GB2060533A

GB2060533A - Steering Arrangement for Watercraft

Info

Publication number: GB2060533A
Application number: GB7934112A
Authority: GB
Original assignee: Rudd K N
Current assignee: Rudd K N
Priority date: 1979-10-02
Filing date: 1979-10-02
Publication date: 1981-05-07
Also published as: GB2060533B

Abstract

The propeller shaft 11 of a watercraft is connected to the drive shaft 9 from an inboard engine by a universal coupling 12 having its pivot centres on the same vertical axis as the hinges 4, 5 of a rudder blade 3 and the propeller and rudder blade are swung together about this axis to steer the craft. Thrust of the propeller is transmitted through the blade 3 to the hinges 4, 5 by a bearing 13 of the propeller shaft 11. <IMAGE>

Description

SPECIFICATION Steering Arrangement for Watercraft This invention is concerned with steering arrangements for watercraft such as ships, boats, yachts and the like, and in particular to such craft equipped with single screw propulsion either as a main unit or as an auxiliary to sail.

Problems associated with the operation of such watercraft are well known and include all the movements associated with changing direction and going astern.

For vessel proceeding from a standstill, the problem is accentuated, as the torque of the propeller exerts a side-thrust before the vessel has steerage way, and this produces inaccuracies demanding high skills to counteract.

Bringing a vessel to a standstill while it has forward way produces another set of problems.

The engaging of reverse thrust, whilst slowing the craft, reduces water flow over the rudder drastically, applying at the same time torqueinduced sideways drift; if these are not fully compensated, then the vessel may get out of control.

In circumstances where an emergency stop is required, these effects may have to be tolerated in the interests of avoiding an immediate collision, but may well result in other dangeous side effects which can lead to craft into navigational hazards.

Changing course in a large vessel having comparatively shallow draft, and relying on water speed past the rudder to exercise control is a slow and, sometimes, impossible task. Putting hard astern produces the results described, and thus there are sometimes no options left but to try and arrest the progress of the ship by slow astern before she sails into danger.

Steerable propellers installed in an inboard motorised vessel have been used in an attempt to overcome these problems. Other proposals have been to incorporate the propeller within the rudder blade so that the propeller swings with the blade. Such proposals have required complicated arrangements of gearing to drive the propeller whilst allowing the rudder blade to be swung for steering purposes.

From one aspect, the present invention provides a watercraft having a rudder blade, a propeller rotatable in a plane opened from said rudder blade about a horizontal axis and driven by an inboard engine through a universal coupling allowing movement of the propeller in a horizontal plane and means for effecting said movement in coordination with the steering movement of the rudder blade.

In an preferred form, the pivot centres of the universal coupling are aligned with the rubber hinges which accept the thrust of the propeller mounted on a separate bearing (or bearings) in the body of the rudder blade. Operation of the rudder coincidentally moves the propeller also and the thrust line is always in line with the plane of the rudder.

In another form the rudder may be arranged to follow through with the propellor until the maximum angle acceptable by the universal joint and then continue to apply more rudder after that.

On return, the rudder would first move until in line with the propeller and then line up with it until the straight ahead position.

In yet another form, the maximum area of the rudder may differ from that of the propeller and when the rudder is moved through a proportion of its arc, the propeller may be caused by links or other means to move through the same proportion of the arc.

The propeller is preferably in close proximity to the leading edge of the rudder blade which may be cut out to accommodate the end of the propeller shaft.

With the arrangement of the present invention, it is not necessary for the craft to be moving to become manoeuvrable. Dependent upon the various factors of power available, draft/length ratios etc., the ability of the craft to make turns is increased, it is able to go astern at full power and compensate for torque by turning the helm, maintaining steerage right through to 'stop' and 'reverse'.

It is not essential that the rudder by hinged on the same axis as the universal coupling. Provided that coordination is achieved, the rudder can be caused to adopt the appropriate angle to match that of the propeller by mechanical, electrical, or hydraulic couplings.

Other parts of the invention are embodied in the preferred form which will now be described by way of example with reference to the accompanying drawings, in which: Figure 1 is a side view of the steering arrangement; and Figure 2 is a rear view.

As shown, an inboard motorised craft has a hull 1 with a dead-wood keel 2. A rudder blade 3 is mounted in upper and lower hinges 4, 5 and is steerable about a vertical axis through these hinges by a steering wheel 6 through bevel gearing 7 and shaft 8.

A shaft 9 extends rearwardly from the keel 2 and is driven by an inboard engine (not shown).

A propeller 10 mounted on a horizontal shaft 11 is connected to the shaft 9 by a universal coupling 12, the pivot centres of which lie on the axis of the rudder hinges 4, 5 so that the propeller is swingable horizontally about this axis. The propeller shaft 9 is supported by a bearing 13 aft of the universal coupling of the rudder blade 3 so that the propeller swings with the rudder and is maintained with its thrust always in line with the rudder blade.

The rudder blade is cut out at its leading edge to provide a space 14 in which the propeller is situated in close proximity to the blade. The shaft 11 is as shown supported at its-rearward end by a bearing 15 in the rudder blade. The propeller thus has a bearing fore and aft, the rear one being in a tapered nacelle 16, which adds the advantage of smoothing the turbulence over the blade for better effect.

When the vessel is in reverse thrust, the bearing in this housing accepts that thrust with attendant engineering advantage.

The hinges 4, 5 are designed to accept the thrust of the propeller, which is now mounted on its own separate bearing, or bearings, in the body of the rudder blade. Because the prop-shaft is now free of thrust loads, it can be designed to accept more tolerance of angle relative to the propeller, and the undesirable downward tilt that designers are obliged to accept when installing engines in some sailing craft can be eliminated or relieved by allowing some angular deflection in the coupling in the vertical plane.

It will be apparent that the universal joint between the propeller and its driving shaft allows the movement of the propeller in a horizontal plane through angles sufficient to produce sideways thrusts from stationary positions, giving added manoeuvrability without the necessity of a water flow over the rudder.

Claims

1. A watercraft having a rudder blade, a propeller rotatable in a plane from said rudder blade about a horizontal axis and driven by an inboard engine through a universal coupling allowing movement of the propeller in a horizontal plane and means for effecting said movement in coordination with the steering movement of the rudder blade.

2. A watercraft having a rudder blade, a propeller rotatable about a horizontal axis mounted forwardly of said rudder blade, a universal joint connecting the shaft of said propeller to a drive shaft from an inboard engine, the pivot centres of said universal coupling being aligned with the hinges of said rudder blade and means for swinging said rudder blade with said propeller about the hinges thereof.

3. A watercraft as claimed in either of the preceding claims, in which the propeller is mounted on a bearing in the rudder blade whereby the thrust of said propeller is transmitted to the hinges of said rudder blade.

4. A watercraft as claimed in Claim 3, in which the shaft of the propeller is supported by bearings on the rudder plate both fore and aft of the propeller.

5. A watercraft as claimed in any of the preceding claims in which the propeller is mounted in close proximity to the leading edge of the rudder blade, which edge is cutout to accommodate the propeller.

6. A watercraft substantially as described with reference to the accompanying drawings.