towing of the organization.

Abstract: A fin for water sports boards having a urethane leading edge cover molded in place onto an anchor flange having holes therethrough on the leading edge of the fin. The fin is of glass fiber reinforced resin.

Abstract: An essentially flat parallelogram-shaped locking nut with rotational biasing spring is disclosed as part of a locking device attached to a supporting tongue of a nautical fin for water craft, such as sailboards, where their hulls or keels either contain or may be modified to contain an elongated channeled mounting box with internally recessed lateral grooves for receiving said nut and thereby locking the fin to the hull.

Abstract: A lightweight, high strength, water ski hydrofoil assembly includes a diamond planform hydrofoil wing and a V-strut connecting the wing to a parallel ski support platform. The diamond planform wing is formed as a unit and the separately formed V-strut and platform secured thereto. The wing is provided with a foam plastic, aluminum or composite core element, while the V-strut and platform are provided with core elements selected from aluminum or aluminum alloys, composites and balsa wood. In the preferred embodiment, the core elements are provided with an intermediate layer of molded composite material (resin impregnated fiberglass and graphite fibers, or cloth) and an outer layer of rubber. The rubber coating may be applied to the core elements by injection molding, and confined to the leading and trailing edges of the components, with the intermediate layer being omitted, in some embodiments.

Abstract: The lip-type seal for the inlet opening (2) for the dagger board housing and the dagger board (3) exhibits two supporting strips (5) countersunk into the board hull (4) on both sides of the inlet opening (2) as well as two mounting strips (7) with a sealing lip (8) for clamping onto the supporting strips (5), these mounting strips terminating with the profile (6) of the underwater hull and being fashioned as clamping strips. The mounting strip (7) is designed as an L-profile. Respectively one short, perpendicularly bent-away clamping leg (11, 12) is formed at the end edges of the long (9) and of the short leg (10) of the mounting strip (7). The sealing lip (8) adjoining the long leg (9) of the mounting strip (7) is formed, on its longitudinal side facing away from the mounting strip, into a rounded sealing edge (13) passing over into an elastic supporting leg (14) that is oriented obliquely upwardly, this supporting leg being attached to the end edge of the short leg (10) of the mounting strip (7).

Abstract: The lip-type seal for the bottom closure of the inlet opening (2) for dagger board housing (3) and dagger board (4), intended for sailboards, exhibits two mounting strips (6) of a hard plastic with a sealing lip (7) of an elastic plastic, countersunk on both sides of the inlet opening into the board hull (1) and terminating with the profile (5) of the underwater hull. The mounting strip (6) is fashioned as a U-profile with an inner (8) and an outer, short leg (9), these legs being joined by a web (10) extending obliquely in correspondence with the profile (5) of the underwater hull. The sealing lip (7) adjoining the mounting web (10) of the mounting strip (6) has a rounded sealing edge (11) passing over into an elastic supporting leg (12) oriented obliquely upwardly, the supporting leg being attached to the outer leg (9) of the mounting strip (6). The mounting strip (6) is pressed or glued, with the inner leg (8), into a corresponding groove (14) in the board hull (1).

Abstract: The present invention relates to an apparatus designed to launch a sailboard out of the water while the sailboard is being sailed on the water. The apparatus comprises launching means including a flap which is submergible in the water and pivotally supported at one end of the flap near the bottom of the sailboard. An angle of attack of the flap relative to the water is varied by a positioning means. The submerged flap is thus presented at an oblique angle to the incompressible water which thus acts as a ramp to launch the sailboard out of the water. In an alternative embodiment, a hydrofoil wing acts to lift the sailboard relative to the water surface.

Abstract: A dagger board bearing for sailboards, developed with the objective of improving sailing properties, exhibits a dagger board casing (4) inserted in a sailboard (1) wherein a dagger board (5) introducible from above is pivotably supported with a first handle (6) projecting beyond the topside of the board (5). An external pivot pin (12) in the zone of the top edge (13) of the dagger board (5) and an internal pivot pin (14), offset with respect to the external pivot pin (12) are molded to a top section (11) of the dagger board (5). The pivot pins (12, 14) are arranged on one side of the top section (11) of the dagger board (5) with a mutual first spacing (a) in the longitudinal direction of the dagger board (5) and with a mutual second spacing (b) in the transverse direction of the dagger board (5).

Abstract: A fin box adapter for securing narrow based fins in cavity-type sailboard fin boxes comprising a generally trapezoidal block member having an outer surface configuration corresponding to an inner cavity surface configuration of a cavity fin box, and an inner slot-like cavity for receiving a bottom portion of a modified narrow fin base. In use, a narrow based fin is modified by trimming down any excessive length to fit the inner slot-like cavity and one or more press-fit cross-pins are used to secure the fin base within the inner slot-like cavity of the fin box adapter. A template is used to assist the installer in trimming down the fin base. The top surface of the fin box adapter is provided with one or more threaded holes which cooperate with the existing mounting hardware of the cavity fin box of the sailboard. In an alternate embodiment, a single threaded press-fitted cylindrical block is used in favor of the pins to secure the fin within the slot-like cavity.

Abstract: The assembly for fastening a fin to a sailboard comprises a fin receiving box secured in the sailboard and having an opening to receive a fin shaft. A conical or wedge seat is provided between the fin shaft and the opening in order to warrant a firm attachment of the fin.

Abstract: A multiple fin surfboard defines a generally elongated planar surfboard having a plurality of elongated slots defined therein. The slots are grouped close to each end of the surfboard and support a corresponding plurality of fins in a pivotal attachment. The fins each support transverse vanes which are acted upon by a water passage beneath the surfboard to alternatively retract the fins at one end of the surfboard and downwardly extend the fins at the opposite end of the surfboard.

Abstract: A wind propelled sailing apparatus having a sailboard hull adapted to support a user; a sail for propulsion of the sailboard hull and adapted to receive wind for motive power; a skeg positioned and oriented in a rear central portion of the sailboard hull, the skeg being adjustable between a first position, whereby the skeg has a surface area sufficient to prove lateral resistance to side forces generated by the said and to provide directional stability to the sailboard hull when sailing upwind, and a second position, whereby the area of the skeg is reduced for sailing downwind; and a housing for the skeg which facilitates vertical upward and downward movement thereof, the housing having an opening configured and positioned about the skeg to minimize air entrainment between the housing opening and skeg to the underside of the sailboard hull due to forward movement thereof.

Abstract: A protective cover for a surfboard or the like has a cushioned end with protective pockets to enclose the fin(s), and also can cover an end of the surfboard. The fin-receiving pockets are formed between air-filled plenums or bodies of shock-absorbing material such as foam. A closure strap can encircle the surfboard for holding the protective cover in place, or a zipper closure can be provided. Preferably a carrying strap is included, and/or a strap to hold the cover to a car-top carrier.

Abstract: A frangible sailboard fin retainer and method of releasably retaining a fin to a sailboard fin box including forming complementary openings in the fin and the fin box, inserting a bolt assembly having a bolt and a threaded female threaded member joining the fin and fin box. A portion preferably a position of the threaded member is brittle and breakable upon impact of the fin as a result of an aftward blow on the fin.

Abstract: An actuating mechanism is provided for controlling external devices by means of coaxial actuating cables or other suitable linkages. The actuator includes an internal slide element movable to selected detent positions by means of a lever arm which pushes against the slide when raised. The slide is returned to its starting position by depressing the lever arm. Indicator openings are provided in the body of the actuator permitting visual inspection of the position of the slide to indicate the control setting selected. Use of the actuator to control and position retractable fins or skegs on a water board is also disclosed. The actuator is positioned on the upper surface of the water board just forward of and between the rider's knees and coaxial actuating cables link the actuator to retractable fins on the underside of the board. The actuator can be easily manipulated with one hand to retract or extend the fins quickly. The indicator feature indicates the fin setting selected.

Abstract: The water craft is provided with a longitudinally disposed recess in the deck with a pair of ridges defining the recess and extending along the sides of the craft. Each ridge is rounded with respect to a centrally disposed rounded crown in the recess so as to provide a surface against which a windsurfer may stand during windsurfing. The ridges are also more gently rounded with respect to the crown in a stern section of the craft to provide for a comfortable seating arrangement for sailing or rowing purposes. The underside of the craft is provided with a pair of runners along the longitudinal edges and a centrally disposed chines. In addition, a winglet extends from the terminal rear end of each runner in order to enhance stability of the craft in water and to direct water out the sides of the stern during sailing.

Abstract: The top surface of the rear end of a slalom water ski is modified by adding a special contour to same to improve its performance in racing competition. The modification relates to adding a "hump" or "hummock" on the rear one-third of the ski. The sides of the hump coincide with the sides of the rear of the ski and the curvature at the back of the "hump" just matches the contour of the back end of the ski. Also in this hump, the standard seven degree angle from vertical of a standard ski continues upwardly for a given distance above the normal top surface of the ski and is then reversed from that 7 degrees to 7 degrees from vertical the other way for a given distance, after which the top surface of the "hump" is smoothly "radiused" around.