EP0094944A4

EP0094944A4 - Steering vessels.

Info

Publication number: EP0094944A4
Application number: EP19820903298
Authority: EP
Inventors: Donald George Daw
Original assignee: Individual
Current assignee: Individual
Priority date: 1981-11-30
Filing date: 1982-11-19
Publication date: 1985-02-28
Also published as: EP0094944A1; IT8268392A0; WO1983001934A1; JPS58501989A

Abstract

A vessel having at least one hull (1) with a keel (2) intermediate the bow (4) and stern, having its rudder (5) or rudders adjacent to bow (4) forward of and spaced from the keel (2), with or without a vane or rudder at the stern.

Description

"STEERING VESSELS"

This invention relates to means for steering vessels and in particular it relates to the steering of vessels of the sail driven type but the invention is not necessarily limited thereto.

Many attempts have been made to provide improved steering means for vessels, particularly sailing vessels where drag requires to be minimal, yet effective steering is required irrespective of the angle of the hull of the 0 vessel in relation to a horizontal position, and this invention is dire'cted to the type of hull which has a keel at a generally medial part of the hull and normally has a rudder at the rear of the hull.

It is known from USA Specification No. 65,093, F.W. 5 Kuhnert, dated May 28, 1867 to have a full-length keel with a normal rudder at the rear end and with a series of auxiliary rudders arranged one after another in openings in the keel.

USA Specification No. 956,404, S.B. McNeely dated o April 26, 1910 shows a forward rudder, normally retracted during forward motion but moved down when the vessel is " travelling backward to then form rear steering means.

USA Specification No. 1,888,443, G.A. Alexander, dated November 22, 1932 has a rudder at each end of a propulsion tube extending along the underside of the hull so that both rudders are in water forced through the tube.

USA Specification No. 1,968,577, G.R. Taylor, dated July 31, 1934 shows a front rudder on a towed barge, the barge having a flat bottom, so that the front of the

OMPI barge can be controlled during towing from a bank to urge the barge away from the bank.

USA Specification No. 3,990,384, C.J. Reynolds dated November 9, 1976 shows a rudder forming part of the rear of a keel, but the purpose is said to be to control heeling.

In hyrdofoil ships it is known to use forward steering by turning a forward hydrofoil, see USA Specification No. 3,999,496, of P.M. Mirande, dated December 28, 1976 but in these the vessel is raised above the water, and no keel is involved.

None of the above vessels however relate to vessels, particularly sailing vessels, of the type having a keel at or adjacent the medial part of the hull and normally steered by a rudder at the rear of the hull.

One of the problems with vessels, particularly sailing vessels, is to achieve effective control of direction with a minimum of water drag, and with the conventional type of control where a rudder is positioned at the rear of the vessel, generally in line with but to the rear of the keel, the rudder operates in disturbed water due to movement of the hull and keel through the water ahead of the rudder.

This renders the rudder less effective and therefore increases the drag because of the displacement required of the rudder to achieve effective steering.- One of the objects of the present invention is to reduce rudder drag as it exists with the assemblies used at the present time. Being more efficient the surface area of the rudder blade can be reduced.

- JRE_£7 OMPI Another problem with the steering of vessels is that the water flow may be at an angle to the medial line of the keel and this results in a relatively smooth flow on one side of the keel but on the other side of the keel the flow is displaced outwardly and then inwards to hit the rudder angularly to spoil effective rudder control and, because of flow variation, making constant correction necessary. A further object thus is to lessen steering difficulties due to inequality of flow around the keel which may occur under various conditions.

According to my invention, the rudder instead of being placed at the rear of the vessel is moved forwardly to a position where it operates in relatively undisturbed water, and thus the rudder is placed forward of the keel and preferably in line therewith unless multiple forward rudders are used, so that water flow is first over the surfaces of the rudder and then over the keel.

By angling the rudder in relation to the plane of the keel, highly effective steering of the vessel results.

Having the rudder placed forward of the keel increases the manoeuvrability of the vessel, including the ability of the vessel to tack through the wind.

Such a vessel can be constructed much as hereto¬ fore but with a forward rudder or rudders, and it will be realised that for instance in racing yachts the use of a forward rudder or rudders with a trailing keel will give substantially less drag than at the present time by maintaining a better water flow along the keel.

OM

^ Such a vessel comprises a hull having a depending keel intermediate the bow and stern characterised by rudder means forward of the central part of the keel.

It is of course possible according to my invention to use a compound arrangement in which both a forward and perhaps a smaller rear rudder are used, and it will be appreciated that the rudder need not necessarily be in line with the keel nor is the invention limited to a single forward rudder because it may sometimes be advantageous to use perhaps two rudders spaced outwardly somewhat from the centre line of the vessel and projecting into the generally undisturbed water at the forward part of the vessel.

In order that the invention may be more clearly understood an embodiment thereof will now be described with reference to the accompanying drawings which are in the nature of illustrations only and not to be taken as necessarily limiting the invention.

In the drawings:

FIG. 1 is a side elevation of a yacht showing the invention applied by use of a rudder forward of the keel,

FIG. 2 is a plan view of the outline of the hull of the yacht to show the position of the rudder and the keel,

FIG. 3 shows how the rudder can be angled or raked in relation to the vertical to give different lift and steering effects, the dotted lines indicating opposite angling of the rudder. A vertical rudder could be used but with means to angle it to either position.

( OMP FIG. 4 is a side elevation showing a forward and a rear rudder which could be oppositely steered or independently operated.

FIG. 5 is a plan view of FIG. 4 showing the forward and rear rudder in relation to the keel,

FIGS. 6 and 7 show in side elevation and plan how forward twin rudders can be arranged, these figures showing also a rear rudder which can be steered oppositely to the forward rudder to assist turning the vessel about the.keel or it can be used as a stabiliser or can be omitted.

FIGS.. 8 and 9 show the invention applied to a catamaran.

In the following description similar components excepting for the rudders are similarly numbered.

Referring first to FIGS. 1 and 2, the hull 1 of the vessel has the usual keel 2 and mast 3 together with its rigging, and has near the bow 4 a rudder 5 projecting downwardly from a stem 6 to which steering torque is applied.

The rudder is positioned forwardly of the keel 2 to be in relatively undisturbed water and in that position gives a steering effect with the keel 2 acting as a stabiliser about which the steering is generally effected.

In the form shown in FIG. 3 the rudder 7 is shown as being displaced from a vertical position to a rearwardly sloping position, or it may be forwardly angled as shown in the dotted lines at 8, the angle of the rudder being either permanent or adjustable between the two positions shown. The steering stem 9 of the rudder may be at the same angle as the rudder or may be normal to the longitudinal centre line of the vessel, the steering stem 9 being journaled in bearings in the hull in any conventional manner.

It will be realised that by selecting the angle of the rudder either permanently or in the nature of a variable control, the positive or negative lift effect of the rudder as the vessel heels can be selected, thus aiding in the steering control.

In the form of the device shown in FIGS. 4 and 5 the rudder 11 is forward of the keel 2 and is rotatable about the axis of a steering stem 12 journaled in bearings in the hull so that the the rudder can be angled, but in this embodiment a rear rudder 13 is used and these two rudders 11 and 13 can be angled oppositely to both give a turning moment about the keel 2,

The two rudders 11 and 13 can be interconnected for simultaneous opposite movement but need not necessarily move in the same ratio or be of similar dimensions, and generally the rudders can be smaller because of the compound steering action.

While in the foregoing embodiments a single forward rudder control has been described it would be possible as shown in for instance FIGS. 6 and 7 to use a pair of rudders 14 and 15 positioned one each side of the centre line 16 which passes through the keel 2, these rudders 14 and 15 taking the form of the rudder 5 described in relation to FIGS. 1 and 2, and if necessary angled

OM permanently or variably as referred to in FIG. 3.

In this figure also a rear rudder 17 is shown in dotted lines this rear rudder 17 allowing further control of steering about the keel 2 by opposite angling of the forward and rear rudders respectively, or the rear rudder 17 may be a fixed or variable angle vane for the purposes of stabilisation.

In FIGS. 8 and 9 is shown how the invention can be applied to a catamaran, the two hulls 20 and 21 being joined by a platform 22 as usual which can extend longitudinally any required distance. A pair of centre-boards 23 and 24 form keels and steering' is by forward rudders 25 and 26 rotationally supported from a strut 27 joining the two hulls 20 and 21.

The rudders 25 and 26 could project downwardly directly from the hulls 20 and 21 but are preferably mounted as shown to allow them to fold back in shallow water as is usual in catamarans. The centre-boards 23 and 24 can be drawn upwards in shallow water.

Assisting rear rudders, not shown could also be used in the manner described with reference to FIGS. 4 and 5 or 6 and 7.

From the foregoing it will be realised that instead of the vessel simply having a keel and a rudder placed to the rear of the keel with a substantial distance between them, steering can be effected by a forward rudder or rudder assembly with or without the assistance of a rear vane or rudder where this is found desirable.

^•<BTJR!

OMPI ^ IPO

Claims

AMENDED CLAIMS

[received by the International Bureau on 21 March 1983 (21.03.83); original claims 1 to 15 have been replaced by amended claims 1 to 15; the text of the amended claims follows]

1. A sailing vessel having a hull and at least a mast upwardly projecting therefrom, a keel downwardly projecting therefrom intermediate the bow and the stern of the said hull, characterised by rudder means 'on the said vessel forward of and remote from the said keel, and means to move the said rudder to steer the said vessel.

2. A sailing vessel according to claim 1 character ised in that the said rudder means are positioned at the bow part of the said vessel remote from the said kee which is disposed at the medial part of the said hull.

3. A sailing vessel according to claim 1 character¬ ised in that the said rudder means comprise at least a pair of rudders positioned one on each side of the longitudinal centre line of the hull on which the said keel is positioned._.

4. A sailing vessel according to claim 1 character¬ ised in that the said rudder means comprise at least one rudder positioned to move about the axis of a steering stem, said rudder projecting downward substantially normal to the longitudinal centre line of the said vessel.

5. A sailing vessel according to claim 1 character¬ ised in that the said rudder means comprise at least one rudder positioned to move about the axis of a steering stem, said rudder projecting at an angle to have its lower part trail in relation to an axis normal to the longitudinal centre line of the said vessel. 6. A sailing vessel according to claim 1 character¬ ised in that the said rudder means comprise at least one rudder positioned to move about the axis of a steering stem, said rudder projecting at an angle to have its lower part advanced in relation to an axis normal to the longitudinal centre line of the said vessel.

7. A sailing vessel according to claim 1 character¬ ised in that the said rudder means comprise at least one rudder positioned to move about the axis of a steering stem said rudder projecting downward but variable in angle in the plane of the keel from a position where its lower part projects forwardly or trails in relation to an axis normal to the longi¬ tudinal centre line of the said vessel.

8. A sailing vessel according to claim 4, 5, 6 or 7 wherein the said stem is at the same angle as the said rudder.

9. A sailing vessel according to claim 1 or 3 characterised by a vane rearward of the said keel and remote from the said keel.

10. A sailing vessel according to claim 1 or 3 characterised by a rudder rearward of the said keel and remote from the said keel, and by means to move the said rudders oppositely.

11. A sailing vessel according to claim 1 or 3 characterised by a rudder rearward of the said keel and remote from the said keel, and by means to move the said rudders independently.

OϊvϊPI ^l ^K'> WIFO 12. A sailing vessel according to claim 1 wherein a pair of hulls are used, said hulls being spaced apart a fixed distance, each said hull having a keel intermediat the bow and stern, and each said hull having a rudder spaced from and forward of the said keel, and means to interconnect said rudders to steer similarly.

13. A sailing vessel according to claim 12 wherein the said rudders and the said keels are movable to retract them from a downward operative position.

14. A sailing vessel according to claim 12 wherein the said rudders are mounted on a strut joining the said hulls at their forward end portions, said rudders being positioned adjacent to the said hulls.

15. A sailing vessel comprising at least a hull having a dependent keel intermediate the bow and the stern, characterised by rudder means spaced from and forward of the said keel.