WO1997048593A1 - Means for varying the shape of a boat hull - Google Patents

Means for varying the shape of a boat hull Download PDF

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Publication number
WO1997048593A1
WO1997048593A1 PCT/AU1997/000387 AU9700387W WO9748593A1 WO 1997048593 A1 WO1997048593 A1 WO 1997048593A1 AU 9700387 W AU9700387 W AU 9700387W WO 9748593 A1 WO9748593 A1 WO 9748593A1
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WO
WIPO (PCT)
Prior art keywords
hull
craft
panel
panels
inflated
Prior art date
Application number
PCT/AU1997/000387
Other languages
French (fr)
Inventor
Norman Leslie Matthew
Original Assignee
Norman Leslie Matthew
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Norman Leslie Matthew filed Critical Norman Leslie Matthew
Priority to AU30834/97A priority Critical patent/AU3083497A/en
Publication of WO1997048593A1 publication Critical patent/WO1997048593A1/en

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Classifications

    • BPERFORMING OPERATIONS; TRANSPORTING
    • B63SHIPS OR OTHER WATERBORNE VESSELS; RELATED EQUIPMENT
    • B63BSHIPS OR OTHER WATERBORNE VESSELS; EQUIPMENT FOR SHIPPING 
    • B63B7/00Collapsible, foldable, inflatable or like vessels
    • B63B7/06Collapsible, foldable, inflatable or like vessels having parts of non-rigid material
    • B63B7/08Inflatable
    • B63B7/082Inflatable having parts of rigid material
    • BPERFORMING OPERATIONS; TRANSPORTING
    • B63SHIPS OR OTHER WATERBORNE VESSELS; RELATED EQUIPMENT
    • B63BSHIPS OR OTHER WATERBORNE VESSELS; EQUIPMENT FOR SHIPPING 
    • B63B41/00Drop keels, e.g. centre boards or side boards ; Collapsible keels, or the like, e.g. telescopically; Longitudinally split hinged keels
    • BPERFORMING OPERATIONS; TRANSPORTING
    • B63SHIPS OR OTHER WATERBORNE VESSELS; RELATED EQUIPMENT
    • B63BSHIPS OR OTHER WATERBORNE VESSELS; EQUIPMENT FOR SHIPPING 
    • B63B1/00Hydrodynamic or hydrostatic features of hulls or of hydrofoils
    • B63B1/32Other means for varying the inherent hydrodynamic characteristics of hulls
    • B63B1/34Other means for varying the inherent hydrodynamic characteristics of hulls by reducing surface friction
    • BPERFORMING OPERATIONS; TRANSPORTING
    • B63SHIPS OR OTHER WATERBORNE VESSELS; RELATED EQUIPMENT
    • B63BSHIPS OR OTHER WATERBORNE VESSELS; EQUIPMENT FOR SHIPPING 
    • B63B59/00Hull protection specially adapted for vessels; Cleaning devices specially adapted for vessels
    • B63B59/02Fenders integral with waterborne vessels or specially adapted therefor, e.g. fenders forming part of the hull or incorporated in the hull; Rubbing-strakes
    • BPERFORMING OPERATIONS; TRANSPORTING
    • B63SHIPS OR OTHER WATERBORNE VESSELS; RELATED EQUIPMENT
    • B63BSHIPS OR OTHER WATERBORNE VESSELS; EQUIPMENT FOR SHIPPING 
    • B63B59/00Hull protection specially adapted for vessels; Cleaning devices specially adapted for vessels
    • B63B59/02Fenders integral with waterborne vessels or specially adapted therefor, e.g. fenders forming part of the hull or incorporated in the hull; Rubbing-strakes
    • B63B2059/025Fenders integral with waterborne vessels or specially adapted therefor, e.g. fenders forming part of the hull or incorporated in the hull; Rubbing-strakes pneumatic, e.g. inflatable
    • BPERFORMING OPERATIONS; TRANSPORTING
    • B63SHIPS OR OTHER WATERBORNE VESSELS; RELATED EQUIPMENT
    • B63BSHIPS OR OTHER WATERBORNE VESSELS; EQUIPMENT FOR SHIPPING 
    • B63B34/00Vessels specially adapted for water sports or leisure; Body-supporting devices specially adapted for water sports or leisure
    • YGENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02TCLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO TRANSPORTATION
    • Y02T70/00Maritime or waterways transport
    • Y02T70/10Measures concerning design or construction of watercraft hulls

Definitions

  • TITLE MEANS FOR VARYING THE SHAPE OF A BOAT HULL
  • This invention relates to improvements in water surface craft and hulls therefor. It is more particularly concerned with means whereby hull geometry or shape can be varied to alter the hydrodynamic and/or load-carrying properties of a craft and/or to facilitate propulsion of the craft when beached.
  • the invention is not confined to powered water craft, having valuable application to sailing craft and to sail-assisted motor vessels. It is applicable to craft of any size with any form of propulsion.
  • the shape or geometry of the hull of a particular water craft is designed to suit the intended use of the craft, whether it be pleasure cruising, commercial fishing, transport, military, policing, speed-racing, water-ski towing, etc.
  • Perhaps the most important feature of hull geometry for a fast open-water craft is the V-angle of the hull and how it changes from stem to stern, for many boats have a deep V-angle at the bow and a small angle at the stern.
  • a flat-bottomed boat ( ⁇ 5° V-angle) has a large load-carrying capacity with relative to wetted area, takes less power to plane but has a harsh ride, is difficult to control at speed and is sensitive to cross winds and waves.
  • a boat with a deep V-angle (more than 22°) has a lower load capacity and requires much more power to plane, but offers a more comfortable ride at speed and is generally more seaworthy.
  • hull design is compromise or trade-off between competing requirements. Even so, the fact is that no matter how well suited to its original design purpose, a water craft will encounter conditions for which its hull design is ill-suited. Most owners or operators of water craft have found themselves caught in sea, speed or load conditions for which their craft were not designed.
  • trim tabs, flaps or plates on the stern transoms of motor boats which can be adjusted to prevent the bow of the boat from lifting too much at speed.
  • the adjustment of these trim-tabs can be effected hydraulically from within the boat while it is use.
  • tabs do not change the hull shape or geometry of the boat and are capable of only limited effect, as the name implies.
  • moveable centreboards and lee-boards in sailing boats to change the hydrodynamic characteristics of the boat to suit beating or reaching tacks. Again, however, such boards do not change the lines of the hull, though they can have a major effect upon the performance of a sailing boat.
  • US patent No. 3,559,222 to Walker discloses a boat in which the lower portion of the hull is formed from hinged panels or pleated plastic sheeting which allow the hull to be changed from one with a flat bottom to one with a V-bottom by inflating a bladder situated below a water-tight floor of the craft.
  • the hinged or pleated hull is too fragile (whether flat or inflated) and complex to be practical.
  • Intermediate hull shapes are difficult to obtain and there is no ability to adjust the fore-and-aft transition from a V-form to a flat-form hull.
  • the operators of many different types of water craft have the occasional need to beach the craft to permit the transfer of goods or passengers where there are no port facilities, to undertake repair or maintenance of the hull, or simply to rest.
  • tourist and other craft which strike sand bars or mud flats have a need to move the craft off or along the bottom in a simple manner. This benefit is not offered by any of the above prior art references.
  • attachment means for varying the geometry of water craft, which means can be deployed while the craft is in motion or at rest to better suit the craft to speed, water, load or other use conditions.
  • a secondary and non-essential objective is to provide variable geometry means which will also facilitate beaching and de-beaching of the craft or, more generally, which will confer limited amphibious ability upon the craft.
  • Another, non-essential objective is to provide an attachment for fixing to the hull of an existing water craft to alter its hull shape or geometry.
  • the present invention is based upon the realisation that the shape of the hull of a water craft can be easily and effectively changed by the attachment or incorporation of flexible inflatable hull panels or sections. It is even possible in this way to change a hull shape from that designed for one purpose to that suited to a quite different purpose.
  • the panel or panels may be attached temporarily or incorporated in the design of the vessel itself.
  • further modification of hull shape can be effected if the panels are movably mounted or arranged on the hull; for example, so that a panel can be positioned anywhere between bow and stern as desired.
  • the panels or sections are movable with respect to the hull in this way, they can be used (i) to withdraw the panel(s) into or against the hull when they are not needed, or (ii), to enable the craft to propel itself onto, along and off a beach.
  • the flexible panels or sections are movable relative to the hull, they may conveniently be of tubular form and adapted so that they can be deployed longitudinally on the hull (using guide means, if desired) by withdrawing them from a storage location and/or from within the normal profile of the hull, or simply moving them along the exterior of the hull. Where they are not movable, the panels or sections can be permanently fixed to the hull, or located in recesses within the hull profile. Movement of the panels with respect to the hull may be effected by manual or powered drives from within the vessel. Many variations, arrangements and deployments of the panels envisaged by this invention are possible.
  • the panels may be inflated and deflated by the use of gas (most usually air) and/or liquid (most usually water) from an external source before sailing or by using pump means located within the craft.
  • gas most usually air
  • liquid most usually water
  • Figure 1 is a diagrammatic sectional side-elevation (taken on plane A-A of the plan view of Figure 2) of a small motorboat fitted with a moveable hull panel comprising the first example of the application of this invention.
  • Figure 2 is a diagrammatic plan view of the motorboat shown in Figure 1.
  • Figure 3 is a diagrammatic stern-elevation of the boat of Figures 1 and 2.
  • Figure 4 is a diagrammatic bow-elevation of the boat of Figures 1 and 2.
  • Figure 5 is a stern elevation of a craft fitted with two moveable attachment like that of the first example.
  • Figures 6A and 6B are diagrammatic transverse partial sections of a boat hull fitted with means for varying its shape, which means comprise the second example of the invention; Figure 6A showing said means uninflated and Figure 6B showing the said means inflated.
  • Figures 7A, 7B and 7C are diagrammatic perspectives of a pleasure craft comprising the third example of the invention in which the panel us coiled for stowage, the panel being shown fully stowed in Figure 7A, partially deployed in Figure 7B and fully deployed in Figure 7C.
  • Figures 8A and 8B are, respectively, a diagrammatic plan view from underneath of a speedboat hull fitted with a single inflated panel, and a series of sectional elevational outlines of the hull taken at various points.
  • Figures 9A, 9B and 9C are, respectively, a diagrammatic plan view from underneath of a speedboat hull fitted with two inflated panels, a series of sectional elevational outlines of the hull without the panels inflated, and a similar series of cross-sectional outlines of the hull taken with the panels inflated.
  • the first example of the invention (shown in Figures 1 to 4) is a welded-aluminium runabout 10 of between four and six metres in length with a hull bottom having a low V-angle (10-15°) suited to provide low lift-lift off (or planing) speeds in calm waters.
  • V-angle 10-15°
  • Such hulls can be readily planed with relatively low-power outboard motors but, having a small V-angle, lack lateral stability, tend to thump at speed even on small waves and are sensitive to side winds and moderate waves.
  • no propulsion or steering system is illustrated in the drawings.
  • the hull 11 of craft 10 is an open-topped shell with steeply sloping sides 12, a more gently sloping bow 14, a vertical stern transom 16 and low V-angle bottom 18.
  • Fixed along the outside of bottom 18 are a pair of parallel channels 20 into which a tubular inflatable panel 22 is slidingly engaged.
  • the length of panel 22 is a substantial proportion of the length of bottom 18, it can slide in channels 20 so that its stem end 24 aligns with the stern end 26 of channels 20 or so that its forward end 28 aligns with the forward end 30 of channels 22.
  • the panel is shown inflated and comprises the means whereby the shape or geometry of the centre of hull 11 has been effectively altered from (i) a low V-angle to a sharp V-angle (in excess of 22°), (ii) from a V-keel to a round keel shape and (iii) from a V-section which is the same along the whole hull 11 (except for bow 14) to a shorter bulbous section.
  • Panel 22 is moulded from tough but flexible fabric-reinforced rubber or plastic of the type well known in the inflatable dinghy art and its upper face is preferably covered with a low-friction material such as teflon (not shown).
  • a low-friction material such as teflon (not shown).
  • the sectional profile of the panel is determined largely by the choice of materials. It can be rigid and angular or bulbous (as in this case).
  • panel 22 tapers laterally and vertically into a hose or tube 32 (not drawn in section for clarity) through which panel 22 can be inflated and deflated. Tube 32 runs up bow 14 and enters hull 11 via a hole 34 at the top of the bow to a hose connection 36.
  • panel 22 may be slid along channels 20 and held in the desired position using a pair of bow cables 38 and a pair of stern cables 40 which are respectively wound onto a pair of bow winches 42 and a pair of stern winches 44.
  • panel 22 is positioned as desired before being fully inflated as inflation of the panel will generally hold it in position by friction in this embodiment.
  • Panel 22 can be inflated and deflated with air or water (or a mix of air and water) using a standard lever-operated diaphragm bilge-pump 50, the lever arm which is not shown being inserted into a central socket 52 and rocked to work the pump.
  • the outlet pipe 54 of pump 50 is connected to a multi-position outlet valve 56 which can be manipulated to connect pipe 54 to a waste outlet 58 that opens into side 12 of hull 11 or to connect pipe 54 to hose connection 36 via pipe 60.
  • the inlet pipe 62 of pump 50 is connected to a second multi-position valve 64 that can be manipulated to connect inlet pipe 62 to any one of the following pipes: air inlet 66, water inlet 68, bilge-pipe 70 or pipe 60 leading to hose connection 36.
  • bilge water can be pumped out by setting valve 64 to connect pipe 70 to inlet pipe 62 of pump 50 and setting valve 56 to connect outlet pipe 54 of pump 50 to waste pipe 58;
  • panel 22 can be inflated with air by connecting pump 50 with air inlet 66 and connecting outlet 54 to connection 36, or inflated with water by connecting the pump to water inlet pipe 68 instead.
  • valve 56 is set to connect pump 50 to waste pipe 58 and inlet valve 64 is set to connect pipe 60 with the pump.
  • Figure 5 illustrates the stern 80 of the same type of hull 82 as in the previous example fitted with attachment means comprising a pair of panels 84 (also of the same type as that example), each slidingly fitted into a pair of channel guides 86 as before.
  • attachment means comprising a pair of panels 84 (also of the same type as that example), each slidingly fitted into a pair of channel guides 86 as before.
  • the hydrodynamic shape of the hull is significantly altered.
  • a quick-fit air connection 88 is provided in the stern end of each panel so that it can be inflated before launching and after it has been located along its channel as desired. The friction between the hull and the panels is relied upon in this example to hold the panels in position in their channels.
  • hull 82 If hull 82 is considered to be resting on land (indicated by dashed line 90), it will be seen that its weight is entirely borne by panels 84 while they are inflated, but that hull 82 will rest on its bottom 92 if panels 84 are deflated.
  • means such as that described in the first example, are provided for (i) inflating and deflating panels 84 and (ii) moving them to and fro along channels 86 when both deflated and partially inflated, the hull can be moved along the ground. Indeed, the boat could be propelled an indefinite distance on a flat surface by:
  • FIGs 6A and 6B illustrate a different type of inflatable panel for use as attachment means for modifying the shape of the hulls of water craft.
  • the central portion of a medium-V hull bottom 93 is shown fitted with longitudinal angles 94 (rather than channels as before).
  • a semi-rigid longitudinal panel-board 95 having a central integral hinge 96 is used instead of a flexible inflatable bag-panel as in the previous examples, an inflatable bladder 97 being used behind panel 96 instead.
  • bladder 97 is deflated so that the original shape of hull bottom 93 is virtually unchanged but, in Figure 6B, bladder 97 is fully inflated to radically change the shape of the hull.
  • intermediate levels of inflation will result in intermediate V-angles.
  • FIGS 7A, 7B and 7C are diagrammatic transparent perspectives of a pleasure craft 100 fitted with a centrally deployed flexible tubular panel 102 which can be fully stowed by rolling it into a coil 104 (Figure 7A) in a storage chamber (not shown) in the stern 106 of craft 100.
  • Panel 102 is uncoiled and advanced along craft 100 toward the bow 107 by drawing in a pair of cables 108 that enter the hull through holes 110 some way aft of the bow 106. These cables may be housed in grooves formed within the hull surface.
  • Figure 7A shows the panel fully coiled at 102
  • Figure 7B shows panel 102 partially deployed
  • Figure 7C shows panel 102 fully deployed.
  • Inflation of panel 102 may be accomplished using a bow-end tube (not shown) as in the first example, or it may be effected by including a perforated non-collapsing tube (not illustrated) within the panel which runs the full length thereof, passes through the stern end of the panel and is connected to an inboard pump via a rotary joint (not shown) in the reel (not shown) on which panel 102 is coiled.
  • the panel may be inflated by the use of a pressure canister.
  • Figures 8A and 8B illustrate a deep-V speedboat hull 120 can be varied by the deployment of a single panel 122 along its the keel, the hull being viewed from underneath.
  • Figure 8B shows the transverse profile of hull 120 and panel 122 at various points there-along.
  • Figures 9A, 9B and 9C illustrate the way in which the load carrying capacity, buoyancy and lateral stability of a low lift-off planing-type speedboat hull 124 can be increased by the deployment of a pair of panels 126a and 126b, one panel being fitted to each side of the craft.
  • Figure 9A shows the hull from underneath
  • Figure 9B shows the transverse profile of the hull at various points therealong with the panels uninflated
  • Figure 9C shows the same sections with the panels inflated.
  • panels 122 and 126 need not be mounted for longitudinal movement but may be attached permanently or temporarily to their respective hulls.
  • the panels when inflated are shaped like mini-hulls with pointed tapering bow-ends and square, or at least more rapidly tapering, stern ends.
  • bow-panels may be employed which can be inflated to form a bulb below the waterline to reduce bow-wave energy when a craft is heavily loaded, heading into waves and deflated when the same craft is travelling empty or on calm seas.
  • Many other shapes of panels may be employed.
  • movable panels can be driven in many different ways besides the use of draw-cables.
  • a flexible tubular panel can be moved by the use of tractor wheels which grip its sides or a tractor drum which grips the entire panel and deflates it as it is drawn in. Movement of a panel relative to the hull into the operating position can be effected by the judicious use of inflation pressure and/or the drag of water when the craft is in motion. Though there is no need for a panel to be entirely storable inside the hull, this can be done in ways other than by coiling. The panel could be folded in concertina fashion or, more simply, just stored flat under the floor of the craft.
  • a centre-mounted panel can be guided simply by using the existing keel skeg, hull-V or round-form centre of a hull, without the need for any special guide channels or flanges.
  • Panels mounted off-centre can be guided by existing side chines or skegs, by slots or grooves especially formed in the hull to take guide strips or the like formed on the underside of the panel.
  • the panel may not need any lateral guides; one or two draw cables will often be sufficient to put the panels under the necessary tension to hold them in place when the craft is travelling at speed.
  • a deployed panel may be inflated in sections rather than all at once. This can be effected using a separate inflation tube for each section. Sectional inflation and deflation of a panel may be of material assistance in moving a craft when beached.
  • three or more overlapping movable panels are formed on a hull, they can be used to walk the craft onto the shore by sequential deflation, movement and inflation of the panels working in two sets.
  • the craft will be moved forwards by deflating one set of or more panels and moving them forwards along the hull while supporting the hull on the second set of one or more panels, moving the second set along the hull toward the stern (thereby moving the craft forward with respect to the land), inflating the first set to take the weight of the craft, deflating the second set and moving them forwards, and moving the first set rearwards (again moving the boat forwards); and so on.

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  • Chemical & Material Sciences (AREA)
  • Engineering & Computer Science (AREA)
  • Combustion & Propulsion (AREA)
  • Mechanical Engineering (AREA)
  • Ocean & Marine Engineering (AREA)
  • Physics & Mathematics (AREA)
  • Fluid Mechanics (AREA)
  • Toys (AREA)

Abstract

Means for modifying the hydrodynamic shape of water surface craft are disclosed which also enable the craft to travel short distances on a beach or other flat solid surfaces. A flexible panel (22) may be deployed below the waterline on the hull (11) of the craft and inflated to various degrees by pump means (50) to modify the transverse profile of the hull as desired. The longitudinal hull profile may be adjusted by moving the panel in the for and aft direction under the force of draw-cables (30, 40) or other means. If desired, the panel may be stored within the hull when not needed. When the craft is beached with the panel deflated, the panel (22) can be moved forward, inflated to take most of the weight of the craft and then moved rearwards relative to the hull so as to propel the craft forwards with respect to the ground.

Description

TITLE: MEANS FOR VARYING THE SHAPE OF A BOAT HULL
TECHNICAL FIELD
This invention relates to improvements in water surface craft and hulls therefor. It is more particularly concerned with means whereby hull geometry or shape can be varied to alter the hydrodynamic and/or load-carrying properties of a craft and/or to facilitate propulsion of the craft when beached.
The invention is not confined to powered water craft, having valuable application to sailing craft and to sail-assisted motor vessels. It is applicable to craft of any size with any form of propulsion.
BACKGROUND TO THE INVENTION
The shape or geometry of the hull of a particular water craft is designed to suit the intended use of the craft, whether it be pleasure cruising, commercial fishing, transport, military, policing, speed-racing, water-ski towing, etc. Perhaps the most important feature of hull geometry for a fast open-water craft is the V-angle of the hull and how it changes from stem to stern, for many boats have a deep V-angle at the bow and a small angle at the stern. A flat-bottomed boat (<5° V-angle) has a large load-carrying capacity with relative to wetted area, takes less power to plane but has a harsh ride, is difficult to control at speed and is sensitive to cross winds and waves. A boat with a deep V-angle (more than 22°) has a lower load capacity and requires much more power to plane, but offers a more comfortable ride at speed and is generally more seaworthy. In all vessels, hull design is compromise or trade-off between competing requirements. Even so, the fact is that no matter how well suited to its original design purpose, a water craft will encounter conditions for which its hull design is ill-suited. Most owners or operators of water craft have found themselves caught in sea, speed or load conditions for which their craft were not designed.
It is, of course, well known to use trim tabs, flaps or plates on the stern transoms of motor boats which can be adjusted to prevent the bow of the boat from lifting too much at speed. In some instances, the adjustment of these trim-tabs can be effected hydraulically from within the boat while it is use. However such tabs do not change the hull shape or geometry of the boat and are capable of only limited effect, as the name implies. Similarly, it is well known to use moveable centreboards and lee-boards in sailing boats to change the hydrodynamic characteristics of the boat to suit beating or reaching tacks. Again, however, such boards do not change the lines of the hull, though they can have a major effect upon the performance of a sailing boat.
In my prior US patent No. 4,351 ,262 I disclosed a catamaran-style hull for a power boat which can be effectively converted into a flat-bottomed monohull by lowering a central rigid subsidiary hull using a mechanical linkage employing hydropneumatic rams. As the subsidiary central hull could be lowered to a level below that of the side hulls, the rams could be used to raise the rest of the craft (when beached) off the sand or ground and to move it forwards or backwards, thus 'walking' the craft in the fore and aft direction. I also disclosed in that patent the use of an inflatable bladder between the subsidiary hull and the tunnel-roof joining the side hulls to assist the rams carry the weight of the craft when it was being walked, or when the craft was at sea with the subsidiary hull partially or fully lowered. Though the convertible craft disclosed in my US patent No. 4,351 ,262 enables the user to choose between a catamaran or monohull characteristic while the craft is being operated, it had limited application because it was not applicable to craft which were basically monohulls. Also, the range of hull variation was severely restricted. Furthermore, my earlier invention required a purpose-built craft as the auxiliary hull could not be readily attached to existing vessels.
US patent No. 3,559,222 to Walker discloses a boat in which the lower portion of the hull is formed from hinged panels or pleated plastic sheeting which allow the hull to be changed from one with a flat bottom to one with a V-bottom by inflating a bladder situated below a water-tight floor of the craft. However, the hinged or pleated hull is too fragile (whether flat or inflated) and complex to be practical. Intermediate hull shapes are difficult to obtain and there is no ability to adjust the fore-and-aft transition from a V-form to a flat-form hull. The operators of many different types of water craft have the occasional need to beach the craft to permit the transfer of goods or passengers where there are no port facilities, to undertake repair or maintenance of the hull, or simply to rest. On other occasions, tourist and other craft which strike sand bars or mud flats have a need to move the craft off or along the bottom in a simple manner. This benefit is not offered by any of the above prior art references.
In my recent copending international patent application PCT/AU96/00803 (unpublished at the date of this application), I disclose the use of movable tracks on the exterior of the hulls of water craft which can be used to draw the craft onto a beach and move them back into the water. However, the shape and hydrodynamic performance of the hull was little altered.
As taught by US patent No. 4,218,988 to Tucker, a water craft which floats on at least one centre and two outer pontoons can be moved on land by raising the centre pontoon and moving it forwards while supporting the weight of the craft by the outer pontoons, then lowering the centre pontoon to support the craft while raising the outer pontoons and moving them forwards. However, this type of craft is only suitable for carrying heavy loads at slow speed on water or land. Further since the pontoons are moved by geared mechanisms, the tare of the craft will be large with respect to its load carrying capacity. No means of altering the hull geometry was disclosed, other than by the partial raising of some pontoons from the water.
OBJECTIVES OF THE INVENTION
Accordingly, it is an objective of this invention to provide attachment means for varying the geometry of water craft, which means can be deployed while the craft is in motion or at rest to better suit the craft to speed, water, load or other use conditions.
A secondary and non-essential objective is to provide variable geometry means which will also facilitate beaching and de-beaching of the craft or, more generally, which will confer limited amphibious ability upon the craft. Another, non-essential objective is to provide an attachment for fixing to the hull of an existing water craft to alter its hull shape or geometry.
OUTLINE OF INVENTION The present invention is based upon the realisation that the shape of the hull of a water craft can be easily and effectively changed by the attachment or incorporation of flexible inflatable hull panels or sections. It is even possible in this way to change a hull shape from that designed for one purpose to that suited to a quite different purpose. The panel or panels may be attached temporarily or incorporated in the design of the vessel itself. Moreover, further modification of hull shape can be effected if the panels are movably mounted or arranged on the hull; for example, so that a panel can be positioned anywhere between bow and stern as desired. And, if the panels or sections are movable with respect to the hull in this way, they can be used (i) to withdraw the panel(s) into or against the hull when they are not needed, or (ii), to enable the craft to propel itself onto, along and off a beach.
Where the flexible panels or sections are movable relative to the hull, they may conveniently be of tubular form and adapted so that they can be deployed longitudinally on the hull (using guide means, if desired) by withdrawing them from a storage location and/or from within the normal profile of the hull, or simply moving them along the exterior of the hull. Where they are not movable, the panels or sections can be permanently fixed to the hull, or located in recesses within the hull profile. Movement of the panels with respect to the hull may be effected by manual or powered drives from within the vessel. Many variations, arrangements and deployments of the panels envisaged by this invention are possible.
The panels may be inflated and deflated by the use of gas (most usually air) and/or liquid (most usually water) from an external source before sailing or by using pump means located within the craft. As the volumes and pressure of fluid are low, manual pump means are quite feasible for small pleasure craft, but power driven pumps will be needed for larger craft. DESCRIPTION OF EXAMPLES
Having broadly portrayed the nature of the present invention, particular embodi¬ ments will now be described by way of example and illustration only. In the follow¬ ing description, reference will be made to the accompanying drawings in which many components are not drawn to scale for the sake of clarity. In the drawings:
Figure 1 is a diagrammatic sectional side-elevation (taken on plane A-A of the plan view of Figure 2) of a small motorboat fitted with a moveable hull panel comprising the first example of the application of this invention.
Figure 2 is a diagrammatic plan view of the motorboat shown in Figure 1.
Figure 3 is a diagrammatic stern-elevation of the boat of Figures 1 and 2.
Figure 4 is a diagrammatic bow-elevation of the boat of Figures 1 and 2.
Figure 5 is a stern elevation of a craft fitted with two moveable attachment like that of the first example.
Figures 6A and 6B are diagrammatic transverse partial sections of a boat hull fitted with means for varying its shape, which means comprise the second example of the invention; Figure 6A showing said means uninflated and Figure 6B showing the said means inflated.
Figures 7A, 7B and 7C are diagrammatic perspectives of a pleasure craft comprising the third example of the invention in which the panel us coiled for stowage, the panel being shown fully stowed in Figure 7A, partially deployed in Figure 7B and fully deployed in Figure 7C.
Figures 8A and 8B are, respectively, a diagrammatic plan view from underneath of a speedboat hull fitted with a single inflated panel, and a series of sectional elevational outlines of the hull taken at various points. Figures 9A, 9B and 9C are, respectively, a diagrammatic plan view from underneath of a speedboat hull fitted with two inflated panels, a series of sectional elevational outlines of the hull without the panels inflated, and a similar series of cross-sectional outlines of the hull taken with the panels inflated.
The first example of the invention (shown in Figures 1 to 4) is a welded-aluminium runabout 10 of between four and six metres in length with a hull bottom having a low V-angle (10-15°) suited to provide low lift-lift off (or planing) speeds in calm waters. Such hulls can be readily planed with relatively low-power outboard motors but, having a small V-angle, lack lateral stability, tend to thump at speed even on small waves and are sensitive to side winds and moderate waves. For simplicity, no propulsion or steering system is illustrated in the drawings.
The hull 11 of craft 10 is an open-topped shell with steeply sloping sides 12, a more gently sloping bow 14, a vertical stern transom 16 and low V-angle bottom 18. Fixed along the outside of bottom 18 are a pair of parallel channels 20 into which a tubular inflatable panel 22 is slidingly engaged. As will be seen from Figure 1 , although the length of panel 22 is a substantial proportion of the length of bottom 18, it can slide in channels 20 so that its stem end 24 aligns with the stern end 26 of channels 20 or so that its forward end 28 aligns with the forward end 30 of channels 22. In Figures 1 to 4, the panel is shown inflated and comprises the means whereby the shape or geometry of the centre of hull 11 has been effectively altered from (i) a low V-angle to a sharp V-angle (in excess of 22°), (ii) from a V-keel to a round keel shape and (iii) from a V-section which is the same along the whole hull 11 (except for bow 14) to a shorter bulbous section.
Panel 22 is moulded from tough but flexible fabric-reinforced rubber or plastic of the type well known in the inflatable dinghy art and its upper face is preferably covered with a low-friction material such as teflon (not shown). The sectional profile of the panel is determined largely by the choice of materials. It can be rigid and angular or bulbous (as in this case). Toward its bow-end 28, panel 22 tapers laterally and vertically into a hose or tube 32 (not drawn in section for clarity) through which panel 22 can be inflated and deflated. Tube 32 runs up bow 14 and enters hull 11 via a hole 34 at the top of the bow to a hose connection 36. In this embodiment, panel 22 may be slid along channels 20 and held in the desired position using a pair of bow cables 38 and a pair of stern cables 40 which are respectively wound onto a pair of bow winches 42 and a pair of stern winches 44. Preferably, panel 22 is positioned as desired before being fully inflated as inflation of the panel will generally hold it in position by friction in this embodiment.
Panel 22 can be inflated and deflated with air or water (or a mix of air and water) using a standard lever-operated diaphragm bilge-pump 50, the lever arm which is not shown being inserted into a central socket 52 and rocked to work the pump. The outlet pipe 54 of pump 50 is connected to a multi-position outlet valve 56 which can be manipulated to connect pipe 54 to a waste outlet 58 that opens into side 12 of hull 11 or to connect pipe 54 to hose connection 36 via pipe 60. The inlet pipe 62 of pump 50 is connected to a second multi-position valve 64 that can be manipulated to connect inlet pipe 62 to any one of the following pipes: air inlet 66, water inlet 68, bilge-pipe 70 or pipe 60 leading to hose connection 36. Thus, bilge water can be pumped out by setting valve 64 to connect pipe 70 to inlet pipe 62 of pump 50 and setting valve 56 to connect outlet pipe 54 of pump 50 to waste pipe 58; panel 22 can be inflated with air by connecting pump 50 with air inlet 66 and connecting outlet 54 to connection 36, or inflated with water by connecting the pump to water inlet pipe 68 instead. To deflate panel 22, valve 56 is set to connect pump 50 to waste pipe 58 and inlet valve 64 is set to connect pipe 60 with the pump.
Figure 5 illustrates the stern 80 of the same type of hull 82 as in the previous example fitted with attachment means comprising a pair of panels 84 (also of the same type as that example), each slidingly fitted into a pair of channel guides 86 as before. Again, the hydrodynamic shape of the hull is significantly altered. In this second example, a quick-fit air connection 88 is provided in the stern end of each panel so that it can be inflated before launching and after it has been located along its channel as desired. The friction between the hull and the panels is relied upon in this example to hold the panels in position in their channels. If hull 82 is considered to be resting on land (indicated by dashed line 90), it will be seen that its weight is entirely borne by panels 84 while they are inflated, but that hull 82 will rest on its bottom 92 if panels 84 are deflated. Thus, if means such as that described in the first example, are provided for (i) inflating and deflating panels 84 and (ii) moving them to and fro along channels 86 when both deflated and partially inflated, the hull can be moved along the ground. Indeed, the boat could be propelled an indefinite distance on a flat surface by:
1 deflating panels 84, letting hull 82 rest on the ground, and then drawing the panels as far forwards as possible in channels 86, 2 inflating panels 84 enough to take most if not all of the weight of the boat, and then drawing the panels aft as possible, so moving the boat forwards with respect to the land, and 3 repeating the procedure. Of course, the boat may be moved backwards in a similar way.
Figures 6A and 6B illustrate a different type of inflatable panel for use as attachment means for modifying the shape of the hulls of water craft. Here, the central portion of a medium-V hull bottom 93 is shown fitted with longitudinal angles 94 (rather than channels as before). In this case, however, a semi-rigid longitudinal panel-board 95 having a central integral hinge 96 is used instead of a flexible inflatable bag-panel as in the previous examples, an inflatable bladder 97 being used behind panel 96 instead. In Figure 6A bladder 97 is deflated so that the original shape of hull bottom 93 is virtually unchanged but, in Figure 6B, bladder 97 is fully inflated to radically change the shape of the hull. Obviously, intermediate levels of inflation will result in intermediate V-angles.
Referring now to Figures 7A, 7B and 7C which are diagrammatic transparent perspectives of a pleasure craft 100 fitted with a centrally deployed flexible tubular panel 102 which can be fully stowed by rolling it into a coil 104 (Figure 7A) in a storage chamber (not shown) in the stern 106 of craft 100. Panel 102 is uncoiled and advanced along craft 100 toward the bow 107 by drawing in a pair of cables 108 that enter the hull through holes 110 some way aft of the bow 106. These cables may be housed in grooves formed within the hull surface. Figure 7A shows the panel fully coiled at 102, Figure 7B shows panel 102 partially deployed, and Figure 7C shows panel 102 fully deployed. Inflation of panel 102 may be accomplished using a bow-end tube (not shown) as in the first example, or it may be effected by including a perforated non-collapsing tube (not illustrated) within the panel which runs the full length thereof, passes through the stern end of the panel and is connected to an inboard pump via a rotary joint (not shown) in the reel (not shown) on which panel 102 is coiled. Alternatively, the panel may be inflated by the use of a pressure canister.
Figures 8A and 8B illustrate a deep-V speedboat hull 120 can be varied by the deployment of a single panel 122 along its the keel, the hull being viewed from underneath. Figure 8B shows the transverse profile of hull 120 and panel 122 at various points there-along. Similarly, Figures 9A, 9B and 9C illustrate the way in which the load carrying capacity, buoyancy and lateral stability of a low lift-off planing-type speedboat hull 124 can be increased by the deployment of a pair of panels 126a and 126b, one panel being fitted to each side of the craft. Figure 9A shows the hull from underneath, while Figure 9B shows the transverse profile of the hull at various points therealong with the panels uninflated and Figure 9C shows the same sections with the panels inflated. In these examples, panels 122 and 126 need not be mounted for longitudinal movement but may be attached permanently or temporarily to their respective hulls.
Though the examples of the invention described above have met the objects and advantages set out at the beginning of this specification, those skilled in the art will understand that many variations and modifications can be made to the invention as disclosed without departing from its spirit or scope as defined by the following claims.
For example, there is advantage in ensuring that the panels (when inflated) are shaped like mini-hulls with pointed tapering bow-ends and square, or at least more rapidly tapering, stern ends. Alternatively, bow-panels may be employed which can be inflated to form a bulb below the waterline to reduce bow-wave energy when a craft is heavily loaded, heading into waves and deflated when the same craft is travelling empty or on calm seas. Many other shapes of panels may be employed.
It will also be appreciated that, where movable panels are used, they can be driven in many different ways besides the use of draw-cables. For instance, a flexible tubular panel can be moved by the use of tractor wheels which grip its sides or a tractor drum which grips the entire panel and deflates it as it is drawn in. Movement of a panel relative to the hull into the operating position can be effected by the judicious use of inflation pressure and/or the drag of water when the craft is in motion. Though there is no need for a panel to be entirely storable inside the hull, this can be done in ways other than by coiling. The panel could be folded in concertina fashion or, more simply, just stored flat under the floor of the craft.
Many alternative ways of guiding a moving panel may also be used. For example, a centre-mounted panel can be guided simply by using the existing keel skeg, hull-V or round-form centre of a hull, without the need for any special guide channels or flanges. Panels mounted off-centre can be guided by existing side chines or skegs, by slots or grooves especially formed in the hull to take guide strips or the like formed on the underside of the panel. Alternatively, the panel may not need any lateral guides; one or two draw cables will often be sufficient to put the panels under the necessary tension to hold them in place when the craft is travelling at speed.
A deployed panel may be inflated in sections rather than all at once. This can be effected using a separate inflation tube for each section. Sectional inflation and deflation of a panel may be of material assistance in moving a craft when beached.
Where three or more overlapping movable panels are formed on a hull, they can be used to walk the craft onto the shore by sequential deflation, movement and inflation of the panels working in two sets. Thus, the craft will be moved forwards by deflating one set of or more panels and moving them forwards along the hull while supporting the hull on the second set of one or more panels, moving the second set along the hull toward the stern (thereby moving the craft forward with respect to the land), inflating the first set to take the weight of the craft, deflating the second set and moving them forwards, and moving the first set rearwards (again moving the boat forwards); and so on.
Finally, though the illustrated examples have been confined to small craft, there is no necessary limit to the size of the water craft on which the panels of the invention may be used. The stability of large craft can be improved using a central panel inflated with water and/or air. Ships with round-bottomed hulls can be stabilised using panels mounted on the outside edges of the bottom of the hulls. The attachment means of this invention are particularly suited for deployment on the chines of craft with chined hulls as the angle of the chine serves to positively locate the panels or other means in place.
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Claims

1 A water craft having a buoyant and rigid elongate hull comprising a bow and a stern joined by an external water-engaging surface shaped to facilitate forward propulsion of the craft through the water, the craft being characterised in that at least one flexible and inflatable panel is attached to said hull surface such that the hydrodynamic shape of the hull is changed by the inflation or deflation of said panel.
2 Attachment means for modifying the hydrodynamic properties of the hull of a water surface craft comprising at least one flexible and inflatable panel adapted for attachment to the wetted surface of the hull, such that the hydrodynamic shape of the hull is changed by the inflation or deflation of said panel.
2 A craft or attachment means according to claim 1 or claim 2 including guide means extending in the fore and aft direction on or for attachment to said hull surface, said guide means being adapted to locate said panel for movement relative to the hull in the fore-and-aft direction, such that said movement of the panel changes the hydrodynamic properties of the hull.
A craft or attachment according to claim 2 characterised in that the length of the panel exposed to the water increases or reduces as the panel is moved relative to said guide means, thereby changing the hydrodynamic properties of the hull.
4 A craft or attachment means according to claim 2 or 3 wherein the panel is elongate and tubular, one end of said tubular panel is free for deployment in said guide means on the outside of the hull, the other end of said tubular panel is located in a storage position on or within the hull.
5 A craft or attachment means according to claim 4 including reel or the like whereon the tubular panel is coiled for deployment in said guide means. 48593 PC17AU97/00387
13 A craft or attachment means according to any one of claims 2 to 5 including drive means attached to either or both ends of the panel and adapted to position the panel within the guide means in the fore and aft direction.
A craft or attachment means according to claims 6 wherein said drive means includes a tension member secured to one or both ends of the panel, and winch means attached the tension member for applying tension to the tension member to effect positioning of the panel in the fore and aft direction.
A craft or attachment means according to any one of claims 2 to 7 wherein a pipe extends from one end of the panel and into the hull whereby the panel may be inflated or deflated from within the hull.
A craft or attachment means according to any one of claims 2 to 8 wherein the panel is extended from the bow toward the stern of the hull and is retracted from the stern toward the bow of the hull, or vice versa.
A craft according to any one of claims 2 to 9 wherein: one or more of said panels are provided in a central location in the bottom surface of the hull so that, when the hull is resting on a flat solid surface, the craft can be raised from that surface by extending and inflating said panel or panels, and the bottom of the hull is shaped so that, when said one or more panels are fully deflated, the hull can rest on a solid flat surface so that little if any of the weight of the craft is carried by said one or more panels, the arrangement being such that the craft can be walked on a flat solid surface by extending said one or more panels to a first position relative to the hull and inflating them to take the weight of the craft, moving said one or more panels relative to the craft to a second position so that the craft is moved relative to the surface, deflating said one or more panels, returning said one or more panels to the first position and repeating the process.
A craft according to any one of claim 10 wherein: • two sets of said panels are provided in the bottom surface of the hull, each set comprising at least one panel, each of said sets of panels is adapted, when extended and inflated, to support the full weight of the craft from a solid flat surface, • each set of panels is positioned in the hull so that when its panel or panels are fully extended and inflated it is capable of supporting the rest of the craft from a flat solid surface, the arrangement being such that the craft can be walked on a flat solid surface by extending one set of panels to a first position relative to the hull and inflating the panel or panels of said one set to take the weight of the craft, moving the panels of said one set relative to the craft so that the craft is moved relative to the flat surface, inflating and extending the second set of panels to take the weight of the craft, deflating and retracting the panels of said one set to said first position, moving the panels of the second set relative to the hull to move the hull relative to the flat surface, and repeating the process.
A craft according to any preceding claim wherein at least one of said panels extends along, or is capable of being extended along the keel or a chine of the hull.
A craft according to any preceding claim wherein one of said panels is arranged on each side of each keel of the hull.
A craft according to any preceding claim wherein at least one of said panels is elongate and is of a V-section when inflated.
A craft according to claim 14 wherein each of said V-section panel or panels tapers toward its bow end and terminates abruptly at its stern end to thereby form a step in the hull surface when the panel is inflated. A craft according to any preceding claim wherein the hull has a hard chine and the guide means comprise returns formed at each chine for retaining a panel there-between.
A craft according to any one of claims 1 to 15 wherein the guide means comprise cables strung under the hull along which the panel can be extended or retracted.
PCT/AU1997/000387 1996-06-14 1997-06-16 Means for varying the shape of a boat hull WO1997048593A1 (en)

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AUPO0428A AUPO042896A0 (en) 1996-06-14 1996-06-14 Further improved craft
AUPO0428 1996-06-14

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GB2362358A (en) * 2000-05-20 2001-11-21 Colin Hilton A wing or hull structure shaped by evacuation of air from within
GB2441987A (en) * 2006-09-23 2008-03-26 Joshua Harle Varying the underwater shape of a marine vessel
US10106225B1 (en) 2014-08-29 2018-10-23 Bombardier Recreational Products Inc. Hull for a watercraft
RU2702286C1 (en) * 2019-02-04 2019-10-07 Михаил Федорович Харченко Ship hull
CN111703262A (en) * 2020-06-02 2020-09-25 蚌埠市神舟机械有限公司 Pushing type water skis device of amphibious vehicle head
CN112937756A (en) * 2021-03-14 2021-06-11 哈尔滨工程大学 Air cushion support deformation boat body

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US3559222A (en) * 1968-10-28 1971-02-02 Nolte Albert C Jr Boat with adjustable bottom
FR2251470A1 (en) * 1973-11-20 1975-06-13 Bueri Sauveur Rough weather safety device for small boat - has inflatable bags in recesses along the boat sides
US4351262A (en) * 1980-02-15 1982-09-28 Matthews Leslie N Boat hull
FR2517620A1 (en) * 1981-12-07 1983-06-10 Hennebutte Georges Unsinkable float for marine vessel - has inflatable float attached to hull exterior sides with flexible straps for covering
AU3200784A (en) * 1983-08-16 1985-02-21 Heilbronn, K.N. Improvements in water craft
GB2162131A (en) * 1984-07-04 1986-01-29 Lifeguard Equip Ltd Improvements in or relating to buoyancy tubes
GB2168932A (en) * 1984-12-28 1986-07-02 Lifeguard Equip Ltd Inflatable boats
EP0568501A1 (en) * 1992-04-27 1993-11-03 Giuseppe Floris Inflatable hull protecting device for boats

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Publication number Priority date Publication date Assignee Title
US3559222A (en) * 1968-10-28 1971-02-02 Nolte Albert C Jr Boat with adjustable bottom
FR2251470A1 (en) * 1973-11-20 1975-06-13 Bueri Sauveur Rough weather safety device for small boat - has inflatable bags in recesses along the boat sides
US4351262A (en) * 1980-02-15 1982-09-28 Matthews Leslie N Boat hull
FR2517620A1 (en) * 1981-12-07 1983-06-10 Hennebutte Georges Unsinkable float for marine vessel - has inflatable float attached to hull exterior sides with flexible straps for covering
AU3200784A (en) * 1983-08-16 1985-02-21 Heilbronn, K.N. Improvements in water craft
GB2162131A (en) * 1984-07-04 1986-01-29 Lifeguard Equip Ltd Improvements in or relating to buoyancy tubes
GB2168932A (en) * 1984-12-28 1986-07-02 Lifeguard Equip Ltd Inflatable boats
EP0568501A1 (en) * 1992-04-27 1993-11-03 Giuseppe Floris Inflatable hull protecting device for boats

Cited By (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB2362358A (en) * 2000-05-20 2001-11-21 Colin Hilton A wing or hull structure shaped by evacuation of air from within
GB2441987A (en) * 2006-09-23 2008-03-26 Joshua Harle Varying the underwater shape of a marine vessel
US10106225B1 (en) 2014-08-29 2018-10-23 Bombardier Recreational Products Inc. Hull for a watercraft
RU2702286C1 (en) * 2019-02-04 2019-10-07 Михаил Федорович Харченко Ship hull
CN111703262A (en) * 2020-06-02 2020-09-25 蚌埠市神舟机械有限公司 Pushing type water skis device of amphibious vehicle head
CN112937756A (en) * 2021-03-14 2021-06-11 哈尔滨工程大学 Air cushion support deformation boat body
CN112937756B (en) * 2021-03-14 2022-06-21 哈尔滨工程大学 Air cushion support deformation boat body

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