Flex and resonance controlled watercraft

Abstract

A subassembly structurally engineered and manufactured in an aquatic watercraft. The subassembly includes hollow cored or foam filled tube-like structures incased in a foam core blank. The foam core blank containing the subassembly is subsequently to be manually or machined shaped. The invention relates to methods for making the craft produced from subassembly foam blank and surfacing the craft with combinations of curable resins and structural fibers such as fiberglass or carbon, and/or thermoplastics.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS

This patent application claims the benefit of provisional patent APPL NO. 60/642,927 Title: Flex and Resonance Controlled Watercraft, filed by this inventor on Jan. 10, 2005

BACKGROUND OF THE INVENTION

A subassembly structurally engineered and manufactured in an aquatic watercraft. The subassembly includes hollow cored or foam filled tube-like structures incased in a foam core blank. The foam core blank containing the subassembly is subsequently to be manually or machined shaped. The invention relates to methods for making the craft produced from subassembly foam blank and surfacing the craft with combinations of curable resins and structural fibers such as fiberglass or carbon, and/or thermoplastics.

FIELD OF THE INVENTION

The invention relates to the fabrication of wave riding or paddled aquatic boards, and particularly to the use of structural subassemblies incorporated into a surfboard. The method additionally relates to a method for the manufacture of these subassemblies and to a board manufactured using the subassemblies.

Most surfboards presently consist of a foam core that is shaped to produce the desired final shape of the board. Furthermore, in most traditional surfboards (but not all surfboards) have one or more stringers. These typically consist of a vertically oriented strip of wood that runs along the centerline of the longitudinal axis of the board and is exposed on the top and bottom faces of the shaped blank. Other materials, such as dense PVC foam, SphereTex®, micro spheres, and various types of honeycomb are sometimes used in place of wood. The stringer stiffens up the board and the increased rigidity assists in the shaping of the board, as well as contributing to the stiffness of the completed board and the strength of the board.

The surface of this core and the exposed strips of the stringer are then covered by a structural skin. This typically consists of a matrix composed of a structural reinforcement such as fiberglass or carbon fiber and a curable resin such as epoxy or polyester. Alternative skins may consist of wood or other fibrous material, or a thermoplastic.

In related U.S. Pat. No. 6,736,689 a structural subassembly is provided to produce an aquatic gliding board. The subassembly includes a hollow inner shell which is covered with a casing made of foam capable of being machined. The invention also relates to a method of making such a subassembly and to a board made by covering the preceding subassembly with a layer of resin-coated fibers.

There have been a number of efforts at changing the base foam blank for the surfboard industry. The current invention provides the option for the use of engineered composite structures and through their use achieving reproducible flex and strength properties

Virtually all surfboards incorporate one or more fins extending downward from the bottom of the rear area of the board. These may be bonded to the bottom surface, or fin boxes (receptacles to hold and support the base of a fin) may be placed into the foam core prior to the skinning operation.

There are a number of alternative or modified methods of surfboard construction. For example, the foam core may be skinned with some intermediate material, such as a denser foam, before glassing to increase the compressive strength. Alternatively, composite sandwich skins may be molded for the upper and lower portions of the board, and then joined at their perimeter. In another alternative, a mold and an inflatable bladder may be used in combination with composite sandwich construction methods to form the complete board in a single step. These latter two methods result in a hollow board.

The construction method, the type of materials used, and the specific design details (e.g. type, weight, and weave of fibrous reinforcing material, type of resin, type and density of foam, stringer width and composition, etc.), when combined with the physical dimensions of the board, determine its weight, flexural properties, and strength in the presence of various types of loadings.

The experienced surfer develops preferences for certain characteristics in his boards. In general, these preferences will be related to his skill level, his physical characteristics, and the type and size waves he wishes to surf with the board. The hydrodynamic design of the board is one variable affecting these characteristics, other variables include the weight of the board, its moment of inertia (particularly about the yaw axis), the flexural characteristics of the board, and its durability. In general, a change in any one of these properties (e.g. due to dimensional changes, compositional changes, or construction method) will simultaneously change many of the board's characteristics.

Current surfboard construction techniques tend to strongly couple these board characteristics together. For example, increasing the strength against breakage typically increases the weight of the board and the moment of inertia, and reduces flexibility. The usual consequence for most types of waves is a reduction in maneuverability and a reduction in flotation. On occasion, all of these factors come together to produce a board that meets or exceeds the rider's preference desires and expectations. But these boards, frequently referred to as “magic” boards, are rare and, given typical manufacturing tolerances, difficult or nearly impossible to reproduce.

BRIEF SUMMARY OF THE INVENTION

An objective of this invention is to incorporate one or more subassemblies into the construction of a surfboard which will provide the surfboard designer and builder more degrees of freedom in the design and construction so as to assist him in manufacturing a board that can better match the board characteristics with the rider's preferences. The flexural properties include not only the degree of flex as a function of loading, but also the temporal response of the flexed system to intermittent loading and unloading by the surfer and the hydrodynamic pressures on the surface of the board. For example, flexural response can be expected to be most rapid and require the least effort when the frequency of loading and unloading by the rider matches the natural frequency of that mode of vibration of the board (i.e. the loading and response are in, or close to, resonance). Flexural motions affect not only the “feel” of the board, but also its hydrodynamic performance and, in some instances, the structural strength (e.g. structural failure due to buckling). Controlled flexural movements can also provide new hydrodynamic means of controlling the board and increasing its performance, such as the addition of hydrofoils.

The predominant method for manufacturing surfboards is using molded polyurethane foam blanks. The foam blank is generally molded and then structurally reinforced with a wood stringer that is glued into the foam along the centerline of the blank. This wood stringer is installed for a number of reasons that include structural reinforcement and rocker or longitudinal curvature correction. The foam blank is molded to the approximate size required for the finish or custom shape dimensional requirements. The remaining removal and shaping and sanding are then completed by either a computer controlled shaping machine and/or by the individual. An outside covering lamination of a curable resin combined with fiberglass is then applied, sanded, and reapplied to produce a structurally and exterior visually acceptable product.

Alternatively a foam core like polystyrene can be used and can alternatively be covered with higher density foam and either covered with fiberglass and a curable resin or a combination of epoxy resins and fiberglass and/or plastic outer covers.

A number of construction methods are now being used to manufacture hollow boards. Composite foam sandwich or honeycomb core skin methods are combined with a mold and an internal pressure bladder to form, and cure top and bottom sections combined together to produce the shaped board. An alternative product combines pre-formed and cured sections that are then combined in a perimeter assembling ring mold for joining, sealing and finishing of the final board.

A molded surfboard can be manufactured in a variety of ways. One manufacturing method is to form combinations of one or more materials such as plastics or composites such as fiberglass, carbon fiber, Kevlar, micro sphere materials such as Sphere-a-tex, Nomex® honeycomb, aluminum honeycomb, foams cores and sheets made from polyurethanes and polystyrenes and foam or materials chemistries. This construction method can form laminates consisting of an outer skin and a center core with an inner skin to create a three dimensional structural laminate that forms the top and bottom surface of the craft. Alternatively boards can be molded by placing an uncured polymer resinous gel coating material on a preformed mold cavity and then placing on top of the gel coat an uncured polymeric resinous saturated substrate fibrous layer, and then onto the previous layers a resinous saturated substrate fibrous three dimensional layer. This muti-layer composite can then be cured under pressure employing a process such as vacuum bagging. Other molded craft construction methods include solid polystyrene foam cores with outer layers and or laminates of plastics and or composites such as those listed above.

These molding construction methods can incorporate some stringer or reinforcement elements inside the boards.

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS

The invention will be better understood from the description that follows, with reference to the drawings, in which:

FIG. 1 is a top view of a structural flex member and attached fin receiving boxes;

FIG. 2 is a side view of a structural flex member and attached fin receiving boxes;

FIG. 3 is a bottom view of a structural flex member and attached fin receiving boxes;

FIG. 4 is a side view of a core blank containing view line A-A;

FIG. 5 shows a cross-sectional view of the blank containing the structural subassembly thru the section line a-a in FIG. 4 according to an embodiment of the invention;

FIG. 6 shows a cross-sectional view of the blank containing the structural subassembly thru the section line a-a in FIG. 4 according to an embodiment of the invention;

FIG. 7 shows a top view illustrating view line c-c of the sheet subassembly according to an embodiment of the invention,

FIG. 8 shows a cross-sectional view of the sheet subassembly according to an embodiment of the invention, with a main tube structure for flex controlling and structurally reinforcing the subassembly beneath the feet of the user and the forward and rear curve forming panels;

FIG. 9 is a side view of a molded foam blank and may include the subassembly of FIGS. 1,2,3,5,6 and 8 showing the subassemblies that can be incorporated into the molded blank in FIG. 9 and may include the curve forming elements shown in FIG. 8;

DETAILED DESCRIPTION OF THE INVENTION

FIGS. 4 thru 9 depict a surfboard, in a known shape and configuration with a elongated board shape and center portion as shown in FIG. 4 and FIG. 7, a tapered and curved turned up front and rear portion 7, and a slightly turned ends with a reduced width and thickness. As shown in FIG. 9, the board is made of a of a rough shape foam blank, typically a polyurethane molded foam with a density of 2 thru 3.5 pound per square foot, which is finish shaped and then coated or skinned with a generally continuous layer or layers of resin-coated fibers. The foam blank can be made in a mold forming the general shapes incorporating the length, width, thickness and overall curves. This process limits available lengths, widths, shapes and curves due to the need for a new and different mold for every size and shape requirement. FIGS. 6 and 8 show cross sections A-A and B-B of the extruded sheet blank having been manufactured as part of this invention with the selected size, shape and overall rocker curve required. The blank is selected by the shaper, with the general rough size, shape, and curve required for the finished shape requirements either by hand or by machine. This invention provides the manufacturing that converts a flat extruded sheet into a specific specification blank without the use of a mold. The flat sheet may be extruded or non-extruded and may be constructed from a variety of materials that can include polystyrene, polyurethane as well as a variety of hybrid polymers and or materials. The blank is then finished shaped and the receiving fin boxes may be routed into the foam. The blank is then glassed or covered with a fiberglass skin. This increases the mechanical and therefore the durability properties by combining the outer skin with the foam core. According to the invention, the subassembly is formed by one or more internal structural flex members as shown in FIGS. 1, 2, and 3 in various forms such as 2.2 shows side mounted tubes connecting the side receiving fin boxes 5 to the center box 1 and main members 4 and 3 with 11 showing the bottom of the main members and 12 showing the top. 4 shows a rectangular main member that can have a number of internal materials in combinations such as foam, honeycomb, foam filled honeycomb and other structural and or flex controlling materials. These complete structures containing 2, 3 and 4 are shown in association with a wood stringer 10 in FIG. 5 and without a wood main stinger in FIG. 8 as 3 and 14. 14 shows a receiving part for the main tube 3 and the side tubes connecting with the curve forming 7. As defined and incorporated and claimed in this invention, the sheet foam blank 9 may be extruded and is initially a flat sheet with top surface 8 and bottom surface 6. Sheet foam 9 is then prepared for the individual curve or rocker that is manufactured by removing of excess foam from the nose and tail of the sheet and fixing the required rocker curve into the extruded foam sheet with the insertion and affixing of the rocker or curve creating panels 7 into the sheet foam forming the finished blank subassembly as shown in FIG. 8. FIG. 8 shows the sheet blank core 9, with top 8 and bottom 6 with the main tube 3 or panel 4 embedded into the foam core in a cross sectional view. This subassembly of the flex members and rockered foam blank, without the final covering of the blank can be termed a foam blank subassembly for the subsequent production of a watercraft board.

The benefits of the present invention involves the use of advanced materials coupled with engineered suspension to improve on both the traditional solid foam core and fiberglass construction and the solid core molded and molded hollow boards. This improvement is in both the performance and durability of the surfboard.

In the preferred embodiment of this invention the boards are characterized by an internal carbon composite tube-like structure to respond and support the rider, analogous to the suspension on some pedal driven mountain bikes. The internal composite structure can connect hydrofoils or standard fins to one another and to a central or longitudinal main flex control backbone structure. This combination of fin and central board flex movement controls the main planning area under the rider feet leading to increased control of the foils and the flex movement of the board in both flex speed and degree. The areas of the board most flex controlled are the foils and the areas under the front and back feet of the rider. This area is termed the boards planning area or speed spot. The suspension area under the back and front feet of the rider is designed to serve two main functions. The first is to stabilize and create a torsion stabilizing effect in the connecting or joining of two or more fins. The composite elements connect to the fins attachment areas and to one another for an integrated movement of the fins and the riders back control foot. The second element is the main suspension system, which acts and reacts to rider weight and movement control for maximizing the flexing movements of this area.

In the preferred embodiment of this invention the suspension system is a main longitudinal carbon fiber tube of various shapes including oval, round, square or rectangular or combinations of these shapes. The tubes can incorporate varying carbon and/or fiberglass wall thicknesses, with thinner top and bottom tube wall thicknesses, and/or internal varying wall constructions. In the case of the round tube an internal tapering wall can be incorporated with a thicker wall at the rear and a progressive tapering thinner wall forward. This thicker wall tube area provides the suspension board with an increase or higher loading capabilities and faster movement speeds in the up and down flex properties. The oval tube also can continuously taper in its overall height progressing forward towards the nose of the board. Dimensional changes in the height of the tube moving forward can reduce the suspension effects in the nose of the board. This serves a number of purposes such as a transition zone in the rigidity properties of the tube to reduce the likely hood of the board breaking at the tubes forward termination point. This also serves to reduce the abrupt termination feel of the tube for the rider in the nose area of the board. The reduced tapering forward tube allows the nose of the board to move or flex more resulting in a variety of beneficial factors such as movement in steep turns on the wave face

Additionally, in an optional embodiment of the invention, the composite tube or replacement stringer may be combined with a wood or composite stringer in the nose and tail area of the board. This system can be used as a replacement for the traditional wood stringer system. This composite stringer can be made from epoxy saturated and vacuum bagged micro spheres with additional woven carbon cloth placed in strategically needed reinforced areas. The micro spheres have some wood-like movement properties and they can be shaped and sanded. Unlike wood the stringer micro sphere structure is very uniform in its properties resulting in consistent performance and retention of its flex characteristics over many more flex cycles.

The main suspension tube structure is a concentrated or vertical structure and it is anticipated that more than one main tube can be incorporated and placed in alternative areas such as off center and/or on the edge or rail areas of the board. The vertical nature of the tube structure is the logical development for addressing the loading and flex movements required by the rider and the dynamics of the ocean. While alternative horizontal structures may be possible to develop, they would be a significant departure over the elements defined in this disclosure and are not a part of this invention. In the preferred embodiment of this invention the suspension board is equipped with optional hydrofoil fins connected directly to the suspension system at the fin board interface. The suspension and foil connection tubes intersect and are coupled with the main suspension tube stringer elements. This integration of the system is the structural and control backbone that provides very small but very quick initial and return movements of the wing foil sections. These small but fast wing foil section movements are critical given the magnitude of the lift force that can be generated by the foil, and the lift force sensitivity to the slightest change in the angle of attack. The torsional and side-to-side forces involving the suspension tubes at their attachment points and intersections are substantial. Under the conditions of the combined use of the inventions wing foil sections and the suspension elements. The forces or the magnitude of the lift force that can be generated by the foil thought the slightest change in the angle of attack can create break or produce significant distortions in the traditional board construction materials. These forces may be developed either under the control the rider or may be due to undesired hydrodynamic and rider directional changes. The combination of the inertial and hydrodynamic forces need to transfer through the suspension structure with a minimum loss of energy. At the same time, the flex movements required for the increased thrust need to be preserved. These alterations of the boards flex movements involving the degree and speed of flex thru the installation of the suspension system produces a faster, more lively, more responsive, and more springy board.

The fin connection portion of the suspension system attaches to the fins or to the fin attachment box receivers and in so doing reduces the side-to-side movements of the fins—particularly the side fins. This fin suspension attachment system also provides for some of the up and down fin and board rail movement found in the traditional board construction methods. This translates to the rider as a practical transitional feel or reference point. This stabilizing or controlling of the cross board movement is coupled with optimum flex movements of the front and back foot planning areas through the main carbon tube and stringer system. This provides faster speed in general and particularly from one maneuver to the next maneuver.

Experience shows that an occasional board will have exceptional performance qualities. These boards are commonly referred to as “magic boards”. It is common knowledge that most surfboards manufactured are generally not reproduced with sufficient accuracy to result in the same magic-like performance. The suspension boards can ensure much higher numbers of “magic-like” performance surfboards for the riders.

Most, if not all, other major sports hardware devices have made the technology change from materials, such as wood and other materials to the current state of the art composites. A few examples to have made the change from wood, metal, and fiberglass construction to alloys, carbon graphite and other materials that were considered to be exotics just a few years ago include golf clubs, tennis racquets, skis, mountain bikes, snowboards, windsurfers, kite boards, motorcycles, airplanes and boats of all kinds. This is a consequence of a number of factors but is commonly related to strength to weight and additionally to the flex movement characteristics that improve the performance of these products. Strength to weight ratios that translate to flex resonance, or degree and speed of flex movement, is the main factor producing the dramatic performance increases in these products. The main performance enhancement result is less weight and higher performance in power and control.

The increased speed and control of the motions of the tennis ball, golf ball and baseball are a direct result of the new alloys and composites being used in the construction of their respective striking devices. In the example of a modern composite tennis racquet hitting a tennis ball, the racquet can be moved more quickly from one end of the power stoke to the point at which it strikes the ball. The bending characteristics, or flex resonance, of the racquet as it strikes the ball is much faster in both the movement away as it contacts the ball and also as the racquet flexes back with more stored power to increase the return speed of the ball. This increased flex speed is a consequence of the increased stored power as the racquet flexes out and returns back with the additional power and speed. The increase in power and speed of the racquet hitting the ball translates in higher ball speed and control for the player.

A similar set of principles is at play with the other examples of composite sporting goods devices. The golf club strikes the ball and more energy is transmitted to the ball for reasons similar to that of the tennis racquet. In the example of a mountain bike that incorporates fork and frame suspension features, the rider is capable of significantly increased speed and control in both the uphill and downhill aspects of the sport. The additional speed and power is possible because as the rider goes faster the composite frame and suspension allow the frame to move in ways not thought-of just a few years ago. New virtual pivot point frame technology moves and returns from the movement very quickly without losing the power of the rider. With the new frame and wheel suspension and composite frames moving and returning quickly, the energy is not lost through the frame addition and the tires stay in contact with the ground. New bike suspension keeps the bike and rider more neutral for controlling the power on and off the ground for specific trail conditions. This performance increase has redefined the sport with respect to where and how the bike can now be ridden. The flex or controlled movement is designed into these products to be engineered flex resonance or degree of movement related also to movement speed. This translates into the movement characteristics of the whole device or that portion requiring the performance enhancement by using advanced engineered design and materials.

The suspension board system in the solid foam blank applications is dominantly controlling the speed and degree of flex movement in the board. More accurately the system is controlling these elements in very specific ways and areas of the board. The result is more power and control of the board. To achieve this, carbon tubes attach and stabilize the foil fin attachment points, stabilizing and controlling the movements of the foils. All three of the foil fin attachment points are connected to one another at the center fin attachment point and the main carbon tube is attached to the front of the center fin attachment point. The main carbon stringer system is made up of a main carbon tube connected to either a wood or, alternatively, to a composite and carbon longitudinal stringer. The composite stringer contains strategically laminated carbon inside the stringer, to assist in achieving specific flex control needs. The degree or quantity and speed of the out and back movements of individual parts and areas are controlled, as well as the general boards overall flexing speed and degree of movement. This suspension control results in a faster, more springy, and more responsive board. Even the intermediate surfer can experience these performance improvements. The suspension hardware system is providing the surfer with similar performance enhancements to those achieved in the other modern major sports.

At equal speeds and wetted areas, hydrodynamic forces in the water are about eight hundred times greater than those generated in air. This difference is due to the water's density. When coupled with the rider's mass and momentum, and the wave's speed and slopes, the improved performance on and in this denser medium by using the suspension system is significant.

This suspension board system is controlled with body movements and maneuvers similar to those used by the surfer when riding a conventional board with only a few exceptions. The results can be dramatic depending on the size of the board, the skill of the rider, wave characteristics, and the weather conditions. The suspension structural skeletal makeup, and the control over its own flex movement and the fins flex movement, is very important. The consideration of the smallest movement or change in the control of the suspension's structural elements and subsequent changes in the foils surfaces or angle of attack can create a significant change in the performance of the board and rider.

A suspension board reacts on the wave very much like a state of the art mountain bike reacts on the track or trail. The board loads up or flexes from a combination of the rider's mass down on the board while simultaneously being lifted up by the pressures on the wetted area of the board, and hence through the suspension system. Stated another way, the rider's weight and momentum push down on the board and down the wave's face. The suspension system pushes back against the weight of the rider and the internal suspension first flexes down and then flexes or returns back past its zero point (its original position). It does this with much greater speed then would be possible with the old style construction materials used in either the solid foam or the hollow boards. This in turn allows the rider to start an additional new move sooner and execute it with much greater speed. The suspension system provides the flexing actions necessary to allow the rider to almost constantly pump or un-weight the board on the wave face. This pumping induced weightlessness-like state allows the boards maneuvering response to be more significantly influenced by the flex rather than solely by the board's rail and bottom shapes. Stated another way, the suspension boards are more dominantly controlled by the flexing and springiness of the board and rider.

The suspension system board is for the everyday wave and the everyday surfer. These easily learned flex or spring forces and energies harnessed under the feet of the surfer on the everyday wave conditions are a major advancement in the sport. This creates a very fast, loose and effortless-like feeling that translates into a mid level surfer appearing and feeling to have advanced skills while riding on the wave face.

The suspension carbon system now achieves a level of performance for even the intermediate surfer that parallels the improvements in the mountain bikes pre-frame and fork suspension systems. This is achieved thru the connecting of the foil fin connections or attachment points to the main suspension structure and transferring these same forces to the front foot planning area and continuing up the center of the surfboard. The results are faster, stronger, livelier, and more springy performance in the surfboard. The suspension improvements are maintained over the life expectancy of the board.

The rider's weight is forcing the board down and into the wave; the suspension system is designed to flex lift and spring the rider and boards weight partially up and out of the water or wave. This is a very frictionless-like action and a new experience for the rider. The surfer's mass and momentum is pushing down, and the suspension system is pushing with some resistance force up and against the down forces, creating a neutral or flex lift control state.

The suspension board loads up and flexes in a number of areas. When these forces are engineered and incorporated correctly into the rear foils and main suspension system the result is the foils remain in the water during the highest speeds encountered on larger waves.

The flex movements and speeds required for the up and down board and foil control movements of the board and foils must be exact. During the more extreme maneuvers, the board and rider can be in whole or in part suspended on a foil while on the waves face. In some conditions the board and rider may be in whole or in part suspended in a turn on the fin/foil. During this type of maneuver the internal suspension first flexes down and then flexes or returns back to its original position. It does this cycle of flex with greater speed then would be possible with the traditional board construction materials. This speed of flex movement allows the rider to start an additional new move or to transit from one unweighted move the next unweighted move much faster and with greater speed with a reduced loss of speed and energy.

The modern day surfboard construction materials are the product of technologies that have not changed since their introduction in the early nineteen fifties.

I claim as elements of this invention a Molded, High Performance Self or Wave-propelled Aquatic Device such as a Surfboard and the related manufacturing processes. The installation of the flex and movement engineered internal composite tube-like elements provide a structurally integrated performance and durability enhancing composite inner strength reinforcement. The suspension system provides flex and resonance or controlled movement and speed of movement up and down and side to side. This composite inner tube elements system combines the engineered inner materials with outer surface materials to create an inner suspension or flexural spring control system. The composite inner element system can be constructed with a single element or multiple parts.

I claim as an optional element of the invention the connecting or joining of these composite parts with one another to achieve a controlled movement or cycle and speed of motion for up and down, side to side and the various vectors of the motion that could be found and anticipated in the many movements and motions found in the use of the surfboard on an ocean wave. The benefits of the engineered inner materials combined with the outer surface materials to create an inner suspension or flex and movement suspension control system, are a reduction in the uncontrolled and unwanted deflection and or twisting of portions or the board and fins surfaces results in a loss of speed and control of the craft. An additional advantage and benefit of the invention is increased speed of the craft and of the cycle speed of movement of specific structural elements and or surfaces in the craft during both high speed and or high stress maneuvers.

The device of this invention combines fore and aft and side-to-side areas of controlled movement and stability with repeatable accuracies of bend, flex and reduction of uncontrolled distortion and thereby a reduction of water flow friction or drag and thereby increases speed performance. The inner suspension or flexural control system has a direct benefit to the use of fins and particularly to the use of high force or high lift fins such as employed in hydrofoil fin systems. This invention maximizes the use of higher efficiency, hydrodynamic lift generating fins due to the high multidirectional forces generated with these powerful factors including the foil/fin systems. This can be achieved with this invention by combining the ability to build in the exact structural reinforcement and flexural resonance control while still maintaining complete structural integrity of the craft without over-building the outer surfaces of the craft. This is due to the internal structural element that structurally integrates the forces encountered at the point of the fins and fin attachment points or, optionally, the fin holding boxes. The rider's weight and gravity forces interacting and transmitting from above, combined with the lifting and torsional fin forces coming from below, are controlled and somewhat balanced through the structurally engineered components of this invention. Through the combination of side-to-side and longitudinal placement or installation of the internal member section or sections into a molded surfboard forming an internal structural backbone and rib cage a complete structural and performance system is achieved. This internal strength and flex and movement control system connects the side fin attachment points and/or fin receiver points, or fin box system points, to one another and/or either a single or a multiple of longitudinal tubes, beams and or reinforcements in the outer skin laminate structure either on the surfaces outer or internally in the laminate, or on the inner surface of the outer skin laminate.

In another embodiment of the invention a composite backbone and cross member rib system constructed of carbon, fiberglass and composite tube like structures, is installed into a molded surfboard to create the combination of a fore and aft, and side to side movement control. This flex and movement tube control system can connect the side and back fin attachment points and or fin receiver points or fin box system attachment points to one another and to either a single or multiple longitudinal tubes or beams. These tubes may be encased or laminated into outer polyurethane, polystyrene or other foams, and these laminated or encased foam, tube structures may have a wood or composite stringer attached to the tube and laminated or encased inside or outside the foam and carbon/fiberglass tubes.

In another embodiment of the invention the flex and movement tube control system connects the side and back fin attachment points and or fin receiver points or fin box system attachment points to one another and or either a single or a multiple of longitudinal tubes or beams. The tubes and their attachment points to the fin attachment area can be connected through a series of machined or molded connectors allowing for more movement and/or increased restriction of movement. These tubes or tube like members may be encased or laminated into outer polyurethane, polystyrene or other foams, and these laminated or encased foam, tube structures may have a wood or composite stringer attached to the tube and laminated or encased inside or outside the foam and carbon/fiberglass tubes.

In another embodiment of the invention a backbone and cross member rib system is installed into a molded surfboard to create the combination of a fore and aft and side-to-side to side and up and down movement control or the board. This flex control connects the side and back fin attachment points and/or fin receiver points or fin box system attachment points to one another and/or either a single or multiple longitudinal incorporating progressive with board movement suspension system.

In another embodiment of the invention a backbone and cross member rib system is installed into a molded surfboard to create the combination of a fore and aft, side to side and up and down movement. This flex control connects the side and fin attachment points and or fin receiver points or fin box system attachment points to one another and/or either a single or a multiple of longitudinal members

In another embodiment of the invention a cross member rib system is installed into a molded surfboard to create the combination of a fore and aft and side-to-side torsional flex. This element member control connects the side fins and back attachment points with fin and tube receiver and connection points of the fin box system attachment points to one another.

This structural element control connects the side fin attachment points and or fin receiver points or fin box system points to one another and or either a single or a multiple of longitudinal tubes. Tubes may be installed in either the foam blowing stage or prior to the joining of the two halves by routing the main tube and driving the rear foil fin tubes into the foam. The use of rear only tubes as an option for using the main and rear tubes also exists.

Claims

1. A core blank for the subsequent manufacturing of a personal watercraft board for use in the standing position, said core blank comprising: at least one inner structural flex member; comprising a tube like structure; said tube like structure comprising: at least an upper and lower resin impregnated fibrous layer in the upper and lower areas: the core blank further comprising a foam and or core positioned over and/or around said inner structural flex member, said foam core comprising a foam capable of being formed by the removal of material through planing and/or sanding, of the foams outer and inner material.

2. A core blank according to claim 1, wherein: said structural member comprises an upper, lower and sides comprising resin fibrous impregnated structural materials.

3. A core blank according to claim 1, wherein: said inner structural flex member comprises multiple resin-impregnated fiber layers.

4. A core blank according to claim 1, further comprising: a longitudinally extending structural member within said core blank for further control of the flex and structural properties of said core blank.

5. A blank according to claim 1, wherein: said longitudinally structural member extending is in a central position in or on the core blank.

6. A blank according to claim 1, wherein: said foam core blank comprises thermoformed extruded polystyrene foam.

7. A core blank according to claim 1, wherein: said foam core blank comprises a thermoformed extruded polyurethane foam.

8. A core blank according to claim 1, wherein: said foam core blank comprises a thermoformed molded polystyrene foam.

9. A core blank according to claim 1, wherein: said foam core blank comprises a thermoformed molded polyurethane foam.

10. A core blank according to claim 1, further comprising: one or more structural members comprising honeycombed flexible reinforcement structures.

11. A watercraft board according to claim 1, further comprising: one or more fin and or box receiving assemblies connected to one another.

12. A watercraft board according to claim 1, further comprising: one or more fin box receiving assemblies structurally connected to one another and to the main structural member.

13. A subassembly according to claim 1, further comprising: a plurality of longitudinally structural flex members extending within said core blank.

14. A watercraft board according to claim 1, wherein said inner structural flex member includes a wall having a thickness of 0.1 to 4.0 millimeters.

15. A method of manufacturing a subassembly according to claim 1 for use in a subsequent production of an watercraft board, said method comprising: forming a extruded foam sheet: further comprising machining a foam sheet, said foam sheet having forward and rear areas of reduced thickness and a mid section with a inner structural flex member and forming the forward and rear sections with reinforcing forming members having curving shapes: assembling said curved forming members into said forward and rear sheet areas and attaching them to the inner structural flex member located in the mid section of said sheet so that said sheet forms a upwardly forward and rear ended foam shape suitable for machine shaping into a watercraft subassembly.

16. A method according to claim 1, wherein said assembly of said formed subassembly further comprises covering a portion of at least one of said upper and lower surfaces with an outer layer of thermosetting resin-impregnated fibers.

17. A method according to claim 1, further comprising the manufacturing of a watercraft board from the subassembly described in claim 1. further comprising: the removing of material from said outermost layer of said subassembly; and applying an outer covering at least over said outermost layer of said subassembly.