Abstract: The present disclosure provides generally for a hydrofoil system that may allow a surfboard to glide above the water surface. According to the present disclosure, a rider may be able to manipulate a hydrofoil device attached to a surfboard with limited training and athletic ability. The present disclosure provides for a hydrofoil system that may allow riders to use a light leaning motion to adjust the angle of a front wing to create forward thrust to produce a flow for creating lift. In some aspects, the front wing may tilt to reduce downward drag force in a lifting phase while locking into place during a glide to provide a sustained lift of the surfboard out of the water.

Abstract: A hydrofoil and hydrofoil system for a surfboard is disclosed. The surfboard has a planar hull defined by a top surface, a bottom surface, a nose, a tail, and opposing side rails extending from the nose to the tail and that define a transition from the top surface to the bottom surface. The hydrofoil system includes one or more attachment mechanisms mounted with the planar hull at or proximate to at least one of the opposing side rails of the planar hull, each of the one or more attachment mechanisms comprising an attachment site oriented substantially laterally from the planar hull. The hydrofoil system further includes a hydrofoil configured to attach to the attachment site of one of the one or more attachment mechanisms, the hydrofoil further being configured to extend substantially laterally from the planar hull at or proximate to the at least one of the opposing side rails of the planar hull.

Abstract: A surfboard, the rear part 1 of which is rigid and equipped for example with one or more fin boxes and other accessories such as foot strap inserts, leash inserts and or a mast box, the front part 2 of which is inflatable and equipped with a valve which permits the said inflatable part to be inflated for use and deflated after use to facilitate transport and storage.

Abstract: A fin with a unique design for use with surfboards.

Abstract: A sailboard hull has at least one pair of winglets or foils beneath the top of the board. Each winglet or foil has above it a slot and allows dynamic lift from both the top and bottom surface of the winglet and reduction of drag when the board is traveling at a transition speed between displacement mode and planing mode. At high planing speed it does not normally have lift from the top surface of the winglet. There may be multiple pairs of winglets or foils. Back slots may be provided at the rear of the sailboard hull providing a higher ratio of winglet width to maximum hull width. A top slot may cover at least half the winglet area, and a winglet may have a camber/slope step on the planing surface.

Abstract: A personal wind-powered hydrofoil watercraft having a sail supported by a mast coupled to a buoyant body, where the mast is tiltable forward and backward but not side to side, in order to prevent excessive rolling of the buoyant body when it is lifted clear of the water on the hydrofoils. Additionally, the buoyant body may be in the shape of a pontoon, the watercraft may be steerable by a steering mechanism actuated by a human operator's foot or feet, and the front hydrofoil may be associated with a surface tracking means in order to stabilize the altitude of the watercraft.

Abstract: A hydrofoil section comprises first and second faces that create, in operation at speeds above a ventilation speed, a ventilated cavity defined by a first cavity face which departs from the first hydrofoil face and a second cavity face which departs from the second hydrofoil face. Each cavity face represents a free surface and each face separating from the said free surface at a discontinuity on that surface, the separated faces forming a continuation of the faces of arbitrary shape and enclosed by the free surfaces without contacting the said free surfaces. Below the speed at which full ventilation occurs the arbitrarily shaped portion of each face is configured to provide a modified flow configuration resulting in changed lift and or drag and or pitching moment under partial, or unventilated operation.

Abstract: A winglet in a planing hull for sailboards with longitudinal length at least three times its transverse width, or a top slot that covers at least half the winglet area, and a forward slot and or a top slot, which allows dynamic lift from both the top and bottom surface of the winglet when the board is traveling at a transition speed between displacement mode and planing mode, but at high planing speed it does not normally have lift from the top surface of the winglet. This winglet may have a camber/slope step on the planing surface. In addition the transverse section of the nose of the hull can have the shape of an upside down wing.

Abstract: A personal wind-powered hydrofoil watercraft having a sail supported by a mast coupled to a buoyant body, where the mast is tiltable forward and backward but not side to side, in order to prevent excessive rolling of the buoyant body when it is lifted clear of the water on the hydrofoils. Additionally, the buoyant body may be in the shape of a pontoon, the watercraft may be steerable by a steering mechanism actuated by a human operator's foot or feet, and the front hydrofoil may be associated with a surface tracking means in order to stabilize the altitude of the watercraft.

Abstract: An improved windsurfing catamaran type vessel. The illustrated vessel has an improved steering mechanism that includes a relatively stiff but bendable plastic rod that is directly received within one or more guiding passageways or grooves formed in the plastic hull of the vessel. The plastic-to-plastic interface between rod and groove provides relatively low friction interengagement as the rod moves. The groove is open to ambient water, which will further reduce the friction. The rod has stiffness/flexibility characteristics that allow it to turn around relatively large radii while still being able to span relatively short distances without significant bending. A manual operative control member is pivotally mounted on the hull and connected to the rod in a manner which multiplies the force applied by the use; this provides the magnitude of force needed to move the rod with minimum exertion by the user.

Abstract: FIG. 1 is an exploded view of the invention that consists of a reusable installation guide or router template, (13), which also doubles as a resin dam to secure receptacle, (9), into substrate (19)-(20). Insert (3) resides in receptacle, (9), and accommodates fin, (1), in angled slot (4). The insert, (3), and fin (1), are secured via grub screws, (10), tightened by Allen key (11). This design will accommodate a wide variety of proprietary fins available from numerous manufacturers who bundle their fin mounting systems to be used only with their fins. The fin can be removed, moved laterally within the slot, and canted by changing the insert. The fin is not part of the instant invention.

Abstract: Apparatus is provided for attaching a fin to the underside of a small watercraft, such as a surfboard. The apparatus includes a holder which is attachable to the underside of the surfboard, so that a recess defined in the holder extends inwardly from the underside. The apparatus further includes a fin sub-assembly comprising a fin and a body which is receivable within the recess defined in the holder. The fin sub-assembly can be received in the holder in a plurality of angular orientations about an axis generally perpendicular to the underside of the surfboard. The invention extends to a holder, a small watercraft, and a method for attaching a fin to an underside of a small watercraft.

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: An adjusting fin for a watercraft consisting of a fin removably attached to a spindle that is held within a fin box. The spindle is rotatable within the fin box such that the fin can pivot with action of water against the fin as the watercraft moves through the water. Adjustable stops act against cams on the spindle to limit the range of rotation available, thus allowing the adjusting fin to be set up to suit the prevailing conditions and the expertise of the user. An optional biasing means biases the fin towards a neutral position which is perpendicular to an underside of the watercraft.

Abstract: A fin plug assembly to receive and engage a fin includes a cavity, a cam with gears, and a worm gear. The fin plug assembly allows a quick and easy fore-aft adjustment of the fin. Disclosed also is a method of installing the fin plug assembly in a surfboard using a one-piece complete control jig system including the step of providing additional structural strength by removing and/or spiking the foam material in the body of the surfboard.

Abstract: A modified mast and keel system for a sailing vessel. The mast is gimbaled to the hull, so that it can move in a pitch roll. A downward extension of the mast pivotally connects to a winged keel. An aft strut also pivotally connects to the hull and pivotally connects to the winged keel. The hull, the mast extension, the winged keel, and the aft strut combine to form a traditional four bar linkage which is used to adjust the angle of attack of the winged keel with respect to the vessel. The winged keel moves with the mast in pitch and roll. It also includes a hydrofoil having an angle of attack which can be changeable in response to the pitching of the mast. This hydrofoil thereby generates downforce which counteracts the lifting forces created by the mast. It also creates lateral forces to counteract the sideslip of the vessel.

Abstract: A stabilizer for a mobile device includes a first element that has a center-plane and an upper end for attachment to a bottom surface of the mobile device. The stabilizer also has a hollow tubular element that has a center-plane. The hollow tubular element is connected to the first element such that the center-plane of the hollow tubular element and the center-plane of the first element are not aligned.

Abstract: A bottom fin for a watersports board such as a surfboard or a windsurfer board. It has an upper body portion having a leading edge that extends downwardly and rearwardly from its front end. The bottom fin also has a lower body portion having a leading edge that extends downwardly and forwardly from the bottom end of the leading edge of the upper body portion. The upper body portion and lower body portion have a trailing edge that extends downwardly from the rear end of the top edge of the bottom fin all the way down to its bottom end. An elongated bulbous member is connected to the bottom end of the fin. There are attachment lugs extending upwardly from the top end of the bottom fin for securing the fin to the bottom surface of a watersports board.

Abstract: A hydrodynamic device for use with a recreational water vessel such as a surfboard, disrupts a flow of water under the recreational water vessel. A channel member (12) and a fixing device (14) are attachable to an underside of the recreational water vessel. The fixing device (14) may have lugs (44) arranged to be received in corresponding recesses in the underside of the vessel. Water flowing between the underside of the vessel and the channel member (12) passes from a high water-pressure zone to a low water-pressure zone, which enhances forward thrust of the recreational water vessel in the water.

Abstract: A surfboard includes a body, a fin, a chamber disposed in the body, and a fastener. The fin is receivable in the chamber and projects from the body at a cant when received in the chamber. The chamber and the fastener may be components of a fin box disposed on the body of the surfboard. The chamber is configured so that the fin is adjustable in a variety of cants. The chamber may be configured to allow a foot of the fin to pivot within the chamber. When the fin is positioned in a desired cant, the fastener secures the fin in the chamber at the desired cant. To adjust the cant, the fastener is actuated to release the fin, the fin is repositioned at another cant, and the fastener is actuated to secure the fin at the new desired cant. This adjustment of the fin may be repeated any number of times.

Abstract: A foil having a stabilizing hollow element, the entire foil forming a wing- or fin-like shape. The hollow element may also have a leading edge that tapers to a defined point. The hollow element may also have a foil shape, running substantially parallel to the foil profile of the fin- or wing-like extensions.