TECHNICAL FIELD:

The present invention relates to a vane arrangement for a marine vessel according to the preamble of claim 1.

BACKGROUND OF THE INVENTION:

It is known to provide a propeller on marine vessels with different arrangements to increase efficiency and propulsion. One solution is to provide a nozzle arrangement, i.e. a cylindrical ring which encloses or partly encloses the propeller, whereby the nozzle generates a forwardly directed force which is produced by the propeller jet contraction and pressure field because the mass flow of water is larger than for a propeller without a nozzle.

The above-described method for controlling the flow of water is known from O-94/20362 in which a nozzle which is stationary about a propeller encloses the entire propeller and is provided with guiding vanes in front of and/or behind the propeller. The guiding vanes are used to convert the rotating kinetic energy from the propeller into traction force, i.e. the guiding vanes control the flow of water through the nozzle to thereby increase the efficiency and the propulsion. Said document further discloses that the whole arrangement, with propeller and nozzle, may have a pivotal and tiltable function to further control the flow of water and to thereby impart a rudder effect to the vessel upon which the arrangement is mounted. However, this solution is relatively expensive and, furthermore, permits the vessel to roll when the vessel is in a resting position because the lateral movement which a propeller would otherwise counteract if not encapsulated is not produced.

EP-A2-165 913 discloses another form of nozzle arrangement which provides a rudder effect, wherein a stationary nozzle encloses the entire propeller and is provided with guiding vanes behind the propeller. The guiding vanes are arranged both radially and transversely within the propeller housing. The purpose of the perpendicular guiding vanes is said to be to direct the propeller jet downstream for preventing the upstream propeller jet from reaching the hull of the vessel, which otherwise would increase the resistance of the vessel.

US-A-2 803 211 describes a nozzle in the form of a completely open hollow shell provided behind a propeller to provide a rudder effect. The nozzle diameter is smaller than the propeller.

SUMMARY OF THE INVENTION:

It is therefore an object of the present invention to provide a simplified vane arrangement which imparts a rudder effect to a marine vessel, at the same time that increased efficiency and improved propulsion is attained by controlling the flow of water downstream of the propeller.

This object is achieved in accordance with the present invention by a vane arrangement according to claim 1 in which the vane arrangement comprises radially extending guiding vanes on a hub.

A further object of the present invention is to provide a combined trim and steer arrangement on a vessel which also supports the vane arrangement.

This object is achieved by claim 10 in which the vane arrangement is mounted to the hull of the vessel by suspension means comprising a rudder shaft pivotally arranged within a inner disc which is pivotally arranged

within a outer disc, with the discs being accommodated within a ring-shaped housing disposed in the hull of the vessel.

Further advantages of the vane arrangement according to the present invention will be apparent from the dependent claims . A particularly advantageous embodiment is obtained when the propeller is not encapsulated by a nozzle. In this manner, the vessel is prevented from rolling when it is in a resting position because the propeller counteracts any lateral movement.

BRIEF DESCRIPTION OF THE DRAWINGS:

The invention will be described in greater detail in the following by way of example only and with reference to the attached drawings, in which

Fig. 1 is a schematic elevational view of a vane arrangement according to the present invention;

Fig. 2a,b is a sectional view through a vane arrangement according to the present invention in which a propeller is fixed to a substantially horizontal drive shaft;

Fig. 3 is a sectional view essentially corresponding to that of Fig. 2, in which the propeller is fixed to an angled drive shaft;

Fig. 4 is a sectional view of a vane arrangement according to one embodiment of the invention;

Fig. 5 is a schematic plan view of the arrangement shown in Fig. 4;

Fig. 6 is a perspective view of a vane arrangement according to a further embodiment of the invention;

Fig. 7 schematically illustrates the installation of a vane arrangement according to the present invention, in which steering means are operated by a wire or chain;

Fig. 8 is a view essentially corresponding to that of

Fig. 7, in which the steering means are operated in a similar way to that shown in Fig. 6;

Fig. 9-11 are sectional views of a further embodiment of a vane arrangement according to the present invention, and

Fig. 12 is a partial view through the steering means depicted in Fig. 9-11.

Fig. 13 shows the steering means in Fig. 12 in a view seen from above, placed in a coordinate system.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS: In accordance with the present invention, the propulsion arrangement for a marine vessel in Fig. 1 comprises a drive shaft 15 provided with a propeller 10 arranged adjacent to, and upstream (in a forward direction of the vessel) of, a vane arrangement 14, preferably made of metal alloys and/or light metals, but can also be made of composite material and/or other materials with lower strength compared to steel, such lower strength materials being suitable for use in propulsion arrangements with low speed propellers. In order to impart a rudder effect on the vessel, the vane arrangement 14 is pivotally attached to the vessel. The vane arrangement 14 consists substantially of a plurality

of guiding vanes 12 extending radially from a hub 19. Typically, the guiding vanes 12 may be 4 or more in number, preferably between 7 and 11.

In one embodiment of the invention, the vane arrangement 14 is provided with a nozzle 17 in the form of a cylindrical housing having an inlet opening adjacent to the propeller 10 and an outlet opening remote from the propeller 10. In such an embodiment, the guiding vanes 12 extend from the hub 19 radially outwardly to an inner surface of the nozzle 17. The nozzle 17 has a longitudinal extension which is preferably half or less than half of its diameter, and the diameter of the propeller 10 is preferably less than the diameter of the nozzle 17. A typical diameter of the propeller 10 is approximatly between 0,3 and 5 m. Although shown in Fig. 1 as being separated by a small gap, it is envisaged that the propeller 10 may be partially or totally enclosed by the nozzle.

In order to reduce vibrations caused by the interaction between the flow of water and the propulsion arrangement, both the guiding vanes 12 and the propeller blades are preferably skewed along their length.

Two installations of the vane arrangement 14 according to the present invention are shown in Figs. 2a, 2b and 3, in which the propeller 10 is fixed to the drive shaft 15 and the vane arrangement 14 is pivotally arranged behind the propeller 10 via pivoting means 16, typically in the form of a steering shaft extending substantially perpendicularly to the drive shaft 15, and journelled to the hull 11 of the vessel to thereby impart a rudder effect when the vane arrangement 14 is pivoted about the steering shaft. The pivoting means 16 are preferably made of metal alloys . In accordance with the invention, the vane arrangement 14 comprises radially extending guiding vanes 12 having a

leading edge and a trailing edge. In order to adjust the direction of flow of water past the vane arrangement 14, the trailing edge of one or more guiding vanes 12 may be provided with adjustable flaps (not shown) in a manner as described in said WO 94/20362. The vane arrangement 14 may also be provided with a nozzle 17. Again, as described in WO 94/20362, the nozzle too may be provided with adjustable flaps (not shown) around its inlet opening.

The arrangements shown in Figs. 2a, 2b and 3 are identical save for the fact that in Fig. 2a the propeller 10 is fixed to a substantially horizontal drive shaft 15 and the vane arrangement 14 is provided with a nozzle 17, and in Fig. 2b the vane arrangement 14 is provided without a nozzle 17 whilst in Fig. 3 the propeller 10 is fixed to an inclined drive shaft 15.

With outboard-mounted engines, it is generally desirable to be able to trim the propeller 10, i.e. alter the angle which the propeller 10 subtends with respect to the water surface, depending on the speed of the vessel. With inboard-mounted engines, however, due to the fact that the propeller 10 is attached to a fixed-angle drive shaft 15, such trim changes are not possible. With the present invention, however, and as illustrated in Figs. 4 and 5, trim adjustment may be imparted on the vane arrangement 14.

Thus, in the embodiment shown in Figs. 4 and 5, the drive shaft 15 or the propeller 10 is provided with an axial extension in the form of a radially centrally mounted ball pin 24 which is arranged to be accommodated in a bearing socket in the hub 19 of the vane arrangement 14. The ball pin 24 and bearing socket support the vane arrangement 14 and define a pivot point about which the vane arrangement 14 can be pivoted. The vane arrangement 14 is prevented from rotating about the ball pin 24 by the provision of a

pair of control rods 28 which also impart trimming and steering forces to the vane arrangement 14 in a manner which will be described in the following.

As is most clearly apparent from Fig. 5, the control rods 28 are symmetrically disposed either side of the drive shaft 15 when seen in plan view. One end of each control rod 28 is journelled to the vane arrangement by a ball and socket connection mounted on either the nozzle 17 or a suitable vane 12. The other end of each control rod 28 is arranged to be influenced by actuator means, for example in the form of a hydraulic or pneumatic-activated piston cylinder 26, 27. If it is desired to impart a rudder effect on the vane arrangement, then depending on the intended direction of the vessel, one or other of the cylinders 26, 27 is activated to cause the vane arrangement 14 to pivot about the ball pin 24, i.e. the stroke of one cylinder is increased whilst the other cylinder remains either stationary or has its stroke decreased. If it is desired to trim the vane arrangement 14, both cylinders 26,27 are activated simultaneously with an equal change of stroke. Clearly, if both a change in trim angle and steering angle are desired simultaneously, then the cylinders 26,27 are activated proportionally.

As an alternative to the pair of piston cylinders 26,27 described above, in another possible embodiment of the present invention and as illustrated in Fig. 6, trim and steering functions are attainable due to the provision of a first cardan joint 30 located between steering means 16, for example in the form of a tiller arm, and the vane arrangement 14 to thereby permit a rudder effect, anc a second cardan joint 32 located between a trim actuator and the vane arrangement 14 to thereby permit trimming of the vane arrangement 14.

Figs. 7 and 8 schematically illustrate the installation of a vane arrangement 14 according to the present invention, whereby exhaust gases, e.g. from an inboard-mounted engine, may be led into the nozzle 17, and/or to a rear edge of the guiding vanes 12, by exhaust leading means 20, suitably in the form of a conduit or tube. By leading the exhaust gases in this manner, not only is the exhaust noise suppressed, but a favourable pressure balance across the vane arrangement 14 is attained which reduces the drag force acting on the vessel.

In Fig. 7, the steering means 16 are in the form of a pulley wheel 40 fixedly attached via splines or keys to a steering shaft disposed substantially perpendicular to the propeller drive shaft 15. The pulley wheel 40 is arranged to be influenced by a wire or chain connected in any conventional manner to the helm of the vessel. In Fig. 8 the steering means 16 is operated in a similar way to that shown in Fig. 6.

As is apparent from both Figs. 7 and 8, the propeller 10 and vane arrangement 14 form a module or propulsion unit which is directly connectable to the hull 16. Thus, power from the inboard-mounted engine is transmitted to the propeller 10 on the propulsion unit via a suitable intermediate shaft arrangement.

In a further embodiment of the present invention, and as illustrated in Figs. 9 to 13, the vane arrangement 14 is suspended from the hull 11 of the vessel in such a manner that the ball pin and socket bearing arrangement described above in relation to Figs. 4 and 5 is not required. Thus, the vane arrangement 14 is suspended from the hull of the vessel via a steering shaft extending from the vane arrangement 14 to suspension means in the form of a pair of discs 42,43 mounted for rotation in a ring-shaped housing

affixed to the hull 11 of the vessel. The pair of discs 42,43 are in the form of an outer disc 43 having a diameter corresponding to the inner diameter of the ring-shaped housing, the diameter of the outer disc 43 being substantially the half propeller diameter, and an inner disc 42 which is accommodated in a circular opening of the outer disc 43, which opening is eccentric with respect to the geometric centre of the outer disc 43. The inner and outer discs 42,43 are rotatable with respect to each other, whilst the discs are slightly offset with respect to each other in the horizonal plane. The steering shaft passes through an opening in the inner disc 42 which is eccentric with respect to the geometric centre of the inner disc 42. The relative size of the discs and the position of the opening in the inner disc 42 are chosen such that in one position, the opening corresponds to the geometric centre of the ring-shaped housing, as shown in Fig. 10. The steering shaft is journelled with respect to the inner disc 42 so that it may be rotated with respect to the inner disc 42 and intersects the disc at a non-perpendicular angle.

The relative angles and eccentricities of the above- described arrangement are chosen so as to ensure that the vane arrangement 14 is pivotable about an imaginary pivot point substantially on the centre line of the hub of the vane arrangement 14, which pivot point is maintained at a constant distance from the propeller 10. The location of the pivot point corresponds to the intersection of the drive shaft axis and the centre line of the ring-shaped housing extending in a plane perpendicular to the plane of the housing. This pivot point also falls on an extension of the axis of the steering shaft.

The above-described suspension means functions in the following manner.

If it is assumed that a change in the trim angle is desired at the same time that no change in direction of the vessel is required, the outer disc 43 is rotated through an angle φ (see Fig. 13). Due to the dynamic forces acting on the vane arrangement 14 which will be transmitted to the suspension means via the steering shaft, the inner disc 42 is compelled to rotate though an angle 2φ. This causes the centre of the rudder shaft to be displaced along a substantially straight line, thereby effecting a change in trim angle of the vane arrangement 14 without affecting the steering function of the vessel. Naturally, the vessel can be steered simply by rotating the steering shaft with respect to the inner disc 42.

Of course, the above-described suspension means may be employed to suspend devices other than the vane arrangement 14 described above. For example, an entire marine propulsion unit could be so suspended from a vessel.