GB2213435A

GB2213435A - Multihull assembly mechanism

Info

Publication number: GB2213435A
Application number: GB8728706A
Authority: GB
Inventors: James Labouchere
Original assignee: Individual
Current assignee: Individual
Priority date: 1987-12-09
Filing date: 1987-12-09
Publication date: 1989-08-16
Also published as: GB8728706D0

Abstract

In order for the outer hulls 8 of a multihull to fold inward to reduce the craft's beam when disassembled, the outer hulls 8 are attached on hinges 5 to cross-beams 2 on opposite sides of the central longitudinal axis of the craft. Opposite cross-beams are connected at their inner ends to common hinged attachments 4 which allow the cross-beams to pivot from an extended position FIG 1 to a folded position. The structure is braced with tensile members 6 for rigidity, and to allow the beams to fold inward, an assembly carrying any pair of bracing attachments moves parallel to the longitudinal axis of the craft and relative to the hinged cross-beam attached 4, allowing the cross-beams to rotate inward without releasing bracing. <IMAGE>

Description

MULTIHULL ASSEMBLY MECHANISM This invention relates to a mechanism for the quick assembly of a multihull waterborne craft.

Dinghy sailing has become very popular in the last few decades and dinghy parks are in many places over-crowded. For similar lengths of boat, multihulls take up far more space than monohulls, and consequently have been banned from many dinghy parks. It is desirable to have a multihull that dismantles or folds quickly and easily for compact storage and ease of transport.

According to the present invention there is provided a waterborne craft with structure joining two or more hulls, having a pair of cross-beams on opposite sides of the central longitudinal axis of the craft, the cross-beams connected at their inner ends to a common hinged attachment which allows the said pair of crossbeams to pivot from an extended position with their outer ends substantially displaced from the central longitudinal axis, to a position with the distances between the cross-beams' outer ends and the cenrral longitudinal axis substantially reduced; an assembly being free to move relative to the said hinged crossbeam attachment but constrained to a locus substantially parallel to the central longitudinal axis, said assembly containing at least one bracing attachment point attached to a tensile member bracing the craft for rigidity, allowing the said bracing member to become slack which in turn enables the cross-beams to rotate in toward the said central axis.

A specific embodiment of the invention will now be described by way of example with reference to the accompanying drawings in which: Figure 1 shows in perspective, the assembled multihull.

Figure 2 shows the multihull in its folded position (the mast, rudder assemblies and rigging are not illustrated in Figure 2, though they may remain attached when the craft is rigged and derigged).

Referring to the drawing the main structure of a foldable multihull comprises a central beam 1 mounted parallel to the central longitudinal axis of the craft, a pair of hulls 8, two pairs of parallel cross-beams 2,3 each hinged at one of its ends on attachments 4 on the central beam and at the other end hinged on attachments 5 on the hulls, external bracing members consisting of cables 6 and struts 12 that give the structure rigidity when the craft is rigged.

As shown in Figure 1, in removing pins 9 the cross-beam attachments 4 to the central beam are able to slide along the central beam in the direction of arrow 10 allowing any bracing providing the cross-beams with rigidity about the axes of the hinges on which the cross-beams are mounted, to go slack, enabling the crossbeams to rotate to a position parallel to the central beam, as shown in Figure 2.

The cross-beams are also hinged at the attachment points 5 on the upper surfaces of the hulls on the inboard edges. The crossbeams continue over the top surface of the hulls and lock into hooks 12 rigidly attached to the outside edge of the hulls. ks the craft is rigged and the crossbeams rotate to their extended positions they lock into the hooks, thus providing the hulls with torsional rigidity relative to the cross-beams.

For bracing the aft cross-beams 3 against rotation about the longitudinal axis the strut 12 is used to displace the attachment points vertically. The mast 13 is used to brace the forward cross-beams 2, and in turn, this gives the mast rigidity about the longitudinal axis. A detachable beam 14 extends forward of the mast base 15 providing a third attachment point for the mast bracing.

When the mast bracing is slack during rigging or derigging the mast base may be lifted on or off a short stub which is used to locate the base of the mast on the central beam.

A central hull (not illustrated) may be mounted on the central beam, and rudders 16 and tillers 17 may be mounted on any one of the hulls. They may be interconnected by way of a link 18 to provide similar control movements on each rudder.

The outboard hulls may be asymmetrically cambered for optimum performance on opposite tacks, and keels may be fitted detachably to any of the hulls.

A canvas trampoline 19 may be fixed between the central beam, aft cross-beam and a bracing wire 20 attached to the two beams, providing accommodation for the crew.

Handling points and attachment points for a launching trolley and towing trailer may be provided (not illustrated).

Claims

1. A waterborne craft with structure joining two or more hulls, having a pair of cross-beams on opposite sides of the central longitudinal axis of the craft, the cross-beams connected at their inner ends to a common hinged attachment which allows the said pair of cross-beams to pivot from an extended position with their outer ends substantially displaced from the central longitudinal axis, to a position with the distances between the cross-beams' outer ends and the central longitudinal axis substantially reduced; an assembly being free to move relative to the said hinged cross-beam attachment but constrained to a locus substantially parallel to the longitudinal axis, said rigid assembly containing at least one bracing attachment point attached to a tensile member bracing the craft for rigidity, allowing the said bracing member to become slack which in turn enables the cross-beams to rotate in toward the central axis.

2. A craft as claimed in Claim 1 wherein a hull is attached to a cross-beam on a hinge which enables the hull to rotate relative to the cross-beam about an axis substantially parallel to the axis about which the cross-beam rotates relative to the central longitudinal axis.

3. A craft as claimed in any one of the preceding claims wherein the said hull locks so that it cannot rotate about its longitudinal axis relative to the cross-beams.

4. A craft as claimed in any one of the preceding claims wherein a cross-beam locks in a hooked device attached rigidly to the said hulls as the cross-beams lock into their extended positions.

5. A craft as claimed in any one of the preceding claims wherein two cross-beams mounted on a side of the craft substantially parallel to each other provide forward and aft attachments for a hull.

6. A craft as claimed in any one of the preceding claims wherein a central beam is mounted parallel to the central longitudinal axis of the craft, the said hinged cross-beam attachments being able to slide along the said central beam.

7. A craft as claimed in any one of the preceding claims wherein a mast is attached to the central beam.

8. A craft as claimed in any one of the preceding claims wherein struts or cables are used to bracing the craft for structural rigidity.

9. A craft as claimed in any one of the preceding claims wherein a body is rigidly attached to the central beam providing a central hull.

10. A craft as claimed in any one of the preceding claims wherein a rudder and tiller are attached to any one of the hulls.

11. A craft as claimed in any one of the preceding claims wherein a trampoline is provided as a deck to accommodate the crew.

12. A craft as claimed in any one of the preceding claims wherein the two outriggers are asymmetrically cambered.

13. A craft substantially as described herein with reference to Figure 1 and Figure 2 of the accompanying drawing.