[0001 ] The present invention relates to a surfboard comprising deep channels in the bottom contour reducing the overall planing surface and associated drag, and to create vortices and increase water pressure through the channels to generate forward thrust and improve the down the line speed of the surfboard as it travels on a wave.

Background Art

[0002] The following discussion of the background art is intended to facilitate an understanding of the present invention only. The discussion is not an acknowledgement or admission that any of the material referred to is or was part of the common general knowledge as at the priority date of the application.

[0003] A surfboard, stand-up paddleboard (SUP), or similar type of board for use in water sports and other activities can be viewed in one sense as a summation of hydrodynamic surfaces. The surface of the bottom of the board, known as the bottom contour, in contact with water generates lift and affects speed. In addition, the fins working in collaboration with rail and bottom contour surfaces influence the feel of the board when changing direction.

[0004] The modification of the surface of the bottom contour and rails has been the focus of surfboard shapers for decades to improve lift, speed, control, and other factors. However, in most cases, changes to the shape of bottom contours and the effects they provide has been relatively subtle due to the use of foam blanks of common shapes, and similar shaping tools and techniques which have been passed down from one shaper to another. [0005] Shapers since the 1970's (before that just Greg Noll in 1965 and 1966 with his two-shallowed groove 'Slot Bottom' design) have incorporated channels of a variety of shapes and configurations into the bottom contours of their boards. These channels range from very slight, usually single or double concaved surfaces, through to deep grooves usually towards the tail of the bottom contour but also in the mid-section. Some common channels are typically triangular in overall shape as they are formed in the foam of the bottom contour to create flat surfaces on different planes which terminate at the tail of the board. Other more unique channel designs include Erie Pederson's custom 'Jet Bottom' comprising an arrangement of curved criss-crossing and interconnecting channels to reduce water tension and improve performance in weaker waves.

[0006] The general theory around channels in the bottom contour of surf boards is that they provide additional 'grip' (i.e. stability) and speed to the surfboard down the line to increase performance by influencing water flow under the board. The faces of the channels provide added surface to push against for drive through turns, and by removing a portion of the bottom curve, they create straight line drive. In this respect, the channels increase the wetted surface area providing additional lift, and create small corridors of increased rocker providing more release for the water passing along the bottom of the board. Vertical walls created by the channels also provide a level of resistance that can allow for smaller fins to be used.

[0007] The present invention attempts to develop further advantages during surfing from altering the bottom contour of a surfboard.

Summary of the Invention

[0008] The present invention provides a surfboard comprising: a deck and a bottom contour meeting between a nose and a tail at a leftside rail and at a right-side rail; at least one channel in the bottom contour, left-side rail, and/or right-side rail, the at least one channel comprising an elongated concave groove; and the at least one channel comprising rifling, wherein the rifling comprises at least one elongated rifling rib and/or at least one rifling groove. [0009] In a preferred embodiment of the invention, the at least one channel comprises a plurality of elongated rifling ribs and/or rifling grooves. A rifling groove may be formed by the valley created between two rifling ribs. The at least one rifling rib is preferably a spiralling rib, and/or the at least one rifling groove is preferably a spiralling groove. The spiralling rib(s) and/or spiralling groove(s) may be at a variety of angles. These angled rifling rib(s) and/or rifling groove(s) assist to cause water passing through the at least one channel to spiral in the direction of the rifling.

[0010] The shape of the at least one channel may vary along the elongated length of the channel. Preferably, at least a portion of the at least one channel comprises a semi-closed cross-section. More preferably, the semi-closed cross- section comprises a major arc of a circle, or at least a major arc of a substantial circle shape, which assists to maintain spiralling water within the channel but also enables water forced off an adjacent planing surface of the bottom contour to enter the channel. The maximum depth of the channels preferably range from between approximately 1 cm to 10 cm. More preferably, the maximum depth of the channels ranges from between approximately 3 cm to 6 cm.

[001 1 ] In one embodiment, rifling in a channel located in the bottom contour on the left side or in the left-side rail of the surfboard will preferably cause water passing through the channel to spiral in a clockwise direction, and rifling in a channel located in the bottom contour on the right side or in the right-side rail of the surfboard will preferably cause water passing through the channel to spiral in an anti-clockwise direction.

[0012] The channel or channels preferably comprise rifling ribs or another attachment or configuration which can direct water flowing through the channels to spiral. The rifling ribs may comprise a variety of different shapes and configurations. In a preferred embodiment, elongated rifling ribs comprise a cross-sectional shape of a: triangle, square, rectangle, rhomboid, trapezoid, diamond, diamond comprising concaved sides, and/or caudal peduncle keel. The size and/or shape of the at least one elongated rifling rib may or may not change along the elongated length of the rib. The rifling ribs in a channel may comprise different shaped rifling ribs with different cross-sectional shapes and configurations. A rifling rib in a channel may comprise a cross-section of different heights, sizes and/or shapes at different locations along the length of the elongated rifling rib. In one non-limiting example, a rifling rib may taper off and reduce in height and size toward the end of a channel or towards the end of the rib. Rifling ribs and grooves may extend all the way along the length of a channel or may only extend along portions of a channel. Rifling ribs and grooves may extend within different portions of a channel with no rifling ribs or grooves in between these portions but a flat inner channel surface. Rifling ribs and grooves may start at the beginning of a channel or they may start part way along a channel. Rifling ribs and grooves may end at the end of a channel or end before the end of the channel. The angle of the rifling ribs may vary. Preferably, the rifling ribs are on an angle within the length of the channel of between approximately 1 degree to 89 degrees measured against the longitudinal length of the channel, more preferably between approximately 20 degrees to 70 degrees, and even more preferably between 30 degrees and 60 degrees. Different rifling ribs within a channel and between channels in a board may be positioned at different angles or at the same angle and the angle may change along the length of a rifling rib or groove or stay the same angle.

[0013] In a preferred embodiment of the invention, the bottom contour comprises two or more planing surfaces, and preferably, multiple planing surfaces. Some or all of the planing surfaces are preferably substantially flat or comprise a slight curve. A channel is preferably located between planing surfaces unless it is in a rail where it will be preferably located next to one planing surface. Preferably, a planing surface in the bottom contour is located on an angle that causes water to be directed into an adjacent channel when the surfboard is ridden on a wave. This would assist to increase the amount, and therefore, concentration and pressure of water in the channel and speed of the spiralling water. The faster the spiralling water in the channel, the higher the pressure created in the channel as it moves towards the tail of the board. The pressure differential between the spiralling higher water pressure towards the rear of the channel near the tail compared to the lower pressure at the front of the channel near the nose creates lift and therefore, thrust in a forward direction towards the area of lower pressure, increasing the forward speed of the board on the wave.

[0014] The shape of the at least one channel is preferably straight or curved. The direction of the at least one channel is preferably substantially aligned with, or substantially parallel to, the centre line (or stringer) of the surfboard between nose and tail, or in substantial alignment with the left-side rail or right-side rail.

[0015] In a preferred embodiment, a left-side rail channel is located in or adjacent the left-side rail, and a right-side rail channel is located in or adjacent the right-side rail. Preferably, the left-side rail channel and right-side channel comprise elongated concave grooves in the rails.

[0016] In a preferred embodiment, a left-side centre channel is located adjacent a right-side centre channel, on either side of, and substantially parallel to, the centreline of the surfboard (or stringer) between nose and tail. [0017] In a preferred embodiment, a left-side medial channel is located in the bottom contour between the left-side rail channel and left-side centre channel, and a right-side medial channel is located in the bottom contour between the right-side rail channel and right-side centre channel. In one embodiment, the left-side medial channel and right-side medial channel comprise a squared portion adjacent the end of the channel nearest the nose.

[0018] A portion of the left-side centre channel and a portion of the right-side centre channel preferably meet at a centre edge on or along the centreline of the surfboard between nose and tail, and the surfboard comprises a centre fin extending from the centre edge, and preferably, located approximately equidistant between nose and tail. The centre fin preferably comprises at least two sides comprising concave portions. The concave portions preferably comprise at least one rifling rib and/or at least on rifling groove, and more preferably comprise a plurality of rifling ribs and/or rifling grooves.

[0019] The centre fin preferably comprises an inner conduit with an opening at the nose-end of the centre fin through which water can enter, and openings into the left-side centre channel and right-side centre channel through which water can exit. This serves to force additional water into the centre channels, preferably in the direction of the already spiralling water to increase the speed of the spiralling water further. [0020] The tail, rails and nose of the surfboard may comprise a variety of conventional configurations and shapes. In one, non-limiting example, the tail of the surfboard is a swallow tail.

[0021 ] In an alternative embodiment, the surfboard according to the invention as described herein does not comprise rifling in the at least one channel. [0022] Process for Manufacturing a Surfboard of the Invention

[0023] The present invention further provides a process of manufacturing a surfboard of the invention as herein described. Materials used to manufacture the surfboard of the invention may include materials used in conventional surfboard construction including, amongst others, foam and fiberglass, and/or other epoxy resins.

[0024] Rifling ribs may be formed during construction of channels during construction of the surfboard. Alternatively, and more preferably, channel attachment portions comprising rifling are constructed separately, and are then attached within channels of the surfboard of the invention during manufacture of the surfboard. Thus, the invention further provides a surfboard as described herein, wherein one or more channel attachment portions comprising the rifling are attached within the at least one channel during manufacture of the surfboard.

[0025] In another embodiment, the invention provides a channel attachment portion, comprising rifling as described herein (or without rifling), for incorporating into the bottom contour and/or rails of a surfboard during manufacture of the surfboard, including a surfboard as described herein. The channel attachment portions, comprising rifling as described herein, may be constructed from fibreglass, plastic, resin, moulding, or another suitable material. The channel attachment portions may range in length from almost the length of a surfboard from nose to tail, through to small, preferably, at least 10 cm long portions for inserting into a channel. The channel attachment portions may be straight or curved along its length. The material forming the channel attachment portions is preferably between approximately 2 mm to 15 mm thick (excluding the additional width of rifling ribs), more preferably, between approximately 3 mm to 8 mm thick. The rifling ribs are preferably between approximately 0.5 mm to 15 mm high, more preferably between approximately 1 mm to 10 mm high, and rifling grooves are similarly deep. The channel attachment pieces preferably comprise an open elongate circle, open seamed tube, or major arc (i.e. greater than a semi-circle or 180 degrees).

[0026] Due to the unique configuration of the bottom contour of the surfboard of the invention, the surfboard may be shaped or cut using an available laser cutting process and/or device, or may be produced in a mould. Alternatively, the bottom contour could be shaped using traditional means by a shaper. Channel attachment portions could then be attached in place to complete the surfboard of the invention.

[0027] Without wanting to be limited by theory, the inventor understands that the surfboard of the invention incorporates up to three cooperating features which can lead to an increase in forward or 'down the line' speed of the surfboard on a wave when compared with the common surfboard shapes currently available.

[0028] A common surfboard shape comprises a large bottom planing surface in contact with the water on a wave. The channels in the bottom portion of the surfboard of the invention therefore create a first feature of multiple planing surfaces which: (i) reduces the surface area of board in contact with the water, and since the less board that is in contact with the water, proportionately less drag is incurred thereby allowing greater speeds; and (ii) are angled causing water to plane off the surface in a direction toward the rear of the board and also towards an adjacent channel so that some of that water is directed into a channel. [0029] The channels comprise the second feature, through which water enters from a front opening, but also, importantly, is directed into each open channel off an adjacent, angled, planing surface. In addition, rifling comprising ribs and grooves are located within each channel. Water passing through these rifling grooves is directed to spiral within the channel. Water directed off an adjacent, angled, planing surface into the channel assists the rifling to spiral all of the water passing through and out of the channel in the same direction. The spiralling creates a vortex, which in turn causes more water to be drawn into the channel. The result is an ever-increasing volume and therefore increasing pressure of spiralling water in the channel with decreasing distance towards the rear or tail of the board, when compared to the pressure of water entering the opening at the front of each channel. This pressure differential generates 'lift' and translates to a mild to moderate thrust in the direction towards the area of lower pressure and therefore adds speed to the surfboard in a forward direction on the wave when compared to the speed of a conventional surfboard of equivalent dimensions on the same wave.

[0030] From an observation point in front of the surfboard as it rides a wave, channels on the right side of the surfboard will spiral water in an anti-clockwise direction, and channels on the left side of the board will spiral water in a clockwise direction.

[0031 ] Narrow surfboard templates with narrow tails, cause drag and suction, and are inherently unstable and interfere with the ideal planing process. In contrast, the vortices exiting the rear openings of the channels in combination with the wide and irregular configuration of the tail of the surfboard of the invention, disrupts the water in this region to further reduce drag and suction from the water passing this region of the board.

[0032] A third feature is the configuration of the centre fin which comprises a cross-sectional shape similar to that of a caudal peduncle with a caudal keel (lateral ridge) which also resembles a diamond shape with concave curved sides. Some fast fish and sharks have relatively oblique caudal peduncle keels located anterior to the caudal fin on either side of the caudal peduncle. These keels converge caudally and accelerate the flow of water between them and thereby direct a high-velocity jet of water across the middle of the caudal fin. This causes a pressure drop along the middle of the caudal fin and reduces slippage of the boundary layer and consequent turbulence toward the tips of the fin, therein reducing drag and contributing to lift forces at the keel, which provides stability and support to the caudal fin. In imitation, the caudal peduncle keel shaped centre fin on the surfboard of the invention creates vortices either sides of the lateral 'keel', assisted by rifling ribs on the fin to similarly reduce drag and increase lift. In addition, water is directed from the upper surfaces of the fin above the lateral keel into the centre channels to further increase the water pressure in these channels.

[0033] Importantly, reference herein to a 'surfboard' is to also include many other types of boards, hulls of, for example, boats and yachts, and water, underwater, and amphibious vehicles, used in surface water sports or used to travel on the surface of water, on a wave, or under the water. Such other types of boards, etc, include, in some non-limiting examples, shortboard, kneeboard, longboard, minimal, soft board, kiteboard or a board used for kite surfing, wind surfer, stand up paddleboard, wakeboard, rescue board, bodyboard, or another board used in surface water sports or activities. All of these boards, hulls, vehicles are included because they may take advantage of the additional speed from reduced drag/increased thrust that may be provided by the configuration, or a similar or equivalent configuration, or aspects of the configuration, of the bottom contour of the surfboard of the invention as herein described. Thus, features of the bottom contour and rails as herein described with reference to a surfboard, may also be incorporated into the outer, water-contacting surface of another board or watercraft that travels on or below the water, whether powered by the waves, another natural means such as wind, or by mechanical means.

Brief Description of Drawings [0034] The present invention will now be described, by way of example, with reference to the accompanying drawings, in which: an illustration of an (A) top view, (B) bottom view, (C) front view, and (D) side view, of a preferred embodiment of a surfboard of the invention. an illustration of an (A) bottom perspective view, and (B) a partial bottom view, of a preferred embodiment of a surfboard of the invention. an illustration of an (A) bottom perspective view, and (B) a partial bottom view, of a preferred embodiment of centre channel attachment portions comprising an alternative rifling rib cross- sectional configuration. an illustration of an (A) bottom perspective view, (B) top view, (C) partial bottom perspective view, and (D) front view, of a preferred embodiment of centre channel attachment portions comprising an alternative rifling rib cross-sectional configuration. an illustration of an (A) partial front perspective view, (B) a partial bottom perspective view, and (C) a partial rear perspective view, of a preferred embodiment of a surfboard of the invention. an illustration of an (A) perspective front view, and (B) a partial side perspective view, of a preferred embodiment of a surfboard of the invention. an illustration of an (A) partial rear perspective view, and (B) side perspective view, of a preferred embodiment of a surfboard of the invention. an illustration of an (A) partial front view, and (B) rear perspective view, of a preferred embodiment of a surfboard of the invention.

Description of Preferred Embodiments [0035] Those skilled in the art will appreciate that the invention described herein is susceptible to variations and modifications other than those specifically described. It is to be understood that the invention includes all such variations and modifications. The invention also includes all of the steps, features, compositions and compounds referred to or indicated in the specification, individually or collectively and any and all combinations or any two or more of the steps or features.

[0036] The present invention is not to be limited in scope by the specific embodiments described herein, which are intended for the purpose of exemplification only. Functionally equivalent products, compositions and methods are clearly within the scope of the invention as described herein.

[0037] Throughout this specification, unless the context requires otherwise, the word "comprise", or variations such as "comprises" or "comprising", will be understood to imply the inclusion of a stated integer or group of integers but not the exclusion of any other integer or group of integers.

[0038] Other definitions for selected terms used herein may be found within the detailed description of the invention and apply throughout. Unless otherwise defined, all other scientific and technical terms used herein have the same meaning as commonly understood to one of ordinary skill in the art to which the invention belongs.

[0039] Features of the invention will now be discussed with reference to the following preferred embodiments.

[0040] A preferred embodiment of a surfboard according to the invention is shown in Figure 1 . The surfboard comprises a substantially planar deck surface 10 on which the surfboard is ridden by a surfer in a conventional manner, with a nose 12 at the front end, a left rail 14 along the left side and a right rail along the right side 15 (from a perspective of viewing the surfboard from the nose 12, i.e. from the front), and a swallow tail 16. Although other configurations of the nose, tail, and rail edges may also be incorporated into the surfboard of the invention. A centre line 18 is also depicted in Figure 1 A, though this may or may not indicate the presence of a centre stringer. The rear of the centre fin 20 is also visible from the rear of the surfboard 10.

[0041 ] Rather than the substantially planar bottom contour with subtle curves common to conventional surfboards, the bottom contour 30 of the surfboard of the invention shown in Figure 1 B and Figure 1 C is unique in that it comprises multiple planing surfaces 32 which are for planing over the water on a wave, channels 40 with rifling ribs 50, and a caudal peduncle keel shaped centre fin 60.

[0042] The channels 40 in the bottom contour 30 comprise predominantly elongated concave grooves extending for at least a portion of the bottom contour 30 in a generally straight or slightly curved direction between nose 12 and tail 16. The channels 40 serve two key purposes. The first key purpose is to spiral water passing through the channels 40 with assistance of the rifling ribs 50 to create a vortex which in turn causes more water to be drawn into each channel 40. The result is an ever-increasing volume of spiralling water and therefore water pressure in each channel 40 with decreasing distance towards the rear or tail of the board when compared to the pressure of the water entering the opening at the front of the channel 40.

[0043] The second key purpose for the channels 40 is that it reduces the overall planing surface of the bottom contour 30 in contact with the surface of the wave that the surfboard of the invention is ridden on (when compared to conventional surfboards of a similar dimensions). A reduction in overall planing surface reduces the drag potential from water in the wave therein enabling a net increase in velocity from the reduction in drag, when compared to a surfboard of similar dimensions without such channels.

[0044] The surfboard of the preferred embodiment of the invention comprises three sets of two channels on either side of the surfboard as shown in Figure 2. A set of two centre channels 42 either side of the centre line 18 have front openings 43 adjacent the nose 12 and rear openings 44 adjacent the tail 16. The centre channels 42 comprise elongated concave grooves through to elongated partial cylinders open along their length. [0045] Each centre channel 42 comprises four sets of rifling ribs 50 within the inner circumference of the partial cylinders open along their length. The rifling ribs 50 are attached to channel attachment portions 52 which are inserted into the channels during manufacture for ease of production. The channel attachment portions 52 fit within grooves in each channel so that only the rifling ribs 50 extend into the channels to affect the flow of water passing through the channel. Rifling grooves 54 are formed between rifling ribs 50 which cause water passing through the rifling grooves 54 to spiral.

[0046] Figures 3 and 4 show a pair of centre channel attachment portions 52 which can be manufactured separately, and then inserted and attached into channels in the manufacture or completion of a surfboard according to the invention as described herein. The configuration of the rifling ribs 50 in Figures 3 and 4 show an alternative embodiment to the substantially triangular rifling ribs 50 of Figures 1 and 2. Instead, the rifling ribs 50 of Figure 3 have a cross- section with similarities to that of the cross-section of a caudal peduncle keel of a fast fish (e.g. tuna) or shark as can be more easily viewed in Figure 3B. This caudal peduncle keel-like cross-section comprises a diamond-like shape with concave curves instead of straight sides between points or 'corners' of the diamond, and a flat base surface at the point which contacts the inner surface 53 of the channel attachment portion 52.

[0047] Without wanting to be limited any theory, it is understood that vortices are created between at least the inner surface 53 of the channel attachment portion 52 and the closest concave sides 55 of the caudal peduncle keel-like shaped rifling ribs 50. These vortices are created from water moving along the inner surface 53 of the channel attachment portion 52 and contacting a rifling rib 50 which forces the water up the curved concave side 55 of the rifling rib 50. The curved shape of the rifling rib 50 causes the water to fall back on itself in a substantially circular or 'barrelling' motion as it leaves the side point 57 of the rifling rib 50 forming a vortex adjacent to where the rifling rib 50 and inner surface 53 of the channel attachment portion 52 meet along the length of the rifling rib. These vortices created along the rifling ribs generate a region of lower water pressure drawing more water into the front of the channel which then can traverse the channel at a faster rate due to these small vortices at the base of the rifling ribs reducing water tension and drag.

[0048] The sides of the centre channels 42 closer to the centre of the surfboard meet along a centre edge 49 of the board. They also meet to form the base of the caudal peduncle keel shape of the centre fin 60 (Figure 5).

[0049] The centre fin 60 extends from the centre edge 49 approximately equidistant between nose 12 and tail 16 and comprises a tail portion 62 that does not connect the bottom contour 30 of the surfboard but extends beyond the tail 16. Two sets of rifling ribs 50 are present on each fin side surface which assist to direct water off the caudal peduncle shaped fin to form vortices either side of the fin.

[0050] A centre fin front opening 64 provides entry for water to pass through a conduit and exit at centre fin rear openings 66 into both centre channels 42 thereby forcing more water into the centre channels 42 in a direction to add to the already spiralling water (Figure 6).

[0051 ] Outer channels 48 of elongated concave grooves are formed in the rails 14,15 where the rails 14,1 5 meet the bottom contour 30 and these outer channels 48 do not start as close to the nose 12, or end as close to the tail 16, as the centre channels 42 (Figure 7). The outer channels 48 each comprise four sets of rifling ribs 50 on separate channel attachment portions 52. The outer channels 48 are more curved as they follow each rail 14,15 than the straighter centre channels 42.

[0052] Median channels 46 are located between each centre channel 42 and outer channel 48 (Figure 8). The median channels 46 comprise 'squared' shaped channels in a front portion which become elongated partial cylinders comprising three sets of rifling ribs 50, towards the tail 16 of the board. Figure 8 also shows the angles of the adjacent planing surfaces 32 directing water into the adjacent channels.

[0053] From a perspective of viewing the surfboard from the nose 12, the angle and configuration of the rifling ribs 50 in channels 40 on the right side of the surfboard will cause water passing through the channels to spiral in an anticlockwise direction, and the angle and configuration of rifling ribs 50 in channels 40 on the left side of the board will cause water passing through the channels to spiral in a clockwise direction. [0054] In addition to reducing the overall planing surface to reduce drag, the multiple planing surfaces 32 in the bottom contour 30 between channels 40 also provide another important role. The multiple planing surfaces 32 are angled to direct the layer of water in contact with the planing surface 32 (in the laminar flow of water drawn up the wave face) towards the adjacent channel 40 (as can be seen, for example in Figure 8).

[0055] The vortex created from the water spiralling within the channel will also assist to draw some of this water off the planing surface and into the channel to join the vortex. Thus, more and more water is drawn into the channel towards the rear of the channel naturally increasing the water pressure with decreasing distance to the tail of the surfboard. The pressure differential between the higher water pressure in the channels towards the tail of the surfboard compared to the lower water pressure towards the front of the channels near the nose 12 of the surfboard will result in lift, or thrust in a direction towards the area of low pressure. While the additional thrust created will be mild to moderate, in combination with the reduced drag provided by the reduced planing surface, it provides a net gain in the forward velocity of the surfboard of the invention on a wave when compared to a conventional surfboard of similar dimensions.