GB2337240A

GB2337240A - Propulsion unit

Info

Publication number: GB2337240A
Application number: GB9911052A
Authority: GB
Inventors: Mark Victor Wilkins
Original assignee: Individual
Current assignee: Individual
Priority date: 1998-05-13
Filing date: 1999-05-12
Publication date: 1999-11-17
Anticipated expiration: 2019-05-12
Also published as: GB9911052D0; GB2337240B; GB9810169D0

Abstract

A propulsion unit for a marine vehicle comprises passage (2) having an inlet (2a) at one end, and first and second diverging outlets (2b and 2c) at the other end. An impeller (4) is positioned within the passage (2) for forcing water through the passage from the inlet (2a) to at least one of the outlets (2b, 2c). A valve (6) is positioned within the passage (2) in the region where the two outlets (2a and 2b) diverge. The valve (6) is movable from a first end position in which the first outlet (2b) is closed and the second outlet (2c) is open, through an intermediate position in which both outlets are open, to a second end position in which the first outlet is open and the second outlet is closed.

Description

2337240 PROPULSION LM1 This invention relates to a propulsion unit for a

ship, and in particular to an auxiliary propulsion unit for manoeuvring a ship.

Ships are traditionally manoeuvred into, and out of, berths in harbours and ports by tugs. In busy harbours and ports, however, there is often a shortage of tugs, which can lead to delays in the full utilisation of berths, as well as posing serious safety threats. Narrow fairways also give rise to manoeuvrability problems, and can result in ships being grounded.

It is known to provide ships with auxiliary propulsion units for use during manoeuvring. A known type of auxiliary propulsion unit is known as a tunnel thruster. This tunnel thruster includes a propeller unit which consists of a tunnel housing a propeller hub which is driven, via a propeller shaft and an internal bevel gear drive, by an electric motor. The tunnel extends transversely through the hull of the ship from port to starboard, the tunnel being open to the sea at both ends. In order to manoeuvre the ship, the propeller is driven in one direction to force water through the tunnel from the port side to the starboard side, and in the other direction to force water from the starboard side to the port side. In the former case, the ship is manoeuvred sideways towards port and, in the latter case, the ship is manoeuvred sideways towards starboard. Typically, a ship will have at least one tunnel thruster at the bow, and at least one tunnel thruster at the stem.

The disadvantage of tunnel thrusters of this type is their lack of versatility, and in particular the lack of control of the direction of thrust water this being at right-angles to the longitudinal axis of the ship, either to port or starboard.

The aim of the invention is to provide a more versatile auxiliary propulsion unit for a ship.

The present invention provides a propulsion unit for a marine vehicle, the propulsion unit comprising passageway means having an inlet at one end, and 1 first and second diverging outlets at the other end, an impeller positioned within the passageway means for forcing water through the passageway means from the inlet to at least one of the outlets, and a valve positioned within the passageway means m the region where the two outlets diverge, the valve being movable from a first end position in which the first outlet is closed and the second outlet is open, through an intermediate position in which both outlets are open, to a second end position in which the first outlet is open and the second outlet is closed.

In a preferred embodiment the propulsion unit fiu-ther comprises a motor in drivable engagement with the impeller via a drive shaft. Preferably, the motor is an electric motor. The motor may be positioned outside the passageway means, the drive shaft passing through, and being sealed relatively to, the wall of the passageway means.

Advantageously, the propulsion unit further comprises drive means for moving the valve from one end position to the other. Preferably, the drive means is constituted by hydraulic drive ineans.

Conveniently, the passageway means comprises a first passage leading from the inlet to the valve, and a pair of diverging second passages leading from the valve to the first and second outlets, the impeller being positioned within the first passage.

In a preferred embodiment, a respective nozzle is rotatably associated with each of the outlets, the nozzles being rotatable in such a manner that each can direct water firom the associated outlet in a direction away from the inlet and in the direction of the axis of the first passage, in a direction at right- angles to said axis, or in any direction therebetween.

Advantageously, the propulsion unit further comprises nozzle drive means for controllably rotating the nozzles. The nozzle drive means may be constituted by individual gear drives to each nozzle, and control means for controlling the gear drives.

An auxiliary propulsion unit constructed in accordance with the invention will now be described in detail, by way of example, with reference to the drawings, in which:Figure 1 is a schematic plan view of the stem of a ship provided with the auxiliary propulsion unit; is a schematic side elevation of the arrangement shown in Fig. 1: and are enlarged schematic views of a rotating nozzle forming part of the propulsion unit the nozzle being shown in two different operating positions.

Referring to the drawings, an auxiliary propulsion unit (indicated generally by the reference P) is fitted in the hull of a ship 1 (only the stem of which can be seen in the drawings). The unit P includes a tunnel 2 having a water inlet 2a and two diverging water outlets 2b and 2c. A respective outlet water nozzle 3 is rotatably mounted at the free end of each of the water outlets 2b and 2c. An impeller 4 is mounted within the tunnel 2 substantially midway between the inlet 2a and the outlets 2b and 2c. The impeller 4 is in drivable engagement with an electric motor 5 via an impeller drive shaft 4a. A valve 6 is positioned within the tunnel housing 2, and is movable from a position in which it completely blocks the outlet 2b, through the position shown (in which both outlets are unblocked) to a position in which it completely blocks the outlet 2c. The valve 6 is movable, via a valve arm 7, by a hydraulic drive means (not shown).

In use, actuating the motor 5 drives the impeller 4 which draws in water through the inlet 2a and forces water out through either or both the outlets 2b and 2c, depending upon the position of the valve 6.

As shown best in Figures 3a and 3b, each nozzle 3 is rotatably mounted on a U-shaped flange lb or lc which connects the free end of the associated outlet 2b or 2c to the hull 1 of the ship. Each nozzle 3 is rotatable, relative to its respective water outlet 2b or 2c, by means of gearing (not shown) from the Figure 2 Figures 3a and 3b position shown in Figure 3b, in which water can be directed generally at rightangles to the longitudinal axis of the ship 1 (as indicated by the arrows B), to a position (shown in Figures 1 and 3a) in which water can be directed generally axially and away from the stem of the ship (as indicated by the arrows A). Obviously, the nozzles 3 can also be positioned in any intermediate position between these two rotational end positions, thereby perinitting water to be directed away from the hull of the ship at any angle.

The unit P has, therefore, the ability to direct water aft, to port or to starboard. Thus, the unit P can provide flill power aft to move the ship 1 forwards, full power to port to move the ship to starboard, flill power to starboard to move the ship to port, half power aft and half power to port to move the ship forward and to starboard, half power aft and half power to starboard to move the ship forward and to po^ or half power to port and half power to starboard to maintain the ship in its current position (station keeping).

is The unit P will typically be used when docking or when manoeuvring in confined spaces. During docking, the main propeller(s) or main engine(s) can be damaged by debris (such as rope, driftwood, chains etc). Propellers and main engines are expensive and difficult to replace. By using the unit P instead of these items, such damage is prevented. Moreover, as the movable parts of the unit P are within the hull of the ship 1, they are unlikely to be damaged by such debris. The unit P could also be used when the ship's main engines fail. In particular, the unit P could be used, at sea, if the ship's main engines fail, thereby pernlitting the ship to limp home.

Ships fitted with the auxiliary propulsion unit of the invention will also have the advantage of readily available emergency power either for auginenting or replacing the main engines. In the event of rudder failure, this unit can also be used to steer the ship. Thus, the safety of ships can be improved by fitting this auxiliary propulsion unit.

Claims

Clai!ns

1. A propulsion unit for a marine vehicle, the propulsion unit comprising passageway means having an inlet at one end, and first and second diverging outlets at the other end, an impeller positioned within the passageway means for forcing water through the passageway means from the inlet to at least one of the outlets, and a valve positioned within the passageway means in the region where the two outlets diverge, the valve being movable from a first end position in which the first outlet is closed and the second outlet is open, through an intermediate position in which both outlets are open, to a second end position in which the first 10 outlet is open and the second outlet is closed.

2. A propulsion unit as claimed in claim 1, further comprising a motor in drivable engagement with the impeller via a drive shaft.

3. A propulsion unit as claimed in claim 2, wherein the motor is an electric 6.

motor.

4. A propulsion unit as claimed in claim 2 or claim 3, wherein the motor is positioned outside the passageway means, the drive shaft passing through, and being sealed relatively to, the wall of the passageway means.

5. A propulsion unit as claimed in any one of claims 1 to 4, further comprising drive means for moving the valve from one end position to the other.

A propulsion unit as claimed in claim 5, wherein the drive means is constituted by hydraulic drive means.

7. A propulsion unit as claimed in any one of claims 1 to 6, wherein the passageway means comprises a first passage leading from the inlet to the valve, and a pair of diverging second passages leading from the valve to the first and second outlets, the impeller being positioned within the first passage.

8. A propulsion unit as claimed in claim 7, wherein a respective nozzle is rotatably associated with each of the outlets, the nozzles being rotatable in such a manner that each can direct water from the associated outlet in a direction away from the inlet and in the direction of the axis of the first passage, in a direction at right-angles to said axis, or in any direction therebetween.

9. A propulsion unit as claimed in claim 8, flu-ther comprising nozzle drive means for controllably rotating the nozzles.

10. A propulsion unit as claimed in claim 6, wherein the nozzle drive means is constituted by individual gear drives to each nozzle, and control means for controlling the gear drives.