FIELD OF INVENTION

The invention relates to a lightweight boat comprising wheels and a wheel deployment and retraction system. The boat may be a towable boat, towable by a vehicle, when on land.

BACKGROUND

One way to launch a boat into water and retrieve it after use is to use a trailer which carries the boat. The user reverses the vehicle and trailer down a launching ramp or beach and launches or retrieves the boat from there. Loading and unloading a boat to and from a trailer at a launching ramp can be cumbersome and time consuming. The need for a trailer also increases cost for a boat user.

Contemporary systems have been developed where a boat has its own powered wheels which allow it to drive out of the water without the need for a trailer. However these systems are complex, prone to failure and can compromise the boat's hydrodynamics. Smaller boats can be manually moved in or out of water.

SUMMARY OF INVENTION

It is an object of the invention to provide a lightweight towable boat which aims to ameliorate at least some of the problems mentioned above or to provide a useful choice for the public. In a first aspect the invention broadly comprises a boat comprising wheels and a wheel deployment and retraction system comprising :

left and right wheel assemblies, and wheel wells in an underside of the hull to receive the wheel assemblies when the boat is on water, a mechanical linkage between the left and right wheel assemblies, across a floor of the boat at the floor or beneath the floor, and through the hull to the wheel assemblies, a lever connected to the mechanical linkage which is manually operable to a first position to deploy the wheels below the hull when the boat is on land and a second position to retract the wheels into the wheel wells when the boat is on water, first wheel locking means to retain the wheel assemblies in the deployed position when the boat is on land, and second wheel locking means to retain the wheel assemblies in the retracted position when the boat is on water.

In at least some embodiments the lever is a single lever. The lever may be positioned approximately in the centreline of the boat. In a preferred form the lever in its second position when the wheels are retracted lies parallel with the floor of the boat on the inside of the boat. In a preferred form the lever in its second position when the wheels are retracted lies in a recess in a floor of the boat inside the boat.

In at least some embodiments the boat also comprises a wheel suspension system associated with the lever. The locking means may comprise a first locking linkage manually connectable to the lever when in the first position maintain it in the first position when the wheels are deployed. The first locking linkage may be resiliently extensible to comprise a spring component of the suspension system. Alternatively (or additionally) the lever may be resiliently flexible and comprise an spring component of the suspension system. In at least some embodiments the hull also comprises left and right additional planing and/or buoyancy portions extending inwardly from the left and right pontoons aft of the transom to provide additional planing area and/or buoyancy to the underside of the hull aft of the transom and/or the left and right pontoons extend rearwardly past the transom for at least 10% of the length of the hull. In a second aspect the invention broadly comprises a boat comprising wheels and a wheel deployment and retraction system comprising :

boat comprising : a hull having left and right pontoons, an underside, and a transom, the underside including a planing surface forward of the transom, left and right wheel assemblies, and wheel wells in the underside of the hull forward of the transom to receive the wheel assemblies, left and right wheels of the left and right wheel assemblies being forward of the transom when the wheels are deployed below the hull of the boat when the boat is on land, wherein : the hull comprises left and right additional planing and/or buoyancy portions extending inwardly from the left and right pontoons aft of the transom to provide additional planing area and/or buoyancy to the underside of the hull aft of the transom, and/or the left and right pontoons extend rearwardly past the transom for at least 10% of the length of the hull.

In at least some embodiments an inwards lateral dimension of the additional planing and/or buoyancy portions aft of the transom decreases away from the transom. In at least some embodiments the left and right pontoons extend rearwardly past the transom for at least 20% of the length of the hull.

The invention aims to provide a new form of towable boat which allows easier launching and retrieving for a boat user than a conventional boat. As the towable boat does not require a separate trailer to carry the boat to and from a launching ramp, the costs of a trailer and parking costs while the boat is in use on the water may be avoided. The boat may also be launched and retrieved on a beach without a vehicle.

Also unlike some amphibious boats which mainly rely on their own motorised wheels for launching and retrieving the boat from the water, the boat of the invention does not have a separate power system for the ground engaging wheels. Therefore the design of the boat is simplified, maintenance requirements are reduced and the overall cost of the boat is reduced.

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. The term "comprising" as used in this specification means "consisting at least in part of". When interpreting statements in this specification which include that term, the features, prefaced by that term in each statement, all need to be present but other features can also be present. Related terms such as "comprise" and "comprised" are to be interpreted in the same manner. This invention may also be said 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 said 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 FIGURES

The invention will now be described by way of example only and with reference to the accompanying drawings of a preferred embodiment, in which :

Figure 1 is a perspective view from above and the rear of a towable boat. Figure 2 is a view of the underside of the hull of the boat with wheel assemblies in a retracted position and parts of the wheel system shown in phantom outline.

Figure 3 is a view from above of the boat with wheel assemblies in a retracted position and parts of the wheel system shown in phantom outline.

Figure 4 is a view from the rear of the boat with wheel assemblies in a deployed position.

Figure 5 is a side view of the towable boat with the wheel assemblies in a retracted position as shown in phantom outline.

Figure 6 is a side view of the towable boat with the mechanical linkage and wheel assemblies in a deployed position. Figure 7 is a perspective partial cut away view from above and the rear of the boat showing the wheel assemblies and mechanical linkage.

Figure 8 is a perspective view from above and the rear of the boat with the wheel assemblies deployed showing the mechanical linkage and suspension means. DETAILED DESCRIPTION

The invention relates to a lightweight towable boat which can either operate as a boat or as a ground engaging towable trailer boat 1. Such dual-mode functionality is enabled by left and right wheel assemblies 7 directly coupled to or integrated with the hull of the towable boat. The wheel assemblies 7 comprise a set of left and right ground engaging wheels 8. In order to retract and deploy the wheels 8 a lever 11 is connected to a mechanical linkage 16 provided between the left and right wheel assemblies 7.

The wheels are generally in a retracted position when the boat operates on the water or in a deployed position to contact a supporting surface to enable the towable boat to be transported on a range of different land surfaces. Referring to Figures 1-3, the exemplary embodiment of the towable boat 1 comprises a rigid hull 2, which includes left and right elongated buoyant pontoons 3, which may be rigid or air inflated. The inside of the hull has a floor surface and the underside of the hull 2 comprises a planing surface. A transom 4 is located across the rear of the hull 2, and a motor for powering the boat, typically an outboard motor, may be located on the transom. The underside of the hull 2 comprises left and right wheel wells 6 for accommodating the left and right wheel assemblies 7, one adjacent to each pontoon 3. Figure 6 shows the wheels 8 deployed to engage the ground. Figure 5 shows the wheels 8 retracted for operation of the boat on water.

As shown in Figure 7, the mechanical linkage 16 comprises shaft 9 across the hull and left and right linkage arms 10a, 10b in the wheel wells, which carry the wheels 8. The shaft 9 and linkage arms 10a, 10b can be manually moved by a lever 11 to deploy and retract the ground engaging wheels 8 beneath the boat. The moveable linkage arms 10a, 10b are connected to the hubs of the left and right wheels 8. The length of the moveable linkage arms 10a, 10b is sufficient to provide clearance for the boat to be towed over a ground surface when the wheel assemblies 7 are deployed .

The shaft 9 passes through the hull 2 of the boat from the internal area accommodating one or more passengers to the wheel wells 6 on the underside of the hull. Seals may be provided around the points where the shaft 9 passes through the hull 2 in order to seal the hull from the water outside. The shaft 9 of the mechanical linkage 16 may be located at the level of the floor of the hull, as shown in Figure 7, or may be located within or beneath (which includes just above) the floor of the hull in the case of the boat being built with an interior floor. In the alternate embodiment where the floor of the hull is comprised by the internal surfaces of the hull 2, the shaft 9 of the mechanical linkage 16 may be located across a portion of the hull towards the base of the hull. The moveable linkage arms 10a, 10b may be simultaneously or individually controlled by a lever 11 which is connected to the shaft 9 of the mechanical linkage 16. The lever 11 is located inside the hull of the boat, and may be placed towards the centre of the hull or towards one side.

In the alternate embodiment mentioned above, the linkage arms 10a, 10b may each connect to separate mechanical linkages and separate levers. In this embodiment the separate levers may be disposed to either side of the hull of the boat, and may be operable independently to raise and lower each of the wheels of the left and right wheel assemblies 7.

In the exemplary embodiment the rotation of the lever 11 causes the linkage arms 10a, 10b and wheel assemblies 7 to move relative to the hull 2 of the towable boat, consequently deploying or retracting the wheel assemblies 7. Rotation of the lever 11 towards the front of the boat causes the wheel assembly to be retracted towards the hull 2 of the boat, and rotation of the lever 11 towards the rear of the boat causes the wheel assembly to be deployed beneath the hull. In the preferred embodiment the lever 11 is connected to the mechanical linkage 16 such that the when the wheel assemblies are in a fully retracted position the lever lies substantially parallel with the surface of the hull. When the wheel assemblies 7 are deployed beneath the hull of the boat the lever 11 is rotated towards the rear of the boat and moveable linkage arms 10a, 10b are rotated downwards as shown in Figure 6. Locking means may be provided to the lever 11 in order to retain the wheel assemblies 7 in either a retracted or deployed position. A first locking means 12 may be provided between the lever 11 and the hull 2 to retain the lever 11 in a position where the wheel assemblies 7 are deployed. The first locking means 12 may act to prevent the wheel assemblies 7 from retracting by preventing the lever 11 from rotating towards the front of the boat. The first locking means 12 may also comprise a portion adapted to prevent further rotation of the lever 11 towards the rear of the boat past its deployed position. For example, this may act to prevent the wheel assemblies 7 from being moved past their deployed position when backing the towable boat over a curb or other obstacle.

A second locking means 13 may be provided on the hull 2 of the boat to retain the lever 11 in a position such that the wheel assemblies 7 are fully retracted. Each of the first locking means 12 and second locking means 13 may be removably connected to the lever 11.

In the preferred embodiment the first locking means 12 which retains the lever and wheel assembly in deployed position also comprises suspension means 14 as shown in Figure 8. The suspension means 14 allows controlled movement of the lever 11, and thus also of the wheel assemblies 7. The suspension means 14 may be a coil spring or other resiliently mounted extensible element. It may also be a resiliently mounted compressible element, such as a cable tension spring, where a compressible spring is mounted in tension in the first locking means 12. Either of these configurations would allow the effective length of the first locking means 12 to increase, allowing controlled relative movement between the hull 2 of the boat and the wheel assemblies 7 to absorb bumps as the boat is towed.

In an alternate embodiment suspension means is provided in the body of the lever 11 while the first locking means 12 remains rigid. In this embodiment the lever 11 or at least a part of it may be formed from a spring-like material such as spring metal or a composite material such as carbon-fibre. In one embodiment the lever 11 may be composed of two or more leaves of spring metal or composite material.

When the wheel assemblies 7 are deployed beneath the hull 2 of the boat, the linkage arms 10a, 10b are rotated downwards from their fixed end at the shaft 9. When the wheel assemblies 7 are in a fully deployed position the rotation of the linkage arms 10a, 10b is such that the wheel assemblies 7 are still located to rear of the shaft 9. When either the first locking means 12 or lever 11 incorporate suspension means, this angle of the linkage arms 10a, 10b allows vertical movements of the wheels 8 to be damped by the suspension. The lever 11 is such that it may be operated by hand by a user without any driven assistance in order to rotate the linkage arms 10a, 10b to retract or deploy the wheel assemblies 7 beneath the boat.

Returning now to the hull 2 of the boat, the exemplary embodiment has left and right elongated buoyant pontoons 3. The pontoons may be rigid or inflated. In the

embodiment shown the hull has pontoons 3 but in an alternative embodiment the hull may be a non-pontoon hull.

The inside of the hull 2 comprises a floor surface. The floor surface may simply be the angled internal faces of the hull 2. However in the exemplary embodiment the floor surface is the upper surface of a substantially flat separate floor which extends across the inside of the hull.

The underside of the hull comprises a planing surface and a set of left and right wheel wells 6 to accommodate the left and right wheel assemblies 7 with left and right wheels 8. The location of the wheels 8 when deployed is such that a majority of the weight of the boat and any motor rests on the wheel assemblies 7 and preferably the front of the boat may be lifted by hand by a user. In the preferred embodiment this weight distribution is achieved by locating the wheel assemblies 7 and wheel wells 6 forward of the transom 4 at the rear of the hull 2.

Aft of the transom 4 the hull further comprises a left and right rear planing portions 5. The left and right rear planing portions extend inwardly (towards the centreline of the hull) from the left and right pontoons. The lower surface of each rear planing portion 5 forms a substantially continuous surface with the underside of the hull 2 forward of the transom, and provides an additional planing surface which compensates for the loss of planing surface at the wheel wells 6. Locating the wheel wells 6 forward of the transom 4 further serves to increase the planing surface at the rear of the boat. With reference to Figure 3, the rear planing portions 5 extend inwardly from the port and starboard pontoons 3 rear of the transom such that a motor may still be accommodated on the transom. In the preferred embodiment the inwards lateral dimension of the rear planing portions 5 decreases towards the rear of the boat. In an alternate embodiment the inwards lateral dimension of the rear planing portion 5 is uniform and runs parallel with the pontoons 3.

Figure 2 shows a bottom view of the towable boat with the wheel assemblies 7 in their fully retracted position. Each ground engaging wheel 8 is fully stowed away in its respective wheel well 6 in the hull. The ground engaging wheels 8 are preferably stowed in a location to reduce their effect on hydrodynamic drag when the boat moves on the water. In the embodiment shown the wheel wells 6 do not have any covering structures such as openable doors or flaps to close the wheel wells 6 when the wheels 8 are retracted.

In another embodiment the wheel wells 6 may be fitted with openable doors to cover the wheel wells when the wheel assemblies 7 are retracted. If such doors or flaps are installed, preferably the surfaces of these components are flush with the bottom surface of the hull to reduce hydrodynamic drag.

As mentioned earlier, the boat can be used as a normal recreational boat on water, or as a ground engaging towable trailer boat during launching, retrieving and transporting of the boat on land surfaces. When the boat operates on the water the wheels are in a stowed position as shown in Figure 5.

When the boat is launched into the water and the wheels 8 are no longer in contact with a ground surface, the first locking means 12 may be disengaged, the lever 11 may be rotated forwards so that the wheel assemblies 7 are in a retracted position. The user may then attach the second locking means 13 to retain the lever 11 and wheel assemblies 7 in a fully retracted position.

To retrieve the boat from the water the second locking means 13 is disengaged from the lever 11 and the lever is rotated rearwardly so that the wheel assemblies 7 are deployed beneath the hull of the boat. The operator may then attach the removable first locking means 12 to retain the lever 11 and wheel assemblies 7 in a fully deployed

position. Once the wheel assemblies 7 are deployed, the boat may be driven or pulled so that the wheels 8 are in contact with the ground surface. The boat may then be pulled from the water by hand or using a vehicle. The bow of the hull 2 may be provided with towing means 15 such as a draw bar to allow the boat to be hitched to a vehicle to be trailed on the road . The towing means 15 may comprise a receiving portion for receiving and coupling with the ball of a trailer hitch.

In the preferred embodiment the towing means 15 is stowed by retracting it inside a waterproof tube in the boat while it is used on the water, and then extended when the boat is to be hitched to a vehicle. A pin or locking device fixes the towing means 15 to the hull 3 in either or both of its retracted and extended positions. In another embodiment the towing means is removed from the boat when it is used on the water.

In addition to the towing means 15 the front surface of the hull 2 or the forward surfaces of the pontoon 3 may comprise handles or other gripping portions to enable an operator to pull the boat from the water.

Where in the foregoing description reference has been made to elements or integers having known equivalents, then such equivalents are included as if they were individually set forth. Although the invention has been described by way of example and with reference to particular embodiments, it is to be understood that modifications and/or improvements may be made without departing from the scope or spirit of the invention as defined in the accompanying claims.