Fin for surf craft

Abstract

A fin (410) with a discrete structural strand layer (420) that may include high tensile carbon fibre strands (422, 424) and high tensile strength and toughness Kevlar (426) strands. These structural strands may have a tensile strength substantially greater than the other materials typically used in a fin body. The structural strand layer (420) provides an economic and ready technique to vary and control a stiffness characteristic of the fin in a variety of directions or about a variety of axes of rotation; without varying the other common components that may be used in a fin body, for example core (412), layers of fibreglass fabric (414) and / or resin.

Description

BACKGROUND OF THE INVENTION[0001]1. Field of the Invention[0002]The present invention relates to fins and methods for making them as may be applied to surf craft such as surfboards, windsurfers, paddleboards, wave and surf skis, kite-boards, wake boards and the like.[0003]2. Description of the Art[0004]Surf craft (including surfboards) often have one or more fins located on an underside of the surf craft that, for example, may be used for stability, controlling direction and facilitating turning of the surf craft. In addition surfboards may have multiple fins with different functions, for example an uppermost side fin with a curved or airfoil profile may function so as to provide to provide lift when the surfboard is travelling across the face of a wave and the uppermost side fin is located within the face of the wave. It also follows that extra acceleration and drive to the surfboard results.[0005]Fin / s of turning surf craft may experience substantial side ways and other forces to ...

AI Technical Summary

Benefits of technology

The present invention provides a new method for making fins that have better control over their stiffness and physical properties. This allows for the creation of fins with different, controlled stiffness characteristics. This new method also solves the problems of previous methods.

Problems solved by technology

Such manoeuvring of a surfboard places very significant forces on the fins of the surfboard.

Under such forces, the fins tend to experience bending (e.g. between the base and the tip of the fin) and twisting (e.g. between the leading and trailing edges of the fin).

However for typical fins, varying the stiffness characteristics, flexibility or other such properties of the fin in an easily manufacturable and controllable fashion is difficult due to the many layers of reinforcing fabric with impregnating resin matrix contributing to the stiffness or flexibility across the fin.

There is also the additional limitation of what is commercially available in reinforcing fabrics and the strand materials forming them.

None of these prior art fin devices and methods of construction for fins provides an entirely satisfactory solution to the provision of fins for surf craft where the desired stiffness characteristics and other physical properties may be varied in a controllable fashion, nor to the ease of providing a convenient and reliable way of manufacturing fins having different degrees of stiffness or other desirable physical properties.

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