GB2209724A

GB2209724A - Rudder posts for marine vessels

Info

Publication number: GB2209724A
Application number: GB8820735A
Authority: GB
Inventors: R Lian Chye Lee
Original assignee: LEE DR LIAN CHYE
Current assignee: LEE DR LIAN CHYE
Priority date: 1987-09-16
Filing date: 1988-09-02
Publication date: 1989-05-24
Also published as: GB8721742D0; GB8820735D0; AU2211988A

Abstract

A rudder post for a marine vessel is provided with a neck zone (26) in the post (20) in which a ring (28) is located. A swivel (32) is connected between the stern (34) of the vessel and a shaft (30) connected to the ring. An arcuate member (38) is connected to the stern of the vessel, one side of which is provided with a series of serrations (40) into which the upper part of the rudder post engages. By keeping the rudder post vertical as the vessel heels over the drag produced by the rudder (24) is kept to a minimum. Servo-controlled equipment can be provided for automatically keeping the rudder post vertical at all times. <IMAGE>

Description

"IMPROVEMENTS IN RUDDER POSTS FOR MARINE VESSELS" The present invention relates to rudder posts for marine vessels. More particularly, although not exclusively it relates to rudder posts for sailing boats or yachts.

The rudder post is the post at the stern of the boat, the tiller being secured to the top thereof and the rudder itself to the bottom thereof.

All rudder posts of known constructions, whether of motor or sailing vessels, are permanently fixed in a vertical disposition. When the vessel is displaced from the vertical, by the action of the sea or the wind, the rudder and its post will naturally tilt with it.

No problem arises when the vessel is upright. To steer the vessel, the rudder is deflected, and produces a horizontal force upon the water. This force produces some retardation of the speed, which is inevitable, but both the drag and the impediment are the minimum possible: i.e. the rudder in this instance is operating at approximately 100% efficiency.

However, when the sailing boat is sailing into the wind, i.e. tacking, and the rudder is deflected to keep the boat on course, a problem does arise.

Referring now to Figures 1 and 2 of the accompanying drawings, in the known construction referred to above, a rudder post 10 is secured to the stern 12 of a sailing boat by suitable means so that its longitudinal axis always remains fixed in relation to the stern 12 of the boat. A rudder 14 is secured at the bottom of the post 10 and can be inclined with respect to the direction of movement by means of a tiller 16 secured to the top of the rudder post 10, the post being permitted to rotate within the constraint of the securing means.

When as shown in Figure 2, the sailing boat is heeled over by means of the force of the wind, the force exerted by the rudder is no longer horizontal. The rudder force CR can be resolved into two components, namely CR the horizontal component and CR the vertical component. Only the horizontal component CR is useful to effect the steering of the sailing boat. The vertical component CR actually has a detrimental effect since it greatly increases the drag of the rudder, which reduces the speed of the boat through the water.

Thus, it will be appreciated that when a sailing boat is heeled over at an angle to the horizontal, the rudder is operating at a reduced efficiency. Moreover, the greater the tilt, the less efficient the rudder becomes in steering the boat and the greater the drag it provides.

It is therefore an object of the present invention to overcome partially or wholly the above referred to disadvantages.

According to the present invention there is provided a rudder post for a marine vessel including: pivotable means for fixing the rudder post to the stern section of the vessel; and means for adjusting the inclination of the rudder post in relation to the vessel so that it may be maintained in a substantially vertical position in relation to the surface of the water as the vessel heels over.

The pivotable means may comprise a ring constrained from moving longitudinally with respect to the rudder post, and a swivel one part of which is anchored to the stern of the vessel whilst the other is secured to the ring.

The rudder post may either be provided with a neck zone of reduced diameter, or it is provided with a pair of annular flanges, the ring being constrained in either case from movement along the rudder post.

The inclination adjusting means may comprise an arcuate member fixable to the stern of the vessel, one side face of which is provided with a plurality of serrations or undulations.

The inclination of the rudder post may be adjusted automatically by means of servo-control means energized by means for detecting whether or not the rudder post is vertical, so as to maintain the rudder post in the vertical position at all times.

The present invention will now be described in greater detail by way of example with reference to the remaining figures of the accompanying drawings, wherein: Figure 3 is a diagrammatic side elevation view of one preferred form of rudder post for a marine vessel, e.g. a sailing boat; Figure 4 is a diagrammatic rear elevation view of the rudder post shown in Figure 3 looking straight at the stern of the boat; Figure 5 is a diagrammatic plan view of the rudder post shown in Figure 3; Figure 6 is a diagrammatic view illustrating the operation of the rudder post in practice in order to substantially eliminate the vertical component Cv of the rudder force; Figure 7 is a diagrammatic side view showing the application of the principle of the rudder post to larger marine vessels, either yachts or motor vessels; and Figure 8 is a diagrammatic side view showing an automatic correcting system.

It will be appreciated that for the sake of clarity of illustration the figures are not all to the same scale.

Referring first to Figures 3 to 5, a rudder post 20 has a tiller 22 secured to the top end thereof and a rudder 24 secured to the bottom thereof. The rudder post 20 is a cylindrical shaft which is provided with a neck zone 26 of slightly less diameter. A ring 28 is provided within this neck zone 26. A short shaft 30 has one end welded to this ring 28 and the other end welded to one part of a swivel 32.

The other part of the swivel 32 is secured to the stern 34 of the sailing boat by conventional means e.g. screws 36, the arrangement being such that the ring 28 can swivel about the longitudinal axis of the sailing boat. An arcuate member 38 which extends through an arc of approximately a semi-circle or just less than a semi-circle has its two ends fixed to the stern of the boat. On the arcuate side which faces the upper portion of the rudder post 20 there is provided a series of serrations 40 or undulations into which the rudder post 20 will engage.

In operation, the helmsman is able to adjust the position of the rudder post so as to keep it as nearly vertical as possible. Thus as the sailing boat heels over, e.g. to starboard, as shown in Figure 6, the helmsman can notch the rudder post 20 along the serrations 40 so as to keep the rudder post substantially vertical in relation to the surface of the water, the ring 28 pivoting about the swivel 32.

The serrations 40 may be equi-spaced from one end of the arcuate member 38 to the other, or they may be unequally spaced, e.g. there may be more at the centre zone to provide a more accurate compensation when the sailing boat is tacking in light breezes.

Instead of the rudder post 20 being provided with a neck zone 26, it may be provided with a pair of annular flanges which are fixed on either side of the ring 28.

The above described example shown in Figures 3 to 6, illustrates the application of the principle of the rudder post to a small sailing boat or dinghy. Large yachts whether sailing or motorized, may need some more sophisticated equipment as they operate their rudders by remote control through a steering wheel which may be located at some distance from the stern of the boat. Moreover, in large yachts, the rudder post is normally wholly below the surface of the water.

As diagrammatically illustrated in Figure 7, the rudder post 20 is mounted at one end of a cranked shaft 42, the other end acting as handle 44, which the helmsman can operate in order to keep the rudder 24 substantially vertical.

For automatic operation as shown in Figure 8, a servocontrol system is utilized. A double acting mercury switch 46 is mounted on the rudder post. An electric motor 48 drives a horizontal shaft 50 through suitable gearing 52, the rudder post being mounted on one end of the shaft 50.

An electric circuit (not shown) provides the necessary control to the armature winding of the motor 48, so as to cause the motor to rotate either clockwise or anti-clockwise to correct for tilt of the yacht either to port or to starboard. When the mercury switch 46 is horizontal, i.e.

the rudder post is vertical, neither pair of contacts at the respective ends of the mercury switch is closed so the electric motor is not energized. If the yacht now tilts to starboard, the mercury flows in the double contact switch to make contact between the pair of right hand contacts. This causes energization of the electric motor 48 which rotates the shaft 50 through the gearing 52 thus tilting the rudder post 20 back to the vertical with respect to the surface of the water. Once nearly vertical, the mercury flows back to the centre and breaks the electrical circuit thus deenergizing the electric motor 48.

It will be appreciated that in both Figures 7 and 8, the steering mechanism which operates the rudder itself is omitted for the sake of clarity.

For high speed motor vessels, e.g. power boats or gun boats, the above described examples can be used to keep the rudder upright when the boat makes a sharp turn at speed, the boat heeling into the turn.

With the above described constructions of rudder posts, because the rudder is kept substantially vertical with respect to the surface of the water, the vertical component Cv is kept to a minimum thus reducing drag, whilst the horizontal component q is kept to a maximum thus increasing the efficiency of the rudder under all wind and weather conditions.

Claims

CLAIMS:

1. A rudder post for a marine vessel including: pivotable means for fixing the rudder post to the stern section of the vessel; and means for adjusting the inclination of the rudder post in relation to the vessel so that it may be maintained in a substantially vertical position in relation to the surface of the water as the vessel heels over.

2. A rudder post according to claim 1, wherein the pivotable means comprises a ring constrained from moving longitudinally with respect to the rudder post, and a swivel one part of which is anchored to the stern of the vessel whilst the other is secured to the ring.

3. A rudder post according to claim 2, wherein the rudder post is provided with a neck zone of reduced diameter, the ring being constrained within this neck zone.

4. A rudder post according to claim 2, wherein the rudder post is provided with a pair of annular flanges, the ring being constrained within the annular flanges.

5. A rudder post according to any one of the preceding claims, wherein said inclination adjusting means comprises an arcuate member fixable to the stern of the vessel, one side face of said arcuate member being provided with a plurality of serrations or undulations into which the upper part of the rudder post can engage.

6. A rudder post according to claim 5, wherein the serrations or undulations are equi-spaced from one end to the other.

7. A rudder post according to claim 5, wherein the serrations or undulations are unequally spaced, there being more per unit length at the centre of the arcuate member than at the ends.

8. A rudder post according to claim 1, including means for sensing whether or not the rudder post is vertical; servocontrol means energized from said sensing means for moving said rudder post so as to maintain the rudder post in the vertical position at all times.

9. A rudder post according to claim 8, wherein said sensing means comprises a double acting mercury switch.

10. A rudder post according to claim 8 or 9, wherein said servo-control means comprises an electric motor, a horizontal shaft one end of which is connected to the rudder post, gearing connectable between the other end of the shaft and the electric motor, and a control circuit for providing a control current to the armature winding of the motor in accordance with signals received from said sensing means.

11. A rudder post for marine vessels, constructed substantially as herein described with reference to and as illustrated in Figs. 3 to 6, or Fig. 7, or Fig. 8 of the accompanying drawings.