SELF STABILIZING MONOWING HYDROFOIL

TECHNICAL FIELD OF THE INVENTION

This invention relates generally to hydrofoils. More specifically, this invention relates to a monowing hydrofoil that provides inherent pitch stability during use.

BACKGROUND OF THE INVENTION

Numerous aquatic recreational activities are commonly enjoyed by the general public, including paddle boarding, windsurfing, kiteboarding, surfing, wing boarding and other similar activities. Of course, each of these activities utilizes a floating board which is propelled across the surface of the water by natural (i.e., wind, surf, etc.) or power generating means (i.e., paddle, propeller, etc.). To increase the speed and maneuverability of these boards, hydrofoils are commonly utilized, which extend into the water below the board and generate lift to reduce or eliminate the frictional drag of the board's contact surface with the water.

A mast or other similar elongated, rigid structure is commonly utilized between the board and hydrofoil to create a predetermined vertical distance of the hydrofoil from the board. Prior art hydrofoils generally comprise bi-wing structures, namely, front and rear wings connected to one another by a fuselage, with the fuselage generally connected to the aforementioned mast. As is commonly understood in the art, the front wing of the hydrofoil primarily generates the lift while the rear wing provides stabilization; similar to the forward and rearward wings of an airplane.

Bi-wing hydrofoils, however, suffer numerous disadvantages. A primary disadvantage is reduced maneuverability. Because the rear wing is horizontally displaced from the front wing by the fuselage, adjusting the angle of the hydrofoil via the mast, through an adjustment of the angle of the board, is difficult due to the resistance of the rear wing and fuselage against any pitch, yaw, and roll movements made within the water. Also, the presence of the rear wing creates additional material, fabrication and shipping costs due to the additional weight and materials of the rear wing itself and the additional fuselage length necessary to accommodate it. Furthermore, rear wings have been known to cause injury when a user of the board falls therefrom and contacts the small blade-like shape of the wing; often resulting in skin lacerations.

To remedy the foregoing disadvantages of bi-wing hydrofoils, monowing hydrofoils have been developed within the prior art. See, for example, U.S. Pat. No. 9,586,659 entitled “Power Hydrofoil Board.” Unlike bi-wing hydrofoils, monowing hydrofoils utilize a single wing, with or without a fuselage, to both generate lift and provide stability. Unfortunately, like bi-wing hydrofoils, prior art monowing hydrofoils suffer from numerous disadvantages. A primary disadvantage present in prior art monowing hydrofoils is a failure to remedy the wing's inherent lack of pitch stability resulting from the lack of the rear stabilizing wing. Thus, prior art monowings have a tendency to pitch up or down uncontrollably, thus rendering the board uncontrollable for the user.

One remedy present in the prior art is to simply make the wing “bigger” (i.e., provide a wing of greater surface area) and rely on the advanced board handling skills of “expert” riders to counteract any unstable movements of the board created by the monowing. Unfortunately, however, this remedy is inadequate because it limits access to monowing hydrofoil boarding only to such expert users; thus eliminating an entire and financially lucrative market of potential novice or intermediate users. Furthermore, expert board users, although fully capable of handling the instability of a prior art monowing hydrofoil, would rather focus on “enjoying the ride” of the board than concentrating on counteracting its instability.

Another inadequate remedy for stabilizing monowing hydrofoils is to add a propulsion system to the monowing or associated mast. For example, U.S. Pat. Registration No. 9,586,659 utilizes a ducted propeller or jet pump driven by an electric motor. The forward thrust of the propulsion system provides a lateral stabilizing force that counteracts the pitch instability of the monowing. However, this remedy, too, is inadequate because it requires the addition of a costly component (i.e., a motor driven propeller) be added to the hydrofoil or mast. Also, users of wind or wave driven hydrofoil boards do not need the additional propeller driven component and the needless cost and frictional drag that it creates within the water.

A further inadequate remedy is the utilization of a canard or (i.e., a small wing located forward of the monowing) or small tail wing located rearward thereof. However, the addition of these wings defeats the entire purpose and related advantages of utilizing a single wing, and thus requires the presence of a fuselage or mounting means for connecting them thereto. In lacking a fuselage, the prior art monowing hydrofoils also lack the rigidity necessary to facilitate its connection to the mast of the board, with such connection possibly having removable properties.

Additionally, presently available hydrofoils do not have a selectively adjustable angle of attack such that the angle between the foil and mast can be increased or decreased to adjust the foil's performance to suit a given user's skill set.

Thus, what is needed is a monowing hydrofoil that possesses inherent pitch stability during use without requiring the need for a large wing size and “expert” board user, a propulsion system, and/or the addition of canards or tail wings. Instead, stability of the monowing should be present within the wing design itself, thus making it inherently stable. The monowing should also be sufficiently rigid to facilitate its connection to the mast of a board, with such connection preferably being removable. The foil should also optionally have an adjustable angle of attack such that the angle can be increased or decreased to suit a given user's skill set. The present invention satisfies the foregoing needs and provides other advantages over the prior art as well.

SUMMARY OF THE INVENTION

This invention relates generally to hydrofoils. More specifically, this invention relates to a monowing hydrofoil that provides inherent pitch stability during use. The monowing comprises a body defining leading and trailing edges and a central portion connecting two opposing rearward swept wing portions, with the central portion of the body preferably defining a lateral front straight line at the leading edge. The monowing has a profile that defines a trailing edge reflex in its camber line (i.e., the line defining the asymmetry between the body's upper and lower surfaces) to produce a pitch-up moment at zero lift. The monowing profile defines a predetermined maximum negative mean camber line (i.e., reflex) aft of a given percentage of its chord, defined as the distance between the leading and trailing edge of the body. A positive camber with an appropriate upper to lower body thickness reaching a predetermined maximum camber and thickness occurs at a different percentage of its chord length to ensure that the monowing hydrofoil produces sufficient lift at lower speeds.

The monowing's negative camber or reflex is further enhanced by the definition of the body's trailing edge and by an upwardly swept central extension rearwardly extending from the central portion and laterally into each rear-swept wing portion. The central extension preferably defines planar upper and lower surfaces that preferably terminate in a rear lateral straight line at the trailing edge of the body between the rear swept wing portions. The rear lateral straight line of the central extension is about parallel to the front lateral straight line of the central portion at the leading edge. The leading edge of the body is “swept-back” by a predetermined angle along each of the two rearwardly swept wing portions from the front lateral straight line defining the central portion at the leading edge. The combined effect of the rearward sweep of the wing portions with the central extension's upward sweep adds to the positive zero-lift pitching moment of the monowing.

The monowing defines a wing twist whereby outer tips of the respective rearwardly swept wing portions each define a more severe downward angle than the body's central portion, which is located forwardly thereof. Thus, the outer tips produce more lift at stall speed than the central portion, which also improves the monowing's zero lift pitching moment. Each wing portion tip of the rearwardly swept wing portions preferably defines a “Hoerner” shape or cross-section, which further adds to the zero-lift pitching moment and further increases the monowing's pitch stability.

The monowing preferably defines a mast interface along its central portion. In one embodiment, the mast interface comprises an upwardly directed stantion of streamlined or narrow ovoid cross section and configured for removable operable abutment to the lower end of a mast. The stantion preferably defines one or more orifices axially aligned with one or more voids defined within the lower end of the mast to accommodate fasteners, such as screws or bolts, and or strengthening components, such as keys or mortises.

In another embodiment, the mast interface comprises a cavity defined in the central portion the body configured to accept the insertion of the mast's lower end therein. An interface housing or at least one collar may be located at the lower end of the mast for operable engagement with the cavity. The at least one collar may optionally comprise one of a plurality of selectively interchangeable collars configured to change the angle of attack (i.e., angle between the foil and mast) of the hydrofoil. The body at the cavity preferably defines one or more orifices axially aligned with one or more voids defined within the lower end of the mast or interface housing to accommodate fasteners, such as screws or bolts, and or strengthening components, such as keys or mortises.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view of one embodiment of the monowing hydrofoil;

FIG. 2 is a camber line graph of the monowing hydrofoil of FIG. 1 as analyzed across section A-A;

FIG. 3 is an upper plan view of the monowing hydrofoil of FIG. 1;

FIG. 4 is another perspective view of the monowing hydrofoil of FIG. 1 illustrating a detail of the wing portion tips;

FIG. 5 is a sectional view of the monowing hydrofoil of FIG. 1, as defined across section B-B to illustrate details of an embodiment of the mast interface;

FIG. 6 is a perspective view illustrating another embodiment of the mast interface;

FIG. 7A is an upper assembly view of another embodiment of the mast interface;

FIG. 7B is a lower assembly view of the embodiment of FIG. 7A;

FIG. 8 is a perspective view illustrating a further embodiment of the mast interface;

FIG. 9A is an upper assembly view of yet another embodiment of the mast interface;

FIG. 9B is a lower assembly view of the embodiment of FIG. 9A; and

FIG. 9C is a sectional view of the collar of FIGS. 9A and 9B.

DESCRIPTION OF THE EMBODIMENTS

This invention relates generally to hydrofoils. More specifically, this invention relates to a monowing hydrofoil that provides inherent pitch stability during use. The pitching moment (i.e., upward and downward angled movement) of a hydrofoil, when used in recreational aquatic boarding activities, is generally controlled using front and rear foot pressures applied to the board by the user. These pressures create a moment through the mast that is transmitted to the hydrofoil to change its pitching moment. The pitching moment of the hydrofoil is described mathematically as follows: text missing or illegible when filed

Within the foregoing formula, text missing or illegible when filed

is the zero-lift pitching moment coefficient, □ is the angle of attack measured with respect to the angle of attack at which the hydrofoil produces zero lift, and is the pitching moment coefficient gradient with angle of attack. Within the equation, the magnitude of the gradient is influenced by the front and rear foot pressures of the board's user. To achieve pitch stability, a negative pitching coefficient moment gradient (□<0) and a positive zero-lift pitching moment coefficient text missing or illegible when filed

>0) is required, with the positive (pitch up) zero-lift pitching moment coefficient enabling “front foot pressure” on the board for control by the user. In prior art bi-wing hydrofoils, this positive zero-lift pitching moment coefficient and associated front foot pressure is produced by a negative incidence angle of the rear wing, with prior art monowing hydrofoils largely failing to produce it altogether.

As illustrated in FIG. 1, the present monowing hydrofoil 5, remedies the foregoing deficiency of those in the prior art and thus produces the necessary positive zero-lift pitching moment coefficient through a novel combination of wing shape, twist, profile and trailing edge shape. The monowing 5 comprises a body 10 defining leading and trailing edges 15 and 20 and a central portion 25 connecting two opposing rearward swept wing portions 30 and 35, with the central portion of the body preferably defining a lateral front straight line 40 at the leading edge. The body 10 is preferably comprised of molded carbon fiber materials. However, it is understood that it may be comprised of fiberglass, plastic, wood or other light-weight, rigid materials as well.

Referring to FIG. 2, which illustrates a cross section of the central portion 25 of FIG. 1 taken along plane A-A, the monowing 5 has a profile that defines a trailing edge reflex in its camber line (i.e., the line defining the asymmetry between the body's upper and lower surfaces 45 and 50) to produce a pitch-up moment at zero lift, that is, contributing to a positive, in Equation 1. As illustrated in FIG. 2, the monowing profile defines a maximum negative mean camber line (i.e., reflex) of between about 1% and 6% aft of about 70% of its chord, defined as the distance between the leading 15 and trailing edge 20 of the body 10, measured parallel to the normal airflow over the body, as measured from the body's leading edge. A positive camber with an appropriate upper to lower body thickness reaching its maximum camber and thickness (30 mm+/−) around 20% of its chord length measured from the body's leading edge 15 ensures that the monowing hydrofoil 5 produces sufficient lift at lower speeds. The foregoing combination of mean camber and body thickness defines a pronounced “drooping nose” of the monowing 5. The “drooping nose” reduces the amount of flow acceleration around the leading edge 15 as stall is approached and thus results in a softer stall. Generally speaking, once a hydrofoil stalls, any further increase in angle results in a loss in lift and increase in drag; which can undesirably occur abruptly. The “drooping nose” softens the stall behavior such that lift does not collapse once stall is reached, thus improving low-speed performance of the monowing 5.

Referring again to FIG. 1 and also to FIG. 3, the monowing's negative camber or reflex is further enhanced by the definition of the body's trailing edge 20 and by an upwardly-swept central extension 55 rearwardly extending from the central portion 25 and laterally into each rear-swept wing portion 30 and 35. The central extension 55 preferably defines planar upper and lower surfaces 60 and 65 that terminate in a rear lateral straight line 70 at the trailing edge 20 of the body 10 between the rear swept wing portions 30 and 35. In other embodiments, however, the upper and lower surfaces 60 and 65 define convex and/or concave arcuate shapes. The rear lateral straight line 70 of the central extension 55 is preferably about parallel to the front lateral straight line 40 of the central portion 25 at the leading edge 15.

In a preferred embodiment, the rear lateral straight line 70 of the central extension 55 at the trailing edge 20 is located about 80 mm rearwardly of the body's central portion 25, as defined along a horizontal axis bisecting the body 10 and extension, and is upwardly angled from the horizontal axis by between about 9 and 13 degrees. In other embodiments, however, the central extension 55 at the trailing edge 20 is located between about 20 mm and 170 mm rearwardly of the central portion 25 and defines an arcuate or angular line at the trailing edge 20. The leading edge 15 of the body 25 is “swept-back” by between about 20 and 45 degrees along each of the two rearwardly swept wing portions 30 and 35 from the front lateral straight line 40 defining the central portion 25 at the leading edge. The combined effect of the 20-45 degree rearward sweep of the wing portions 30 and 35 with the central extension's 55 upward sweep of between about 9 and 13 degrees adds to the positive zero-lift pitching moment, text missing or illegible when filed

of the monowing 5.

As further illustrated in FIGS. 1 and 3, the monowing 5 defines a wing twist whereby outer tips 75 and 80 of the respective rearwardly swept wing portions 30 and 35 each define a more severe downward angle than the body's central portion 25; which is located forwardly thereof. Thus, the outer tips 75 and 80 produce more lift at stall speed than the central portion 25, which also improves the monowing's zero lift pitching moment. As further illustrated in FIG. 4, each wing portion tip 75 and 80 of the rearwardly swept wing portions 30 and 35 defines a “Hoerner” shape 85 or cross-section, which further adds to the zero-lift pitching moment. The Hoerner shape or cross-section of the wing portion tips 30 and 35 accelerate the speed of the water passing under each tip to a velocity more equal to that of the water flowing over the top to create vortices forward of the tips which, in effect, extend the monowing's span beyond its geometric length to further increase the monowing's pitch stability.

Referring again to FIG. 1 and also to FIG. 5, which illustrates a sectional view of FIG. 1 across plane B-B, the monowing 5 preferably defines a mast interface 90 along its central portion 25. In this embodiment of the invention, the mast interface 90 preferably comprises an upwardly directed stantion 95 of streamlined or narrow ovoid cross section and terminating in a planar surface 100. The stantion 95 may be unitary with the body 10 or connected thereto with glues, resins, bonding agents, screws or other fasteners and/or bonding means understood in the art. The planar surface 100 of the interface 90 is configured for removable operable abutment to the lower end of a mast (i.e., FIG. 6 et seq.), also terminating at a planar surface. However, it is understood that the stantion 95 may be unitary with the lower end 145 of the mast 150 as well.

The stantion 95 preferably defines a pair of axial orifices 105 and 110 located “front-to-back” along the stantion. The forward orifice 105 preferably comprises a through bore extending through both the stantion 95 and body 10 and adapted to accept the insertion of a bolt or screw (not shown) there-through for threaded engagement with a void defined in the lower end 145 of the mast 150. The rear orifice 110 preferably defines a lengthwise slot extending downwardly from the stantion's planar surface 100 and adapted to accept the insertion of a mast key or mortise (not shown) therein for male engagement with a like void defined in the lower end of the mast. As illustrated in the embodiment of FIG. 5, the rear orifice 110 defining the slot may also extend through both the stantion 95 and body 10 to accept an insertion of a bolt or screw (i.e., FIG. 7 et seq.) there-through, with the placement of the bolt or screw “front-to-rear” adjustable therein to accommodate varying locations of the rear threaded opening present in a variety of masts available in the market place.

FIG. 6 illustrates yet another embodiment of the mast interface 90 further comprising the stantion 95 defining a medial orifice 115 between the forward and rear orifices 105 and 110, with the forward orifice preferably defining a through bore 135 extending through the stantion and body 10 for accepting the insertion of a screw or bolt (i.e., FIG. 7 et seq.) there-through for threaded engagement with the lower end 145 of the mast 150. The medial and rear orifices 115 and 110 of the stantion 95 each preferably define a lengthwise slot extending downwardly from the stantion's planar surface 100 and adapted to accept the insertion of respective medial and rear mast keys or mortises 155 and 160 therein for male engagement with the mast's lower end 145. Referring again to FIG. 6, the mast's lower end 145 further defines forward, rear and medial voids 165, 170 and 175 for respective axial alignment with the forward, rear and medial orifices 105, 110 and 115 of the stantion 95. The aforementioned medial and rear keys or mortises 155 and 160 are located within the medial and rear voids 170 and 175 of the mast 150, with the forward void 165 preferably defining the threaded bore 180 for accepting the threaded engagement of the bolt or screw therein. The lower end 145 of the mast 150 also preferably defines a planar surface 185 configured for abutting engagement with the planar surface 100 of the stantion 95.

In yet another embodiment of the mast interface 90 illustrated in FIGS. 7A and 7B, the forward orifice 105 preferably defines a through bore 135 extending through the stantion 95 and body 10 for accepting the insertion of a screw or bolt 140 there-through for threaded engagement with the forward void 165 (i.e., threaded bore); also defined in the mast's lower end 145. The medial orifice 115 defines a rearwardly extending slot extending downwardly from the stantion's planar surface 100 and adapted to accept the insertion of the medial mast key or mortise 155 therein at the slot's forward end 112 for male engagement with the medial void 175 of the mast's lower end 145. The rearward end 113 of the slot extends through both the stantion 95 and body 10 to accept an insertion of a bolt or screw 140 there-through for threaded engagement with the rear void 170 (i.e., threaded bore) defined in the mast's lower end 145. A slot washer 117, defining an outer periphery larger than that of the slot of the medial orifice 115, is located against an underside 118 of the foil's body 10 and defines a slot washer bore 119 there-through. The screw 140, extending through the rearward end 113 of the slot for threaded engagement with the rear void 170 of the mast 150, also extends through the slot washer bore 119 such that the screw's head is tightened against the slot washer 117. The lower end 145 of the mast 150 also preferably defines a planar surface 185 configured for abutting engagement with the planar surface 100 of the stantion 95.

Referring again to FIGS. 7A and 7B, an oblong washer 190 is optionally located between the planar surfaces 100 and 185 of the stantion 95 and mast 150. The washer 190 defines lower and upper planar surfaces 195 and 200 configured for abutting engagement with the respective stantion and mast planar surfaces 100 and 185. The oblong washer 190 further defines forward and medial through openings 205 and 215 configured for axial alignment with the forward and medial orifices and voids 105, 115 and 165, 170 of the respective stantion 95 and mast 150. The washer 190 protects the stantion 95 from incurring possible damage caused by any presence of sharp edges, defined at the mast's lower end 145 for those masts comprising a hollow extruded aluminum member. The washer 190 may also define an outer peripheral edge 220 located outwardly of an outer peripheral edge 225 of the stantion 95 (FIG. 7A) to accommodate the lower end 145 of any mast 150 defining a peripheral outer edge 230 located outwardly of that defined by the stantion.

In another embodiment of the invention illustrated in FIG. 8, the mast interface 90 comprises a cavity 120 defined in the central portion 25 of the body 10. The cavity 120, in turn, defines an inner planar face 125 and adjoining peripheral surface 130 configured to accept the insertion of the mast's lower end 145 therein. The inner planar face 125 of the cavity 120 is configured for abutting engagement with a planar face 132 defined on an interface housing 133 located at the mast's lower end 145 while the cavity's peripheral surface 130 is configured for engagement with an outer peripheral surface 134 of the mast's housing. The inner planar face 125 of the cavity 120 may define one or more of the orifices 105, 110 and/or 115 as defined in the foregoing embodiments. In the embodiment of FIG. 8, the cavity's peripheral surface 130 defines a rounded rectangular shape for accepting the rounded rectangular peripheral surface 134 of the masts' housing 133 therein. However, it is understood that the peripheral surface 130 of the cavity 120 may comprise other polygonal shapes as well for accepting like shapes defined by the peripheral surface 134 of the mast's housing 133, to include trapezoidal, octagonal, hexagonal and other shapes understood in the art.

In a further embodiment illustrated in FIGS. 9A and 9B, the mast interface 90 again comprises a cavity 120 (FIG. 9A) defined in the central portion 25 of the body 10. The cavity 120, in this embodiment, however, defines a stepped portion 235 terminating in an inner planar face 125, and a peripheral socket 240 configured to accept the insertion of at least one collar 245 and mast's lower end 145 therein. The peripheral socket 240 defines a lower peripheral outer planar face 250 terminating in a socket peripheral wall 251. The inner planar face 125 of the cavity 120 is configured for abutting engagement with the primary planar face 252 of a downwardly stepped portion 255 of the mast's lower end 145, with the downwardly stepped portion also defining a pair of co-planar secondary faces 260 and 265 located upwardly of the primary planar face. The pair of coplanar faces 260 and 265 is also preferably respectively located forwardly and rearwardly of the primary planar face 252, with the primary planar face and forwardly and rearwardly secondary faces respectively terminating in forward and rearward risers 270 and 275 defined at the mast's lower end 145.

Referring again to FIGS. 9A and 9B, the forward and rear orifices 105 and 110 comprise through bores 135 defined through the stepped portion 235 and body 10 for accepting the insertion of respective screws or bolts 140 there-through for respective threaded engagement with the forward and rear voids 165 and 170 (FIG. 9B; i.e., threaded bores) defined in the downwardly stepped portion 255 of the mast's lower end 145. The at least one collar 245 is interchangeably located about the stepped portion 235 of the cavity 120 within the peripheral socket 240. The at least one collar 245 defines an oblong, through opening 280 having an inner collar wall 285 terminating at lower and upper collar surfaces 290 and 295, with each of the lower and upper surfaces terminating in a collar outer collar wall 300. The at least one collar 245 further defines a mast abutment 289 comprising the rear portion 305 of the upper collar surface 295 and an about coplanar with a shelf 310 extending rearwardly from a forward portion 315 of the inner collar wall 285 (FIG. 9A). The mast abutment 289 of at least one the collar 245 is configured for removable abutting engagement with the masts' lower end 145 such that shelf 310 of the collar 245 is configured for abutting engement with the forwardly secondary face 260 of the mast's lower end 145 while the rear portion 305 of the upper collar surface 295 is configured for abutting engagement with the mast's rearwardly secondary face 265. The lower collar surface 290 of the at least one collar 245 is configured for removable abutting engagement with a collar abutment 291 of the cavity 120 (FIG. 9A), namely, the lower peripheral outer planar face 250 of the peripheral socket 240.

Referring now to FIG. 9C, which illustrates the collar 245 of FIGS. 9A and 9b in section, the lower collar surface 290 is preferably oriented in relation to the mast abutment 289 such that the lower collar surface may be parallel with the mast abutment, or angled in relation to the mast abutment. Because the lower collar surface 290 is configured for abutting engagement with the lower peripheral outer planar face 250 of the peripheral socket 240, the utilization of a given angle (theta) of the collar's lower surface 290 in relation to the abutment's shelf 310 and rear upper portion 305 effectively allows for the selective adjustment of the angle of the body 10 of the foil 5 in relation to the mast 150, thus facilitating an adjustment of the foil's “angle of attack” and performance by the user.

The angle (theta) of the collar's lower surface 290 in relation to its shelf 310 and rear upper portion 305 is between about 0 and 90 degrees, preferably between about 5 and 45 degrees, and optimally about 10 degrees. To facilitate the foregoing “angle-of-attack” adjustment, a plurality of collars 245 of the foregoing varying degrees of lower surface angle may be interchangeably utilized with the foil 5 according to the user's preferences and skill level. For example, a plurality of collars 245 may be provided with respective lower surface angles (theta) varying in increments of 5 degrees between 0 and 45 degrees such that a user of the foil 5 can interchangeably utilize one of the nine different collars of the plurality to vary the foil's “angle of attack” and performance characteristics.

Although the mast abutment 289 comprises a shelf 310 and rear upper portion 305 configured for abutting engagement with the downwardly stepped portion 255 of the mast's lower end 145, it is understood that the mast abutment may comprise a single planar surface configured for abutting engagement with a single planar surface defined at the mast's lower end, or any number or arrangement of surfaces configured for like surfaces at the mast's lower end.

As best illustrated in FIG. 9B, a pair of opposing ovoid inner side portions 320 and 325 of the collar inner wall 285 are configured for frictional engagement with a pair of ovoid opposing outer side walls 330 and 335 defined by the downwardly stepped portion 255 of the mast's lower end 145. A longitudinal threaded bore 340 is defined through a rear end 345 of the at least one collar 345 for threaded engagement with a set screw 350. An inner surface 355 of the set screw 350 is operably engageable with the rear riser 275 of the mast 150, when the mast is inserted into the collar 245, such that a rotation of the set screw displaces the at least one collar 245 and the mast's downwardly stepped portion 255 of its lower end 145 in relation to one another.

More specifically, a clockwise rotation of the set screw 350 (having its inner surface 355 engaged with the rear riser 275) causes the at least one collar 245 to displace longitudinally in a rearward direction and/or the mast's lower downwardly stepped portion 255 to displace longitudinally in a forward direction, thereby longitudinally driving the ovoid opposing side portions 320 and 325 of the collar's inner wall 285 frictionally against the respective ovoid opposing side walls 330 and 335 of the mast's downwardly stepped portion, thus increasing the frictional engagement between the components. The ovoid geometry of the collar and mast walls acting against one another frictionally secure the mast 150 and collar 245 together such that any movement or “free play” existing between the components is minimized or eliminated.

In a preferred embodiment of the invention, both the collar 245 and mast 150 are comprised of aluminum. Nonetheless, it is understood that one or both components may be comprised of other materials as well, to include stainless steel, thermoplasts, plastics, and carbon-fiber and similar rigid and robust materials. However, where both the collar 245 and optionally the mast 150 are comprised of aluminum and the body 10 of the foil 5 is comprised of carbon fiber materials, a possibility of corrosion occurring to the aluminum components is possible where the foil is used within a salt-water environment. Such corrosion is usually attributed to a galvanic reaction occurring between the carbon fiber and aluminum material that is enhanced by the presence of the saltwater.

However, to minimize or eliminate this corrosion from occurring, an anode 360 and/or anode screw 365 are optionally located between the body 10 and collar 345. As illustrated in FIGS. 9B and 9C, a threaded anode bore 370 is defined upwardly within the at least one collar 245 from its lower surface 290. The threaded anode screw 365 extends through the anode 360 and into the threaded anode bore 370 of the collar 345 such that any galvanic reaction between the body 10 and collar is eliminated or minimized, thus minimizing or eliminating the associated occurrence of corrosion to the aluminum components.

In other embodiments not shown however, stantion 95 itself is configured for male insertion into a cavity defined at the mast's lower end, with the male and female shapes being similar or identical to those of the above-recited embodiments and again defining planar faces for abutment with one another. Regardless of shape and male/female configuration, the stantion and mast end are secured to one another mechanically, by a bonding agent, resin, glue, screws, bolts, or latching mechanism. Also regardless of shape and configuration, the mast interface, in addition to providing for the connection of the monowing 5 to the mast, provides for the increased rigidity of the body's central portion 10 as well.

While this foregoing description and accompanying figures are illustrative of the present invention, other variations in structure and method are possible without departing from the invention's spirit and scope.

SELF STABILIZING MONOWING HYDROFOIL

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CROSS REFERENCE TO RELATED APPLICATIONS

Provisional Applications (1)