WO2021240446A1

WO2021240446A1 - Amphibious watercraft

Info

Publication number: WO2021240446A1
Application number: PCT/IB2021/054667
Authority: WO
Inventors: Rex Edward MICHAU
Original assignee: Michau Rex Edward
Priority date: 2020-05-29
Filing date: 2021-05-28
Publication date: 2021-12-02

Abstract

A self-propelled amphibious watercraft capable of travel on a body of water and of being grounded to travel on ground, the amphibious watercraft comprising: a hull able to float on the body of water and including a bow region, stern region and keel extending, on the centreline of the hull; a drive track able to be powered by a motor inside the hull and extending along at least part of the keel and presented in a manner to be able to make contact, when the hull is grounded, with the ground and cause the hull be propelled over the ground when the drive track is powered; and, lateral stabilisers dependent from the hull each la presenting at least one load bearer able to make contact with and move with the hull over the ground when the hull is grounded to keep the hull on even keel on the ground.

Description

AMPHIBIOUS WATERCRAFT

FIELD OF INVENTION

The present invention relates to an amphibious watercraft. In particular, although not solely, the present invention relates to an amphibious watercraft utilising a mono-hull capable of propulsion on water and having a centralised drive track operational along the keel line to enable its propulsion on land.

BACKGROUND

To date amphibious watercraft have used wheel or track systems connected to or built into the hull of the watercraft in various configurations. For example, US 7,314,395 of Sealegs International Ltd describes a system with multiple wheels that extend downwards at the bow and stern port and starboard sides to lift and carry the hull on land and that are capable of being retracted for when the water going watercraft is traveling on water.

The amphibious watercraft of US 7,314,395 has its amphibious systems mostly located outside the hull. This and the system's additional running gear can get in the way of boating activities such as fishing, launching and recovery. The Sealegs tripod arranged wheels can also be unstable on rough, undulated or stepped terrain.

WO 2013/160605 is an example of an amphibious watercraft that utilises tracks deployable from each side of a hull to allow the vehicle to travel on land. The tracks arrangement of WO 2013/160605, longitudinally extending on the port and starboard sides, can have improved stability. However fore/aft stability may still not be adequate. Furthermore WO 2013/160605 utilises two continuous and driven track systems and this can be costly. Existing amphibious watercraft are hence often limited to the terrain that they can navigate due to arrangements that bring the centre of gravity up to unstable heights above the ground. Indeed, it is common knowledge that many locations have no suitable or difficult launching and retrieving areas for trailer boats. Even a smooth and even beach can be a difficult place for launching and retrieving a boat. Passenger cars, used for launching and retrieving trailer boats, are usually only suitable at sheltered boat ramps. At shallow incline beaches, tractors are often used as they can travel further into the water due to higher ground clearance. Tractors usually also have better ground traction for use on soft sand or muddy conditions. Tractors are also used to haul heavy boats. But in some locations even tractors struggle to trailer launch and retrieve boats. Challenging terrain such as deep wet and/or dry sand, gravel, pea shingle, rocks and water conditions creating variable wave height all make launching and retrieving a boat difficult. Many non-trailered amphibious watercraft are also known to struggle in such challenging terrain. Many amphibious watercraft are more appropriately used when the water is calm and the terrain is smooth and compact. Existing amphibious watercraft have a slow operating system for launching and landing making them difficult if not impossible to launch or land on a beach when substantial waves are running. When for example landing some known amphibious watercraft , the speed of the vehicle (once being propelled on land) can be far slower than the wave speed. This can cause broaching or swamping of the watercraft by the waves as they wash past and/or into the slow moving watercraft. Such slow moving amphibious watercraft are very vulnerable to waves when getting launched or retrieved as waves may tip the watercraft and could be considered dangerous if the wave height increases.

The Sealegs amphibious vehicle described in US 7,314,395 utilise a hydraulic motor direct driving the wheels and as such these hydraulic motors end up being submerged below the waterline when entering or leaving the water. This increases the need for periodic maintenance and associated costs and may also increases chance of failure. The wheels have motors at the wheel hubs and when submerged in salt water, elastomeric or similar sealing systems can fail. Salt water and sand environments combined with rotating shafts and seals, vastly reduces the life and dependability of many existing systems.

Accordingly it is an object of the present invention to provide an amphibious watercraft that addresses at least one of the above mentioned disadvantages and/or that will at least provide the public with a useful choice.

BRIEF DESCRIPTION OF THE INVENTION

In a first aspect, the invention may be said to broadly consist of a self- propelled amphibious watercraft capable of travel on a body of water and of being grounded to travel on ground, the amphibious watercraft comprising: i. a hull able to float on the body of water and including a bow region and stern region and a keel extending, on the centreline of the hull, between (and preferably to) the bow and stern region, ii. a drive track able to be powered (eg to be driven for movement) by a motor inside the hull and extending along at least part of the keel and presented from the hull in a manner to be able to make contact, when the hull is grounded, with the ground and cause the hull be propelled over the ground when the drive track is powered by the motor, iii. lateral stabilisers dependent from the hull on each of the port side and starboard side of the keel, each lateral stabiliser presenting at least one load bearer able to make contact with and move with the hull over the ground when the hull is grounded preferably to keep the hull on even keel on the ground.

Preferably, each the lateral stabiliser can move its respective loaded bearer(s) between a deployed condition where load bearers are presented to make contact and move over the ground and a retracted condition where the lateral stabilisers are elevated more compared to their deployed condition. Preferably, each the lateral stabiliser can move its respective loaded bearer(s) between a deployed condition where load bearers are below the waterline of the hull and presented to make contact and move over the ground and a retracted condition where the lateral stabilisers are elevated above the waterline of the hull.

Preferably the load bearers, when in their deployed condition, and the drive track are co-planar..

Preferably when in the deployed condition, the lateral stabilisers are able to position the load bearers at at least one vertical height position relative the hull..

Preferably when in the deployed condition, the lateral stabilisers are able to position the load bearers at at least two different vertical height positions relative the hull..

Preferably when in the deployed condition, the lateral stabilisers are able to position the load bearers between at least two vertical height positions relative the hull..

Preferably the load bearers are each actively controlled for positioning in deployed height when in their deployed condition, to allow for un-even ground that the hull may travel over..

Preferably the load bearers are each actively controlled for positioning between the two vertical height positions..

Preferably the load bearers are each automatically controlled for positioning between the two vertical height positions based on feedback from a level sensor able to sense the roll level of the hull .. Preferably the load bearers are each automatically controlled for positioning between the two vertical height positions based on feedback from a level sensor able to sense the roll level of the hull to allow for un-even ground that the hull may travel over and help maintain the hull at a zero roll angle..

Preferably, the lateral stabilisers each comprise of a carriage presenting the at least one load bearer and secured directly or indirectly to the hull in a manner able to move relative to the hull to allow the load bearers to move between their deployed condition and retracted condition.

Preferably the carriage is secured to the hull in a manner pivotal relative to the hull..

Preferably the carriage is secured to the hull in a manner translational relative to the hull..

Preferably the carriage is able to be actuated for movement relative the hull..

Preferably the watercraft has one hull (e.g. it is a monohull) with only hull one centreline..

Preferably the hull carries a water-based propulsion system (e.g. an outboard motor or inboard motor driving a propeller or impeller)..

Preferably the watercraft is of a monohull configuration..

Preferably the keel, at any given lateral cross section through the hull, is the lowest part of the hull..

Preferably the keel is V or U shaped at least through its mid-ships region.. Preferably the keel is flat bottomed at least through its mid-ships region..

Preferably the hull is V or U shaped at least through its mid-ships region..

Preferably at any given lateral cross section through the hull that incorporated the drive track, the drive track is the lowest part of the watercraft..

Preferably, each the lateral stabiliser comprises an actuator provided to cause the carriage to move relative the hull.

Preferably, the at least one load bearer comprises of at least one wheel able to make rolling contact with the ground when in the deployed condition.

Preferably, the at least one wheel is a powered wheel able to be driven by a motor.

Preferably, the at least one wheel is an idle wheel.

Preferably, rolling contact resistance of at least one of the at least one wheel of at least one lateral stabiliser can be varied in order to steer the watercraft as it moves on ground.

Preferably, at least one of the at least one wheel of at least one lateral stabiliser is able to be locked or braked against rolling contact in order to steer the watercraft as it moves on ground.

Preferably at least one of the at least one wheel of at least one lateral stabiliser is able to be locked or braked powered forward or reversed against rolling contact in order to steer the watercraft as it moves on ground.. Preferably alternatively the at least one load bearer comprises of at least one track able to make rolling contact with the ground when in the deployed condition..

Preferably the at least one track is a powered track able to be driven by a motor..

Preferably the at least one track is an idle track or may be operable in powered manner powered by the motor and idle manner decoupled or isolated from motor power..

Preferably at least one of the at least one track of at least one lateral stabiliser is able to be locked or braked against rolling contact in order to steer the watercraft as it moves on ground..

Preferably, a coupling is connected to the hull allowing the watercraft to be coupled to a land vehicle to be able to be towed by the land vehicle.

Preferably, the coupling is provided at the end of a draw bar that is connected to the hull.

Preferably the load bearers comprise of road wheels to allow the amphibious watercraft to be towed on a road by a road vehicle.

Preferably the draw bar is able to move relative to the hull between a stowed condition and a use condition..

Preferable the draw bar is connected to the hull at the bow region..

Preferably the draw bar is connected to the hull at the bow region in a manner to pivot relative to the hull between a stowed condition and use condition.. Preferably, when the load bearers are in their deployed condition the watercraft is able to be towed by a vehicle (such as a car or tractor).

Preferably the wheels or tracks of the lateral stabilisers are able to be braked and in a manner so that when the watercraft is being towed by a vehicle, the braking of the wheels of the lateral stabilisers is controlled by the vehicle..

Preferably the wheels or tracks of the lateral stabilisers are able to be powered and/or braked by an on-watercraft controller, able to be controlled by a person driving the watercraft..

Preferably the wheels or tracks of the lateral stabilisers are able to change between:

(i) a first mode powered and/or braked by an on-watercraft controller, able to be controlled by a person driving the water craft, and

(ii) a second mode isolated from the first mode whereby the wheels of the lateral stabilisers are not able to be powered and/or braked by the on- watercraft controller.

Preferably the wheels or tracks of the lateral stabilisers are able change between:

(ii) a second mode isolated from the first mode whereby the wheels of the lateral stabilisers are able to be braked and in a manner so that when the watercraft is being towed by a vehicle, the braking of the wheels of the lateral stabilisers is controlled by the vehicle..

Preferably when the watercraft is being towed by a vehicle, the wheels or tracks of the lateral stabilisers are un-able to be braked by the on- watercraft controller.. Preferably when being towed by a vehicle, braking of at least one of the at least one wheel of each lateral stabilisers is able to occur actively upon a brake signal being generated by the vehicle or passively by an inertia braking system..

Preferably the draw bar comprises an inertia braking system able to hydraulically cause a braking of at least one wheel of each of the lateral stabilisers..

Preferably at least one of the at least one wheels or tracks of at least one and preferably each lateral stabiliser is able to be braked mechanically, hydraulically, pneumatically or electrically and this is preferably controlled from onboard the hull by an operator of the watercraft..

Preferably at least one of the at least one wheels or tracks of at least one and preferably each lateral stabiliser is able to be braked by application of friction by a friction roller controlled mechanically, hydraulically, pneumatically or electrically and this is preferably controlled from onboard the hull by an operator of the watercraft..

Preferably the load bearers comprise of one of load bearing (a) wheels (b) skids (c) tracks and (d) load skates..

Preferably, the drive track comprises of a plurality of wheels extending as an array along the keel and rotationally mounted by the hull each about an axis lateral to the fore/aft direction of the hull at least some of which are powered by a motor inside the hull.

In a further aspect of the invention, there may be provided an amphibious arrangement of a drive track and lateral stabilisers for a watercraft (the arrangement may for example be retrofittable) that comprises a hull able to float on the body of water and including a bow region and stern region and a keel extending, on the centreline of the hull, between the bow and stern region, the arrangement comprising i. said drive track able to be powered by a motor inside the hull and to extend along at least part of the keel and be presented from the hull in a manner to be able to make contact, when the hull is grounded, with the ground and cause the hull be propelled over the ground when the drive track is powered, ii. said lateral stabilisers to secure to the hull and be dependent from the hull on each of the port side and starboard side of the keel, each lateral stabiliser presenting at least one load bearer able to make contact with and move with the hull over the ground when the hull is grounded to keep the hull on even keel on the ground.

In a further aspect the present invention may be said to be a method of operating an amphibious watercraft as herein defined during a beach landing of the watercraft traveling on a body of water that has waves breaking on the beach, the method comprising prior to grounding the hull, travelling the watercraft towards the beach, causing the lateral stabilisers to assume their deployed condition and either prior to or upon grounding of the hull powering the drive track to cause it to move relative to the hull in a direction to drive the watercraft out of the body of water over the ground.

Preferably the lateral stabilisers are moved from their retracted condition to their deployed condition prior to grounding the hull.

Preferably the watercraft is caused to move towards the beach when on the body of water, at a speed approximately the same or faster than the speed of the breaking waves.

Preferably the drive track is powered to move at a speed relative to the hull so that the watercraft is moved out of the body of water over the ground at approximately the same or faster speed as the speed of the breaking waves.

Preferably the watercraft is able to be towed from the beach and onto a carriageway by a tow vehicle..

Preferably the lateral stabilisers remain deployed when the watercraft is being towed..

Preferably the drive track is depowered when the watercraft is being towed..

One of more statements above relating to any one aspect may equally apply to another aspect(s).

Other aspects of the invention may become apparent from the following description which is given by way of example only and with reference to the accompanying drawings.

The entire disclosures of all applications, patents and publications, cited above and below, if any, are hereby incorporated by reference.

In this specification where reference has been made to patent specifications, other external documents, or other sources of information, this is generally for the purpose of providing a context for discussing the features of the invention. Unless specifically stated otherwise, reference to such external documents is not to be construed as an admission that such documents, or such sources of information, in any jurisdiction, are prior art, or form part of the common general knowledge in the art.

As used herein the term "and/or" means "and" or "or", or both. As used herein "(s)" following a noun means the plural and/or singular forms of the noun.

For purposes of the description hereinafter, the terms "upper",

"lower", "right", "left", "vertical", "horizontal", "top", "bottom", "lateral", "longitudinal" and derivatives thereof shall relate to the invention as it is oriented in the drawing figures. However, it is to be understood that the invention may assume various alternative variations, except where expressly specified to the contrary.

Further, for purposes of the description hereinafter, nautical directional terms such as "fore", "aft", "bow", "stern", "starboard", "port" and the like, may be used interchangeably with the terms listed above and are generally provided in a non-limiting explanatory capacity and shall be construed or interpreted as they would be a person skilled in the art.

The term "drive track" used herein preferably comprises the use of an endless traction belt preferably with treads and running over a series of support wheels. However it is envisaged that the drive track may utilise a plurality of in-line wheels preferably configured as an array forming a notional track due to the proximity and/or interconnection of such wheels by a drive arrangement. The drive track may also come in the form of an auger extending longitudinally along the keel line. The drive track may also come in the form of two wheels spaced apart and located proximate the bow and stern of the hull respectively.

It is also to be understood that any specific examples illustrated in the attached drawings and described in the following description are simply exemplary embodiments of the invention. Hence, specific dimensions and other physical characteristics related to the embodiments disclosed herein are not to be considered as limiting. It is acknowledged that the term "comprise" may, under varying jurisdictions, be attributed with either an exclusive or an inclusive meaning. For the purpose of this specification, and unless otherwise noted, the term 'comprise' shall have an inclusive meaning, allowing for inclusion of not only the listed components or elements, but also other non-specified components or elements. The terms 'comprises' or 'comprised' or 'comprising' have a similar meaning when used in relation to the system or to one or more steps in a method or process.

As used hereinbefore and hereinafter, "(s)" following a noun means the plural and/or singular forms of the noun.

When used in the claims and unless stated otherwise, the word 'for' is to be interpreted to mean only 'suitable for', and not for example, specifically 'adapted' or 'configured' for the purpose that is stated.

Unless specifically stated otherwise, in this specification, use of the word 'substantially' with a term, to define a characterizing feature(s), gets all the benefit (i.e. benefit of any broadening) afforded by the use of the word 'substantially', and also includes within its scope the feature(s) being that term exactly, (without broadening). For example, if a feature is described/defined in the present specification as being 'substantially orthogonal' then that includes, within its scope, the feature being 'close' to orthogonal (in so far the word 'substantially' is deemed to broaden the term 'orthogonal'), and also includes within its scope the feature being 'exactly' orthogonal.

This invention may also be the broadly to consist in the parts, elements and features referred to or indicated in the specification of the application, individually or collectively, and any or all combinations of any two or more of the parts, elements or features, and where specific integers are mentioned herein which have known equivalents in the art to which this invention relates, such known equivalents are deemed to be incorporated herein as if individually set forth.

BRIEF DESCRIPTION OF THE DRAWINGS

Various embodiments of the present invention will now be described, by way of example, and with reference to the figures, in which:

Figure 1 shows a perspective view of an embodiment amphibious watercraft.

Figure 2A shows a perspective view of a lateral stabiliser of an embodiment amphibious watercraft in the retracted condition.

Figure 3A shows a perspective view of a lateral stabiliser of an embodiment amphibious watercraft in the deployed condition.

Figure 3A shows a schematic view of a skid steering arrangement of an embodiment amphibious watercraft.

Figure 3B shows a schematic side view of a braking arrangement of an embodiment amphibious watercraft.

Figure 4A shows a side view of a towing arrangement of the watercraft of figure 1 in its stowed condition.

Figure 4B shows a side view of a towing arrangement of the watercraft of figure 1 in its stowed condition with the towing hitch folded.

Figure 4C shows a side view of a towing arrangement of the watercraft of figure 1 in its deployed condition.

Figure 4D shows a perspective view of a towing arrangement of the watercraft of figure 1 in its deployed condition.

Figure 5A shows a schematic side view of a drive track arrangement of an embodiment amphibious watercraft.

Figure 5B shows a schematic top view of the drive track arrangement of figure 5A. Figure 6A shows a perspective view of an example drive track arrangement of an embodiment amphibious watercraft having an in-line motor arrangement.

Figure 6B shows a perspective view of an example drive track arrangement of an embodiment amphibious watercraft having a dual motor arrangement.

Figure 6C shows a schematic side view of a traction belt of a drive track arrangement of an embodiment amphibious watercraft.

Figure 6D shows a perspective view of a traction belt a drive track arrangement of an embodiment amphibious watercraft.

Figure 6E shows a close-up perspective view of the traction belt figure 6D.

Figure 7A shows a schematic side view of a lateral stabiliser of an embodiment amphibious watercraft.

Figure 7B shows a schematic cross sectional view of an embodiment amphibious watercraft having the lateral stabilisers of figure 7A.

Figure 8A shows a schematic side view of an embodiment amphibious watercraft having a drive track arrangement with two wheels.

Figure 8B shows a schematic side view of an embodiment amphibious watercraft having a drive track arrangement with an array of wheels.

Figure 8C shows a schematic front view of an embodiment amphibious watercraft having its load bearers deployed to different heights.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS.

Exemplary embodiments of the invention will now be described with reference to figures 1-7B showing a self-propelled amphibious watercraft 100 and aspects thereof. The watercraft 100 described herein is capable of travel on a body of water and of being grounded to travel on ground, the ground being naturally formed such as a beach of sand and the like, or gravel, or combinations thereof, or artificially formed, such as a gravel or concrete or other-wise composed man-made structure such a boat-ramp, which may for instance, be covered with sand, gravel or seaweed as would be envisaged at the interface between a body of water and ground.

An embodiment of the amphibious watercraft 100 is shown in figure 1 comprising a hull 1 able to float on the body of water and including a bow region 3 and stern region 5 with port and starboard sides and a keel 7 extending, on the centreline of the hull 1, between the bow 3 and stern region 5. The hull is preferably a mono-hull.

The amphibious watercraft 100 as shown in figure 1 may have an elevated cabin section that may accommodate passengers of the watercraft, for instance, as typically provided for smaller recreational fishing vessels. However, it will be appreciated that in some embodiments, the watercraft 100 may include a wide range of cabin or non-cabin watercraft designs or configurations, and is not limited to the forms disclosed herein in the figures and corresponding description. Those skilled in the art will appreciate that the following description may apply to an amphibious watercraft 100 having a wide range of cabin or non-cabin designs between the bow and stern regions 3, 5. The watercraft 100 may also be provided with an outboard motor, or integrated propellers (not shown in the figures or herein described) as known in the art, to provide propulsion during naval travel.

The amphibious watercraft 100 further comprises a drive track 9 able to be powered by at least one and preferably one motor 11 inside the hull 1. The drive track is configured to extend along at least part of the keel 7 and presented from the hull 1 in a manner to be able to make contact, when the hull 1 is grounded, with the ground and cause the hull 1 to be propelled over the ground when the drive track 9 is powered, as described in further detail below with reference to figures 5A-6E. The watercraft is able to be grounded on a beach for example and utilising the drive track, can crawl up the beach and out of the water. The amphibious watercraft 100 also comprises lateral stabilisers 13 dependent from the hull 2 on each of the port side and starboard side of the keel 7, each lateral stabiliser presenting at least one load bearer 15. Each at least one load bearer is able to make contact with and allow movement with the hull 1 over the ground when the hull is grounded. The lateral stabilisers are able to help keep the hull 1 on even keel when on the ground. The lateral stabilisers are effectively roll stabilisers to help keep the hull at preferably a zero roll angle. They are lateral in the sense that they are positioned on the port and starboard sides relative the centreline of the hull. They are preferably located on at the port and starboard sides of the hull. The lateral stabilisers may also herein be referred to as port and starboard stabilisers.

In some configurations, each of the lateral stabiliser 13 can move its respective loaded bearer(s) 15 between a deployed condition 13A, as shown in figure 1, where the load bearers 15 are presented to make contact and move over the ground, and a retracted condition 15B, as shown in figures 2A and 2B, where the lateral stabilisers 15 are elevated more compared to their deployed condition 15A.

In the deployed condition 15A, the lateral stabilisers 13 and bearer(s) 15 thereof may provide a ride-height and track width typical of conventional road-going vehicles such as passenger cars, trucks, or more preferably, commercial load-bearing vehicles such as road trailers, boat trailers and the like. In this way, the amphibious watercraft 100 provides road-going capability that may meet typical standards of road-going vehicles in a given state or territory.

In some forms, each lateral stabiliser 13 can move its respective load bearer(s) 15 between a deployed condition 15A where load bearers 15 are below the waterline IX of the hull 1 and presented to make contact and move over the ground and a retracted condition 15B where the lateral stabilisers 15 are elevated above the waterline IX of the hull 1. Thus, it will be appreciated that when in the retracted condition 15B, the lateral stabilisers 13 and bearers 15 thereof may not extend into a body of water when the hull 1 travels therethrough, so as to reduce fluid drag on the vessel 100.

Further, the lateral stabilisers 13 may each comprise of a carriage presenting the at least one load bearer 15 and secured directly or indirectly to the hull 1 in a manner able to move relative to the hull 1 to allow the load bearers 15 to move between their deployed condition 15A and retracted condition 15B.

This is shown in figures 2A and 2B, wherein the lateral stabiliser arrangement is shown in the deployed condition 15A in figure 2B and in the retracted condition 15B in figure 2A. As shown, the load bearer(s) 15 may comprise road wheels having road tires, for instance, configured to make rolling contact with the ground when in the deployed condition 15A. They wheels may have rubber road tires, off-roading road tires, or any other suitable configuration wheel and tire combination as desired for movement of the watercraft 100 over grounded terrain. Throughout the figures, two load bearer(s) 15 are shown for each lateral stabiliser 13, however, it will be appreciated that the lateral stabilisers 13 may instead comprise only one, or any other plurality of load bearer(s), such as three or four or more.

Those skilled in the art will envisage appropriate arrangements of load bearer(s) depending on the size, weight and application of the watercraft 100. For instance, a smaller, recreational fishing embodiment of the watercraft 100 intended for deployment to and from a sand beach may only require two load bearer(s) on each lateral stabiliser 13with road-going wheel/tire combinations typical of road-going trailers, for instance.

However, a heavier and larger commercial fishing embodiment of the amphibious watercraft 100 may instead require four load bearer(s) on each lateral stabiliser 13 that may have more heavy-duty off-roading wheel/tire combinations more suitable for rougher terrain deployment, such as a rocky or gravel beach, for example.

The load bearer(s) are shown in figures 2A and 2B suspended from a carriage 17. The carriage 17 comprising an upper carriage member 17A, an intermediate carriage member 17B, and a lower carriage member 17C. Wherein the upper carriage member 17A is fixed to the hull 1, preferably contained therein. The load bearer(s) 15 are more specifically suspended from the lower carriage member 17C using shock-absorbing springs 19 and swing arms 21. The springs 19 and swing arms 21 may provide ride compliance during grounded travel of the amphibious watercraft 100. The springs 19 may also be constant tension springs that assist in counterbalancing the watercraft's 100 weight upon the load bearer(s) 15, so as to improve traction and ride-quality over rough terrain.

The lower carriage member 17C is operatively connected to the intermediate carriage member 17B by sliding arrangement on intermediate runners 23 extending downwardly from the intermediate carriage member 17B. The intermediate carriage member 17B is correspondingly operatively connected to the upper carriage member 17A by sliding arrangement on main runners 25 extending downwardly from the upper carriage member 17A.

An actuator 27 mounted to the upper carriage member 17A extends to the lower carriage member 17C. The actuator 27 may thus displace upwardly and downwardly to effect movement of the lower and intermediate carriage members 17B, 17C along their respective main and intermediate runners 23, 25. The actuator 27 thus allows the carriage 17 to move relative to the hull 1 between the deployed and retracted conditions 15A, 15B.

In some embodiments, the wheels 15 may be powered and able to be driven by a motor, or may be non-powered or idle wheels. In either case, the rolling contact resistance of the wheels 15 or load bearer(s) of at least one of at least one lateral stabiliser 13 can be varied in order to steer the watercraft 100 as it moves on ground. This may be achieved, for example, by effecting a change in the drive power provided by a drive motor of the wheels 15, if provided.

Alternatively, or additionally, braking or rolling lock may be effected onto the load bearer(s) or wheels 15 to the same effect. Thus, in some configurations, at least one of the at least one wheel 15 of at least one lateral stabiliser 13 is able to be locked or braked against rolling contact in order to steer the watercraft 100 as it moves on ground.

Examples of such a braking or locking skid steering arrangement are shown in figures 3A and 3B. Figure 3B shows a single wheel or load bearer 15 suspended from a lower carriage member 17C using a shock-absorbing spring and swing arm 19, 21 as previously described. Coupled to the swing arm 21 is a linear actuator 29A that may displace a spring or clamp loaded friction roller 29B towards the tire of the wheel 15 to effect braking force. Other brake arrangements may also be employed such as drum or disk brakes known in the art.

Figure 3A shows a schematic skid steering arrangement 200 that may be employed to control and effect the skid steering. Towing hitch 301, described in further detail below, may be coupled to a hydraulic actuator 203 thus connected to a hydraulic fluid tank 205. The actuator and tank 203, 205 provide pressurised hydraulic fluid through lines 206 that carry the pressurised hydraulic fluid to either lateral stabiliser 13 of the watercraft 100.

Each lateral stabiliser 13 may be thus provided a combination solenoid valve 207A, 207B, slave cylinder 209A, 209B, brake arrangement 211A, 211B (such as that shown in figure 3B, or a drum or disk brake arrangement known in the art) having corresponding linear actuator 209A, 209B (which may comprise linear actuator 29A as shown in figure 3B), and slave cylinder 213A, 213B and corresponding actuator 215A, 215B. The actuators 215A, 215B may be electrical, hydraulic or mechanical, and may compress slaves cylinder 213A, 213B to thus effect movement of pressurised hydraulic fluid to the brake arrangement 211A, 211B and corresponding linear actuator 209A, 209B of the lateral stabilisers 13.

To effect skid steering control, a solenoid valve 207A of one of the lateral stabilisers 13 may be closed such that pressurised hydraulic fluid is prevented from travelling to corresponding brake arrangement 211A and corresponding linear actuator 209A. Thus, when hydraulic actuator 203 sends pressurised hydraulic fluid along lines 206, the fluid is forced to travel through the open solenoid valve 207B, and effect braking through brake arrangement 211B and corresponding linear actuator 209B, causing load bearer(s) 15 of the associated lateral stabiliser 13 to brake or lock as desired and thus steer the watercraft 100 as desired.

The provision of skid steering control may in some embodiments benefit from having the ground-contacting portion of the drive track 9 arranged such that the length of said ground-contacting portion forward of the braked load bearer 15 (and thus pivot point) is equal to the length of said ground-contacting portion rearward of the braked load bearer 15. This thus reduces the turning circle of the watercraft 100 during said skid steering. It may reduce the turning circle to have a radius equal to that of the distance from the braked load bearer 15 to the bow 3 of the watercraft 100.

In non-skid steering mode, both solenoid valves 207A, 207B remain open so as to effect equal braking of the load bearer(s) 15 of both lateral stabiliser 13 and thus brake the watercraft 100 during grounded travel. It will be appreciated that the solenoid valves 207A, 207B may be configured to only partially seal, so as to provide finite or adjustable skid steering control rather than binary skid steering control. A towing arrangement 300 is shown in figures 4A-4D. It may comprise of a coupling comprising a towing hitch 301, connected to the hull 1 via hinged arrangement with a drawbar pin 303, which itself couples to a pair of locking arms 305 and a drawbar 307. The drawbar 307 hinges upon drawbar pin 309 that connects the drawbar 307 to the hull cavity 1A. The pair of locking arms 305 also hinged to the hull cavity 1A via locking arm hinges 311. The hinged configuration allows the towing arrangement 300 to collapse and be stowed into the hull cavity 1A as shown in figures 4A and 4B, where figure 4B shows the towing hitch 301 rotated so as to be contained between the elongate members of the drawbar when in the collapsed configuration.

The coupling comprising the towing hitch 301 allows the watercraft 100 to be coupled to a land vehicle to be able to be towed by the land vehicle, the coupling being provided at the end of the drawbar 307 connected to the hull 1 via the drawbar pin 303.

Accordingly, when the watercraft 100 is grounded and load bearer(s)

15 are deployed, the towing arrangement 300 allows the watercraft 100 to be towed by a vehicle such as a passenger car, tractor, truck or the like. The load bearers may be positioned at a height relative to the hull when in their deployed condition to ensure the drive track is clear of ground contact when the watercraft is being towed in this manner.

The drive track 9 will now be described in further detail with reference to figures 5A-6E. Figure 5A shows a side schematic view of the watercraft 100, and figure 5B shows a top schematic view thereof. As can be seen, the drive track 9 comprises an endless traction belt 51 extending in the fore/aft direction of the hull 1 at the keel 7 of the hull 1.

In particular, the drive track 9 comprises an endless traction belt 51 spanning between a stern end roller 55 at or near the stern region 5 of the hull 1 and a forward end roller 53 nearer the bow region 3 of the hull 1. The traction belt 51 may be able to rotate about the stern and forward end rollers 53, 55, such that it presents a first length 51A thereof below the keel 7 of the hull 1 and a second length 51B substantially parallel the first length 51A and above the first length 51A. The traction belt may along its first length 51A at each lateral side therefor substantially flush with the hull 1, as shown.

As such, the traction belt 51 and the hull 1 at where the traction belt 51 is presented from the hull 1 are substantially flush with each other. Thus, the traction belt 51 may be, or comprise a shape and configuration to be substantially flush with the hull 1. Further, the traction belt 51 may be, or comprise a shape and configuration to have an interface with the hull 1 to thereat seal against the hull 1 and reduce the egress of water from the body of water beyond the interface. This may be provided by rubber sealing about a periphery of the interface, for instance, and as described in further detail below with reference to figure 7B.

The endless traction belt 51 may be able to be powered by the motor 11 to be driven to rotate about the stern and forward end rollers 53, 55. The traction belt 51 may be powered by the motor 11 to be driven for movement relative the hull 1 via a transmission 57 between the motor 11 and the traction belt 51.

This is shown in more detail in figures 6A and 6B. Figure 6A shows an in-line motor 11A coupled to transmission 57 comprising a gearbox that may transfer power from the motor 11A via a gear or chain or belt transmission through to the forward end roller 55. Alternatively, a geared motor (or motors) 11B may be mounted coaxially to the forward end roller 55 to directly transfer power thereto. Figure 6B shows the motor arrangement of figures 5A and 5B in more detail, with a pair of drive motors 11C coupled to a gear or chain or belt transmission 57 transferring power to the forward end roller 55.

Figure 5A also shows a plurality of sprockets 61 arranged between the first and second lengths 51A, 51B of the traction belt 51. These may act to help drive the belt 51 during rotation thereof. Figure 6C shows a side- schematic view of the endless traction belt 51 in further detail. Wherein on an inner face of the belt 51 are disposed dog members 63 provided to interface with the sprockets 61 to help drive the belt 51. Also shown are longitudinal guides 63 provided to guide the belt 51. The treads 67 are bolted or otherwise fastened to the belt 51 using fasteners 69 that pass through the belt 51 to connect to the dog members 63 on the inner face thereof, as shown in figure 6D.

Figure 6E shows a close up view of the treads 67. As can be seen, the treads 67 may each comprise transversely oriented side rollers 71 on lateral sides of the tread 67 presenting rolling surfaces to assist in reducing rolling resistance in the longitudinal direction. Further provided may be a longitudinally oriented central roller 73 protruding from an apex of the treads 67, presenting rolling surfaces to assist in reducing rolling resistance in the transverse direction.

The treads 67 may be concave on both the leading edge 75 and trailing edge 77 thereof so that both fluid and solid materials may pass along the tread during grounded or naval travel of the watercraft 100 with minimal resistance or drag. Further, the lateral side areas 79 of the traction belt 51 may be tapered or angled so as to match the keel 7 draft/taper or angle of the hull 1 and thus minimise drag and also assist in providing sealing at the interface between the drive track 9 and hull 1.

In some embodiments, the drive track 9 extends along the keel 7 a distance at least 40%, 50%, 60% or 70% of the hull length. Further, as shown in figure 5A, the drive track 9 may comprise an auxiliary actuator 61C coupled with an intermediate sprocket 61 B of the plurality of sprockets 61, that is configured to displace the intermediate sprocket 61B to effect a change in the contour, path or profile of the first length 51A of the traction belt 51 so that it extends or protrudes downwardly out from the keel 7 of the hull 1. This may be provided to adjust contact area of the traction belt 51 with the ground and thus adjust traction provided by the drive track 9 as so desired when turning or travelling over ground.

Whilst in a preferred form the drive track comprises of one traction belt preferably powered by one motor, it is envisaged that two or more in line traction belts may be used that may each individually powered or powered together. There may be a fore and aft more traction belt provisioned to the hull of the watercraft.

Figure 7B shows a front cross-sectional view of an internal housing 80 of the hull 1 for the drive track 9 and associated traction belt, motors, sprockets and the like described above. As can be seen, and as hereinbefore described, the traction belt 51 may be so configured so as to be flush with the keel 7 of the hull 1 of the watercraft 100 to thus have an interface with the hull 1 to thereat seal against the hull 1 and reduce the egress of water from the body of water beyond the interface. This may be provided by rubber sealing 81 about a periphery of the interface, for instance.

In some instances, such as when the watercraft 100 is travelling through water, the water may egress past the interface or rubber sealing 81. In such case, the motors, transmission, sprockets and the like described above of the drive track 9 may be positioned vertically upwards within the internal housing 80 of the hull 1, to reduce the likelihood of any egressed water from flooding the components. The amphibious watercraft 100 described herein may be so configured such that any powered drivers or drive line components such as motors, gearboxes and actuators are arranged above the waterline IX of the hull 1, as shown in figure figures 5A and 7B, so as to help reduce or eliminate their exposure to water. The traction belt is preferably located at and in a wet-box of the hull along the keel. Any water passing beyond the preferred sealed interface may enter the wet-box but not beyond and into the hull in a manner to case the hull to sink. The transmission may pass through the wet box housing in a sealed manner. The internal housing 80 may be or comprise the wet-box. In some embodiments, the drive track 9 may comprise, instead of a traction belt 51 and associated treads 67, a plurality of wheels extending as an array along the keel 7 and rotationally mounted by the hull 1 each about an axis lateral to the fore/aft direction of the hull and wherein at least one and preferably at least two the wheels are powered by the motor 11 inside the hull 1. The wheels each at their lower region project out of the hull 1 under the keel 7 of the hull 1, and may in some forms, be able to rotate idle. This is shown in figures 8A and 8B, in which figure 8A shows the drive track 9 comprising two wheels 110 mounted on two axles 112 along the line of the keel 7. The axles 112 may themselves have direct-mounted geared motors. Figure 8B shows an array of wheels 120 mounted to axles 112 that may also be individually motorised or may instead comprise sprockets arranged as described above in relation to the traction belt 51 and similarly driven by fore, aft or both fore and aft motors via a transmission arrangement such as those described above.

An alternative to the lateral stabilisers 13 described hereinbefore is shown in figure 7A, wherein a plate housing 91 having an arcuate profile is mounted about a pivot 93 within the hull 1. The pivot 3 may be actuated to rotate the plate housing 91 from a retracted condition within the hull 1 to a deployed condition so as to present an array of load bearer(s) 95 or wheels 95 mounted about the arcuate profile thereof. Thanks to the curved arrangement of wheels 95, when in the deployed condition on very uneven ground, such as a rock-bed, at least one of the wheels 95 is in contact with the ground. The wheels 95 may be rigidly mounted to the housing 91 or otherwise suspended, however, it will be appreciated that such an embodiments may typically be provided for very rough grounded travel, and thus, not require ride compliance desired of a road-going vehicle and therefore not require suspension.

The amphibious watercraft 100 herein described may thus be able to climb steep terrain and navigate challenging rugged shorelines such a sand, rocky and shingle shores. The width of the track 9 and/or the profile of the track 9, , preferably matching that of the keel 7 of the hull 1, may assist in the grounded travel such as over asphalt or concrete, soil and loose land surfaces like sand and pea shingle, and may also reduce drag when moving through water.

The amphibious watercraft 100 herein described is able to offer enhanced motion stability when in the water by having the lateral stabilisers 13 at least partially deployed when the amphibious watercraft is stationary or is moving through the water. This may create resistance to roll motion of the hull 1 thereby increasing stability. Generally, the watercraft 100 may be so configured such that the various features and components described herein are arranged as vertically low as possible to further provide a low centre of gravity and improved stability and manoeuvrability both in water and on ground.

In some embodiments, the watercraft 100 may comprise internal storage compartments that allow room for ancillary equipment such as capstans and fish boxes, for example. Further, these compartments may be so balanced with the hull 1 and other features of the watercraft 100 herein described to allow for even weight distribution as desired for naval use. The drive track 9 provided along the keel 7 provides an internal channel as part of the wet box that may increase the rigidity of the hull 1.

In some embodiments, the load bearer(s) 15 and/or drive track 9 may be configured to free-wheel or idle such that the hull 1 may beach at speed and help maintain momentum of the watercraft 100 to reach dry land. This can be beneficial, for instance, when landing onto a beach that has substantial waves rolling thereon. Before landing the lateral stabilisers 13 may be deployed so that their respective load bearers 15 are at a height preferably in line with the keel 7. This enables the watercraft 100 to be in contact with land along the drive track 9 and at the lateral stabilisers 13 to provide stability to the watercraft 100 as it transitions out of the water. In some embodiments, when in the deployed condition, the lateral stabilisers 13 (whether comprising load bearer(s) 15 shown in figures 2A-2B or comprising an array of arcuate arranged wheels 95 as shown in figures 7A-7B) are able to position the load bearers at at least one, if not two different, vertical height position relative the hull. The load bearers may each further be actively controlled for positioning in deployed height when in their deployed condition, to allow for un-even ground that the hull may travel over. This is shown schematically in figure 8C, in which the load bearers 15, 95 may be actively or automatically controlled for positioning between the two vertical height positions 150A, 150B, based on feedback from a level sensor 160 able to sense the roll level of the hull 1 to allow for un-even ground that the hull 1 may travel over and help maintain the hull 1 at a zero roll angle.

It will be appreciated that aspects of the amphibious watercraft 100 described herein may be applied equally to an amphibious arrangement of a drive track and lateral stabilisers for a watercraft, such that an existing watercraft or vessel may be modified or retrofitted with the features described herein to provide a modified vessel having similar features, functions and the associated benefits. The watercraft thus comprising a hull able to float on the body of water and including a bow region and stern region and a keel extending, on the centreline of the hull, between the bow and stern region. The arrangement comprising said drive track able to be powered by a motor inside the hull and to extend along at least part of the keel and be presented from the hull in a manner to be able to make contact, when the hull is grounded, with the ground and cause the hull be propelled over the ground when the drive track is powered, and said lateral stabilisers to secure to the hull and be dependent from the hull on each of the port side and starboard side of the keel, each lateral stabiliser presenting at least one load bearer able to make contact with and move with the hull over the ground when the hull is grounded to keep the hull on even keel on the ground. Those skilled in the art will also envisage a method of operating the amphibious watercraft 100 described herein during a beach landing of the watercraft 100 traveling on a body of water that has waves breaking on the beach, the method comprising prior to grounding the hull 1, travelling the watercraft 100 towards the beach, causing the lateral stabilisers 13 to assume their deployed condition and either prior to or upon grounding of the hull 1 powering the drive track 9 to cause it to move relative to the hull 1 in a direction to drive the watercraft 100 out of the body of water over the ground. Further, the lateral stabilisers 13 may be moved from their retracted condition 15B to their deployed condition 15A prior to grounding the hull 1. Further, the watercraft 100 may be caused to move towards the beach when on the body of water, at a speed approximately the same or faster than the speed of the breaking waves, with the drive track 9 powered to move at a speed relative to the hull 1 so that the watercraft 100 is moved out of the body of water over the ground at approximately the same or faster speed as the speed of the breaking waves.

Claims

Claims:

1. A self-propelled amphibious watercraft capable of travel on a body of water and of being grounded to travel on ground, the amphibious watercraft comprising: i. a hull able to float on the body of water and including a bow region and stern region and a keel extending, on the centreline of the hull, between the bow and stern region, ii. a drive track able to be powered by a motor inside the hull and extending along at least part of the keel and presented from the hull in a manner to be able to make contact, when the hull is grounded, with the ground and cause the hull be propelled over the ground when the drive track is powered, iii. lateral stabilisers dependent from the hull on each of the port side and starboard side of the keel, each lateral stabiliser presenting at least one load bearer able to make contact with and move with the hull over the ground when the hull is grounded to keep the hull on even keel on the ground.

2. The amphibious watercraft as claimed in claim 1 wherein each of the lateral stabiliser can move its respective loaded bearer(s) between a deployed condition where load bearers are presented to make contact and move over the ground and a retracted condition where the lateral stabilisers are elevated more compared to their deployed condition.

3. The amphibious watercraft as claimed in claim 1 or 2 wherein each of the lateral stabiliser can move its respective loaded bearer(s) between a deployed condition where load bearers are below the waterline of the hull and presented to make contact and move over the ground and a retracted condition where the lateral stabilisers are elevated above the waterline of the hull.

4. The amphibious watercraft as claimed in anyone of claims 2 to 3 wherein the lateral stabilisers each comprise of a carriage presenting a said at least one load bearer and secured directly or indirectly to the hull in a manner able to move relative to the hull to allow the load bearers to move between their deployed condition and retracted condition.

5. The amphibious watercraft as claimed in claim 4 wherein each of the lateral stabiliser comprises an actuator provided to cause the carriage to move relative the hull.

6. The amphibious watercraft as claimed in anyone of claims 1 to 5 wherein the at least one load bearer comprises of at least one wheel able to make rolling contact with the ground when in the deployed condition.

7. The amphibious watercraft as claimed in claim 6 wherein the at least one wheel is a powered wheel able to be driven by a motor.

8. The amphibious watercraft as claimed in claim 6 wherein the at least one wheel is an idle wheel.

9. The amphibious watercraft as claimed in anyone of claims 6 to 8 wherein rolling contact resistance of at least one of the at least one wheel of at least one lateral stabiliser can be varied in order to steer the watercraft as it moves on ground.

10. The amphibious watercraft as claimed in anyone of claims 6 to 9 wherein at least one of the at least one wheel of at least one lateral stabiliser is able to be locked or braked against rolling contact in order to steer the watercraft as it moves on ground.

11. The amphibious watercraft as claimed in anyone of claims 1 to 10 wherein a coupling is connected to the hull allowing the watercraft to be coupled to a land vehicle to be able to be towed by the land vehicle.

12. The amphibious watercraft as claimed in claim 11 wherein the coupling is provided at the end of a draw bar that is connected to the hull.

13. The amphibious watercraft as claimed in anyone of claims 1 to 12 wherein when the load bearers are in their deployed condition the watercraft is able to be towed by a vehicle.

14. The amphibious watercraft as claimed in anyone of claims 1 to 13 wherein the drive track comprises of a plurality of wheels extending as an array along the keel and rotationally mounted by the hull each about an axis lateral to the fore/aft direction of the hull at least some of which are powered by a motor inside the hull d

15. An amphibious arrangement of a drive track and lateral stabilisers for a watercraft that comprises a hull able to float on the body of water and including a bow region and stern region and a keel extending, on the centreline of the hull, between the bow and stern region, the arrangement comprising i. said drive track able to be powered by a motor inside the hull and to extend along at least part of the keel and be presented from the hull in a manner to be able to make contact, when the hull is grounded, with the ground and cause the hull be propelled over the ground when the drive track is powered, and ii. said lateral stabilisers to secure to the hull and be dependent from the hull on each of the port side and starboard side of the keel, each lateral stabiliser presenting at least one load bearer able to make contact with and move with the hull over the ground when the hull is grounded to keep the hull on even keel on the ground.

16. A method of operating an amphibious watercraft as claimed in anyone of claims 1 to 14 during a beach landing of the watercraft traveling on a body of water that has waves breaking on the beach, the method comprising prior to grounding the hull, travelling the watercraft towards the beach, causing the lateral stabilisers to assume their deployed condition and either prior to or upon grounding of the hull powering the drive track to cause it to move relative to the hull in a direction to drive the watercraft out of the body of water over the ground.

17. A method as claimed in claim 16 wherein the lateral stabilisers are moved from their retracted condition to their deployed condition prior to grounding the hull.

18. A method as claimed in claim 16 or 17 wherein the watercraft is caused to move towards the beach when on the body of water, at a speed approximately the same or faster than the speed of the breaking waves.

19. A method as claimed in anyone of claims 16 to 18 wherein the drive track is powered to move at a speed relative to the hull so that the watercraft is moved out of the body of water over the ground at approximately the same or faster speed as the speed of the breaking waves.