AU588632B2

AU588632B2 - Trimarans with adjustable outriggers

Info

Publication number: AU588632B2
Application number: AU63386/86A
Authority: AU
Inventors: Bruce Arthur Wallach
Original assignee: Individual
Current assignee: Individual
Priority date: 1985-09-16
Filing date: 1986-09-10
Publication date: 1989-09-21
Anticipated expiration: 2006-09-10
Also published as: AU6338686A; WO1987001671A1; EP0236364A1

Description

TRIMARANS WITH ADJUSTABLE OUTRIGGERS

The present invention relates to multi-hull sailing vessels and more particularly to a trimaran in which means are provided to permit the adjustment and securement in position of the outer hulls whilst allowing the width of the vessel to be reduced for ease of transport and storage.

Trimaran sailing vessels are a well known class of craft that are able to achieve performance comparable to other sailing craft such as catamarans and skiffs. In considering performance, it will be appreciated that one of the factors which determines the performance of a sailing vessel is, all other factors being equal, the extent of the wetted surface of the hull.

For a craft that is single hulled, the wetted surface may be reduced to an optimum by causing the craft to heel under applied wind load and/or positioning of the crew. In the case of a catamaran, the wetted surface may be ' reduced by causing one hull to be clear of the water again under applied wind load and/or positioning of the crew. However, in the case of a trimaran, in minimizing the wetted surface it would be necessary to balance the craft in a manner such that both outer hulls were out of the water. Clearly, to achieve this balance, the positioning of the crew in relation to the magnitude of the applied wind load is important. A further consideration is the height of the outer hulls aoove the water, which if the outer hulls were fixed in position, would depend on the weight of the crew.

Additionally, in those situations where craft performance is not paramount, in order to achieve a greater degree of comfort in sailing, it may be desirable to ensure that the outer hulls remain substantially in contact with the water whilst sailing.

The present inventor has recognized that there exists a need for a trimaran craft where adjustment of the height above the water of the outer hulls may be made in order to optimize the height in relation to the weight of the crew and hence optimize the performance of the craft.

In regard to the overall dimensions of a trimaran, particularly in the case of small craft, the overall width of such craft make them difficult to transport and store. The present inventor has recognized that in order to minimize this difficulty it would be advantageous to provide a craft in which the deck and outer hulls could be readily removed from a craft, but when in place for sailing, would ensure that the craft was structurally sound.

Accordingly, it is an object of the present invention to provide a trimaran capable of being reduced in width for ease of transport and storage, having outer hulls which are capable of being « adjusted in height, whilst retaining satisfactory sailing performance.

In the prior art, there are known a number of alternative trimaran designs that allow the craft to be reduced in width. An example of such a craft is disclosed in U.S. 4,172,426 (Susman) . In this patent, through the use of wire braces and a pair of arms that pivot both on the outer hull and the intermediate hull, an outer hull may be folded inwards towards the intermediate hull to reduce the craft ' s width. When ready for sailing, an outer hull is folded outwardly and the wire braces are appropr iately tensioned to hold the outer hull spaced apart from the intermediate hull . It is to be noted, however , that there is no provision for the adjustment of the height of the outer hulls above the water.

Further examples of the art disclosing trimarans in which the craft may be reduced in width are U.S. 3,954,077 (Piat-Marchand) and U.S. 3,996,874 (Winch). However, neither of these patents discloses adjustment of the outer height of the hulls above the water. The present invention consists in a trimaran sailing vessel comprising a pair of substantially parallel outer hulls, each of which is connected through an arm by an attachment means to an intermediate hull, which hull supports the mast, said attachment means being affixed to a supporting member which is located on said intermediate hull, the attachment means allowing the arms to pivot in a manner that permits the height above the water of an outer hull to be adjusted, and brace means extending from each outer hull towards the bow and stern of the vessel such that the movement of the arms is substantially restricted.

The advantage of the present invention lies in the provision of a trimaran which can be reduced in width, to facilitate transport and storage whilst having a means to permit the performance in terms of the immersion of the outer hulls to be optimized. Further, when disassembled, in a typical embodiment, the heaviest element is no more than 20kg, thereby permitting a vessel of the invention to be readily transported on the roof racks of a car. The present inventor also believes that the cost of manufacturing the trimarans of this invention is competitive to that of other craft of similar performance.

Additionally, the present invention may be readily distinguished over the prior art in particular by its use of the connection of the arms to a support member on the intermediate hull in a manner such as to permit the height of the arms above the water to be adjusted.

The arms may be connected to any point on the outer hulls. However, in order to produce the best performance of a vessel the arms preferably connect to an upper portion of the hulls in a manner that will minimise the occurrence of immersion of the arms when sailing.

In a preferred embodiment, the arms curve upwardly away from where they connect to the outer hulls, to form a straight portion which connects by the attachment means to the intermediate hull. It will be appreciated, however, that other arm designs or configurations can be used to achieve the desired performance.

The arms may be formed from any suitable material having requisite strength and durability.

The point of connection of the arms to the outer hulls is preferably substantially centrally longitudinally located, though in some instances it may be desirable to alter this position depending on other design requirements. In the central position, the overall strength and performance of the vessel would be optimised.

The connection of the arms to the intermediate hull is by an attachment means. It will be appreciated that such a means could be located anywhere on the intermediate hull, provided that it is of sufficient height to ensure optimum height adjustment of the outer hulls.

Preferably, the attachment means is located on the mast at an appropriate height to ensure that the height of the outer hulls above the water can be readily adjusted. In this embodiment, the mast serves as a supporting member. Though it will be realized by persons skilled in the art that for example a short mast-like structure located forward of the mast could constitute a support member. In one embodiment in which the attachment means is mounted on the mast and where it is desired that the mast be rotatable, clearly the attachment cannot be directly affixed to the mast. Rather, a sleeve having an inner diameter selected to accept the mast is used with the attachment means being affixed to the sleeve and the sleeve may be held at its lower end to the intermediate hull.

In such an embodiment it is preferred that each of the attachment means are located on opposing sides of the mast. Naturally, in order to ensure maximum performance the position of the attachment means on the mast with respect to height above the intermediate hull will be substantially the same.

The determination of the height of the attachment means will depend on a number of factors, such as shape and configuration of the arms, dimension of the hulls etc. Preferably, the height of the attachment means will be such that when the vessel is sailed by a crew of average weight, the outer hulls will not contact the water when the vessel is balanced in still air.

In order to optimise the performance of a vessel, the attachment means permits the arms to pivot. The pivot action at least allows an outer hull to be positioned substantially parallel to the intermediate hull and also with respect to its height above the water. However, it is preferred that the attachment means comprises essentially a means for forming a universal joint connection between an arm end and the intermediate hull. In this embodiment, the fore and aft position of the outer hulls may also be varied, whilst retaining all of the hulls in parallel array.

In the particularly preferred embodiment, where the arms connect to the mast, a gooseneck type connector may be used. Such a connector is fixed in position on the mast and forms a universal connection with an arm which allows an arm to be readily detached.

Brace means are used to restrict the movement of the arms which consequently also restrict the movement of the outer hulls since they are connected to the one end of the arms. Preferably the brace means comprise a plurality of stays which are positioned suitably between the intermediate hull and the point at which the arms join the outer hull and between an upper position on the mast and the point at which the arms join the outer hull. These latter stays also serve to assist in the securement of the mast.

In a particularly preferred embodiment, a pair of stays extend from a point adjacent to the bows of the intermediate hull to a point where an arm joins an outer hull and a point lying nearer to the point of attachment of an arm to the intermediate hull.

In the embodiment where the attachment means is a universal joint, the length of the appropriate stays may be varied depending on the position fore and aft that the outer hulls occupy.

The brace means that extend from the outer hulls to the stern are preferably constituted by a pair of web members, each web member being connected at one end to an arm and at an opposing end to the stern. By appropriately dimensioning the web members, together they constitute a deck.

The web members so connected are preferably tensioned and connected to the hulls by a suitable means. The outer edge of the webs will preferably taper inwardly towards the intermediate hull whilst the inner edge will preferably be in substantial alignment with the outer edge of the intermediate hull. Thus the web members will be substantially triangular in shape when suitably tensioned. In this configuration, the web members may provide a suitable platform from which the crew may sail the craft.

A suitable means for tensioning the webs may be by way of a wire, one end of which connects to the web and the other to a highfield lever. By suitably pre-adjusting the length of the wire, a substantially reproducible tensioning force may be applied to the web. It will be appreciated that the tension applied to each web should be substantially the same in order to ensure the efficient sailing of the vessel. The webs may be conveniently formed of any suitable material providing that it is sufficiently resilient to permit the required tensioning.

In use, the length of the stays would be predetermined and adjusted in a manner such that when the outer hulls were attached to the intermediate hull, together with the stays and the webs placed under tension, the resultant positions of the outer hulls would be optimal with respect to their height above the water when sailing. Hereinafter by way of example only is preferred embodiment of the present invention in which:-

Fig. 1 is a side elevational view of a trimaran of the present invention;

Fig. 2 is a plan view of a trimaran of the present invention, and

Fig. 3 is a front end elevational view of a trimaran of the present invention.

The trimaran 10 comprises an intermediate hull 11 and two outer hulls 12. The outer hulls 12 are connected to a mast 13 located on the intermediate hull 11 by a pair of arms 14. The hull 11 is formed from synthetic plastics material reinforced with glass fibres, whilst the outer hulls and arms are formed of a suitable gauge of aluminium. An attachment means comprising a gooseneck 24 connects one end of each of the arms 14 to the mast. The other end of the arms are each formed to curve downwardly to connect to an outer hull 12.

Brace means comprising a pair of stays 15, 16 are provided to restrict the movement of the arms 14 to a horizontal plane in a direction towards the bow 17 of the trimaran. This is accomplished by positioning the stays 15 to connect at one end to a point adjacent the bows and at the other end to a point on the arms lying towards the point where an arm connects to an outer hull 12. Stays 16 are similarly connected adjacent the bows at one end and at the other end to an arm at the point at which it joins an outer hull.

Stays 25 are similarly connected to stays 15 at one end to the arms and at the other end to a point on the intermediate hull 11 lying midway along and on the side of the hull.

In conjunction with the stays 18, which extend from the mast to the outer hulls, the brace means is able to restrict movement to one in which the arms may only move in a plane parallel to the longitudinal axis and in a direction towards the bow of the trimaran.

The stays are formed of steel wires, though any other materials having the requisite strength could be used. In order to maintain the outer hulls substantially parallel with the intermediate hull, a pair of braces 20 is provided for each outer hull. Each brace 20 is connected at one end to a point on the arms wher"e a stay 15 is similarly connected and at the other end to the upper surface of the outer hull, such that the point of connection for each brace on the outer hull is equally spaced apart from where an arm connects to an outer hull.

A pair of web members 19 are each connected to an arm 14 in a manner such that each web extends along the length of an arm from a point at which a pair of stays 20 meet an arm, to a point immediately above the outer edge of the upper surface of the intermediate hull 11. The webs extend towards the stern 21 of the trimaran terminating at a point immediately adjacent the stern where they are each connected via a link 22 to a lever assembly 23 that permits the web to be tensioned and the arms to be moved in a horizontal plane towards the stern. The webs are formed from a suitable grade of dacron. When the webs are suitably tensioned they form a trampoline from which the crew are able to sail the trimaran.

Claims

CLAIMS : -

1. A trimaran sailing vessel comprising a pair of substantially parallel outer hulls, each of which is connected through an arm by an attachment means to an intermediate hull, which hull supports the mast, said attachment means being affixed to a supporting member which is located on said intermediate hull, the attachment means allowing the arms to pivot in a manner that permits the height above the water of an outer hull to be adjusted, and brace means extending from each outer hull towards the bow and stern of the vessel such that the movement of the arms is substantially restricted.

2. A trimaran as in claim 1, wherein the supporting member is constituted by the mast.

3. A trimaran as in claim 2, wherein the brace means extending to the stern constitute a pair of web members, each web member being connected at one end to an arm and at an opposing end to the stern, said webs being dimensioned to provide a deck.

4. A trimaran as in claim 1, wherein the attachment means is a universal joint.

5. A trimaran as in claim 3, wherein the arms are substantially straight for a majority of their length and then curve downwardly to connect to an outer hull.

6. A trimaran as in claim 5, wherein the brace means extending to the bow comprise a pair of stays, a first of which extends from the point at which an arm connects to an outer hull and a second extends from the point at which the arm commences to curve downwardly.

7. A trimaran as in claim 6, the brace means further comprising a third stay which extends from a point towards the upper end of the mast to the point at which an arm connects to an outer hull.

8. A trimaran as in claim 7, wherein a pair of braces one end of each being connected to and equally spaced apart on an outer hull and the other of each connecting to an arm at a point where the arm commences to curve downwardl .

9. A trimaran as in claim 3, wherein the web members are tensioned against the brace means by means of a wire connected at the opposing end and drawn into tension by means of a highfield lever.

10. A trimaran as in claim 4, wherein tne universal joint is a gooseneck.

11. A trimaran as in claim 10, wherein the outer hulls may be positioned fore or aft of the intermediate hull whilst all of the hulls remain parallel.

12. A trimaran as in claim 10, wherein a rotatable mast is provided by placing said mast in a sleeve, the goosenecks being affixed to said sleeve.