U.S. patent application number 16/230249 was filed with the patent office on 2019-07-18 for surfboard with adjustable and adaptive bottom contours.
The applicant listed for this patent is Darren MacDonald. Invention is credited to Darren MacDonald.
Application Number | 20190217930 16/230249 |
Document ID | / |
Family ID | 67213239 |
Filed Date | 2019-07-18 |
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United States Patent
Application |
20190217930 |
Kind Code |
A1 |
MacDonald; Darren |
July 18, 2019 |
Surfboard with Adjustable and Adaptive Bottom Contours
Abstract
The surfboard disclosed is a structural assembly of a rigid
component forming at least the deck and rails, and a pliant
component forming at least some portion of the bottom surface,
joined to enclose a hollow volume. By means of a user controlled
pneumatic adjustment to the hollow volume, a plurality of bottom
contour shapes is available to the surfboard.
Inventors: |
MacDonald; Darren; (Pender
Island, CA) |
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Applicant: |
Name |
City |
State |
Country |
Type |
MacDonald; Darren |
Pender Island |
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CA |
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Family ID: |
67213239 |
Appl. No.: |
16/230249 |
Filed: |
December 21, 2018 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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15871038 |
Jan 14, 2018 |
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16230249 |
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62718932 |
Aug 14, 2018 |
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15871038 |
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Current U.S.
Class: |
1/1 |
Current CPC
Class: |
B63B 32/57 20200201;
B63B 32/51 20200201 |
International
Class: |
B63B 35/79 20060101
B63B035/79 |
Claims
1. A surfboard, comprising: a rigid shell, said rigid shell forming
at least a longitudinally extending upper-side deck surface and an
underside of said deck surface, and having a right contiguous rail
profile and a left contiguous rail profile at its perimeter, and; a
pliant skin, said pliant skin forming at least a portion of a
bottom surface of the surfboard, and forming an adaptive bottom
contour shape, and; an impermeable connection, said impermeable
connection joining said rigid shell and said pliant skin to enclose
a hollow volume.
2. The surfboard of claim 1, wherein said pliant skin sustains a
tensional force from spanning said underside between said right
contiguous rail profile and said left contiguous rail profile, and
said rigid shell sustains a compressional force from bearing said
pliant skin.
3. The surfboard of claim 1, further comprising a pneumatic valve,
said pneumatic valve being disposed through said rigid shell or
said pliant skin into said hollow volume, and operating to control
an ingress and an egress of air, thereby adjusting said adaptive
bottom contour shape.
4. The surfboard of claim 1, further comprising a pneumatic valve,
said pneumatic valve being disposed through said rigid shell or
said pliant skin into said hollow volume, and operating to control
an ingress and an egress of air, thereby adjusting said surfboard's
volume.
5. The surfboard of claim 3, further comprising a bottom contour
substructure integral to said rigid shell, said bottom contour
substructure protruding downwardly from said underside through said
hollow volume, and operating to influence said adaptive bottom
contour shape, wherein said impermeable connection is a chemical
bond.
6. The surfboard of claim 3, further comprising a bottom contour
substructure separable from said rigid shell, said bottom contour
substructure protruding downwardly from said under-side through
said hollow volume, and operating to influence said adaptive bottom
contour shape, wherein said impermeable connection is a detachable
mechanical bond.
7. A surfboard, comprising: a rigid shell, said rigid shell forming
at least a longitudinally extending upper-side deck surface and an
inverse under-side of said deck surface, and having a contiguous
rail profile at its perimeter, and; a pliant skin, said pliant skin
forming at least a portion of a bottom surface of the surfboard,
and forming an adaptive bottom contour shape, and; an impermeable
connection, said impermeable connection joining said rigid shell
and said pliant skin to enclose a hollow volume, and; a pneumatic
valve, said pneumatic valve being disposed through said rigid shell
or said pliant skin into said hollow volume, and operating to
control an ingress and an egress of air, thereby adjusting said
adaptive bottom contour shape and the volume dimension of said
surfboard, and; said rigid shell also comprising a bottom contour
substructure protruding downwardly from said under-side through
said hollow volume, and operating to influence said adaptive bottom
contour shape.
8. A process for adjusting surfboard bottom contours to a plurality
of shapes, which comprises the alternative steps of: a) temporarily
unsealing and controlling the ingress of air into a hollow volume
enclosed between a rigid shell that forms at least the deck and
rails of the surfboard, and a pliant skin that forms a portion of
the bottom surface of the surfboard, before resealing the hollow
volume by means of a pneumatic valve disposed through the rigid
shell or said pliant skin, thereby distending the pliant skin away
from the under-side of the deck, producing a convex bottom contour;
or b) temporarily unsealing and controlling the egress of air from
a volume enclosed between a rigid shell that forms at least the
deck and rails of the surfboard, and a pliant skin that forms a
portion of the bottom surface of the surfboard, before resealing
the hollow volume by means of a pneumatic valve disposed through
the rigid shell or said pliant skin, thereby contracting the pliant
skin towards the underside of the deck, producing a concave bottom
contour; or c) temporarily unsealing and facilitating the free
communication of air enclosed between a rigid shell that forms at
least the deck and rails of the surfboard, and a pliant skin that
forms a portion of the bottom surface of the surfboard, with the
surrounding air before resealing the hollow volume by means of a
pneumatic valve disposed through the rigid shell or said pliant
skin, producing a flat bottom contour.
Description
BACKGROUND OF THE INVENTION
Field of the Invention
[0001] This invention relates to surfboards for riding waves, and
recreational watercraft known as knee-boards, body-boards,
windsurf-boards, kite-boards, paddle-boards, stand-up-paddle
boards, and the like. Specifically, this invention relates to
surfboard bottom contours.
Background Art
[0002] A surfboard of the current era is typically shaped to have
bottom contours which facilitate a particular intended
functionality and "feel." Generally, a convex roll enables a
surfboard to sit down in and displace the water of a wave, while
flats or concaves enable a surfboard to lift from and plane upon
it. Combinations of these basic forms and additional variations in
bottom contours such as "vees," panels, bellies, concaves,
channels, steps, chines, and edges, direct water flow and further
influence the ways in which a surfboard will handle.
[0003] Surfboards in the art are typically fabricated as rigid
laminated surfaces over a foam or hollow core. Rigid surfaces
efficiently direct water flow, yet generally delimit the bottom
contours of a surfboard to a fixed shape and range of function.
These rigid surfaces are generally brittle and subject to pressure
dings which can permanently deform bottom contours.
[0004] Surfboards are conventionally measured, along with the
traditional values of length, width, and thickness, as a volume.
The thickness foil dimensions, which typically vary over the length
of a surfboard, contribute to a surfboard's specific volume, and so
to its buoyancy as well as its flexibility. Generally, a thicker
surfboard foil will float more than a thinner one, while a thinner
surfboard foil will flex more than a thicker one. Surfboard shapes
in the art typically compromise the attributes of float and flex. A
specific and fixed volume delimits the range of functionality of a
surfboard.
[0005] It is desirable that an alternative surfboard be available
that is adjustable to a range of bottom contour shapes and volume
dimensions.
BRIEF SUMMARY OF THE INVENTION
[0006] Accordingly, it is the object of this invention to provide a
durable surfboard with bottom contours that are adaptable to a
plurality of different shapes. It is another object of this
invention to provide a surfboard with a functionally variable
volume. The disclosed surfboard is of simple construction, and
achieves these objectives by reliable methods of manufacture.
[0007] The surfboard is a structural assembly of a rigid shell that
forms at least the deck and rails, and a pliant skin that forms at
least some portion of the bottom surface. The skin is stretched to
a degree of tension sufficient to efficiently direct water flow by
spanning remote portions of the shell to which it is connected. A
hollow volume is enclosed between the joined shell and skin. The
sealed surfboard assembly is vent-able and drain-able and
pneumatically adjustable by means of a valve or valves fitted
through the shell. Bottom contour shape and thickness foil is
modifiable by way of pneumatic adjustments that reshape and further
tension the adaptable skin by controlling the extent of its convex
distension away from, or concave contraction towards, the underside
of the deck. The shape of the underside of the shell, operating as
a bottom contour substructure from within the hollow volume of the
surfboard assembly, can further influence the contours of the skin
that spans it.
[0008] One advantage of the disclosed surfboard is that it is
adjustable to a plurality of bottom contour shapes, enabling a
single surfboard to be adjusted for different conditions and user
preference. Another advantage is that its functionally variable
volume increases the surfboard's range of buoyancy, accommodating
different user weights and abilities. Another advantage it that it
it's resilient pliant surface is resistant to pressure dings.
Further, a novel "feel" and functionality is realized with the
surfboard's adaptive bottom contours.
BRIEF DESCRIPTION OF THE DRAWINGS
[0009] In illustrations and embodiments,
[0010] FIG. 1 shows a vertical cross-sectional view from the tail
of an embodiment.
[0011] FIG. 2 shows a perspective view of another embodiment's
shell from the left side of the tail
DETAILED DESCRIPTION OF THE INVENTION
[0012] A surfboard with adjustable and adaptive bottom contours is
here disclosed with reference to drawings of exemplary embodiments.
Surfboard shapes are complex combinations of compounding curves
that all inform one another. Aspects of surfboard design already
known to the art that are applicable to embodiments of the
invention disclosed, such as plan shape, rocker curve, rail shape,
along with their dimensions and proportionality, are not here
described in detail. The illustrations and descriptions throughout
this disclosure, along with any statement of materials or
dimensions, are provided not to limit this disclosure in any way to
these particular embodiments, but are to be interpreted as
encompassing any equivalent, variant, or alternative embodiment,
without departing from the scope of the appended claims.
[0013] FIG. 1 shows an embodiment of the surfboard in a vertical
cross-section at its longitudinal center point, as seen from the
tail, showing its lateral extension from rail to rail. The
surfboard is a structural assembly of a pliant bottom skin 1 joined
by an impermeable connection 2 to a rigid upper shell 3. A hollow
volume 7 is enclosed within the assembly.
[0014] The term "skin," as claimed, refers to the pliant portion of
the surfboard's bottom surface that forms its adaptive bottom
contours. The skin is a resilient and impermeable membrane layer
that spans remote portions of the shell. As such, the sealed nylon
skin of this embodiment is stretched to span the lowermost surfaces
of the shell along its rail profiles 4, which extend from nose to
tail. Tensioned yet elastic, the skin forms the entire bottom
surface of the embodiment and assumes its basic contour shape from
the shell, with which it maintains an impermeable connection 2 at
its peripheries.
[0015] The term "shell," as claimed, refers to any rigid portion of
the surfboard, and forms its basic length, width, and unmodified
thickness foil dimensions. As such, the composite foam and
fiberglass shell of this embodiment extends longitudinally from a
nose to a tail, and laterally from rail to rail, with a domed deck
5 contour and a thinly spaced inversely facing underside 6 contour,
inboard of the left and right contiguous rail profiles 4. The rail
profiles extend downwardly from the deck's peripheries, forming the
surfboard's plan shape with their laterally oriented surfaces and
the surfboard's rail rocker curve with their lowermost surfaces.
The inboard sections of the rail profiles return upwards into the
hollow volume and blend into the underside of the shell. Joined as
an integral and impermeable structure, the skin and shell together
form the exterior surfaces of the surfboard and enclose a hollow
volume.
[0016] The term "hollow volume," as claimed, refers to the sealed
air space enclosed between skin and shell that is capable of being
positively, negatively, or equally pressurized in relation to the
atmospheric pressure surrounding the surfboard. As such, the hollow
volume of this embodiment is accessible by a two-way pneumatic
valve 8 fitted through the shell, through which ingress or egress
and sealing of air within the surfboard can be controlled.
[0017] The pneumatic valve 8 enables the user to adjust the bottom
contour shape of the surfboard. By controlling an ingress of air
through the valve and positively pressurizing the hollow volume, an
incrementally adjustable convex bottom contour 10 is produced as
the skin is distended outwardly. Alternatively, by controlling an
egress of air through the valve and negatively pressurizing the
hollow volume, an incrementally adjustable concave bottom contour
11 is produced as the skin is contracted inwardly. The valve can be
closed at any point within the range of skin travel to maintain any
extent of pneumatically modified bottom contour. These
modifications also adjust the thickness foil and buoyancy of the
surfboard by increasing or decreasing its volume.
[0018] A flat bottom contour 9 is produced by venting the hollow
volume 7 to enable an equalization of internal air pressure with
that of atmospheric. This is achieved by way of a dedicated vent
aperture also installed through the shell, or via the pneumatic
valve 8 itself. Resealed as such, the stretched skin is at its
least taut and most disposed to a dynamic adaptive contouring when
in use. The skin will temporarily recoil from and rebound to its
flat bottom contour when subject to the loading forces of water. As
the skin flexes and directs water flow over its contours, its
pliancy damps water surface chop and vibration, smoothening the
"feel" of the user's ride. The skin's adaptive contouring also
provides a directional stability to the surfboard. As the skin is
temporarily forced into closer contact with the underside of the
shell, the surfboard's inboard thickness foil is thinned, and
inboard sections of the shell's rail profiles further shape its
contours and direct water flow.
[0019] The skin is adjustable and adaptive, yielding to both air
pressure within the surfboard, and to hydrodynamic forces from its
environment in use. The dynamic adaptability of bottom contours is
incrementally less pronounced as the skin is adjusted by the user
by positively or negatively pressurizing the hollow volume. The
greater the convexity or the greater concavity of the adjusted
bottom contours, the greater the tautness of the skin. A taut skin
will operate to direct water flow over the convexly or concavely
adjusted bottom contours, functioning to displace water, or plane
upon it, respectively. The skin is resilient, rebounding to its
adjusted contour after a more significant point load such as that
of an impact, and is resistant to lasting deformations such as
creases and pressure dings. The surfboard assembly is durable and
lightweight. The surfboard's hollow volume is able to be vented and
drained.
[0020] FIG. 2 shows a perspective view of another embodiment's
shell exploded from its skin, and with the inclusion of a centrally
positioned bottom contour substructure 14. The shell's upper-side
deck 5 and thinly spaced inverse underside 6 extend in a
longitudinal curvature from a nose 17 to a tail 18, and laterally
between left and right rail profiles 4, in domed and concave
contours respectively.
[0021] The term "substructure," as claimed, refers to any shape or
component of the rigid shell's underside that functions to
influence the bottom contour shape of the pliant skin from within
the hollow volume of the surfboard. As such, the substructure of
this embodiment is a single protrusion from the shell's underside 6
running longitudinally straight from nose to tail at the lateral
center of the shell. Protruding downwardly to extend lower than the
perimeter rail profiles that form the embodiment's rail rocker
curves, the substructure delineates a central rocker curve with its
lowermost surfaces.
[0022] Stretched to the shell, the skin will span between the
shell's lowermost surfaces along its rail profiles 4 to which it is
joined, and contact the lowermost surfaces of the central
substructure 14 along its length. So assembled, the bottom contour
of the surfboard is a continuous panel "vee" 21 when the enclosed
air pressure is equalized with that of atmospheric, as indicated by
the broken line in FIG. 2. A two-way pneumatic valve 8 is fitted
through the deck, and the air enclosed on both sides of the central
substructure is able to communicate freely by way of a laterally
fitted open passageway 19. The user controlled ingress of air into
the hollow volume will distend the skin and produce a convexly
rolled bottom contour. The user controlled egress of air from the
hollow volume will contract the skin towards the shell and produce
a double concave "vee" bottom contour. Any adaptive bottom
re-contouring in the use of this embodiment will be of a lesser
magnitude to that of the embodiment shown in FIG. 1 (the plan shape
length and width, and materials of the two embodiments being
otherwise equivalent), as the skin spans a smaller unrestricted
surface area in its lateral orientation.
[0023] Another exemplary embodiment has a similar longitudinally
central substructure that protrudes downwardly from the deck's
underside, yet remains above the bottom surface of the rail
profiles in the surfboard's nose and forward section, and tapers to
protrude lower than the rail profiles only through the aft and tail
section. In this embodiment, the skin is joined to the shell only
at the rails, and is not adhered to the surfaces of the
substructure it contacts. The bottom contour produced when the
hollow volume is equal in pressure to that of atmospheric, is a
flat panel forward blending to a panel "vee" aft. When the skin is
distended by the controlled ingress of air, a "belly" forward
blends to a rolled "vee" aft. When the skin is contracted by the
controlled egress of air, a single concave forward blends to a
double concave bottom contour aft.
[0024] Referring now to both FIG. 1 and FIG. 2 at once, outboard
left-side position 12, inboard left-side position 13, inboard
right-side position 15, and outboard right-side position 16, are
each location markers for other alternative bottom contour
substructure formations protruding from a shell's underside in
other embodiments. Illustrated by indicating arrows, their vertical
orientations are depicted in FIG. 1, while their longitudinal
orientations are depicted in FIG. 2. An embodiment with
substructure formations at outboard left-side position 12 and
outboard right-side position 16 that protrude lower than, and
delineate a similar rocker curve to the shell's rail profiles, has
chine bottom contours. An embodiment with substructure formations
at inboard left-side position 13 and inboard right-side position 15
that protrude to the same depth as its rail profiles, will have a
triple concave bottom contour when the skin is pneumatically
contracted.
[0025] Various alternatives of substructure layouts at these
locations, which produce alternative bottom contour shapes, are
possible in other embodiments. Bottom contour substructure
formations: extend the complete longitudinal length from nose to
tail of the surfboard, or only a portion thereof; protrude below,
to the same depth as, or above the lowermost surfaces of the
shell's rail profiles; delineate a similar rocker curve to the rail
profiles, or a divergent one; are fitted with passageways that
allow the communication of air between them, or function without
them; are aligned straight from nose to tail, in a parabolic manner
to follow the surfboard's template curve, or to curve outwardly
towards the surfboard's rails. In consort with the skin's range of
pneumatic modification, various combinations of blended bottom
contours such as "vees," panels, "bellies," concaves, channels,
steps, chines, and edges are possible alternatives in such
embodiments. Other embodiments include alternative substructure
formations contacting the skin at other positions between outboard
left-side position 12, inboard left-side position 13, inboard
right-side position 15, and outboard right-side position 16,
influencing alternative bottom contour shapes.
[0026] Possible alternative shell and substructure formations are
many and are customizable in fabrication, and along with the
possible alternative material properties of the connected skin,
affect the function and "feel" of the complete structural assembly
that comprises all embodiments of the surfboard.
[0027] In all embodiments, the shell forms all rigid portions of
the surfboard, and at least the deck and plan shape of the
surfboard assembly. It extends longitudinally from a nose to a
tail, and laterally from rail to rail, with a flat or domed or
concave deck contour. In different embodiments, the shell's plan
shape can be that of any long or short, traditional or alternative,
conventional or side-cut, pulled or full, outline; and include any
nose and tail shape. The shell's rail profiles left and right,
extending out from the deck and curving downwardly to delineate
some amount of rail-rocker curve along their lowermost edges and
forming a thickness foil along the shell's lateral peripheries, can
be hard or soft, pinched or full, with or without a release edge,
and/or tucked or chine, or some combination thereof, in shape. The
inboard shape of the rail profiles, which extend back upwardly
towards the shell's underside within the hollow volume, can also be
any combination of soft or hard shape, rounded or with an edge. The
deck and its underside surfaces tend to follow a similar, though
inversely shaped, lateral contour, and are thinly spaced from one
another. The shell is rigidly unyielding and inflexible under
localized point load, and yet is flexible when subject to larger
loading forces from the user and the water, in that it has stiffly
rebounding flexural and torsional properties, and will spring back
to its fabricated shape when released from these forces in use.
[0028] The shell, along with the bottom contour substructure, is
fabricated from any sufficiently rigid material with an adequate
strength-to-weight ratio, compressive strength, and flexural
characteristic. Shells are comprised of a shaped or built core,
over which a sufficiently flexible and durable, corrosion and
ultraviolet resistant material is laminated. Embodiments that are
reductively shaped from blanks comprise core materials such as wood
or polyurethane or expanded polystyrene foam or other material
capable of being shaped. Glass fiber fabric or carbon fiber or
other cloth permeated with a polyester or epoxy resin, is laminated
to form the composite sealing structure of the shell's outer layer.
In other embodiments, cloth and thermosetting resins are laminated
to form the entire shell, or its inboard portions, without the use
of another core material. Embodiments that are built additively
from component parts also include materials such as wood or foam,
as well as molded polymers or aluminum alloys. Methods of
fabrication of the shell include shaping by hand or machine,
computer numerical control routing, injection molding, 3D extrusion
printing technologies, or other form of manufacture.
[0029] The principle function of a shell's substructure is that it
operates to influence the shape of the skin from within the hollow
volume, producing directionally oriented or otherwise curved
formations of bottom contours at some stage of the surfboard's
pneumatic adjustment or skin adaptation in use. Alternative bottom
contour substructures also operate to: inform thickness foil
profiles and dimensions inboard of the rail profiles; affect the
flexural characteristics of the shell; restrict portions of the
hollow volume accessible to a pneumatic valve at some stage of the
skin's adjustment; and to limit the unrestricted surface area of
the skin. Substructure formations may be fabricated as integral to
the shell as part of a unified shaped construction; or be removable
from it as a framework of interchangeable spars, ribs, and
stringers that influence divergent bottom contour shapes in a
removable and interchangeable skin.
[0030] The term "impermeable connection," as claimed, refers to the
waterproof and airtight bonding of the shell and the skin. This
connection is at any point on the shell, and at the lateral
peripheries of the skin. In some embodiments, the connection is a
permanent chemical bond, such as epoxy or polyester resin,
polyurethane or other adhesive. In other embodiments, the
connection is a detachable mechanical bond, such as a continuous
aluminum molding that clamps the skin to a mating surface on the
shell by means of friction and set screw assemblies, or by lacing
and cinching, or the like.
[0031] The hollow volume sealed between the connected shell and
skin is quantifiably adjustable by means of a pneumatic valve
through which the user controls the ingress or egress of air into
the surfboard. The valve is comprised of any material assembly
suitable for a marine environment that is capable of sealing air of
sufficient positive or negative pressure in relation to the
surfboard's surrounding atmospheric pressure. In some embodiments,
the valve is a metal assembly, such as brass or stainless steel or
aluminum. In other embodiments, the valve is a plastic assembly,
such as nylon or polyvinyl chloride or other polymer. In some
embodiments, the valve is operated orally; in other embodiments,
the valve is operated via a separate air compressor or pump; in
other embodiments, a hand operated diaphragm pump is part of the
valve assembly itself. In some embodiments, pneumatic adjustments
are made by the user as the surfboard is in use in the water; in
other embodiments, pneumatic adjustments are made by the user on
shore. Some embodiments include an additional venting valve
aperture and drain plug fitted through the shell, enabling the user
to control the free communication of fluids between the hollow
volume and the air surrounding the surfboard.
[0032] The skin spans remote parts of the shell to which it is
connected, and forms at least some portion of the surfboard's
bottom surface and all of the bottom contours that are adjustable
and adaptive. The skin is comprised of any sufficiently pliant
material able to form smoothly to compound curves, having adequate
tensile strength, weight, durability, abrasion resistance,
elasticity, and impermeability or the capacity to be sealed. In
some embodiments, the skin is fabricated from isotropic fabric of
synthetic woven fiber, such as nylon or polyester; or organic woven
fiber, such as canvas or flax; or the like. In other embodiments,
the skin is fabricated from anisotropic fabric, for its
directionally oriented elasticity characteristics. The fabric skin
is made sufficiently water resistant and airtight with a flexible
and durable, corrosion and ultraviolet resistant sealant or
coating, such as urethane or latex or varnish or wax and oil blend,
or like material. The sealed skin surface is smooth and durable. In
other embodiments, the skin is fabricated from impermeable plastic
film, rubber membrane, neoprene, sailcloth, or the like.
Alternative materials and methods of skin fabrication produce
different magnitudes of skin elasticity and adjustability in
different embodiments.
[0033] It is the complete structural assembly of skin and shell
that comprises embodiments of the surfboard, and their alternative
methods of structural correlation also affect the function and
"feel" of the surfboard. In some embodiments, the skin is connected
to the shell with some slack; in other embodiments, the skin is
stretched taut to the shell; in other embodiments, the skin is heat
shrunk to the shell.
[0034] In the embodiment depicted in FIG. 1, the pliant skin and
rigid shell respectively sustain a dynamic tension--compression
structural correlation in their assembly. The skin is tensioned to
exert rail-to-rail compressive forces on the shell to which it is
connected, serving to flex and reinforce the domed deck contour;
and the laterally compressed shell maintains an active tensile
stress in the skin, serving to reinforce the resilience of the flat
bottom contour formed when the hollow volume is of equal pressure
with atmospheric. User weight and movement is transferred through
the engaged shell to further dynamically tension the skin as the
user flexes the deck. As the bottom contours are pneumatically
modified convexly or concavely by the user, the degree of
compression in the shell and the tautness that the tensioned skin
retains from its counteracting forces, is altered by the hollow
volume's state of positive or negative air pressure which itself
reinforces the tautness of the skin.
[0035] Overall dimensions differ significantly between embodiments,
depending on the type and intended use of the surfboard, ranging
generally from 3' to 12' in length, 18'' to 30'' in width, and
3/4'' to 4'' in basic unmodified thickness. Thickness dimension
varies with the pneumatic adjustments of specific embodiments as
well, and its scope is determined by the span of the skin both
laterally and longitudinally, and its material elasticity. The
range of skin travel when adjusted from maximum distension to
maximum contraction is generally not more than four inches in any
one embodiment, but is typically closer to one inch at maximum.
Skin thickness, including any sealant, varies from about 1/32'' to
3/16''. The downward protrusion of the rail profiles and
substructure formations from the shell's deck and underside
typically ranges from 3/4'' to 4''. The thickness of the shell
between its deck and its underside, inboard of the rail profiles
and from which the bottom contour substructure protrudes, typically
ranges from 1/8'' to 3/4''.
[0036] In the embodiment depicted in FIG. 2, a single fin box 20 is
installed in the central substructure 14. The skin is adhesively
joined to the proximate bottom surfaces of the substructure that
house the fin box, and is cut away to enable the installation of a
removable fin through it and into the fin box. Other embodiments
are single fin or twin fin or other multi fin setups with fin boxes
or like fin mounting systems installed into substructure formations
through the skin, or into portions of the shell's underside that
the skin does not span. Other embodiments have non-removable
"glass-on" fins that are affixed to the skin or portions of the
shell's underside that the skin does not span.
[0037] Other embodiments of the surfboard are finless, the adaptive
bottom contours providing an alternative means for directional
control. As the resilient skin yields to hydrodynamic forces
beneath it, in consort with the rail profile shapes it contacts, it
provides a directional stability to the surfboard. The skin is also
responsive to the user weighting and flexing the deck above, which
in some embodiments push substructure formations against the skin
to reinforce and accentuate directionally oriented bottom contours
that are sufficient for controlling the surfboard without a
fin.
* * * * *