GB2164307A - Sail rigs - Google Patents

Abstract

A sail rig for a sailboard or other craft comprises a sail, two masts 2, 3 coupled together at or near their bases and pivotally mounted on the board or craft, the sail being attached to each mast along a respective edge of the sail; and a wishbone boom 6 arranged between the masts to space them so that the sail adopts a fanlike configuration between them, and to provide a hand hold for the sailor of the board. <IMAGE>

Description

SPECIFICATION Improvements in or relating to sail rigs This invention relates particularly but not exclusively to the sails of sailboards and craft using the free sail system where the mast or masts are flexibly mounted on the board or hull.

The art of board sailing is difficult and one of the most difficult although necessary manoeuvres is jibing. This is particularly difficult in a high wind. In one aspect this invention seeks to eliminate the need to jibe and therefore increases the speed of the craft because wind power is not lost when the sail is jibed.

Downward manoeuvres are therefore uninterrupted and much faster.

In that one aspect the invention provides a sail rig suitable for a sailboard or other craft comprising a sail which is attached to two masts joined at or near their bases and pivotally mounted on the board or craft.

The sail therefore forms a fan-like configuration between the two masts to which may be attached a wishbone-boom which can space the two masts, and which the sailor can hold. The boom may have two uphaul lines, one fixed near the extremity of each end of the wishbone-boom.

In a further aspect of the invention the two aforementioned masts are bent in such a way that they can be arranged to curve towards the windward direction, the curvature being substantially at right angles to the plane of the sail. The masts can have symmetry or asymmetry about their mid-points thereby forming a sail of concave configuration.

The boom may be a single strut and may be of curved to lie parallel with the sail in use, being spaced from the sail at each end of the boom by means of a spacer strut to the mast. The boom may have a second curved element sheathed within the sail.

It is well known in aircraft technology that in order to create extra lift particularly on landing and take-off the wing extends a leading edge slat or a trailing edge flap. The slats extend over the leading edge of the wing, and give the wing extra lift and lower the speed at which the wing stalls.

In a further aspect the invention provides a sail rig comprising a sail attached to a mast or two masts and a boom to span the sail; and a respective leading edge flexible or rigid slat attached to at least one of the masts. The masts or masts may preferably be pivotally mounted on the craft and said slat or slats may preferably be pivotally mounted on the relevant mast so that it can be swung from the windward to the leeward side of the mast prior to or during tacking, to operate again as a slat after tacking. When there are two masts each fitted with a respective slat, the slat attached to the trailing mast in use may preferably be pivoted round that mast to act in the manner of a trailing edge flap on the windward side of the mast.

In a further aspect the invention provides a mast or masts which are curved and each pivotally mounted in such a way that they can be rotated about their longitudinal axes so that the direction of curvature can be changed from one side of the sail to the other by such rotation of the mast or masts. When two such curved masts are provided they may be rotatably connected so that they rotate together, by means of gears or the like. In such an arrangement one curved mast may be configured to form a curved boom of otherwise conventional arrangement.

In order to promote a fuiler understanding of the above and other aspects of the above mentioned inventions, some embodiments will now be described, by way of example only, with reference to the accompanying drawings in which: Figure 1 shows a first embodiment of the invention with two masts, Figures 2 and 2 C show a second embodiment of the invention, Figures 3 and 3A show an alternative arrangement for the sail rig of the embodiment of Figure 1, Figures 4 and 5 show a further alternative arrangement for the sail rig of the embodiment of Figure 1, Figures 6 and 7 show a further embodiment of the invention fitted with slats, Figure 8 shows a further embodiment of the invention with a rotatable mast, and Figures 9 and 10 show a further embodiment of the invention with a rotatable mast and a rotatable boom.

The embodiment in figure 1 has a sail attached to two masts 2 and 3 which are joined at 4 and pivotally mounted through flexible joint 5 on the sailboard or other craft 12. A wishbone-boom 6 is provided which can form a strut to locate the masts and can also be held by the sailor.

It can be seen that the symmetry or near symmetry of the rig means that the leading and trailing edges of the sail can be reversed and that the sail could be used to sail in either direction off the wind without the need for jibing.

Two uphaul ropes 10 and 11 may be provided so that the chosen leading mast can be uphauled to coincide with the hull direction thereby eliminating a tack or jibe manoeuvre.

Another aspect of the invention is that the sail can be shaped between points 7 and 8 to suit the desired characteristics. The sail can be straight as shown by the dotted lines between 7 and 8 or can be cut below this dotted line or extended above to gain extra head area with or without the aid of battens 9 to provide rigidity as is commonly known to the art.

It can be seen therefore that the embodiment provides a sailor a free sail system where: 1. The sail configuration eliminates the need to jibe 2. The sail is of such symmetry or near symmetry that either edge can form the leading edge with the other edge forming the trailing edge.

3. There may be two uphaul lines so that either edge of the sail rig can be raised first 4. there are two masts holding one sail.

In the embodiment of figure 2 a mainsail 1 is attached to curved masts 2 and 3 which are joined at 4 and pivotally mounted through flexible joint 5 on the sail board or other craft 12. A wishbone-boom 6 is provided which can form a strut to locate the masts and can also be held by the sail, as described in the embodiment above. Figure 1 C shows the curvature of mast 2 which gives the sail a concave form and fullness for high efficiency and controllability. masts 2 and 3 can have symmetry about their centre axes AA' and BB' respectively so that they are identical in form and therefore have interchangeability.

Figures 3 and 3 A show a similar sail 1 with boom 6 as a single strut, with Figure 3 A showing the curvature of the boom being substantially parallel to that of the sail in order to follow the airflow.

Figures 4 and 4 A show another embodiment of the invention in plan view where a second boom strut 7 is built of such a curvature to correspond with that of the sail 1 in its operative state and is incorporated within a pocket or sheath within the sail.

It can be seen therefore that these aspects of the invention provide a sail where; 1. The masts are curved in a direction substantially at right angles to the plane of the sail 2. The masts can be symmetrical of assymmetrical about their central axes 3. A one-piece boom which can be curved to be parallel with the sail 4. a boom which can include a further strut or member which can be located within a pocket in the sail The embodiment shown in Figure 6 has a mainsail 1 attached to a mast 2 and a boom 6 with a leading slat 7, so that it can be rotated around the mast from, for example, the windward to the leeward side of the sail. Figure 7 shows another embodiment of the invention where slats 7 and 8 are fitted by the same method to a Fansail as described above with reference to Figures 1, 2, 3, 4, or 5 above.The slats may be made of a flexible material and mounted on shaped struts by their leading edges as indicated at 10 and 11. In such an arrangement the slats take up an aerofoil form corresponding to the shape of the shaped struts on either side of the sail in use. As also indicated in Figure 6 be noted, the slat 7 may be rigid and have permanent curvature built into it and rotate about the vicinity of the mast at mounting points 12 and 9.

A further embodiment of the invention is shown in Figure 6 where slat 7 has symmetry about axis "AA" so that it can be removed and replaced on the other side of the sail when point 20 on flap 7 would become uppermost.

With the arrangement of Figure 7, it should be noted that when one of the slats 7 is at the leading edge of the sail in use, the other slat is inevitably at the trailing edge of the sail. That trailing edge slat may be rotated around the trailing edge mast so that it lies to the windward side of the sail in use and acts in the manner of a trailing edge flap.

A further embodiment of the invention is shown in Figures 8, 8 A, and 8 B, where a sail 1 is attached to a curved mast 2 which is curved towards the wind; and is arranged to be rotatable at its base in such a way that, for example, lever 3 rigidly fixed to the mast can rotate the mast so that the curvature of the mast is swung to the other side of the sail as shown in position B.

It can be seen therefore that these embodiments of the invention provides sail rig where: 1. Leading edge slats are provided for the sail and can be fixed in such a way to be able to be swung to the other side of the sail 2. Trailing edge flaps are provided for a sail and can be fixed in such a way to be able to be swung to the other side of the sail 3. The slats/flaps mentioned in 1 and 2 can be symmetrical or asymmetrical about their longitudinal, lateral and transverse axes (thereir X, Y, and Z axes) 4. The slats/flaps can be made out of flexible material to take up variable curvatures 5. The mast or masts which are curved can be rotated so that the curvatures is on the windward side of the sail.

Figure 9 shows a further embodiment in which a main sail 1 is rigged between a curved mast 2 and a curved boom 6. The rotations of the mast and boom are coupled together by means of suitable gearing such as the bevel gears shown schematically in Figure 9. Thus on rotation of the mast by means of the lever 11, the boom also rotates in the same sense to swing the direction of curvature of both the mast and the boom to one side or the other. Thus the curved members may be made to shape the sail advantageously for when the wind is on either side of the craft. Means, not shown, is provided to lock the mast and boom against rotation once the have been so swung. Figure 10 shows in a front view how a mast of Figure 9 may be supported by means of conventional stays 15 and 16 which are attached to a collar 17 which is in turn rotatable on the mast. The collar 17 may be positioned at any suitable height up the mast, including at the very top, and fore and aft stays may also be attached to the collar.

It can be seen therefore that this embodiment of the invention provides a sail rig for a sailing craft where: 1. The mast and boom are curved towards the windward direction at any time 2. The mast and boom can be rotated to show their curvature towards the windward direction on each tack 3. The must can be mounted in the orthodox fashion with stays.

Claims (10)

1. A sail rig for a sailboard or other craft comprising a sail, two masts coupled together at or near their bases and pivotally mounted on the board or craft, the sail being attached to each mast along a respective edge of the sail; and a wishbone boom arranged between the masts to space them so that the sail adopts a fanlike configuration between them, and to provide a hand hold for the sailor of the board.

2. A sail rig as claimed in claim 1, in which the boom is provided with an uphaul line at or near each end.

3. A sail rig comprising a sail attached to a mast or two masts and a boom arranged to span the sail; and a respective leading edge slat attached to at least one of the masts.

4. A sail rig as claimed in claim 3, in which the slat is formed of flexible material. and mounted by its leading edge on shaped struts on the mast, so that in use it takes up a aerofoil shape corresponding to the strut.

5. A sail rig as claimed in claim 3 or 4 in which the slat is pivotally mounted on such mast so that it may by swung to lie on the leeward side of the sail after tacking or similar manoeuvres.

6. A sail rig as claimed in any of claims 3 to 5, in which such a slat is fitted to each said mast, and the arrangement is such that the one slat which is at the trailing edge of the sail in use, may be swung about the trailing mast to act as a trailing edge flap.

7. A sail rig as claimed in claims 1 and 3, 4, or 5.

8. A sail rig for a sail board or other craft comprising a sail attached to a mast, the mast being curved and pivotally mounted on the board or craft so that the direction of curvature of the mast may be changed from one side of the sail to the other so as to present a concave sail configuration to the incident wind.

9. A sail rig as claimed in claim 7, in which the sail is set between such mast and a boom, the boom also being curved.

10. A sail rig as claimed in claim 9, in which means is provided to lock the gearing and thus the mast and boom against rotation.

10. A sail rig as claimed in claim 8, in which the mast and boom are rotatably coupled so that they rotate together, by means of gearing.