AU700280B2 - Amphibious sailing craft - Google Patents

Description

AUSTRALIA

Patents Act 1990 COMPLETE SPECIFICATION STANDARD PATENT APPLICANT: SHIMELD, Stuart Danes ADDRESS: 66 Government Road, Nords Wharf, NSW ACTUAL INVENTOR: Stuart Danes SHIMELD ADDRESS FOR SERVICE: Paul A Grant and Associates PO Box Fisher, ACT 2611 INVENTION TITLE: AMPHIBIOUS SAILING CRAFT ASSOCIATED PROVISIONAL: PN4336 filed on 25 July 1995 The following statement is a full description of this invention, including the best method of performing it known to me:i TECHNICAL

FIELD

This invention relates to amphibious sailing craft, such as those like dinghies or skiffs used in sport-sailing. It may be applied, however, to smaller craft more like sailboards or to larger craft more like trailer-sailers. The invention is applicable to i 5 single-hulled craft as well as to multi-hull craft.

BACKGROUND TO THE INVENTION Land-yachts having sails and wheels or skids are well known. Many proposals have also been advanced for wheeled sailboards for use on land, mostly using essentially the same rig as have been developed for sailboards designed for use on water.

These craft have been configured like scooters, tricycles or as four-wheel vehicles.

It is normal for land-yachts (rather than sailboards) to use the tricycle configuration having a single forward str 'rable wheel. This allows the sailor to be located well aft and to windward of the centre-line to maximise stability. Examples of land yachts 15 and land-based, wheeled sailboards may be found in the following patents or applications: PCT/EP87/00802, PCT/AU94/00588, PCT/GB91/01474 and Australian application Nos 47667/85, 15973/91 and 61298/87. None of these land yachts are able to sail on water, however.

:l 20 Wheeled land-yachts are often sailed along beaches at low tide, but unless the wind is particularly favourable, it is generally only possible to sail for any distance in one direction because the strip of hard sand along the water's edge is generally quite narrow making it impractical to tack back to the start.

25 While sports-oriented sailing craft exhibit a great variety of rigs and hull configurations, few can be sailed off the water and onto the beach without damage. It is generally out of the question to sail dinghies or skiffs onto the beach. Sailboards are often sailed in-shore until they contact the sand so that the sailors can step off the craft and walk ashore with it. The large area of the flat hull, combined with the fixed stern fins make it generally impossible to travel more than a metre or two onto the sand. Similarly, small catamarans without centre-boards and with flip-up rudders can be sailed onto the beach from the water but also cannot travel far. Of course, once a craft is beached in this way, it is essentially uncontrollable.

3 I am not aware of any amphibious sailing craft of the sports type that can be sailed along the sand of a beach, into the water and, if desired, onto the beach again.

OBJECTIVES OF THE INVENTION It is an object of the present invention, therefore, to provide amphibious sailing craft which are controllable on both land and sea. It is desirable that the principles of this invention be applicable to light-weight craft of the sport-sailing type that can be sailed by one or two people. Such craft can be sailed down a beach on a reach, turned into the water and then tacked back and forth up-wind like a normal sailing boat until it returns to the starting-point on the beach.

OUTLINE OF INVENTION Basically, the present invention comprises a sailing craft fitted with retractable wheels which can be raised when the craft is sailing in the water and lowered when it is sailing on land. Preferably, but not essentially, the craft has at least one stern wheel that is coupled to the rudder so that it is raised as the rudder is lowered and vice versa, the stern wheel being capable of being steered (when lowered) in a similar manner to the rudder (when lowered).

From one aspect, the present invention comprises a sailing craft having a hull or hulls of sufficient buoyancy to support itself, the craft's rig and its occupants on water, wheels mounted on said hull or hulls so that they can be lowered to a first position in which they are adapted to support the craft from the ground and so that they can be raised to a second position in which they are substantially above the 25 waterline when the craft is afloat.

toB From another aspect, the invention comprises a wheeled sailing craft having a tiller and a rudder for steering the craft when it is afloat and having one or more wheels connected to the tiller, so that said wheel or wheels can be steered when the craft is on land by operating the tiller in substantially the same manner as when the craft is being sailed on the water. This arrangement can allow the craft to be tuned so as to head-up upon heeling in substantially the same manner whether on land or in the water.

From another aspect, the invention comprises a sailing craft having lowerable wheels for vehicular transport on land and at least one buoyant hull fitted with a lowerable rudder and/or centreboard for sailing on water, and means inter-connecting at least one of said wheels and the rudder and/or centreboard operable to lower the rudder and/or centreboard as one or more wheels are raised and to raise the rudder and/or centreboard as one or more wheels are lowered.

From yet another aspect, the invention comprises a wheeled mono-hull sailing craft capable of sailing on land having a forward sub-frame extending athwart the craft forward of the mast and supporting at least one forward wheel on each side of the craft, and a stern sub-frame extending aft of the transom and pivotally supporting at least one stern wheel arranged centrally of the craft. Such a craft will normally have a hull-skin with the profile of a sailing dinghy or skiff and it will be generally preferable to provide a central frame which structurally links the forward sub-frame with the stern sub-frame so as to provide longitudinal and torsional stiffening for the hull-skin between said sub-frames.

From another aspect, the invention comprises a wheeled catamaran sailing craft 1. o capable of sailing on land and having: one cross-beam forward of the mast and 420 another at or near the stern, a raiseable (or retractable) wheel supported from each end of each beam, means for steering the forward pair of wheels and/or the aft pair of wheels when lowered. The steerable wheels may be linked to the tiller (or its cross-arm) so that the craft can be steered in the normal manner when on land or in the water.

It generally will be convenient to mount each wheel in a fork and to mount the fork in turn on a shaft that is rotatably located within the cross beam. The wheels and their forks may be mounted on either end of a common shaft that runs the full length of the beam or they may be mounted on separate short shafts, each located in the outer part of the cross-beam. The former arrangement offers the advantage, particularly in monohull craft, that both wheels and their forks can be raised or lowered by turning the common shaft at a single point near its centre. However, such an arrangement normally requires the cross-beam to be cut in order to gain i

I

to 1-1access to the shaft, though the beam need not be completely severed. In a catamaran, it may not be acceptable to weaken the cross-beam in this manner and it may therefore be necessary to raise and lower the wheels by a mechanism which turns the shaft (or shafts) from one (or both) ends of the beam at or near the fork of the respective wheel, rather than at its centre.

The wheel forks may be pivoted (for steering) around a generally vertical axis (as in the front wheel of a bicycle or a motorbike) and may include telescoping shock absorbers (as in some mountain bikes and in most motorbikes). As in bicycles, the 10 pivot axis of the fork may be inclined to the vertical so as to provide a castor angle.

Where, as will be convenient in the case of a monohull, a non-steerable wheel is mounted in forks on the ends of a common shaft held within a cross-beam, the forks can either be rigidly attached to the shaft or they can be pivoted so as to act as castors (within limited angles).

DESCRIPTION OF EXAMPLES Having broadly portrayed the nature of the present invention, an example will now be described by way of illustration only. In the following description, reference will be made to the accompanying drawings in which: Figure 1 is a general side elevation of an amphibious skiff formed in accordance with this invention, Figure 2 is a general bow-end elevation of the skiff of Figure 1, Figure 3 is a general stern-end elevation of the skiff of Figure 1, #0 0 CD Figure 4 is a general plan view of the hull of the skiff of Figure 1, Figure 5 is a side elevation of the hull-frame and wheel-support system employed in the skiff of Figure 1, 6 Figure 6 is a stern-end elevation of the hull-frame and wheel-support system employed in the skiff of Figure 1, Figure 7 is a similar view to that of Figure 6 showing the mechanism for raising and lowering the front wheels in more detail, and Figures 8A, 8B and 8C are respectively a plan and two side elevations showing an alternative mechanism for raising and lowering the stern wheel and rudder, the side elevations being taken on views B and C respectively.

The chosen example relates to an amphibious skiff with a tricycle wheel arrangement having two non-steerable and non-castor front wheels and a single centrallymounted, steerable rear wheel. This skiff is generally illustrated in the elevations of Figures 1 to 3 and the plan of Figure 4 and basically comprises a hull 10, mast 12, bowsprit 14, centreboard 16, rudder 18 and boom 20. In Figure 1, the skiff is shown fully-rigged with mainsail 22, jib 24 and spinnaker 26. The gunwales of hull 10 are formed as 'wings' 28 from which the sailor can trapeze, as is well known in skiffs.

In this embodiment, the skiff has a foredeck 30 which covers the most of the hull fC forward of mast 12, but the cockpit 32 (Figure 4) is open. As depicted in Figures 1- 20 4, the skiff is configured for sailing on land and, therefore, centreboard 16 and rudder 18 are shown in their raised positions; their lowered positions used for watersailing being shown in broken lines respectively at 16a and 18a.

A pair of front wheels 34 are carried on forks 36 fixed to the ends of a transverse shaft 38. As shown in full lines in Figures 1-4, wheels 34 and forks 36 are arranged in the lowered position for sailing on land, the raised positions of the wheels and forks employed for sailing on water being shown in broken lines at 34a and 36a. The transition from lowered to raised position of front wheels 34 is simply achieved by the rotation of shaft 38 in a manner which will be described below.

In this embodiment, a single rear wheel 40 is mounted for pivotal movement about a horizontal shaft 42 on forks 44, forks 44 being rigidly connected to rudder 18 so that, when rudder 18 is swung down into position 18a, wheel 40 is moved from its 74 lowered position (as shown in full lines) to its raised position 40a (shown in broken lines). The rudder and stern wheel are attached to transom 46 by a sub-frame 48 and the whole sub-assembly is pivoted about vertical rudder post 50 (Figure 4) to effect the steering of the craft (on water or land) by the use of a conventional tiller arm 52 (shown in broken lines in Figure 1 but best seen in Figure Figures 5 and 6 show the way in which the skiff is strengthened by internal framing for sailing on land. In this embodiment, the frame is formed by welding from aluminium alloy tubing and is affixed to the plywood or fibreglass skin of hull 10 by fibre-reinforced epoxy cement as is well known in the construction of skiffs. A subframe 54 of generally tetrahedral shape is used to strengthen the bow, extending downwards and centrally to meet the keel-line at 56 directly below the mast 12, a short central vertical tube 58 being arranged between the mast-step and point 56 on the keel-line. An aft sub-frame 60, also of generally tetrahedral form, is employed to strengthen the transom 46 (not shown in Figure the fore and aft sub-frames being linked into one structure by a pair of central tubes 62 that is braced by tubes 64 and 66 to point 56 and sub-frame 54 respectively.

Since rudder 18 and rear wheel 40 are fixed together for pivotal rotation about shaft I 20 40, either one can be raised or lowered simply and directly by the sailor, simple locking means (not shown) being provided to hold the rudder/wheel in the lowered/raised position. Preferably, the locking means are such that the rudder 18 and wheel 40 can be locked in an intermediate position where both are 'half up'. It will be convenient to transport the skiff on its trailer with the rudder and rear wheel in this position.

The raising and lowering of front wheels 34 is, however, more difficult to accomplish.

While many solutions to this problem are possible within the scope of this invention, ,r 9that chosen for this example is best seen from Figure 7. Shaft 38, to which forks 36 (not shown in Figure 7) are attached, passes though a tubular cross-beam 70 that is cut away in the centre to allow access to shaft 38. As shown in Figure 7, centreboard 16 is in its raised position and wheels 34 in their lowered position.

Centreboard 16 may be lowered by pulling on lines attached to its nose 74 to swing 8 it around its pivot-pin 76 (Figure 5) to bring it into position 16a shown in broken lines in Figures 5 and 1. The centre of a heavy shock cord 78 is attached to centreboard nose 74 and its ends are wound around shaft 38 in such a manner that shaft 38 is rotated (or biased to rotate) to raise wheels 34 to positions 34a when centreboard 16 is lowered by pulling on lines 72. This rotation of shaft 38 is, however, prevented by a count-pull on shaft 38 exerted by rope or wire 80 which is paid-out or drawninto a 'magic-box' 82 that is, in turn, controlled by pull-lines 84. [A magic-box is simply a boxed pulley system offering a large mechanical advantage, such as 10:1, which is suitable in this case.] Locking means (not shown) may also be used to positively lock shaft 38 when the wheels are in the down position.

The arrangement of shock-cord 78 is such that, even with wheels 34 and centreboard 16 both up, there will be sufficient tension in the cord to bias the wheels in their raised position. However, it will be desirable to incorporate locking means which allow both the wheels and the centreboard to be safely stowed in their raised positions for transport.

Figures 8A, 8B and 8C illustrate an alternative mechanism for raising and lowering o. the stern wheel and rudder. In this case, the rudder'box' is formed from a triangular frame comprising a bifurcated tiller arm 100, the forks of which are joined at the rudder post 102 and extend rearwards and downwards therefrom, (ii) a bifurcated lower arm 104 which is also joined at the rudder post 102, the forks 100a of which slope upwards and rearwards therefrom, and (iii) a pair of large bearing rings 106 that join the rear ends of the corresponding forks 1 00a and 104a. A large diameter shaft 108 is mounted for rotation within bearing rings 106 and carries the rudder 110 and the forks 112 between which the wheel 114 is mounted. A gear segment 116 is formed around the head of rudder 110 so as to be concentric with shaft 108, the o segment being flared outwards at each extremity to form a curved stop or rest 118.

A gear pinion 120 is mounted on a secondary shaft 122 that is, in turn, mounted in bearings (not shown) fixed to the upper face of each fork 100a. A winch-drum 124 is mounted on one end of shaft 122 so that, when winch-cord 126 is pulled from its cleat 128 at the forward end of tiller arm 100, drum 124 and shaft 122 are rotated counter-clockwise so that pinion 120 raises rudder 110 (by meshing with gear segment 116) and lowers wheel 114 until the upper rest 118 is brought against pinion 120. This movement of the wheel and rudder will be relatively easy to effect when the craft is sailing in water because the wheel will be heavier than the rudder at least initially and (ii) the wheel will be swung downwardly and to the rear by the force of the water. The upper recess 118 provides a solid stop for the rearward movement the wheel; that is, one having sufficient strength to resist the rearward drag of the rear wheel the craft is sailing on land.

To raise wheel 114 and lower the rudder 110 after the craft re-enters the water requires more force as the lowered wheel will be dragged backwards by the water.

Accordingly, a rack-and-pinion system with a 'magic-box' is used for this purpose.

Referring again to Figures 8A to 8C, the rack 130 is slidingly mounted on or in one of the forks 100a and arranged to engage a pinion 132 that is fixed to the opposite end of the counter-shaft 122 to that on which the winch drum 124 is mounted. Thus, to raise wheel 114, rack 130 is pulled rearwards by a chord or wire 134 which is lead around a pulley 136 at the rear extremity of fork-arm 11 Oa, the chord or wire being led along arm 110Oa to a magic-box 138 mounted on or in the tiller-arm 100. The o 0C pull-chord 140 from magic-box 138 is led forwards through a cleat 142 to the front S: 20 end of the tiller arm 100 so that it is convenient for the sailor to grasp.

In operation, the skiff may be transported to the beach on its trailer, as is normal, its rear wheel being 'half-up' and its rudder being 'half-down' to clear the road while the front wheels are conveniently 'full-up'. At the beach the rear wheel is lowered to the full-down position (so that the rudder is full-up) and the front wheels are also placed in their full-down position. Conveniently, the trailer is so proportioned that the craft is then supported by its wheels so that it can be wheeled off the trailer and to a ;suitable place for rigging. After rigging, the craft can be sailed on ground as desired :and then steered into the water where, once afloat, its front wheels can be raised while its centre-board is simultaneously lowered, and its rear wheel can raised while its rudder is simultaneously lowered.

The manner in which the wheels, rudder and centreboard are manipulated will now t.ci described in more detail having regard to the first example of the invention (described with respect to Figures 1 to Shaft 38 is unlocked from its transport position and rotated by the use of magic-box 82 to lower front wheels 34 and tension shock-cord 78 and, if desired, the shaft may be locked in this position. The skiff can then be wheeled from the trailer and onto the beach where it can be rigged. After rigging, it can be sailed along the beach on its wheels using tiller 52 in the normal i manner. To return to its starting point, the skiff may then be sailed into the water until it is floating, adequate steerage being provided for this purpose by rear wheel 40. Then, shafts 38 and 42 are unlocked (if necessary), rudder 18 is lowered into position and rear Aheel 40 is raised; lines 84 are released removing tension from line 80 on shaft 38 and, finally, centreboard 16 is lowered by pulling on lines 72, Srotating shaft 38 to raise wheels 34 to positions 34a. The skiff may then be sailed and tacked in the normal manner on water.

The manner in which the rear wheel and rudder are manipulated will now be described in more detail having regard to the second example of the invention (described with respect to Figures 8A to 8C), the manipulation of the front wheels I, and centreboard being unchanged. To lower the stern wheel 114, chords 126 and 9' 20 134 are released from cleats 128 and 142 respectively chord 134 is pulled to 4 contract magic box 138 and pull rack 130 rearwards, turning pinions 132 and 120 in the anticlockwise direction (Figure 8B) to raise rudder 110 and lower wheel 114 f until the upper recess 118 engages pinion 122 to lock the wheel and rudder in position. Finally chord 134 is fixed in cleat 142 and chord 126 is pulled tight to take up the slack in that chord. To raise the wheel 114 and lower rudder 110, the procedure is simply reversed.

,W hether the skiff is sailing on water or on land, it is possible for the sailor to use 'reaching straps' (not shown) to lean-out and balance the boat or, if there is sufficient wind, to attach a trapeze wire and stand on wings 28 to balance the boat. The skiff is thus steered and sailed in substantially the same manner whether it is on water or on land.

While the examples provided embody the objectives of the invention, those skilled in the art will appreciate that many modifications may be made without departing from the scope of the invention outlined above. As indicated earlier, an amphibious catamaran or sailing dinghy can be made in accordance with the invention. It will also be appreciated that the fore-and-aft level of the boat on level ground need not be the same as in still water. Depending upon the rig employed, it may well be desirable to arrange the stern of the craft to be lower on land than in the water so as to effectively increase the rake of the mast as an insurance against cart-wheeling in the event that the front lee-side wheel digs into soft sand. These and many other adjustments can be readily made without departing from the invention.

o fi 9 a o D St Paul A Grant Date for Stuart Danes Shimeld 11 While the examples provided embody the objectives of the invention, those skilled in the art will appreciate that many modifications may be made without departing from the scope of the invention outlined above. As indicated earlier, an amphibious catamaran or sailing dinghy can be made in accordance with the invention. It will also be appreciated that the fore-and-aft level of the boat on level ground need not be the same as in still water. Depending upon the rig employed, it may well be desirable to arrange the stern of the craft to be lower on land than in the water so as to effectively increase the rake of the mast as an insurance against cart-wheeling in the event that the front lee-side wheel digs into soft sand. These and many other adjustments can be readily made without departing from the invention.

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Claims (1)

1. 4. 4 0 a. a o 0. o a 4 4* o 4 The following statement is a full description of this invention, including the best method of performing it known to me:- 14 ABSTRACT An amphibious sailing craft is disclosed which has wheels which can be lowered to allow the craft to be sailed on land, the rear wheel or wheels of the craft preferably being steered using the same tiller arm as used to turn the rudder when sailing. One example (Figure 1) is a skiff having a tricycle wheel arrangement, the craft basically comprises a hull mast bowsprit centreboard rudder (18) and boom A pair of front wheels (34) are carried on forks 36 fixed to the ends of a transverse shaft (38) that passes through the hull Transition from the lowered to the raised position (34a) of front wheels is simply achieved by the rotation of the shaft A single rear wheel (40) is mounted for pivotal movement about a horizontal shaft (42) on forks (44) which are rigidly connected to the rudder (18) so that, when the rudder (18) is swung down (18a), the rear wheel (40) is moved from its lowered position to its raised position (40a). The rudder and stern wheel are attached to the boat transom (46) by a sub-frame (48) and the whole sub-assembly is pivoted about vertical rudder post to effect the steering of the craft on water or land by the use of a conventional tiller arm (52). I i 0 0 4 Ct