GB2306406A

GB2306406A - Expanding open bridge-deck catamaran

Info

Publication number: GB2306406A
Application number: GB9522337A
Authority: GB
Inventors: Derek Hammersley Kelsall
Original assignee: Individual
Current assignee: Individual
Priority date: 1995-11-01
Filing date: 1995-11-01
Publication date: 1997-05-07
Also published as: GB9522337D0

Abstract

A catamaran has telescoping cross beam assemblies extending between its hulls 10 in order to give wide overall width in normal operation on the water and reduced width for storage and transport. Each beam assembly consists of five beam parts, namely a central beam 11, the length of which is close to the width of the catamaran in narrow condition, two sleeve beam parts 12 which slide over the central beam part and two hull beam parts 13 which are fixed in or onto each hull 10. In narrow width condition, Fig 4, the central beam part 11 and the sleeve beam parts are housed wholly or partly within the hull beam parts.

Description

EXPANDING OPEN BRIDGE-DECK CATAMAR4.

This patent relates to an open bridge-ck catamaran, where the wide overall width while operating on water is reduced for transport or storage.

Catamarans that are demounted for transport are u-ell known craft that consist of to hulls and connecting cross beams. The cross beams are usually attached to the hulls by straps, through-bolts or tapered sockets. The time taken, the handling of all the parts and the space required to assemble and disassemble is a considerable inconvenience. More elaborate and expensive hinged or folding beam systems are also knon It is an aim of the present invention to provide an expanding catamaran, that is simple to construct and operate, that expands and contracts on the water, for storage on water in the narrow condition, as well as for launching and retrieving from the water in the narrow condition.

According to the present invention, there is provided a catamaran comprising two hulls and two or more cross beam assemblies, there each cross beam assembly consists of five telescoping beam parts. a main or central beam part, two sleeve beam parts and two hull beam parts.The central beam part, which approximately spans the distance between the hulls in normal wide condition, being the smallest in cross section, slides within the intermediate sleeve beam parts, which are approximatels the width of the hulls and which themselves slide within the hull beam parts, utich are fixed in or on the hulls, allowing the width of the catamaran to be reduced from the normal wide operating width, to the approximate width of the two hulls only, side by side, with the central beam part and the sleeve parts housed wholly or partly within the hull beam parts.

The beam parts may be round, oval, rectangular or other outline section shape.

The beam parts may include recesses, on one or more of the beam faces for the purpose of fitting tracks, or to use wedges or other means of reducing the clearance between beam parts in order to eliminate movement between parts.

The craft may include means of moving the beam parts using winches or tackles, which may operate within the beams.

Alternatively the craft may be such that the hulls and beam parts can be manually pushed into their required positions.

The sliding beam parts may include flanges at the ends, which will be either inward or outward flanges depending on the relative position of the respective overlapping beam part, to improve torsional stiffness and resistance to bursting pressure and to provide attachment for deck or other items.

The craft may include hinged deck panels between the hulls and the beam assemblies, where the deck panels provide the means of locating the hulls and the beam parts relative to each other when the craft is in the wide condition.

Alternatively, the decking may be of flexible material such as sail cloth, which is attached to the hulls and to the beams such that fixings to the decking material locate the beam parts when the craft is in the wide condition. With flexible decking, another form of fixing, such as bolts through the beam parts or poles that fix into the assemblies will be used to retain the hulls at the wide spacing. Such poles may be used, along with tackles or lines to move the beam apart.

A specific embodiment of the invention will now be described by way of example with reference to the accompanying drawing in which : Fig. 1. shows in perspective, the catamaran in its wide sailing condition.

Fig. 2. shows the catamaran in its reduced width condition for transport or stowage.

Fig. 3. shows a section through one of the cross beam assemblies in the wide arrangement.

Fig. 4. shows a section through one of the cross beam assemblies at reduced width.

Fig. 5. shows a section through one of the cross beam assemblies, where the central beam part is longer than the width of the two hulls side by side and can be retracted from the hull for transport.

Referring to the drawing, the catamaran consists of hulls 10, central beam parts 11, intermediate sleeve parts 12 and the hull sleeve parts 13 fixed in the hulls. The intermediate sleeve beam part is a sliding fit within the hull beam part which is fixed in the hull and the central beam part is a sliding fit within the sleeve beam part.

In order to reduce the width, the hulls move together by telescoping the beam parts till both the central beam part and the sleeve parts are housed wholly or partly within the hull beam parts. in normal operation this will be done while afloat. At reduced width, one sleeve part and approximately halfofthe central beam part are contained within each hull beam part, which is fixed wholly or partly within the hull. The overlapping of the beam parts and the sliding fit between them provides the cross connection between hulls. The length of each sleeve beam part is similar to the width of one hull approximately and approximately half of the length of the central beam part. The arrangement shown allows for approximate doubling of the width of the catamaran between narrow and wide condition.

In order to accommodate catamaran designs that require rider sailing width, the central beam parts, and possibly the sleeve parts. can he of greater length and will protrude through the out-board side of one or of both hulls z hen in the reduced width condition. The central beam parts and possibly the sleeve beam paris can then be removed for transport, by sliding them from the hull. chile the hulls are supported on the trailer or other transport.

Claims

CLAIMS.

1. An open bridge-deck catamaran where the width is expanded and reduced using telescoping beam parts, the central beam part being the smallest in section to slide within sleeve parts, which sleeve parts slide within a similar but larger section that is fixed wholly or partly within or on the hulls

2. An expanding catamaran as in 1. where decking between the hulls is hinged to provide the width fixing in the wide configuration.

3. An expanding catamaran as in 1. or 2. where the overall width when expanded is substantially greater than the width of the two hulls together and one or more of the sleeve parts or the central beam part are removed, by sliding outwards through the hull beam part to achieve minimum width for transport or storage.

4. An expanding catamaran as in 1. or 2. where the central beam part and the hull beam parts have recesses on one face into which a wedge system is arranged to reduce the clearance between the sliding parts in order to stop movement between them.