WO2019150264A1

WO2019150264A1 - A yacht with a hydrofoil

Info

Publication number: WO2019150264A1
Application number: PCT/IB2019/050727
Authority: WO
Inventors: Mark Fraser
Original assignee: Mark Fraser
Priority date: 2018-01-30
Filing date: 2019-01-30
Publication date: 2019-08-08

Abstract

A hydrofoil that that can create a righting moment to hull of a yacht that is not solely reliant on mass of the hydrofoil, more particularly the hydrofoil has one or more wings that can change shape, angle or orientation.

Description

A YACHT WITH A HYDROFOIL

The present invention relates to a yacht with a hydrofoil.

Multihull yachts are more stable to wind induced heel given the wide footprint the hulls provide. Monohull yachts don't have such a wide footprint and tend to heel over at even low wind speeds. Canting keels have been designed to help counteract the heel of a monohull yacht. The canting keel creates a righting moment reliant on a large mass of the keel. The large mass adds to weight of the yacht which may be a disadvantage particularly for racing yachts. It would be an advantage to provide a righting moment to the hull of a monohull yacht without reliance on a weight and moment created by an appendage such a keel.

It is therefore an object of the present invention to provide a yacht that has an appendage that can create a righting moment to hull of the yacht that is not solely reliant on mass of the appendage.

In this specification, where reference has been made to external sources of information, including patent specifications and other documents, this is generally for the purpose of providing a context for discussing the features of the present invention.

Unless stated otherwise, reference to such sources of information is not to be construed, in any jurisdiction, as an admission that such sources of information are prior art or form part of the common general knowledge in the art.

For the purpose of this specification, where method steps are described in sequence, the sequence does not necessarily mean that the steps are to be

chronologically ordered in that sequence, unless there is no other logical manner of interpreting the sequence.

It is an object of the present invention to provide a yacht and/or appendage therefor which overcomes or at least partially ameliorates some of the abovementioned disadvantages or which at least provides the public with a useful choice.

SUMMARY OF INVENTION

In a first aspect the present invention may be said to broadly be said to be a yacht comprising

a hull and

a rig to carry a sail for propelling the yacht through water

a hydrofoil extending from the hull and comprising a mast attached to the hull and a first hydrofoil wing and a second hydrofoil wing extending laterally (beamwise) from each side respectively from said mast, wherein the amount of lift generated by at least one of said first and second hydrofoil wings when the yacht is traveling through water at a given speed can be varied in order to vary the moment applied by the as at least one wing to the mast so that the righting moment exerted on the hull by the mast can be varied.

In a second aspect the present invention may broadly be said to be a a hydrofoil to extend from the hull of a yacht and comprising a mast to be attached to the hull and a first hydrofoil wing and a second hydrofoil wing extending laterally from each side respectively from said mast,

wherein the amount of lift generated by at least one of said first and second hydrofoil wings when the yacht is traveling through water at a given speed can be varied in order to vary the moment applied by said at least one hydrofoil wing to the mast so that the righting moment exerted on the hull by the mast can be varied.

Preferably the amount of lift generated can be varied by changing the angle of attack of at least part of the wing.

Preferably only part of the wing can change the angle of attack.

Preferably the part of the wing that can change angle of attack is distal end of the wing, the proximal end of the wing being rigidly fixed to the mast.

Preferably the distal end of the wing can pivot relative the proximal end of the wing.

Preferably the amount of lift generated can be varied by changing the angle of attack of the entire wing.

Preferably the wing (or part of the wing) is able to pivot relative to the mast about a pivot axis extending laterally to the elongate direction of the mast.

Preferably the pivot axis passes through the mast.

Preferably the pivot axis is perpendicular to the centreline of the yacht.

Preferably the pivot axis is horizontal when the yacht it not rolled over.

Preferably the amount of lift generated can be varied by changing the foil shape (e.g. the camber) of the wing.

Preferably the foil shape is changed by the provision a trim tab on the trailing edge of the wing. Preferably the trim tab is provided along the entire trailing edge of the wing.

Preferably the trim tab is provided at a section the trailing edge of the wing.

Preferably the section is at the distal end of the wing.

Preferably one of the wings only can change shape or change angle of attack.

Preferably both wings can change shape or change angle of attack.

Preferably the wings can change shape or change angle of attack in a manner to change the amount of lift generated in concert to (a) generate the same amount of lift and (b) generate differential amount of lift.

Preferably the lift generated can be negative and/or positive lift.

Preferably the mast is retractable into the hull.

Preferable mast includes ballast.

Preferably the wings include ballast.

Preferably the mast includes a trim tab at its trailing edge.

Preferably the mast can extend and retract from and into the hull.

Preferably the mast does not cant relative the hull.

Preferably the change in lift causes a change in the roll of the yacht.

Preferably the change in lift causes a change in the pitch of the yacht.

In a further aspect the present invention may broadly be said to be a method of changing the roll of a yacht making way through water under sail power the method comprising changing the amount of lift generated by one of the wings of the hydrofoil as herein described.

In a further aspect the present invention may broadly be said to be a method of changing the roll of a yacht making way through water under sail power the method comprising changing the angle of attack of one of the wings of the hydrofoil as herein described.

In a further aspect the present invention may broadly be said to be a method of changing the roll of a yacht making way through water under sail power the method comprising changing the foil shape of one of the wings of the hydrofoil as herein described.

In a further aspect the present invention may broadly be said to be a method of changing the roll of a yacht making way through water under sail power the method comprising rotating one of the wings of the hydrofoil as herein described relative to the mast about rotational axis substantially parallel the elongate direction of the wing.

Preferably the wings are symmetric in aerofoil shape.

Preferably the wings are asymmetric in aerofoil shape (e.g. they have a camber).

In a further aspect the present invention may broadly be said to be a yacht making way through water under sail power, the method comprising one or more of the steps selected from the following

a. changing the amount of lift generated by one of the wings the hydrofoil by at least one of

i. changing the angle of attack of one of the wings the hydrofoil ii. changing the foil shape of one of the wings the hydrofoil iii. rotating one of the wings relative to the mast about a rotational axis substantially parallel the elongate direction of the wing where the hydrofoil is as herein described.

Other aspects of the invention may become apparent from the following description which is given by way of example only and with reference to the

accompanying drawings.

As used herein the term "and/or" means "and" or "or", or both.

As used herein "(s)" following a noun means the plural and/or singular forms of the noun.

The term "comprising" as used in this specification means "consisting at least in part of". When interpreting statements in this specification which include that term, the features, prefaced by that term in each statement, all need to be present but other features can also be present. Related terms such as "comprise" and "comprised" are to be interpreted in the same manner.

The entire disclosures of all applications, patents and publications, cited above and below, if any, are hereby incorporated by reference. This invention may also be said broadly to consist in the parts, elements and features referred to or indicated in the specification of the application, individually or collectively, and any or all combinations of any two or more of said parts, elements or features, and where specific integers are mentioned herein which have known

equivalents in the art to which this invention relates, such known equivalents are deemed to be incorporated herein as if individually set forth.)

The invention will now be described by way of example only and with reference to the drawings in which :

Figure 1: shows a side view of a yacht

Figure 2: shows a partial cut away view of one form a hydrofoil

Figure 3a: shows a side view of a hydrofoil with a wing of the foil in a first position Figure 3b: shows a side view of a hydrofoil with a wing of the foil in a second position Figure 4: shows a front view of the hydrofoil with the wings in a first position

Figure 5: shows a front view of the hydrofoil with the wings in a second position Figure 6: shows a front view of the hydrofoil with the wings in another position

Figure 7: shows a front view of the yacht with the wings in a first position

Figure 8: shows a front view of the yacht with the wings in a first position

Figure 9: shows a mechanism that can be used to control the position of a wing

Figure 10: shows an alternative mechanism

Figure 11: shows an alternative mechanism

Figure 12: shows an alternative form of hydrofoil

Figure 13: shows an alternative form of hydrofoil

Figure 14: shows an alternative form of hydrofoil

Figure 15: shows an alternative form of hydrofoil

Figure 16: shows a view of the wing tip of the wing of Figure 15

As seen in the figures the present invention relates to a yacht 1 and an appendage such as a hydrofoil 5 extending from the hull 2 of the yacht. The yacht may include a primary appendage 100 carrying a hydrofoil and a second or secondary appendage 6 that may function as a rudder. The rudder 6 may also have a hydrofoiling function.

In the preferred form the yacht is a monohull comprising of a single hull. The yacht includes a rig 3 and sails 4 carried by a mast of the rig.

In the preferred form the yacht is of a size capable of carrying at least one adult human. In the preferred form the yacht is capable of carrying a plurality of adult humans. In the preferred form the yacht is at least 500 kilograms in weight. In the preferred form the yacht is able to carry a crew of multiple adults. The hydrofoil 10 is preferably located on the centreline of the hull. It is preferably attached to the hull by a hydrofoil mast 5, at the centreline of the hull.

However, on alternative forms the hydrofoil may depend from the hull off the centreline. In some forms a plurality of hydrofoils of the kind that will hereinafter be described may depend in pairs each side of the centreline of the hull.

In the preferred form the mast is rigidly attached to the hull however in alternative forms the mast may be able to retract and extend from the hull to change the depth to which the hydrofoil extends into the water. In a preferred form the mast is attached to the hull below the waterline if the hull.

The mast 5 is preferably elongate and of a foil shape as can for example be seen in the cross-sectional view of Figure 2. The mast includes a proximal end 20 at where the mast/hull interface exists. The proximal end of the mast may not be the terminal proximal end of the mast. The terminal end of the mast may extend into the hull and be supported in the hull in a braced manner so that the mast is able to depend from the hull in a cantilevered manner. This ensures that the mast remains at a fixed position relative to the hull. However, in alternative forms the mast may be a canting mast able to rotate about an axis that may for example be parallel to the longitudinal axis or centreline of the hull.

The mast is preferably made from a rigid material such as a metal or a composite material which may include carbon fibre. The mast has a leading edge 30 and a trailing edge 31, the leading edge being more proximate to the bow 32 of the hull.

Dependent from the mast 5 is preferably a first wing 110 and a second wing 120. The first wing 110 may extend from the mast in a first lateral direction thereto, and the second wing 120 may extend from the mast in an opposite lateral direction. The angle between the elongate directions of the wings and masts are preferably 90 degrees although other angles may apply.

Each wing includes a leading edge 33 and a trailing edge 34 as seen with reference to the wing 110 in Figure 2. The wing may be attached to the mast in the position as shown, proximate or at the distal end 35 of the mast or set in from the distal end 35 of the mast. The wings may also be more advanced or more trailing to the mast and may be mounted on an alternative or intermediate component of the hydrofoil 100.

The wings may be of an asymmetric form, at least in part along their lengths. The asymmetric shape can be seen for example with reference to Figure 2. At least one of the wings is dependent from the mast in a rotational manner. In the preferred form as seen in Figure 2, the wing 110 is able to rotate about a rotational axis 101 relative to the mast 5. The wing 110 may hence only be attached to the mast via an axle or shaft between the mast and the wing. The rotation of the wing 110 is able to be controlled by a mechanism examples of which will hereinafter be described. The rotation of the wing relative to the mast changes the angle of attack of the wing as the yacht passes through water. This can change the lift provided by the wing. A change in lift of the wing will apply a bending moment to the shaft or axle 38 of or extending into the wing. This bending moment will in turn, as a result of the shaft or axle being cantilevered from the mast 30, apply a force to the mast 30 that will have an impact on the righting moment applied by the hydrofoil 100, to the hull. This can in turn change the lean angle of the yacht as it travels through water.

In a preferred form both wings are able to rotate relative to the mast although it will be appreciated that only one wing can cause a change in the righting moment when the yacht is underway.

The mast and/or wings may include ballast to provide additional righting moment to the hull.

As will be appreciated the lift can be positive lift or negative lift depending on the angle of attack.

As seen with reference to Figure 3A, a rotation of the wing 110 about the axis 101 in a direction to increase the angle of attack will cause an increase in lift on that wing. An opposite rotation of the wing on the other side of the mast will cause a decrease in lift on that wing. As seen in Figure 5, as a result of such rotation of the wings can induce a moment R on the mast and therefore a righting moment on the hull to be exerted. In a neutral position as shown in Figure 4 neither lift or moment may be applied by the wings. Where both wings are able to rotate it is possible for a the same or similar degree of lift to be generated by each of the wings and as seen in Figure 6, a lift L may be exerted on the mast and onto the hull. The hydrofoil is in the preferred form able to lift the hull of the yacht completely clear of the water. Preferably in that condition only the hydrofoil(s) and also rudders if used, are in the water.

With reference to Figure 7 it can be seen that a righting moment R is applied in a clockwise direction to the mast and hence to the hull to act in a direction to provide a righting moment to the hull when the wind W is blowing in the direction as shown on the sails. As described before the righting moment R can be induced by a moment of merely one of the wings as seen in Figure 8.

With reference to Figure 9 there is shown an example of a mechanism by which a wing can be caused to rate. In Figure 9 there is shown an axle 705 that may extend into or otherwise be engaged to the wing (not shown) to define the rotational axis 101.

The shaft may have a sprocket 704 provided at or near a distal end, preferably within the mast of the hydrofoil. The shaft 705 is mounted on bearings (not shown) to ensure a cantilevered relationship is established between the mast and the shaft. The bearings allow for the shaft 705 to rotate relative to the mast about the axis 101. The shaft 705 is preferably keyed or otherwise securely engaged (preferably removably) to the wing. This allows for the shaft 705 to rotate the wing. A chain 703 may extend about the sprocket 704 and extend to an opposed sprockets 704A that may be inside the hull of the yacht. A lever 701 may actuate the sprocket 704A to cause the sprocket 704A to rotate about its axis 702 and thereby cause the shaft 705 to rotate. The mechanism 700 as shown in Figure 9 may be operated manually or hydraulically. For example, a hydraulic arm may connect to the arm 701 for the control and hold of the arm 701. The chain 703 preferably extends through the mast and into the hull. Alternatively, the sprocket 704A is still mounted within the mast and a hydraulic arm may be positioned in the mast for control of the rotation of the sprocket 704A. The sprocket 704A preferably rotates about an axis 702 which is parallel to the axis 705.

In Figure 10 an alternative mechanism is shown relying on a bevelled gear arrangement 714 rather than a chain and sprocket arrangement.

As can be seen in Figure 11, a further variation is shown where for example a motor drive 720 may be provided for direct drive of the shaft 705. The motor may for example be a hydraulic motor. Whilst in a preferred form the entire wing 110 and preferably also 120 are able to move relative to the mast, in an alternative form the lift generated by at least one of the wings may be changed by changing the foil shape of the wing. As seen in Figure 12, a trailing flap 40 of the wing 110, to the stationery leading part 706 of the wing 110 may be provided in a manner that can move or rotate relative to the mast 5. The flap 40 may for example be mounted on an axle or shaft 705 able to rotate about the axis 101. In a preferred form both wings may be so configured.

With reference to Figure 13, it may not be a trailing portion but a distal or intermediate portion of the wing that can be mounted to rotate. As seen in Figure 14, it may be a flap that is not co-terminal at each end, with the primary portion 706 of the wing 110, that can move relative to the mast in order to change the lift of the wing. With reference to Figures 15 and 16, the wing 110 may be of a flexible nature able to twist. In this format the wing 110 may be securely and rigidly mounted to the mast 5 but a shaft 42 may extend through the wing and be secured at a region 44 away from the mast 5, to the wing, and be rotated to cause that portion to twist. A twisting as seen in Figure 16 can change the angle of attack of at least part of the wing and thereby cause a change in the lift of the wing.

Whilst the mast and/or wings may include ballast in alternative forms the weight of the mast and/or wings is not sufficient to contribute to the righting moment of the hull. Preferably a substantial part of the righting moment of the hull is applied to the hull by the hydrofoil.

Where in the foregoing description reference has been made to elements or integers having known equivalents, then such equivalents are included as if they were individually set forth.

Although the invention has been described by way of example and with reference to particular embodiments, it is to be understood that modifications and/or improvements may be made without departing from the scope or spirit of the invention.

In addition, where features or aspects of the invention are described in terms of Markush groups, those skilled in the art will recognise that the invention is also thereby described in terms of any individual member or subgroup of members of the Markush group.

Claims

1. A yacht comprising

a hull,

a rig to carry a sail for propelling the yacht through water, supported by the hull and

a hydrofoil extending from the hull, the hydrofoil comprising a mast attached to the hull and a first hydrofoil wing and a second hydrofoil wing extending laterally from each side respectively from said mast,

wherein the amount of lift generated by at least one of said first and second hydrofoil wings when the yacht is traveling through water at a given speed can be varied in order to vary the moment applied by the at least one wing to the mast so that the righting moment exerted on the hull by the mast can be varied.

2. A hydrofoil to extend from the hull of a yacht and comprising a mast to be attached to the hull and a first hydrofoil wing and a second hydrofoil wing extending laterally from each side respectively from said mast,

3. A hydrofoil as claimed in claim 2, wherein the amount of lift generated by each wing can be varied by changing the angle of attack of at least part of the wing.

4. A hydrofoil as claimed in claim 3, wherein only part of the wing can change in its angle of attack.

5. A hydrofoil as claimed in claim 4, wherein the part of the wing that can change angle of attack is a distal end of the wing, a proximal end of the wing being rigidly fixed to the mast.

6. A hydrofoil as claimed in claim 5, wherein the distal end of the wing can pivot relative the proximal end of the wing.

7. A hydrofoil as claimed in any one of claims 2 to 6, wherein the amount of lift generated can be varied by changing the angle of attack of the entire wing.

8. A hydrofoil as claimed in claim 7, wherein at least one wing (or part of at least one wing) is able to pivot relative to the mast about a pivot axis extending laterally to the elongate direction of the mast.

9. A hydrofoil as claimed in claim 8, wherein the pivot axis passes through the mast.

10. A hydrofoil as claimed in claim 8 or 9, wherein the pivot axis is perpendicular to the centreline of the yacht.

11. A hydrofoil as claimed in any one of claims 8 to 10, wherein the pivot axis is horizontal when the yacht it not rolled over.

12. A hydrofoil as claimed in any one of claims 2 to 11, wherein the amount of lift generated can be varied by changing the foil shape of the wing.

13. A hydrofoil as claimed in claim 12, wherein the foil shape is changed by the provision a trim tab on the trailing edge of the wing.

14. A hydrofoil as claimed in claim 13, wherein the trim tab is provided along the entire trailing edge of the wing.

15. A hydrofoil as claimed in claim 13, wherein the trim tab is provided at a section of the trailing edge of the wing.

16. A hydrofoil as claimed in claim 15, wherein the section is at the distal end of the wing.

17. A hydrofoil as claimed in any one of claims 12 to 16, wherein only one of the wings can change shape or change angle of attack.

18. A hydrofoil as claimed in any one of claims 12 to 16, wherein both wings can change shape or change angle of attack.

19. A hydrofoil as claimed in claim 18, wherein the wings can change shape or change angle of attack in a manner to change the amount of lift generated in concert to (a) generate the same amount of lift and (b) generate differential amount of lift.

20. A hydrofoil as claimed in any one of claims 2 to 19, wherein the lift generated can be negative and/or positive lift.

21. A hydrofoil as claimed in any one of claims 2 to 20, wherein the mast is retractable into the hull.

22. A hydrofoil as claimed in any one of claims 2 to 21, wherein mast includes ballast.

23. A hydrofoil as claimed in any one of claims 2 to 22, wherein the wings include ballast.

24. A hydrofoil as claimed in any one of claims 2 to 23, wherein the mast includes a trim tab at its trailing edge.

25. A hydrofoil as claimed in any one of claims 2 to 24, wherein the mast can extend and retract from and into the hull.

26. A hydrofoil as claimed in any one of claims 2 to 25, wherein the mast does not cant relative the hull.

27. A hydrofoil as claimed in any one of claims 2 to 26, wherein the change in lift causes a change in the roll of the yacht.

28. A hydrofoil as claimed in claim 27, wherein the change in lift causes a change in the pitch of the yacht.

29. A method of changing the roll of a yacht making way through water under sail power, the method comprising one or more of the steps selected from the following

i. changing the angle of attack of one of the wings the hydrofoil ii. changing the foil shape of one of the wings the hydrofoil

iii. rotating one of the wings relative to the mast about a rotational axis substantially parallel the elongate direction of the wing

where the hydrofoil is as claimed in any one of claims 2 to 28.

30. A method as claimed in claim 29, wherein the wings are symmetric in aerofoil shape.

31. A method as claimed in claim 29, wherein the wings are asymmetric in aerofoil shape.

32. A yacht as claimed in claim 1, where the hydrofoil creates sufficient lift to lift the hull out of the water in use.