GB2177667A - Windsurfer sail - Google Patents

Abstract

A windsurfer sail, incorporating a removable section of material at its rigid leading edge allows specific leading edge profiles to befitted, hitherto necessitating many sail varieties, each suited to a narrow spectrum of performance application. The sail has a removable luff tube 21 or luff straps 22 and a semi-rigid attachment strip 19 or 20 fixed to and extending substantially throughout the height of the sail. <IMAGE>

Description

SPECIFICATION Windsurfer sail A windsurfer comprises a surfboard having a mast pivotally attached at its base to the upper surface of the board, a sail attached at its luff to the mast, and a boom removably attached to the mast and extending rearwardly along both sides of the sail for attachment thereto at the base of the leech.

In the simplest form, an open-ended flexible tube is attached to the luff and is passed downwardly over the mast and secured at the base.

The manner of attaching the luff to the mast may differ according to the manner in which the windsurfer is to be sailed. For example, for ease of handling it is preferable that the luff tube should be discontinuous and in fact consist of a number of spaced loops which connect the mast to the luff of the sail so that in the event of a capsize, the sail can be righted more easily with water spilling through the free spaces between the loops.

For the purpose of this description, the luff tube will be defined herein as including a continuous tube attached to the sail throughout its length, or alternatively, a number of spaced loops which combine to attach the sail to the mast generally throughout its length.

For high performance sailing the user might select an arrangement known as "rotating asymmetric foil" which is attained by ensuring that a number of battens introduced into the sail extend forwardly to the very edge of the luff so that they tend to lie alongside the mast. With this arrangement, when tacking, the battens pass with a rapid snap action, around the mast to lie on the opposite side thereof. By lying alongside the mast, the battens present the sail tangentially, rather than radially to the mast ensuring a preferred aerodynamic shape.

Again, for racing, an extended luff tube may be adopted; i.e. the width of the tube is enlarged to ensure a smooth transition from sail to mast, which thus avoids the establishment of eddy currents on the windward side.

A few examples have been given above of the many different forms of mast and sail which may be adopted to ensure that the windsurfer is rigged to optimise its performance according to the prevailing conditions. To be fully equipped, the enthusiast must therefore have available a number of different sails each with characteristics to suit a certain condition.

It is an object of the present invention to provide a sail for a windsurfer which may be readily adapted for different conditions, which previously would have required a number of individual sails each adapted for a single purpose.

According to the present invention there is provided a sail for a windsurfer, having a removable luff tube (as herein defined), and at least one semirigid attachment strip fixed to and extending substantially throughout the height of the luff of the sail, in the edge region thereof, said strip providing means for removably attaching the luff tube to the sail.

A number of embodiments of the invention will now be described, by way of example only, with reference to the accompanying drawings in which: Figure 1 is a schematic illustration of a windsurfer of known type; Figure 2 illustrates a windsurfer sail made in accordance with the invention; Figure 3 illustrates two alternative forms of luff tube for attachment of the sail to a mast; Figure 4 illustrates a further alternative form of luff tube; and Figure 5 illustrates an embodiment in which the effective sail area is increased.

Referring now to the drawings, it can be seen from Figure 1 that a conventional windsurfer consists essentially of a surfboard 10 upon which the user stands, a mast 11 pivotally attached at its base to the board 10, a sail 12 attached by a luff tube 13 to the mast 11, and a boom 14 removably attached at 15 to the mast and extending along both sides of the sail 12 to a point 16 at the base of the leech. A number of battens 17 are inserted in pockets in the sail 12 to provide rigidity and to maintain a smooth aerodynamic shape in use.

Referring now to Figure 2, a windsurfer sail made in accordance with the present invention is provided on each face thereof adjacent the luff edge 18, one half of a sliding clasp fastener 19, preferably of a plastics or other non-corrodable material. Spaced inwardly from the luff edge 18, and parallel to the sliding clasp fastener 19 is a strip 20 of so-called "touch and close" fastener, and again, there is a strip of this material on each face of the sail 12.

As can be seen from Figure 3, the sliding clasp fastener 19 may be used for attachment of the sail to the mast 11 by means of a separate luff tube 21 having on its longitudinal free edges the corresponding other halves of the sliding clasp fasteners 19.

Alternatively, the continuous tube 21 may be replaced by a series of spaced loops 22 which combine to form a luff tube and are attached to the sail 12 by means of the "touch and close" fasteners 20.

A fastener of this type requires two interlocking parts, and a length of one of such parts is attached to each free end of each loop 22.

From Figure 3, therefore, it can be seen that by providing a sail with fastener strips 19 and 20, it is a matter of choice whether it be attached to the mast by a continuous tube (as 21) or by a series of loops (as 22), or indeed, by a combination of both.

The provision of the fastener strip 19 which is semi-rigid ensures that the luff of the sail will pass rapidly across the centre line of the mast when tacking, thus increasing the efficiency with which the rotating asymmetric foil trim is achieved.

Referring now to Figure 4, the windsurfer can be readily adapted for racing using an extended (or wider) luff tube 23 which is attached to fastener strip 20 in a manner similar to standard luff tube 21. The extended luff tube 23 may contain pockets 24 adapted to receive short stiffening battens 25 whose rigidity and position can be selected accord ing to the conditions of use.

In addition, other trimming aids may be incorporated into the removable luff, to provide different trimming profiles for different conditions. For example, there may be included flotation devices for buoyancy and which create a semi-rigid profile.

Referring now to Figure 5, and in accordance with a further novel aspect of the present invention, the sail area may be increased substantially by attaching a luff extension 26 to the sail 12 proper, again by means of the fastener strip 19. In this embodiment, the straight mast 11 is replaced by a pre-shaped mast 27 to conform to the sail extension 26 thus providing a four-sided sail with substantially increased effective area. A sail of this shape may be attached to a pre-formed non-linear mast, by a fixed luff tube or one which is attached by a sliding clasp fastener to the two forward edges forming the luff of the sail.

The invention is not limited to the above examples only, many variations, such as might readily occur to one skilled in this art, being possible without departing from the scope thereof.

Claims (8)

1. A wing incorporating a removable panel on its rigid leading edge, which by its attachment, alters the nature of the generated lift; the science of which is true to sails, hang-gliders, micro-light aircraft and any locomotory device of similar design.

2. A wing incorporating a removable luff on its rigid leading edge, which by its attachment, alters the nature of the generated lift; the science of which is true to sails, hang-gliders, micro-light aircraft and any locomotory device of similar design.

3. A sail incorporating a removable panel on its rigid leading edge, which by its attachment, alters the nature of the generated lift.

4. A sail incorporating a removable luff on its rigid leading edge, which by its attachment, alters the nature of the generated lift.

5. A windsurfer sail incorporating a removable panel on its rigid leading edge, which by its attachment, alters the nature of the generated lift.

6. A windsurfer sail incorporating a removable luff on its rigid leading edge, which by its attachment, alters the nature of the generated lift.

7. A windsurfer sail as is claimed in claim 5 and claim 6, wherein the specific means of attachment utilizes a drawstring arrangement.

8. A windsurfer sail substantially as described herein with reference to Figures 1 to 5 of the accompanying drawing.