US20170001695A1

US20170001695A1 - Fin Patent

Info

Publication number: US20170001695A1
Application number: US15/186,837
Authority: US
Inventors: Martin John Lowry
Original assignee: Individual
Current assignee: Individual
Priority date: 2015-06-30
Filing date: 2016-06-20
Publication date: 2017-01-05

Abstract

A fin or finlike structure attached at its base to a hydrofoil or watercraft having one or more channels running along its side surfaces at either a horizontal angle or an acute angle as measured from the intersection of the fin's leading edge and its base. These channels may be arranged side-by-side, separated by the side surfaces of the fin or finlike structure, or separated by flanges or convex shapes in a fashion similar to a true ‘spoiler’ in automobiles. As water moves through these channels it is compressed which consequently creates a drop in pressure and generates a significant increase in speed when compared with a fin or finlike structure having traditionally foiled or flat surface or surfaces. The channels and, when applicable, flanges or convex shapes generate speed, reduce drag, provide additional stability, drive through turns, maneuverability, responsiveness, and, when extending at an acute angle away from the intersection of the leading and base edges, lift. The channels, flanges or convex shapes may be of any acute angle, curvature, number, orientation, shape, size, symmetry and type so long as those characteristics ensure the flow of water through these comparatively narrow ways at increased velocity and with intended direction off the trailing edge and, depending on their orientation, the tail-end, or tip, of the fin. This invention has particular application to the field of wave-riding vehicles such as surfboards, sail boards, body boards, paddle boards, and windsurfing boards but also it will be apparent that the invention has further application to the broader field of watercraft in general.

Description

CROSS REFERENCE TO RELATED APPLICATIONS

1. U.S. Pat. No. 1,571,989 Feb. 9, 1926 P. G. Zimmerman; Aerofoil
2. U.S. Pat. No. 3,201,807 Aug. 24, 1965 G. R. Weaver; Ski Stabilizer
3. U.S. Pat. No. 3,323,154 Jun. 6, 1967 F. A. Lambach; Surfboard
4. U.S. Pat. No. 3,604,661 Sep. 14, 1971 Robert Alfred Mayer, Jr.; Boundary layer control means
5. U.S. Pat. No. 3,680,511 Aug. 1, 1972 John Walter English; Hydrofoils for ships and like vessels
6. U.S. Pat. No. 3,952,971 Apr. 27, 1976 Richard T. Whitcomb; Airfoil shape for flight at subsonic speeds
7. U.S. Pat. No. 4,320,546 Mar. 23, 1982 Carleton R. Knox; Surfboard.
8. U.S. Pat. No. 4,377,124 Mar. 22, 1983 Franck Guigan; Sailboat with an inclinable keel board.
9. U.S. Pat. No. 4,439,166 Mar. 27, 1984 Ralph A. Maxwell; Adjustable water ski fin and wing
11. U.S. Pat. No. 4,644,889 Feb. 24, 1987 Keith A. Krans; Sailboat keel
12. U.S. Pat. No. 4,733,496 Mar. 29, 1988 Peter Wanner; Pivoting surfboard fin
13. U.S. Pat. No. 5,273,472 Dec. 28, 1993 David Skedeleski, Eric Arakawa; Surfboard fins with flexible edges
14. U.S. Pat. No. 5,480,331 Jan. 2, 1996 Tommy R. Lewis; Flexible surfboard fin
15. U.S. Pat. No. 5,813,890 Sep. 29, 1998 Roger A. Benlam; Pivoting fin with elastic bias
16. U.S. Pat. No. 6,322,413 Nov. 27, 2001 Gregory M. Webber; Fin
17. U.S. Pat. No. 6,746,292 Jun. 8, 2004 David G. Panzer; Bottom fin for a watersports board
18. U.S. Pat. No. 7,410,399 Aug. 12, 2008 Bruce Blumenfeld; Body board for recreational use
19. U.S. Pat. No. 7,568,443 Aug. 4, 2009 Jeff Walker; Boat rudder with integrated dynamic trim foils
19. U.S. Pat. No. 7,685,959 Mar. 30, 2010 Roy F. Sanders; Surfboard with graduated channels
20. U.S. Pat. No. 7,896,718 Mar. 1, 2011 Cameron Grant Jones; Fin or keel with flexible portion for surfboards, sailboards or the like
21. U.S. Pat. No. 8,083,560 Dec. 27, 2011 Robert W. Foulke; Pivotal surfboard fin assembly
22. U.S. Pat. No. 8,408,958 Apr. 2, 2013 Roger A. Benham; Pivoting fin with securement
23. U.S. Pat. No. 8,414,344 Apr. 9, 2013 Robert W. Foulke; Pivotal surfboard fin assembly

STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT

Not applicable.

THE NAMES OF THE PARTIES TO A JOINT RESEARCH AGREEMENT

Not applicable.

INCORPORATION-BY-REFERENCE OF MATERIAL SUBMITTED ON A COMPACT DISC OR AS A TEXT FILE VIA THE OFFICE ELECTRONIC FILING SYSTEM (EFS-WEB.)

Not applicable.

STATEMENT REGARDING PRIOR DISCLOSURES BY THE INVENTOR OR A JOINT INVENTOR

Not applicable.

BACKGROUND OF THE INVENTION

Field of the Invention
The invention relates to a fin or finlike structure.
The invention has particular but not exclusive application to fins or finlike structures for surfboards and other hydrofoils and the example of surfboards will be used for purposes of illustration throughout. It is to be understood, however, that this invention relates to fins or finlike structures on a wide array of hydrofoils and watercraft including but not limited to: surfboards, windsurfing boards, sailboards, paddle boards, body boards, wakeboards, waterskis, boats, sailboats, catamarans, water scooters, jet skis, wave runners, yachts, submarines, and any and all other wholly or partially submerged vessels or vehicles.
Description of Related Art
Surfing offers the opportunity for the surfer to perform a variety of maneuvers and tricks that allow him or her to showcase his or her skill and knowledge of the wave. The surfer can return to the source of the wave's power and energy in a number of ways: by performing a ‘cutback’ to the breaking portion of the wave; a ‘bottom turn’ to harness the speed of catching or ‘dropping into’ the wave as it breaks; a ‘stall’ to let the wave catch up and curl over the surfer as it breaks—this last maneuver is often used to position a surfer in the ‘tube’ or inside the curling portion of a wave, all of the rest are designed to position a surfer in the ‘pocket’ or the source of the wave's energy immediately in front of the breaking section which drives the surfer forward with optimum power. The surfer may surf ‘top-to-bottom’ by speeding from the bottom of the wave to the top and visa versa, or ‘down-the-line’ by surfing diagonally across the open face of the breaking wave. By surfing ‘top-to-bottom’ the surfer may perform maneuvers such as a ‘snap’ off the lip of the wave—a sharp, sometimes 180 degree turn—or any number of aerials. A ‘rail-to-rail’ pumping motion common to modern three-fin, or ‘thruster’, surfing may be utilized to both increase speed on the open face of the wave or to pump through flat or mushy sections.
The first modern surfboards had a single center fin located towards their tails which provided lateral stability while riding down the face of the wave. By the 1970's, experimentation with two-fin, or ‘twin-fin’, surfboards had begun but they lacked lateral stability and tended to ‘track’ while transversing the wave. The three-fin ‘bonzer’ surfboard was invented and developed by Malcolm and Duncan Campbell in 1970 in Ventura, Calif. Later, the brothers expanded their design into a unique five-fin setup that incorporated a bottom contour design having a single-to-double concave extending on either side of the center line or ‘stringer’—a wooden spar running lengthwise up the middle of the board—with a single channel placed in between each pair of side ‘runner’ fins. The present three-fin, or ‘thruster’, surfboard came about in the early 1980s which incorporated two side-fins orientated near the edges, or ‘rails’, of the board on either side of the board's ‘stringer’ together with a trailing center fin orientated towards the tail. Following that, four-fin, or ‘quad’, and even five-fin designs have been used with success, offering up more opportunities for speed and experimentation in different kinds of surf. Speed is key in surfing. Speed increases the options for the rider or surfer as far as maneuvers go, whether it be launching the surfer into the air, giving him or her the option to perform a variety of aerial maneuvers, or providing the power necessary to drive through a bottom turn or perform a cutback. Speed, drive and thrust are what fuel a surfer's performance characteristics and creative and stylistic choices.
Sometimes a surfboard itself is referred to as a foil. A fin is also a foil. The fin's foil has tremendous impact on the flow of water under the board. The foil of the fin is shaped in an aerodynamic fashion from its leading edge through its trailing edge wherein the thickest portion is towards the middle while the thinnest are towards the outer edges in a teardrop fashion. The ‘if it looks right, it will fly right’ principle in aeronautics is applicable here in which if an airplane looks sleek and fast, it is thought to be more likely to fly ‘right’ or with agility, stability, speed and maneuverability. This look of speed is achieved, at least partially, by having a teardrop foil along the wings' surfaces. The teardrop foil, together with the angle of attack—the pitch angle that the wing is positioned relative to horizontal airflow—of an airplane wing creates the lift necessary for flight because, according to the Bernoulli Principle, in order to move around the foil on top of the wing the air is forced to curve and increase in speed which also creates a drop in pressure. The curved airflow creates an area of higher pressure below the airplane foil thereby creating the lift necessary for flight. Since the airflow follows the foil's curved shape a downward shift in airflow is created. This downward flow in turn creates an opposing upward force due to Newton's Third Law of Motion which states ‘every action has an equal and opposite reaction’.
Similar to air moving over an airplane wing, the laws governing fluid dynamics—specifically those relating to fluid traveling through a confined space such as a tube or channel—exhibit certain properties in common. The ‘Venturi effect’ states that as a fluid travels through a channel or tube, or other such confined space, its velocity increases through the constriction in order to satisfy the equation of continuity; as it does so its pressure must decrease to satisfy the principle of the conservation of mechanical energy. The kinetic energy gained by the increase in velocity is negated by this drop in pressure. By restricting the flow of water through the comparatively narrow way of the tube or channel, or other such confined space, this creates a vacuum effect similar to putting a thumb over one end of a garden hose with the water running. The water pressure must decrease inside the collapsed tube in order to account for the increased velocity of the water shooting out the restricted opening of the garden hose. This ‘Venturi effect’ is a jet effect.

BRIEF SUMMARY OF THE INVENTION

Disclosed herein is a design for a fin or finlike structure for use on a variety of hydrofoils and watercraft having one or more channels and flanges on its side surfaces that provide acceleration, or drive, through turns and additional speed to the craft as a whole, thereby enhancing the craft's overall maneuverability and performance. As water moves through these channels it is compressed which consequently creates a drop in pressure and generates a significant increase in speed. This patent has application to a variety of hydrofoils such as surfboards, sail boards, body boards, paddle boards, and windsurfing boards but also it will be apparent that the invention has further application to the broader field of watercraft in general.

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS

It is important to note that, for purposes of illustration, in all subsequent illustrations the fin or finlike structures are placed upside-down relative to their natural orientation in the water with the base-edge at the bottom of the illustration and the fin-tip positioned above that. It is also important to note that these illustrations represent largely hypothetical embodiments of the present invention and that further development and experimentation would be necessary before moving into production.

Reference will now be made to the accompanying illustrations which illustrate preferred embodiments of the invention, wherein:

FIG. 1A-FIG. 1F illustrate the most common channel types: round, block, slot, triangular, angular, and curved;

FIG. 2 is a side-view illustration of a single-fin having 12 graduated, round channels which are placed side-by-side symmetrically on both sides of the fin beginning at the fin's leading edge and extending through the trailing edge at a horizontal angle relative to the base edge;

FIG. 3 is a perspective-view illustration of a 3-fin, or ‘thruster’, setup having 4 graduated, round channels next to 4 flanges which begin at the leading edges, are substantially parabolic relative to the base edges extending through the trailing edges, are placed symmetrically on both sides of the trailing ‘thruster’ fin and only on the outer sides of the two side fins, the inner sides remaining flat;

FIG. 4 is a perspective-view illustration of a 3-fin, or ‘thruster’, center-fin with 3 horizontal, teardrop flanges which are placed equidistant apart symmetrically on both the foiled outer and inner side-surface;

FIG. 5 is a perspective-view illustration of a 4-fin, or ‘quad’, setup with 4 graduated, angular channels which form 4 flanges and begin at the fins' leading edges, are placed only on the convex, outer surfaces of both the larger, front side fins and the smaller, rear side fins, extending in both cases through the trailing edges at an acute angle of 2 degrees.

FIG. 6 is a straight-ahead view of the leading edge of a ‘quad’ fin with 4 graduated, angular channels placed only on the convex, outer side-surface, the inner side remaining flat.

DETAILED DESCRIPTION OF THE INVENTION

The present invention provides an alternative to present fins or finlike structures on a variety of hydrofoils and watercraft. This invention is born of a need to maximize drive while at same time minimizing drag, thereby enhancing the overall maneuverability and speed of the watercraft. Any fin or fin-like structure—be it keel, skeg, rudder, centerboard or any other structure which provides for lateral stability—serves to direct and guide the course of a hydrofoil or watercraft as it cuts through water working against changing wave, wind, and water forces and currents. When a sailboat, for example, changes course during a tacking maneuver, it is the job of the rudder to offset the keel. On a hydrofoil such as a surfboard, the number, size and shape of the fin or fins must be adjusted to both the watercraft and to the preferences of the rider in order to achieve a balance between agility, stability, speed, and maneuverability. Whereas a traditionally foiled or flat fin surface can be difficult for the rider to bank or turn to the side especially at a sharp angle—during a bottom turn or a ‘snap’ off the lip, for example—the addition of one or more channels will pipe water at increased velocity across the length of the fin or fins through these comparatively narrow ways and squeeze it out the tail-ends of the channel or channels, thereby providing for more drive and responsiveness which is particularly useful during turning maneuvers. These channels may be of any number, including one. It is a central claim of this invention that drag itself can be further reduced by the addition of one or more side channels—channels placed side-by-side, channels separated by the side surface or surfaces of the fin(s) or finlike structure(s), or channels separated by one or more flanges or convex shapes—because of how they guide and redirect water that would otherwise be lost as wasted runoff, thereby converting it into forward thrust. In addition to creating forward thrust, by increasing the acute angle of the channel or channels as measured from the intersection of the leading and base edges running through the trailing edge they in turn create lift, thereby creating a looser and more responsive ride for the surfer.
This invention may be made and used in more than one way, such as being constructed out of different materials or with different methods, or the various channels and flanges may have different applications in different areas such as boating, surfing, sailing, or wakeboarding. For example, the best process for making the a three fin, or tri-fin, setup for a modern shortboard surfboard could be to injection-mold a composite plastic determined through experimentation and design not to shatter upon impact or stress. In this example, the mold would be made to prior specifications established following a computer-aided model of the desired dimensions and shape of the fins, flange(s), and channel(s). By utilizing computer-aided design, it would be relatively easy to quickly make any minor alterations to the overall shape of the fins as well as to the dimensions and shape of the flange(s) and channels(s). The surfer could then try out and experiment with these fins with a relatively quick turn-around time from development to practical use in the field to determine which particular design features work best on a given type of wave and which design features would lend themselves to production.
An injection-molded set of fins with flanges and channels could be smaller than its exact counterpart—in terms of overall template, shape and foil—without these flanges and channels which could further serve to reduce drag. This could be so because of both the added grip provided by the edges and shape of the flanges and channels in the water. The accelerated flow of water through the channels at a given angle will both accelerate turning maneuvers and enhance maneuverability underfoot by providing additional speed.
An alternate method of producing the fin or fins would be to shape them by hand from a series of fiberglass sheets pressed together with resin providing the ‘glue’ to adhere the sheets together. This would be more time-consuming and perhaps more expensive because of the skill required to symmetrically shape the channel(s) and flange(s) but the result achieved could potentially be worth any extra effort, expense, and time in terms of durability, aesthetic, and performance. To hand-shape the channel(s) and flange(s) would require precision and skill to assure symmetry and strict adherence to the specific design of a given fin or set of fins. Since the fin or fins in this example could be made of the same materials and utilizing essentially the same method as making the outer shell of the board itself they could be more incorporated into the overall design and look of the finished board. The same sanded or gloss finish could also be maintained throughout both the board and the fin or fins. Just as the aesthetics give the fin or fins the same look and finish of the surfboard, so too could the design characteristics of the channel(s) and flange(s) on the fin or fins become an extension of the overall design of the watercraft wherein channels and concaves on the bottom of the surfboard could propel water into the channel(s) on the fin or fins themselves. This could both increase the acceleration and overall speed of the craft as a whole, and, since the channel(s) propel water out a specific angle or degree, the channel(s) could even serve to propel the craft in a preferred direction, thereby enhancing both maneuverability and performance.
A fin or finlike structure with channels separated by flanges or convex shapes is similar to a true spoiler in automobiles in terms of both appearance and function. A true spoiler is different to a rear wing in that a wing simply creates a downward force which counteracts the lift created by the airflow moving under the body of the automobile, a phenomena that increases with acceleration, thereby increasing tire traction. An automobile wing works like an upside-down airplane wing and actually creates a net negative in terms of wind drag. In order to be used effectively, a wing must create a net gain in the efficiency of tire traction which must exceed this extra drag and yield a net efficiency. Airflow follows the surface of the wing as it moves around it and this fast-moving airflow creates a pull if the other side of the automobile is subject to slower-moving air. It is the angle of attack—the pitch angle that the wing is positioned relative to horizontal airflow—that creates the amount of downward force generated by the wing but the tradeoff is that the greater the angle of attack, the more drag it creates. A spoiler is an aerodynamic device that literally ‘spoils’ the unfavorable movement of air known as turbulence which occurs when an automobile is in motion. To do this spoilers are generally placed closer to the automobile body whereas wings are placed much higher. Just as a large truck passing by a smaller car on the freeway can cause the car to wobble slightly due to the vacuum created by the differential speed of air moving in between the two vehicles and air moving around them, or how two sheets of paper will pull together when an individual blows between them due to the vacuum created by the accelerated airflow, a fin with one or more side channels on a hydrofoil such as a surfboard will similarly suck in and accelerate the flow of water through the areas of low pressure inside the channel or channels. The fast-moving water traveling through the channel or channels creates an area of low pressure that literally sucks in more water, thereby increasing overall velocity and creating an improvement in hydrodynamic efficiency which negates any additional drag due to any additional surface area created by the channels themselves. The fact that side fins, for instance, are placed at either a zero angle or are ‘toed-in’ at an acute angle to the center-line of the hydrofoil or watercraft means that the side channel or channels work with the direction of forward motion which in turn results in a further increase in speed because water is being actively pumped through the side channel or channels at a significantly increased velocity. This is particularly true during a turning maneuver because the fin or fins are placed at a more extreme diagonal angle to the direction of forward motion. The effect and benefit of one or more fins with one or more channels is immediate: the moment water flows over the side surfaces of the fin or fins and through the channel or channels it accelerates and creates a drop in pressure. Taking the example of a single fin with multiple channels, by having those channels extend at a given acute angle away from the body of the surfboard and against the downward force of gravity, the designer is able to create lift so long as those channels ensure the efficient flow of water through those channels and off the trailing edge of the fin. This does not mean that a fin with one or more channels extending at an acute angle, or different acute angles, towards the base edge would be an impractical design under the scope of this invention. An acute angle that literally points and directs the flow of water at the bottom of the hydrofoil or watercraft could similarly generate a significant increase in speed and also create lift by literally ‘bouncing’ the flow of water off the bottom of the vessel or craft itself. The potential difficulty here would be in terms of the practicality of such application and could create too loose or ‘squirrelly’ a ride for the surfer or rider.
The shape of a fin is foiled in an ‘aerodynamic’ teardrop fashion from its leading edge to its trailing edge wherein the thickest portion is towards its middle, or mid-front, while the thinnest are towards its outer edges. Depending on the placement of the fin(s) or finlike structure(s) on a hydrofoil and their configuration, the fin(s) or finlike structure(s) may be foiled on either the left side, the right side, or both. On surfboards, some fins are only foiled on one side, typically the side fins, whereas a single fin, or a center fin, is typically foiled symmetrically on both sides. Whereas side fins are known to promote the release of water and facilitate turning maneuvers, the trailing center fin's primary function is lateral stability. There are cases where asymmetrical fin placement and fin design may call for asymmetrical fin channel placement. The side ‘runner’ fins in a five-fin ‘bonzer’ setup may call for the asymmetrical placement of channels on only one side of the fins. Here again there is a tradeoff between lift and drag: the more pronounced the foil the more lift it creates which also causes the hydrofoil to slow down due to an increase in drag as compared with a thinner, more streamlined foil.
There are cases where the inside surface of a fin is concave in nature. A fin with a concave inside foil harnesses water flow from different angles, thereby increasing lift which in turn generates speed because of this increased water flow. This can be useful in weaker waves and may be contrasted with a fin with a flat inside foil which will serve to better initiate turning maneuvers and control speed in larger surf. It is for this reason that quad fins—which have had proven success in larger, steeper waves—often have flat inside foils. Further experimentation would be needed to determine the effectiveness of placing one or more channels on a concave inside foil because the channel or channels might serve at cross purposes in terms of accepting water flow from different angles.
There are also cases where the avenues or spaces between the flanges are not functional channels at all but rather are left simply the flat, concave, or traditionally foiled surface of the fin itself. In these cases, the flange or flanges serve much the same purpose as the tread on car tires in that their primary function is to ‘grip’ the wave, and they could be placed anywhere—in any configuration, shape, and number—on the side surface or surfaces of the fin or fins so long as they ensure the efficient flow of water over their side surface or surfaces and off the trailing edge(s) and, depending upon their orientation, the tail-end or tip of the fin or fins. In this sense, the ‘tread’ of the flange(s) is as important as the accelerated flow of water through the comparatively narrow way(s) of the channel(s) is in other embodiments of this invention. The ‘tread’ of the flange(s) is a design feature that could, for example, help prevent a surfer from losing traction on a larger, steeper wave.
Some surfboard shaping experts feel that in order to account for the loss of foam due to channels being cut out of the bottom of a surfboard, this loss of buoyancy must be added back somehow: by adding, for example, a ‘V’ shape to the bottom of the board. With regard to this invention, any reduction in the material used to construct the fin—fiberglass, plastic, wood, foam, carbon fiber or any other material—is actually a benefit because it reduces the weight of the craft. It has never been the function of fins to support the weight of the rider. If, in certain cases, the foil of the fin itself needs to be widened to accommodate the added width of the channel or channels and, when applicable, flanges or convex shapes, the volume removed by the channel or channels could easily be designed so as to balance out any potential added weight, thereby resulting in neutral buoyancy when compared to a fin without this added curvature and shape. Any drag that the increased curvature and surface area that such a fin may create would be negated by the compression and increased velocity of water traveling through the channel or channels.
The Coanda effect states that the flow of liquid will follow the surface it is running over. This phenomena is illustrated by putting a cup under a tap and observing how the water continues to flow on the deflected course after the end of the cup. The same phenomena is true with both a wing or a spoiler on automobiles as well as a fin with one or more channels. With a fin with one or more channels, the fast-moving water moving through the channel or channels creates an area of low pressure that literally sucks in more water, thereby accelerating the flow of water to an even greater degree. As water is sucked in, the additional drag caused by the additional surface area of the channel or channels is negated, thereby causing an overall increase in hydrodynamic efficiency. The water moving through the channel or channels will continue to accelerate in line with the channel or channels extending past the fin itself, thereby propelling the craft further in a particular desired direction.
Channels are typically more concentrated than concaves and have hard edges running along their sides that may taper off through the fin's trailing edge; these are called graduated channels. By contrast, ‘continuous depth’ channels are as their name states: channels whose depth is uniform throughout. The depth of all channels is limited by the width of the body of the fin or finlike structure and some of the embodiments of this patent may call for a widening of the fin or finlike structure itself, particularly towards the base, in order to accommodate this added width. When placed on the underside of a surfboard, channels have had the stigma that they only reach their peak functionality in clean, powerful, glassy waves and are actually an impediment in small, choppy or mushy surf. By adding one or more channels to a single fin or a series of fins, this stigma does not necessarily translate because most of these factors occur above the surface of the water. Most chop or disturbance in the water is negated by the fact that fins pierce under the surface and are not going to as significantly affect the water moving up the face of the wave itself. Furthermore, the addition of flange(s) and channel(s) could actually serve to ‘anchor’ the board in the wave itself, thereby further negating any effects of chop or disturbance in the water.

DESCRIPTION OF PREFERRED EMBODIMENTS

With reference to the drawings, and specifically with reference to FIG. 1A-FIG. 1F, the most common channel types are: round (FIG. 1A), block (FIG. 1B), slot (FIG. 1C), triangular (FIG. 1D), angular (FIG. 1E), and curved (FIG. 1F). Whereas an angular channel (15) or curved channel (16) has a definite ridge (17) inside the channel itself which can be implemented to further serve as a directional device for channeling water out at a given desired angle, a round channel (11), by comparison, provides more even distribution and flow of water throughout its width, depth, and length. As far as how, for example, triangular (14) or block (12) channels would perform when placed on the side surface or surfaces of a fin or finlike structure versus round (11) channels, all are covered under the scope of this invention and further experimentation would be necessary to determine which specific type or types of channels work best for a given fin design before moving into production.
FIG. 2 is a side-view illustration of a 7½″ single fin having 12 graduated, round channels (21) which are placed side-by-side symmetrically on both sides of the fin beginning at the fin's leading edge (22) and extending through the trailing edge (23) at a horizontal angle relative to the fin's base edge (24). The channels are each 9/16 of an inch wide and the flanges (25) are not full convex shapes but rather are more of a series of pronounced edges which extend out before tapering off with the channels to zero depth through the trailing edge (23) of the fin. The first channel begins at the base edge (24) itself. By orientating the channels at the leading edge (22) of the fin they harness much more of the runoff coming off the bottom of the hydrofoil. A fin such as this having a series of channels (21) that are more pronounced towards the fin's leading edge (22) provides edges and contours that cut, or ‘bite’, into the wave during either a turning maneuver or the ‘rail-to-rail’ pumping motion common in modern surfing. This provides additional hold which is especially useful in larger, steeper waves. The tip portion (26) is foiled symmetrically on both sides of the fin. By placing channels (21) on its side surfaces, the single fin ceases merely to provide for lateral stabilization but actually creates an overall increase in the speed of the watercraft because water that would otherwise be lost as wasted runoff is harnessed by the round channels (21) and redirected through the fin's trailing edge (23) at increased velocity. A traditionally foiled 7½″ single fin might have a base that is 5½″ to 6″. The addition of side channels (21) and flanges (25) could reduce the base edge's (24) length, thereby reducing the overall surface area of the fin significantly, and thus reducing drag. This could make for a slightly wider, more sculpted fin.
In the sport of rowing a technique referred to as ‘feather and square’ is used to gain maximum thrust with minimal drag. ‘Squaring’ the oar blade is when the rower rotates the handles so that the blade is ‘squared’ or perpendicular to the water. This is done right before the ‘catch’ or when the oar blade is placed back into the water by a slight lifting of the hands. As the oar blade is being removed from the water, the rower rotates the oar handle 90 degrees so that the blade is again parallel to the water in an action referred to as ‘feathering’. This ensures that the blade causes minimum air resistance as it is brought back over the water. FIG. 3 is a perspective illustration of a 3-fin, or ‘thruster’, setup having 4 graduated, round channels (31) next to 4 flanges (32) which begin at the leading edges (33), are substantially parabolic relative to the base edges (34) extending through the trailing edges (35), are placed symmetrically on both sides of the trailing ‘thruster’ fin and only on the outer sides of the two side fins, the inner sides (36) remaining flat. By having the channels extend through the trailing edge (35) along this parabolic curve they will similarly ‘catch’ much more of the water running off the bottom of the hydrofoil (38), water that would otherwise be lost as wasted runoff. Beginning with the channel and flange combination at the base edge (34), the depths at the leading edges (33) are as follows: ¼ of an inch deep for the channels (31) and flanges (32) towards the base (34); 3/16 of an inch for the channels (31) and flanges (32) above that; and ⅛ of an inch for the channels (31) and flanges (32) nearest the fin tip (37). All of the channels (31) and flanges (32) taper off to zero depth through the trailing edges (35) and the combined width of each channel (31) and flange (32) remains constant at an inch. In this example, the flanges (32) are a sideways ‘U’ shape with the bottom of the ‘U’ extending furtherest from the body of the fins. This ensures both proper release and traction. This could also make the fins thicker, particularly towards the base (34), to accommodate the channels (31) and flanges (32), which could make the fin more of a pivot point as opposed to a turning surface. This could also make for a smaller fin or set of fins. The advantage of having the channels (31) and flanges (32) extend along a parabolic curve relative to the base edge (34) is that the initial curve catches runoff coming off the bottom of the hydrofoil (38) the moment it passes over the fins' leading edges (33). Once this runoff passes through the channels (31) it is compressed, thereby creating a drop in pressure and causing an increase in fluid velocity. The effect of the parabolic curve of the channels is similar to the ‘feather and square’ action of the rower's stroke in that it causes minimum drag while at the same time generating maximum speed. The addition of side channels (31) also allows for a smaller fin template. When compared with a single-fin, the thruster has been described as having ‘power steering’ and has proven reliability and dependability at critical junctures on the wave when setups like a single, twin, or even a quad can be tested. By adding the 4 channel (31), 4 flange (32) setup of FIG. 3, the surfer is able to harness and generate more speed and greater maneuverability when surfing either ‘down-the-line’ across the open face of the wave, or the ‘rail-to-rail’ pumping motion associated with thruster surfing which is particularly useful in either flat or mushy surf. This makes the hydrofoil faster in terms of velocity ‘down-the-line’ and quicker meaning more responsive during turning maneuvers and when the rider shifts his or her weight.
The center-fin of a three-fin, or ‘thruster’, setup provide an opportunity to present an example of flanges (41) placed by themselves without any channels separating them on both the foiled outer and inner side surfaces. The flanges (41) can be any convex, hydrodynamic shape, and be placed anywhere on the foiled, flat, or concave outer or inner side surface or surfaces. FIG. 4 is a perspective-view illustration of a 3-fin, or ‘thruster’, center-fin with 3 teardrop flanges (41) placed symmetrically on either side-surface which extend horizontally and are equidistant apart towards the tip portion (42). The flanges begin at the leading edge (43) on each side-surface and their shapes are elongated teardrops extending towards the trailing edge (44). In this example, the flanges (41) serve the same purpose as tread on automobile tires in that they provide traction, or grip, on the wave.
A four-fin, or ‘quad’, setup offers several benefits over a traditional three-fin, or ‘thruster’, setup. Quad setups are sometimes thought to be faster and, because the two pairs of fins work in tandem together on the rail, the additional fins do not actually create more drag when compared with a ‘thruster’ even with the additional surface area. The heightened responsiveness comes from the fact that quad fins are set further up the board, closer to the central axis and under the rider's back foot. This makes the rider's input more immediate and direct. Whereas the ‘thruster’ setup offers drive, agility and speed in a variety of wave conditions, the absence of a center fin is thought by some to provide an even faster and more responsive ride and perhaps better performance in larger surf. The quad ‘gun’, a big-wave board, offers both the stability and drive to charge through ‘boils’ (the up-welling of the water off the reef as the wave passes over), troughs and choppy conditions in this large, fast-moving and unpredictable surf. FIG. 5 illustrates a ‘quad’ fin setup with 4 graduated, angular channels (51) which form 4 flanges (52) and begin at the fins' leading edges (53), are placed only on the convex, outer surfaces of both the larger, front side fins and the smaller, rear side fins, extending in both cases through the trailing edges (54) at an acute angle of 2 degrees. The sharp, 90 degree wedges (55) of the 4 graduated channels (51) actually form the flanges (52) and determine their shape. In this example, the inner sides (56) of both the front and rear side fins remain flat which promotes the release of water allowing for more pronounced, extreme turns which is especially useful in the face of the wave. At the leading edges (53), the channels (51) are ¼ of an inch deep at the base (57), 3/16 of an inch for the two above that, and ⅛ of an inch for the one at the tip, tapering off to a depth of around 1/16 of an inch through the trailing edges (54). The tip portions (58) are left foiled normally on the outer sides and flat on the inner sides (56). As a result of these angular channels (51), the fins would actually generate a net increase in speed, and could allow for an even smaller set of fins and therefore provide for an even more responsive ride with increased stability when compared to their larger, traditionally foiled counterparts which is especially useful in larger surf. Smaller fins also help avoid getting the fins snagged in seaweed, kelp or debris. Similar to twin fins, the angle of attack of these toed-in quad fins causes a significant decrease in water pressure on the outer surfaces of the fins and also a continual inflow of water throughout the entire length of these comparatively narrow ways at an even greater velocity than the already fast-moving water moving over their outer surfaces. With four channeled fins in the water the rider may more fully commit to a bottom turn, and, as the angle of attack increases, the rider is less likely to ‘spin out’ due to a loss of traction or an air pocket. FIG. 6 is a head-on view of the leading edge of a quad fin with 4 angular channels. The flanges (52) cut into the water flowing over the outer side surfaces of the fins both when surfing ‘down-the-line’, during turning maneuvers, and whilst surfing ‘top-to-bottom’. Water that would be lost as wasted runoff is subsequently redirected and harnessed as forward thrust. The turning motion utilizes these channels (51) further by placing the fins at a diagonal which exposes these channels (51) to a continual inflow of water similar to a ‘twin’ fin. During a turning maneuver a surfboard having fins with channels (51) would appear to have ‘power steering’ due to this increase in speed and responsiveness. It should be noted here, however, that increasing the toe of side-fins produces a similar effect to increasing the angle of attack of an airplane wing in that the greater the angle of the wing from horizontal, or the front of the four fins in towards the center line or ‘stringer’ (59) of a hydrofoil, the more lift is created but also the more drag. A greater angle will produce more lift but it also creates more drag which slows the board down similar to flaps on airplane wings when they are angled upwardly. For a ‘quad’ surfboard having fins with side channels (51) an effective balance must be struck between lift and drag as determined by the ocean conditions, the types of waves being ridden, and the skill and ability of the rider. With the added hold provided by these channels (51) and flanges (52), the rider experiences a more comfortable and controlled ride while at the same time remaining more maneuverable and agile due to the decrease in size. The rider then finds him or herself not forcing the maneuvers he or she is attempting. The reason the angles of the channels (51) are less pronounced for both twin fins and quad fins is that they serve the same purpose as the toed-in angles of the fins themselves: both create lift and having the channel or channels (51) extend at too extreme an angle could create too loose and uncontrollable a ride for the surfer or be rendered ineffective in terms of harnessing runoff coming off any concaves and channels on the bottom of the board.
While the preferred embodiments represented by the illustrations of the present invention have been described, it is to be understood that modifications other than those specifically described herein can be made and that other embodiments may be devised without departing from the spirit of the invention and the scope of the appended claims.

Claims

What is claimed is:

1. A fin or finlike structure having both a leading edge and a trailing edge which meet to define a fin tip, a base having a base edge that connects to a hydrofoil or watercraft, said fin or finlike structure including:

a channel or channels placed on one or both side surfaces.

2. A fin or finlike structure as claimed in claim 1, wherein said channel or channels are of any size and shape so long as those characteristics ensure the flow of water through said channel or channels and off said trailing edge and, depending upon their orientation, said fin tip.

3. A fin or finlike structure as claimed in claim 1, wherein said channel or channels are of any type including but not limited to: round, square, block, slot, triangular, angular, and curved.

4. A fin or finlike structure as claimed in claim 1, wherein said channel or channels are placed anywhere latitudinally and anywhere longitudinally on the side-surface or surfaces of said fin or finlike structure.

5. A fin or finlike structure as claimed in claim 1, wherein said channels are placed side-by-side.

6. A fin or finlike structure as claimed in claim 1, wherein said channels are separated by either the foiled or flat side-surface or surfaces.

7. A fin or finlike structure as claimed in claim 1, wherein said channels are separated by one or more flange(s) or convex shape(s).

8. A fin or finlike structure as claimed in claim 7, wherein said flange(s) or convex shape(s) are of any number, size, and shape so long as those characteristics ensure the flow of water through said channel or channels and off said trailing edge and, depending upon their orientation, said fin tip.

9. A fin or finlike structure having both a leading edge and a trailing edge which meet to define a fin tip, a base having a base edge that connects to a hydrofoil or watercraft, said fin or finlike structure including:

one of more flange(s) or convex shape(s) separated by either the foiled, concave, or flat side-surface or surfaces.

10. A fin or finlike structure as claimed in claim 9, wherein said flange(s) or convex shape(s) are of any number, size, and shape so long as those characteristics ensure the flow of water around and over said flange(s) or convex shape(s) and off said trailing edge and, depending upon their orientation, said fin tip.

11. A fin or finlike structure as claimed in claim 1, wherein the spacing in between said channels is uniform.

12. A fin or finlike structure as claimed in claim 1, wherein the spacing in between said channels is not uniform.

13. A fin or finlike structure as claimed in claim 1, wherein said channel or channels extend at a horizontal angle.

14. A fin or finlike structure as claimed in claim 1, wherein said channel or channels extend at an acute angle as measured from the intersection of said leading and base edges.

15. A fin or finlike structure as claimed in claim 1, wherein said channels extend at different acute angles as measured from the intersection of said leading and base edges.

16. A fin or finlike structure as claimed in claim 1, wherein the lengths of said channels are the same.

17. A fin or finlike structure as claimed in claim 1, wherein the lengths of said channels are not the same.

18. A fin or finlike structure as claimed in claim 1, wherein the depth(s) of said channel or channels is/are uniform throughout its or their length, respectively.

19. A fin or finlike structure as claimed in claim 1, wherein the depth(s) of said channel or channels gradually decrease(s) through the trailing edge.

20. A fin or finlike structure as claimed in claim 1, wherein the width(s) of said channel or channels is/are uniform throughout its or their length, respectively.

21. A fin or finlike structure as claimed in claim 1, wherein the width(s) of said channel or channels is/are not uniform throughout its or their length, respectively.

22. A fin or finlike structure as claimed in claim 1, wherein the width(s) of said channel or channels get(s) wider throughout its or their length, respectively.

23. A fin or finlike structure as claimed in claim 1, wherein the width(s) of said channel or channels get(s) narrower throughout its or their length, respectively.

24. A fin or finlike structure as claimed in claim 1, wherein said channel or channels is/are straight.

25. A fin or finlike structure as claimed in claim 1, wherein said channel or channels is/are not straight.

26. A fin or finlike structure as claimed in claim 1, wherein the curvature of said channel or channels remains constant throughout its or their length, respectively.

27. A fin or finlike structure as claimed in claim 1, wherein the curvature of said channel or channels progressively decrease(s) throughout its or their length, respectively.

28. A fin or finlike structure as claimed in claim 27, wherein said curvature of said channel or channels is/are substantially parabolic in shape relative to said base edge.

29. A fin or finlike structure as claimed in claim 1, wherein said channel or channels is/are initially curved towards the intersection of said leading and base edges before following a straight path.

30. A fin or finlike structure as claimed in claim 1, wherein said channels are symmetrical on either side surface.

31. A fin or finlike structure as claimed in claim 1, wherein said channels are not symmetrical on either side surface.

32. A fin or finlike structure as claimed in claim 1, wherein said hydrofoil or watercraft is a surfboard, windsurfing board, sailboard, paddle board, body board, wakeboard, waterski, boat, sailboat, catamaran, water scooter, jet ski, wave runner, yacht, submarine, and any and all other wholly or partially submerged vessels or vehicles.