GB2508660A

GB2508660A - A control arrangement for a wind powered vehicle

Info

Publication number: GB2508660A
Application number: GB1222153.7A
Authority: GB
Inventors: Bruce Nicholas Martin
Original assignee: Individual
Current assignee: Individual
Priority date: 2012-12-10
Filing date: 2012-12-10
Publication date: 2014-06-11
Anticipated expiration: 2032-12-10
Also published as: WO2014091210A1; US20170183071A1; GB2508660B; GB201222153D0

Abstract

A control arrangement 1 for a kite 6 is attached to a boat 2. The control arrangement automatically tracks the movement of the kite as the kite moves relative to the boat without any external control or energy input. The control arrangement ensures that the kite flies so that the line of action 15 of the kite always extends through the centre of lateral resistance 14 of the boat. This enables the kite to pull the boat without applying any heeling moment to the boat. The control arrangement could be used with a land based vehicle and the kite could be replaced with a collapsible wing.

Description

Title: A Control Arrangement for a Wind Powered Vehicle The present invention relates to a control arrangement for a wind powered vehicle and more particularly relates to a control arrangement to control an aerofoil section attached to a vehicle.

A conventional sailing boat incorporates a sail attached to a mast and a boom.

The force of the wind on the sail propels the boat along the water. The force of the wind on the sail also applies a heeling moment to the boat which causes the boat to heel to one side. To resist the heeling moment sailing boats have wide hulls and/or carry significant ballast, each of which increase the water resistance against forward motion. The maximum area of the sails is limited by the capacity of the boat to resist the heeling moment.

The speed of a boat can be defined in terms of the Froude number. The Froude number Frof any boat is calculated using the following equation: Pr=f Where v is the velocity of the boat, g is the acceleration due to gravity and L is the length of the boat at the water line level.

A displacement hull moves through the water, displacing the water as it goes, with the boat being supported by hydrostatic lift (buoyancy). A planing hull, on the other hand, skims over the top of the water with the boat being supported by hydrodynamic lift. Due to hydrodynamic effects, the resistance on a displacement hull increases rapidly above a speed of around Fr = 0.45. To achieve speeds in excess of around Fr = 0.45, the hull must begin to plane to obtain support from hydrodynamic lift forces, instead of from the hydrostatic (buoyancy) forces which dominate at lower speeds.

The length displacement ratio of a boat can be used as a guide to the performance of a boat above a speed of Fr = 0.45. The length displacement ratio DLR is calculated using the following equation: A3 Where L is the length of the boat at the water line level and A is the displacement of the boat. As a guide, a sailing boat with a length displacement ratio of less than 5.7 will not plane and will therefore not exceed a speed of around Fr = 0.45. As a result of the requirement for a wide hull and/or ballast to resist the heeling moment from the sails, it is very difficult to build standard yachts with a length displacement ratio larger than 5.2.

Therefore most yachts are limited to a maximum speed of around Fr = 0.45.

It has been proposed previously to power a boat using a kite instead of a sail in order to minimise heeling. One such conventional arrangement is disclosed in US Patent No. 6003457. The kite arrangement disclosed in this document is able to reduce the heeling action on a boat but the driving force from the kite must be controlled actively by an arrangement which adjusts the vertical inclination and plan alignment of an arm to which a kite is attached, this requires external control and energy input. In addition, the steering of the kite and the angle of incidence of the kite to the wind are controlled by a system mounted on the arm to which the kite is attached, this makes it difficult to manually steer the kite and to manually control the angle of incidence of the kite to the wind.

The present invention seeks to provide an improved control arrangement for a wind powered vehicle while also minimising or eliminating heeling.

According to the present invention, there is provided a control arrangement for a wind powered vehicle, the arrangement comprising: a first elongate support member, a second elongate support member which is pivotally mounted at a pivot point to the first support member, the second support member having a free end which is remote from the pivot point, a flexible elongate drive line which is attachable at one end to a wind powered drive element which, in use, applies a drive force to the drive line, wherein the drive line extends slideably through a first mounting point adjacent the free end of the second support member such that the drive force applies a first moment to the second support member about the pivot point, a biasing arrangement configured to convert the drive force into a biasing force and to apply the biasing force to the second support member at a point between the free end and the pivot point, the biasing force applying a second moment to the second support member which at least partly cancels the first moment to reduce the overall moment to the second support member in a first plane, and a base unit which is rotatably attached to the first support member, the first support member being rotatable by any number of 36O rotations or part rotations relative to the base unit and configured to rotate relative to the base unit until the second support member aligns with the drive force and no overall moment is applied in a second plane to the second support member.

Preferably, the biasing arrangement comprises a second mounting point which is provided on the second support member between the free end and the pivot point, the biasing arrangement further comprising a fixing point provided on the first support member, the drive line extending slideably through the second mounting point and being fixed to the first support member at the fixing point.

Conveniently, the drive line extends a plurality of times between the second mounting point and the fixing point.

In one embodiment, the second mounting point is positioned substantially half way between the free end and the pivot point.

Preferably, the drive line extends twice between the second mounting point and the fixing point.

In another embodiment, the second mounting point is positioned on the second support member at substantially one third of the distance between the free end and the pivot point.

Advantageously, the drive line extends three times between the second mounting point and the fixing point.

Preferably, the drive line extends at least partly around a rotatable element which is provided at the pivot point.

Conveniently, the arrangement further comprises two flexible elongate control lines which are attachable at one end to the wind powered drive element to control the wind powered drive element.

Advantageously, the control lines extend at least partly around the rotatable element.

Preferably, the control lines and the drive lines wind onto or reel out from the rotatable element as the rotatable element rotates.

Conveniently, the base unit incorporates an aperture and the elongate axis of the first support member is at least partly aligned with the aperture in the base unit.

Advantageously, the control lines extend through the aperture in the base unit.

In one embodiment, the arrangement further comprises two crew lines which are connected respectively to the two control lines, the crew lines extending through the aperture in the base unit.

Conveniently, the control lines or the crew lines are configured to be pulled in or let out manually by a user.

In one embodiment, the control lines or the crew lines are connected to a power bar which is operable to be controlled by the hands of a user.

In another embodiment, the control lines or the crew lines are attached to a foot bar which is operable to be controlled by the user's feet.

In a further embodiment, the control lines or the crew lines are connected to a mechanical control arrangement.

Advantageously, the fixing point is moveable to adjust a heeling moment applied by the control arrangement.

In one embodiment, the arrangement further comprises an arrangement for adjusting the position of the fixing point automatically to stabilise the control arrangement if the control arrangement is subjected to a rolling moment.

Preferably, each of the lines is releasably attached to an attachment element and wherein the length of the lines is adjustable by winding in or letting out the lines from the releasable attachment.

Conveniently, the releasable attachment is a rotatable drum which is operable to rotate to wind in or let out the lines.

Advantageously, the arrangement further comprises a wind powered element which is connected to one end of each line.

Preferably, the wind powered element comprises an aerofoil section.

In one embodiment, the wind powered element is a kite.

In another embodiment, the wind powered element is a wing.

Preferably, the wing is collapsible.

Conveniently, the wind powered element incorporates a float arrangement which floats on water.

Advantageously, the base unit is mounted to a watercraft.

Preferably, the watercraft comprises a keel, centreboard or a single element comprising both a keellcentreboard and rudder to resist lateral movement of the boat.

Conveniently, the longitudinal axis of the first support member is aligned with the longitudinal axis of the keel or centreboard.

Advantageously, the length of the second support member is selected so that the direction of the force exerted by the wind powered element on the drive line extends substantially through the centre of lateral resistance of the combined hull, keel or centreboard, rudder and other appendages when there is no overall moment applied to the second support member in the first or second planes.

In another embodiment, the base unit is mounted to a land based wind powered vehicle.

In a further embodiment, the base unit is mounted to a snow or ice based wind powered vehicle.

In a still further embodiment, the base unit is configured to be attached to a boat.

In one embodiment, the base unit is attached directly to a keel or centreboard which is configured to be attached to a boat.

In another embodiment, the base unit is attached directly to a rudder which is configured to be mounted to a boat.

In a further embodiment, the rudder is mounted to a boat which does not incorporate of keel or centreboard.

Preferably, the rudder is pivotally mounted to or near the rear of a boat.

Conveniently, the base unit is attached to a boat.

In one embodiment, the boat is a kayak.

In another embodiment, the boat is a dinghy.

In a further embodiment, the boat is a yacht.

In a still further embodiment, the boat is a boat selected from a group consisting of a raft, surfboard, ship, canoe, monohull, multihull, displacement vessel, planing vessel or a vessel supported on hydrofoils.

In one embodiment, the control arrangement is mounted to a planing vessel at or near the rear of the planing vessel.

In another embodiment, the boat comprises at least one hydrofoil element.

In order that the invention may be more readily understood, and so that further features thereof may be appreciated, embodiments of the invention will now be described, by way of example, with reference to the accompanying drawings in which: Figure 1 is a schematic diagram showing a control arrangement of one embodiment of the invention mounted to a boat, is Figure 2 is a view corresponding to figure 1 showing the control arrangement tracking a kite as the kite moves up and down, Figure 3 is a plan view of the embodiment shown in figure 1 with the control arrangement tracking a kite as the kite rotates about a vertical axis, Figure 4a is a schematic diagram showing the control arrangement of figure 1 for an embodiment of the invention in which portions of the drive lines and portions of the control lines are incorporated into the biasing arrangement, Figure 4b is a schematic diagram showing the control arrangement of figure 1 for an embodiment of the invention in which portions of the drive lines only are incorporated into the biasing arrangement, with the drive lines terminating at the foot of the mast, Figure 4c is a schematic diagram showing the control arrangement of figure 1 for an embodiment of the invention in which portions of the drive lines only are incorporated into the biasing arrangement, with the drive lines terminating at the third point of the boom, Figure 5 is a schematic diagram illustrating the geometric terminology adopted in the analysis of the control arrangement in an embodiment of the invention, Figure 6a is a schematic diagram of a further embodiment of the invention which incorporates a biasing arrangement with drive lines and control lines attached to a midpoint of a support arm, Figure 6b is a schematic diagram for an embodiment of the invention in which portions of the drive lines only are incorporated into the biasing arrangement, with the drive lines connected to a midpoint of the support arm and terminating at the toot of the mast, Figure 6c is a schematic diagram for an embodiment of the invention in which portions of the drive lines only are incorporated into the biasing arrangement, with the drive lines connected to a midpoint of the support arm and terminating at the mid point of the support arm, Figure 7 is a schematic diagram of the control arrangement shown in figure Gb, Figure 8 is a schematic perspective view of the control arrangement shown in figure 7, Figure 9 is a close-up schematic perspective view of part of the control arrangement shown in figure 8, Figure 10 is a schematic view showing the control arrangement of figure 9 attached to part of a vehicle, Figures 11 a-i id show diagrammatic sectional views of a first support member of an embodiment of the invention mounted rotatably to a base unit with the support member rotated at different angles, Figure 12 is a schematic diagram of a control arrangement for use with an embodiment of the invention to enable a user to control the arrangement using their feet and legs, Figure 13 is a diagrammatic view of a further control arrangement for use with an embodiment of the invention for a user to control the arrangement with their feet and legs, Figure 14 is a schematic view of part of an embodiment of the invention is illustrating an adjustable fixing point, Figure 15 is a schematic diagram showing a tuning line attached to the drive line of an embodiment of the invention, Figure 16 is a schematic diagram of a control arrangement for use with an embodiment of the invention which incorporates heel tuning, Figure 17 is a schematic diagram of part of an embodiment of the invention which incorporates a winding drum to wind in and let out the drive lines, Figure 18 is a schematic diagram of a still further embodiment of the invention in which a control arrangement is attached to a centreboard which may be removably attached to a kayak, Figure 19 is a schematic diagram showing an analysis of a planing motor boat, Figure 20 is a view corresponding to figure 19 with a control arrangement of an embodiment of the invention attached to the rear of the boat, Figure 21 is a view corresponding to figure 19 with a control arrangement of an embodiment of the invention attached to the front of the boat, Figure 22 is a schematic diagram illustrating the moments applied to the boat when the control arrangement is mounted to the front of the boat, Figure 23 is a schematic diagram showing the moments applied to the boat when the control arrangement is mounted near the boat's centre of mass, Figure 24 is a schematic diagram illustrating the moments applied to a boat when the control arrangement is mounted slightly to the rear of the boat's centre of mass, Figure 25 is a schematic diagram illustrating the moments applied to the boat when the control arrangement is mounted at the rear of the boat, Figure 26a is a schematic diagram illustrating the optimum location of the control arrangement at the rear of a boat with a hydrofoil at the bow at low speed while the boat operates as a displacement vessel, Figure 26b is a schematic diagram illustrating the optimum location of the control arrangement at the rear of a boat with a hydrofoil at the bow at moderate speed as the boat starts to plane, Figure 26c is a schematic diagram illustrating the optimum location of the control arrangement at the rear of a boat with a hydrofoil at the bow at high speed as the boat planes, Figure 27 is a schematic diagram showing a control arrangement of an embodiment of the invention mounted at the rear of a dinghy, Figure 28 is a schematic diagram showing a pair of trim tabs mounted to a boat, Figure 29 is a schematic diagram of a manual control arrangement for use with an embodiment of the invention, Figure 30 is a schematic diagram of a manual control arrangement using a power bar for use with an embodiment of the invention, Figure 31 is a schematic diagram of a collapsible wing attached to a control arrangement positioned on a boat, Figure 32 is a schematic diagram of the collapsible wing shown in figure 31, Figure 33 is a schematic perspective view of the collapsible wing shown in figure 31, Figure 34 is a schematic diagram of a float for use with a wind powered element of an embodiment of the invention, Figures 35a-35c show the collapsible wing of figure 31 at different stages as the wing opens, and Figure 36 is a schematic diagram showing the collapsible wing as it is ready to be launched from a boat.

Automatic tracking Referring initially to figure 1 of the accompanying drawings, a control arrangement 1 is attached to a watercraft such as a boat 2. The operating principles of the control arrangement 1 will now be described before the control arrangement 1 is described in detail.

The control arrangement 1 incorporates a first support member in the form of a mast 3 and a second support member in the form of an arm 4. One end of the arm 4 is pivotally attached to the mast 3 at a pivot point 5. The lower end of the mast 3 is rotatably attached to a base unit (not shown).

In the arrangement shown in figure 1, the base unit is attached to the boat 2.

In other embodiments, the base unit is configured to be removably attached to a boat or another vehicle by an attachment means, such as a push connector, bolt or clamping arrangement.

The control arrangement 1 is for use with a wind powered element which, in this embodiment, is a kite 6. The kite 6 is preferably a kite of the type typically used for kite surfing. In other embodiments, the control arrangement 1 is for use with another wind powered element, such as an aerofoil section. In further embodiments, the wind powered element is either a fixed wing or a collapsible wing.

The kite 6 is connected to the control arrangement 1 by at least one flexible elongate drive line which may also be known as a drive line. Embodiments of the invention may incorporate any number of drive lines. However, in this embodiment, there are two flexible elongate drive lines 7, 8. The drive lines 7, 8 are attached to the kite 6 and attached slideably to a free end 9 of the arm 4, for instance by a pulley. The drive lines 7, 8 transfer the majority of a drive force F exerted by wind on the kite 6 to the control arrangement 1.

In this embodiment, two flexible elongate control lines 10, 11 are attached at either end of the kite 6. In other embodiments there may be a greater or fewer number of control lines.

The control lines 10, 11 extend from the kite 6 to the free end 9 of the arm 4.

The control lines 10, 11 are used to steer the kite 6 and to control the angle of incidence of the kite 6 to the wind. It is to be appreciated that the control lines 10, 11 are not loaded with a significant portion of the drive force F. The control arrangement 1 incorporates a biasing arrangement 12 which applies a biasing moment to the arm 4 about the pivot point 5. The biasing arrangement 12 comprises portions of the drive lines 7, 8. In other embodiments the biasing arrangement 12 comprises portions of the drive lines 7, 8 and portions of the control lines 10,11. The configuration of the biasing arrangement 12 will be discussed in detail below.

In the arrangement shown in figure 1, the boat 2 is a yacht which incorporates a keel 13. The keel 13 provides a lateral resistance in the water which resists lateral movement of the boat through the water. The centre of lateral resistance 14 is defined notionally at the midpoint of the keel 13.

The effect of the control arrangement 1 of embodiments of the invention is to track the movement of the kite 6 so that a line of action 15 which is aligned with the drive force F exerted by the kite 6 on the control arrangement 1 passes through the centre of lateral resistance 14, as shown in figure 1.

Without any external control or energy input the control arrangement 1 automatically tracks the movement of the kite 6 in a first plane as the kite 6 moves up and down and ensures that the line of action 15 always passes through the centre of lateral resistance 14. This principle is illustrated in figure 2 with the kite 6 moving from a lower position to a higher position, with the line of action 15 always passing through the centre of lateral resistance 14.

The mast 3 is rotatably attached to the base unit to allow the mast 3 to rotate freely around the longitudinal axis of the mast 3 by any number of 3600 rotations or part rotations. The control arrangement 1 can therefore rotate freely relative to the boat 2. This enables the control unit 1 to track the movement of the kite 6 in a second plane as the kite 6 rotates around the boat 2, as shown in figure 3.

The optimum plan orientation and vertical alignment of the control arrangement 1 to minimise or eliminate heeling is freely found as a natural outcome of the geometry and rotational releases of the control arrangement 1.

The control arrangement 1 freely tracks the kite 6 vertically and on plan is without any external control or energy input.

Biasing arrangement The control arrangement 1 of an embodiment of the invention will now be described in more detail with reference to figure 4a. In this embodiment, the drive lines 7, 8 (only one of which is visible in figure 4a) and the control lines 10, 11 (not shown in figure 4a) extend slideably through a first mounting point 16 which is provided at or adjacent to the free end 9 of the arm 4. In other embodiments, the drive lines 7, 8 are joined together before reaching the arm 4 and a single drive line extends through the first mounting point 16.

The drive lines 7, 8 and the control lines 10, 11 extend slideably through a mounting point 18 provided on the arm 4 at a position substantially one third of the way along the length of the arm 4 between the pivot point 5 and the free end 9. In this embodiment, the drive lines 7, 8 and the control lines 10, 11 extend from the second mounting point 18 and extend slideably through a third mounting point 19 positioned at the base of the mast 3. The drive lines 7, 8 and the control lines 10, 11 extend from the third mounting point 19 back up to the arm 4 and extend slideably through a fourth mounting point 20 provided on the arm 4 at approximately the same location as the second mounting point 18. The drive lines 7, 8 and the control lines 10, 11 extend from the fourth mounting point 20 to a fixing point 21 at the base of the mast 3. In this embodiment, all of the mounting points are pulleys.

At each mounting point 16, 18, 19 and 20 a separate pulley is provided for the drive lines 7, 8 and for each of the control lines 10, 11. This allows the control lines to run through the pulleys independently of the drive lines.

It is to be appreciated that portions of the drive lines 7, 8, the control lines 10, lithe second, third and fourth mounting points 18-20 and the fixing points 21 all constitute components of the biasing arrangement 12. In this embodiment, the drive lines 7, 8 and the control lines 10, ii are looped three times between the mast 3 and the arm 4. The triple looping of the drive lines 7, 8 and the control lines 10, ii is selected to match the one-third distance position of the second mounting point 18 along the length of the arm 4. The triple loop of the biasing arrangement 1 exerts a control force between the mast 3 and the arm 4 which is three times the drive force F. The operation of the control arrangement 1 will now be described in more detail with reference to figure 5. The control arrangement 1 tracks the kite 6 automatically and the control arrangement 1 operates in an equilibrium state in which there is no overall moment applied to the arm 4 in a first plane or a second plane which is perpendicular to the first plane. The biasing arrangement 12 exerts a biasing force which is derived from the drive force F. The biasing control force applies a biasing moment to the arm 4 to cancel the moment applied to the arm 4 by the kite 6 in a first plane.

The moments applied to the arm 4 and the equilibrium state are calculated as follows with reference to figure 5: i) The height of the mast 3 is selected so that A is located at the centre of lateral resistance 14.

ii) Triangle ACE and triangle BCD are similar triangles: AE is always parallel to BD.

iii) When the lines pass around the mounting points the drive lines 7, 8 and the control lines 10, 11 run round a notionally frictionless pulley block, therefore the axial load in the drive lines 7, 8 and the control lines 10, 11 remains constant.

iv) The pivot point 5 is located at C. The arm 4 is able to rotate in the vertical plane relative to the mast 3.

v) Positive value moments cause the arm to rise. Now, taking moments about C: Moment applied to the arm: M = L F sin(e + p -c2) -(LI N) N F sin(6 -t) M = L F sin(e + p-cD)-L F sin(e-4) If p = 0 then F is aligned along AE and the line of action of the kite 6 pull passes through A, the centre of lateral resistance 14. The moment applied to the arm 4 is: M = L F sin(0 + 0-4)-L F sin(O-ø)= 0 This zero moment means that the arm 4 is in equilibrium. The arm 4 will remain in this position and the line of action 15 of the kite 6 will continue to pass through the centre of lateral resistance 14 until the kite 6 is flown to a different position.

If the kite 6 is flown higher then p > 0. Since (0 + p -CD) > (0-CD), then sin(9 + p -CD) > sin(G -CD) and so M > 0. The arm 4 therefore rises, causing B to increase and p to decrease until p = 0 and M = 0.

Equilibrium is thus regained.

If the kite 6 is flown lower then p cO. Since (B + p -CD) < (0 -0), then sin(B + p -CD) C sin(B -CD) and so M C 0. The arm 4 therefore falls, causing B to decrease and p to increase until p = 0 and M = 0.

Equilibrium is once again regained.

The theory described above illustrates how the control arrangement 1 operates to maintain the arm 4 in equilibrium in a first plane as the kite 6 moves up and down. The biasing arrangement 12 biases the mast 3 so that the line of action 15 always passes through the centre ot lateral resistance 14 as the kite 6 moves up and down in the first plane.

The mast 3 is free to rotate about the base unit which allows the control unit 1 to track the kite 6 as the kite 6 moves on plan relative to the boat 2. The control arrangement 1 tracks the movement of the kite 6 freely in the first and second planes without any external control or energy input. The control arrangement 1 therefore tracks the kite 6 automatically and maintains the arm 4 in equilibrium with the line of action 15 always extending through the centre of lateral resistance 14.

Since the control arrangement 1 ensures that the line of action 15 always aligns with and passes through the centre of lateral resistance 14, the kite 6 pulls the boat 2 forward without applying a heeling moment to the boat. Since there is no heeling moment applied to the boat, by comparison with a traditional sailing boat a narrower hull can be used and the ballast in the boat can be significantly reduced or omitted altogether. Nevertheless, some ballast may still be required for other reasons, for instance to make a boat self-righting from capsize.

The narrow hull and the reduction or total omission of ballast makes it possible to increase the length displacement ratio of a boat above 5.7. This allows the boat to travel at speeds corresponding to a Froude number greater than 0.45.

A boat powered by a kite attached to the control arrangement 1 can therefore travel at much higher speeds than an equivalent boat using a sail.

An embodiment of the present invention minimises or eliminates the heeling moment for a wind powered vehicle and therefore allows a narrower hull with less ballast to be used. When an embodiment of the invention is applied to a yacht this allows a length displacement ratio of greater than 5.7 to be achieved and the yacht is therefore able to exceed a speed of Fr = 0.45.

An additional benefit is derived from the vertical pull that the kite 6 exerts on the boat 2. The vertical pull exerts an upward lifting component on the boat 2 which further reduces the displacement of the hull in the water. The boat therefore sits higher in the water which increases the length displacement ratio and enables the boat to travel faster in the water.

The reduction in the heel of the boat by the control arrangement 1 minimises or eliminates the losses associated with travel in the water while heeling. The forward force on the boat 2 from the kite 6 is therefore maximised which further maximises the speed of travel in the water.

Further benefits derived from a narrow hull include minimising pitching due to waves and minimising the slamming impact of the water on the hull at speed.

This makes travelling in the boat more comfortable.

A narrow hull allows a high angle of vanishing stability and a small or zero negative area on the static stability curve. This improves the sea worthiness of the hull and improves safety.

A narrow hull also results in less roll due to waves which makes the boat more sea-worthy and comfortable. Less damping is required which results in less resistance and an increase in the speed of the boat.

The automatic tracking to achieve automatic equilibrium of the control arrangement 1 allows a very large kite to be fitted to a boat. The maximum size of the kite is limited by: i) The general requirement to avoid lifting the boat bodily out of the water.

U) If the control arrangement is located towards the stern of the boat the maximum kite size is limited by the requirement to avoid causing the boat to "pitchpole" when a boat is thrown stern over bows nto an nverted position.

Despite these constraints, a much larger kite area can be used than the maximum sail area for a sailing boat of equivalent size. This contributes to enabling the boat to achieve a significantly greater speed than a sailing boat of equivalent size.

Embodiments of the invention allow a boat to achieve a speed which is significantly higher than the maximum speed of a typical sailing boat of equivalent size.

Referring now to figure 6a of the accompanying drawings, a control arrangement 1 of a further embodiment of the invention incorporates the same mast 3 and arm 4 as the embodiment described above. However, in this further embodiment, the biasing arrangement 12 is formed by the drive lines 7, 8 and the control lines 10, 11 which extend between a third mounting point 19, a fourth mounting point 18 and a fixed point 21, with the third mounting point 19 and the fixed point 21 are at the base of the mast and the fourth mounting point 18 is positioned at the midpoint between the free end 9 and the pivot point 5, halfway along the length of the arm 4.

In this embodiment, the drive lines 7, 8 (only one of which is visible in figure 6a) and the control lines 10, 11 (not shown in figure 6a) extend slideably through a first mounting point 16 which is provided at or adjacent to the free end 9 of the arm 4. In other embodiments, the drive lines 7, 8 are joined together before reaching the arm 4 and a single drive line extends through the first mounting point 16.

The drive lines 7, 8 and the control lines 10, 11 extend slideably through a second mounting point 20 adjacent to the pivot 5. The drive lines 7, 8 and the control lines 10,11 extend downwardly from the second mounting point 20 to extend slideably through a third mounting point 19 positioned at the base of the mast 3 before extending to the fourth mounting point 18 positioned halfway along the length of the arm 4. The drive lines 7, 8 and the control lines 10, 11 extend slideably through the fourth mounting point 18 then double back from the fourth mounting point 18 to the fixing point 21 at the base of the mast 3.

In this further embodiment, the biasing arrangement 12 incorporates two loops of the drive lines 7, 8 and the control lines 10, 11 in order to match the midpoint mounting of the mounting point 18. This is in contrast with the embodiment described above where there are three loops of the drive lines 7, 8 and the control lines 10, 11 in the biasing arrangement 12 to match the one-third mounting point position of the mounting point 18. It is, however, to be appreciated that the control arrangement 1 operates in the same manner as the control arrangement 1 of the embodiments described above. The biasing arrangement 12 still biases the arm 4 to achieve equilibrium.

In this embodiment at each mounting point 16, 18, 19, and 20 a separate pulley is provided for the drive lines 7, 8 and for each of the control lines 10, 11. This allows the control lines to run through the pulleys independently of the drive lines.

The control arrangement 1 of a further embodiment of the invention will now be described in more detail with reference to figure 4b. In this embodiment, the drive lines 7, 8 (only one of which is visible in figure 4b) extend slideably through a first mounting point 16 which is provided at or adjacent to the free end 9 of the arm 4. In other embodiments, the drive lines 7, 8 are joined together before reaching the arm 4 and a single drive line extends through the first mounting point 16.

The drive lines 7, 8 extend along the length of the arm 4 and around a is rotatable element 17 which is provided at the pivot point 5. The rotatable element 17 is rotatably attached to either the arm 4 or the mast 3 or to the pivotal connection between the arm 4 and the mast 3. The drive lines 7, 8 are at least partly wound around the rotatable element 17. Friction between the rotatable element 17 and the drive lines 7, 8 ensures that the rotatable element 17 rotates as the drive lines 7, 8 move relative to the arm 4.

The drive lines 7, 8 extend around the rotatable element 17 and extend slideably through a second mounting point 18 provided on the arm 4 at a position substantially one-third of the way along the length of the arm 4 between the pivot point 5 and the free end 9. In this embodiment, the drive lines 7, 8 extend from the second mounting point 18 and extend slideably through a third mounting point 19 positioned at the base of the mast 3. The drive lines 7, 8 extend from the third mounting point 19 back up to the arm 4 and extend slideably through a fourth mounting point 20 provided on the arm 4 at approximately the same location as the second mounting point 18. The drive lines 7, 8 extend from the fourth mounting point 20 to a fixing point 21 at the base of the mast 3. In this embodiment, all of the mounting points are pulleys.

It is to be appreciated that portions of the drive lines 7, 8, the second, third and fourth mounting points 18-20 and the fixing points 21 all constitute components of the biasing arrangement 12. In this embodiment, the drive lines 7, 8 are looped three times between the mast 3 and the arm 4. The triple looping of the drive lines 7, 8 is selected to match the one-third distance position of the second mounting point 18 along the length of the arm 4. The triple loop of the biasing arrangement 1 exerts a control force between the mast 3 and the arm 4 which is three times the drive force F. The control arrangement 1 of a further embodiment of the invention will now be described in more detail with reference to figure 4c. In this embodiment, is the drive lines 7, 8 (only one of which is visible in figure 4c) extend slideably through a first mounting point 16 which is provided at or adjacent to the free end 9 of the arm 4. In other embodiments, the drive lines 7, 8 are joined together before reaching the arm 4 and a single drive line extends through the first mounting point 16.

The drive lines 7, 8 extend along the length of the arm 4 and around a rotatable element 17 which is provided at the pivot point 5. The rotatable element 17 is rotatably attached to either the arm 4 or the mast 3 or to the pivotal connection between the arm 4 and the mast 3. The drive lines 7, 8 are at least partly wound around the rotatable element 17. Friction between the rotatable element 17 and the drive lines 7, 8 ensures that the rotatable element 17 rotates as the drive lines 7, 8 move relative to the arm 4.

The drive lines 7, 8 extend around the rotatable element 17 and extend downwardly from the rotatable element 17. The drive lines 7,8 extend slideably through the second mounting point 22 at the base of the mast 3 before extending to the third mounting point 18 positioned one third of the way along the length ot the arm 4. The drive lines 7, 8 extend slidably through the third mounting point 18 before doubling back from the third mounting point 18 to a fourth mounting point 21 at the base of the mast 3. The drive lines extend slidably through the fourth mounting point 21 then return to the fixing point 20 adjacent to mounting point 18 on the arm 4. In this embodiment, all of the mounting points are pulleys.

It is to be appreciated that portions of the drive lines 7, 8, the second, third and fourth mounting points 18, 21, 22 and the fixing points 20 all constitute components of the biasing arrangement 12. In this embodiment, the drive lines 7, 8 are looped three times between the mast 3 and the arm 4. The triple looping of the drive lines 7, 8 is selected to match the one-third distance position of the second mounting point 18 along the length of the arm 4. The is triple loop of the biasing arrangement 1 exerts a control force between the mast 3 and the arm 4 which is three times the drive force F. Referring now to figure 6b of the accompanying drawings, a control arrangement 1 of a further embodiment of the invention incorporates the same mast 3 and arm 4 as the embodiment described above. However, in this further embodiment, the biasing arrangement 12 is formed by the drive lines 7, 8 which extend between a second mounting point 19, a third mounting point 18 and a fixed point 21, with the second mounting point 19 and the fixing point 21 located at the base of the mast and the third mounting point 18 positioned at the midpoint between the free end 9 and the pivot point 5, halfway along the length of the arm 4.

In this further embodiment, the drive lines 7, 8 extend downwardly from the rotatable element 17 to a mounting point 19 positioned at the base of the mast 3 the drive lines 7, 8 extend slideably past the second mounting point 19 before extending to the third mounting point 18 positioned halfway along the length of the arm 4. The drive lines 7, 8 extend slidably through the third mounting point 18 then double back to the fixing point 21 at the base of the mast 3.

In this further embodiment, the biasing arrangement 12 incorporates two loops of the drive lines 7, 8 in order to match the midpoint mounting of the mounting point 18. This is in contrast with the embodiment described above where there are three loops of the drive lines 7, 8 in the biasing arrangement 12 to match the one-third mounting point position of the mounting point 18. It is, however, to be appreciated that the control arrangement 1 operates in the same manner as the control arrangement 1 of the embodiments described above. The biasing arrangement 12 still biases the arm 4 to achieve equilibrium.

is Referring now to figure 6c of the accompanying drawings, a control arrangement 1 of a further embodiment of the invention incorporates the same mast 3 and arm 4 as the embodiment described above. However, in this further embodiment, the biasing arrangement 12 is formed by the drive lines 7, 8 which extend between a second mounting point 18 positioned at the midpoint between the free end 9 and the pivot point 5, halfway along the length of the arm 4, a third mounting point 19 positioned at the base of the mast and a fixed point 20 adjacent to the second mounting point 18.

In this further embodiment, the drive lines 7, 8 extend from the rotatable element 17 along the arm 4 to extend slideably through the second mounting point 18 before extending to extend slideably through the third mounting point 19. The drive lines 7, 8 double back from the third mounting point 19 to the fixing point 20 halfway along the arm 4.

In this further embodiment, the biasing arrangement 12 incorporates two loops of the drive lines 7, 8 in order to match the midpoint mounting of the second mounting point 18. It is to be appreciated that the control arrangement 1 operates in the same manner as the control arrangement 1 of the embodiments described above. The biasing arrangement 12 still biases the arm 4 to achieve equilibrium.

In other embodiments of the invention the biasing arrangement 12 is configured with a different position ratio to the one-third and one-half ratios described above. For instance, in one embodiment, the second mounting point 18 is positioned one-fifth of the way along the arm 4 and the drive lines 7, 8 are looped five times between the fixing point 21 and the arm 4. The biasing arrangement 12 may be organised so that the lines terminate at the foot of the mast or at the boom. Embodiments are possible for any case wherein the second mounting point is positioned on the second support member at substantially L I N of the distance between the free end and the pivot point, where L is the length of the second support member and N is a positive integer.

Kite control Referring now to Figures 8 to 10 of the accompanying drawings, the control lines 10, 11 extend slideably through the first mounting point 16 at the free end 9 of the arm 4 and along the length of the arm 4 to the rotatable element 17. The control lines 10, 11 are wound around respective ends of the rotatable element 17. In use, as the drive lines 7, 8 rotate the rotatable element 17 as the arm 4 moves up and down, the control lines 10, 11 extend and shorten by the same amount as the drive lines 7, 8 since the control lines 10, 11 are wound around the same rotatable element 17. The load in the control lines 10, 11 terminates on the rotatable element 17. The load in the control lines is delivered into the rotatable element 17 and from the rotatable element 17 by friction into the drive lines 7, 8 which are wound at least partly around the rotatable element 17.

After leaving the rotatable element 17, each control line 10, 11 is slideably connected respectively to the end of a flexible elongate crew line 23, 24. The crew lines 23, 24 can be pulled in or eased out by a user to vary the length of the control lines 10, 11 to control the kite 6.

The crew lines 23, 24 extend slideably through apertures 25, 26 provided in a lower section of the mast 3. The lower section of the mast 3 is rotatably mounted in a base unit 27. The crew lines 23, 24 pass through an aperture 28 in the base unit 27 to a crew member who may be positioned in a cockpit of the boat which is remote from the control arrangement 1.

The crew lines 23, 24 extend out from the base of the control unit 1 in substantial alignment with the longitudinal axis of the mast 3. This ensures is that the crew lines 23, 24 are kept close to one another which allows the crew lines 23, 24 to be uncrossed easily if the control arrangement 1 rotates such that the crew lines become crossed.

When the kite 6 is dead ahead of the boat 2, the crew lines 23, 24 are untwisted, as shown in figure 11 a. When the kite 6 moves to 60° off the bow of the boat 2, the control lines 23, 24 rotate with the mast 3 but remain untwisted, as shown in figure lib. If the kite 6 moves to 130° off the bow of the boat 2 and no action is taken regarding the control lines 23, 24 then the control lines 23, 24 cross with one another as shown in figure 11 c. In order to undo this twisting of the control lines 23, 24 a user uncrosses the control lines 23, 24, for instance by swapping the control lines 23, 24 between each hand. This uncrosses the control lines 23, 24 as shown in figure lid.

In a further embodiment, the control arrangement is as described above but with the control lines 10, ii taking the place of the crew lines 23, 24. After passing through the biasing arrangement 12, the control lines 10, 11 extend slideably through the mounting point at the base of the mast and extend slideably through apertures 25, 26 provided in a lower section of the mast 3.

Referring now to figure 12 of the accompanying drawings, a steering control arrangement 29 is connected to the crew lines 23, 24. In this embodiment, the steering control arrangement 29 incorporates a foot bar 30. The crew lines 23, 24 are connected to respective ends of the foot bar 30 after looping around pulleys 31, 32 which are fixed to the boat. The foot bar 30 incorporates a central aperture in an enlarged portion 33 through which the crew lines 23, 24 extend. A crew member 34 steers the kite 6 by moving the foot bar 30 with their feet. The foot bar 30 pulls the crew lines 23, 24 as it is pushed at each end by the feet of the crew member 34. The foot bar 30 is configured to rotate about the longitudinal length of the crew lines 23, 24 as shown by arrows 35 so that the crew member 34 can uncross the crew lines23,24.

Referring now to figure 13 of the accompanying drawings, in a further embodiment of the invention a foot bar 36 is attached to the crew lines 23, 24 so that a crew member 34 can control the crew lines 23, 24 with their feet.

However, in this embodiment an anchor line 37 is attached to the centre of the foot bar 36 and to a mounting point 38 provided on the boat. In this embodiment, the anchor line 37 takes up the majority of the load in the crew lines 23, 24 so that the crew member 34 only has to exert a minimal effort on the foot bar 36 in order to steer the kite 6. In this embodiment the angle of incidence of the kite 6 to the wind is controlled by drawing the anchor line 37 through the cleat 38.

Referring to Figure 29 of the accompanying drawings, the crew lines 23, 24 extend in one embodiment of the invention from a control arrangement 1 mounted at the stern of a boat. The crew lines 23, 24 loop around respective pulleys 53, 54. The pulleys 53, 54 are mounted on elongate swivel bar 56, as shown in Figure 29. The swivel bar 56 is pivotally mounted to the boat to pivot about a central pivot point 57. In use, an occupant 55 of the boat holds one crew line 23, 24 in each hand and controls the kite 6 by pulling and releasing each crew line 23, 24. The crew lines 23, 24 and the swivel bar 56 are configured to rotate about the longitudinal length of the crew lines 23, 24 as shown by arrows 35 so that the crew member 55 can uncross the crew lines 23, 24.

In a further embodiment of the invention, the crew lines 23, 24 are attached to an elongate power bar 56, as shown in Figure 30. The power bar 56 is pivotally mounted to the boat to pivot about a central pivot point 57. In this embodiment, the pivot point 57 is an attachment to an adjustable tension line 58. The tension line 58 extends from the power bar 56, to pass slideably around one or more junction points 59, 60 to an adjustable cleat 61. In this embodiment, to adjust the angle of incidence of the kite to the wind the position of the power bar 56 may be altered by adjusting the attachment position of the tension line 58 on the cleat 61. In use, a user 55 holds further crew lines 62, 63 attached to each end of the power bar 56. In this embodiment, the length and orientation of the power bar 56 may be selected to increase or decrease the sensitivity of the steering arrangement. For instance, the length of the power bar 56 may be increased to enable a user 55 to steer the kite by only applying minimal movement to the further crew lines 62, 63. The crew lines 23, 24 and the power bar 56 and the further crew lines 62, 63 are configured to rotate about the longitudinal length of the crew lines 23, 24 as shown by arrows 35 so that the crew member 55 can uncross the crew lines 23, 24.

In a further embodiment, the power bar 56 is positioned to allow the user 55 to move the power bar 56 with their feet and legs. In this further embodiment, the user 55 can steer the kite using their feet and legs whilst keeping their hands free for other purposes. To adjust the angle of incidence of the kite to the wind the position of the foot operated power bar 56 can be adjusted by adjusting the length of the tension line 58.

In other embodiments, the arrangement does not incorporate a foot bar. In these arrangements, the crew lines 23, 24 may be pulled and released by a crew member holding onto the crew lines 23, 24. In further embodiments, the crew lines 23, 24 are connected to a hand bar which may be held by a crew member and moved to control the kite 6. The hand bar may be of a type usually used for kite surfing.

Where the control lines continue through the base of the mast, the control lines 10, 11 may be pulled and released by a crew member holding onto the control lines 10, 11. In further embodiments, the control lines 10, 11 are connected to a hand bar or a foot bar which may be moved by a crew member to control the kite 6. The hand bar may be of a type usually used for kite surfing.

For all the arrangements described above the crew lines 23, 24 or the control lines 10, 11 may be controlled by a mechanical, electronic or hydraulic system in place of the foot or hand arrangements described above. This will allow any mechanical, electronic or hydraulic system to be located in a location where safe and easy access is available for maintenance.

Fine tuning heeling moments Referring now to figure 14 of the accompanying drawings, in one embodiment of the invention the fixing point 21 is moveable vertically from the base of the mast 3 by a distance +1-0. In this embodiment, the second mounting point 18 is positioned halfway along the length of the arm 4 and so movement of the fixing point 21 by a distance 0 results in the line of action 15 moving in the same direction by a distance 20.

The movement of the fixing point 21 moves the line of action 15 so that the line of action 15 does not pass through the centre of lateral resistance 14 and so the control arrangement 1 exerts a heeling moment on the boat 2 when the control arrangement 1 is in equilibrium. The heeling of the boat can therefore be tuned by moving the fixing point 21. This may be necessary to finely tune the control arrangement 1 to take into account slight variations in the position of the centre of lateral resistance 14 when the boat 2 is travelling at different speeds or in different sea conditions. The movement at fixing point 21 may be made manually, or by mechanical, electronic or hydraulic means.

In further embodiments of the invention movement of the fixing point 21 by a distance 0 results in the line of action 15 moving in the same direction by a distance NO where N is a positive integer and corresponds to the number of is loops in the biasing arrangement 12.

Referring now to figure 15 of the accompanying drawings, in a further embodiment the drive lines 6, 7 are fixed to fixing point 21 which is free to travel vertically on the mast 3. The fixing point 21 is connected to a tuning line 39. The tuning line 39 extends slideably through the aperture in the base unit to an adjustable cleat 40 which is fixed to the boat. The length of the tuning line may be adjusted by fixing the tuning line 39 at different positions in the cleat in order to tune the heeling moment applied by the control arrangement 1 to the boat 2. In this embodiment, the crew lines 23, 24 are positioned on either side of the tuning line 39 and arranged to rotate around the tuning line 39. The tuning line 39 may be adjusted manually, or by mechanical, electronic or hydraulic means.

Referring now to figure 16 of the accompanying drawings, the embodiment shown in figure 15 may be modified to a yet further embodiment which incorporates a foot bar 41 which is connected to the crew lines 23, 24. In this embodiment, the tuning line 39 extends through an aperture in the centre of the foot bar 41 to the cleat 40. This embodiment combines the foot control features of the foot bar 41 with the tuning line 39. The tuning line 39 may be adjusted manually, or by mechanical, electronic or hydraulic means.

Roll stabilisation In further embodiments of the invention, the control arrangement 1 incorporates a motor which controls the fine tuning of the heeling moment.

The motor is configured to automatically adjust the heeling moment applied by the control arrangement 1 to the boat 2 in order to counteract any roll of the boat 2. The motor can therefore be used to actively stabilise the boat 2. If multiple anchors are used to hold the boat in position this can also be used to stabilise a boat that is anchored.

The motor may be mounted at the foot of the mast or on the hull of the boat to control a tuning line 39. Alternatively the motor may be mounted on the arm 4 to adjust the location of the mounting points of the biasing arrangement 12 on the arm 4, this has the same effect as adjusting the height of the mounting points at the foot of the mast.

Adjusting the line lengths, launching and retrieving the kite or aerofoil In an arrangement similar to that shown in figure 15 of the accompanying drawings in one embodiment of the invention the drive lines 7, 8 extend through the base of the mast The drive lines 7, 8 extend through the aperture in the base unit to an adjustable cleat 40 which is fixed to the boat. The length of the drive lines 7, 8 may be adjusted by fixing the drive lines 7, 8 at different positions in the cleat in order to move the kite 6 closer to or further from the boat 2. In this embodiment, the crew lines 23, 24 are positioned on either side of the drive lines 7, 8 and arranged to rotate around the drive lines 7, 8. The drive lines 7, 8 may be adjusted manually, or by mechanical, electronic or hydraulic means.

In this embodiment, the control lines 10, 11 are wrapped around the rotatable element 17 as the drive lines 7, 8 are wound onto the drum 42. All of the lines may therefore be wound in together to bring in the kite 6.

In a further embodiment of the invention the drive lines 7, 8 extend through the base of the mast The drive lines 7, 8 extend through the aperture in the base unit to an adjustable cleat 40 which is fixed to the boat. The length of the drive lines 7, 8 may be adjusted by fixing the drive lines 7, 8 at different positions in the cleat is in order to move the kite 6 closer to or further from the boat 2. In this embodiment, the control lines 10, 11 are positioned on either side of the drive lines 7, 8 and arranged to rotate around the drive lines 7, 8. The drive lines 7, 8 may be adjusted manually, or by mechanical, electronic or hydraulic means.

In this embodiment, the length of the control lines 10, 11 must be adjusted as the length of the drive lines 7, 8 are adjusted.

Referring now to figure 17 of the accompanying drawings, in one embodiment of the invention the drive lines 7, 8 are wound around a drum 42. The drum 42 winds in the drive lines 7, 8 to bring in the kite 6. In this embodiment, the control lines 10, 11 are wrapped around the rotatable element 17 as the drive lines 7, 8 are wound onto the drum 42. All of the lines may therefore be wound in together to bring in the kite 6.

In a further embodiment, the drum 42 is positioned on the arm 4. This embodiment operates as described above, but with the drum 42 located on the arm 4 for use when the drive lines 7, 8 terminate on the arm 4.

Referring to Figure 31 of the accompanying drawings, a further embodiment of the invention incorporates a wind powered drive element in the form of a collapsible wing 64. The collapsible wing 64 is attached to a control arrangement 1 of the type described above by drive lines 7, 8 and control lines 10,11.

The wing in this embodiment is collapsible but it is to be appreciated that further embodiments of the invention incorporate a wing or another wind powered element with an aerofoil section which is either fixed or collapsible.

is Referring to Figures 32 and 33 of the accompanying drawings, the wing 64 may be similar to the type typically used for hang-gliding. The wing 64 incorporates two elongate leading edge struts 65, 66 which are attached to struts 72, 73. The struts are pivotally connected to one another at one end G by a pivotal connection. In this embodiment a flexible elongate element 67 is used to draw the ends of the leading edge struts 65, 66 together and thus open the wing. A flexible elongate element 74 connects the outer ends of the leading edge struts 65, 66. The struts 65, 66 are held in sleeves 68, 69 which are sewn in a substantially triangular sheet of flexible material 70. The flexible material 70 extends between the struts 65, 66 and the flexile elongate cable element 74 to define a typical wing shape. When the wing is opened the fabric material 70 is drawn taut between the leading edge struts 65, 66 and the elongate cable element 74.

The wing 64 incorporates a float element 71 which is generally fin-shaped to reduce air resistance when the wing is in flight. The float element 71 is attached to one of the leading edge struts 65 and to support struts 72, 73 which extend from the float element 71 to a connection with a respective one of the leading struts 65, 66.

The float element 71 is configured to float on water, as shown in Figure 34.

The float element 71 is positioned near the front of the wing 64 so that the front of the wing 64 floats out of the water, as shown in Figure 34. This ensures that the wing 64 floats with the flexible sheet 70 held at an angle of incidence to the wind which makes it possible to re-launch the wing 64 if the wing 64 lands on water. The top and bottom surfaces of the wing and float may have identical geometry so that it makes no difference which way up the wing is flown, nor does the way up affect the relaunch capacity.

Referring now to Figures 35a-35c, the wing 34 is assembled on the deck of a boat by: is i) Drawing the fabric sleeves 68, 69 over the leading edge struts 65, 66 and fixing the corners of the sleeves to the ends of the leading edge struts 65, 66 and to one another (on the back edge of the wing) as shown in figure 35b.

ii) Connecting the drive lines and the control lines to the wing.

iii) If necessary moving the closed wing forward along the deck so that the wing is forward of the end of the arm 4 as shown in figure 35c.

iv) Pivoting the struts 65, 66 about their pivotal connection G to open the flexible sheet 70 as shown in Figure 36.

v) The wing 34 can then be launched from the deck of the boat with the drive lines 7, 8 and the control lines 10, 11 connecting the wing 64 to the control arrangement 1. Once in the air, it is to be appreciated that the wing 64 flies in a similar manner to the kite 6 described above. The control arrangement 1 automatically tracks the movement of the wing 64 without the need for any external control or energy input.

Throughout the launching process the boat is orientated so that the wind is directed on the stern of the boat. This places the wind on the leading edge of the wing.

The process is reversed for retrieving the wing to the boat.

A similar process to the one described above may be adopted for launching and retrieving a kite, rigid wing or other wind power device.

Mounting the control arrangement on a kayak or canoe Referring to figure 18 of the accompanying drawings, in one embodiment the base unit of the control unit 1 is mounted to a centreboard 43 which is configured to be attached to a boat. The centreboard 43 is also known as a is keel. The centreboard 43 incorporates a planar top section 44 with two centreboard sections 45, 46 projecting downwardly from each end. The centreboard 43 is mounted to a boat such as a kayak 47 by placing the centreboard 43 over the kayak 47 with the centreboard sections 45, 46 extending downwardly on each side of the kayak 47. A boat which does not normally have a centreboard can thus be adapted to incorporate a centreboard along with a control arrangement 1 of an embodiment of the invention so that the boat can be powered by a wind powered element such as a kite.

Location of the control arrangement on the boat At speeds corresponding to a Froude number of up to around 0.45 a hull operates in the displacement mode.

For hulls operating in the displacement mode the control arrangement 1 can be located at any point along the length of the hull. It may be most practical to locate the control arrangement 1 on the bow of the vessel, this will provide the maximum area free from rigging and minimise the risk of the arm 4 sweeping across the deck.

A keel or centreboard will be required below control arrangement 1 to resist lateral loads.

At speeds corresponding to Froude numbers above about 0.45 a hull starts gain some support from hydrodynarnic lift and the hull begins to plane.

The location of the control arrangement 1 on a boat is important if the boat is to plane. If the control arrangement is located correctly, resistance is minimised and the hull is able to plane. If the control arrangement is located incorrectly resistance is high and it is very difficult to provide sufficient power for the hull to plane.

i) Theory of planing hulls As a boat travels through water, water is moved to make way for the hull. In order to be moved, the water must be accelerated to have a velocity and momentum. A force must be applied to accelerate the water and an equal and opposite force is applied to the hull. At high speed and with suitable hull geometry this hydrodynamic force can be sufficient to support the boat. When this happens the boat is planing.

The vertical component of the force applied to the hull is referred to as the hydrodynamic lift, the horizontal component of the force is referred to as the hydrodynamic resistance or hydrodynamic drag.

As the trim angle increases the hydrodynamic lift increases, the hydrodynamic resistance increases, and the frictional resistance of water on the hull becomes less significant since the wetted area reduces. At low trim angles frictional resistance dominates, at high trim angles hydrodynamic resistance dominates. There is a trim angle where the total resistance is a minimum, generally this occurs at a trim angle of around 4 degrees.

ii) Analysis of planing motorboats It is usual to take moments about the point where the vectors representing the propeller thrust and the hydrodynarnic lift intersect. To establish the trim angle and power required the moments due to water resistance on the hull and appendages must be balanced by the moments due to the self weight of the vessel. This principle is illustrated in figure 19.

iii) Analysis of a planing hull with an embodiment of the invention The same theory is suitable for analysis of a planing boat using an embodiment of the invention. In this case, moments are taken about the point where the vectors representing the kite force and the hydrodynamic lift intersect. This point varies as the hydrodynamic lift varies, but also as the kite moves relative to the hull.

To establish the trim angle and kite force required, the moments due to water resistance on the hull and appendages must be balanced by the moments due to the self weight of the vessel. In order for equilibrium to be achieved the intersection between the vectors representing the kite force and the hydrodynamic lift must be either: ABOVE the resistance vector and AHEAD of the self weight vector "Above & Ahead" as illustrated in figure 20, or BELOW the resistance vector and BEHIND the self weight vector "Below & Behind" as illustrated in figure 21.

If the intersection point is "Below and Ahead", the hull trim will increase and the hydrodynamic resistance will increase. If the kite provides sufficient power the speed and or trim will increase and the hydrodynamic lift vector will move backwards until the intersection point is "Below and Behind", however the high trim angle results in high resistance. While the intersection point remains "Below and Ahead" it will not be possible to achieve equilibrium and plane.

Trim tabs could be added at the stern of the vessel to introduce lift at the stern and move the hydrodynamic lift vector towards the rear of the hull.

If the intersection point is "Above and Behind" the hull trim will decrease and the vessel will tend to bury the bow in the water. If the bow section provides sufficient lift the trim will decrease and the hydrodynamic lift vector will move forward until the intersection point is "Above and Ahead" While the intersection point remains "Above and Behind" it will not be possible to achieve equilibrium and plane. To reduce resistance in waves the bow tends to have a fine narrow profile which provides little hydrodynamic lift. A hydrofoil or trim tabs can be added at the bow of the vessel to introduce lift at the bow and move the hydrodynamic lift vector towards the bow.

Control arrangement 1 located forward of the centre of mass: This principle is illustrated in figure 22. If the control arrangement 1 is placed near the bow of the vessel the lever arm on the resistance vector is large, in order to achieve equilibrium the hydrodynamic lift vector must be far behind the self weight vector. This is generally only possible at very high speed.

A centreboard or keel will be required below the control arrangement 1 to resist lateral loads. If the vessel does manage to plane, the trim will be large and the centreboard or keel will be wholly or partly lifted out of the water, this will alter the position of the centre of lateral resistance.

The kite force will therefore no longer pass through the centre of lateral resistance and a rolling moment will be applied to the hull.

Locating the control arrangement 1 ahead of the centre of mass makes it very difficult to achieve the plane and is therefore not a suitable geometry for a vessel intended to plane.

Control arrangement 1 located near the centre of mass: This principle is illustrated in figure 23. If the control arrangement 1 is placed near the centre of mass there are combinations of speed and inclination of the kite lines for which the intersection is "Below and Ahead" the hull trim will increase and the hydrodynamic resistance will increase. The boat will encounter this combination of speed and lines inclination before planing is achieved. If the kite provides sufficient power the speed and or trim will increase and the hydrodynamic lift vector will move backwards until the intersection point is "Below and Behind", however the high trim angle results in high resistance. While the intersection point remains "Below and Ahead" it will not be possible to achieve equilibrium and plane.

Trim tabs could be added at the stern of the vessel to introduce lift at the stern and move the hydrodynamic lift vector towards the rear of the hull. Otherwise the vessel will "porpoise" pitching back and forth until sufficient speed has been achieved for the hydrodynamic lift to move sufficiently far back on the hull to place the intersection point "Below and Behind" and for planing equilibrium to be achieved. However, "porpoising" is not energy efficient and it will be difficult to move through this zone to pick up sufficient speed to achieve a steady plane. Note that trim tabs at the rear require an active control system to manage the tab action as the bow lifts.

A centreboard or keel will be required below the control arrangement 1 to resist lateral loads. If the vessel achieves equilibrium at a high trim angle and the centreboard or keel will be partly lifted out of the water, this will alter the position of the centre of lateral resistance. The kite force will therefore no longer pass through the centre of lateral resistance and a rolling moment will be applied to the hull.

Locating the control arrangement 1 near the centre of mass makes it difficult to achieve planing and is therefore not an optimal arrangement for a vessel intended to plane.

Control arrangement 1 located slightly to the rear of the centre of mass: This principle is illustrated in figure 24. If the control arrangement 1 is placed slightly to the rear the centre of mass there are: Combinations of speed and inclination of the kite lines for which the Intersection is "Below and Ahead", the analysis of this case is as described above.

Combinations of speed and inclination of the kite lines for which the intersection is "Above & Behind", in this area the bow will lower. Trim tabs at the bow will be required to control this effect.

The trim tabs can be passively controlled to increase lift as the bow descends. A hydrofoil located at the bow would not be suitable to control the bow down trim as this would aggravate the case when the intersection point is "Below and Ahead".

The boat may encounter either or both of these conditions before planing is achieved.

The need for trim tabs at the bow and stern makes this arrangement particularly complicated.

A centreboard or keel will be required below the control arrangement 1 to resist lateral loads. If the vessel achieves equilibrium at a high trim angle and the centreboard or keel may be partly lifted out of the water, this would alter the position of the centre of lateral resistance. The kite force would therefore no longer pass through the centre of lateral resistance and a rolling moment will be applied to the hull.

Control arrangement 1 well behind the centre of mass: This principle is illustrated in figure 25. If the control arrangement 1 is placed well behind the centre of mass there are combinations of speed and inclination of the kite lines for which the intersection point is "Above and Behind". If the geometry is selected correctly, there is no case when the intersection point is "Below and Ahead". When the intersection is "Above and Behind" the trim will reduce lowering the bow towards the water surface.

The bow down trim effect can be most effectively controlled using a dihedral hydrofoil located below the bow. The level of the hydrofoil can be selected so that it sets the trim of the hull at the angle of minimum resistance.

At low speed the hydrofoil is fully submerged as illustrated in figure 26a.

Note that at low speed the transom may be above the water surface, this reduces resistance at low speed.

As the speed approaches Fr = 0.45 the lift generated by the hydrofoil increases the trim of the boat towards 4 degrees making it possible for the boat to start planing at a lower speed than would otherwise be the case. Since a dihedral hydrofoil is used, as the speed increases and the boat starts to plane the hydrofoil is partly exposed from the water, this is illustrated in figure 26b. This provides additional lift capacity to counteract any bow down trim: if the bow is lowered the wings of the hydrofoil are immersed to greater depth and the lift increases. The lift from the hydrofoil raises the bow and controls the trim angle of the hull, this ensures that a trim angle of approximately 4 degrees is maintained, minimising resistance.

A hydrofoil is a very efficient form of support for a boat, a hydrofoil supports a boat with less drag than is the case for a planing vessel.

The bow down moment from the kite transfers load on to the hydrofoil and off the planing hull, this further reduces resistance.

At high speed the hydrofoil planes on the water surface, in effect the hull operates as if it was a stepped planing hull. The level of the hydrofoil relative to the hull is selected so that the vessel maintains a trim angle of about 4 degrees to minimise resistance. Any bow down trim lowers the hydrofoil slightly into the water resulting in significant lift generation which offset the bow down trim. Since a dihedral foil is used the pounding effect in waves is limited, in the same way that a deep V hull limits the pounding effect.

Alternatively trim tabs at the bow could be used to offset the bow down moment. Trim tabs will not be as efficient as a hydrofoil, particularly at lower speeds.

Since the control arrangement 1 is near the stern the rudder and centreboard/keel can be combined in a single element.

Total resistance is lower due to a single rudder-keel than for two separate elements.

Since the rudder-keel is near the stern of the vessel it will not be lifted out of the water as the trim angle increases, the performance of the control arrangement 1 in minimising heeling moments will not be compromised as the trim of the boat varies.

The rudder-keel can be rotated, this allows the angle of incidence of the rudder-keel to be adjusted so that the lateral load from the kite is balanced by the rudder-keel, and there is no requirement for leeway of the entire vessel to generate lateral loads on a fixed centreboard or keel: Leeway can be eliminated.

Since leeway is avoided the hull will travel through the water along the axis of the hull, this further reduces resistance.

Since leeway is avoided a deep V hull form can be adopted without increasing resistance due to vortex shedding as water flows across the hull. The deep V hull form improves course keeping in heavy seas, and also reduces pounding in waves.

Based on the above assessment, the optimum location for the control arrangement 1 is located well behind the centre of mass, towards the stern of the boat.

Referring now to figure 27 of the accompanying drawings, in a further embodiment of the invention, the mast 3 of the control arrangement 1 is connected to a control element to be attached to a boat. In one embodiment, the control element is a control element which provides the function of both a rudder and a keel/centreboard.

A combined rudder-keel of an embodiment of the invention may be mounted to a standard hull designed to take an outboard motor. The combined rudder-keel incorporating the control arrangement 1 may be fixed to the transom, in is place of an outboard motor.

An example of an optimum design is shown in Figure 27 in which a control arrangement 1 of an embodiment of the invention is mounted at the stern of a boat 48 with a hydrofoil at the bow.

Figure 28 shows a pair of trim tabs 49, 50 which are attached at either end of a support beam 51. The support beam 51 is pivotally mounted to a hull 52.

The arrangement is configured so that the trim tabs 49, 50 may be raised or lowered by rotating the support beam 51 relative to the hull 52. The trim tabs 49, 50 provide additional lift to prevent immersion of the bow of the hull 52.

The trim tabs 49, 50 can be raised to prevent the trim tabs 49, 50 providing unnecessary resistance at low speeds.

In one embodiment, the trim tab arrangement is fitted with a damping system which in the form of a resilient element or spring which allows the trim tabs 49, to move against a resilient bias. The resilient bias of the trim tabs 49, 50 reduces the pounding effect of the waves on the hull 52.

It is to be appreciated that a control arrangement 1 of an embodiment of the invention may be used with any type of watercraft including, but not limited to: a surfboard, raft, kayak, canoe, dinghy, yacht or ship, whether monohull or multihull, displacement, planing or hydrofoil.

Whilst embodiments described above have been for use on a boat, it is to be appreciated that embodiments of the invention may be installed on a land snow or ice based wind powered vehicle. A typical land, snow or ice based wind powered vehicle sits on wheels, skis or a sledge. In these land, snow or ice based embodiments, the centre of lateral resistance is where the wheels, skis or sledge contact the surface on which they are resting. It is to be appreciated that control arrangements of embodiments of the invention used on land, snow or ice based wind powered vehicles operate in the same manner as described above to enable the control arrangement 1 to automatically track a wind powered element without the need for any external energy input to control the arrangement.

When used in this specification and claims, the terms "comprises" and "comprising" and variations thereof mean that the specified features, steps or integers are included. The terms are not to be interpreted to exclude the presence of other features, steps or components.

Claims

Claims 1. A control arrangement for a wind powered vehicle, the arrangement comprising: a first elongate support member, a second elongate support member which is pivotally mounted at a pivot point to the first support member, the second support member having a free end which is remote from the pivot point, a flexible elongate drive line which is attachable at one end to a wind powered drive element which, in use, applies a drive force to the drive line, wherein the drive line extends slideably through a first mounting point adjacent the free end of the second support member such that the drive force applies a first moment to the second support member about the pivot point, a biasing arrangement configured to convert the drive force into a is biasing force and to apply the biasing force to the second support member at a point between the free end and the pivot point, the biasing force applying a second moment to the second support member which at least partly cancels the first moment to reduce the overall moment to the second support member in a first plane, and a base unit which is rotatably attached to the first support member, the first support member being rotatable by any number of 36O rotations or part rotations relative to the base unit and configured to rotate relative to the base unit until the second support member aligns with the drive force and no overall moment is applied in a second plane to the second support member.
2. A control arrangement according to claim 1, wherein the biasing arrangement comprises a second mounting point which is provided on the second support member between the free end and the pivot point, the biasing arrangement further comprising a fixing point provided on the first support member, the drive line extending slideably through the second mounting point and being fixed to the first support member at the fixing point.
3. A control arrangement according to claim 2, wherein the drive line extends a plurality of times between the second mounting point and the fixing point.
4. A control arrangement according to claim 2 or claim 3, wherein the second mounting point is positioned substantially half way between the free end and the pivot point.
5. A control arrangement according to claim 4 as dependent on claim 3, wherein the drive line extends twice between the second mounting point and the fixing point.
6. A control arrangement according to claim 2 or claim 3, wherein the second mounting point is positioned on the second support member at substantially one third of the distance between the free end and the pivot point.
7. A control arrangement according to claim 6 as dependent on claim 3, wherein the drive line extends three times between the second mounting point and the fixing point.
8. A control arrangement according to any one of the preceding claims, wherein the drive line extends at least partly around a rotatable element which is provided at the pivot point.
9. A control arrangement according to any one of the preceding claims, wherein the arrangement further comprises two flexible elongate control lines which are attachable at one end to the wind powered drive element to control the wind powered drive element.
10. A control arrangement according to claim 9 as dependent on claim 8, wherein the control lines extend at least partly around the rotatable element.
11. A control arrangement according to claim 10, wherein the control lines and the drive lines wind onto or reel out from the rotatable element as the rotatable element rotates.
12. A control arrangement according to any one of the preceding claims, wherein the base unit incorporates an aperture and the elongate axis of the first support member is at least partly aligned with the aperture in the base unit.
13. A control arrangement according to claim 12 as dependent on any one of claims 9 to 11, wherein the control lines extend through the aperture in the base unit.
14. A control arrangement according to claim 12 as dependent on any one of claims 9 to 11, wherein the arrangement further comprises two crew lines which are connected respectively to the two control lines, the crew lines extending through the aperture in the base unit.
15. A control arrangement according to any one of claims 9 to 14, wherein the control lines or the crew lines are configured to be pulled in or let out manually by a user.
16. A control arrangement according to claim 15, wherein the control lines or the crew lines are connected to a power bar which is operable to be controlled by the hands of a user.
17. A control arrangement according to claim 15, wherein the control lines or the crew lines are attached to a foot bar which is operable to be controlled by the user's feet.
18. A control arrangement according to any one of claims 9 to 14, wherein the control lines or the crew lines are connected to a mechanical control arrangement.
19. A control arrangement according to claim 2, wherein the fixing point is moveable to adjust a heeling moment applied by the control arrangement.
20. A control arrangement according to claim 19, wherein the arrangement further comprises an arrangement for adjusting the position of the fixing point automatically to stabilise the control arrangement if the control arrangement is subjected to a rolling moment.
21. A control arrangement according to any one of the preceding claims, is wherein each of the lines is releasably attached to an attachment element and wherein the length of the lines is adjustable by winding in or letting out the lines from the releasable attachment.
22. A control arrangement according to claim 21, wherein the releasable attachment is a rotatable drum which is operable to rotate to wind in or let out the lines.
23. A control arrangement according to any one of the preceding claims, wherein the arrangement further comprises a wind powered element which is connected to one end of each line.
24. A control arrangement according to claim 23, wherein the wind powered element comprises an aerofoil section.
25. A control arrangement according to claim 24, wherein the wind powered element is a kite.
26. A control arrangement according to claim 24, wherein the wind powered element is a wing.
27. A control arrangement according to claim 25, wherein the wing is collapsible.
28. A control arrangement according to any one of claims 23 to 27, wherein the wind powered element incorporates a float arrangement which floats on water.
29. A control arrangement according to any one of the preceding claims, is wherein the base unit is mounted to a watercraft.
30. A control arrangement according to claim 29, wherein the watercraft comprises a keel, centreboard or a single element comprising both a keel/centreboard and rudder to resist lateral movement of the boat.
31. A control arrangement according to claim 30, wherein the longitudinal axis of the first support member is aligned with the longitudinal axis of the keel or centreboard.
32. A control arrangement according to claim 31, wherein the length of the second support member is selected so that the direction of the force exerted by the wind powered element on the drive line extends substantially through the centre of lateral resistance of the combined hull, keel or centreboard, rudder and other appendages when there is no overall moment applied to the second support member in the first or second planes.
33. A control arrangement according to any one of claims 1 to 28, wherein the base unit is mounted to a land based wind powered vehicle.
34. A control arrangement according to any one of claims 1 to 28, wherein the base unit is mounted to a snow or ice based wind powered vehicle.
35. A control arrangement according to any one of claims 1 to 28, wherein the base unit is configured to be attached to a boat.
36. A control arrangement according to claim 35, wherein the base unit is attached directly to a keel or centreboard which is configured to be attached to a boat.
37. A control arrangement according to claim 35, wherein the base unit is attached directly to a rudder which is configured to be mounted to a boat.
38. A control arrangement according to claim 37, wherein the rudder is mounted to a boat which does not incorporate of keel or centreboard.
39. A control arrangement according to claim 37 or claim 38, wherein the rudder is pivotally mounted to or near the rear of a boat.
40. A control arrangement according to any one of claims 35 to 39, wherein the base unit is attached to a boat.
41. A control arrangement according to any one of claims 35 to 40, wherein the boat is a kayak.
42. A control arrangement according to any one of claims 35 to 40, wherein the boat is a dinghy.
43. A control arrangement according to any one of claims 35 to 40, wherein the boat is a yacht.
44. A control arrangement according to any one of claims 35 to 41 wherein the boat is a boat selected from a group consisting of a raft, surfboard, ship, canoe, monohull, multihull, displacement vessel, planing vessel or a vessel supported on hydrofoils.
45. A control arrangement according to claim 44, wherein the control arrangement is mounted to a planing vessel at or near the rear of the planing vessel.
46. A control arrangement according to any one of claims 35 to 45, wherein the boat comprises at least one hydrofoil element.
47. A control arrangement substantially as herein before described with reference to and as shown in any one of the accompanying drawings.
48. Any novel feature or combination of features disclosed herein.Amendments to the Claims have been filed as follows Claims 1. A control arrangement for a wind powered vehicle, the arrangement comprising: a first elongate support member, a second elongate support member which is pivotally mounted at a pivot point to the first support member, the second support member having a free end which is remote from the pivot point, a flexible elongate drive line which is attachable at one end to a wind powered drive element which, in use, applies a drive force to the drive line, wherein the drive line extends slideably through a first mounting point adjacent the free end of the second support member such that the drive force applies a first moment to the second support member about the pivot point, a biasing arrangement configured to convert the drive force into a is biasing force and to apply the biasing force to the second support member at a point between the free end and the pivot point, the biasing force applying a second moment to the second support member which at least partly cancels the first moment to reduce the overall moment to the second support member in a first plane, and a base unit which is rotatably attached to the first support member, the first support member being rotatable by any number of 36O rotations or part rotations relative to the base unit and configured to rotate relative to the base unit until the second support member aligns with the drive force and no overall moment is applied in a second plane to the second support member.2. A control arrangement according to claim 1, wherein the biasing arrangement comprises a second mounting point which is provided on the second support member between the free end and the pivot point, the biasing arrangement further comprising a fixing point provided on the first support member, the drive line extending slideably through the second mounting point and being fixed to the first support member at the fixing point.3. A control arrangement according to claim 2, wherein the drive line extends a plurality of times between the second mounting point and the fixing point.4. A control arrangement according to claim 2 or claim 3, wherein the second mounting point is positioned substantially half way between the free end and the pivot point.5. A control arrangement according to claim 4 as dependent on claim 3, wherein the drive line extends twice between the second mounting point and the fixing point.6. A control arrangement according to claim 2 or claim 3, wherein the second mounting point is positioned on the second support member at substantially one third of the distance between the free end and the pivot point.7. A control arrangement according to claim 6 as dependent on claim 3, wherein the drive line extends three times between the second mounting point and the fixing point.8. A control arrangement according to any one of the preceding claims, wherein the drive line extends at least partly around a rotatable element which is provided at the pivot point.9. A control arrangement according to any one of the preceding claims, wherein the arrangement further comprises two flexible elongate control lines which are attachable at one end to the wind powered drive element to control the wind powered drive element.10. A control arrangement according to claim 9 as dependent on claim 8, wherein the control lines extend at least partly around the rotatable element.11. A control arrangement according to claim 10, wherein the control lines and the drive lines wind onto or reel out from the rotatable element as the rotatable element rotates.12. A control arrangement according to any one of the preceding claims, wherein the base unit incorporates an aperture and the elongate axis of the first support member is at least partly aligned with the aperture in the base unit.13. A control arrangement according to claim 12 as dependent on any one of claims 9 to 11, wherein the control lines extend through the aperture in the base unit.14. A control arrangement according to claim 12 as dependent on any one of claims 9 to 11, wherein the arrangement further comprises two crew lines which are connected respectively to the two control lines, the crew lines extending through the aperture in the base unit.15. A control arrangement according to any one of claims 9 to 14, wherein the control lines or the crew lines are configured to be pulled in or let out manually by a user.16. A control arrangement according to claim 15, wherein the control lines or the crew lines are connected to a power bar which is operable to be controlled by the hands of a user.17. A control arrangement according to claim 15, wherein the control lines or the crew lines are attached to a foot bar which is operable to be controlled by the user's feet.18. A control arrangement according to any one of claims 9 to 14, wherein the control lines or the crew lines are connected to a mechanical control arrangement.19. A control arrangement according to claim 2, wherein the fixing point is moveable to adjust a heeling moment applied by the control arrangement.20. A control arrangement according to claim 19, wherein the arrangement further comprises an arrangement for adjusting the position of the fixing point automatically to stabilise the control arrangement if the control arrangement is subjected to a rolling moment.21. A control arrangement according to any one of the preceding claims, is wherein each of the lines is releasably attached to an attachment element and wherein the length of the lines is adjustable by winding in or letting out the lines from the releasable attachment.22. A control arrangement according to claim 21, wherein the releasable attachment is a rotatable drum which is operable to rotate to wind in or let out the lines.23. A control arrangement according to any one of the preceding claims, wherein the arrangement further comprises a wind powered element which is connected to one end of each line.24. A control arrangement according to claim 23, wherein the wind powered element comprises an aerofoil section.25. A control arrangement according to claim 24, wherein the wind powered element is a kite.26. A control arrangement according to claim 24, wherein the wind powered element is a wing.27. A control arrangement according to claim 26, wherein the wing is collapsible.28. A control arrangement according to any one of claims 23 to 27, wherein the wind powered element incorporates a float arrangement which floats on water.C') 29. A control arrangement according to any one of the preceding claims, is wherein the base unit is mounted to a watercraft.30. A control arrangement according to claim 29, wherein the watercraft Cv) comprises a keel, centreboard or a single element comprising both a keel/centreboard and rudder to resist lateral movement of the boat.31. A control arrangement according to claim 30, wherein the longitudinal axis of the first support member is aligned with the longitudinal axis of the keel or centreboard.32. A control arrangement according to claim 31, wherein the length of the second support member is selected so that the direction of the force exerted by the wind powered element on the drive line extends substantially through the centre of lateral resistance of the combined hull, keel or centreboard, rudder and other appendages when there is no overall moment applied to the second support member in the first or second planes.33. A control arrangement according to any one of claims 1 to 28, wherein the base unit is mounted to a land based wind powered vehicle.34. A control arrangement according to any one of claims 1 to 28, wherein the base unit is mounted to a snow or ice based wind powered vehicle.35. A control arrangement according to any one of claims 1 to 28, wherein the base unit is configured to be attached to a boat.36. A control arrangement according to claim 35, wherein the base unit is attached directly to a keel or centreboard which is configured to be attached to a boat.C') 37. A control arrangement according to claim 35, wherein the base unit is is attached directly to a rudder which is configured to be mounted to a boat.38. A control arrangement according to claim 37, wherein the rudder is C) mounted to a boat which does not incorporate a keel or centreboard.39. A control arrangement according to claim 37 or claim 38, wherein the rudder is pivotally mounted to or near the rear of a boat.40. A control arrangement according to any one of claims 35 to 39, wherein the base unit is attached to a boat.41. A control arrangement according to any one of claims 35 to 40, wherein the boat is a kayak.42. A control arrangement according to any one of claims 35 to 40, wherein the boat is a dinghy.43. A control arrangement according to any one of claims 35 to 40, wherein the boat is a yacht.44. A control arrangement according to any one of claims 35 to 40, wherein the boat is a boat selected from a group consisting of a raft, surfboard, ship, canoe, monohull, rnultihull, displacement vessel, planing vessel or a vessel supported on hydrofoils.45. A control arrangement according to claim 44, wherein the control arrangement is mounted to a planing vessel at or near the rear of the planing vessel.46. A control arrangement according to any one of claims 35 to 45, wherein the boat comprises at least one hydrofoil element.o 47. A control arrangement substantially as herein before described with reference to and as shown in any one of the accompanying drawings. C')