Board-like sportscraft

Abstract

A board-like sportscraft comprises a core and a metallic skin covering at least a portion of said core.

Description

[0001] This invention relates to a board-like sportscraft. In particular, the invention relates to sportscraft for use on water such as surf boards, sail boards, boogie boards, knee boards, body boards and surf skis but may also relate to other board-like craft such as snow boards.

[0002] Conventional board-like sportscraft such as surf boards comprise a core of a foamed plastics material encased in a fibreglass skin. The core of foamed plastics material provides strength and buoyancy for the craft while the fibreglass skin provides a smooth, low friction surface over which water moves easily and rapidly. The strength of the board may be enhanced by provision of a stringer, usually made of a hardwood material or of plywood, which is attached to (or integrated into) the core before the core and stringer together are coated with fibreglass.

[0003] The hard outer fibreglass skin can often be subject to damage from impact creating “dings” or “bruises” in the board. When this happens, the fibreglass starts to deteriorate which may cause delamination and weakness in the board. Indeed, the construction of surf boards has become so lightweight in modern times that it is not uncommon for lightweight boards to break completely. Moreover, the low friction fibreglass surface, while serving the purpose of allowing water to move rapidly against the underside of the board has the disadvantage that it is difficult for the rider to keep his or her feet in secure contact with the board, and effective contact with the board is a prerequisite of many manoeuvres which users of such boards may wish to perform. In order to overcome this disadvantage wax is applied to the top surface, or deck, of the board to provide grip for the feet of the user, and this is a time consuming and tedious operation. still further, conventionsl fibreglass boards suffer from a structural weakness which may cause portions of the board to sag or hog.

[0004] According to a first aspect of the present invention, there is provided a board-like sportscraft comprising a core and a metallic skin covering at least a portion of said core.

[0005] Preferably, said metallic skin covers at least 75% of the surface of said core.

[0006] Preferably, said metallic skin covers substantially all of said core.

[0007] Preferably, said core includes two side rail portions and the metallic skin covers at least 75% of each of said side rail portions.

[0008] Preferably, said core includes a deck portion, and a bottom surface portion and the mean thickness of said metallic skin is greater on said side rail portions than the mean thickness of the metallic skin on said deck portion and bottom surface portion.

[0009] Preferably, there is provided a surface portion of the core which is not covered by said metallic skin, in order to mitigate or avoid damage to said board-like sportscraft due to differential thermal expansion between said metallic skin and said core.

[0010] Preferably, the core includes surface features which are substantially reproduced in the metallic skin, and the surface features are adapted to provide a user with enhanced grip or control of the craft.

[0011] Preferably, said board-like sportscraft is a surf board, and said features are provided on or adjacent the deck and/or rails of the surf board.

[0012] Preferably, at least some of the outer surface of the metallic skin is highly reflective.

[0013] Preferably, at least a portion of the outer surface of the metallic skin is non-reflective and where said non-reflective portion is towards the front of the board-like sportscraft and on an upper surface thereof so as to avoid direct reflection of sunlight onto the face of a user.

[0014] Preferably, there are provided one or more connecting members formed from a material having greater rigidity than the core, and wherein said connecting members pass through the core in order to enhance the rigidity of the connection between a bottom surface of said sportscraft and an upper surface of said sportscraft.

[0015] Preferably, said connecting members are rods, pillars, posts, wires or the like.

[0016] Enhancing the rigidity of the connection between upper and lower surfaces is desirable in order to improve the feel of the sportscraft.

[0017] Preferably, at least a portion of the outer surface of the metallic skin provides a smooth low friction surface. In the case of, for example, a surf board, a bottom portion of the board is preferably provided with such a surface.

[0018] Preferably, at least a portion of the outer surface of the metallic skin provides a high friction surface to facilitate grip by a user. in the case of a surf board, a portion of the board deck is preferably provided with such a surface.

[0019] Preferably, the metallic skin is composed mainly from a metal chosen from the group consisting of: aluminium; stainless steel; aluminium alloys.

[0020] Preferably, there is provided an inner coating layer, between the core and the metallic skin, and said inner layer is composed of different material to said metallic skin.

[0021] Preferably, said inner layer is provided in order to facilitate or enhance adhesion of said metallic skin to said core.

[0022] Preferably, said inner layer includes a substantial zinc component.

[0023] Preferably, said inner layer is composed mainly or substantially entirely of zinc.

[0024] Preferably, at least a portion of the outermost surface of the board-like sportscraft is formed of a material having a low thermal conductivity. This provides a portion of the board-like sportscraft by which the board-like sportscraft can be carried even when very hot.

[0025] Said core may be provided with a number of longitudinal grooves therein, and said longitudinal grooves may be filled with a metallic substance in order to provide the board-like sportscraft with enhanced longitudinal strength.

[0026] According to a second aspect of the present invention, there is provided a method of manufacturing a board-like sportscraft comprising the steps of:

[0027] preparing at least a portion of a shaped core for a board-like sportscraft for coating with a metallic skin;

[0028] coating at least a portion of said core with a metallic skin.

[0029] Preferably, said method includes the step of coating said at least a portion of said core with an intermediate coating layer, and said step of coating at least a portion of said core with a metallic skin comprises applying said metallic skin onto at least a portion of said intermediate coating layer.

[0030] Preferably, said intermediate coating layer is composed entirely or mainly of zinc.

[0031] Preferably, said metallic skin is formed from a substance composed entirely or mainly of a metal chosen from the group including: aluminium; aluminium alloy; stainless steel.

[0032] Preferably, said core is formed from a foam material.

[0033] Preferably, said step of coating with a metallic skin includes spraying a metallic substance to form the metallic skin.

[0034] Preferably, the spraying of the metallic substance is performed by a thermal metal spray process.

[0035] Embodiments of the present invention will now be described, by way of example only, with reference to the accompanying drawings in which:

[0036] FIG. 1 is a schematic vertical cross-section taken across the width of an embodiment of a board-like sportscraft in accordance with the present invention in the form of a surf board;

[0037] FIG. 2 shows schematically a cross-section of the rail section of the embodiment of FIG. 1 in greater detail;

[0038] FIG. 3 shows a block diagram illustrating a preferred method of manufacturing an embodiment of a board-like sportscraft in accordance with the present invention in the form of a surf board;

[0039] FIG. 4 is a plan view of an embodiment of a board-like sportscraft in accordance with the present invention in the form of a surf board, showing schematically areas of the surf board having different surface finishes;

[0040] FIG. 5 is a plan view of a variation of the embodiment of FIG. 1;

[0041] FIG. 6a is a cross-sectional view on VIa-VIa of FIG. 5;

[0042] FIG. 6b is a cross-sectional view on VIb-VIb of FIG. 5; and

[0043] FIGS. 7a to 7d are partial cross-sectional views illustrating the manufacture of the embodiment of FIGS. 5 and 6.

[0044] With reference to FIGS. 1 and 2, an embodiment of a board-like sportscraft in accordance with the present invention, in the form of a surf board generally designated 1, comprises a foam core 10 of a foamed plastics material having a stringer 15 provided therein in order to provide strength thereto. The core 10 and stringer 15 may be of conventional type and shaped appropriately for the desired form of the finished board. The core and stringer together constitute a surf board blank The blank is covered in its entirety by a metallic inner layer 20 which is preferably completely or mainly composed of a first metal, preferably zinc. Along the edges or rails of the blank, a rail coating layer 30 of a second metal is provided. In the preferred embodiment, the second metal is aluminium. A metallic skin in the form of an outer metallic layer 40, preferably composed of aluminium, is provided around the entire board, covering the rail coating layer 30 provided at the rails and coating the zinc inner layer 20 provided over the rest of the board.

[0045] A board having the above described construction may be of a similar weight to a traditional fibreglass covered board but has a number of advantages thereover. The aluminium is considerably more aesthetically pleasing than fibreglass and can be buffed to a highly reflective, almost mirror-like shine making a very attractive and distinctive surf board. The aluminium rail coating 30 and outer metallic layer 40 of the board provide considerable structural strength and provide a board which is resistant to dings. In the event that damage does occur, the aluminium does not noticeably deteriorate when exposed to seawater as does fibreglass.

[0046] The application of aluminium is also considerably quicker and more easily performed than the application of fibreglass to a surf board blank and the provision of the rail coating layer 30 in addition to the outer metallic layer 40 provides a double layer of aluminium along the rails of the board which provides additional strength to these structurally important and vulnerable areas. Although schematically shown as two separate layers in FIGS. 1 and 2, the combination of rail coating layer 30 and outer metallic layer 40 along the rails may equally be regarded as a single layer of increased thickness. In FIGS. 1 and 2, the inner layer 20, rail coating layer 30 and outer metallic layer are for clarity, shown to be quite thick compared to the thickness of the core. It is important to realise that these drawings are not to scale, since in a preferred embodiment the total thickness of the metallic layers is less than 1 mm and the thickness of the core is about 60 or 70 mm, and the thickness of the metallic layers have been exaggerated only for illustrative purposes.

[0047] With reference to FIG. 3, a method of manufacturing a preferred embodiment of a board-like sportscraft in accordance with the present invention, in the form of a surf board, will hereafter be described.

[0048] A first step in the process, designated 310 in FIG. 3, is to begin with a surf board blank shaped appropriately for the desired finished board. The next step, designated 320 in FIG. 3, is to treat the surface of the shaped blank to enhance the adhesion of the first coating (e.g. the zinc inner layer 20 of FIGS. 1 and 2). Preferred methods of treatment of the surface are to roughen the surface using a grinding or scouring process or to cut or etch an appropriate pattern of grooves into the surface of the blank. A cross-hatched pattern of grooves is appropriate. A preferred depth for the grooves or the like is about 0.3 to 0.8 mm (0.001 to 0.003 inches).

[0049] A third step, designated 330 in FIG. 3, comprises coating the prepared blank with zinc. The coating with zinc is considered desirable in order to enhance adhesion of a metallic skin (e.g. the metallic outer layer of FIGS. 1 and 2) to the blank.

[0050] Coating of the blank with zinc may be performed by various means but a preferred method is to use a combustion wire thermal spray process (also known as flame spraying, metallising or metal spray process). This is a known process per se and will not be described in detail herein. However, use of an oxyacetylene flame to melt a zinc wire, which is then atomised using compressed air at approximately 80 psi to form a fine zinc spray has been found to be effective. It has also been found effective to spray the zinc (from a Schoop gun or other combustion wire thermal spray gun) onto the blank from a distance of about 0.12 m to 0.18 m (about 5 to 7 inches). Although the metal may be heated to over 2000 degrees centigrade during the spraying process, it has been found to be quite possible to apply a zinc coating to an unprotected blank in this way without noticeably heat-damaging the blank. zinc wire especially suited for use as a primer or undercoat for aluminium spraying is commercially available. A combustion powder thermal spray process (also known as powder flame spraying or low velocity oxygen fuel process) or arc wire thermal spray process are also considered appropriate and other thermal spray processes such as plasma thermal spray processing may also be applicable, but are not generally as cost effective as combustion wire thermal spray processing. Other forms of metal spraying could also be appropriate.

[0051] A coating of zinc approximately 0.05 to 0.1 mm (0.002 to 0.004 inches) thick is preferred. Since the zinc coating is provided in order to assist adhesion of the metallic outer layer to the surf board blank, it is desirable in this embodiment that the entire surface of the blank is provided with the zinc coating. As the surf board blank is relatively light in weight, and the air pressures used in spraying may be significant, it is desired to have the board clamped in a jig or stand during spraying. stands for holding work pieces for spraying are known, and will not be described in detail herein.

[0052] The next step, designated 340 in FIG. 3, is to prepare the zinc for coating with aluminium. This preparation consists of removing any unwanted flaws or irregularities in the zinc coating, bringing the zinc coating to the desired degree of smoothness, and performing any cleaning or keying necessary to achieve the desired degree of adhesion of the aluminium layer.

[0053] The next step, designated 350 in FIG. 3, is to coat the edges or rails of the board with aluminium to a depth of approximately 0.3 mm. It is envisaged that this coating could be 0.1 to 0.5 mm thick depending on the desired weight and strength of the finished board and other factors which contribute to these variables. The coating applied to the rails corresponds to the rail coating layer 30 of FIGS. 1 and 2. The rail coating layer is preferably applied by thermal spraying in a similar manner as is discussed above in relation to the zinc inner layer. The preferred method of spraying a board rail is first to move the spray gun along the rail (that is, generally in the longitudinal direction of the board with the spray gun nozzle generally in the same plane as the board) one or more times, and then to move the gun so as to spray the board in the vicinity of the rail from the board bottom direction and from the board deck direction. This provides good coverage along the most extreme edge portions of the board (the actual rail edges) and also provides a rail coating layer which extends a small distance onto the bottom and deck of the board, so as to “wrap around” the rails.

[0054] The next step, which is the final constructural step in this embodiment and is designated 360 in FIG. 3, is to coat the entire board surface (including the already-coated rails) with aluminium to a thickness of 0.1 to 0.5 mm. This provides the metallic skin (that is, the outer metallic layer 40 in FIGS. 1 and 2). In this embodiment, the outer metallic layer encapsulates the entire board adding structural strength, protecting the blank and providing a surface which is aesthetically highly pleasing.

[0055] The outer metallic layer may be applied in a similar manner as is discussed above in relation to the zinc coating, that is by a thermal spray process or the like. Of courses regulation of the thickness of the outer metallic layer is important, since irregularities may be aesthetically undesirable, and if considerable, could also affect the weight distribution, balance and manoeuvrability of the board. However, if desired, the coating could be non-uniform, in order to provide, for example, a thicker layer at vulnerable areas of the board, such as where a user's heels would impact the deck as the user makes the transition from a prone to a standing position.

[0056] The aluminium coating then undergoes the step of polishing, designated 370 in FIG. 3, (which may be performed by using successively finer abrasive materials) in order to obtain the required degree of smoothness and then buffing. designated 380 in FIG. 3, in order to bring the aluminium surface to a highly reflective and highly shiny state.

[0057] The highly polished and smooth aluminium surface is low friction and performs well in the water Although the aluminium on the bottom of the board is attractive in its highly polished state and performs well in the water, it may be desirable to leave portions of the board deck without such a mirror-like finish.

[0058] FIG. 4 shows a plan view of a preferred embodiment of a surf board in accordance with the present invention in which portions of the board deck have been left, or provided, with a relatively matt finish. The matt finish can be obtained by roughening the mirror-like surface or alternatively by omitting some of the polishing and/or buffing process so that the desired portions of the board are not brought to a polished surface.

[0059] As shown in FIG. 4, a first matt deck portion 410 is provided towards the front of the board, in order to avoid unwanted reflections from the board distracting or dazzling the user, especially at times when the user is lying upon the board (such as while waiting for a wave). Prevention of reflection of direct sunlight is particularly important. A second matt deck portion 420 is provided nearer the rear of the board in order to provide a higher friction surface for a surfer's feet than would be provided by a very smooth and highly polished deck surface. It is of particular importance that the deck portion where the surfer's rear foot would be positioned has a surface which provides some grip. Of course, it would be possible to thoroughly polish the entire board surface and provide additional matt and/or higher friction surfaces after the polishing process, for example by roughening, etching, spraying, fixing patches of appropriate material or providing grip pads.

[0060] Fins may be added if desired. Because the addition of fins to a traditional surf board, and the means of connecting are well known, and similar techniques and procedures could be used for addition of fins to a board in accordance with the present invention, this aspect will not be described in detail herein. However, it is worth noting that fins could be fitted before metal coating the blank, so that the fins could also be metal coated and have the same strength and appearance characteristics as the rest of the board. Alternatively, fins could be attached, for example using 2 pack adhesive, after metal coating of the board. Similarly, a leg leash anchor can be provided in a number of ways which will be evident to the person skilled in the art. In addition, paint or other decorative items or substances could be applied over the metallic skin of the board if desired.

[0061] A variation of the above described embodiment is illustrated in FIGS. 5, 6a and 6b. FIGS. 7a, 7b, 7c and 7d illustrate a preferred method for manufacturing the embodiment of FIGS. 5, 6a and 6b. FIG. 7d (which corresponds to the end of the manufacturing process illustrated by FIGS. 7a to 7d) may also be taken to be a partial illustration of the embodiment of FIG. 5. As in FIGS. 1 and 2, the thickness of the metallic layers has been exaggerated in FIGS. 5 to 7d.

[0062] The embodiment of FIG. 5, generally designated 500, is similar to the embodiment of FIGS. 1 and 2 but includes an expansion joint 505. In the preferred embodiment of this variation, the expansion joint 505 comprises a plastic band 510 (that is, a continuous band of a plastics material, e.g. nylon) which passes around the core 520 of a surf board blank. The band 510 is inset into a groove made in the foam core 520 of the blank (the groove is not shown in FIGS. 5, 6a, 6b but corresponds to the groove designated as 517 in FIGS. 7a to 7d). It may also be necessary to adapt the shape of the stringer to accommodate the band 510. The band 510 has an inner surface 511 which contacts the bottom of the groove 517 and an outer surface which is flush with an outer surface of an outer metallic layer 540 of the surf board. The plastic band 510 is preferably coloured so as to blend effectively with the outer metallic layer 540 of the surf board, or alternatively may be an aesthetically pleasing contrasting colour. The purpose of the plastic band 510 is to provide a discontinuity in the outer metallic layer 540 of the surf board in order to provide an expansion joint. The expansion joint 505 may be desirable in order to allow for the differential expansion of the core and the outer metallic skin, especially at times of rapid temperature changes such as when the board is taken from a hot sunny position (where the board temperature might reach 50 degrees centigrade) into water which might have a temperature of 20 to 25 degrees centigrade.

[0063] As shown in FIG. 6a, the board including such an expansion joint 505, preferably includes a stringer 525 which extends centrally along the length of the board in order to provide longitudinal strength thereto. As shown in FIG. 6b, a cross-section of the board which does not include the expansion joint 505 is generally similar to a cross-section of the board in accordance with the embodiment of FIG. 1. The board is shown in FIG. 6b as having a metallic inner layer 530 in the form of a zinc coating, an aluminium rail coating layer 535 and the above-mentioned aluminium outer metallic layer 540.

[0064] A method of manufacturing a board having an expansion joint 505 will now be described with reference to FIGS. 7a to 7d.

[0065] FIG. 7a shows a partial vertical cross-section through a part of a blank containing the plastic band 510 embedded in groove 517 in a foam core 520 of a blank. The groove 517 is preferably about 3 or 4 mm (0.12-0.16 inches) deep. The plastic band 510 has an inner surface 511 which contacts the bottom of the groove 517 and may be glued thereto with a suitable adhesive. The plastic band 510 extends outwardly out of the groove 517 so as to stand proud of the outer surface of the foam core 520. In this embodiment, it is important that the amount to which the plastic band 510 stands proud of the outer surface of the core 520 at any particular point is greater than the intended total thickness of the metallic coating(s) to be applied to the core. In this embodiment, it is ample for the band 510 to stand proud of the surface blank 520 by about 2 mm (0.08 inches).

[0066] As shown in FIG. 7b, a metallic inner layer 530 in the form of a zinc coating is applied to the outer surface of the core 520 in order to cover the core with zinc, as described above, and the zinc coating also covers the plastic band 510.

[0067] As shown in FIG. 7c, the metallic skin in the form of an aluminium outer layer 540 which is applied to the blank also covers the portion of the zinc inner layer which covers the plastic band 510. A rail coating layer may be applied to the blank 520, but this is not shown in FIGS. 7a to 7d.

[0068] Once the required metallic layers have been deposited, the board is smoothed/polished and buffed. As part of the smoothing/polishing process the plastic band 510 is abraded so that after being abraded its outer surface 512 is flush with the outer surface of the aluminium outer metallic layer 540 of the surf board.

[0069] Alternative methods of providing a plastic band 510 are of course possible. For example, the entire board could be coated by the metallic layers and an appropriate groove could then be routed, into which a plastic band could be fixed and then abraded so that its outer surface would be flush with the rest of the surf board outer surface.

[0070] It is possible that the provision of a plastic band to act as an expansion joint could create a weak area in the board and it could therefore be necessary or desirable to provide additional reinforcement of the blank in the region of the expansion joint, and preferably underneath the plastic band. Suitable means of reinforcing a foam blank will be known and/or evident to persons skilled in the art.

[0071] A potential problem of a metal coated board is its tendency to heat up rapidly if left in direct sunlight on a hot day. When immersed in water this will not be a problem since heat will be dispersed from the board into the water. The problem can be avoided by ensuring that the board is not left unprotected in direct sunlight. For example, use of a board cover would mitigate or alleviate this problem. It should be noted that conventional fibreglass covered surf boards cannot be left in hot sun for extended periods since fibreglass is vulnerable to ultra-violet light and the wax generally used to ensure grip on the deck of the surf board would melt at high temperatures. Thus surfers will be familiar with the necessity of avoiding prolonged exposure of their boards to the sun.

[0072] However, in order to facilitate the carrying of a hot board to the water, a portion of the board with low thermal conductivity may be provided. For example, a low thermal conductivity region may be integrated into the board upon manufacture by providing a band around the board similar to the plastic band used in the expansion joint described above, but having a width of approximately 10 to 15 cm (4 to 6 inches) as against the approximately 1 cm (0.4 inches) width of the expansion joint. Such a band portion could be used to carry a board to the water safely even if the outer metallic layer on other parts of the board were too hot to handle comfortably. Alternatively, a portion of the board surface could be coated, over the metallic skin, by a material with a low thermal conductivity in order to provide a portion for handling a hot board.

[0073] In addition to the above embodiments, further variations are possible. For example, in order to provide more longitudinal strength to the board and to help prevent hogging and sagging, a number of longitudinal grooves, extending the entire length of the board, may be made in the foam blank, for example by routing to a depth of approximately 2 mm (0.08 inches), and these grooves may then be filled with metal to provide additional longitudinal reinforcement. It is anticipated that the grooves would be filled with aluminium. This could be achieved after coating the blank with zinc either by lying strips of solid aluminium in the grooves above the zinc and then spraying with aluminium to secure the strips to the zinc, or merely by filling the grooves with sprayed aluminium. In a preferred variation, six longitudinal metal filled grooves are provided which extend substantially the full length of the deck and which are spaced across the width of the deck and six similar longitudinal metal-filled grooves are provided on the bottom of the board. Of course, the size, number and material used to fill such grooves may be varied as desired, taking into account the desired strength, weight and cost of the finished item.

[0074] A further modification is that the strength and/or feel of the board could be enhanced by providing connecting members in the form of pillars, rods or wires extending through the thickness of the board, between the metallic outer layers on the bottom surface of the board and the deck. Such a structure could be achieved by making a number of holes through the thickness of the foam core and inserting connecting members to fit snugly in the holes. It is envisaged that if the connecting members are made from the same material as the metallic outer layer (or if materials are such that good adhesion between them is possible), then the ends of the connecting members should be positioned such that upon application of the metallic outer layer the ends of the connecting members are covered and contacted by the metallic outer layer. It is envisaged that aluminium wire having a diameter of approximately 2 mm (0.08 inches) would be an appropriate material for the connecting members. In this case, after insertion of the required number of connecting members the entire blank could be zinc coated (as described above) and the length of the aluminium wires could be such that the ends thereof stand slightly proud of the zinc coating. The zinc coating could then be removed from the ends of the wires so that the aluminium sprayed on top of the zinc would directly contact the aluminium wires.

[0075] The provision of connecting members is considered to provide a more rigid connection between the board bottom and the deck, and thus to provide additional feel and responsiveness for the board.

[0076] The provision of metal connecting members would also help conduct heat away from the upper surface of the board.

[0077] The hardness, strength and density of the foam used for the core and the size and strength of the stringer would be chosen to be appropriate for the desired weight and strength of the finished board. An additional option for enhancing the rigidity of the board is to lightly coat the blank with an epoxy-type resin before application of the metallic skin, and in a preferred embodiment, before application of the zinc metallic inner layer.

[0078] The above described embodiments have considerable advantages in ease of manufacture over fibreglass boards, since the laying up of glass fibre sheets and resin is a difficult and time consuming task: although requiring more equipment, the spraying of a metal coating onto a foam blank may be performed considerably more quickly and easily. Furthermore, because the metallic skin (or total thickness of the metallic layers) is considerably thinner than fibreglass board coatings, the shape of the blank is more accurately reproduced in the finished board. This can be of particular benefit if the sportscraft to be manufactured has fine or complex contours such as might be required for some forms of sportscraft, since such fine detail is difficult or impossible to maintain when applying a glass fibre coating. The maintenance of contours and fine detail facilitates the provision of, for example, surf boards having contours, ridges or other features to assist control of the board. Boards having standard contours for a surfer to brace or push against are envisaged, as are custom-made boards with features provided according to the requirements of a particular surfer. For example, a surf board having small raised ridges around the part where a surfer's rear foot would be placed is envisaged.

[0079] Furthermore, the application of metal coatings of the type described requires little or no drying or curing time, in contrast to the considerable drying or curing time of glass fibre coatings. This reduces manufacture time and cost.

[0080] A further benefit of sprayed metal coatings is in the repair of damage which is sustained to the board. Repair of dings or cracks in glass fibre boards can be difficult and time consuming, especially if delamination has occurred and such repairs are generally difficult to conceal and leave a permanent blemish. In contrast, an area of an aluminium coated board which is repaired and resurfaced can be blended into the surrounding aluminium surface so as to make the repair virtually undetectable.

[0081] It is well known that aluminium is recyclable and this provides a further benefit over glass fibre boards, since glass fibre is not recyclable and disposal of waste glass fibre products is a cause for environmental concern.

[0082] It is envisaged that the average 6 ft aluminium coated board will require approximately 1.5 to 2 kgs (3.3 to 4.4 lbs) of aluminium, although the number and thickness of the coatings will depend on the weight, design and performance required of the finished board.

[0083] The final coating preferably encapsulates the entire board sealing it completely. The anti-corrosion properties of aluminium (and zinc) are well known and the aluminium coating is resistant to repeated immersion in a salt water environment, with minimal maintenance.

[0084] The aluminium provided commercially for use in flame guns is approximately 99% pure and has a hardness of about 80 Rh in comparison to a hardness of approximately 45 Rh of a typical laminating resin. The mechanical sensitivity to heat is lower for aluminium than for fibreglass resin and the volume shrinkage is also lower.

[0085] The extreme thinness of the metallic coating compared to fibreglass shell is predicted to provide a board with considerably more sensitivity than a fibreglass board allowing a surfer more feel, quicker reaction to wave conditions, more manoeuvrability, and a more satisfying surfing experience.

[0086] It is envisaged that the aluminium may also be treated in order to further enhance its desirable qualities. For example, it may be desirable to anodise some or all of the aluminium surface increasing the hardness of the surface, possibly reducing the friction of the surface, and also allowing dying of the surface in any of a number of bright colours in order to enhance the aesthetic appeal of the board. Alternatively, a clear lacquer could be applied over part or all of the board. It should be noted that although board-like sportscraft in accordance with the present invention are described as having a metallic outer layer, this is not intended to exclude those in which the metallic layer is further coated by a lacquer paint or other outermost coating.

[0087] Although aluminium is considered suitable for preferred embodiments of the board, it is envisaged that other metals could be used for the metallic skin covering the board without departing from the scope of the invention. For example, a board with a stainless steel coating has been envisaged which could be suitable for uses where the final weight of the board is not an important consideration, for example, for use on very large (eg. 10 m (33 ft)) waves. Furthermore, in such an application a stainless steel stringer could be used and it is envisaged that such a stringer could be in the form of a 1 mm (0.04 inch) plate generally conforming to the shape of a known stringer or could be in the form of one or more longitudinal stainless steel strips sprayed into grooves in the foam core.

[0088] In an aluminium covered board, it is also envisaged that an aluminium stringer could be used, and the form of such a stringer could be similar to the form of a stainless steel stringer described above.

[0089] Use of a sprayed metallic skin as an outer surface of a surf board can provide an extremely smooth, seam-free outer surface. Areas of increased metal thickness, such as at the rails, involve additional metal thickness of only fractions of a millimeter, and it is therefore considered possible to include them without noticeably affecting the shape or profile of the finished board. However, if necessary, the blank can be shaped to accommodate such areas of increased thickness, ensuring that the desired final shape can be attained. Preferred embodiments can thus provide reinforced rails in combination with a seamless skin. This is in contrast to fibreglass covered boards which may have seams, joins or overlays in the fibreglass material detracting from the unitary nature of the shell. Although a polished metallic finish is considered aesthetically desirable, it is, of course possible to lacquer, paint, etch or decorate by other means, embodiments of boards in accordance with the present invention. Use of a board with a metallic outer surface may also have important safety considerations since such a board could be highly reflective and this could be increase visibility and aid in the detection of persons or craft lost at sea. Such a board would also be considerably more easy to detect by radar and echo sounder than a glass fibre board. Such a board could provide an effective flotation device for emergency situations.

[0090] It can thus be seen that at least preferred embodiments of the present invention provide board-like sportscraft with considerable advantages over prior art craft. Preferred embodiments of board-like sportscraft in accordance with the present invention may have a number of advantages over fibreglass coated boards including one or more of the following:

[0091] greater resistance to dings;

[0092] avoidance of, or greater resistance to, delamination;

[0093] greater recyclability of materials used in construction (since the aluminium coating could be removed and reused at the end of the life of the board);

[0094] distinctive and/or enhanced aesthetic appeal;

[0095] enhanced ease of repair;

[0096] enhanced structural strength;

[0097] more feel;

[0098] a smooth “one-piece” finish, since the metallic outer skin can be formed smoothly and seamlessly; and

[0099] low maintenance, since waxing would not be required.

[0100] For the purposes of this specification it will be clearly understood that the word “comprising” means “including but not limited to”, and that the word “comprises” has a corresponding meaning.

[0101] It is to be clearly understood that any reference herein to a prior art publication does not constitute an admission that the document forms part of the common general knowledge in the art in Australia or in any other country.

Claims

1. A board-like sportscraft comprising a core and a metallic skin covering at least a portion of said core.

2. A board-like sportscraft as claimed in claim 1 wherein said metallic skin covers at least 75% of the surface of said core.

3. A board-like sportscraft as claimed in claim 2 wherein said metallic skin covers substantially all of said core.

4. A board-like sportscraft as claimed in claim 1 wherein said core includes two side rail portions and wherein the metallic skin covers at least 75% of each of said side rail portions.

5. A board-like sportscraft as claimed in claim 4 wherein said core includes a deck portion, a bottom surface portion and wherein the mean thickness of said metallic skin is greater on said side rail portions than on said deck portion and bottom surface portion.

6. A board-like sportscraft as claimed in claim 1 wherein there is provided a surface portion of the core which is not covered by said metallic skin, in order to mitigate or avoid damage to said board-like sportscraft due to differential thermal expansion between said metallic skin and said core.

7. A board-like sportscraft as claimed in claim 1 wherein the core includes surface features which are substantially reproduced in the metallic skin, and wherein the surface features are adapted to provide a user with enhanced grip or control.

8. A board-like sportscraft as claimed in claim 1 wherein at least some of the outer surface of the metallic skin is highly reflective.

9. A board-like sportscraft as claimed in claim 1 wherein there are provided one or more connecting members formed from a material having greater rigidity than the core, and wherein said connecting members pass through the core in order to enhance the rigidity of a connection between a bottom surface of said sportscraft and an upper surface of said sportscraft.

10. A board-like sportscraft as claimed in claim 1 wherein at least a portion of the outer surface of the metallic skin provides a high friction surface to facilitate grip by a user.

11. A board-like sportscraft as claimed in claim 1 wherein the metallic skin is composed mainly from a metal chosen from the group consisting of: aluminium; stainless steel; aluminium alloys.

12. A board-like sportscraft as claimed in claim 1 wherein there is provided an inner coating layer, between the core and the metallic skin, and said inner layer is composed of different material to said metallic skin.

13. A board-like sportscraft as claimed in claim 12 wherein said inner layer is provided in order to facilitate or enhance adhesion of said metallic skin to said core.

14. A board-like sportscraft as claimed in any preceding claim wherein said core is provided with a number of longitudinal grooves therein, and said longitudinal grooves are filled with a metallic substance in order to provide the board-like sportscraft with enhanced longitudinal strength.

15. A method of manufacturing a board-like sportscraft comprising the steps of:

preparing at least a portion of a shaped core for a board-like sportscraft for coating with a metallic skin;

coating at least a portion of said core with a metallic skin.

16. The method of claim 15 further including the step of coating said at least a portion of said core with an intermediate coating layer, and wherein said step of coating at least a portion of said core with a metallic skin comprises applying said metallic skin onto at least a portion of said intermediate coating layer.

17. The method of claim 16 wherein said intermediate coating layer is composed entirely or mainly of zinc.

18. The method of claim 15 wherein said metallic skin is formed from a substance composed entirely or mainly of a metal chosen from the group including: aluminium; aluminium alloy; stainless steel.

19. The method of any of claim 15 wherein said step of coating with a metallic skin includes spraying a metallic substance to form the metallic skin.

20. The method of claim 19 wherein the spraying of the metallic substance is performed by a thermal metal spray process.