TAKE APART WATER CRAFT

FIELD OF THE INVENTION

This invention relates to watercraft which can be taken apart to facilitate transport out of the water.

BACKGROUND OF THE INVENTION

It is well known to design rowing shells, kayaks, tender boats and other watercraft so that they can be disassembled into a number of sections which make them easier to transport. The age old technique for achieving this is to provide each demountable section with reinforced bulkheads which are bolted together in order for the craft to be assembled for use on the water.

However the bolting together operation takes time and the bolts are subjected to high stress and failure due to repeated fastening and unfastening. Further the bolt holes deteriorate and sealing between bolted bulkjieads often fails and allows water to enter the craft.

There have been numerous attempts to overcome these problems by providing sealing interfaces between demountable sections and by simplified locking mechanisms. A number of these designs are discussed in Australian Innovation Patent 2004100379B which has been examined and certified and which discloses a dovetailing interface with top mounted locking ties spanning adjoining bulkheads.

Although this design represents an improvement in sealing and locking demountable sections, it is complicated to mould and is still difficult to assemble. For example the dovetailing slots need to be aligned precisely and the multiple locking ties are secured by screw bolts which will only engage when the sections are accurately aligned.

OBJECT OF THE INVENTION

It is therefore an object of the present invention to provide a take apart design which is simple to mould, robust and easy to assemble, or at least provides a useful alternative to the prior art devices.

STATEMENT OF THE INVENTION

According to the present invention a water craft comprises two or more sections with mating bulkheads and a tensioning device extending from bow to stern and passing through said bulkheads such that the tensioning device holds the bulkheads together for use on the water.

Preferably the mating bulkheads have inwardly and outwardly tapering ridges which guide the bulkheads into locking engagement as the tensioning device draws the sections together.

Preferably the tensioning device is a strap which is attached internally to the bow and stern of the craft and is tensioned by a ratchet.

Alternatively the tensioning device is a cable attached internally to the bow and stern of the craft.

Preferably the attachment of the tensioning device is by hooks or shackles at each end of the strap or cable which engage brackets attached to the inside of the bow and stern of the craft.

Alternatively the tensioning device is tensioned by a threaded tumbuckle or an over-centre load binder.

Preferably the tensioning device passes through holes in the bulkheads which are above the waterline of the floating craft.

Preferably the sections of the water craft have a floor which prevents the entry of water from above to below the waterline of the craft.

Alternatively the tensioning device extends from bow to stern external to the hull of the craft and is retained at the level of the centre of buoyancy of the craft.

Preferably the craft is molded from fiberglass or polyethylene.

BRIEF DESCRIPTION OF THE DRAWINGS An embodiment of the invention is now described by way of example only with reference to the accompanying drawings in which: Fig 1 is a an exploded perspective view of a take apart kayak Fig 2 shows the detail of interfacing bulkhead sections of the kayak of Fig 1 Fig 3 is an exploded view of a four section two man kayak Fig 4 is an exploded view of a tender boat and

Fig 5 is a view of a kayak with an external tensioning device.

DETAILED DESCRIPTION OF THE INVENTION Fig 1 shows interfacing bulkheads 1, 2 of a three section kayak. Bulkheads 1 have inward tapering ridges while opposing bulkheads 2 have outward tapering ridges. Accordingly when the sections are brought together the tapered ridges first align mating bulkheads 1 , 2 which then fit securely into one another eliminating movement between bulkheads 1,2 in both vertical and lateral directions.

Tensioning strap 3 is used to draw the three sections together and to apply a compressive force which locks them in sealing engagement. Strap 3 has hooks 5 at each end which engage brackets 4 molded into the bow and stern of the kayak. Ratchet 6, accessed through hatch 7, is used to tension strap 3 so that the compressive force between the bulkheads is greater than the separating forces in the water.

Tensioning strap 3 passes through holes 8, 10 in bulkheads 1 , 2 which are above the normal waterline. Accordingly even if there is some parting of bulkheads 1 , 2 and water enters the space between them it will not eηter the kayak through holes 8, 10. The space below the waterline is sealed against the entry of water from above by floor 9.

Tensioning strap 3 could be replaced by a cable and ratchet 6 could be replaced by a threaded turnbuckle or an over centre load binder. Strap 3 could be enclosed in a tube with the tensioning device located in a break in the tube located in the centre section. The sections of the kayak can be molded from fiberglass, polyethylene or any other material which can withstand the compressive forces created between bulkheads 1 , 2 by tensioning strap 3.

This tensioning design can also be applied to a wide range of other water craft. For example Fig 3 illustrates a four section two man kayak and Fig 4 illustrates a three section tender boat or dingy which utilise similar mating bulkheads and tensioning devices.

Fig 5 illustrates an alternative form of the invention in which tensioning strap 3 extends from bow to stern external to the hull of the kayak and is retained in a groove 11 at the level of the centre of buoyancy of the, craft. Accordingly the upward buoyancy forces attempting to separate the bulkheads under the water are resisted by the tension in strap 3 as occurs with the internal strap 3 in Fig 1.

VARIATIONS

It will be realized that the foregoing has been given by way of illustrative example only and that all other modifications and variations as would be apparent to persons skilled in the art are deemed to fall within the broad scope and ambit of the invention as herein set forth. Throughout the description and claims of this specification the words "comprise" and variations of that word such as "comprises" and "comprising" are not intended to exclude other additives components integers or steps.