FR2543100A1 - Fin, rudder or keel - Google Patents

Abstract

The fin, rudder or keel for use with wave or water craft comprises a pair of sides (18), a leading edge (14), a trailing edge (16) and a tip (22). Each side of the fin (10) is formed with two or more longitudinally extending ridges (26) extending between the leading edge and the trailing edge and separated by a channel (28).- The ridges and the channel between them have a scalloped shape so that there is a continuous transversely extending curve between the top of one ridge and the top of an adjacent ridge. In one embodiment, the region of the trailing edge of the fin corresp. to a channel, adjacent the tip of the fin, is extended rearwardly compared to the trailing edge corresp. to a channel remote from the fin.

Description

DERIVATIVE, GOVERNOR OR Keel
The present invention relates to daggerboards, rudders and keels of the type used for surfing sleeves, water skis, all kinds of surfboards, windsurfers, yachts and other similar nautical devices. Although the present invention applies generally to daggerboards, rudders and keels, it will be described below with particular reference to daggerboards.

Conventional drifts of the known type have ordinary hydrodynamic planes capable of crossing a liquid at rest with a relatively small drag. However, in practice, the drifts rarely cross bodies of water at rest. It is more common for water to be in motion and / or to exert pressure on the fin. In these cases, the efficiency of conventional leads is significantly reduced. This results from the fact that the principle of the conventional drift does not include any device forcing the water to flow in a desired direction, for example longitudinally or from front to back.

In the absence of such devices, the water tends to detach along the leading edge of the fin and finally detaches from the tip of the fin. This creates drag and causes a general loss of steering control. In addition, conventional centreboards do not include devices to take advantage of the potential torque near the tip of the centerboard, so as to improve propulsion and control.

The present invention comprises, in one of its forms, a fin for nautical craft, which comprises a pair of lateral faces, a leading edge, a trailing edge and a point, each face of the fin consisting of at least two edges arranged longitudinally from said leading edge to said trailing edge, and separated by grooves, the edges and the grooves located between them having a scalloped shape, so as to obtain a continuous curve s 'extending transversely on the drift between the top of a first edge and the top of a second adjacent edge.

According to another form of the present invention, there is provided a fin intended for nautical craft, which comprises a pair of lateral faces, a leading edge, a trailing edge and a point where the faces of the fin consist of at least two edges arranged longitudinally and separated by at least two grooves, and the area of the trailing edge of the fin corresponding to at least one groove near the tip of the fin extending rearward, so as to correspond to at least one groove away from the fin.

Preferably, the elongated part of the fin is at least 20% longer than the neighboring non-elongated part. If the fin has, for example, four grooves, the zone corresponding to two of these grooves can be extended.

However, when the fin has only three grooves, there will probably be only the area corresponding to a groove which will be elongated. In general, it is assumed that the fin will have two to four grooves between pairs of ridges.

The present invention will now be described with the aid of an example, with reference to the accompanying drawings which respectively represent:
Figure 1 is an elevational view from the rear
a drift conforming to this invention
tion;
Figure 2 is a side elevational view of the
derived from Figure 1;
Figure 3 is a plan view of the drift of the
figure 1 ;
Figure 4 is a view from below of the fin
of Figure 1;
Figure 5 is a perspective view from above
a windsurf board with a fin
in accordance with Figures 1 to 4 and fixed in
below it;
Figure 6 is a side elevational view of a
modified form of the drift of the figures
1 to 5 and
Figure 7 is a side elevational view of a
rounded fin, conforms to this
invention.

Figures 1 to 5 of the drawings show a fin 10, intended for a nautical machine. The fin 10 includes a leading edge 14, a trailing edge 16, two lateral faces 18 and 20, a point 22 and a base 24.

As Figures 3 and 4 best show, the faces 18 and 20 are profiled so as to give the fin 10 good hydrodynamic characteristics.

Each face 18 and 20 is formed with three edges 26. The edges 26 extend longitudinally from the leading edge 14, to the trailing edge 16, and are parallel to each other. In addition, each edge 26 on one of the faces 18 or 20, corresponds to a similar edge 26 on the other face, so that the two faces are specular images of one another. In other words, the fin 10 is symmetrical with respect to a vertical plane passing through the line P-P shown in FIG. 1.

The zones between the pairs of edges 26 adjacent to each face of the fin 10 have the form of scalloped grooves 28. The grooves 28 extend longitudinally on one face of the fin 10; between pairs of neighboring artes 26.

As shown in Figure 1, the grooves 28 have a profile which constitutes a transversely continuous curve between the tops of said neighboring edges 26. The grooves 28 direct the stream of water passing over the fin 10 in the longitudinal direction, this is ie from the leading edge 14 towards the trailing edge 16. Consequently, these grooves 28 reduce the tendency of the water to flow transversely with respect to the fin 10. In addition, as indicated, the edge 26 closest to the tip 22 may extend forward relative to the general profile of the leading edge 14. This characteristic makes it possible to retain the water which comes off from the leading edge 14 or which flows transversely and to force it to flow along the neighboring groove 28.

It can be seen in FIG. 1 that the grooves 28 and the edges 26 give each face 18 and 20 a profile having successive increases and decreases in thickness.

In addition, as can be seen in Figure 2, the groove 28 closest to the tip 22 is longer than the other groove 28. In general, the groove 28 closest to the tip 22 will be narrower than the neighboring groove 28, since most of the fins have a profile which tapers towards the point 22.

Preferably, the groove 28 near the tip 22 is at least 20% longer than the neighboring groove 28. The extension of the groove 28 closest to the tip 22 has the effect of extending the rearward corresponding part of the trailing edge.

The groove 28 closest to the point 22 is elongated, because it is in this area of the fin 10 that the greatest torque applied to the machine in service can be exerted, to which the fin 10 is fixed. The improved water guidance near the tip improves the propulsion in a straight line and gives better control and greater directional stability when sailing in a straight line.

The fin, according to the present invention, is normally molded in a single piece of plastic or the like. It has been found that the use of edges 26 increases the rigidity of the fin, compared to conventional fins.

The fin shown in Figures 1 to 5 has improved lift characteristics compared to conventional fins.

The end of the fin 10 close to the base 24 can be simply parallel, or not have an edge 26 close to the base 24, since this end of the fin is less important as regards the improvement of the characteristics of the derivative. However, the end of the fin 10 close to the base 24 is preferably provided with an edge 26 and the area adjacent to the base 24 has the form of a scalloped groove 28, as indicated.

A fin 40, shown in Figure 6, is similar to those shown in Figures 1 to 5, except that the forward projection of the edge 26 near the tip 22 has been omitted, the reference numbers being similar on the other hand to similar parties.

A 50, drift. shown in Figure 7, is similar to those shown in Figures 1 to 5, except that it is a fin with rounded shape, in which the groove 28 near the tip 22 has a projection forward and that the trailing edge14 has a curved shape, the like reference numbers referring, on the other hand, to like parts.

The daggerboards according to the present invention are fixed to a windsurfing board or to any similar device, in the usual manner. This is generally done by inserting the base 24 in a groove at the base of the machine, and by fixing the outlet with a screw.

Modifications and variations which would be obvious to any competent person are considered to be included within the object of the present invention.

Claims (12)

 re arte and the top of a second neighboring arte.  dant transversely between the top of a first  born, so as to obtain a continuous curve, extends  located between them with a festoon profile  created by grooves, and edges and grooves  leading edge to the said trailing edge, and separate  two edges arranged longitudinally from said  lateral of the fin consisting of at least  that, a trailing edge and a point, each face  takes a pair of side faces, a leading edge  nautical equipment, characterized in that it comprises CLAIMS 1. A fin, a rudder or a keel intended for 2. A fin, rudder or keel depending on the  claim 1, characterized in that there are  two to four of the said grooves on each  lateral face between the pairs of neighboring edges. 3. A fin, rudder or keel, depending on the  claim 1 or 2, characterized in that the  two side faces have a hydrody profile  namique. 4. A fin, a rudder or a keel according to one  of the preceding claims, characterized in  what the profiles of the two side faces are  specular images of each other. 5. A fin, a rudder or a keel according to one  any of the preceding claims, charac  terized in that the edges are arranged paral  one to the other. 6. A fin, a rudder or a keel according to one  any of the preceding claims, character-  laughed at in that the arte closest to the poin  protrudes at the front of the leading edge,  to reduce the tendency of water to come off  from the leading edge. 7. A fin, a rudder or a keel, according to one  of the preceding claims, characterized in  what the trailing edge area of the drift corres  laying at least one groove near the point  te of the drift, protrudes rearward by  relative to the trailing edge corresponding to at least  a groove, away from the tip. 8. A fin, rudder or keel depending on the  claim 7, characterized in that the cannelu  re closest to the tip is longer than  the other nearest groove. 9. A fin, rudder or keel depending on the  claim 8, characterized in that the cannelu  re closest to the tip is at least longer  20% less than the nearest neighboring groove. 10. A fin, rudder or keel intended  to a nautical craft, characterized in that it  has two lateral faces, a leading edge,  a trailing edge and a point, where the side faces  the fins are made up of at least two  edges arranged longitudinally, separated by  at least two grooves and where the area of the leak edge  te of the drift, corresponding to at least one rod  lure near the tip of the fin, extends  backwards relative to the trailing edge corres  laying at least one groove distant from the  derivative. 11. A fin, rudder or keel depending on the  claim 10, characterized in that the cane  length closest to tip is longer  than the nearest neighboring groove. 12. A fin, rudder or keel depending on the  claim 11, characterized in that the cane  length closest to tip is longer  at least 20% more than the nearest flute  close.