WO2001000486A1

WO2001000486A1 - Control gear for the sail of a sailing craft

Info

Publication number: WO2001000486A1
Application number: PCT/FI2000/000560
Authority: WO
Inventors: Jan Stenros
Original assignee: Jan Stenros
Priority date: 1999-06-23
Filing date: 2000-06-22
Publication date: 2001-01-04
Also published as: EP1204549A1; FI991427A0; FI991427A; AU5537200A

Abstract

Self-adjusting control gear for a sailing craft (11) provided with a keel structure (12, 13), said control gear comprising a rigid mast (8) having a vertical footing fitted on a base (10) so as to be rotatable with respect to its vertical axis, a supporter structure fitted to the mast, the sail (1) being attached to the supporter structure in an oblique position so that the wind produces in the sail, in addition to a thrust, an upward force tending to lift the craft and transmits the thrust of the sail to the center of gravity of the sailing craft to prevent heeling, and a tackle for the adjustment of the sail. The mast (8), at least in its head portion, is in an oblique position relative to the vertical direction. The supporter structure comprises a supporter (2) substantially transverse to the head of the mast (8) and having a length substantially corresponding to the height of the sail, and transverse supporters (3, 4) of the sail (1), the length of at least one of which substantially corresponds to the width of the sail. The transverse supporter (2) comprises a flexible joint (6) connecting the supporter to the top of the mast (8), and the tackle comprises ropes or equivalent (5, 9) connected to the supporter (2, 3, 4) so as to allow adjustment of the position of the sail, thus achieving automatic adjustment of the pitch axis of the sail (1).

Description

CONTROL GEΞAR FOR THE SAIL OF A SAILING CRAFT

The present invention concerns a control gear for the control of the sail of a sailing craft provided with a keel structure, said control gear comprising a rigid mast with a vertical foot fitted to a base so as to be rotatable with respect to its vertical axis, a supporting structure fitted to the mast, to which supporting structure the sail is fastened in an oblique position so that the wind will generate in the sail, in addition to a driving force, a lifting force and transmits the driving force of the sail to the center of gravity of the sailing craft to prevent tilting, and a tackle for the adjustment of the sail.

A traditional sailing boat provided with a rigid vertical mast is heeled by the wind, with the result that the power of the sail is lost and traveling on the boat is slow and uncomfortable. Therefore, traditional sailing boats need to be equipped with a counterweight to cancel the torque generated by the wind in the sail. The counterweight may consist of a lead weight in the keel, the crew hanging from a harness outside the board of the boat, or a large living weight of a multi-hull boat. A feature common to all such boats is that they sometimes need to reduce or slacken the sail to eliminate an excessive wind force.

Patent application DE 24 31 710 presents a rigid thrust and lift wing profile for water-borne vessels that is automatically adjustable in respect of the rather insignificant roll axis of the sail but not in respect of the angle of incidence, i.e. the pitch axis of the sail. It is controlled using a control gear which comprises a vertical pin mounted on a base so as to be rotatable about a vertical axis. Mounted on its upper end is a plate with a diagonal strut pivoted on each end of the plate, the other ends of the diagonal struts being pivotally connected to the wing profile. By virtue of the pivotal linkage, the wing profile automatically assumes in a traveling position a suitable inclined position, e.g. at an angle of about 45° relative to the horizontal plane, being thus at a suitable angle of incidence to the wind so as to produce a thrust propelling the boat and an upward force lifting the boat. In addition, the thrust of the wing is transmitted to the center of gravity of the boat. Using the solution presented in the above-mentioned application, the rolling moment heeling the boat is avoided. In the application in question, the force for adjusting the wing profile is transmitted via the diagonal struts, the wing structure and the joints of the diagonal struts. This construction produces considerable torsion e.g. at the joints. For instance, in backwash conditions, the twisting forces e.g. on the yaw axis are considerable. In addition, to turn the boat, the wing is swung across the boat. In the case of an upwind tack, the wing may have full thrust on when being turned. Even a moderate gust of wind at a critical moment may overturn the boat. Moreover, for the structure to be strong enough, it should be manufactured from strong and heavy materials. This results in a heavy structure, and the center of gravity of the boat will be too high up. In addition, the structure requires two diagonal struts for each wing. Two diagonal struts increase the weight, the price and the wind resistance. In addi- tion, the structure in question uses a rigid wing profile, which is clumsy and heavy.

The object of the present invention is to eliminate the drawbacks of prior-art solutions and to achieve a new type of self-adjusting control gear for the control of the sail of sailing crafts provided with a rigid mast, in which control gear the sail is automatically adjusted to the right angle of incidence and in which the direction of pull of the sail and the resistive force of the keel cancel each other. The solution of the invention is characterized in that at least the end of the mast is in an inclined position relative to the vertical, that the supporter structure comprises a supporter substantially transverse to the end of the mast and having a length substantially corresponding to the height of the sail, and transverse sail supporters, the length of at least one of which substantially corresponds to the width of the sail, that a transverse supporter comprises a flexible joint connecting the supporter to the end of the mast, and that the tackle comprises ropes or equivalent fastened to the supporters so as to allow adjustment of the position of the sail, automatic adjustment of the pitch axis of the sail being thus achieved.

A sailing boat using a control gear according to the invention will not roll and the power of the sail can be utilized in a controlled manner. The sail responds automatically and sufficiently fast to changes in the direction and force of the wind. When the wind force increases, there arises no moment tending to heel the boat. The stronger the sail force pulling the boat, the stronger is the counteractive force produced by the keel, thus balancing the boat. Moreover, there is no need to adjust the sail all the time as it is adjusted automatically. A boat equipped with a control gear according to the invention can be light and have a large sail area. The sail both propels the boat and at the same time lightens it. A sail having a larger area in relation to the weight of the boat guarantees a higher speed. The speed remains good over a very large range of variation of wind speed. Moreover, the boat is easy to control and balance. The sail control gear of the invention is applicable for use in all types of boat regardless of the hull type of the boat. Therefore, the sail control gear can be used in single-hull or multi-hull boats.

In the following, the invention will be described in detail by the aid of an example with reference to the attached drawings, wherein

Fig. 1 presents a sailing boat with a sail control gear as provided by the invention in neutral position,

Fig. 2 presents a sailing boat as illustrated in Fig. 1 , seen from the stern of the boat, in neutral position,

Fig. 3 presents another sailing boat with a sail control gear as provided by the invention in neutral position,

Fig. 4 presents a sailing boat as illustrated in Fig. 3, seen from the stern, in neutral position, and

Fig. 5 presents a sailing boat with another sail control gear according to the invention in traveling position.

Fig. 1 and 2 present a sailing boat 11 provided with a keel 12 and a mast 8 of tubular construction and a sail 1 of canvas or equivalent. The sail 1 has been fitted to the right shape by using a supporting bar 2 transverse to the top of the mast 8, placed at the front edge of the sail and having a length equal to the height of the sail 1 , and a transverse supporting bar 4 having a length equal to the width of the sail. The sail 1 is fastened to the front end of bar 4. In addition, placed near the ends of bar 2 are two more transverse supporting bars 3, the sail 1 being also fastened to the front ends of these bars 3. The middle part of bar 2 passes through a flexible sleeve 6 fixed to the top of the mast 8. In addition, the other end of bar 4 is fastened to the sleeve 6. The vertical foot end of the mast 8 is so mounted on a base 10 that it can rotate through 360° about its vertical axis. Moreover, the mast 8 is so bent that its upper end is at an angle of about 45° relative to the vertical plane. The transverse bar 2 being perpendicularly connected to the end of the mast, the sail 1 is turned into an angle of about 45° relative to the horizontal plane. Thus, the thrust of the sail 1 in the traveling position is directed partly forward and partly upward and the sail automatically assumes a suitable angle of incidence with respect to the wind. The force vectors of the sail 1 and the keel 12 are opposite to each other, and thus no moment heeling the boat 11 arises. Therefore, the sail 1 will not overturn the boat 11.

To allow adjustment of the sail 1 , there are first control cables 5 fastened to the rear ends of the second transverse bars 3, said rear ends being located somewhat outward from the midpoint between the two halves of the transverse bar 2, the second ends of said control cables being fastened to the ends of a transverse bar 7 at about the middle of the mast 8, with two wire cables 5 connecting each end of bar 3 to the ends of bar 7. By means of the control cables 5, the sail 1 is held in place. In addition, there are a second pair of control cables 9 (sheets) fastened to one end of bar 4 and to wheels 17 placed at the lower end of the mast 8 to allow adjustment of the longitudinal inclination of the sail 1 , i.e. adjustment of the thrust and tack of the sail 1.

The tack of the sail 1 is changed by the lee by releasing the wire cable 9 on the other side and tightening, even when the boat making an upwind tack.

The keel structure may also be implemented as illustrated in Fig. 3 and 4. In this case, the boat has two keels 13 disposed on either side of the boat. The lower end of the keel 13 is obliquely inclined downward under the boat, and the keel is hinged on the boat with a transverse shaft 18 holding the keel by its upper end. In this solution, one of the keels is always drawing the boat deeper on the side opposite to the sail 1. The force vectors of the sail 1 and the keel 13 (keel force 14 and sail force 15 in Fig. 4) are reverse to each other, and no moment tending to heel the boat 11 arises.

In Fig. 5 there are only two transverse bars 3, 4. The end of one bar 4 extends some distance across the supporting bar 2, so it is a suitable place for a return spring 16 which will return the sail 1 to the neutral position in calm weather. It is obvious to the person skilled in the art that the embodiments of the invention are not restricted to the examples described above, but that they can be varied within the scope of the following claims.

Claims

1. Self-adjusting control gear for a sailing craft (11) provided with a keel structure (12,13), said control gear comprising a rigid mast (8) having a vertical foot- ing fitted on a base (10) so as to be rotatable with respect to its vertical axis, a supporter structure fitted to the mast, the sail (1) being attached to the supporter structure in an oblique position so that the wind produces in the sail, in addition to a thrust, an upward force tending to lift the craft and transmits the thrust of the sail to the center of gravity of the sailing craft to prevent heeling, and a tackle for the adjustment of the sail,

c h a r a c t e r i z e d in that

the mast (8), at least in its head portion, is in an oblique position relative to the vertical,

the supporter structure comprises a supporter (2) substantially transverse to the head of the mast (8) and having a length substantially corresponding to the height of the sail, and transverse supporters (3,4) of the sail (1), the length of at least one of which substantially corresponds to the width of the sail,

the transverse supporter (2) comprises a flexible joint (6) connecting the supporter to the top of the mast (8), and

the tackle comprises ropes or equivalent (5,9) connected to the supporters (2,3,4) so as to allow adjustment of the position of the sail, thus achieving automatic adjustment of the pitch axis of the sail (1).

2. Control gear as defined in claim 1 , c h a r a c t e r i z e d in that it comprises a set of first ropes (5) or equivalent, which are connected to each half of the transverse supporter (2) and, via a bar-like part (7), to the mast (8), especially to keep the sail (1) in place.

3. Control gear as defined in claim 1 , c h a r a c t e r i z e d in that it comprises a second set of ropes (sheets) or equivalent (9) fastened to one end of a transverse supporter (4) to allow adjustment of the longitudinal inclination of the sail (1), especially adjustment of the thrust and tack of the sail (1).

4. Control gear as defined in claim 1, ch a racte rized in that the boat has two keels (13) disposed on either side of the boat, that the lower end of each keel is inclined obliquely downward under the boat, and that each keel is mounted on the craft with a transverse shaft (18) supporting the keel by its upper end.