GB2385575A

GB2385575A - Stabilising a sailing vessel with inverted hydrofoils

Info

Publication number: GB2385575A
Application number: GB0204416A
Authority: GB
Inventors: Victoria Orr
Original assignee: Individual
Current assignee: Individual
Priority date: 2002-02-26
Filing date: 2002-02-26
Publication date: 2003-08-27
Also published as: GB0204416D0

Abstract

A sailing vessel has at least two symmetrical outrigger arms 1A and 1B, mounted on hinges 5 one on each side of the vessels centre line and in transverse alignment at midships. Each of the outrigger arms has an inverted hydrofoil 8A and 8B suspended from the end that extends out from the vessel. In use each of the hydrofoils is movable between a deployed position where the hydrofoil is fully submerged when its outrigger arm is on the windward side of the vessel and a stowed position where the hydrofoil is withdrawn to a position above the surface of the water when its outrigger arm is on the leeward side of the vessel.

Description

Means to reduce heeling in sailing vessels.

In a sailing vessel the use of fully submerged inverted hydrofoils suspended from the windward side for the purpose of reducing the angle of heel to leeward caused by the effect of wind uponhe sails is infrequently practiced. The handling of such devices in conditions in which they would be most ben & fioal is difficult. Namely strong winds and rough seas. These conditions cause the sailing vessel to be an unsteady platform.

It is the intention that crew safety is of paramount importance.

Ease of use and speed of operation are important aims, as confusion at a critical time could jeopardize the vessels safety. It is expected that this invention will minimise the free movement of any piece of equipment necessary for the deployment of the inverted hydrofoils and their recovery.

In a forwardly moving sailing vessel of symmetrical form in which at least two outriggers one on each side of the vessels center line in transverse alignment at about the vessels midships from which windward outrigger is suspended a fully submerged inverted hydrofoil, at its most outboard part, attatched to both outriggers is a robust and secure stowage for the inverted said hydrofoil when not in use, and that when said windward hydrofoil is in operation the leeward inverted hydrofoil is stowed on the leeward outrigger ready for use at a height above the water surface and that both said outriggers are attatched to the vessel by a hinge at or near deck level, such that the leeward outrigger can be inclined

upwardly outward relative to the transverse deck line whilst the windward outrigger be inclined downwardly outward relative to the transverse deck line to be generally horizontal, and that by operational requirement the configuration be reversed with the leeward side becoming the windward side respectively, caused by a change in the vessels direction as in tacking.

The use of an outrigger on tha windward side improves the mechanical advantage of the system, its leeward counter-part in raising the stowed said hydrofoil clear above the water surface.

The increased transverse stability is achieved with only a small increase in overall weight, a drag that is proportional to the down-thrust, and 8 increased ability to carry sail area leading to the potential higher speeds for planing vessels.

Fig. is a view in cross section at approximately midships of a mono-hull sailing vessel having a keel and ballast bulb in which the outriggers are hinged to the deck edge.

Fig. 2. is a view in cross section at approximately midships of a mono-hull sailing vessel having a keel and ballast bulb in which outriggers are hinged inward of the deck edge towards the vessels center line.

Fig. 3 is a plan view of a trimaran in which two windward and two leeward outriggers are arranged in transverse alignment.

The outriggers for the central hull are of the simple beam or pole type, whilst those on the outer hulls may bo be ?, m or'A'frame configuration with said hinges one on each leg.

Fig. 4 is a view in cross section of the trimaran shown in Fig.

Refering to Fig. 4 wherein the inverted hydrofoil rut C is suspended from the outermost part of an outrigger/, *,/c

located on the windward side of the vessel near to midships by a, flexible wire rope : that passes over a pulley at the outboard end of the outrigger and then aboard the vessel for controll. At the outer part of each outrigger the said pulley may be part of a secure stowage mechanism , that is attatched to or integral with the outrigger. The stowage mechanism must be easy to operate, with locking means to secure the said hydrofoil in stowage together with an easy to operate release mechanism for launching said hydrofoil. Means to'operate these from aboard the vessel. The cycle from operation through stowage to operation must not require disconnecting or reconnection of any part that would affect the correct operation of the hydrofoil.

The outriggers are robustly constructed. At the inboard end of each outrigger is ane or more hinge 5, where in board of the dec edge the hinge will require lifting on a suitable robust part of the vessel, to allow for the declination below the deck line of the windward outrigger. The hinge g allows the outer end of each

outrigger to pivot up and down in the athwartships plane relative to the deck line in that plane, when upright or heeled. A stay or strong halyard 6 connects the outer end of the outrigger to an elevated position on the mast, thereby transferring the downforce on the outrigger to the mast 7. This stay / halyard is adjustable to alter the inclination of the outer end of the outrigger. In operation it is desireable that the windward outrigger is generally horizontal and relative the transverse deck line inclined downwerdly outward. The leewara outrigger has a different function. Its purpose is to lift the securely stowed leeward gaz inverted hydrofoil clear of unintended contact with the water.

This leeward outrigger is raised upwardly outward by the stay/ halyard relative the transverse deck line. It should be noticed that with using outriggers with their hinge near to the vessels center line the upward lift of the outer end of the outrigger is greater. Additionaly it is necessary to restrain the leeward outrigger from lifting, this preventer,'1 extending from the deck to the outer part of the outrigger, alternatively on the deck edge hinge location a compression preventer extending from the outrigger to the mast or deck indicated by/0. Additional stays extending fore and aft from the outboard part of the outrigger to the vessel may be necessary to prevent excessive unwanted movement.

\th a system of heel controll that could fail due to catastrophic loss in the down thrust of the inverted hydrofoil, a back-up system should be available. In Fig. 1,82 such a system is provided by the ballast keel. In Fig'-an embodiment of the invention that provides an additional outrigger on each side of the vessel, such that all outriggers are in transverse alignment.

The extra outriggers to be equiped with inverted hydrofoils and the dunlicate controlls.

The drag produced by the said hydrofoil at a distance outward of the vessels center line will create a torque resulting in weather helm. Another embodiment of the invention that will minimise this undesirable feature is by the placing of two extra outriggers and their inverted hydrofoils snaced apart longitudinally about the vessels midships, with each pair of outriggers in transverse alignment.

In another embodiment the inboard hinge of each outrigger is

located on the vessels center line with each outrigger pivoting jW about theApoint. With the two outriggers at their inboard ends A locked together by a suitable means to present one athwartships beam / pole comprising two parts pivoting about a common axis.

Claims

CLAIMS.

Claim I.

In a forwardly moving sailing vessel of symmetrical form in which at last two BYmifetric, outriggers, one on each side of the said vessels center line are located in transverse alignment at about the vessels midship) from said outrigger on the windward side of the vessel at its most outboard part is suspended a fully submerged and inverted hydrofoil, attatched to both said outriggers is a. robust and secure stowage for the said hydrofoil when not in use, and that when said windward hydrofoil is in use a second inverted hydrofoil connected and ready for use is stowed securly on the leeward said outrigger at a height above the water surface, and that both said outriggers are attatched to the vessel by a robust hinge at their respective inboard ends at or near deck level, and that at least the said windward outrigger be generally horizontal athwartships, and that by operational requirement the configuration of windward and leeward be reversed as required.
Claim 2.

A vessel as claimed in Claim I in which the hinge of each outrigger be attatched to the deck at the vessels outer sides.

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Claim 3.

A vessel as claimed in Claim I in which the hinge is located inward from the vessels outer deck edge nearer to the vessels center line and attatched to a structure of the vessel slightly above deck level.
Claim 4.

A vessel as claimed in Claim I Claim 2 and Claim 3, where-in the outriggers are detatchable.
Claim 5.

A vessel as claimed in Claim I through to Claim 4 of trimaran shape in which an additional outrigger and additional inverted hydrofoil be employed on each side of the vessel such that all outriggers are in transverse alignment.
Claim 6.

A vessel as claimed in Claim I through to Claim 4 of trimaran shape in which an additional outrigger and additional inverted hydrofoil be employed on each side of the vessel such that they are longitudinally spaced apart either side of the vessels midships.
Claim 7.

A vessel as claimed in Claim I and Claim 4, where two outriggers have hinges that have a shared common pivot, located,. on the vessels center line.

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Claim 8.

A vessel as claimed in Claim I, Claim 4 and Claim 7, where the two outriggers are operating as one continuous beam/pole comprising two parts secured together.
Claim 9.

A sailing vessel with outriggers and inverted hydrofoil in use only on the windward side of the vessel substantially as herein described and illustrated in the accompanying drawings.