AU2003204628A1 - Water Craft - Google Patents

Description

Regulation 3.

AUSTRALIA

PATENTS ACT 1990 COMPLETE SPECIFICATION FOR A STANDARD PATENT

(ORIGINAL)

Name of Applicant: Actual Inventors: Address for Service: Invention Title: Glen Cyril Elliot Solly Glen Cyril Elliot Solly DAVIES COLLISON CAVE, Patent Attorneys, Level 3, 303 Coronation Drive, Milton 4064, Queensland.

"Water Craft" The following statement is a full description of this invention, including the best method of performing it known to me: Q:\OPERPMTVhJNEUUNE 2003\12176922.161.DOC 10/6/03 -1- WATER CRAFT FIELD OF THE INVENTION This invention relates to water craft particularly personal water craft such as body boards, surf boards, canoes and similar. More specifically the invention is directed to a guidance or stabilising system for water craft and which may be used as a replacement or addition to traditional features such as fins and keels.

BACKGROUND OF THE INVENTION Personal water craft have long been used for recreational purposes. These water craft include body boards, surf boards, surf skis and kayaks and other personally powered devices. This group also extends to powered watercraft. Typically, directional control systems in these water craft range from nothing at all through to the use of one or more fins protruding from a bottom surface and below the bottom line. The purpose of the fins is to provide lateral stability to the water craft as well as a longitudinal line of least resistance in motion thereby providing an element of directional stability and control.

One identifying feature of these water craft is that they usually have a substantially flat or planar bottom surface although this surface may be curved fore and aft and/or side to side.

Although fins provide some advantages they also have an element of detriment in that they increase drag and also provide a relatively focused point of resistance to lateral movement thereby tending to provide a pivoting motion around a fin or fins which may need to be counteracted by a user if not desired in any particular manoeuvre. Further the fin or fins on a body board may exit from the water, particularly in circumstances when a surfer is cutting across the face or wave. At this stage, the effect of the fins may be minimised and reliance may be placed on -2the ability of the edge of the body board or water craft to hold or cut into the wave face. This edge is sometimes referred to as a rail. In the event that the rail does not cut into and hold onto the face of the wave, a board and rider will tend to slide or slip down the face of the wave losing momentum and being susceptible to engulfment by the wave.

Skilled board riders rely on movement of their board relative to the wave to perform tricks and manoeuvres which extract maximum reward from a wave.

These tricks and manoeuvres often form the basis of judging in amateur and professional competitions. The vigorousness and speed of these tricks and manoeuvres are to a degree limited by the ability of the guidance system of the board to respond to a users directions as well as providing stability during manoeuvres. In any manoeuvre which requires rotation of the water craft, it is preferred that the fins are cleared from the water or alternatively their resistance to lateral motion be overcome by the activities of the user. it would be advantageous to provide an alternative guidance or stabilising system for water craft especially those with a substantially flat bottom.

SUMMARY OF THE INVENTION Throughout this specification, unless the context requires otherwise, the word "comprise", or variations such as "comprises" or "comprising", will be understood to imply the inclusion of a stated element or integer or group of elements or integers but not the exclusion of any other element or integer or group of elements or integers.

In one form, although it need not be the only or indeed the broadest form, the invention resides in a water craft comprising: a top deck; a side wall continuous with the top deck; a bottom surface continuous with the side wall, the bottom surface including at least one channel, said channel comprising a forward intake section, a rearward discharge section and a throat section intermediate and narrower than the intake section and discharge section. The channel is preferably configured to provide a venturi effect during water flow therethrough. The channel may have a side wall that is a continuous curve in cross section. Alternatively, that at least one channel may have a side wall or side walls angled to an adjoining wall.

The channel is positioned in an area of the watercraft which is under water, at least most of the time, during use. The side wall may form part of a hull of a vessel.

Preferably the water craft has two channels. The two channels may each be located adjacent a respective lateral side wall. The watercraft may have three or more channels.

Preferably the intake section opens both forwardly and laterally. Preferably the discharge section opens at least partially laterally.

The at least one channel may include one or more fins mounted therein. The one or more fins may be mounted centrally in the channel. The one or more fins may be entirely enclosed within the space of the channel. Alternatively the one or more fins may protrude beyond the space of the at least one channel. Most preferably the one or more fins are located centrally in the throat section of the at least one channel.

Preferably the top deck includes a back support means. The back support means may be a lumbar support means. The lumbar support means may comprise a lumbar flexion-inducing ridge. The lumbar flexion-inducing ridge may cooperate with a chest recess to support the back of a user. The top deck may further comprise a chin support structure.

Preferably the outer perimeter of the water craft defines an anterior section and a tail section. The tail section may be narrower than the anterior section. The tail -4section preferably also comprises a rearward scalloped side wall. The scalloped side wall preferably has a forwardly sloping angle. The anterior section may have a convexly curved outer perimeter. The tail section may have lateral side watlls which are substantially parallel.

The watercraft is preferably a body board or a surf board. The watercraft may be a surf ski, a kayak or a canoe.

BRIEF DESCRIPTION OF THE DRAWINGS Figure 1 is a top view of a body board of the present invention.

Figure 2 is a bottom view of the body board of Figure 1.

Figure 3 is a perspective view of the body board of Figure 1.

Figure 4 is a front view of the body board of Figure 1.

Figure 5 is a rear view of the body board of Figure 1.

Figure 6 is a side view of the body board of Figure 1.

Figure 7 is a bottom view of a second embodiment of a body board of the present invention.

Figure 8 is a perspective view of the rear of water craft with three channels.

Figure 9 is a perspective view of a surf board with three channels.

DETAILED DESCRIPTION OF THE DRAWINGS The reference to any prior art in this specification is not, and should not be taken as, an acknowledgment or any form of suggestion that that prior art forms part of the common general knowledge in Australia or any other country.

Referring to Figure 1 there is seen a top view of a body board 10 having a top deck 11. The body board 10 has an anterior section 12 and a tail section 13. The anterior section 12 has slightly curved lateral edges or walls 14, 15 which curve away from each other initially in a forward to aft direction before curving back towards each other in a transition zone 16, 17 before forming the side edges or walls 18, 19 of the tail section 13 which is narrower than the anterior section. The curves are shown in the anterior section as convex.

The top view or plan shape of the body board 10 may approximate the shape formed by sectioning a curved venturi channel longitudinally, sliding one section laterally over the other section to provide spaced outer edges and subsequently transversely sectioning the anterior extensions and shortening the tail section, with some curved modification. Although a narrower tail section is shown, it is clear to a skilled addressee that other shapes may be suitable. For example, conventional substantially straight sides may be preferred in certain circumstances.

The tail section has a scalloped rear edge 20 which in the present case has a sloping edge or wall 21 which forms a forwardly sloping stern. The advantage of the sloping edge provides easy and comfortable access for a user as well as assisting in embracing and reinforcing stability of the user through the retentive effect of the scallop.

The top deck 11 includes a back support means in the form of ridge 22 which is situated behind a chest depression 23 so that a rider may comfortably place his or her chest into the depression 23 while at the same time being supported by the ridge 22 which encourages lumbar flexion or resists lumbar hyper-extension. This positioning leads to a minimisation of the tendency to backache from over extension during prolonged use of a body board. A rider may also advantageously be positioned by use of the chin support or squab 24. Fairings 25, 26 are provided for use by a rider to assist in centralising the chest and also for use as a support surface in certain positions.

Venturi channels 27, 28 are located in a bottom surface of the board 10 and are shown in hidden detail. They are described in more detail with reference to subsequent figures.

Figure 2 is a bottom view of board 10 of Figure 1 showing an anterior edge 29 which adjoins an initial slope 30 leading onto a planar section 31 which runs onto intake ramps 32 for each of the venturi channels or keels 27, 28. The intake ramps 32 form part of and lead further into the intake sections 33 which in turn lead into a throat 30 and subsequently into a discharge section The venturi channels 27, 28 are open channels and may be formed by a continuously curved wall when viewed in cross section or alternatively by adjoining walls set at angles such as a top wall and right angled side walls. The physics of a venturi flow are described in part by Bernoulli's theorem, which states that in a stream line flow of an ideal fluid the sum of energy of position (potential energy) plus the energy of motion (kinetic energy) plus the pressure energy will remain constant. As a stream line flow approaches and travels through a venturi duct or channel it goes through changes in pressure and velocity caused by the change in shape of the venturi duct. These changes occur as the streamlined flow is channelled from a convergent duct into a narrowed throat before exiting a divergent duct.

The flow changes in velocity and pressure areas follows: at the entrance to the throat the flow is increasing in velocity and decreasing in pressure; within the throat the flow velocity is highest and the pressure is lowest; at the exit from the throat the flow is decreasing in velocity and the pressure is increasing.

-7- In general the venturi principle applies to a flow channel with a narrow intermediate section when statue, pressure around the inlet, throat and outlet are equal. As fluid flow commences, the velocity of flow in the throat increases relative to the inlet and outlet. Increased velocity causes decreased pressure in the throat. Without seeking to rely on any theory, the inventor notes that this decreased pressure, might result in increased adherence of the craft or "stickability" to surrounding water. While the channel walls are shown as smooth fore and aft curves in the preferred embodiments, other configurations of the walls may be suitable and are within the scope of the invention.

Without wishing to restrict the applicant to any single or set theory, it appears that the present vent channel or vent keel acts in a similar way to a true keel on a water vessel but relies on the use of water more than any physical permanent structure. By channelling water through the venturi channel, the interaction between the channelled water and the surrounding water combined with the pressure differential generates a stability which requires a shear force to break it away. The description of a channel as a "venturi channel" may encompass any structure with a mouth and exit region and a narrower intermediate throat.

At speed a rider may traverse a wave face and turn, a body board for example, on the wave face. This turn is a result of the rail of the body board being held into the wave face. During and after the turn, water is thrown from the base of the board as the rail or edge digs in and turns the body of the board in a radius consistent with the arc. This water or resultant spray is part of the sum of the energy equation, which is required to turn the board on the radius. Other factors in the equation are the opposing force of the wave face against the bottom of the board as well as friction and noise. The total of the sum of these parts combine to result in the radius of turn. Factors effecting the result and rate of turn of velocity of the board and entry to the turn include the type of board and weight of the rider. The venturi channel may harness pressure differentials associated with the venturi to produce a tighter radius of turn although the inventor does not seek to bind himself to any one description or function of the device. The top view or planar shape of the present board assists entry and exit to the venturi channel.

Figure 3 is a perspective view of the body board of Figures 1 and 2. This view highlights the back support ridge 22 cooperating with chest depression 23 and chin squab 24 to position a rider in a comfortable and ergonomically effective attitude. Fairings 25, 26 are also visible, the latter above hand grip 36. The hand grip 36 is matched by a paired hand grip (not shown) on the other side and in a similar position and they are provided to enable a rider to carry the board more easily. A dive plane 37 is also visible rising from the anterior edge 29 to chin squab 24. The dive plane 37 assists a rider in pushing the board under a wave by neutralising the lift produced from an upturned nose. This view also shows the lateral intake 38 portion of the intake section 33 of the venturi keel 28 (shown in outline). The lateral intake 38 cooperates with the intake ramp 32 to scoop water flow into the venturi channel 28. The lateral intake 38 is not essential but does provide an advantage when the board 10 is cutting steeply across a wave face to the extent that the intake ramp 32 may be partially or completely starved of water supply. The lateral intake 38 may provide an auxiliary supply of water which may be urged into the venturi keel 28 by the momentum of the board relative to the wave face and maintain the lateral stability of the board 10 in relation to the wave, thereby providing directional control and replacing or augmenting the traditional effect of the rails of the board. The lateral intake also appears to be effective in minimising or preventing cavitation. In one embodiment, an air release tunnel may be a tunnel created from the channel to a top side of the watercraft.

This view also highlights a lateral discharge feature of the discharge sections It is possible to have the discharge sections directed rearwardly of the board However, the present arrangement results in the venturi keel 28 discharging water clear of the body board thus reducing any net drag effect. This reduction in drag is assisted by the fact that the inner venturi channel may be changed from a divergent angle back towards a slightly convergent angle to allow the "straightened" exit of water at the same angle as that of the local water around the rearward portion of the board. This re-positioning to a convergent angle is shown in the present figures where the inner channel wall does not diverge to the same extent as its anterior section.

It is anticipated that the venturi channel arrangement will work best at high speeds in that, for a given radius of turn, there may be an acceleration of the board and a resulting increase in "hold" of the venturi channel. The tighter the turn the greater the acceleration and so to an extent the venturi channel may reinforce its own effectiveness. The venturi channel may harness a pressure differential associated with the venturi effect and thereby effect the tighter radius of the turn. The "reverse" venturi planar shape may be then used to position the venturi channels to attain the optimum advantage of this pressure differential. The planar shape may assist with entry to and exit from the venturi channel of water flow.

Figure 4 shows a front view of the body board 10 having an anterior edge 29, fairings 25, 26 and chin squab 24. Lateral intake apertures 38 are visible as is planar section 39.

The present invention is particularly well suited to substantially flat bottomed water craft. The expression flat bottom should be understood to include water craft with bottom surfaces that are curved slightly or to a degree both in a fore and aft direction and/or a side to side direction. It is envisaged that the present invention is very well suited for body boards, surf boards, water skis, canoes, kayaks, sail boards and similar water craft.

The present invention may provide a keel-like effect in resisting lateral instability.

It may therefore be beneficially applied in water craft that do not have a projecting keel for improving stability in the water.

The two small protrusions in the form of fairings 25, 26 offer protection to the chest area and also assist in centring the rider. The chin squab allows the rider to place his or her chin in an identified and appropriate position and offers support to the head.

Figure 5 shows a rearward view of the body board in which the chin squab 24 is visible as are the fairings 25, 26 and the sloping end wall 21. The discharge outlets 35 are also visible and clearly inboard of an outermost point of the lateral wall 40. The tail section 13 is clearly narrower than at least part of the anterior section 12 and the view to a rider mounting from behind the board 10 is shown.

The profile of the body board 10 is low despite the additional rider support construction.

Figure 5 also shows areas 41, 42 of very slight slope which facilitate "drop knee" positioning. This involves one knee of a rider being placed in the cockpit or chest depression and the opposite foot being forward and to the side. The areas 41, 42 are ideal positions for the foot, with or without an attached fin.

Figure 6 is a side view of a body board 10 showing the upturned nose 43, dive plane 37 and planar section 39 leading onto the lateral intake 38 and venturi channel 28 having lateral discharge 35. The back support ridge 22, chest depression 23 and chin support squab 24 are also readily apparent.

Figure 7 shows a body board 10 including direction fins 142, 143 located in the throats 134 of venturi keels 127, 128. In one embodiment, the fins 142, 143 may be completely enclosed within the space defined by the walls of the venturi keels 127, 128 and a notional wall across the open section of the venturi channel.

Alternatively, the fins 142, 143 may protrude beyond the bottommost limit of the wall or walls of the venturi channels 127, 128.

When applied to the base of the body board, the channel and fin keels act in a similar way to a true keel or fin. However, instead of the true keel or true fin protruding into the water, the action of the flow of water through the venturi channel creates an interaction between channel water, the fin located in the venturi channel and the surround water immediately local to the base of the venturi board which requires a shear force in order to overcome the lateral stability of the -11 board.

In this embodiment, one of the important purposes of the channels keels is to channel a high speed flow of water to the fin contained therein which is shown located in the throat of the venturi channel. Although the fin is shown as centrally located in the throat, it is clearly possible to vary the position of the fin within the venturi channels 127, 128 although the efficiency of the directional control may be affected thereby. Directing the flow of accelerated water around or over the fins provides the board with a high degree of lateral stability. The location of a fin inside a venturi channel may provide the advantage of decreasing the profile of the combination within the horizontal plane of the base of the body board and keeping the fin from protruding below the base of the board thereby providing a guidance system that may replace or augment existing rails and fins. The advantage may extend also to providing strong lateral stability without the need for a fin to protrude into mainstream flow around the planar base of the board and the base may be kept clean for aerial manoeuvres such as 3600 turns and air roll spins.

The present invention provides a device with the advantage of a narrow or nonexistent profile of protrusions into the water mass. This provides a manoeuvrable water craft which retains lateral stability. In use on a surf board or body board, the invention may allow tighter turns and increased "sticking" to the wave face.

In Figure 8 a bottom perspective view seen of a rear portion 50 of a water craft.

The rear portion 50 has three channels 51, 52, 53, respectively. The side two channels 51, 53 are formed as previously described with forward and lateral intakes, and intermediate throat and rearward and lateral discharges.

The intermediate channel 52 does not have any lateral intake, it does have a ramped intake 54 directed forwardly. The throat 55 is position intermediate the forward ramp 54 and rearward outlet 56 which discharges directly astern. The intermediate channel 52 is positioned with its midline coincident with a longitudinal midline of the water craft.

-12- Figure 9 shows the arrangement of Figure 8 in a surf board 57. The intermediate channel 52 is again apparent along a longitudinal midline of the surf board while the side channels 51, 53 are positioned outwardly as previously described.

Throughout the specification the aim has been to describe the preferred embodiments of the invention without limiting the invention to any one embodiment or specific collection of features. Those of skill in the art will therefore appreciate that, in light of the instant disclosure, various modifications and changes can be made in the particular embodiments exemplified without departing from the scope of the present invention. All such modifications and changes are intended to be included within the scope of the disclosure.

Claims (39)

1. A water craft comprising: a top deck; a side wall continuous with the top deck; a bottom surface continuous with the side wall; and at least one channel in the bottom surface, said channel comprising a forward intake section, a rearward discharge section and a throat section intermediate and narrower than the intake section and the discharge section.

2. The water craft of claim 1 wherein the at least one channel creates a venturi effect during water flow therethrough.

3. The water craft of either one of claim 1 or claim 2 wherein the at least one channel has a side wall that is curved in cross section.

4. The water craft of either one of claim 1 or claim 2 wherein the at least one channel has a cross sectional shape with at least two walls angularly disposed to each other.

The water craft of claim 1 including two channels.

6. The water craft of claim 5 wherein the two channels are each located adjacent respective lateral side wall of the water craft.

7. The water craft of any one of the preceding claims wherein the intake section opens both forwardly and laterally.

8. The water craft of any one of the preceding claims wherein the intake section abutts or includes a forwardly directed ramp.

9. The water craft of any one of the preceding claims wherein the discharge -14- section opens at least partially laterally.

The water craft of claim 9 wherein each channel includes one or more fins mounted therein.

11. The water craft of claim 10 wherein the one or more fins are mounted centrally in the channel.

12. The water craft of claim 11 wherein the one or more fins are entirely enclosed within a space of the channel.

13. The water craft of claim 11 wherein the at least one of the one or more fins protrudes beyond the space of the channel.

14. The water craft of claim 10 wherein the one or more fins are positioned centrally in the throat section of the one or more channels.

The water craft of any one of the preceding claims wherein the water craft is a surf board.

16. The water craft of any one of claims 1 to 14 wherein the water craft is a kayak.

17. The water craft of any one of claims 1 to 14 wherein the water craft is a surf ski.

18. The water craft of any one of claims 1 to 14 wherein the water craft is a jet ski or other powered vessel.

19. The water craft of any one of claims 1 to 14 wherein the water craft is a body board.

The water craft of any one of the preceding claims comprising three or more channels.

21. The body board of claim 19 wherein the top deck includes a back support means.

22. The body board of claim 21 wherein the back support means is a lumbar support means.

23. The body board of claim 22 wherein the lumbar support means comprises a lumbar flexion-inducing ridge.

24. The body board of claim 23 further comprising a chest recess forward of the lumbar flexion-inducing ridge.

The body board of claim 24 further comprising a chin support structure.

26. The body board of the claim 25 further comprising paired fairings each located to a respective side and outwardly of a longitudinal axis of the body board.

27. The body board of claim 26 further comprising hand recesses located adjacent the fairings.

28. The body board of any one of claims 20 to 27 wherein an outer perimeter of the body board defines an anterior section and a tail section wherein the tail section is narrower than the anterior section.

29. The body board of claim 28 wherein the tail section further comprises a scalloped rear wall.

The body board of claim 29 wherein the scalloped rear wall has a forwardly sloping angle. -16-

31. The body board of claim 30 wherein the anterior section has convexly curved side walls.

32. The body board of claim 31 wherein the tail section has side walls which are substantially parallel.

33. A water craft including at least one channel in its wetted area, said channel comprising a forward intake section, a rearward discharge section and throat section intermediate and narrower than the intake and discharge section.

34. The water craft of claim 32 wherein the at least one channel provides a venturi effect during water flow therethrough.

35. A method of providing directional control in a water craft, said method comprising the steps of: forming at least one channel in a bottom of the water craft, said channel having a forward intake section, a rearward discharge section and a throat section intermediate and narrower than the intake section and discharge section.

36. The method of claim 35 further including the step of forming two channels in the bottom of the water craft, each of the channels adjacent or in the general region of a respective side wall of the water craft.

37. The method of claim 36 further comprising the step of positioning the forward intake section with at least a part of the intake section opening laterally in the side wall.

38. The method of claim 37 further comprising the step of positioning the rearward discharge section at least part of the discharge section opening laterally.

39. The method of any one of claims 35 to 38 further comprising the step of -17- adding a third channel. A water craft substantially as herein described with reference to the accompanying figures. DATED this 11 th day of June, 2003 Glen Cyril Elliot Solly by DAVIES COLLISON CAVE Patent Attorneys for the Applicants