GB2476532A

GB2476532A - A water sports board with longitudinally extending spines

Info

Publication number: GB2476532A
Application number: GB1017833A
Authority: GB
Inventors: Mike Titley; Peter Bladd-Symms
Original assignee: Envisor Ltd
Current assignee: Envisor Ltd
Priority date: 2010-10-21
Filing date: 2010-10-21
Publication date: 2011-06-29
Anticipated expiration: 2030-10-21
Also published as: WO2012052741A4; GB2476532B; GB201017833D0; WO2012052741A1

Abstract

A water sports board has a front section 1, mid section 3 and rear section 5, where the mid section has a generally flat underface and a high volume compared to conventional surfboards. The rear section has a plurality of elongate spines 13 and 15 protruding from its underside which have their length in a longitudinal direction of the board and a depth that is less than their length. The spines define between them and the underside of the board one or more channels 19, whose depth increases from front to rear of the board, the channels having a width greater than their depth. The thickness of the rails 21 in the rear section of the board is reduced compared to the mid section in order to provide the board with good turning ability, despite the additional volume of the board. Two, three, four or more longitudinally extending spines may be provided and a longitudinally extending ridge 23 may also be provided at the centre underside of the front section to assist longitudinal stability of the board.

Description

BOARD-TYPE WATERCRAF1T The present invention relates to a board-type watercraft such as a surfboard, windsurfer, kite board or stand-up paddleboard, and in particular to a surfboard targeted at riders of beginner or intermediate standard and which is easier to ride especially in shallow and/or broken water. The invention can also be applied to stand-up paddleboards, that is to say boards which are larger than modem surfboards and on which the rider stands and paddles with an oar.

Surfboards are familiar as elongate, buoyant boards designed to be propelled on water by waves under the control of a rider who stands on the surfboard with one foot towards the rear and one towards the middle. The board is controlled by weight transference and by tilting the board laterally ("carving") which allows the board to turn and be ridden along the wave. Surfboards are believed to have originated in Hawaii where they were made from wood and were very large and heavy, often over 15 feet (5 metres) in length. Surfboard construction and design were revolutionised through the twentieth century with boards becoming shorter and lighter, made from polyurethane or polystyrene foam covered with layers of fibreglass and polyester or epoxy resin. Since the I 960s there have been many developments and changes in design aimed at providing different compromises between stability, ease of use, manoeuvrability and speed for different types of rider in different types of surf A relatively conventional modem surfboard, such as the Malibu, which is one of a class of boards known as longboards, is normally 9 feet (2.7metres) or more in length, 21 to 23.5 inches (-53-60 cm) wide and 2-3 inches (50 to 75mm) thick. It normally has one, two or three fins fitted to the underside of the rear of the board to provide improved grip on the water and improved directional stability. Boards are also conventionally provided with a certain amount of "rocker", that is to say the nose and tail of the board rise relative to the middle section of the board. In order to provide more manoeuvrability than a longboard, shortboards are available, these being thinner and narrower with a higher rocker line than longboards, typically 5.6 to 7 feet (1.7 to 2.1 metres) in length. The increased manoeuvrability comes at the expense of greater skill being required of the rider. Typical volumes for shortboards would be in the range of 22 to 28 litres for a 5'4" to 5'6" (1625mm-1676mm) board or 23 to 30 litres for a 6' to 6'2" (1828mm-1879mm) board.

I

The overall performance of a surfboard is governed by many different features of the board. For example, the turning performance of the board is affected by the shape, thickness and curvature of the rails (the sides of the board), the hull shape, the tail shape, the rocker, and by the number, size, shape, angle, toe and arrangement of the fins. The shape of the underside of the board (flat, convex or concave) affects the speed of the board and how the board feels in the water. The overall volume and the volume distribution affect the stability and speed of the board, and the length and width of the board affect its stability and manoeuvrability. Over the past 50 years there have been huge numbers of proposals for varying almost every aspect of board design but still today most beginners start on a relatively traditional style of board know as a Mini-Mal which is about 7' (2 133.6mm) long.

For reasons of safety and confidence beginners tend to start surfing in relatively shallow water and in smaller waves. It can be difficult for beginners to manoeuvre longboards to catch waves and also because it takes beginners more time to rise from a prone paddling position to a standing surfing position, often the beginner is only just in the standing position when the water becomes so shallow that the fin catches the seabed causing the rider to fall off. In addition, shortboards tend to offer little stability for beginners and intermediates due to the low board volume and narrow plan shape. Beginners and intermediates are also often practising in relatively confused white water or broken water which does not suit conventional surfboards well.

The present invention is intended to provide a board which is targeted at beginners and intermediates and is thus easy to ride, especially in smaller waves, slower white water, or breaking waves and shallow water.

A first aspect of the present invention, especially applicable to surfboards, is that the board of the invention is generally wider and thicker, and thus much higher volume, than a conventional surfboard of the same length. Preferably, for boards of length from 5'4" to 6'6" (1625.6mm-1981.2mm) the maximum width is at least 580mm (23"), more preferably at least 600mm, more preferably at least 650mm. The maximum width is reached at about 55% to 65% of the length of the board back from the front, for boards between 5'4" and 6'2" (1625.6mm-1879.6mm).

Preferably the maximum width of the board is at least 30 % of the length of the board, more preferably at least 35%, yet more preferably at least 40%.

The volume is preferably above 50 litres, more preferably above 60 litres, yet more preferably above 70 litres, for boards of 6'2" (1879.6mm) or less in length.

Example volume ranges are 50 to 75 litres for a 5'4" to 5'6" (1625.6mm-1676.4mm) board or 50 to 90 litres for a 6' to 6'2" (1828.8mm -1879.6mm) board. More preferably the volume of the boards is in the 60 to 90 litre range for a 5'4" to 6'2" (1625.6mm -1879.6mm) board. A conventional surfboard thus has from 4 to about 6 litres of volume per foot (30cm) of length whereas according to this aspect of the invention the board has upwards of approximately 8 litres per foot (3 0cm) of length for a board of 6'2" (1879.6mm) or less (though of course in no board is the volume evenly distributed along the length).

The mid section of the board in particular, being the section under the rider's front foot, broadly speaking from a point 25% to a point 50% of the length of the board back from the front, is much thicker than on a conventional board meaning that this section has a greater volume than a conventional board. The mid section preferably has a maximum thickness of at least 85mm, more preferably at least 100mm, yet more preferably 110mm or 125mm or more.

The mid section of the board preferably has a generally flat, or slightly concave underside. It preferably has a width of at least 5 80mm, more preferably at least 600mm, more preferably at least 650mm. Preferably the mid section of the board has or low or no, rocker.

The board also is wider at the tail, typically at least 25% of the length of the board, for example at least 400mm, preferably at least 450mm, more preferably over 500mm.

A second aspect of the invention is that the underside of the rear section, preferably the rear half, of the board is provided with one or more longitudinal channels of trapezoidal cross section. The underside of the board forms the roof of the channel or channels and the side walls are defined by the sloping side surfaces of longitudinally extending elongate spines depending from the underside of the board. One channel would be defined between two spines, two channels would be defined between three spines, or three channels would be defined between four spines.

The roof of the channel or channels, defined by the underside of the board, is preferably generally flat transversely of the board but rises rearwardly of the board towards the tail to form the rocker of the board. Alternatively the roof can have a series of longitudinally extending parallel shallow ridges or steps to alter the tuning of the board by changing the water flow through the channels. The depth of the channel preferably increases from zero at the rear of the mid section of the board to a maximum depth at the tail. The channel, or at least two of, the channels are wider than they are deep, for example at least twice, more preferably two-and-a-half or three times as wide as they are deep. The channel or channels are preferably substantially straight and parallel, e.g. plus/minus 10mm. Preferably they have a maximum depth which is from 25% to 75% of the maximum depth of the board, more preferably 45% to 75%, yet more preferably 50% to 65%.

The relatively low rocker, flat mid section from 25% to 50% back from the front of the board allows water to flow quickly into and through the channels.

Another aspect of the invention is that the channels, which define the longitudinally extending elongate spines, have sides whose surfaces provide lateral resistance to waterfiow and thus obviates the need for a fin or fins. Thus the board can be regarded as finless, i.e. has no conventional fin. Because of the high volume and depth of the board the spines can be, and are preferably, integrally formed with the board. The spines have their length in a longitudinal direction of the board and a depth from the underside of the board, the depth being less then the length. At least one of the spines, preferably the middle one or ones, will extend preferably from mid- length of the board to the tail of the board. The outer spines may be shorter -stopping short of the tail, e.g. by 30 to 100 mm. Alternatively or in addition they may not extend as far forwardly as the centre spine or spines, e.g. by 20 to 480 mm. The spines are preferably straight and substantially parallel. They are preferably parallel to the centre line of the board, and one may extend along the centre line of the board.

They preferably depend substantially perpendicularly, more preferably perpendicularly, from the underside of the board, but preferably have a triangular cross section being wider where they meet the underside of the board than at their free edge. Preferably their width at the base is greater than 10mm, more preferably greater than 15mm. In side view they taper gradually from rear to front. The central spine or spines are preferably at least five times as long a their maximum depth. The length of the central spine or spines is preferably from 30% to 50% of the length of the board, more preferably 40 to 50%. Preferably they do not extend into the mid section, i.e. into the front half of the board. There may be two, three or four or five spines.

The length of the spines affects the tuning of the board. Positioning the front of the outer spines further toward the back of the board will allow the water to flow across the channel or channels in the middle area of the board against the central spine in addition to flowing straight down the channel(s). This has the effect of making the board looser and easier to carve appealing to intermediates or progressive surfers. The spines may also finish before reaching the tail of the board, which again will have the effect of making the board feel looser to the intermediate surfer.

Although preferable to manufacture the spines integral with the board, especially for boards aimed at beginners (e.g. for surf schools), tt is possible to provide the spines as separate items which are mountable to the board and thus interchangeable to allow different lengths or depths allowing the board rider to change the tuning of the board as required.

The preferred triangular transverse cross section of the spines, which allows them to have a relatively thick base, at least 20mm, more preferably at least 30mm, where they join the underside of the board makes the board suitable for mass manufacture by moulding, for example rotomoulding, thus reducing the cost, allows for the use of recyclable plastics and the option of manufacture close to the local market in which the invention may be sold. In addition the ends (rear edge) of the spines may be square, rounded, or more preferably chamfered (when viewed from below) in order to aid release of the flowing water from the tail end of the board Preferably the profile of the spines is such that their free edge (the bottom edge if the board is the right way up) is about level with, or more preferably no more than slightly proud of, the plane of the mid section of the underside of the board.

Consequently the free edge of the spines and underside of the mid section conform substantially to a flat surface. However the spines can be made slightly deeper so as to extend beyond that plane. The central spines may extend slightly deeper than the outer spines or vice versa. This shape of spine -elongate and generally in a plane with the main part of the underside of the board means that the board is usable in very shallow water without catching on the seabed. It also allows the board to be placed flat on the beach where riders can easily practise rising from the prone to the standing position. It also makes the board safer as there is no long sharp fin to injure the rider or other water users.

This aspect of the invention, the provision of channels and spines, is applicable not only to surfboards but also to stand-up paddleboards, windsurf boards and kitesurf boards.

In order to allow the board to turn and grip the face of the wave, the thickness of the rails at the rear section of the board, i.e. the laterally outer part of the rear section of the board, outside the outer spines, preferably the rear third or quarter, is less than the thickness of the mid section of the board. Thus the volume of the rails drops from the mid to the rear section of the board. From the middle of the board to the tail the rate of volume decrease of the rail is much higher than is conventional.

Preferably the thickness of the rails at the rear, e.g. the rear quarter of the board, measured 2" (50.8mm) in from the outer edge is less than half the thickness of the rails at the mid section, preferably less than 40% of the maximum thickness of the rails.

The maximum thickness of the section of the board outside of the outer spines in the rear of the board, e.g. the rear 15% of the board, is preferably less than the thickness of the mid section, preferably less than 50mm, in the the rear third of the board the thickness of this section is preferably less than 90mm.

More preferably the thickness of the rails (measured 25mm in from the side of the board) in the rear 15%, of the length of the board is less than 45mm. Preferably the thickness of the rails (measured 25mm in from the side of the board) in the rear 25%, of the length of the board is less than 50mm.

Preferably the thickness of the rails in the rear third of the board measured 50mm in from the outer edge of the board is no more than 80 mm, more preferably no more than 65mm.

In another aspect of the invention the centre underside of the nose of the board can be provided with a longitudinally-extending ridge, preferably of V-cross-section, to assist directional stability.

The short length of the board makes it particularly manoeuvrable, allowing the rider to spin the board quickly to catch a wave improving its usability in areas where waves are generally small. In fact this means that although the board is targeted at beginners or intermediates, expert riders can enjoy surfing when surf conditions are too poor for more advanced boards.

The increased volume of the board also permits the rider to sit higher In the water and therefore facilitates a better view of approaching waves and increases the liklihood of a beginner catching a wave.

Another aspect of the invention is that the greater volume of the board allows for the creation of a concave dished or flattened top surface, for example by 10 to 30 mm in depth which makes it more comfortable for beginners as well as lowering the centre of gravity of the rider, aiding stability. The dishing effect also then allows for the creation of integral kicktail for more progressive surfers.

Due to the higher volume and greater widths than normal boards, the board may have an additional small indent approximately 20mm wide by 70mm long by 20mm deep on the top side of the board positioned a point close to the centre, where the board's balance point can be achieved. This indent provides a handhold to allow easier carrying of the board.

The above aspects of the invention may be used separately or together in any combination, and may be combined with various of the preferred features to provide an improved board-type watercraft.

The invention will be further described by way of examples with reference to the accompanying drawings in which:-Figure 1 illustrates a first embodiment of the invention, with the board inverted (topside down) with three longitudinal spines defining two channels; Figure 2 is a side view of the board of Figure 1; Figure 3 is a view of the topside of the board of Figure 1; Figures 4a to 4d are respectively rear, front, top and bottom elevations, to scale, of the board of Figure 1; Figures 5a and Sb are rear three-quarter perspective views from above and below respectively of the board of Figure 1; Figures 6a to 61 are transverse cross-sections, to scale, of the board of Figure 1 at the positions indicated in Figure 4d; Figure 7 perspective view from rear and below of a second embodiment of the invention with four longitudinally extending spines; Figure 8 is a view from below of the board of the second embodiment of the invention; Figures 9a to 9m are transverse cross-sections, to scale, of the second embodiment of the invention at the positions indicated in Figure 8; Figure 10 is a side elevation, to scale, of the second embodiment of the invention; Figure 11 is a schematic perspective view of a third embodiment of the invention in which the outer pair of three spines are shorter than the central spine; Figure 12 is a schematic perspective view of a fourth embodiment of the invention showing a board with three spines of greater depth than Figure 1; and Figure 13 is a schematic perspective view of a fifth embodiment of the invention in which the outer pair of three spines are shorter than the central spine.

Figure 1 illustrates a first embodiment of the invention. A surfboard can functionally be divided into three sections front to rear, these being a front section 1, a mid section 3 and a rear section 5. The front section 1 extends from the nose 7 to the front of the mid section 3. The rear section 5 extends from the rear of the mid section 3 to the tail 9 of the board. The mid section 3 generally corresponds to the area where the rider places the front foot and the rear section 5 corresponds to the area where the rider places the rear foot though certain tricks can involve different foot positions.

Broadly speaking the rear section is the rear half of the board. The front and mid sections share the front half of the board, and the case of this invention the front section 1 is about the front 20% of the board, the mid section 3 extending from there back to the half way point.

The mid section 3 of the board is generally flat (i.e. has little rocker), thick and wide. Boards can be provided in different lengths for different size riders so typical members of a family of such boards might be:-

Table 1

Length Maximum Width 1828.8mm-1879.6mm (6' to 6'2") 609.6mm-723.9mm (24"-28.5") 1625.6mm-i 676.4mm (5 4"-5 6") 584.2mm-685.8mm (23"-27") 1524mm (5') 584.2mm-635mm (23"-25") The board also has its maximum thickness in the mid section 3, this being typically 3.5 inches (88.9mm)or more. The rails 11 of the board in the mid section are rounded at their bottom corner, and relatively thick as seen in the cross-sections of Figures 6f, 6g, 6h.

As is well known most if not all surfboards are provided with rocker, in that the nose and tail of the board rise compared to the mid section. With the present invention the mid section has relatively small, or no rocker, but a relatively conventional amount of rocker in the front section 1 where the underside of the board rises towards the nose 7. In the rear section 5 of the board two channels 19 are formed by curving the underside 17 of the board upwards in a conventional rocker profile leaving three spines, 13, 13 and 15 which form the side walls of the channels.

The spines 13 and 15 thus defined are elongate longitudinally extending spines of triangular cross section formed integrally with the board. The flat sections 17 of the underside of the board between the spines define together with the spines the two channels 19 which rise towards the tail of the board to provide the rocker in the rear section of the board. Thus the channels 19 have a depth which increases from zero at the rear of the mid section 3 (about half way up the board) to its maximum at the tail of the board. In the example illustrated in Figure 1 the maximum depth at the tail of the board is about 80mm, though it may range from 50 to 90 mm. The width of the channels 19 at their mid-depth is about 200-215mm (about 8 to 8.5 inches).

The spines 13, 15 have a triangular cross section so as to provide a strong junction at their root with the main part of the board. As seen more clearly in the rear view of Figure 4a the central spine 15 is symmetrical having a base of about 30mm width whereas the two side spines 13 are asymmetric in cross section. The inclination of the outside of each of the spines 13 is steeper than the inclination of the inside, this being achieved by the free (bottom) edge 13a of the spines being displaced laterally outwardly of the centreline of the spine base by about 2 to 3mm. The thickness of the base of the spines 13 is about 25mm.

The free edges 1 3a, 1 5a of the spines in this embodiment conform substantially to the plane of the mid section of the board (marked P in Figure 2), in fact the spines project slightly beyond the plane P by no more than 10-15mm, more preferably no more than 15% of their depth. Thus in profile the mid and rear sections of the board conform substantially to a flat surface. This makes the board easy to use in shallow water and allow it to lay flat on a beach as there is no significant projection (no more than 15% of the depth of the spine) beyond the plane P. This in turn means that the depth of the spines 13 and 15 decreases towards the front, reaching zero at the start of the mid section 3. The central spine 15 is slightly deeper than the outside spines 13. It extends 10-15mm below the plane P whereas the outer spines 13 extend by only 5-10mm below the plane P In an alternative embodiment illustrated in Figure 12, however, the spines can be made deeper by curving the free edge 13b, 15b so that it projects further beyond the plane P, though not to the extent that they would catch in the seabed like a conventional fin.

In general beginners to surfing occupy themselves with practising rising from a prone to a standing position to catch a wave, and then generally surf straight down the front of the wave. As confidence and skill increases, however, the rider wants to be able to turn the board to travel across the face of the wave. This is achieved by angling the board so that it carves a turn in the water and the spines 13, 15 and rails 21 in the rear section of the board are critical in this turning process. In order to provide the boards of the present invention with a good turning ability the laterally outer areas 23 of the rear section 5 outside the outer spines 13 have their volume significantly and progressively reduced towards the rear of the board. This is achieved by the flat underside of the board in these areas following the same or similar rocker line as the roof 17 of the channels 19. Furthermore, the rails 21 themselves are provided with a sharper (bottom) corner than the rails 11 in the mid section. This tighter radiusing of the rails 21 compared with the rails 11 can be seen clearly by comparing the cross-section of Figure 6b (at 250mm from the tail) with that of Figures of, 6g and 6h (at 850mm, 1000mm and 11 50mm from the tail).

The reduced volume of the rear outer areas 23 means that when the board is travelling across the wave the rear rails 21 and outer areas 23 are not pushed out of the wave by their own buoyancy. If the outer areas 23 were as thick or thicker than the mid section the board could not be surfed across a wave because their buoyancy would push the board away from the water and would prevent them gripping into the wave.

Preferred ranges for the rail thicknesses in mm are given in Table 2 below for a board of length 1625.6mm-1676.4mm (5'4"-5'6"). These are measured at the indicated approximate distances (percentages of the length also given) from the tail of the board 1" (25.4mm) and 2" (50. 8mm) in from the outer edge. It should be noted that the ranges at each point are independent of the ranges at other points and so usable independently within the constraints of the desired overall board and rail shape.

S

Table 2

Distance 100 250 400 550 700 850 1000 1150 1300 1400 1500 1600 From (6%) (15%) (24%) (33%) (42%) (50%) (60%) (70%) (80%) (85%) (90%) (6%) Tail mm (%) 25.4mm 31.75-38.1-34.925-44.45-50.8-57.15-57.15-50.8-47.625-44.45-34.925-25.4-in 44.45 41.275 44.45 47.625 57.15 60.325 63.5 57.15 57.15 50.8 44.45 31.75 from edge (mm) 50.8mm 31.75-53.975-47.625-57.15-66.675-69.85-73.025-63.5-60325-57.15-44.45-31. 75-in 47.625 57.15 53.975 60325 69.85 76.2 69.85 69.85 69.85 63.5 57.15 44.45 from edge (mm) As can be seen in Figure 1 the outer spines 13 meet the tail of the board at the same point as the rails 21, though they can finish short of the tail as explained in more detail below.

The front section 1 of the boards of the invention have a relatively conventional rocker of about 5 inches or more (127mm) formed by the underside of the board rising to the nose 7. The underside of the front section in this embodiment is also provided with a central ridge 23 of triangular cross section. The ridge 23 is from 30cm to 45cm long, about 10 to 15mm deep and about 50mm wide at the base, though as can be seen from its cross-section in Figures 9h to 91 it merges smoothly with the underside of the board so its width is not well-defined. The leading ridge 23 provides the board with good longitudinal stability, especially when paddling or on take-off.

The topside of the board as illustrated in Figure 3 is relatively conventional, but the additional depth and volume of the board allow it to be dished by up to 25mm to provide a defined area 31 between slightly raised sides 33 where the rider can stand, this area also being more ergonomic for paddling prone. It also helps provide stability by lowering the rider's centre of gravity. It also enables the board to be provided with a raised kicker 30 on the tail (also visible in Figure 2) which gives the rider's rear foot better control if executing more progressive manoeuvres. A leash point 32 can be provided at the rear of the board.

Figures 6a to 61 are transverse cross-sections of the board of Figure 1 (which is a 5'4" to 5'6" (1625.6-1676.4mm) board, taken at the positions marked in Figure 4.

They are to scale and thus proportions are correct, and proportions and scale dimensions measured from them are correct. The cross-section positions measured from the tail, together the overall width and depth at each position are indicated in

Table 3 below.

Table 3

Figure Position Overall Overall depth (mm) (z-dimension in mm measured width (including spine or ______ from tail (mm) ridge) 6a 100 465.4 136.4 6b 250 555.8 129.0 6c 400 614.2 124.0 6d 550 647.3 121.0 6e 700 657.1 120.1 6f 850 651.6 118.5 6g 1000 632.0 117.3 6h 1150 596.8 113.1 6i 1300 534.5 108.9 6j 1400 469.8 100.7 6k 1500 377.0 85.4 61 1600 231.1 58.1 The overall depth d of the board of this embodiment is 156.1mm (see Figure 4b) and the overall length 168 1.1mm (5'6") (see Figure 4c).

The embodiment above has been illustrated with three longitudinally extending spines 13, 13, 15 in the rear section 5. However the number of spines can be varied. A single central spine 15 is possible, though this gives a board which is rather loose in feel. Two longitudinally extending spines tighten the feel of the board and work reasonably if turning ability is not critical. The provision of the central spine 15, giving three spines in total, improves the turning ability of the board.

Figure 7 illustrates a board with four longitudinally extending spines 51, 52, this giving a board which is very stable in a straight line, though not as manoeuvrable as the three spine board. As illustrated the outside spines 51 extend further towards the front of the board by about 280mm than the inner spines 52. Also as illustrated in figure 9a to 9g the inner spines 52 are shallower than the the outer spines 51 being about 50% of the depth of the outer spines. The outer spines 51 are from 60 to 65mm deep at their maximum and the inner spines about 30mm deep at their maximum. All four spines are about 30mm wide at the join with the underside of the board.

The central nose ridge 23 in this embodiment extends much further back than in the first embodiment-extending about 35% of the way back from the nose, or about 650 mm in the illustrated board which has an overall length of 1817.4 mm (6 feet). The nose ridge is also deeper -about 20 to 25mm deep. The overall depth d of the board of this embodiment as illustrated in Figure 10 is 150.2mm (6 inches).

Figures 9a to 9m are transverse cross-sections of the board of Figure 7 taken at the positions marked in Figure 8. They are to scale and thus proportions are correct, and proportions and scale dimensions measured from them are correct. The cross-section positions measured from the tail, together the overall width and depth at each position are indicated in Table 4 below.

Table 4

Figure Position Overall Overall depth (mm) (z-dimension in mm measured width (including spine or ______ from tail (mm) ridge) 9a 100 530.1 123.9 9b 250 626.7 120.1 9c 400 684.3 118.2 9d 550 716.6 118.6 9e 700 729.9 119.7 9f 850 727.6 118.3 9g 1000 710.5 116.4 9h 1150 680.7 116.2 9i 1300 638.5 116.6 9j 1450 572.5 111.0 9k 1550 503.4 103.2 91 1650 407.6 92.3 9m 1750 239.1 66.9 As illustrated in Figures 1 to 12 these embodiments are provided with a conventional V-shaped tail, though any of the multiplicity of known tail and end rail shapes e.g. including, but not limited to, squashtail, squaretail, pintail, thumbtail, swallowtail, battail, wingtail, stinger (as shown in Figure 13), etc. The Figure 13 embodiment also illustrates a board with no nose ridge.

The above Figures illustrate the longitudinal spines as extending fully to the tail 9 of the board. It is possible, however, for the spines, especially the outer spines 13, 51, to terminate short of the tail of the board, as shown by spines 131 in Figure 13, andlor to start after the start of the central spine(s) for example as illustrated by spines in Figure 11. The starting and ending position of the outer spines can also be used to alter the performance of the board as mentioned above.

The board is designed to be mass manufacturable by a molding technique such as rotomoulding out of polyethylene. However the board can, of course, be made by the traditional technique of shaping a blank of polyurethane foam (which usually incorporates one or more longitudinal wooden stringers) and coating it with glass reinforced resin, or with a similar technique but using the more modem greener plant based foams and natural glassing agents.

The embodiments above also have an additional small indent 20 approximately 20mm wide by 70mm long by 20mm deep on the top side of the board positioned a point close to the centre, where the board's balance point can be achieved. This indent provides a handhold to allow easier carrying of the board.

The above embodiments show surfboards, but the various aspects of the invention are applicable individually and in any combination to other board-type watercrafi such as stand-up paddleboards, windsurfers and kitesurf boards. A kitesurf board according to the invention would be of the order of 120-150cm long (4'-5'), whereas a stand-up paddleboard would be of the order of 210 to 335cm (7'-ll') long, and a windsurf board up to 230 to 280cm long, but all with widths and/or volumes in similar proportions to the embodiments above.

Claims

CLAIMSI. A board-type watercrafi having a front section, mid section and rear section, the front section extending from the nose to the mid section and the rear section extending from the mid section to the tail, the edges of the board defining rails, the mid section having a generally flat underface, a thickness substantially equal to 80mm or more, a width at its maximum substantially equal to 580mm or more; the rear section having protruding from its underside a plurality of elongate spines having their length in a longitudinal direction of the board and a depth from the underside, the depth being less then the length; the spines defining with the underside of the board one or more channels whose depth increases from front to rear of the board, the channels having a width greater than their depth; the rail thickness decreasing from the mid to the rear section of the board.
2. A board-type watercraft according to claim I wherein the thickness of the rear section of the board laterally outside the outer spines is less than the thickness of the mid section.
3. A board-type watercraft according to claim I wherein the maximum thickness of the rear section of the board laterally outside the outer spines is less than the maximum thickness of the mid section.
4. A board-type watercraft according to claim 1, 2 or 3 wherein the mid section of the board has substantially no or low rocker.
5. A board-type watercraft according to claim 1, 2, 3 or 4 wherein the mid section of the board is between a point 25% and a point 50% of the length of the board measured from front to rear.
6. A board-type watercraft according to any one of the preceding claims wherein thickness of the rear rails measured 25mm in from the outer edge of the board is no more than 50mm.
7. A board-type watercraft according to any one of the preceding claims wherein the thickness of the rails in the rear third of the board measured 50mm in from the outer edge of the board is no more than 80mm.
8. A board-type watercratt according to any one of the preceding claims wherein the depth of the spines tapers towards the front of the rear section.
9. A board-type watercraft according to any one of the preceding claims wherein the length of the middle spine or spines longitudinally of the board is at least five times their maximum depth.
10. A board-type watercraft according to any one of the preceding claims wherein the length of the middle spine or spines longitudinally of the board is at least 30% of the length of the board.
11. A board-type watercrafl according to any one of the preceding claims wherein the spines have a triangular cross-section transversely of the board with a root section adjoining the underside of the board and being thicker than the free edge of the spines.
12. A board-type watercraft according to claim 14 wherein the root section is at least 20 mm wide.
13. A board-type watercrafi according to any one of the preceding claims wherein the free edge of the spines is substantially continuous with the underside of the mid section.
14. A board-type watercrafi according to claim 13 wherein the free edge of the spines and the underside of the mid section of the board substantially conform to a flat plane.
15. A board-type watercraft according to claim 14 wherein the free edge of the spines extends by no more than 40% of the maximum spine depth below the underside of the mid section of the board.
16. A board-type watercrafi according to claim 14 or 15 wherein the free edge of the spines does not protrude substantially below the plane of underside of the mid section of the board.
17. A board-type watercraft according to any one of the preceding claims wherein the underside of the board in the channels is substantially flat.
18. A board-type watercrafl according to any one of the preceding claims wherein the channels have a width at least twice their maximum depth.
19. A board-type watercraft according to any one of the preceding claims wherein the channels have a length at least twice their width.
20. A board-type watercraft according to any one of the preceding claims wherein the channels are substantially straight.
21. A board-type watercrafl according to any one of the preceding claims wherein the underside of the nose of the board is provided with a ridge extending longitudinally of the board.
22. A board-type watercraft according to claim 21 wherein the ridge has a triangular transverse cross section.
23. A board-type watercrafl according to claim 21 or 22 wherein the ridge is on the centreline of the board.
24. A kitesurf board having a front section, mid section and rear section, the front section extending from the nose to the mid section and the rear section extending from the mid section to the tail, the edges of the board defining rails, the board being no more than 150cm long, the mid section having a generally flat underface, a thickness substantially equal to 60mm or more, a width at its maximum substantially equal to 500mm or more; the rear section having protruding from its underside a plurality of elongate spines having their length in a longitudinal direction of the board and a depth from the underside, the depth being less then the length; the spines defining with the underside of the board one or more channels whose depth increases from front to rear of the board, the channels having a width greater than their depth; the rail thickness decreasing from the mid to the rear section of the board.Amendment to the claims have been filed as followsCLAIMS1. A board-type watercraft having a front section, mid section and rear section, the front section extending from the nose to the mid section and the rear section extending from the mid section to the tail, the edges of the board defining rails, the mid section having a generally flat underface, a thickness substantially equal to 80mm or more, a width at its maximum substantially equal to 580mm or more; the rear section having protruding from its underside a plurality of elongate spines having their length in a longitudinal direction of the board and a depth from the underside, the depth being less then the length; the spines defining with the underside of the board one or more channels whose depth increases from front to rear of the board, the channels having a width greater than their depth; the rail thickness decreasing from the mid to the rear section of the board.2. A board-type watereraft according to claim 1 wherein the thickness of the rear section of the board laterally outside the outermost of the elongate spines is less than the thickness of the mid section.3. A board-type watercraft according to claim I wherein the maximum thickness of the rear section of the board laterally outside the outermost of the elongate spines is less than the maximum thickness of the mid section.4. A board-type watercraft according to claim 1, 2 or 3 wherein the mid section of the board has substantially no or low rocker.* S...* ** * 5. A board-type watercraft according to claim 1, 2, 3 or 4 wherein the mid section of the board is between a point 25% and a point 50% of the length of the :.: . board measured from front to rear. * S. * I S * S * 206. A board-type watercraft according to any one of the preceding claims wherein the thickness of the rails in the rear section of the board, measured 25mm in from the outer edge of the board is no more than 50mm.7. A board-type watercraft according to any one of the preceding claims wherein the thickness of the rails in the rear third of the board measured 50mm in from the outer edge of the board is no more than 80mm.8. A board-type watercraft according to any one of the preceding claims wherein the depth of the spines tapers towards the front of the rear section.9. A board-type watercraft according to any one of the preceding claims wherein the length of the middle one or ones of the elongate spines longitudinally of the board is at least five trifles their maximum depth.10. A board-type watercrafi according to any one of the preceding claims wherein the length of the middle one or ones of the elongate spines longitudinally of the board is at least 30% of the length of the board.11. A board-type watercrafi according to any one of the preceding claims wherein the spines have a triangular cross-section transversely of the board with a root section adjoining the underside of the board and being thicker than the free edge of the spines.12. A board-type watercraft according to claim 14 wherein the root section is at least 20 mm wide.13. A board-type watercraft according to any one of the preceding claims wherein * : *.: the free edge of the spines is substantially continuous with the underside of the mid section. * ** ** S *** S14. A board-type watercraft according to claim 13 wherein the free edge of the spines and the underside of the mid section of the board substantially conform to a : * flat plane. * 2115. A board-type watercraft according to claim 14 wherein the free edge of the spines extends by no more than 40% of the maximum spine depth below the underside of the mid section of the board.16. A board-type watercraft according to claim 14 or 15 wherein the free edge of the spines does not protrude substantially below the plane of the underside of the mid section of the board.17. A board-type watercraft according to any one of the preceding claims wherein the underside of the board in the channels is substantially flat.18. A board-type watercrafl according to any one of the preceding claims wherein the channels have a width at least twice their maximum depth.19. A board-type watercraft according to any one of the preceding claims wherein the channels have a length at least twice their width.20. A board-type watercraft according to any one of the preceding claims wherein the channels are substantially straight.21. A board-type watercraft according to any one of the preceding claims wherein the underside of the nose of the board is provided with a ridge extending longitudinally of the board.22. A board-type watercraft according to claim 21 wherein the ridge has a triangular transverse cross section.* 23. A board-type watereraft according to claim 21 or 22 wherein the ridge is on the centreline of the board. * S. * * * S.. *24. A kitesurf board having a front section, mid section and rear section, the front section extending from the nose to the mid section and the rear section extending from * the mid section to the tail, the edges of the board defining rails, the board being no more than 150cm long, * 22 the mid section having a generally flat underface, a thickness substantially equal to 60mm or more, a width at its maximum substantially equal to 500mm or more; the rear section having protruding from its underside a plurality of elongate spines having their length in a longitudinal direction of the board and a depth from the underside, the depth being less then the length; the spines defining with the underside of the board one or more channels whose depth increases from front to rear of the board, the channels having a width greater than their depth; the rail thickness decreasing from the mid to the rear section of the board. * *I****** * S * I. * S * I*S S S. ** * U *S I