Sandwich Construction Fin Mounting

Abstract

Fin plug assemblies for mounting a removable watercraft fin are disclosed. In some embodiments the fin plug assemblies include a fin plug and a mounting insert, wherein the fin plug is configured to mount removable fins (e.g., surfboard fins) to a surface of a watercraft. In some embodiments, the mounting insert has a laminar or sandwich construction. Methods of manufacturing the fin plug assemblies and watercraft including the fin pug assemblies are also described.

Description

FIELD OF THE INVENTION[0001]This invention relates to watercraft and in particular to assemblies for removably securing fins to the watercraft.BACKGROUND TO THE INVENTION[0002]A number of watercraft make use of fins that project from the water-facing surface of the craft. On planing craft, such as surfboards, the fins are typically foil-shaped to enhance the directional stability of the craft during high speed planing motion and to facilitate turning.[0003]The invention will be described with reference to surfboards as examples of watercraft, but it will be appreciated that the invention will find application in any watercraft that makes use of removable, replaceable fins that are mounted in a fin mounting assembly secured within a cavity formed in the water-facing surface of the craft.[0004]On watercraft such as surfboards the use of removable fins has become quite commonplace. These fins are removably and interchangeably fitted to the watercraft by means of fin mounting systems em...

AI Technical Summary

Benefits of technology

The invention is a fin plug assembly for removably mounting a watercraft fin on a water-facing surface of a watercraft. The assembly includes a fin plug and a mounting insert. The mounting insert has a cavity that matches the shape of the fin plug and is shaped to fit snugly on the watercraft. The mounting insert is made up of layers with different material characteristics. The laminar construction of the mounting insert can be achieved by using a foam body with a structural core or by using a high-density foam with a rigid laminate on the water-facing surface and a load-dissipating laminate on the inwardly facing surface. The fin plug is made of polycarbonate and the mounting insert is made of layers. The mounting insert has a flange plate that is designed to accommodate the fin plug and allows for rotation of the fin plug within the flange plate. The technical effects of this invention include improved stability and secure mounting of the watercraft fin on the watercraft, as well as reduced impact and load on the fin during use.

Problems solved by technology

One of the problems encountered with known fin plugs arises from the characteristics of surfboard construction.

In typical installations, the outer laminate of the surfboard is extended partially over the fin plug, but given the size limitations imposed by the locations where the fin plugs are installed on the surfboard, the laminate contact surface offered by the fin plug is generally insufficient to provide any real support to the fin plug in resisting the torsional loads imposed on the fin plug.

However, the low-density foam of the core generally does not have sufficient strength to resist the torsional fin plug loads without deformation or weakening of the surrounding foam over time, with consequential reduction in performance of the fin, cracking and shattering of the laminate in the vicinity of the fin plug and eventually delamination of the laminate from the core.

These fin plugs are typically of injection mouldable plastics, which generally does not bond well to the polyester resin most commonly used to laminate modern watercraft, unless the fin plug is treated, for instance by sanding, to provide some form of mechanical key and even this does little to improve bonding of the plastic to the resin.

In addition, it will be appreciated that this introduces a secondary process that increases the cost and complexity of fin system installation.

Images