Surfboard fin having a rearwardly offset bearing surface

Abstract

A fin for a surfboard, having a main body which comprises a first edge which is in contact with the board when the fin is secured to the board, a leading edge at the front and a trailing edge at the rear, a rear curve connecting the leading edge and the trailing edge, the trailing edge comprising a forwardmost front tip. The main body is extended rearwards by an arm which extends from a straight line which is perpendicular to the first edge and passes through the front tip of the trailing edge, as far as the rear curve, the arm having a length greater than approximately 8 cm.

Description

CROSS-REFERENCES TO RELATED APPLICATIONS[0001]This application claims the benefit of the U.S. Provisional Application No. 62 / 045,799, filed on Sep. 4, 2014, the entire disclosures of which are incorporated herein by way of reference.BACKGROUND OF THE INVENTION[0002]The present invention relates to a fin for a surfboard, as well as to a surfboard having such a fin.[0003]Surfboards generally comprise, towards the rear of the board, one or more fins arranged in vertical planes, comprising, starting from the front, a leading edge forming a convex curve which, as it descends, is inclined rearwards, and then a lower edge substantially forming a tip, and, rising again at the rear, the trailing edge, generally with a concave curve.[0004]The fins constitute vertical planes which, in the longitudinal direction, cut through the water well to reduce drag and braking of the board and, in the lateral direction, offer high resistance, limiting transverse movement.[0005]The surfer can thus control ...

AI Technical Summary

Benefits of technology

[0022]According to the invention, the rear part of the arm forms a bearing surface which is spaced apart from the main body of the fin, which makes it possible to obtain maximum bending between the rear part of the arm and the main body of the fin, which is connected to the board and which is not very flexible. The fin according to the invention provides, when coming out of a turn, a propulsion and acceleration effect. It is possible to modulate the bending of the arm by adjusting the length of the arm, the dimensions, the geometry and the shapes of the bearing surface(s) located at the rear of the arm. According to another advantage, the fin according to the invention makes it possible, owing to the speed and the inclination of the board induced by the surfer in the trajectory, to generate lateral twisting of the arm up to the rear end thereof, along an axis perpendicular to the first edge and passing through the plane of the main body (i.e., perpendicular to the board), which increases control during the turn and which restores propulsion at the end of the trajectory when the surfer releases his weight.

[0023]Advantageously, the arm comprises a height reduction, the arm comprising at the rear of the height reduction a bearing surface with a height greater than the height reduction. This feature enhances flexibility.

[0026]According to this feature, the bearing surface still performs the function of limiting the lateral drift of the board even when it is well out of the water, for example in jumps. Furthermore, this rear part separated from the board also makes it possible to chase the power of the swell at depth. According to this configuration, the rear part of the arm is positioned outside the turbulence which occurs at the surface or along the board.

[0029]Tests have shown that, as wings secured to the rear end of an arm have a degree of lateral flexibility, a dynamic reaction of these wings is obtained, which can give the board propulsion at the end of a turn in small waves. It also provides better control of the trajectory in medium or strong waves, which provides greater reassurance for the surfer by virtue of the increases in speed provided by the fin.

[0034]Advantageously, the horizontal rectangle starting from the perpendicular line drawn at the rear end of the upper edge, in which the arm and the wings fit, has a length to width ratio of greater than approximately 2. This configuration makes it possible to enhance the dynamic effect of the fin.

[0037]The fin may comprise two wings arranged symmetrically with respect to the plane of the main body of the fin. This ensures a degree of resistance of the fin to vertical movements.

Problems solved by technology

The fins known in the prior art are relatively compact assemblies with little lateral flexibility, which tends to limit under all circumstances the lateral drift of the rear part of the board.

However, this rear tip 34 directly attached to the main body 12 has a high rigidity in terms of lateral bending, such that the dynamic properties of the fin are quite poor.

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