This invention relates to a water vehicle.

According to one aspect of the invention there is provided a water vehicle

which includes first and second foils which are at least partly submersible and

which are movable, at least to a limited extent, relatively to each other.

The said relative foil movement may cause, or be due to, at least one of the

following: at least limited rotational movement of the first foil about an axis

which is transverse to a Iongitudinal axis of the first foil; a variation in the

inclination of the first foil about an axis which may extend generally in a

direction which is parallel to the Iongitudinal direction of the first foil.

The water vehicle may include water skimmer means and connection means

which is mounted for pivotal movement about an axis and which connects the

skimmer means to the first foil.

The water vehicle may include a third foil which is at least partly submersible

and which is connected by means of the connecting means to the skimmer

means.

The water vehicle may include a support structure and means securing the foils

to the support structure, the said relative foil movement being due to or caused

by at least one of the following: relative movement between at least two

sections or components of the support structure; relative movement between

the support structure and the securing means; relative movement between at

least one foil and the support structure; relative movement between at least

one foil and the securing means.

The water vehicle may include biasing means which, at least to a limited

extent, dampens the said relative foil movement. The biasing means may take

on any suitable form and may, for example, include a resiliently deflectable or

deformable member, a spring, a shock absorber mechanism, or the like.

The force which is exerted by the biasing means may be adjustable in order to

vary the characteristics of the water vehicle.

According to a different aspect of the invention there is provided a water

vehicle which includes a support structure, at least first and second foils which

are at least partly submersible and which are secured to the support structure,

means which permits limited movement of the first foil relatively to at least part

of the support structure, and steering means for controlling the direction of

movement of the vehicle.

The steering means may comprise rudder means of any suitable type, or

means for causing at least limited rotational or pivotal movement of the first foil

relatively to the second foil.

The aforementioned support structure, which may be in the form of a frame,

may include a platform or the like in order to provide support for a user. The

user may stand on the platform which may include feet engaging formations

such as straps or the like. The frame may be made from any suitable material

such as aluminium, a composite material such as fibre reinforced resin or the

like, or be moulded from suitable material such as a pressure moulded plastics

material.

The foils may be similarly formed and, according to a preferred aspect of the

invention, the foils are formed from extruded or pultruded sections of a suitable

material, e.g. aluminium, or are pressure moulded from a suitable plastics

material.

The invention also provides a method of propelling a water vehicle which

includes the steps of at least partially submerging at least first and second foils

of the vehicle in a body of water, and repeatedly varying the inclination of the

first foil in the body of water.

The surface of the body of water may be contacted by skimmer means which

may be used to control the depth to which the first foil is submerged in the body

of water.

The method may include the additional step of repeatedly varying the

inclination of a third foil, which is at least partly submerged in the body of

water.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention is further described by way of examples with reference to the

accompanying drawings in which:

Figure 1 is a perspective view of a water vehicle according to one

embodiment of the invention,

Figure 2 is a side view of a canard arrangement used in the vehicle of

Figure 1 ;

Figure 3 is a side view of a support structure or frame used in the

vehicle of Figure 1 ;

Figure 4 is a side view of the vehicle shown in Figure 1 ;

Figure 5 is a schematic side view of foils of the water vehicle of Figure

1 ;

Figure 6 is a plan view of the foils shown in Figure 5;

Figure 7 is a view similar to Figure 2 of a canard arrangement according

to a variation of the invention;

Figures 8 and 9 are side views of different support structures according

to variations of the invention; and

Figure 10 is a side view, similar to Figure 4, of a water vehicle which

includes the canard arrangement of Figure 7 and the support structure

shown in Figure 8.

DESCRIPTION OF PREFERRED EMBODIMENTS

Figure 1 of the accompanying drawings illustrates a water vehicle 10 which

includes a support structure or frame 12 and a canard arrangement 14.

The canard 14 is shown from the side in Figure 2. It includes a support 16 to

which is attached a transversely extending Iongitudinal leading foil 18, a lever

20 which is secured at a pivot point 22 to the support 16, an arm 24 which is

attached at a pivot point 26 to the lever 20, a transversely extending V-shaped

foil 28 which is secured to the arm 24, and a skimmer plate 30 at a forward end

of the arm 24. A spring 31, optionally of variable stiffness, can be used to

dampen movement between the support 16 and the lever 20.

The support structure or frame 12 is shown from the side in Figure 3. It

includes a tubular frame assembly 32, a forwardly extending steering rod 34

which is mounted for rotation in a sleeve 36 of the frame assembly 32 and

which is movable by means of a handlebar 38, a platform 40 on the frame

assembly, two downwardly extending support members 42 and 44 respectively,

and a transversely extending Iongitudinal trailing foil 46 which is secured to the

support members 42 and 44.

The support structure and the foils may be made from any suitable material.

Use may for example be made of light weight composite materials such as

carbon fibre, fibre glass or the like, or of light weight metals such as aluminium.

It is also possible to form the various components by means of injection

moulding processes.

The steering rod 34 is attached to the lever 20 of the canard arrangement at

a pivot point 48. Referring to Figure 2 it can be seen that this point is slightly

in front of an upright portion of the support 16.

The platform 40 is adapted to support a user and, for this purpose, locating

straps 50 may be provided on the platform to receive the feet of the user. The

user is able to grip the handlebar 38. By turning the handlebar 38 the steering

rod 34 can be rotated so that, viewed in plan the leading foil 18 and the V-

shaped foil 28, together with the skimmer 30, are rotatable, or pivotable,

relatively to the trailing foil 46. This type of movement is shown, somewhat

schematically, in Figure 6.

The foils 46, 18 and 28 are, in use, submerged in a body of water, not shown.

In Figure 4 the water line is indicated by the numeral 50. The skimmer 30

essentially rides on the surface of the water.

If the user has an initial forward velocity, in the direction of arrow labelled 52

in Figure 4, then due to hydrodynamic effects lift is exerted on the foils with a

magnitude which is sufficient to prevent the water vehicle from sinking into the

water. By bobbing slightly up and down on the platform the user causes the

orientations of the foils in the water to change relatively to one another. In

particular, as is shown schematically in Figure 5, the inclinations of the foils 18

and 28 are varied, relatively to the inclination of the trailing foil 46. Due to

principles which are known in fluid dynamics the forward speed of the vehicle

is maintained or increased. Effectively therefore the bobbing movement of the

user is translated into forward movement of the vehicle and this in turn

provides lift which is exerted on the foils and which ensures that the vehicle

and the user do not sink into the water.

The force on the canard 14 is applied in front of the foil 18. This causes a

slight, yet stable, variation in the inclination of the foils 18 and 28.

The foremost foil 28 is V-shaped to ensure that its wake does not interact with

the downwardly extending support 16.

The user is able to vary the force exerted by the user's legs on the platform

relatively to the force which is exerted by the user through the user's arms on

the handlebar 38. In this way the user can simultaneously generate thrust on

the foil 46 and on the foil 18, with the amount of thrust, in each case,

depending on requirement and ability.

The relative movement between the various foils is made possible, in this

instance, by the pivot connections at the points 22 and 48. This relative

movement can be damped, as has been indicated, by making use of springs,

rubber bushes or any equivalent mechanism, located at a suitable position

between the foils.

Steering of the vehicle is effected, as has been explained, by rotating the

steering rod 34 about its Iongitudinal axis.

Figure 7 shows a canard arrangement 60 according to a variation of the

invention. This arrangement includes a lever 62, a downwardly depending

support 64 to which is attached a longitudinally extending foil 66, and a

skimmer plate 68 at a forward end of the lever. This arrangement is

substantially the same as the leading portion of the canard arrangement shown

in Figure 2.

Figure 10 illustrates the arrangement 60 secured to a steering rod 34 of a

support frame 70, which, in many respects, is similar to the support frame 12

shown in Figure 1. Similar numerals have been employed in Figure 10 to

indicate similar components. Thus the support structure has a platform 40,

downwardly depending support members 42 and 44, and a trailing foil 46.

It is necessary, in order to maintain thrust and achieve lift for the vehicle, that

relative movement should take place between the leading foil 66 and the

trailing foil 46. This may be achieved in various ways. It is pointed out, in

connection with the Figure 1 embodiment, that relative movement is achieved

by means of the pivot connections 48 and 22. An equivalent type of movement

can be achieved in other ways.

Referring to Figure 10 the support structure, which is also shown in Figure 8,

includes two sections designated 70A and 70B respectively. These are

connected to one another at a pivot point 72. The section 70A supports the

platform 40 while the section 70B has the steering arrangement attached to it.

A small degree of pivotal movement of one section can take place relatively to

the other section. A compression spring 74 interconnects the two sections.

The stiffness of the spring can be adjusted by compressing the spring to a

greater or lesser extent using a suitable screw mechanism. Thus, when a user

bobs up and down on the platform 40, relative movement between the foils

takes place with the degree of relative movement depending, at least to some

extent, on the stiffness of the spring.

With the arrangement shown in Figure 10 thrust is generated primarily by the

trailing foil 46 while the leading foil 66 acts as a stabilizer but, on the other

hand, gives rise to drag. The arrangement shown in Figure 10 is therefore less

efficient than the arrangement shown in Figure 1 in which both foils are used

to generate thrust.

As is the case with the Figure 1 embodiment the skimmer plate 68 imparts

further stability to the arrangement and ensures that the foil 66 does not sink

too deep into the water as forward movement of the vehicle takes place.

As an alternative to hinging two sections of the support structure to one

another the structure 70 could be made relatively rigid and the steering rod 34

could be resilient or flexible to some extent. Again, with bobbing movement of

the user on the platform 40, different amounts of force are exerted on the two

foils and relative movement between the foils takes place as the rod 34 flexes.

This permits the inclination ofthe foils to be varied and, in accordance with the

principles which have been outlined hereinbefore, at least the rear foil 46

generates thrust which maintains the forward speed of the vehicle and which

in turn ensures that lift is generated which prevents the vehicle from sinking

into the water.

Figure 9 shows support structure 80 according to a variation of the invention.

Again like reference numerals have been employed to designate like

components. In this case a degree of relative movement between the trailing

foil 46 and the support structure is permitted by mounting the support members

42 and 44 to the support structure at hinge or pivot points 82. These points

could include torsion mounts such as rubber axles or, alternatively, the degree

of relative movement could be constrained by making use of biasing members

similar to what is shown in Figures 8 and 10.

It is apparent that it is possible to permit the angular orientation of one foil to

be varied relatively to the orientation of the other foil or foils, in a variety of

ways. For example the entire support structure may be formed from a suitable

flexible material. One could also make use of elastic bushes or mounts which

secure the foils, or structure which supports the foils, to the support structure

70.

The degree to which the foils can move relatively to one another is important

and this is determined by trial and experiment and by experience of the user.

As the vehicle traverses through the water body in which it is operated the

skimmer plate impinges on the water surface. This helps substantially in

maintaining stability for it assists in keeping the leading foil more or less at the

desired depth in the water. If the leading foil sinks too low then a greater

reactive force is exerted by the water surface on the skimmer which tends to

correct the situation. On the other hand if the leading foil tends to rise from the

water then a restoring force is automatically exerted by gravity action which

effectively rotates a leading end of the vehicle closer towards the water body.

The foils may be made in any appropriate way and, in one example of the

invention, the foils are made from extruded sections for example of aluminium

or a plastics material. The foils may have constant cross-sections or be formed

with tapers. The foils are preferably hollow and are sealed at opposed ends

by means of suitable plugs.

Another variation is to make use of a rudder to steer the vehicle, instead of, or

if required, in addition to, pivoting one foil relatively to the other. For example,

referring to Figure 4, a hand or foot-controlled rudder 80 could be fixed at any

suitable location to the support structure of the vehicle. By controlling the

orientation of the rudder the vehicle can be steered.