GB2134857A

GB2134857A - Improvements in or relating to watercraft

Info

Publication number: GB2134857A
Application number: GB08403528A
Authority: GB
Inventors: Stanley Gordon Rex Simpson
Original assignee: Individual
Current assignee: Individual
Priority date: 1983-02-11
Filing date: 1984-02-10
Publication date: 1984-08-22
Also published as: GB2134857B; GB8403528D0

Abstract

A watercraft is fitted with at least two axles 30 supporting road wheels, the axles being movable between a lowered position to convert the watercraft into a road vehicle and a raised position wherein the road wheels are wholly contained within the watercraft hull when the watercraft is being conventionally used. Each axle is driven from a common power unit or engine 16 via conventional gearing, prop shafts 32 and transmissions. The watercraft is preferably propelled by a stern drive 17, 18, 20 and steered by a Kort tube. The watercraft preferably has a high speed, low drag hull configuration which is preferably substantially flat bottomed, and an open-fronted depending skirt may be provided to give a hovercraft effect. <IMAGE>

Description

SPECIFICATION Improvements in or relating to watercraft This invention relates to watercraft and is particularly concerned with providing a watercraft capable of high speeds and convertible into a road vehicle.

According to the present invention there is provided a watercraft fitted with at least two axles supporting road wheels, the axles being movable between a lowered position to convert the watercraft into a road vehicle and a raised position wherein the road wheels are wholly contained within the watercraft hull when the watercraft is being conventionally used.

Preferably, each axle is driven from a common power unit or engine via conventional gearing, prop shafts and transmissions.

Preferably each axle is housed in a casing formed with a breathing hole to which is connected a flexible tube.

It is considered that this is desirable due to the fact that, while in water, the axle tends to run relatively cold whereas, when the vehicle is running on land, the axle tends to run relatively hot and the breathing hole assists temperature balance between the casing interior and exterior.

The flexible tube serves to prevent water being sucked into the axle casing.

It is preferred to employ a stern drive for the watercraft. Such engine/drive combinations are well known to those skilled in the art.

It is proposed to modify such known stern drives which conventionally have a vertical shaft between engine and propeller with reduction gearing at the top of the vertical shaft. The modification consists in re-locating this reduction gearing to the bottom of the vertical shaft and by this means it is considered that the B.H.P. of the stern drive can be substantially increased. For example with a known stern drive having a maximum torque of 110 lbs/ft., and reduction gearing of 2 :1, it is considered this modification could almost double the B.H.P. of the stern drive.

It is also provided, by this invention, to drive the watercraft by a water jet drive, again well known to those skilled in the art.

The watercraft may alternatively be provided with a high-speed propeller driven from said common power unit or engine via a power takeoff shaft.

Preferably such propeller shaft is inboard of the rear road axle.

The propeller shaft and road axles are preferably interlinked so that when the latter is lowered into its in-use position the latter are raised to position the road wheels wholly within the watercraft hull, and vice versa.

Such interlinking is, of course, not necessary or possible with a stern drive or a water jet drive, the stern drive simply being pivoted upwards as is conventional.

The propeller and road axles may alternately and separately be clutched into the common power unit or engine save possibly on changeover from watercraft to road vehicle and vice versa.

The propeller shaft and p.t.o. shaft are preferably, as is customary, connected via a universal joint and to avoid undue thrust stresses being applied a two-part hinged bracket surrounds the joint a part being secured to the p.t.o. shaft and the other to the propeller shaft.

The watercraft is preferably steered by Kort nozzles but conventional rudder steering is also envisaged.

The watercraft preferably has a high speed, low drag hull configuration which is preferably substantially flat bottomed.

The watercraft may have a depending skirt, preferably rigid, open at the front to provide a hovercraft effect.

The front road axle is preferably housed in a forward compartment having fore-and-aft watertight bulkheads and a bottom door or flap pivotal up into the compartment when the watercraft is being used as a road vehicle.

The door or flap preferably normally lies in an inclined attitude so that it is open at its leading and trailing edges to create a low pressure vortex as the watercraft moves through the water thus sucking water out of the forward compartment.

A cowl may be provided at or adjacent the front of the hull to direct air under pressure down into the forward compartment to assist removal of water therefrom and also to aerate the layer of water immediately under the hull, and within the skirt if provided, to enhance the speed of the watercraft.

An embodiment of the present invention will now be described, by way of example, with reference to the accompanying drawings, in which: Fig. 1 is a perspective view of a watercraft according to the invention; Fig. 2 is a side view of the watercraft; Fig. 3 is a side view. of the watercraft converted to a road vehicle; Fig. 4 is a detailed view of the propeller shaft and p.t.o. shaft; and Fig. 5 is a diagrammatic view of an alternative road-wheel mounting arrangement.

The watercraft has a substantially flatbottomed, high-speed, low drag hull 10 with a passenger and engine compartment 11 between two watertight bulkheads 1 2 and 1 3.

The forward bulkhead 12 is spaced rearwardly of another watertight bulkhead 1 4 to define between them a compartment 1 5.

It will be manifest that the hull 10 is decked and that a suitable superstructure (not shown) is provided for the watercraft.

An engine 1 6 is provided in compartment 11 and has a power take-off shaft 1 7 connected by a universal joint 1 8 to a propeller shaft 1 9 terminating in a high-speed propeller 20.

In order to avoid undue stressing of the joint 18 ia hinged bracket arrangement 21 surrounds the joint 1 8. This comprises one U-shaped part 22 secured to the power take-off shaft 1 7 and hinged at 23 to another U-shaped part 24 secured to the propeller shaft.

The propeller shaft 1 9 is housed in a tubular casing 25 and a jack or ram 26 is provided for moving the casing 25 and consequently the propeller shaft 1 9 between a raised out-of-use position and a lowered in-use position.

Steering of the watercraft is effected by Kort tube or otherwise.

The compartment 26 rearwardly of the bulkhead 13 is open at the bottom.

The compartment 15, however, is normally closed at the bottom by a door or flap 27 which lies in an inclined attitude so that gaps 28 are provided at its leading and trailing edges.

This door or flap 27 is, when the watercraft is converted to a road vehicle, moved clear of the bottom of the compartment 1 5 (see Fig. 3). It is envisaged that this door or flap 27 may be omitted.

A cowl 29 is provided at the front of the hull 10 and opens into the compartment 15.

In each compartment 1 5 and 34 is a road axle 30 mounting road wheels 31.

These axles 30 are connnected, in customary manner, by prop shafts 32 and gearing (not shown) to the engine 1 6. Each axle 30 is consequently driven, i.e. four wheel drive. The front axle 30 is fitted with the usual steering gear.

These axles 30 and road wheels 31 are contained wholly within the hull 10 when not in use as can be seen from Fig. 2 so that they cause no resistance to movement of the watercraft through the water.

The axles 30 are raised and lowered by suitable means shown diagrammatically at 33.

It will be manifest that when the propeller shaft 1 9 is lowered the road axles are raised, and vice versa save at the time on conversion from watercraft to road vehicle, and vice versa, when both for a short period of time will be lowered.

This also is the only time both will be clutched into the engine 1 6.

As the watercraft moves through the water, a low pressure vortex is created at gaps 28 so that water is expelled from compartment 1 5. At the same time air under pressure passes via the cowl 29 into the compartment 1 5 assisting the egress of water and providing an air cushion under the hull. If an open-fronted depending rigid skirt is provided this air cushion creates a hovercraft effect.

In Fig. 5, it can be seen that each road wheel 31 is carried by an A-frame 35 pivoted at locations 36 and operable, for example, by a hydraulic ram 37. Collapse of the A-frame 35 under hydraulic action elevates the road wheel 31 which is lowered into ground contact by reverse action of the hydraulic ram 37. A stern drive is indicated at 38.

It is to be noted that the watercraft has no watertight doors which means that the hull is of simple construction and can be produced at relatively low cost.

The watercraft/road vehicle may be used for leisure purposes, or as an inshore lifeboat (in this case it would be fitted with appropriate life-saving equipment) or as a foam spreader vehicle at airports particularly when same are located adjacent the sea or other body of water. It may have military usages or be employed to fight oil pollution.

The fuel tank for the watercraft will generally be located in compartment 34 with various lighting equipment at the rear of the watercraft. It is envisaged that an impact or isolation switch (not shown) would be disposed inboard of bulkhead 13 so that in the event of a rear collision all electrical power in the region of the petrol tank would be immediately cut off by the impact switch to reduce the risk of fire. Secondary lighting would be provided forwardly of bulkhead 13.

The watercraft, due to its construction, lends itself to easy rear loading.

It is considered that a 27 ton watercraft according to the invention could generate 200 B.H.P. giving a speed of about 20 knots.

Claims

1. A watercraft fitted with at least two axles supporting road wheels, the axles being movable between a lowered position to convert the watercraft into a road vehicle and a raised position wherein the road wheels are wholly contained within the watercraft hull when the watercraft is being conventionally used.

2. A watercraft as claimed in claim 1, in which each axle is driven from a common power unit or engine via conventional gearing, prop shafts and transmissions.

3. A watercraft as claimed in claim 2, in which each axle has a housing provided with a breathing hole to which is attached a flexible tube.

4. A watercraft as claimed in any one of claims 1 to 3 adapted to be driven by a stern drive.

5. A watercraft as claimed in claim 4, in which the stern drive has reduction gearing at the propeller-adjacent end of its vertical transmission shaft.

6. A watercraft as claimed in any one of claims 1 to 3 adapted to be driven by a water jet or pulse motor.

7. A watercraft as claimed in any one of claims 1 to 3, comprising a high-speed propeller driven from said common power unit or engine via a power takeoff shaft.

8. A watercraft as claimed in claim 7, in which the propeller shaft is inboard of the rear road axle.

9. A watercraft as claimed in claim 7 or 8, in which the propeller and road axles are interlinked so that when the latter is lowered into its in-use position the latter are raised to position the road wheels wholly within the watercraft hull, and vice versa.

10. A watercraft as claimed in any one of claims 1 to 9 adapted to be steered by a Kort tube.

11. A watercraft as claimed in any one of claims 1 to 10 having a high-speed low drag hull configuration which is substantially flat bottomed.

12. A watercraft as claimed in claim 11, in which the hull has a depending open-fronted skirt to provide a hovercraft effect.

13. A watercraft as claimed in any one of claims 1 to 12, in which the front road axle is housed in a forward compartment having foreand-aft watertight bulkheads and a bottom door or flap pivotal up into the compartment when the watercraft is being used as a road vehicle.

14. A watercraft as claimed in claim 13 in which the door or flap normally lies in an inclined attitude so that it is open at its leading and trailing edges to create a low pressure vortex as the watercraft moves through the water thus sucking water out of the forward compartment.

15. A watercraft as claimed in claim 13 or 14 in which a cowl is provided at or adjacent the front of the hull to direct air under pressure down into the forward compartment to assist removal of water therefrom and also to aerate the layer of water immediately under the hull, and within the skirt if provided, to enhance the speed of the watercraft.

1 6. A watercraft, substantially as hereinbefore described with reference to the accompanying drawings.