Abstract: A fin for use on a surfboard, the fin comprising: a leading edge, a trailing edge, and a base, the base comprising at least one mount for mounting the fin onto a surfboard; a first and a second outer fin surface which meet along the leading edge and the trailing edge and abut the base; and a first ridge protruding laterally from the first outer fin surface, and/or a second ridge protruding laterally from the second outer fin surface; wherein the shape and configuration of the fin creates an area of lower water pressure around and in front of the fin, as well as disrupting and/or reducing the size of trailing vortices, resulting in additional forward thrust for the board on which the fin is mounted.

Abstract: A water ski fin comprising a planar body and a plurality of chevrons. The planar body may have a top end, a convex leading edge, and a trailing edge. The mounting elements on the top end may mount the fin on a tail of a water ski. A bottom may connect the leading edge to the trailing edge. A plurality of chevrons may have alternating crests and troughs positioned in the trailing edge.

Abstract: A recreational watercraft system of interconnectable, inflatable tubes that can incorporate a configurable frame that may be removably affixed at different vertical heights to attachment brackets that are axially strapped around the inflatable tubes. A plethora of accessories are available to accommodate, oars, paddles, masts, motors and the like, depending on what watercraft shape has been assembled. It can be assembled into a canoe, raft, motorboat, sailboat, fishing float etc.

Abstract: A watercraft includes a pair of inflatable pontoons. Releasably affixed atop each of the pontoons and aligned therewith are inner and outer lengthwise frame members. Forward and aft beamwise frame members are affixed to the inner and outer lengthwise frame members. Primary arch members are affixed to the forward and aft beamwise frame members. A main fabric panel is stretched between the pair of primary arch frame members, the forward beamwise frame member, and the aft beamwise frame member. A motor mount is affixed centrally to the aft beamwise frame member, the motor mount being configured to removably support a motor assembly. Aft panel side members are rotatably-lockably affixed to the aft beamwise frame member and joined by an aft panel top member. An aft fabric panel is stretched between the aft panel side members, the aft beamwise frame member, and the aft panel top member.

Abstract: The present invention is used in water board sports but maybe of benefit to other water vessels; the present invention assists in the planing of water sport boards; the present invention was initially designed for windsurfing it can be used in surfing, kite-boarding and with other water crafts; the present invention uses one or more hybrid-fins, referred to as Squid-Fins™, along with a new base and fin-box that allows for more adjustments and easier swapping of fins; this system helps the board get up on a plane earlier and stay on that plane longer along with making it possible to add new characteristics to the performance of the board.

Abstract: A fin system for releasibly securing a fin to a water craft the system including: a fin box with at least one elongated slot open at a first surface of the fin box and extending a depth inward towards a closed base opposite the first surface; one or more fixed securing features in the fin box, below the first surface and adjacent and open to the at least one elongated slot; one or more vertical access slots in the fin box, open at one end to the first surface, adjacent and open to the at least one elongated slot and extending the depth inwards towards the closed base; and, a fin with a fin base dimensioned to be slideably received by the at least one elongated slot of the fin box, wherein the fin base includes one or more fixed fin attachment mechanisms each having at least one tab or recess dimensioned to be received first by the one or more vertical access slots and received subsequently by the fixed securing features, wherein an engagement of the at least one fin tab or fin recess with the securing feature

Abstract: A stabilizing fin or keel utilizing biomimic design features for use on surface planing or submerged watercraft to provide increased dimensional stability, control and efficiency.

Abstract: A fin plug (10) for a water craft, said fin plug (10) including: a top surface (15) and a bottom surface (20); at least one fin cavity (25), for receiving a base element of a fin, extending inwardly from at least one opening in the top surface (15); and at least one hole (35) or recess in the top surface (15) adapted to be filled with foam.

Abstract: A sportsboard locking device that fits into the horizontal channel of the standard finbox, the device having a housing with an internal slot, an extending flange and a lower club foot, the device further having a slider with a lever on top, the slider capable of sliding down through the inner slot of the housing and into the horizontal channel such that the lower club foot on the extending flange is locked into place within the track underneath the horizontal channel.

Abstract: A sliding fin for a surfboard includes a base having a planar tab with an upper flange, a large fin piece having a first indentation, and a small fin piece for mating face-to-face with the large fin piece. The second fin piece has a second indentation that forms a channel that has a cross-sectional shape corresponding to a cross-sectional shape of the planar tab and upper flange, the channel being longer than the width of the planar tab, the small fin piece being translucent to enable the planar tab in the channel to be seen, the large and small fin pieces being slidable relative to the base on the planar tab.

Abstract: The present invention is a stand up paddle board with left and right oars attached to left and right transmissions respectively mounted in the hull of the paddle board. The hull of the paddle board also includes a bow, stern and foot pads upon which the operator stands on. The oars pivot around an oar pivot in a longitudinal direction and paddle arms attached to the oars pivot around an arm pivot in a longitudinal direction. The paddle arms terminate in at a lower at a paddle so that when the operator urges the oars in a rearward and forward motion, the paddle arms pivot around an arm pivot and propel the paddle board.

Abstract: A concealably retractable handle is ensconced into the core or hull of a recreational or utilitarian floatation structure such as a canoe, kayak, surfboard, sailboard, paddle board or the like, where it lies below the outer surface without interfering with normal use of the structure. The handle can be conveniently extracted and secured in an operational position to facilitate handling and carrying the structure or securing it the a vehicle. The housing of the handle is bonded into the body of the floatation device through a padding sleeve which absorbs stress forces that could damage the solidity of the bond and the integrity of the whole structure. During handle retraction structures encourage agitation of water located inside the housing to facilitate water and debris evacuation.

Abstract: A marine vessel includes an outboard motor mounting portion provided at a stern of a hull, an outboard motor locating hole provided rearward of the outboard motor mounting portion and near the outboard motor mounting portion and penetrating vertically through the stern, a platform provided rearward of the outboard motor locating hole, and an outboard motor located in the outboard motor locating hole and mounted to the outboard motor mounting portion. This structure enables an occupant of the marine vessel to freely move in a space around the outboard motor on the platform and use the space.

Abstract: A breakaway device for locking connected objects in relation to one another comprises a first magnetic field structure attached to a first object and a second magnetic field structure attached to a second object. The first magnetic field structure becoming attached to the second magnetic field structure when substantially aligned. The first structure and the second structure becoming detached when subjected to a force that overcomes a spatial force between the first magnetic field structure and the second magnetic field structure. The first magnetic field structure and the second magnetic field structure having magnetic field sources with polarities and positions in accordance with a code corresponding to a desired spatial force function.

Abstract: A fin box for releasable attachment of a fin having at least one fin-tab, the fin box adapted for insertion into and retention within a water board, the fin box including: a generally elongate body provided with a substantially rectangular recess open at a first surface of the body, the recess extending to a base proximal to a second surface opposite the first surface, and the recess having a forward end and a rearward end; wherein the structure is provided with at least one angled threaded hole extending from the first surface of the body to emerge at a point within the recess between the first surface and the base of the recess.

Abstract: A marine propulsion device is provided with a breakaway skeg having first and second attachment points. The first and second attachment points are configured to result in the second attachment points disengaging from a gear case or housing structure prior to the first attachment point. The attachment points can comprise open or closed slots and, when an open slot is used for the first attachment point, it can be provided with a first edge along which a first pin can exert a force along a preselected angle in response to an impact force on the skeg. The arrangement of attachment points allows a reaction force at the second pin to be predetermined in a way that assures the detachment of the skeg from the housing structure prior to the detachment of the housing structure from another structure, such as the boat hull, or transom.

Abstract: This invention discloses a fin, for use on a surfboard and other watercraft, of a low-drag, high-lift, high-aspect-ratio, low-sweepback-angle planform of symmetrical foil section, with a fit root section that has a forwardly projecting leading edge and cutaway at the trailing edge, alone or in combination with winglets placed on the vertical fin element so as to minimize tip-vortex drag, so as to make the surfboard or watercraft more maneuverable, easier to propel through the water, and to stabilize the surfboard or watercraft.

Abstract: A fin box for releasable attachment of a fin to the body of a surfboard or the like; said fin including a fin-tab associated therewith; said fin box adapted for insertion into and retention within said surfboard; said fin box further adapted for reception and releasable retention of a plurality of fin-tab configurations thereby to releasably retain said fin in fixed relationship to said surfboard; and wherein a first surface of said fin box is of a length and a width sufficient to support said fin entirely so that no portion of said fin is in contact with the body of said surfboard or the like.

Abstract: Provided is a system including a fin box that allows surboard fins to be installed, removed or adjusted to the front or rear of the board within the box and a means for installing the box on the surfboard. More importantly, the fins can be installed in the fin box, and adjusted or removed from the fin box without the use of tools. By using the fin box installation system, manufacturers can effectively locate, align and install the fin box on the surfboard. More importantly, the manufacturers are able to lean and rotate the fins precisely at any desired angles and achieve precise and critical symmetrical mounting of the fins with relation to the centerline of the surfboard.

Abstract: Fin assemblies for a variety of watersport boards including wakeboards, sailboards, surfboards and the like. The fin assemblies include a fin cap, at least one fin base and at least one locking member. Fin assemblies are secured to a watersport board by passing at least one locking member through channels in the board and fin base and into sockets in the fin cap. Fin assemblies are reconfigured by first removing the locking members, arranging the desired combination of fin cap and fin base suitable for current water conditions and/or user ability and then resecuring the fin assembly to the board with locking members.

Abstract: A pivotal fin system, for use with an aquafoil, such as surfboards, body boards, wave skis, sail boards, wake boards and the like, comprising a pot (3) and a fin (2), having a tab (18) extending from the base (17) of the fin (2). The pot (3) has a central slot (11) and is mounted in the board (23) with the opening of the central slot (11) flush with the board (23). The slot (11) has a releasable locking means (6 & 7) therein, and the tab (18) has a connection means (21 & 22), which is releasably engaged by locking means (6 & 7). Preferably the releasable locking means (6 & 7) is a substantially c-shaped clamp, and the connection means (21 & 22) has a recess or recesses (22) behind a bulbous extension (21), which is engaged in the c-shaped clamp, with arms (5) of the c-shaped clamp engaging in the recess or recesses (22).

Abstract: A t-shaped, hydrodynamic fin (“t-fin”) for surfboards designed to maximize performance and maneuverability of the surfboard by creating, in conjunction with two vertical side fins, two chambers to funnel and control the flow of water. The crosspiece of the t-fin is parallel to the surfboard and is horizontal when the surfboard is level from side to side. But also functions as a vertical fin when the board is tilted sideways (in either direction) and the side fins lose their verticality. The t-fin enhances surfboard maneuverability by maintaining fin perpendicularity on the board at all times. The t-fin is fastened to the underside of the surfboard, at the stern, but a second t-fin may be fastened at the same time to the bow underside, to achieve a surfboard that can be used reversibly. T-fins are custom-made, shaped and contoured, and the crosspiece of the t-fin affixed, to achieve the desired hydrodynamic effect.

Abstract: In mounting of a fin on a surfboard, there is formed a through hole within the surfboard with the fin to be mounted within the through hole and extend from the underside of the surfboard. The through hole is normally open the top side of the surfboard. A cover, comprising a thin flexible base, is adhesively secured onto the top side of the surfboard surrounding the through hole. The cover includes a nametag which is removably mounted in conjunction with the base. Removing of the nametag permits access into the surfboard fin mounting box.

Abstract: An articulated fin of the present invention includes a nose section, a tail ection, an upper flexible control surface, and a lower flexible control surface. The upper and lower flexible control surfaces each span from the tail section to the nose section. The fin further includes a gear assembly for applying compressive and tensile forces on the upper and lower flexible control surfaces. The gear assembly bends the tail section upwardly upon applying a tensile force on the upper flexible control surface and a compression force on the lower flexible control surface, and bends the tail section downwardly upon applying a compression force on the upper flexible control surface and a tensile force on the lower flexible control surface.

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 movable centerboard for water craft capable of multiple settings having an upper position within the hull, a lower position at full depth below the hull and multiple settings therebetween such that the system is adapted to receive and operate the centerboard from above. The centerboard and centerboard well are adapted to operate in concert whereby, multiple board positions may be utilized. Introduced from above, the centerboard slides down to an upper position within the hull, from here it can either pivot up completely into the well or it can continue to slide diagonally to its maximum depth whereupon it can pivot to the vertical lower position. The selected positions of the centerboard are held in place by a control pressure wedging device from above, whereupon being struck from below will release allowing the board to pivot and transverse up into the well.

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 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 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 windsurfer board is formed, towards the tail end thereof, with a slot in which a box is fitted. The box provides a mounting for a fin which is movable, while in use, relative to the board in such manner as to permit simultaneous adjustment of the inclination of the fin relative to the board and of the extent by which the fin projects downwardly beneath the board. The mounting for the fin includes a bracket pivotally connected to the box and to the fin.

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: A flexible airfoil section for a wing or a blade comprising a streamlined shape and an elastic structure whose stiffness distribution along its chord and span is tailored to provide a desirable cambered shape with proportional increases in camber with increases in lift, mounted to a supporting structure such that the airfoil sections are free to pivot about axes near their leading and trailing edges. In operation, the foil derives much of its lift from elastic bending deformation of its flexible shape, thereby achieving a higher lift than a symmetric foil at the same angle of attack while postponing the onset of flow separation and stall and, for operation in water, of ventilation and cavitation.

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 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: A lightning protection installation for boats comprising a copper lightning rod mounted on the top of the mast or, in the case of a power boat, mounted on the deck, a copper wire attached to the rod and running downwardly to a point where it is attached to a retractable copper conductor. The copper conductor is retractable through a plastic or fiberglass tube or box molded or inserted in the hull or attached to a centerboard, if available. When the conductor is raised to the passive position, it is protected from the formation of marine growth; and when it is lowered, the conductor provides sufficient wettable electrical conducting grounding surface to conduct the lightning to water ground. Raising the conductor removes the slight drag caused by the grounded conductor.

Abstract: The invention relates to fins for watercraft such as surfboards, surf-skis, sailboards, kayaks, canoes, skiffs, water-skis, and also "soft" plastic watercraft such as polyethylene boards. These fins have an apertured, basal flange; each fin being affixable, in a variety of positions, to the underside of the watercraft via fixing means extending through the apertures in the flange and into the fabric of the watercraft.

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: 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 surfboard is provided with fins, at least one of which is canted at an angle to the longitudinal axis and also tilted relative to the surface of the board, and reinforcing fibers are applied to extend continuously from along the fin to along the board, and adhered to each.

Abstract: This invention is a transom-mounted combination casting seat and anti-drift fin, herein called a transom fin seat. The transom fin seat includes a fin stem, a fin deployed at the bottom of the fin stem, a rigid or pivoting casting seat affixed to the top of the fin stem and a mounting mechanism affixed to the fin stem for securing the transom fin seat to the transom of a boat. In a preferred embodiment, the mounting mechanism is characterized by a transom bracket attached to the fin stem and adapted for engaging the boat transom. In a most preferred embodiment, the transom bracket includes one or more screw-type clamps for removably clamping the transom bracket to the boat transom.

Abstract: A generally trapezoidal fin (22) is pivotally fastened to a casing which can receive the entire fin, permitting total retraction of the fin. The casing is formed with at least one notch (42) for selectively positioning the fin relative to the casing. In a preferred embodiment, the fin is operated by a lever member (26) which has a knob (50) at its distal end for use in positioning the fin (22) from above.

Abstract: A boat, especially a catamaran, having a rectangular collapsible frame with a one-man mast stepping structure. The tubular frame is comprised of fore, aft and central sub-frame assemblies which can be collapsed so as to be easily car topable and serve as a rack for containing other components of the catamaran. Inflatable hulls are secured in bracket arches on the undersides of the sub-frame assemblies. A rudder frame or cage is pivotally mounted on an aft sub-frame assembly and is adapted to receive a rudder, which is identical to and interchangeable with daggerboards. A system of adjustable rope stays is provided for adjusting the mast.

Abstract: A sealing lip assembly for surfboards or sailboats, which closes the underwater side of the opening of the centerboard case or fin case in a virtually flow-tight and non-vortical manner in every position of the centerboard, and including two sealing lips, with each lip defined by a sealing area capable of flexing along the longitudinal axis of the assembly, a resilient area perpendicular to the longitudinal axis, and a mounting portion.

Abstract: The lip gasket for the daggerboard well of a sailboard (1) exhibits two supporting strips (3) embedded in the board body on both sides of the daggerboard well opening (2), as well as two cover strips (5), terminating with the profile (4) of the underwater hull and designed as clamping strips, for being clamped into the supporting strips (3). The cover strips (5) consist of a flat extruded profile exhibiting an outer clamping zone (6) of a hard synthetic resin, for example polyvinyl chloride, and an inner zone, forming a sealing lip (7), of an elastic synthetic resin, for example polyurethane. The two sealing lips (7) of the lip gasket constitute an elastic, tight seal of the daggerboard well opening (2) in the folded (8') and in the deployed (8") position of the daggerboard (8).

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: A fin which can be secured in the channel of a curved fin box in a plurality of locations. The fin has a grooved flange which mates with the open channel of the fin box. One wall of the channel has a groove which aligns with the flange groove and a fastening rod is inserted therein. The fin is prevented from longitudinal movement within the channel by a tab and tab receiving. A pair of the curved fin boxes and fin are affixed to a surfboard as thruster fins. The manuverability of the surfboard is enhanced and can be varied by the repositioning of the thruster fins within the curved fin boxes. At one extreme the line of the fins is parallel to the center line of the surfboard, and at the other extreme the thruster fins are toed-in and form equally but oppositely directed angles with respect to the center line.

Abstract: A fin system for surfboards, wind surfers or similar sporting equipment having an elongated channel extending lengthwise underneath the board. The fin is adjustable in the channel by the interaction of a resilient finger cut out of the fin base with a ribbed inner surface of the channel. The fin is totally removable from the channel, and when inserted, moves along the channel by pressure applied to the base of the fin. Releasing the pressure on the base causes the resilient finger to engage a notch in the ribbed surface and securely positions the fin at the desired point in the channel.

Abstract: The invention relates to a sailboat with a keel board that is inclinable sideways. A single keel board is resiliently inclinable due to the effect of the water which rotates it about an axis disposed substantially in the vertical plane of longitudinal symmetry of the boat and inclined with respect to the horizontal, rising towards the bows of the boat, so as to provide hydrodynamic lift of the inclined keel board compatible with a movement of the boat along its longitudinal axis. In the case of a boat with two inclinable keel boards, the axes of inclination can converge towards the bows of the boat.

Abstract: A reversible airfoil generally wing-like in shape comprising at least two spaced apart rigid spars having at least two slots therethrough, bars projecting through the slots in each rigid spar, each end of each bar attaching to a flexible slat, and a common flexible movable skin adjacent the flexible slats thereby covering same to form a reversible airfoil. A series of the rigid spars and attending parts when covered by a common flexible skin and adapted to fit on a beam provides a unique sail for a sailboat. Additionally, a series of the rigid spars and attending components when covered by a common flexible skin and vertically mounted on a rotatable frame provides a reversible lift airfoil for a wind-powered generator.