GB2547192A

GB2547192A - A system for creating an obstacle in a water flow

Info

Publication number: GB2547192A
Application number: GB1602252.7A
Authority: GB
Inventors: Laird Andrew
Original assignee: Eng Paddler Designs Ltd
Current assignee: Eng Paddler Designs Ltd
Priority date: 2016-02-08
Filing date: 2016-02-08
Publication date: 2017-08-16
Also published as: GB201602252D0

Abstract

The present application is directed at providing an obstacle 1 for use in a white water course or similar environment for surfing, stand up paddle boarding, kayaking, canoeing or rafting. The obstacle may be used to form a wave which may be surfed by surfers on surfboards or the like. The obstacle has a ramp section (2 figure 2) which defines a water flow engaging surface. The shape or angle of the ramp is set at least in part by the amount of fluid in a reservoir of an expandable element (10 figure 1). Later embodiments relate to a method of installing a water flow obstacle, an obstacle for installing in a water flow, and a wave feature installed in a water flow.

Description

A SYSTEM FOR CREATING AN OBSTACLE IN A WATER FLOW Field of the Application

The present application relates to devices and systems for forming an obstacle in a water flow.

Background

White water sports are increasingly becoming popular, with surfing, stand up paddle boarding, kayaking, canoeing, rafting and river boogie boarding being amongst the most popular. The term white water implies that the water is flowing and that there are rapids or obstructions that present irregular features on the water surface to the participant.

Four factors, either separately or in combination, can create features in a rapid: gradient, constriction, obstruction and flow rate. Gradient is defined by the general topography and does not generally change. Similarly, constriction and obstruction tend to be relatively consistent in a given topography. As a result, normally the general form of a feature is only affected by flow rate. It will be appreciated that a number of factors may cause changes in flow rate including natural factors such as precipitation and man-made factors such as flow release for example where a river is dam controlled. Examples of water features include hydraulics (also known as holes and stoppers), waves, pillows and eddies. It will be appreciated that the water feature arises from and is part of the flow of wafer. The water feature is distinct from the topography that causes it. For white water sports participants, the enjoyment to be gained from an individual feature or combination of features depends on the particular form of a water feature. If is not uncommon for example for a water feature such as a wave to be extremely popular with participants at one particular water flow and of no interest at other water flows. Equally, a water feature may be extremely dangerous at one water flow and perfectly safe at another. Accordingly, it is generally desirable to be able to alter the water flow to achieve a desired form of a feature. However, it will be appreciated that this is only possible in limited circumstances, for example where a river is dam controlled. Even where a river is dam controlled, the water flow may be dictated by electricity needs from generation or water supply for drinking and outside of the control of white water sports participants. Similarly, whilst changing the water flow may be desirable to improve the form of one water feature it may ruin other water features in the river.

Whilst in a natural river or tidal flow, the factors of gradient, constriction and obstruction are generally predetermined, it is known to alter the underlying or surrounding topology to alter the associated feature being formed. A simple technique is to add obstacles, e.g. boulders to the water flow to reconfigure or indeed create a water feature. In artificial white water courses, the entire bed and banks of the river may be shaped in concrete to achieve a desired set of sequential water features in the form of a rapid.

Other approaches are known, where obstacles may be installed and repositioned to alter the features in a rapid. An example of such a system is described in EP2417301 which shares a common inventor with the present application and allows for the installation of assemblies of obstacles which may be used to increase the amplitude of a feature, speed up water flow, change depth, etc. This system was used in the white water course in the London Olympics.

The present application is directed at a different approach to altering or creating a feature in a water flow.

Summary

The present application is directed at an obstacle which may be installed in a water flow to create a water feature.

More particularly, the present application is directed at an obstacle generally in the form of a ramp. The ramp when positioned in a flow is intended to result in the generation of a wave like feature. The obstacle disclosed in the present application is relatively inexpensive and may be adjusted whilst in situ.

Brief Description of The Drawings

Figure 1 is a perspective view of an obstacle for use in forming a feature in a water flow;

Figure 2 is a top view of the obstacle of Figure 1 positioned in the channel of a river;

Figure 3 is a cross sectional view corresponding to Figure 2;

Figure 4 is a side view of the obstacle of Figure 1 illustrating the collapsible nature of an expandable section of the obstacle;

Figure 5 is an exemplary arrangement of expandable circular cross sectional elements which are arranged to provide an expandable section;

Figure 6 is an exemplary tiered arrangement of expandable rectangular cross sectional elements which are arranged to provide an expandable section;

Figure 7 is an exemplary tiered arrangement of expandable and non-expandable rectangular cross sectional elements which are arranged together to provide an expandable section;

Figure 8 is a side view of two adjacent expandable elements fastened together; Figure 9 is a cross sectional view of an expandable section formed using a drop stitch construction;

Figure 10 is a side view of an obstacle, showing a ramp section made up of three inflatable elements.

Figure 11 is a top view of a first configuration of a tier of expandable elements in a river channel;

Figure 12 is a top view of a second configuration of a tier of expandable elements in a river channel;

Figure 13 is a top view of a third configuration of a tier of expandable elements in a river channel;

Figure 14 is an exemplary system for inflating/deflating expandable elements; Figure 15 is an exemplary installation including an obstacle of the type generally shown in Figure 1;

Figure 16 is a side view of a downstream part of the installation of Figure 15 showing jack cells, a wave face cell and a base;

Figure 17 is a detailed partial view of the base from Figure 16; and

Figure 18 is a view of an upstream part of the installation from Figure 15 constructed using expandable and non-expandable rectangular elements.

Detailed Description

The description which is presented below is for purposes of illustration and description. It is not intended to be exhaustive or to limit the claims to the precise form disclosed, and other modifications and variation may be possible in light of the above teachings. The examples were chosen and described in order to best explain the principles of the obstacle and its practical applications to thereby enable others skilled in the art to best utilize the concepts associated with the obstacle in various forms and various modifications as are suited to the particular use contemplated. It is intended that the appended claims be construed to include other alternative constructions except insofar as limited by the prior art.

The obstacle of the present application employs expandable (inflatable) sections to form a feature in a flow of water. The shape of the obstacle may be altered by altering the extent to which the expandable section(s) are filled with water. The expandable sections may be employed to form a base, a wave face or to angle the wave face with respect to the base by acting as a jack below the wave face. Accordingly, the sections may be referred to as base sections, wave face sections or jack sections.

The obstacle of the present application may be deployed in a variety of different situations to form a wave or wave like feature in a water flow. For example, it may be employed in a river (natural or man-made), a tidal race or in a situation where pumps are employed to force water flow. However, for the context of explaining the nature of the obstacle, reference will be made to its exemplary deployment in a river. Accordingly the discussion which follows will employ terms associated with a river such as river banks, river channel and river bed which are useful for the purposes of explanation but which are not to be construed as limiting.

As will be appreciated from the description which follows, the obstacle of the present application may be readily installed in a river channel to create a wave like feature. The obstacle may be generally considered to be a ramp like obstacle which changes the angle of the flow with respect to the river bed. In a typical configuration, the ramp urges the flow of the river upward from the river bed.

It will be understood, that generally river banks constrain the flow of water to a channel and so if a ramp is placed in the channel, the water being generally constrained will flow over it although as will be explained further on, it is beneficial to place the ramp facing upstream at a point after where the river bed has effectively dropped in height where the speed of the flow would be faster.

After installation, the shape of the obstacle may be adjusted. Similarly, the obstacle may be readily removed. This temporary and variable nature of installation has significant advantages over the conventional approach of using a permanent material such as concrete.

The exemplary obstacle 1, as shown in Figure 1, has an upper surface 2 which is arranged at an incline to the bottom of the obstacle so as to form a ramp when placed on a surface such as the bed of a river.

The ramp may be positioned in a river channel 20 between two river banks 22, 24, as shown in Figure 2, to cause the formation of a wave or stopper in a water flow 25 as shown in Figure 3 which in turn may be surfed by a person 30 in a suitable water craft, such as a kayak or surfboard. As an example, the obstacle may be employed in an artificial white water course designed for kayaking to provide a wave feature more suited to surfers, body boarders or stand up paddle boarders.

The upper surface extends in a direction parallel with the banks of the river channel between a leading edge 6 and a trailing edge 16. The leading edge is intended to face upstream in a channel and generally present a low profile to an oncoming water flow 25. Suitably, the leading edge 6 may be anchored to the river bed or to structures fixed within the channel or to the banks.

In the case of an artificial white water course for example, bolts, rings or other such fixings may be provided in the river bed to which the leading edge 6 or other part of the ramp 2, may be fixed or fastened.

The leading edge 6 for example may have apertures defined therein which may be placed over bolts fixed in the river bed 8 allowing the leading edge 6 to be fixed in place my means of conventional nuts and washers. Similarly, the leading edge 6 may have anchors provided thereon, e.g. D rings allowing for the leading edge to be tethered or clipped by means of ropes, webbing, or metal connectors such as carabiners to co-operating features provided on the river bed 8, banks or another feature positioned in the river. As an example, scaffolding may be installed in the river adjacent to each bank on to which parts of the obstacle may be fixed.

Similarly, the leading edge 6 may be formed to define a passage 14 from one side to the other, for example as a folded and sewn section, through which a rope or similar, may be passed through to tether or secure the obstacle, as shown in Figure 1. As an example, a scaffolding or similar metal bar may be passed through the passage and secured to a scaffolding or other structure to retain the obstacle in position.

Also shown in Figure 1 are inlets 4 for filling an internal reservoir, which will be described in further detail below.

The opposing sides 17, 18 of the obstacle are intended to be positioned parallel to and adjacent respective opposing banks of the river 22, 24. In certain situations, the banks of the river may be extended outward using other obstacles to narrow the effective width of the channel. For, example using arrangements of blocks described in EP2417301, opposing walls may be constructed parallel and adjacent to respective banks of the river to form artificial banks which narrow the effective river channel. The obstacle 1 of the present application may be installed in the narrowed channel between the respective artificial banks.

The upper (water flow engaging) surface 2 of the obstacle is intended to present a ramp like feature to water flowing in a channel. Alternatively stated, the upper surface of the obstacle is intended to present an inclined surface relative to the horizontal.

The function of the ramp section is to direct the water flow generally upwards away from the river bed so as to form a wave or other water feature.

In contrast to previous approaches which, for example, used concrete structures or similar solid installations, the approach to providing an obstacle described present application allows significant flexibility with respect to installation, removal and allows for the shape of the obstacle to be adjusted in situ.

This flexibility with respect to installation, removal and adjustment, is provided by an expandable section 10, which is provided generally below the upper surface 2 of the ramp. This expandable section acts as a jack to raise up one end of the ramp with respect to the other end. Thus for example, the downstream end of the obstacle may be raised with respect to the upstream end.

As shown in Figure 4, the angle of the ramp a may be changed, for example as shown to a by altering (in the example shown by reducing) the degree to which the expandable section 10 is expanded. Thus the angle of inclination of the ramp may be adjusted with respect to a river bed or other support on which the obstacle is placed. The angle of a ramp plays a significant part in the defining a water feature (e.g. wave) by adjusting the extent to which the expandable section is expanded, the shape of the water feature may be altered to achieve a desired effect.

The expandable section 10 may be generally wedge shaped with the narrow end of the wedge being positioned toward the leading edge 6 of the upper surface 2 and the wide angle of the wedge being positioned toward the trailing edge 16 of the upper surface.

To facilitate the expansion\collapse of the expandable section, the expandable section is constructed using at least one expandable element, which in turn defines at least one reservoir for holding a fluid. An inlet 4 is provided to allow for filling of the expandable element. The inlet may also be used for emptying the expandable element or a separate outlet (not shown) may be provided to facilitate emptying of the expandable element. The expandable element is expandable from a collapsed state to an expanded state by filling the at least one reservoir.

The nature of the expandable element is that of an inflatable structure, e.g. as employed in watercraft such as rafts, inflatable surfboards, airbeds etc formed using a rubber, vinyl or similar flexible, waterproof material.

It will be appreciated that the expandable element is acting as a jack, increasing or decreasing the angle of incline generally of the ramp as required. Accordingly the expandable elements may be considered as jack cells which co-operate together to act as a jack for the purposes of jacking the ramp as required.

Accordingly as each jack cell is progressively filled with fluid, the angle of the ramp generally increases. Similarly, the angle of ramp may be decreased by emptying of the jack cells.

Whilst a gas, such as air, might be used as a fluid to inflate the expandable (inflatable) sections/elements, it will be appreciated that employing a gas means that the obstacle would be inherently buoyant requiring significant additional fastenings to retain it in place securely under the water flow. By employing a liquid, such as water, to inflate the expandable structure the buoyancy of the obstacle is significantly reduced. A valve may be provided at the fluid inlet to allow the reservoir to be filled to a desired fill level and then closed off to maintain the shape of the expandable element.

To facilitate adjustment (filling/emptying) of the expandable element in situ to dynamically adjust a water feature to have a desired form, a pipe or hose may be used to extend from a first end at the inlet to a second end where in turn a valve may be provided allowing for the the reservoir to be filled or emptied through the hose/pipe. The advantage of this approach is that the shape of the obstacle may be adjusted as required.

Accordingly, in use, the ramp section presents a surface which is inclined at an angle with respect to the river bed. The angle of the ramp may be, set at least in part, by the amount of fluid in the reservoir of the expandable section. Thus by only partially inflating the expandable section with fluid, a less steep ramp may be provided as shown in Figure 4 with the dashed outline.

The expandable section 10 may be provided using a single expandable section, for example wedge shaped expandable section.

The expandable element may be formed using techniques employed for making inflatable lilos, mattresses, the inflatable sections of RIB’s, inflatable rafts, inflatable surfboards and similar structures. It will be appreciated that these are generally constructed using an outer covering of vinyl or similar type material.

The wedge shaped nature of the expandable element may be defined generally by constraining structures provided within the element to restrict its shape as would be familiar to those skilled in the art.

In the inflated state the cross sectional shape of the expandable inflatable section is generally a wedge. As fluid is emptied from the element, the angle of the wedge decreases to the point where when the element is emptied, the element is generally flat. Thus when emptied in situ in a water flow, the low profile of the leading edge and the flat nature of the emptied expandable section has the result that no obstruction of significance (compared to the expanded wedge shape) is presented to the water flow. This has the advantage that it may be left in situ without interfering with the water flow when a wave like feature is not required. Thus for example, the obstacle may be filled with water when required to produce a wave for surfing and emptied to allow for use of the river by rafts or slalom kayakers where a wave of this nature might be less desirable.

Similarly, as the element is formed from a flexible material it may, when empty (in the collapsed state) be removed and folded or rolled up for transport or storage as required. The obstacle may also comprise straps in order to retain the obstacle rolled up.

The adjustability of the angle of the ramp provides for the creation of different water features. As an example, a lower angle is more likely to provide a more laminar flow resulting in a green wave where there is no white water. In contrast, as the angle of the ramp is increased, it is more likely to produce a white water (foaming) wave.

In contrast to previous approaches using rigid assemblies or constructions, the amount of fluid in the reservoir may be adjusted until a desired form of water feature is formed.

The expandable section 10 may be made up using a single expandable element, such as the wedge shape shown in Figure 1.

However, it may be preferable to employ multiple expandable elements 12 to define the expandable section 10. In this arrangement, each expandable element 12 may have a reservoir. Equally, each expandable element may have an associated inlet 4 for filling or emptying their reservoir with fluid. An example of multiple expandable elements 12 is shown in Figure 5 of the drawings.

In such an arrangement employing multiple expandable elements 12, the overall shape of the elements may combine together to define a wedge like shape. The use of a plurality of expandable elements provides a number of advantages including for example, greater flexibility in forming a desired shape. Since the number of elements may be varied to lengthen or widen a ramp as required.

Additionally, it allows for a ramp to be constructed where the top surface of the ramp is not planar but instead presents a slightly curved surface, more generally resembling the curve of a wave face.

Similarly using multiple inflatable/expandable sections may allow for a better definition of the shape of a ramp. Alternatively stated, the shape of a wedge with a single element may only be present when the reservoir of the single element is filled completely and may lack structure/rigidity when only partially filled. This could result in a ramp that lacks shape, i.e. it loses its wedge shape and is more generally flat, or it might for example wobble creating a nonstable water feature.

By using a plurality of expandable sections, different sections may be filled at a time, with other expandable sections left empty or partially filled thus providing an overall more stable shape.

It will be appreciated that in the absence of features constraining the shape of an expandable section, such inflatable structures will generally tend to form a circular cross section, i.e. a tube. An exemplary arrangement using such tubes is shown in Figure 5. In this arrangement a combination of expandable tubes 12 combine together to generally support the upper surface 2 and define a wedge shape. In the arrangement, shown a combination of tubes with different radii is shown, but equally tubes with a common radius may be employed.

However, using such a construction of expandable elements 12 in the form of tubes, it may be difficult to vary the shape of the ramp as desired.

An alternative approach, shown in Figure 6, is to employ expandable elements 12 which are of generally rectangular cross section in their expanded state. In the exemplary arrangement of Figure 6, a plurality of inflatable elements (cells) 12 with a generally rectangular cross section are arranged in a tiered structure. Each tier in the structure may comprise one or more expandable elements 12. Thus in the exemplary tiered structure shown, the bottom tier comprises three expandable elements and the top tier comprises a single tiered element 12.

Also shown in Figure 5 (as well as Figures 6 and 7) are a passage 14, and a flap 42, which will be described in further detail below.

As with the tubular sections of Figure 5, the cross sectional dimensions of the rectangular elements may vary from one element to another. Although, suitably the height of expandable elements in the same tier are the same so that the height of the tier is generally the same to facilitate ease of assembly and stability of the structure. However, the last cell in a tier adjacent to the ramp may be a reduced height. In this way, as shown in the upstream ramp of Figure 15, the end cell and the next to end cell in a tier may both contact and support the ramp surface directly.

As the tiers extend from the base tier to the top tier, the overall length of the individual tier reduces so as to define the generally wedge shape of the expandable section.

In one arrangement, the expandable section is formed entirely of expandable elements. In another arrangement, the expandable section comprises a mixture of non-expandable and expandable elements. Thus as shown in Figure 7, there are a plurality of non-expandable elements 26 which may for example be formed in-situ or may be of the type previously referenced above in EP2417301 which co-operate together to define the underlying support for the upper surface of the ramp 2. A base structure 13, shown in Figure 7, may be provided which is fixed in place and to which the elements 12 of the expandable section and upper surface 2 are fastened. However, equally the elements may be directly secured/attached to the river bed or bank of an artificial water course.

The use of inflatable elements made with restraining features, for example by using drop-stitch material construction (described below) in fabricating the expandable elements, allows for an easy stacking of the inflatable sections when inflated/expanded as they maintain their generally rectangular shape. In this context, the expandable elements might initially be inflated with air to facilitate ease of building and positioning the structure. This is particularly the case in the situation of an artificial white water course where it is possible to turn off the water flow. In this situation, the expandable sections may be moved into place whilst filled with air, fixed in situ, deflated and then re-filled as required with water.

Different sizes (i.e. the length, diameter or thickness may be different) of expandable elements may be used. For example the base tier may be made up of elements of one size and the top tier of the section being made up by smaller sized expandable elements.

The expandable elements/cells may be of any suitable dimensions depending on the requirements of a particular application, for example the site and use required for the obstacle. Equally, the dimensions may vary depending on the particular use of the expandable element i.e. whether the cell is one or part of a jacking cell, base, crash mat (described below) or ramp cell.

However for ease of constructions and assembly and use of the obstacle, it has been found that employing expandable elements for the jacking cells having a length in the range of ,5m to 5m and more suitably in the range .75 to 2m is desirable. A 1m length represents a size which may be easily manufactured using available materials. At the same time, the width of the jacking cells may be in the range of 10cm to 60cm and more preferably between 20cm and 40cm wide. It will be appreciated that the lengths and widths are relative to one and other as the cells may be installed in line with the river channel or transverse thereto.

The cells making up the ramp, base and crash mat (described below) will tend to be larger in surface area and flatter than the jacking cells. Thus for these elements, both the lengths and widths may be in the range of ,5m to 10m. Although for manufacturability one of either the length or width may be limited to 3m or less and suitable less than 2m and conveniently about 1m. At the same time, similar thicknesses to those used for the jacking cells may be employed, for example generally between 5cm and 40cm, although again most suitably between 7cm and 25cm.

Similarly, the ramp section may be in the range of .5 m to 2 m, however more preferably in the range of 1m to 1.5 m. The exemplary arrangement in Figure 6 shows a ramp section of 1.4 m length and 1 m width.

The expandable base section 13 may be in the range of 1m to 3m, preferably however in a range of 1.5 m to 2 m. Figure 7 shows an exemplary embodiment of the base section, wherein the length of the base section is 1.95 m and the width is 1 m.

The expandable elements are suitably configured to be fastenable to one and other to retain the overall structure of the obstacle together. In one arrangement, the expandable elements are provided with fasteners allowing adjacent sections to be fastened to one and other.

For example, the sections may be provided with co-operating zip sections along their lengths allowing for adjacent sections to be zipped together.

Similarly, co-operating clips and rings may be provided allowing for adjacent sections to be clipped together. An example of such an arrangement is shown in Figure 8, where rings are provided at the corners of adjacent expandable section 10 allowing for adjacent sections to be readily clipped or tied together using a clip 44 or rope 44.

Similarly, intermediate rings may be provided at mid points on the top or bottom surfaces of the expandable elements allowing for connections to elements in the tier above or below.

The expandable elements may also be provided with flaps 42 with loop and hook fasteners like VELCRO™, extending from and along at least one of the edges of the expandable element as well as suitable along the surface of the expandable element (to attach the flap to it). An exemplary flap 42 is shown in Figure 8.

The rectangular cross sections may be achieved using constraining features which constrain the shape of the expandable section when expanded. Techniques for providing such constraining features will be familiar to those skilled in the art and employed for example in air mattresses and inflatable surfboards.

One constraining method for forming a generally rectangular cross sectional shaped (or indeed other shapes) in an expandable element, is to employ a drop-stitch construction. Drop-stitch constructions are made from two pieces of material, for example polyester, which are sewn together using threads, suitably polyester. The threads are generally evenly spaced and form a tight bond between the two pieces of material. Where parallel surfaces are required, the length of the individual threads is selected to be the same. By graduating the lengths alternative shapes are possible. The advantage of employing a drop stitch construction is that the resulting material gives a high degree of stiffness while being very light-weight.

An example of such a structure is shown in Figure 9 which shows an exemplary expandable element (cell) where the distance between the top and bottom surfaces are constrained by internal threads joining the top and bottom surfaces. The tight bond enables the material to be inflated/expanded to high pressure without losing its original shape and it prevents bulging of the structure as would be the case for example when using simpler inflatable panels.

The upper surface of the obstacle may be provided by a flexible cover which is stretched over and covers the expandable section below. One or more resilient tethers (e.g. elastic ropes) may be employed to ensure the surface remains stretched regardless of the extent of expansion of the expandable section below. An advantage of using a flexible upper surface is that the risk of injury to a surfer surfing the water above the ramp is reduced when they fall and similarly the risk of injury to a kayaker capsizing is reduced since they will not be contacting a rigid surface.

Similarly, the upper surface of the obstacle might be formed using a relatively rigid material, for example, plywood. Although, this is less desirable as it may injure a falling surfer or capsizing kayaker.

The upper surface of the obstacle may also be formed using one or more expandable elements of the type generally described above.

An advantage of forming the upper surface of the ramp using an expandable section is that inflating such an expandable section with fluid provides a degree of rigidity in the context of forming the water feature. Thus the upper surface of the ramp will be generally smooth and regular. At the same time, a falling surfer or capsizing kayaker is cushioned on contact.

It will be appreciated that using an expandable element of the type previously described to form the contact surface of a water obstacle has inherent advantages, not only such as the cushioning effect when employed on its own without the underlying expandable section, but also in relation to the flexibility of the obstacle, which will be further discussed below.

Accordingly, a contact surface formed from one or more expandable elements as described above might, for example, be employed in conjunction with a more conventional wave forming structure underneath. For example, a concrete or plywood construction might be employed to generally define the shape of a wave feature with an expandable section provided thereon as the contact (upper) surface to reduce the risk of injury to a surfer or kayaker surfing the wave formed. Similarly, an underlying ramp support structure could potentially be avoided altogether by suspending a ramp surface formed using an expandable element or elements suspended between the river bed at the leading edge and the top of the banks from the trailing edge. However, it will be appreciated that the forces exerted in this situation by the flow of water would be significant. Accordingly, this approach may only be suitable for narrow wave features where the width or length of the ramp or both is relatively small.

As previously discussed, the obstacle may be made up of a plurality of different expandable sections. It will be appreciated that expandable sections may be combined with non-expandable sections. Thus for example, as explained above part of the obstacle may be formed using rigid obstacles, for example of the type known as Rapid Blocs to form a base for the ramp, for example as a series of steps on which the expandable sections may then be placed.

To present generally laminar surface to the water flowing over and along the obstacle, where two surfaces abut, for example where the ramp abuts the base or one expandable element forming the ramp abuts another expandable element for the ramp, a flap of material may be provided extending from one surface to cover at least the edge of the next.

Using a flap of material covers the gap between the surfaces thus maintaining a laminar flow. At the same time, it reduces the risk of the water flow entering the gap between the surfaces and forcing them apart. Indeed it will be appreciated that a flap with a suitable fastener may be used to fix surfaces (e.g. expandable sections) together.

The flap may be integrally formed on one of the surfaces with a fastener used to fasten the flap to a second surface. Alternatively, the flap may be formed separate to both surfaces and fasteners used to fasten the flap to both surfaces.

In both cases the fastener may for example be a hook and loop type fastener (Velcro) formed by co-operating elements on each of the surface and flap.

As mentioned above, the upper surface may also be made up of a plurality of expandable elements 36, 38, 40. An example is illustrated in Figure 10 in which three expandable elements (cells) are employed to create the ramp surface. The plurality of expandable elements may be co-formed as one unit, but with separate inlet 4 for each so that the user can fill/empty different elements making up the surface of the ramp. This provides greater flexibility in adjusting the wave shape.

Thus as shown in Figure 10, the intermediate 38 of the three ramp cells is deflated relative to the leading cell and trailing cell. As a result, the intermediate strength will be more flexible. Accordingly, when water flows over the obstacle, the ramp surface will deform to be generally concave in shape. Such a concave shape may be generally preferred by body boarders and surfers on short surf boards. In contrast where the wave is desired for use by a longer board (e.g. a stand up paddle board), the leading and trailing edges may be deflated relative to the intermediate section so that the intermediate section bulges with respect to the others, i.e. forming a more generally convex shape. To provide a smooth transition between the expanded and deflated elements, flaps 42, as described above, may be provided at the transition ridge of the elements. The flaps may join the adjoining cells on the top surface. It will be appreciated that the use of flaps allows for different degrees of inflation between adjoin surfaces. The adjoining cells may be fastened directly to each other, i.e. without a flap, at the bottom of the cells. Similarly, it will be appreciated that it may not be desirable to form a fixed connection between the jacking cells and the ramp cells on top of them so to as allow for relative movement between them. This reduces the potential need to re-adjust fasteners as cells are inflated/deflated.

Accordingly, an expandable ramp section may be pivotably connected at one end to an anchoring point with the ramp free to pivot about that point. Thus the ramp incline may be raised or lowered by filling or emptying of the jacking cells. It will be appreciated that the water flow will generally force the ramp surface onto the jacking cells.

In a further example, the plurality of individual expandable elements of the ramp may also be connected via a common shared base. The base may be made of the same material as the expandable elements. A shared base may provide additional support and allow for a variety of different elements to be provided together onto a common base as will be described below in the context of Figure 15.

Equally, in the arrangements described above, the expandable elements 12 are explained as generally extending in a longitudinal direction transverse to the flow of the river, i.e. as shown in the exemplary tier in Figure 11, the elements extend generally from one bank of the river 22 to the other bank 24. However, the expandable elements 12 may also be aligned in parallel with the river flow as shown in the arrangement of an exemplary tier of such sections shown in Figure 12 where each expandable element extends in a longitudinal direction from side of the obstacle to the other as shown from one bank to the other.

Equally, a combination of these approaches may be used. Thus as shown in the exemplary tier in Figure 13, a first group 32 of expandable sections combine together to extend from one side of the obstacle to the other. A second group 34 of expandable sections are shown extending from the leading edge of the tier to a leading edge of the first group. It will be appreciated that various combinations are possible to define a particular required shape for a tier in the ramp or for the ramp itself. Thus to extend the width of the ramp, a plurality of inflatable sections may be required and may be arranged in at least one group, wherein the inflatable sections of the group extend from the first side to the second side. This however makes it possible to slant the ramp from one (side) bank to the other. Thus the height of one side of the trailing edge of the obstacle may be selected to be higher than that of the opposing second trailing edge.

It will be appreciated that using such an approach the shape of the ramp is entirely configurable and may be configured in situ. As an example, surfers generally like to surf to the side of the breaking part of the wave. By varying the steepness/shape of the obstacle from one side of the river to the other, a wave may be formed which breaks on one side and is green on the other. Moreover, this may readily be switched by switching the extent of filling from the expandable elements to the other side. Thus a surfer might have a favourite side for a breaking wave (referred to generally as left break or right break). In a competition, this advantage could be eliminated by switching the direction of the break in successive rounds.

An exemplary arrangement for filling/emptying the expandable sections is shown in Figure 14. The exemplary arrangement comprises five expandable elements 12, however it will be appreciated that this may readily be adjusted to account for the number of expandable cells. Equally, the expandable cells, may be ramp or jack cells or a base or a crash mat or a combination of these. Each expandable element is connected by a pipe or hose 36 to a valve 38. The valves in turn are commonly connected to a pump 40. The pump is suitably bidirectional to allow filling or emptying. By selecting the pump direction (using for example an electrical switch (or valve arrangement), the expandable elements may be filled or emptied by appropriate selection (opening/closing) of their associated valve. The arrangement may be manually controlled or may be automated. It will be appreciated that in the case of an automated control system, a controller may be used to control the pump and valves. In such an arrangement, the controller may have different configurations pre-stored. Each configuration may represent a different combination of filled and empty cells or may specify a percentage or volume fill for individual cells. In this way, a user can select by an appropriate interface to the controller a desired configuration. Similarly, the interface, may allow a user to request a particular shape, type or size of wave from which the controller determines the extent to which the individual expandable sections are filled or emptied as required.

An exemplary installation employing a combination of the previously described obstacles to create a wave feature is presented in Figure 15 with individual aspects shown in greater detail in Figures 16 to 18. In this arrangement, a wall is provided at the upstream side of the installation. This wall may be constructed using the previously described elements in EP2417301. This wall acts a weir building up the height of the water behind. A first ramp 46 of the type generally described above is provided extending downstream from the wall. In contrast to the earlier description, the ramp faces downstream. This ramp does not form the wave feature as such but instead improves the wave formed on a successive second ramp by causing the acceleration of the water flow in a laminar fashion. The second ramp 2 is positioned downstream of the first ramp and the wave is formed generally above this ramp. It will be appreciated that the first ramp 46 is formed without a base structure, i.e. there are merely the jacking cells 12 and the ramp cell(s). In contrast, the second ramp is formed on a base section 13 that extends up to the end of the first ramp. In the exemplary arrangement shown, the base section 13 is formed with a leading edge having a pocket 14 formed which as described above in the context of an exemplary ramp may be used to tether the base to support structures. In the exemplary arrangement, the pocket 14 receives a bar, e.g. a scaffold or similar type bar, which in turn is fixed to the river banks or other structure including the river bed. In this arrangement, the support bar performs the task of holding the base and thus the second ramp in situ, although additional fixings may be employed. It will be appreciated that a second bar may be used in a similar manner to fix the end of the first ramp is situ. The bars employed may be of a rectangular profile, e.g. 40mm x 60mm. An advantage of using such a profile is that the co-operating holes may be defined in the sleeve and bars allowing the bars from the upstream and downstream sections to be readily clamped together using bolts. Equally, the bars may also be fastened using bolts to the river channel.

In the particular example shown, the leading section of the first ramp 46 is held in situ by loops extending from it in a generally upstream direction. These loops 48 may be fixed around the top part (blocks) of the wall as shown in the more detailed Figure 18.

To facilitate the connection and integration of pipes to and from cells, the inlet/outlet for individual cells may be provided at a side or front or rear face. In the arrangements of Figure 16, the inlets 4 are generally shown as being to the front or rear faces. The advantage of this approach is that where several cells are required to bridge from one side of the river to the other, the pipework coming from one cell is not generally obstructed by an adjacent cell. A cushion section 28, shown in Figure 15, is provided on the downstream side of the second ramp. This cushion, section acts as a crash mat to cushion the impact to any surfer or kayaker who falls off the wave and drops onto the backside of the obstacle. In contrast, existing wave forming structures tend to be unforgiving with no consideration paid to the following section after the wave leading to injuries. The cushion or crash mat section which extends downstream from the obstacle may also be formed from one or more expandable elements previously described.

It will be appreciated that the ramp section will cover and thus protect most inlets/pipes for the underlying base and jack cells and similarly flaps of the type previously described may be employed to cover pipework to ramp cells.

However where pipework exits at the rear of a ramp, an elastic cover may be provided, e.g. extending from the ramp to the crash mat to prevent a surfer accidentally catching their hand or similar on the pipework.

The expandable elements described herein may be provided with a pressure relief valve for releasing fluid from the reservoir in the event of excessive pressure. The use of a pressure relief valve reduces the risk of an expandable element bursting, for example when a surfer falls heavily upon the ramp.

Figure 17 shows a view of the leading edge of the base of Figure 15. The leading edge may be provided with a flap which forms a passage 14. The passage may be used to hold a rope or scaffold bar for anchoring the base to a river bed. Alternatively, holes 48 may be provided in the flap which may be used to secure the base to the river bed. Screws but also a rope may be used to secure the base to the river bed, using the flap.

The flap may extend along the length of the leading edge of the base.

Using the previously described measurements of the base section 13, the length of the flap accordingly may be between ,5m to 5m and more suitably ,75m to 2m. However, as the size of the expandable cell most easily to manufacture is 1 m, the length of the flap may also be 1. The width of the flap may be of any suitable dimension to extend across and beyond the gap between adjacent cells but is suitably in a range between ,1m and ,75m.

In the exemplary arrangement shown in Figures 15 onwards, for the downstream wave forming obstacle, the jack cells, base and wave face cell are each 20cm thick, the length of the base is 195cm, the length of the wave face cell is 140cm and the width of each is 1m. On the upstream run in ramp to the obstacle, the jack cells are a combination of two thicknesses, being 10cm and 20cm. The width of the cells is varied to obtain a curved profile shape on the run in ramp rather than a linear one. Thus, the cells may be considered to be a series of steps where the thread widths progressively lengthen from top to bottom (upstream to downstream). Thus the width of the highest jack cell is 24.6, and the smaller jack cell on the same tier is 26.6cm, with the width of the cells on the next tier being 79.4cm and 34.3cm and on the bottom tier 153.5cm and 43.2cm. The overall length of the run-in ramp is approximately 3.5cm with the ramp and jack cell widths being 1m. The blocks making up the wall at the top are each 25cm thick, with the exception of the top or capping blocks which are 14cm thick.

It will be understood that where reference is made to the dimensions of an expandable section, element or cell, that the measurements are those generally in the expanded state rather than the collapsed state.

Claims

1. An obstacle for installing in a water flow, the obstacle comprising: a ramp section defining a water flow engaging surface; an expandable section comprising at least one expandable element having a reservoir and comprising a fluid inlet for receiving a fluid into the reservoir, wherein the shape or angle of the ramp section is set at least in part by the amount of fluid in the reservoir.

2. An obstacle according to claim 1, wherein the water engaging surface of the ramp is generally laminar.

3. An obstacle according to claim 1, wherein the water flow engaging surface is generally laminar.

4. An obstacle according to claim 1, wherein the obstacle is for forming a wave like water feature in a water flow.

5. An obstacle according to any one of claims 1 to 4, wherein there is a single expandable element connected to the ramp section which is expandable from a collapsed state to an inflated state, wherein the cross sectional shape of the expandable element is a wedge.

6. An obstacle according to any one of claims 1 to 5, wherein there are a plurality of expandable elements, wherein each of the elements is expandable from a collapsed state to an inflated state.

7. According to claim 5, wherein the aggregate cross sectional shape of the expandable sections in their expanded states is substantially that of a wedge or wedge like shape, for example a stepped shape.

8. An obstacle according to claim 5 or claim 6, wherein at least one of the expandable sections has a uniquely associated fluid inlet.

9. An obstacle according to any one of claims 5 to 7, wherein the plurality of expandable elements are arranged in a tiered structure.

10. An obstacle according to claim 8, wherein there is at least one expandable section in each tier of the structure.

11. An obstacle according to any one of claims 6 to 9, wherein at least one expandable element extends from the first side to the second side of the obstacle.

12. An obstacle according to any one of claims 6 to 10, wherein at least one of the expandable sections only extends partially across the obstacle.

13. An obstacle according to claim 11, wherein a plurality of the expandable elements are arranged in at least one group, wherein the expandable elements the group extend from the first side to the second side.

14. An obstacle according to any preceding claim, wherein at least one of the at least one expandable sections includes a pressure relief valve for releasing fluid from the reservoir.

15. An obstacle according to any preceding claim, further comprising at least one attachment point for anchoring the ramp.

16. An obstacle according to any preceding claim, wherein at least one outlet is provided to allow the expandable sections to be emptied.

17. An obstacle according to any preceding claim, wherein the outlet and inlet are the same.

18. An obstacle according to any preceding claim, wherein the ramp section is formed using at least one expandable element.

19. An obstacle according to any preceding claim, wherein the water flow engaging surface is formed using a flexible material.

20. The ramp section according to any one of claims 1 to 16, wherein the water flow engaging surface is formed using a rigid material.

21. An obstacle according to any preceding claim, wherein an edge of the obstacle is provided with a pocket extending from a first side to a second side of the obstacle and providing a space for a support bar or tether to be passed there through to assist in anchoring the obstacle.

22. An obstacle according to any preceding claim, wherein in a collapsed state the obstacle may be at least partially rolled up or folded for transport or storage.

23. An obstacle according to claim 21, wherein the obstacle comprises straps for retaining the obstacle rolled up.

24. An obstacle according to any preceding claim further comprising a pipe connected to the fluid inlet, to allow for the filling of the ramp with a fluid.

25. An obstacle according to claim 23, wherein the pipe is configured to be connected to a water supply remote from the ramp whilst in situ in a water flow.

26. An obstacle according to any preceding claim, wherein at least one of the at least one expandable elements is a drop stitch structure.

27. An obstacle according to any preceding claim, the obstacle further comprising a crash mat extending downstream from the obstacle.

28. An obstacle according to claim 26, wherein the crash mat is formed using one or more expandable elements.

29. An obstacle according to any preceding claim, wherein an upper surface of the obstacle is defined by two or more adjacent expandable elements and wherein a first one of the adjacent expandable elements comprises a flap which extends to cover the edge of a second expandable element.

30. An obstacle according to claim 28, wherein at least one fastener is provided for fastening the flap to the second expandable element.

31. An obstacle according to claim 29, wherein the fastener is a hook and loop fastener.

32. A method of installing a water flow obstacle in a water flow to create a wave like feature, the obstacle comprising a ramp section and at least one expandable element, the obstacle having a first state and a second state wherein in a first state the water flow is substantially unaffected and a second state in which the shape of the obstacle causes a wave like feature to form in the water flow, the method comprising the steps of: a) anchoring the obstacle to limit its movement in the water flow; and b) inflating the at least one expandable section with a fluid to cause the obstacle to change from its first state to its second state.

33. An obstacle for installing in a water flow, the obstacle comprising: an expandable section for installing below the surface of a flow of water the expandable section defining a reservoir and comprising a fluid inlet for receiving a fluid into the reservoir, wherein the obstacle has an upper surface and a lower surface wherein internal constraining features are provided within the expandable section to restrain the distance between the upper and lower surfaces when filled with fluid.

34. A wave feature installed in a water flow to create a wave, the wave feature comprising at least one jack cell and a wave face surface, wherein the jack cell is expandable from a collapsed state to an expandable state by filling with a fluid, wherein the jack cell is positioned below the face cell and causes a part of the face cell to rise up when the jack cell is filled from the collapsed state to the expanded state.

35. A method for creating a water flow obstacle substantially as herein before described with reference to and or as illustrated in the accompanying drawings.

36. A system for forming an obstacle substantially as herein before described with reference to and or as illustrated in the accompanying drawings.