WO2002012044A1

WO2002012044A1 - A ground effect craft

Info

Publication number: WO2002012044A1
Application number: PCT/AU2001/000944
Authority: WO
Inventors: Wayne Cramer
Original assignee: Wayne Cramer
Priority date: 2000-08-04
Filing date: 2001-08-03
Publication date: 2002-02-14
Also published as: AUPQ921100A0

Abstract

A craft having symmetrical wing portions on either side of a central longitudinal axis, with the wing portions curving downwardly at their outer ends and having a lower surface profile which curls outwardly and downwardly, whereby an airflow pattern is able to be created underneath the craft which curls outwardly so as to lift the craft off a surface.

Description

A GROUND EFFECT CRAFT FIELD OF THE INVENTION

The present invention relates primarily to craft which are able to move over a ground surface such as land or water by creating an air pressure wave between its lower surface and the surface over which it is travelling. BACKGROUND OF THE INVENTION

A hovercraft is one type of ground effect craft which is able to create air pressure between its lower surface and the opposing ground surface in order to lift it above the ground surface . In the case of a hovercraft a flexible skirt is provided in order to create the necessary flow of air on which the hovercraft can ride. Other ground effect craft include wings like aeroplanes which are specially designed to enable the craft to ride on a pressure wave above a ground surface.

The main problem with existing ground effect craft is stability. Existing ground effect craft include a tail. The tail is necessary because existing ground effect craft effectively ride on the edge of a wave of air which is created between the lower surface of the craft and the surface over which the craft is moving.

Because the nose of the ground effect craft is lifted upwardly a certain distance by the pressure wave below it_# the tail section of the craft is generally beyond the width of the wave and is susceptible to rising and falling uncontrollably. Therefore a tail located at the rear of the craft is able to provide the craft with the ability to control vertical movement of the tail section of the vehicle.

The provision of a tail however adds to the complexity of the craft and accordingly requires some type of linked controlling mechanisms.

The present invention provides an alternative type of ground effect craft which preferably is able to operate over any type of ground surface. SUMMARY OF THE INVENTION According to the present invention there is provided a ground effect craft having a nose section with wing sections on either side thereof, wherein the craft has a lower surface which curves outwardly and upwardly from a central section with a decrease in gradient to a point of zero gradient and downwardly from the point of zero gradient with increasing gradient to a lower edge section, whereby air passing under the craft is forced to roll outwardly as it passes rearwardly to create a pressure wave on which the craft is able to be supported. It is noted that for convenience the above statement of invention has been described having regard to the gradient of curve which the lower surface approximates . According to another aspect of the invention there is provided a ground effect craft having symmetrical wing portions on either side of a central longitudinal axis, with the wing portions having lower surfaces tapering generally downwardly from front to back of the craft and curving generally downwardly from the central longitudinal axis to the wing tip, whereby an air flow pattern is able to be created underneath the craft so as to lift the craft off a surface.

According to a further aspect of the present invention there is provided a craft comprising symmetrical wing portions on either side of a central longitudinal axis, each wing portion curling outwardly and downwardly from the central longitudinal axis to the wing tip, whereby an airflow pattern is able to be created underneath the craft which curls outwardly so as to lift the craft off a surface.

Preferably the craft includes a hull aligned with the central longitudinal axis and located below the level of the wing portions proximate the central longitudinal axis.

It is preferred that the wing portions include front edges which taper rearwardly and outwardly towards wing tip portions.

According to one embodiment the craft includes water deflecting means at a front portion thereof.

According to a further embodiment of the present invention the craft includes a downwardly directed tail fin which is adapted to stabilise the craft against sideward movement .

The water deflecting means preferably comprises downwardly curving fins. The downwardly curving fins preferably flare outwardly and rearwardly.

Preferably each wing portion initially curves upwardly from the central longitudinal axis.

Preferably the wing portions are shaped to direct air flowing underneath the craft to move rearwardly and outwardly to create a laterally moving pressure wave.

It is preferred that the craft is able to generate an air pressure wave thereunder, which rolls outwardly as it travels from front to back of the craf . The craft is preferably able to create flaring wave fronts on either side of the central longitudinal axis.

Preferably the wave fronts are created on either side of a hull portion of the craft . It is preferred that a major part of the lower surface is shaped to create a ground effect air flow pattern underneath the craft .

According to one embodiment of the present invention each wing portion has a lower front section having a generally parabolic shape.

According to another embodiment of the present invention each wing portion has a front profile which is generally concave.

According to a further embodiment of the present invention each wing portion has a mid section which forms a peak.

It is preferred that a front profile of the craft is characterised by each wing portion having a wave like appearance.

The width of the craft is preferably greater at the front than at the back. The wing span of the craft may decrease from front to back.

Preferably the craft comprises a hull which is aligned along the central longitudinal axis.

The hull preferably decreases in height from front to back.

The craft may include a nose section which flares outwardly to the wing portions.

Preferably the nose section is located at a top front section of the craft. The nose section preferably curves initially upwardly then downwardly from its forward most tip.

The tip of the nose section is preferably lower than a mid section of each wing section at a front end thereof . It is preferred that the tip of each wing portion is directed downwardly.

It is preferred that an inner portion of each wing portion curves upwardly.

Each wing portion may curve rearwardly and outwardly, with an initially decreasing gradient.

Preferably each wing section curves downwardly with slightly increasing gradient from a zero gradient portion thereof.

It is preferred that each wing portion curves from the hull section to the tip of each wing portion, initially upwardly with decreasing gradient to a peak and then downwardly at generally increasing gradient to the wing tip.

Preferably the craft has a rounded nose section. Each wing tip preferably is rounded at a front edge thereof .

Preferably each wing portion tapers downwardly from a front edge to a rear edge .

Each wing portion preferably tips downwardly at an outer region thereof .

The nose section preferably dips down towards its tip.

Preferably each wing portion has outer side edges which taper inwardly from front to back.

Each wing portion may comprise three main sections, namely front, middle and rear sections. Each front section preferably tapers outwardly at a steep gradient at generally around 50 to 60° with respect to a horizontal ground surface.

Each middle section preferably has an edge which tapers inwardly at a lower gradient of generally 5 to 20° with respect to a horizontal ground surface.

Each rear section has an edge which tapers inwardly from the middle section edge at a constant gradient to a rear edge, the constant gradient being approximately 40 to 60° with respect to the edge of the middle section.

Each rear edge is preferably perpendicular to the central longitudinal axis.

Each rear edge preferably extends outwardly at 90° with respect to the hull. It is preferred that the outer region of each wing section dips downwardly.

Preferably the craft includes left and right scalloped regions extending on either side of the central longitudinal axis from the front section of each wing portion to enhance ground effect on a front portion of the craft.

Preferably the scalloped region extends from a front edge rearwardly to an unscalloped region.

The unscalloped region may have a front edge profile comprising a narrow head section which extends rearwardly to a wing region where the front edge curves laterally to the tip of the wing region which is close to the innermost edge of the middle section.

The head section preferably extends from approximately a front of the middle section to the second third of the middle section where the front edge curves outwardly forming a concave shaped front edge.

The head section is preferably rounded and finger-like in shape.

The unscalloped region may have an outer narrowed front tip section. The overall shape of the craft is preferably sting ray shaped.

The scalloped region preferably forces air outwardly and rearwardly with an initial upwardly extending curve which is more pronounced than embodiments without the scalloped region.

The lower surface of the craft preferably tapers initially in an upward curve from a front edge through the scalloped region and then through a downward curve to the front edge of the unscalloped region. The unscalloped region preferably tapers gradually rearwardly and outwardly.

The front edge of the unscalloped region preferably forms a ridge for forcing air downwardly.

It is preferred that the craft has peripheral edges which are adapted to direct air flowing under the craft to move downwardly.

It is preferred that the craft includes a supporting region on its upper surface, which supporting region is adapted to receive a person or load. It is preferred that the craft includes holding portions whereby a person is able to hold onto the craft.

Preferably lateral movement of the craft is able to be controlled by redistributing a mass located on the craft. It is preferred that a person located in the supporting region is able to move to change the lateral direction of movement of the craft . According to another embodiment of the present invention the craft includes a driving means for generating air flow underneath the craft.

It is preferred that the hull of the craft includes a narrowed front nose section and a generally thickened body region.

It is preferred that the wing portions are tilted downwardly from front to back.

It is preferred that a front section of the hull flares outwardly as it extends rearwardly into the wing portions.

It is preferred that the supporting portion comprises a depression in a central region of the upper surf ce of the craf . It is preferred that the front section of the craft comprises a curved front lower surface.

It is preferred that the front lower section is generally convex.

It is preferred that the holding portions comprise laterally extending bars.

Preferably the location of the laterally extending bars can be changed to various locations along an upper forward section of the upper surface.

According to the preferred embodiment of the present invention which will be described hereinafter, the specific shape of the craft as shown in the drawings has particular advantages to operation of the craft as a ground effect craft .

According to another embodiment of the present invention the craft includes an attachment portion whereby a tether may be connected to the craft in order to pull the craft behind a motorised craft.

It is preferred that the craft is able to be pulled behind another vehicle as a recreational craf . According to another embodiment of the invention the craft is able to be driven by an onboard driving means . The onboard driving means may be propellers, fans, or other air flow generating apparatuses or other medium flow generating apparatuses.

According to one embodiment of the invention the tail section can be as high as the nose section.

It is preferred that the profile of the underside of the craft is designed so that at the tips of the wings of the craft air is forced down at between 85° and 95° with respect to a horizontal plane above the wings. It is preferred that for low speeds the craft has a skirt which assists in capturing flow of air under the craft.

The degree of scalloping of the underside of the wings can be increased or decreased to increase the steepness of the roll of the air wave created below.

The invention covers a ground effect craft which operates in a variety of different media. For example the ground could be air, water or any other media, so that for example, the invention could be a water vehicle travelling over a ground surface, an air vehicle travelling over a different air surface, an air to ground or air to water surface, or other combinations of media.

Because the craft may also operate in other media where embodiments have previously referred to air flow, it should be noted the invention covers any flowing media on which the ground effect craft is able to operate.

It should be noted that words such as "having" and "comprising" are intended to be used in an inclusive rather than an exclusive sense. According to another embodiment of the present invention front and back edges of the wing portions of the craft may have downwardly extending tips in order to enhance capture of air flow therebelow.

The words "comprising, having, including" should be interpreted in an inclusive sense, meaning that additional features may also be added. BRIEF DESCRIPTION OF THE DRAWINGS Preferred embodiments of the present invention will now be described by way of example only with reference to the accompanying drawings in which:

Figure 1 shows an isometric view of a ground effect craft according to one embodiment of the present invention;

Figure 2 shows a front elevation of the craft shown in Figure 1;

Figure 3 shows a rear elevation of the craft shown in Figure 1;

Figure 4 shows a front view of the craft with a schematic representation of air flow;

Figure 5 shows a side view of the craft shown in Figure 1; Figure 6 shows a top view of one half of the craft shown in Figure 1;

Figure 7 shows a side view of the craft shown in Figure 1 incorporating air flow patterns;

Figure 8 shows a top front view of the craft shown in Figure 1;

Figure 9 shows a lower front view of the craft shown in Figure 1;

Figure 10 shows a bottom view of the craft shown in Figure 1; Figure 11 shows a top perspective view of a ground effect craft according to a second embodiment of the present invention;

Figure 12 shows a bottom front perspective view of the second embodiment of the invention; Figure 13 shows a front view of the second embodiment of the invention;

Figure 14 shows a front angled view of the second embodiment of the invention;

Figure 15 shows a side view of the second embodiment of the invention;

Figure 16 shows a rear end view of the second embodiment of the present invention; Figure 17 shows a bottom view of the second embodiment of the present invention;

Figure 18 shows a top view of the second embodiment of the present invention; and Figure 19 shows a top view of a top handle bars of the second embodiment of the present invention. BEST MODE FOR CARRYING OUT THE INVENTION

As shown in Figures 1 and 5 the ground effect craft according to the preferred embodiment consists of a centrally located hull 11 which extends from the front of the craft 12 to the rear end of the craft 13.

The hull 11 has the general appearance of the hull of some types of water craft with specific differences which are peculiar to the preferred embodiment of the invention.

The hull 11 when positioned on a flat surface as shown in Figures 1 to 9 has a narrow flat generally V- shaped bottom surface 14.

The front section 12 of the hull curves upwardly from the base 14 with gradually increasing gradient to a nose tip 16 located at the forward most part of the craft 10.

From the tip 16 the hull extends into a nose section 17 which has a slightly upwardly curving upper surface 17 which reaches a peak 18 and continues curving downwardly at a generally constant angle/slope towards the rearmost tip 13 of the craft 10.

From the above description of the hull which is described primarily with reference to Figure 5 it will be apparent that the height of the hull 11 is highest at the point 18 and gradually decreases in height to the rear end 13 of the craft 10.

Figure 5 shows specific dimensions of a prototype craft according to the preferred embodiment . When viewed from above as shown in Figure 6 the craft 10 is symmetrical about a central longitudinal axis 20 which extends through the hull 11. On either side of the central longitudinal axis 20 the craft is best described as having wings 21 and 22. Figure 6 shows only right side wing 21. For convenience the right wing 21 will be considered as three separate regions. The first region being the front region 22, the second region being the middle region 23 and the third region being the back region 24.

The front region 22 has a contoured front edge 25 which begins at the tip of the nose 16 and curves outwardly and rearwardly at a slight angle to a first point 26 where the curve of the front edge 25 begins to gradually increase in gradient with respect to the central longitudinal axis. The front edge 25 continues to curve outwardly to the front outer edge 27 of the wing 21. This outer edge 27 is rounded and extends into the outer edge of the middle section 23.

The outer edge 28 of the middle region 23 is essentially parallel to the central longitudinal axis and extends to the beginning of the edge 29 of the rear region 24.

The rear edge 29 tapers inwardly at a generally constant angle of approximately 45° with respect to the longitudinal axis.

At the rearmost end 30 of the rear region 24, the rear edge 31 extends inwardly at right angles to the central longitudinal axis where it meets the rear edge of the other wing 20. The point at which the rear edge 29 extends into the rearmost edge 31 occurs at a point which is approximately one third of the width of the wing away from the central longitudinal axis.

The point 26 where the gradient of the front edge changes from decreasing to increasing is approximately one quarter of the width of the wing from the central longitudinal axis 20. Figure 2 shows a front profile of the craft 10.

From this figure the design of the shape of the under surface of the craft 20 can be viewed.

The front edge 25 of each wing can be seen to initially slope upwardly through edge 26 to a peak 32 which is located approximately three quarters of the width of each wing from the central longitudinal axis 20.

From the peak 32 the wings curve downwardly and rearwardly to the front outer edge 27. The hull 11 flares outwardly from the central longitudinal axis and its lowermost point 14 in an initially upwardly extending curve 33 which reaches a peak 34 and curves downwardly and outwardly to the outermost underside of each wing 21, 22. On top of the craft 10 a hollowed out central person support region 36 is provided which is designed to provide an area on which a person is able to lie face down and hold onto removable handle bars 37 which are located between the nose region 17 and the forward-most edge 38 of the person support region 36.

The handle bars 37 look similar to handle bars of a bicycle and are received within handle bar shaped recesses located between noise region 17 and edge 38.

Each handle bar recess 39 allows the handle bars 37 to be located in a position which is most comfortable for a person lying on the craft and also provides a means for varying the point at which a towing line may be attached to the craft 10.

Thus the handle bars 37 are provided with a towing line 40 which connects to lugs located on either side of the centre of the handle bars 37. The handle bar recesses 39 are designed so that when a person holds onto the handle bars when located in one of the recesses 39, the craft is able to be towed behind another vehicle. As soon as the handle bars 37 are released they rotate forwardly within the recess 39 within which they are located and immediately are able to release from the recess 39 and thus enable the towing line to be detached from the craft 10.

As shown in Figures 4 and 7 the craft 10 to be towed captures air pressure by forward motion generating lift with lines 1 to 6 showing general air flow generating a pressure wave underneath the craft and a bow wave in front of the craft which the craft will ride upon and in effect reduce drag on both surfaces so as to produce a rotating vortice and pressure wave. The wing shapes force and direct air at edges to form an air curtain retaining air pressure under the wings following the outer edge of the wing.

In operation according to the preferred embodiment a person located in the zone 36 holds onto the handle bars 37 while the craft 10 is towed behind a motorised vehicle such as a speed boat. Because of the design of the craft 10, air flowing underneath the craft

10 is forced to move outwardly as it moves rearwardly as shown by the flow patterns 40 in Figure 4. Air flow is thus forced outwardly and downwardly in a rolling curve to create a cushion of air on which the craft 10 is able to "ride".

The gradual tapering of the wings from front to back as shown in Figure 7 results in a pressure wave created underneath the craft 10 having decreasing height from front to back.

As a consequence the craft 10 lifts off of a ground surface whether this be land or water and the craft 10 tilts slightly upwardly because of the greater air pressure created underneath the front portion of the wings as opposed to the rear portion of the wings.

The outer edges of the wings are downwardly curved to ensure that air flow is directed downwardly to create a wave on which the craft 10 is able to be supported.

The craft may be modified with a peripheral skirt to enhance the ability of the craft 10 to create an outwardly directed wave on which it is able to be supported.

With the pressure waves moving rearwardly and outwardly, the craft is able to move forward with a greater degree of stability than would be the case with a ground effect vehicle riding on a pressure wave which is only able to travel from front to back of the craft .

In effect the craft 10 is able to sit between two outwardly moving pressure waves which decrease in height from front to back.

As a consequence the tail section of the craft 10 is also supported by the pressure wave(s) below the craft 10 and does not bounce up and down as would be the case in a conventional ground effect vehicle on a pressure wave moving from front to back of the vehicle.

Direction of movement of the craft 10 can be changed by redistributing weight from one wing to another. Alternatively the nose of the craft 10 can be oriented to one side or the other of the longitudinal axis in order to make the craft move laterally in that direction.

According to one example a person lying in the region 36 is able to move their head to one side of the longitudinal axis and make the craft 10 move laterally to the other side of the longitudinal axis. The design of the lower surface of the craft 10 can be modified in order to create different pressure wave patterns to enhance particular characteristics of the craft 10 when in operation.

Thus as shown in Figure 10 and Figure 6 the underside of the craft 10 may have a scalloped out region

50 located in a forward region of each of the wings 21, 22.

The scalloped region effectively results in a more rapid tapering of the rearward curvature of the lower surface of each wing 21, 22.

This scalloped region 50 thus increases the height of the pressure wave flying underneath the craft 10 at the front of the craft 10. This results in greater uplift of the front of the craft 10.

The degree of lift of the front of the craft with respect to the rear of the craft may be varied by changing the amount of scalloping underneath the craft and the rate at which the scalloping occurs from front to back of the craft 10.

Thus without the scalloping the underside of the craft has a gradually rearwardly tapering curvature which extends all the way to the rearmost edges 29, 30.

The shape of the scalloping as shown in Figure 6 for one wing results in a rearward unscalloped region 51 having an initial head section 52 which curves outwardly and rearwardly at an angle of approximately 45° and then curves forwardly to a forward outer edge of the wing 21.

The curve which separates the scalloped region 50 from the unscalloped region 51 results in a ridge being formed between these two regions. For the unscalloped region 51 a more gradual tapering of curvature from front to back occurs from this ridge 55.

It is noted that for the preferred embodiment the base of the hull 14 is effectively a lower spine although variations to this design are encompassed including a more flattened lower surface 14 and additional parallel spines or fins.

A second embodiment of the present invention will now be described in detail with reference to Figures 11 to 19.

A ground effect craft 60 is shown in Figure 11 which is specifically adapted for use over water.

The craft 60 has a similar overall shape to the craft shown in Figures 1 to 10. In contrast however the craft 60 includes a water deflection formation 61 as part of its hull 62. The water deflection formation 61 consists of left and right side fins 63, 64 located close to the front of the u-shaped hull 65.

Each fin 63, 64 flares downwardly and outwardly and terminates at a rearward point 66 of the hull which corresponds approximately to the maximum height of the craft as well as being just below the positioning of handle bars 67 on top of the craft 60. The front edges 68, 69 of the fin 63, 64 flare outwardly as they extend rearwardly. These front edges 68, 69 have generally planar curved faces which act as a deflector surface for any water that strikes them.

From the outer most edges 70, 71 of the front edges 68, 69 the fins extend rearwardly and appear as skirting 72, 73. For the first half of the length of skirting 72, 73, it extends generally parallel if not slightly outwardly from the main hull 62. Thereafter it converges back towards the hull 62 which it meets at point 66.

The hull 62 has a similar configuration to the craft of the first embodiment. At the rear end however it has a centrally located tail fin 74 having a general wing foil configuration from front to back. The main purpose of the water deflection formation 63, 64 is to enable the craft 60 to start on the surface of water and to lift off of the surface so that the aerodynamics of the craft construction can come into play and allow the craft 60 to move above the level of the water surface as a ground effect craft.

The water deflection formation 63, 64 deflects water striking the front of the craft 60 from interfering with air flow passing under the craft 60. Without the water deflection formation 63, 64, water tends to act as a drag on the craft 60 and prevents a stable flow pattern of air underneath the craft 60.

Water flowing under the craft 60 also tends to buffet the craft 60 causing it to move or slew from side to side. The tail fin 74 is able to maintain the craft 60 with its front end facing normal to the direction in which it is moving forward. Once an air pressure wave has been created under the craft 60 it is able to lift off of the surface of the water and the pressure wave created thereunder is able to allow the craft 60 to move over the surface of the water at a predetermined height as determined by the design parameters associated with ground effect craft.

As shown in Figure 19, handle bars 67 on top of the craft are made with a nose formation 77 which is connected to the nose section of the craft in alignment with the central longitudinal axis. The handle bars 67 consist of left and right side handles 75, 76.

According to another embodiment of the present invention the craft 60 may be changed to eliminate the water deflection formation 63, 64 and the tail fin 74 by providing skis on an undersurface of the craft 60.

The skis in this embodiment allow the craft to initially lift above the level of water so that water does not interfere with the air pressure wave created under the craft. According to a further embodiment the craft may include a floating platform on which the craft is able to rest, whereby the platform ensures water does not interfere with air flow underneath the craft during launching. According to another variation of the present invention the craft according to the first embodiment of the invention may include supporting wheels to allow the craft to be pulled along a land surface to enable the craft to reach a speed whereby it is able to lift off the ground surface and operate as a ground effect craft.

It is to be understood that, if any prior art publication is referred to herein, such reference does not constitute an admission that the publication forms a part of the common general knowledge in the art, in Australia or in any other country.

Claims

1. A craft having symmetrical wing portions on either side of a central longitudinal axis, with the wing portions curving downwardly at their outer ends and having a lower surface profile which curls outwardly and downwardly, whereby an airflow pattern is able to be created underneath the craft which curls outwardly so as to lift the craft off a surface.

2. The craft as claimed in claim 1 including a nose section which curves downwardly towards a front edge.

3. The device as claimed in claim 1 or 2 wherein the craft has a lower surface which curves outwardly and upwardly from a central section with a decreasing gradient to a point of zero gradient and downwardly from the point of zero gradient with increasing gradient to the wing tip.

4. The craft as claimed in any one of the preceding claims wherein air passing under the craft is forced to roll outwardly as it passes rearwardly to create a pressure wave on which the craft is able to be supported.

5. The device as claimed in any one of the preceding claims wherein the lower surfaces of the wing portions taper generally downwardly from front to back of the craft.

6. The craft as claimed in claim 5 wherein each wing portion initially curves upwardly from the central longitudinal axis.

7. The device as claimed in claim 6 wherein the wing portions are shaped to direct air flowing underneath the craft to move rearwardly and outwardly to create a laterally moving pressure wave.

8. The craft as claimed in claim 7 wherein each wing portion has a lower front section having a generally parabolic shape.

9. The craft as claimed in claim 8 wherein each wing portion has a front profile which is generally concave .

10. The craft as claimed in claim 9 wherein each wing portion has a mid-section which forms a peak.

11. The craft as claimed in claim 10 wherein the wing span of the craft decreases from front to back.

12. The craft as claimed in claim 11 including a nose section which flares outwardly to the wing portions.

13. The craft as claimed in claim 12 wherein the nose section is located at a top front section of the craft.

14. The craft as claimed in claim 13 in which the nose section curves initially upwardly then downwardly from its forward-most tip.

15. The craft as claimed in claim 14 wherein the tip of the nose section is lower than a mid section of each wing section at a front end thereof .

16. The craft as claimed in claim 15 wherein an inner portion of each wing portion curves upwardly.

17. The craft as claimed in claim 16 including a rounded nose section.

18. The craft as claimed in claim 17 in which each wing portion has outer side edges which taper inwardly from front to back.

19. The craft as claimed in claim 18 wherein each wing portion comprises three main sections, namely front, middle and rear sections, with each front section tapering outwardly at a steep gradient from the central longitudinal axis.

20. The craft as claimed in claim 19 wherein each middle section has an edge which tapers inwardly at a lower gradient of generally 5 to 20° with respect to a horizontal surface.

21. The craft as claimed in claim 20 wherein each rear section has an edge which tapers inwardly from the middle section edge at a constant gradient to a rear edge, the constant gradient being approximately 40 to 50° with respect to the edge of the middle section.

22. The craft as claimed in any one of the preceding claims including left and right scalloped regions extending on either side of the central longitudinal axis from the front section of each wing portion on the lower surface of the craft.

23. The craft as claimed in claim 22 wherein the scalloped region extends from a front edge rearwardly to an unscalloped region in a mid region of the craft.

24. The craft as claimed in claim 1 including a lower surface having a scalloped front region which extends to a mid section of the craft at which point the lower surface curves downwardly and outwardly.

25. The craft as claimed in any one of the preceding claims including a supporting region on its surface, which supporting region is adapted to support a load.

26. The craft as claimed in claim 25 including at least one support bar which is able to be held by a person supported on top of the craft.

27. The craft as claimed in any one of the preceding claims including a hull extending along at least part of the central longitudinal axis and having a generally narrow base which extends upwardly and outwardly to the lower surface of each wing portion.

28. The craft as claimed in claim 27 wherein the hull has a generally V-shaped configuration.

29. The craft as claimed in claim 28 including a water deflection means located at a front region of the hull.

30. The craft as claimed in claim 29 including a tail fin extending downwardly from a lower surface of the craft .

31. A craft substantially as hereinbefore described with reference to one of the embodiments as shown in the accompanying drawings .