US20040005825A1

US20040005825A1 - Board-like sportscraft

Info

Publication number: US20040005825A1
Application number: US10/250,263
Authority: US
Inventors: Ronald Hasted
Original assignee: Individual
Current assignee: Individual
Priority date: 2001-01-10
Filing date: 2003-06-18
Publication date: 2004-01-08

Abstract

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

Description

CROSS REFERENCE TO RELATED APPLICATIONS

This application is a Continuation-In-Part of U.S. application Ser. No. 10/043,360, filed Jan. 9, 2002, which claims the benefit of Australian Patent Application No. PR2473, filed Jan. 10, 2001. This patent application also claims the benefit of Australian Patent Application No. 2002300981, filed Sep. 11, 2002.[0001]

FIELD OF THE INVENTION

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

BACKGROUND OF THE INVENTION

Conventional board-like sportscraft such as surfboards 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.

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 surfboards 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, conventional fibreglass boards suffer from a structural weakness which may cause portions of the board to sag or hog.

SUMMARY OF THE INVENTION

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.

Preferably the sportscraft is for use on water. Sportscraft for use on water include surfboards, sail boards, boogie boards, knee boards, body boards and surf skis.

Preferably, the metallic skin contributes substantially to the structural strength of the sportscraft.

Preferably, said metallic skin covers at least 75% of the surface of said core. Alternatively the metallic skin may be selected to cover any desired proportion of the core.

Said metallic skin may cover substantially all of said core.

Preferably, said core includes two side rail portions and the metallic skin may cover at least 75% of each of said side rail portions.

Preferably, said core includes two side rail portions and wherein the metallic skin does not extend over the side rail portions, and wherein the said rail portions of the core are covered by a fibre composite material.

Preferably, said core includes a deck portion, and a bottom surface portion and in one embodiment 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.

There may be 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.

The core may include surface features which are substantially reproduced in the metallic skin, and the surface features may be adapted to provide a user with enhanced grip or control of the craft.

Said board-like sportscraft may be a surfboard, and said features may be provided on or adjacent the deck and/or rails of the surfboard.

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

Preferably, at least a portion of the outer surface of the metallic skin is non-reflective and most preferably the 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.

There may be provided one or more connecting members formed from a material having greater rigidity than the core, and said connecting members passing 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.

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

Enhancing the rigidity of the connection between upper and lower surfaces may be desirable in order to improve the feel of the sportscraft.

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 surfboard, a bottom portion of the board is preferably provided with such a surface.

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 surfboard, a portion of the board deck is preferably provided with such a surface.

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

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.

Preferably, said inner layer is provided in order to enhance adhesion of said metallic skin to said core.

The inner layer may include a substantial zinc component.

The inner layer may be composed mainly or substantially entirely of zinc.

The inner layer may comprise an adhesive.

The inner layer may comprise an epoxy resin material.

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.

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.

At least some of said metallic skin may be formed by spraying of a metal.

Said core may include at least one side rail portion. The metallic skin may cover at least part of the at least one side rail portion. The side rail portion of the metallic skin may be formed by spraying of a metal.

Preferably, at least some of the metallic skin is formed from one or more prefabricated metallic panels.

Preferably, more than half of the surface area of the outer surface of the metallic skin is formed from one or more prefabricated metallic panels.

Preferably, at least a portion of the core which is not covered by a metallic panel is covered by a skin portion made of a composite material.

Preferably, not more than half of the surface area of the outer surface of the metallic skin is formed by spraying of a metal onto said core.

At least one of said one or more metallic panels may include at least one fin.

At least one of said one or more metallic panels may include at least three fins.

Preferably, at least one of said one or more metallic panels includes at least one fin attachment portion for attachment of at least one fin thereto.

Preferably, said attachment portion includes a fin base portion.

One or more metallic panels may be in the form of at least a portion of a shell, and the core may have been formed by introducing a fluid into said shell and allowing the fluid to set to form the core.

According to a second aspect of the present invention, there is provided 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; and

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

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.

The intermediate coating layer may be composed entirely or mainly of zinc, and/or may include an adhesive, and/or epoxy resin material.

Preferably, said metallic skin is formed from a substance composed entirely or mainly of a metal chosen from the group including: aluminum; aluminum alloy; stainless steel. Other metallic materials, such as magnesium alloys, could be used to form at least part of the metallic skin.

Preferably, said core is formed from a foam material.

Said step of coating with a metallic skin may include spraying a metallic substance to form the metallic skin.

Spraying of the metallic substance may be performed by a thermal metal spray process.

Preferably, the step of coating with a metallic skin includes the step of attaching one or more prefabricated metallic panels to the core.

One or more prefabricated panel may include a fin.

Preferably, the step of attaching one or more prefabricated metallic panels to the core includes use of pressure exerted by a fluid to force at least one panel onto the core.

Preferably, the step of attaching one or more prefabricated metallic panels to the core includes placing the core and panel(s) into a flexible container and at least partially evacuating the container so that the external air (fluid) pressure forces at least part of the container to bear upon at least one panel, forcing the panel onto the core. Alternatively, one or more chambers may be provided near the core and at least one panel, so that increase in fluid pressure effects application of pressure onto the panel.

According to a third aspect of the present invention there is provided a method of manufacturing a board-like sportscraft comprising the steps of:

forming a shell including at least one metal portion;

introducing a fluid into said shell;

allowing the fluid to set so as to form a core of a sportscraft, and so that the shell forms a skin which covers at least part of said core, and at least part of said skin is metallic.

It will be appreciated that certain features which may be usefully incorporated in one aspect of the present invention might also be usefully incorporated into other aspects.

BRIEF DESCRIPTION OF THE DRAWINGS

Embodiments of the present invention will now be described, by way of example only, with reference to the accompanying drawings in which: [0061]
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 surfboard; [0062]
FIG. 2 shows schematically a cross-section of the rail section of the embodiment of FIG. 1 in greater detail; [0063]
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 surfboard; [0064]
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 surfboard, showing schematically areas of the surfboard having different surface finishes; [0065]
FIG. 5 is a plan view of a variation of the embodiment of FIG. 1; [0066]
FIG. 6[0067] a is a cross-sectional view on VIa-VIa of FIG. 5;
FIG. 6[0068] b is a cross-sectional view on VIb-VIb of FIG. 5;
FIGS. 7[0069] a to 7 d are partial cross-sectional views illustrating the manufacture of the embodiment of FIGS. 5 and 6;
FIG. 8 is a plan view illustrating schematically the structure of an embodiment of a surfboard; [0070]
FIG. 9 is a cross-sectional view on IX-IX of FIG. 8; [0071]
FIG. 10 is a schematic partial cross-sectional view illustrating a method of constructing a surfboard; [0072]
FIG. 11 is a schematic partial cross-sectional view illustrating an alternative structure for a surfboard; and [0073]
FIGS. 12A, 12B and [0074] 12C are vertical cross-sectional views illustrating schematically attachment of a surfboard fin to a fin base in an embodiment of the present invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

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 surfboard generally designated [0075] 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 surfboard core. The core 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 core, a rail coating layer 30 of a second metal is provided. In a preferred embodiment, the second metal is aluminum. A metallic skin in the form of an outer metallic layer 40, preferably composed of aluminum, 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.
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 aluminum 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 surfboard. The [0076] aluminum 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 aluminum does not noticeably deteriorate when exposed to seawater as does fibreglass.
The application of aluminum may also be quicker and more easily performed than the application of fibreglass to a surfboard core and the provision of the [0077] rail coating layer 30 in addition to the outer metallic layer 40 provides a double layer of aluminum along the rails of the board which provides additional strength to these 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 40 are, for clarity, shown to be quite thick compared to the thickness of the core 10. 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.
With reference to FIG. 3, a method of manufacturing an embodiment of a board-like sportscraft, in the form of a surfboard, will hereafter be described. [0078]
A first step in the process, designated [0079] 310 in FIG. 3, is to begin with a surfboard core shaped appropriately for the desired finished board. The next step, designated 320 in FIG. 3, is to treat the surface of the shaped core 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 core. 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 (0.01 to 0.03 inches).
A third step, designated [0080] 330 in FIG. 3, comprises coating the prepared core with an inner layer (or intermediate coating layer), in this case a layer of 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 core.
Coating of the core 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 core 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 core in this way without noticeably heat-damaging the core. Zinc wire especially suited for use as a primer or undercoat for aluminum 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. [0081]
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 surfboard core, it is desirable in this embodiment that the entire surface of the core is provided with the zinc coating. As the surfboard core 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. [0082]
The next step, designated [0083] 340 in FIG. 3, is to prepare the zinc for coating with aluminum. 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 aluminum layer.
The next step, designated [0084] 350 in FIG. 3, is to coat the edges or rails of the board with aluminum 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.
The next step, which is the final constructional step in this embodiment, and is designated [0085] 360 in FIG. 3, is to coat the entire board surface (including the already-coated rails) with aluminum 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 core and providing a surface which is aesthetically highly pleasing.
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 course, 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. [0086]
The aluminum coating then undergoes the step of polishing, designated [0087] 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 aluminum surface to a highly reflective and highly shiny state.
The highly polished and smooth aluminum surface is low friction and performs well in the water. Although the aluminum 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. [0088]
FIG. 4 shows schematically a plan view of a preferred embodiment of a surfboard 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. [0089]
As shown in FIG. 4, a first [0090] 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.
Fins may be added if desired. Because the addition of fins to a traditional surfboard, and the means of connecting are well known, and similar techniques and procedures could be used for addition of fins to the above described embodiment of a board in accordance with the present invention, this aspect will not be described in detail in relation to this embodiment. However, it is worth noting that fins could be fitted before metal coating the core, 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. A variation of the above described embodiment is illustrated in FIGS. 5, 6[0091] a and 6 b. FIGS. 7a, 7 b, 7 c and 7 d illustrate a preferred method for manufacturing the embodiment of FIGS. 5, 6a and 6 b. FIG. 7d (which corresponds to the end of the manufacturing process illustrated by FIGS. 7a to 7 d) 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 7 d.
The embodiment of FIG. 5, generally designated [0092] 500, is similar to the embodiment of FIGS. 1 and 2 but includes an expansion joint 505. In a 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 surfboard core. The band 510 is inset into a groove made in the foam core 520 (the groove is not shown in FIGS. 5, 6a, 6 b but corresponds to the groove designated as 517 in FIGS. 7a to 7 d). 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 surfboard. The plastic band 510 is preferably coloured so as to blend effectively with the outer metallic layer 540 of the surfboard, 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 surfboard 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.
As shown in FIG. 6[0093] a, 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 aluminum rail coating layer 535 and the above-mentioned aluminum outer metallic layer 540.
A method of manufacturing a board having an [0094] expansion joint 505 will now be described with reference to FIGS. 7a to 7 d.
FIG. 7[0095] a shows a partial vertical cross-section through a part of a core containing the plastic band 510 embedded in groove 517 in a foam core 520 of a core. 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 core 520 by about 2 mm (0.08 inches).
As shown in FIG. 7[0096] b, 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.
As shown in FIG. 7[0097] c, the metallic skin in the form of an aluminum outer layer 540 which is applied to the core also covers the portion of the zinc inner layer which covers the plastic band 510. A rail coating layer may be applied to the core 520, but this is not shown in FIGS. 7a to 7 d.
Once the required metallic layers have been deposited, the board is smoothed/polished and buffed. As part of the smoothing/polishing process the [0098] plastic band 510 is abraded so that after being abraded its outer surface 512 is flush with the outer surface of the aluminum outer metallic layer 540 of the surfboard.
Alternative methods of providing a [0099] 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 surfboard outer surface.
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 core in the region of the expansion joint, and preferably underneath the plastic band. Suitable means of reinforcing a foam core will be known and/or evident to persons skilled in the art. [0100]
Many variations of the above embodiments are, of course, 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 core, 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. The grooves could, for example, be filled with aluminum. This could be achieved after coating the core with zinc either by laying strips of solid aluminum in the grooves above the zinc and then spraying with aluminum to secure the strips to the zinc, or merely by filling the grooves with sprayed aluminum. 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. [0101]
The final coating may encapsulate the entire board, sealing it completely. The anti-corrosion properties of aluminum (and zinc) are well known and the aluminum coating is resistant to repeated immersion in a salt water environment, with minimal maintenance. [0102]
The aluminum 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 aluminum than for fibreglass resin and the volume shrinkage is also lower. [0103]
Although it is possible to metal spray substantially an entire board-like sportscraft, as set out in the above described embodiments, it is currently preferred to provide at least a part of the metallic skin in the form of one or more prefabricated metallic panels. The use of one or more prefabricated metallic panels can considerably reduce or eliminate the requirement of spraying a surfboard, thus reducing labour costs in production. Manufacturing a metallic, and in preferred embodiments aluminum, panel from sheet metal also allows greater flexibility of manufacturing technique, allowing a stronger and more rigid metallic layer,.for a given thickness and weight, than can readily be achieved by a metal spray process. [0104]
The embodiment of FIGS. 8 and 9 provides a board-like sportscraft in the form of a surfboard generally designated [0105] 600 which includes on its upper surface a metallic skin portion in the form of a metallic panel 610 which covers most of an upper surface of a surfboard core 612. The board 600 includes first and second rail portions 620, 621 along the edges thereof. The metallic panel 610 extends close to but not vertically around the rail portions 620, 621. A metallic skin may be applied to the rail portions 620, 621 by a metallic spray process.
It should be noted that the illustration of FIGS. 8 and 9 is not to scale. In a preferred embodiment, the [0106] metallic panel 610 extends to approximately 30 mm (1.2 inches) from the edges of the deck part of the foam core 612, thus greatly reducing the surface area to be sprayed in order to provide a continuous metallic skin forming substantially the entire surface of the board. A metallic bottom panel 614 may similarly be applied to the bottom of the core 612. Metallic panels forming metallic skin portions may, in preferred embodiments, constitute fifty percent or more of the surface of the board, and in preferred embodiments may constitute over seventy-five percent or even approximately ninety percent, of the board surface.
A preferred method of attaching upper and lower [0107] metallic panels 610, 614 to a surfboard core will now be described. A suitably prepared surfboard blank or core 612 is provided. A suitable adhesive, preferably an epoxy based adhesive is applied to the core 612 covering at least the regions which will be covered by the upper and lower metallic panels 610, 614. Alternatively, or additionally, the adhesive could be applied to the panels or to the panels and the core. The upper and lower metallic panels 610, 614 are positioned against the core 612 (with the adhesive therebetween). Pressure is then applied to the metallic panels 610, 614 forcing them against the core 612 and causing the respective shapes of the panels 610, 614 to conform closely to the shape of corresponding parts of the core 612. The pressure is preferably maintained until the adhesive has adequately set or cured. Furthermore, the pressure is preferably adequate to spread the adhesive between the panels and the core, and to force some of the adhesive out around the edges of the metallic panels 610, 614 so that a thin, even, effective layer of adhesive remains.
A preferred method of applying pressure to the [0108] panels 610, 614 is to place the core 612, with the panels 610, 614 positioned thereon, in an airtight bag or envelope having respective internal faces which may bear upon respective upper and lower panels 610, 614. Evacuation of the air from the bag or envelope results in the internal faces applying considerable pressure upon the metallic panels 610, 614. In utilising such a method a lining material, preferably a textile material may be placed so that, in use, the lining material lies between each of the panels 610, 614 and the respective internal faces of the bag or envelope. Such a material is preferably suitable for absorbing extraneous or superfluous adhesive (preferably epoxy based adhesive). A release material is preferably also provided so that it isolates the lining material from the internal faces of the bag or envelope. Evacuation of the envelope or bag may be maintained for a considerable length of time, typically six hours, to provide adequate adhesion of the panels 610, 614 to the core 612 and to ensure that the panels are adequately shaped to conform to the shape of the core. If such a process is used any foam core used should be sealed, for example by coating with epoxy, in order to avoid damage to the foam structure being caused by the low pressure.
In the illustrated embodiment, the bottom surface of the core has a double concave form. Such a form of bottom surface is preferred by some surfers but, of course, other forms may be used. In the embodiment of FIGS. 8 and 9, no zinc inner layer is required on the portions of the core which will be covered by the [0109] metallic panels 610, 614. However, the adhesive may be considered an inner layer or intermediate layer which facilitates adhesion of the metallic skin in the form of the panels 610, 614 to the core 612.
After the [0110] panels 610, 614 are adhered to the core, a metallic skin may be applied to the rail portions 620, 621 by metal spraying as described above. A zinc coating (not shown in FIGS. 8 and 9) may be provided as an intermediate layer between the core 612 and the metallic skin on the rail portions 620, 621. Alternatively (and more preferably), the adhesion of sprayed metal to epoxy has been found to be good and an intermediate layer formed of epoxy may be provided for the rail portions. As a further option, the thickness of the skin on the rail portions 620, 621 may be provided by alternating layers of epoxy and layers of sprayed metal in order to provide a robust laminated rail portion. Alternatively or additionally, aluminum mesh may be bonded to the rail portions of the core at the same time (and in the same manner) as the panels 610, 614 are bonded to the core. The provision of a metallic mesh, (and especially a mesh bonded to the core by an adhesive such as epoxy) between the core and sprayed aluminum skin assists adhesion and robustness of the rail portions of a preferred embodiment. A metallic skin may be formed covering the front and rear portions (or nose portion and tail portion) of the sportscraft, in the same way as for the rail portions.
It has been found that providing large metallic panels adhered to a foam core can provide a board-like sportscraft of very high rigidity. Indeed, the rigidity may be higher than is desirable for a surfboard. In order to overcome this, a plurality of slightly longitudinally spaced apart panels may be used on each of the upper and lower surfaces of the core in order to avoid excessive longitudinal rigidity. Alternatively, a number of apertures or slots may be provided in the metallic panels in order to provide an area of flexibility thereon. A laterally extending row of apertures is designated [0111] 630 in FIG. 8 by way of illustration. Surfboards formed in this way can be provided with or without a stringer, and in a board with a stringer, the stringer may be divided into two or more longitudinally spaced apart stringer segments in order to avoid excessive longitudinal rigidity. Of course, the rigidity of the board will depend upon a number of factors including the structural characteristics of the core and the thickness and composition of the metal skin.
It will be appreciated that the embodiment of FIGS. 8 and 9 and the accompanying description is illustrative only and many variations upon the shape of the panels and the method of manufacture of a board-like sportscraft with such panels are possible. [0112]
The provision of metallic panels conforming generally to the shape of the core but dimensioned slightly smaller than the core in width and length, allows a substantial portion of the core to be covered by the panels, considerably reducing the remaining surface area to be fabricated. [0113]
Although not essential, in some embodiments all or most of the board which is not covered by the metallic panels is covered by a sprayed metallic skin. In other embodiments it might be desired to have a smaller proportion of the core covered by the metallic skin. Embodiments are envisaged in which 50%, 60%, 75%, 95% and substantially the entire core is covered. [0114]
In embodiments in which both one or more metallic panels and also sprayed metal portions are provided, in order to ensure a good join between the sprayed metallic skin and a metallic panel, the edges of the panel may be slightly feathered, tapered or bevelled, or a transition piece having a thickness smaller than the thickness of the panel may be provided around the edge of the panel. Such a transition piece might have a thickness of 0.2 mm compared to a mean panel thickness of about 0.6 mm. Additionally or alternatively, as illustrated in FIG. 10, a [0115] panel 610 may be provided with a wire or bead 616 in a similar metal around the periphery thereof. By flame spraying onto the bead 616, in a direction away from the centre of the panel 610, it is possible to spread the bead 616, effectively blending the panel 610 and sprayed part (not shown) of the metallic skin. By way of illustration, arrow 618 in FIG. 10 illustrates a preferred direction for flame spraying aluminum in this way. FIG. 10 should be regarded as illustrative only, and in one embodiment the panel 610 is 0.6 mm thick and the bead 616 is 1.6 mm in diameter. As a further alternative, the panel could be formed with a raised ridge around the periphery thereof, to substitute for the bead 616.
In one embodiment, a 400 g polystyrene core is used, approximately 200 g of epoxy is used and approximately 1.5 kg to 2 kg (3.3 pounds to 4.4 pounds) of aluminum is used giving a total board weight of about 2.1 kg to 2.6 kg (about 4.5 pounds to 6 pounds). [0116]
In some embodiments, rather than metal spraying the surface portions of the board which are not covered by metallic panels, it is preferred to use a fibreglass or carbon fibre covering. Part of such a board, including a rail portion of such an embodiment, is schematically illustrated in cross-section in FIG. 11. [0117]
As illustrated schematically in FIG. 11, an embodiment of a surfboard includes a [0118] foam core 631, an aluminum upper deck panel 633, an aluminum lower deck panel 635 and a fibreglass (or carbon fibre) rail covering portion 637, which extends around the rail portion of the core and extends between the upper and lower deck panels 633, 635.
In a preferred embodiment, the fibreglass rail covering portion is provided by using a glass fibre mat in the form of a strip approximately 10 cm (4 inches) wide. The strip is laid up on the rail portions of the board (and around the front and rear of the board) using a suitable setting material. [0119]
In a preferred embodiment, each layer of fibreglass matting has a weight of about 0.2 kg/m2 (about 0.6 to 0.7 ounces per square foot) and two layers of the strip are provided around the entire circumference of the core. This provides a fibreglass layer approximately 0.6 mm (0.024 inches) thick around the edge of the core. The fibreglass layer may then be treated by an abrasive smoothing process such as, for example, sanding, before attaching the upper and [0120] lower deck panels 633, 635 to the core. In a preferred embodiment, the deck panels 633, 635 are attached to the core by an epoxy adhesive (which bounds readily to aluminum) using approximately 80 g (about 2.8 ounces) of adhesive for each panel. The panels are preferably attached by vacuum forming the deck panels 633, 635 to the core and to the fibreglass rail covering portions, in a manner corresponding to that described above in relation to the embodiment of FIGS. 8 and 9. The deck panels 633, 635 are dimensioned so that they slightly overlap the fibreglass rail covering portions, so that the edges of the fibreglass strip (or strips) are secured firmly between the edges of the deck panels 633, 635 and the core 631. The deck panels are preferably approximately 0.4 mm (0.016 inches) thick, but of course, this thickness could be varied according to the desired weight and characteristics of the board. The deck panels 633, 635 are preferably preformed with respective peripheral stepped sections 634, 636 to accommodate the edges of the fibreglass rail portions, and preferably correspond generally in size and shape to the top and bottom decks of the core, but in this embodiment are slightly smaller so that they to not extend onto the rail portions of the core. In a preferred embodiment, the fibreglass (or carbon fibre) of the rail portions, includes an upper deck portion 638 which extends approximately 35 mm (1.4 inches) onto the upper surface of the board, and a lower deck portion 639 which extends about 25 mm (1 inch) onto the lower surface of the board. The considerable strength and rigidity imparted to the board by the metallic skin portions in the form of the upper and lower deck panels 633, 635 reduces the structural strength required of the fibreglass rail covering portions, compared to traditional boards having cores covered entirely with fibreglass, so the fibreglass covering on the rail portions may, if desired, be thinner than in many known boards. Because the thickness of the deck panels 633, 635 and the fibreglass rail covering portions are small, the overlap where the edges of the deck panels 633, 635 overlay the edges of the fibreglass mat are not conspicuous. However, if required, suitable blending and/or shaping of the fibreglass rail portions, deck portions and/or core could be performed to provide an inconspicuous and/or aesthetically pleasing join.
The fibreglass rail covering portions and the deck panels may be treated, so that they are visually continuous, for example by spraying of the rail portions and possibly the deck panels so that the rail portions match the finish of the deck portions. Alternatively, the rail portions may be painted to contrast with the deck panels: blue or red rail portions have been found to contrast pleasingly with a metallic finish of the deck portions. [0121]
Of course it will be appreciated that the embodiments illustrated by FIGS. [0122] 8 to 11 are merely illustrative of many possible ways of providing a board-like sportscraft having a metallic skin provided at least partially by one or more preformed panels attached to a core. It will be evident that many variations and alternatives are possible, and are not intended to fall outside the scope of the present invention. For example, one possibility is to provide one or more moulds and to form a metallic shell, or panels which could be joined to form a shell, using the mould. Once the metallic shell is substantially complete, a core would be formed by injecting or otherwise introducing an expandable and/or settable fluid or foam inside the shell. Allowing setting of the foam into a solid would provide a robust board-like sportscraft in which the shell forms a metallic skin covering at least part of the core. Such a shell could be moulded in one of many ways known per se for performing or shaping metal panels, and could be formed in two or more parts which would be joined to form the metallic shell. Any apertures required for introduction of the fluid or foam could subsequently be plugged and/or closed and treated to give a suitable aesthetically pleasing finish. In an alternative method of construction, stamped (or otherwise formed) metal panels which include side rail covering portions could be attached, for example by epoxy adhesive, to a preformed solid foam core or blank of complementary shape. Using moulded or stamped metallic panels which include rounded edge portions to form the rails of, for example, a surfboard is desirable for mass production of embodiments of sportscraft in accordance with the present invention, since it eliminates or greatly reduces time consuming manual formation of curved rail parts. However, the tooling costs associated with producing such panels are high, and for low-volume manufacture, and in the manufacture of custom-made boards, it is currently considered more cost effective to use substantially flat metallic panels, which may be vacuum formed onto a blank to conform to the shape of the blank, and to manually form the rails, for example by metal spraying or laying up of fibreglass (or carbon fibre) material as described above.
In addition to reducing labour requirements, the provision of at least part of a metallic skin in the form of one or more preformed panels allows preformed features to be included on the metallic skin of the board. An important benefit of this is that fins may be formed on, for example, panels to be used on surfboards. Panels including fins may then be combined with a core in order to provide a finished product. [0123]
In one embodiment, an entire fin, for example approximately 10 cm (4 inches) long, is stamped into a metallic panel for use in forming the skin of a surfboard. Since a stamping process leaves a cavity in the panel, it is desirable to fill the cavity before completion of the product, preferably by filling with a low density material (such as a settable foam) prior to attachment of the panel to a board core. [0124]
In an alternative embodiment, rather than stamping a whole fin into a panel, only a partial fin or fin base is stamped into a panel and attachment means is provided for attaching the rest of the fin to the fin base. FIGS. 12A to [0125] 12C illustrate alternative vertical cross-sectional profiles for allowing attachment of a fin portion to a fin base provided on a panel. The orientation of the drawings is such that the fins are shown to project upwardly, since this is the most likely orientation for fitting the fins. Of course, in use, the fins would be more likely to project downwardly.
FIG. 12A shows a [0126] fin base 730A provided on a metallic panel 710A which, in use, forms part of a metallic skin for a board-like sportscraft.
The [0127] fin base 730A includes first and second fin sides 732A, 734A. The first fin side 732A extends a shorter distance from the generally planar surface of the panel 710A than does the second fin side 734A, and a stepped portion 736A is provided therebetween. A fin 750A includes first and second fin sides 752A, 754A and includes a complementary stepped portion 756A adapted for cooperation with the stepped portion 736A of the fin base 730A. In use, the stepped portions cooperate so that the respective first fin sides 732A and 752A of the fin base 730A and the fin 750A respectively, are generally coplanar. Also, the second fin sides 734A and 754A of the fin base 730A and the fin 750A are generally coplanar. A fixing member 760A fixes and locks together the fin base 730A and the fin 750A. In the embodiment of FIG. 12A, the fixing member passes through aligned apertures 759A, 739A in the fin 750A and fin base 730A, respectively.
FIG. 12B shows a variation in which the stepped portion of the base [0128] 736B includes two substantially parallel laterally extending edge portions and a raised central portion and the cooperating stepped portion 756B of the fin 750B includes two parallel lateral portions and a recessed central portion for cooperation with the stepped portion 736B of the fin base 730B.
FIG. 12C shows a variation on the embodiment of FIG. 12B which includes a male dove-tail shaped central section of the stepped portion [0129] 736C of the fin base 730C and a complementary cooperating female dove-tail shaped central section of the stepped portion 756C of the fin 750C. It will be appreciated that the dove tail shape of FIG. 12C provides for a more secure fixing of the fin 750C to the fin base 730C, but is more complex to manufacture. The embodiment of FIG. 12C would require the fin 750C to be slid longitudinally onto the fin base 730C. It will be appreciated that many alternative variations and embodiments in providing a metallic panel including a fin base for attachment to a fin may be provided, and that FIGS. 12A to 12C are somewhat schematic in nature. In a preferred embodiment, a self-locking grub screw is used as a fixing member to secure a fin to a fin base. Furthermore, it will be appreciated that it is important to fix the fin 750A, 750B, 750C securely and rigidly relative to the rest of the board so a secure fit, a secure fixing and/or a plurality of fixing members may be required for each fin. A preferred embodiment provides three fins or fin bases on a single panel but of course more or fewer could be provided. An advantage of two-part fins is facilitated transportation of the craft.
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 is unlikely to 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 surfboards 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 surfboard would melt at high temperatures. Thus surfers will be familiar with the necessity of avoiding prolonged exposure of their boards to the sun. [0130]
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. In an embodiment such of that of FIG. 11, in which the rails are made of a material with low thermal conductivity, handling of a hot board by the rails may be a convenient option. [0131]
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. If the connecting members are made from the same material as a sprayed metallic outer layer (or if a sprayed outer layer is used and the 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 sprayed metallic outer layer. Alternatively, adhesive bonding of the connecting members to the outer layer may be provided. Aluminum wire having a diameter of approximately 2 mm (0.08 inches) would be an appropriate material for the connecting members. [0132]
In the case of a board provided with a sprayed aluminum skin, after insertion of the required number of connecting members the entire core could be coated with zinc or another intermediate layer and the length of the aluminum wires should be such that the ends thereof stand slightly proud of the surface of the intermediate layer. The intermediate layer could then be easily removed from the ends of the wires so that a metallic skin sprayed on top of the intermediate layer would directly contact the aluminum wires. [0133]
The provision of connecting members can provide a more rigid connection between the board bottom and the deck, and thus to provide additional feel and responsiveness for the board. [0134]
The provision of metal connecting members would also help conduct heat away from the upper surface of the board. [0135]
The hardness, strength and density of the foam used for the core and the size and strength of the stringer (if any) would be chosen to be appropriate for the desired weight and strength of the finished board. In preferred embodiments, polystyrene foam is used, but if desired other materials, such as polyurethane foam, could be substituted. In one embodiment, a blank is made mainly from polystyrene, but is provided with polyurethane rail portions for increased strength. An option for enhancing the rigidity of the board (if desired) is to lightly coat the core with an epoxy-type resin before application of the metallic skin (and, if appropriate, before application of any zinc or other metallic inner or intermediate layer). Thermal treatment, for example gentle application of a flame, could also be used to collapse foam cells at the surface of a foam blank, providing a harder and higher density surface. [0136]
At least some preferred embodiments have considerable advantages over fibreglass boards, since the laying up of glass fibre sheets and resin over a large area is a difficult, time consuming and environmentally unfriendly procedure. Speed and ease of construction may be enhanced by the use of one or more metallic panels. Furthermore, in the case of a sprayed metallic coating, because the metallic skin (or total thickness of the coating layers) is considerably thinner than in many prior art fibreglass board coatings, the shape of the core may be 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, surfboards 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 possible, as are custom-made boards with features provided according to the requirements of a particular surfer. For example, a surfboard having small raised ridges around the part where a surfer's rear foot would be placed is possible. [0137]
A further benefit of a board with a metallic skin 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 aluminum skin of a board which is repaired and resurfaced can be blended into the surrounding aluminum surface so as to make the repair comparatively inconspicuous. In the case of, for example, a surfboard including a metallic panel to form at least part of a deck, in some embodiments the metallic panel could be removed and replaced as a unit, facilitating repair of damage to the deck of the board. [0138]
It is well known that aluminum 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. [0139]
In preferred embodiments, the average 6 ft aluminum coated board will require approximately 1.5 to 2 kgs (3.3 to 4.4 lbs) of aluminum, although the number of coatings and/or thickness (and hence weight) of the metallic skin will depend on the weight, design and performance required of the finished board. [0140]
The metallic skins of preferred embodiments of boards in accordance with the present invention may be thin compared to a fibreglass shell of a conventional board. This can 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. In one embodiment a metallic skin portion made of a material which can be magnetically attracted is provided in the position where, in use, a user's feet will be placed. Footwear with a magnetic sole can then be used to provide secure location of the user's feet. [0141]
The metallic skin, and in particular aluminum, may be treated in order to further enhance its desirable qualities. For example, it may be desirable to anodise some or all of the aluminum surface increasing the hardness of the surface, possibly reducing the friction of the surface, and also allowing dyeing 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 or skin, this is not intended to exclude those in which the metallic layer is further coated by a lacquer, paint or other outermost coating. [0142]
Although aluminum is used for preferred embodiments of the board, other metals could be used for the metallic skin without departing from the scope of the invention. For example, a board with a stainless steel skin 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 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. [0143]
In an aluminum covered board, an aluminum stringer could be used, and the form of such a stringer could be similar to the form of a stainless steel stringer described above. [0144]
Use of a metallic skin (and especially one provided by a process including spraying metal) as an outer surface of a surfboard 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 millimetre, and it is therefore considered possible to include them without noticeably affecting the shape or profile of the finished board. However, if necessary, the core can be shaped to accommodate such areas of increased thickness, ensuring that the desired final shape can be attained. Embodiments of the present invention 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. [0145]
It can thus be seen that at least some embodiments of the present invention provide board-like sportscraft with considerable advantages over prior art craft. At least some 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: [0146]
greater resistance to dings; [0147]
avoidance of, or greater resistance to, delamination; [0148]
greater recyclability of materials used in construction (since the aluminum coating could be removed and reused at the end of the life of the board); [0149]
distinctive and/or enhanced aesthetic appeal; [0150]
enhanced ease of repair; [0151]
enhanced structural strength; [0152]
more feel; [0153]
a smooth “one-piece” finish, since the metallic outer skin can be formed smoothly and seamlessly; and [0154]
low maintenance, since waxing would not be required. [0155]
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 any country. [0156]
Modifications and improvements may be incorporated without departing from the scope of the present invention. [0157]

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 the metallic skin contributes substantially to the structural strength of the sportscraft.

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

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

5. 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.

6. A board-like sportscraft as claimed in claim 1, wherein said core includes two side rail portions and wherein the said rail portions of the core are covered by a fibre composite material, and wherein the metallic skin does not extend over the side rail portions.

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

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

9. A board-like sportscraft as claimed in claim 8, wherein said inner layer includes at least one of: a zinc component; an adhesive; and an epoxy resin.

10. A board-like sportscraft as claimed in claim 1, wherein at least some of said metallic skin is formed by spraying of a metal.

11. A board-like sportscraft as claimed in claim 1, wherein at least some of the metallic skin is formed from one or more prefabricated metallic panels.

12. A board-like sportscraft as claimed in claim 11, wherein more than half of the surface area of the sportscraft is formed from one or more prefabricated metallic panels.

13. 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.

14. The method of claim 13 further comprising the step of coating 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.

15. The method of claim 14 wherein said intermediate coating layer is composed entirely or mainly of a substance chosen from the group including zinc; adhesive; epoxy resin.

16. The method of claim 13, wherein said metallic skin is formed from a substance composed entirely or mainly of a metal chosen from the group including: aluminum; aluminum alloy; stainless steel.

17. The method of claim 13, wherein said step of coating with a metallic skin includes spraying a metallic substance to form at least part of the metallic skin.

18. The method of claim 14, wherein said step of coating with a metallic skin includes the step of attaching one or more prefabricated metallic panels to the core.

19. The method of claim 18, wherein the at least a portion of the core which is not covered by a metallic panel is covered by a skin portion made of a composite material.

20. The method of claim 18, wherein the step of attaching one or more prefabricated metallic panels to the core includes use of pressure exerted by a fluid to force at least one panel onto the core.

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

forming a shell including at least one metal portion;

Introducing a fluid into said shell;