A ship with a ship hull thruster

Abstract

A ship hull thruster that offers excellent manoeuvrability without increasing sailing resistance. The ship hull thruster comprises a water duct comprising a water inlet at a first end of said water duct and a water outlet at a second end of said water duct; at least one water pump enclosed in the first end of said water duct for pumping water towards the second end of the water duct, wherein said nozzle is rotatable by an angle up to 360 degrees around an axis parallel to a yaw axis of the ship, and wherein the nozzle comprises structural ribs assembled to outer lining substantially aligned with lines of a ship hull when the hull thruster is in a non-operational position.

Description

[0001] The invention relates to the field of a steering and propulsion mechanism of a ship, particularly it relates to a ship with a ship hull thruster.

[0002] Ship hull thrusters, or tunnel thrusters, are widely used devices to assist in maneuvering the ship in port. They comprise e.g. transverse tunnel thrusters and, channel bow thrusters. The problem with these known hull thrusters is that they combine increasing sailing resistance with increasing maneuverability. They can either have small additional sailing resistance with reduced maneuverability or larger sailing resistance while increasing maneuverability.

[0003] Some designs include external thruster nozzles with limited size and high water pressure, this compromise reduces the sailing resistance compared to normal thrusters, but also reduces the efficiency of the thruster, an example is shown in GB1194510A.

[0004] Some designs position the water inlet at the forward side of the hull to reduce the resistance of the opening. This however, has the negative effect that all particles in the water will gather in this opening.

[0005] EP2407373, EP0024443 and GB658822 disclose a steering grid thruster that has relatively lower sailing resistance but requires a flat bottom that is sensitive to slamming damage. Further, the effectiveness is reduced because the outflow is partly directed in a vertical downward direction. GB1194510, CN108910004 and JPS5671694 disclose a hull thruster comprising a rotatable nozzle protruding outside the ship hull which increase the sailing resistance. US3710748 solves the issue of increase sailing resistance by including foldable valves in openings at the forward of the ship, but the device cannot direct the water stream in a 360 degrees orientation. Equally, the devices of DE3334254 and GB1378120 can only direct the water stream in either sideways to the ship or astern direction, the latter can also direct the water stream ahead through special tunnel shapes in hull. Nowadays, ten thousands of seagoing ships sail daily around the world, an increased sailing resistance of even 1% translates in a significant financial loss due to the increase in fuel consumption, not to mention the increases damage to the environment by the increased release of greenhouse gases.

[0006] US2016347433 discloses a jet-propelled boat with two outlets-one located aft for forward thrust and one located in the bow rotatable for steering or maneuverability.

[0007] US3362371 discloses a hydraulic jet propulsion system for a watercraft, consisting of a housing with water inlet and outlet, a nacelle containing a rotary impeller with asymmetric rotor blades, and mechanical means to drive it. The nacelle can pivot about an axis perpendicular to the impeller's rotation, controlled by a rotatable shaft, allowing both thrust generation and directional control by redirecting the water jet.

[0008] GB1194510 discloses a ship provided with a ship hull thruster according to the preamble of claim 1.

[0009] It is an object of the current invention to correct the shortcomings of the prior art and to provide a ship hull thruster that offers an increased maneuverability of the ship without increasing the sailing resistance.

[0010] This and other objects which will become apparent from the following disclosure, are provided with a ship hull thruster having the features of one or more of the appended claims.

[0011] In a first aspect of the invention, the nozzle is provided with an outer lining and is embodied with an operational position and a non-operational position, wherein in the non-operational position said outer lining uninterruptedly continues a contour of the ship's hull.

[0012] To provide the outer lining of the nozzle with sufficient strength, it is preferred that the nozzle comprises structural ribs that are assembled to the outer lining.

[0013] During sailing, when the ship hull thruster is not operational, the nozzle may be rotated in a way that the outer lining covering the nozzle aligns with the lines of the ship hull. The hull keeps its original shape as if the nozzle is not present. This feature allows the installation of the hull thruster of the invention without increasing the sailing resistance. The rotatability of the nozzle by an angle up to 360 degrees provides the ship with excellent maneuverability in the port and at sea in all directions.

[0014] Besides the obvious maneuverability advantage of being able to rotate the nozzle sideways, the nozzle may be rotated in a 180 degrees angle for emergency propulsion for the ship sailing astern. For steering whilst sailing astern, the thruster angle can be rotated from the 180 degree midpoint to either sides.

[0015] Advantageously, for an increased efficiency and to suck as little air as possible, the first end of the water duct and the second end of the nozzle are preferably submergible below the ship's waterline. The waterline position depends on the weight of cargo and ballast carried by the ship. Preferably, the nozzle is located below the waterline. However, with lighter cargo / ballast the waterline may be lowered and the nozzle might, at least partially, be above the waterline.

[0016] More advantageously, a second end of the nozzle may be oriented towards, preferably facing, the first end of the water duct when the nozzle is in a non-operational position. This is the case when the hull thruster is not operating.

[0017] Suitably, the nozzle is configured to be curved by an angle between 60 and 150 degrees. More suitably, the nozzle is configured to be curved by an angle of 90 degrees. This allows the water to flow in a substantially horizontal direction out of the nozzle resulting in a more efficient push.

[0018] In order to increase the rigidity of the structure, the second end of the nozzle may be fluidly connected to the first end of the water duct, when the nozzle is in a non-operational position. Advantageously, the first end of the water duct may be covered by the second end of the nozzle

[0019] The water pump comprises at least one propeller perpendicularly attached to a propeller shaft. This is the simplest form of a water turbine that can be replaced by any other form of more complex water turbine.

[0020] To increase the efficiency of the water pump, the first end of the water duct may be slanted downwards forming an angle between 0 and 90 degrees with the waterline. Suitably, the first end of the water duct may be slanted downwards wherein the inlet is pointing towards a main sailing direction of the ship.

[0021] Advantageously, the outer lining of the nozzle may be configured to form at least one V-shaped edge for facilitating water flow separation during sailing at sea including 'cutting' waves and preventing bottom slamming when the nozzle is in a non-operational position during sailing.

[0022] The nozzle may be fluidly and rotatably connected to the first end of the water duct via a swivel pipe connected to steering gears via a rudder stock. The swivel pipe offers a water-tight connection to the water duct, while allowing the nozzle to be freely rotated by the action of the steering gears on the rudder stock.

[0023] During sailing, the nozzle may be pulled up and locked to increase the rigidity of both the hull and nozzle structure. For this purpose, the rudder stock may be connected to the steering gears via an interlocking shaft coupling device comprising upper slanted ridges engaging lower slanted ridges for locking the nozzle to the ship hull in an upward position when the nozzle is in a non-operational position during sailing by transforming a rotational motion of the steering gears into an upwards motion of the rudder stock, and by transforming a rotational motion of the steering gears into a downwards motion of the rudder stock for unlocking the nozzle for the purpose of placing the nozzle in an operational position during port maneuvers. Also other mechanical systems can be used including but not limited to (vertical) hydraulic cylinders.

[0024] The water duct comprises at least in part a rectangular cross section to reduce turbulences inside the water duct.

[0025] For optimal hydrodynamic flow continuity, the water duct comprises at least in part a circular cross section near pump / propeller and nozzle connection.

[0026] The water duct comprises at least one protrusion on an inside surface of said water duct, to enhance the flow and reduce turbulences inside the water duct.

[0027] Advantageously, for a stronger water stream, a longitudinal dimension of the nozzle is larger than a transverse dimension of said nozzle, optionally, measured at a central point of the nozzle.

[0028] The propeller tube around the shaft may comprise a plurality of radially fixed fins for partially recuperating a rotation energy of said propeller shaft.

[0029] The water pump may comprise two counter-rotating propellers attached to a propeller shaft to improve the propulsion efficiency and reduce the rotational flow of the water stream.

[0030] An upper side of the water duct may comprise an opening connected to an air pump for removing air from said water duct.

[0031] The water inlet may comprise protective gratings to protect the water pump from debris.

[0032] On one hand, for higher thruster efficiency a larger cross-section area of the nozzle outlet is advantageous. On the other hand, reducing the cross-section area of the nozzle outlet, like it is done in GB1194510, reduces the additional sailing resistance, this however, has a negative effect on the efficiency of the thruster itself. The nozzle opening of the current invention may be hidden inboard of the hull lines when the nozzle is in a non-operational mode. Therefore, the outlet opening does not need to be reduced in size nor the efficiency compromised. The outlet opening (6.2) of the nozzle (6) can therefore have a cross-section area of at least 50% of the cross-section area of the water inlet.

[0033] Advantageously, a rotation axis of nozzle forms an angle up to 30° with a yaw axis of the ship.

[0034] More advantageously, a rotation axis of the propeller shaft forms an angle up to 45° with a yaw axis of the ship.

[0035] In a further embodiment of the invention, the water duct may be embedded inside the nozzle.

[0036] Suitably, the water duct may be coaxially embedded inside the nozzle, wherein the water duct and the nozzle are rotatable by an angle up to 360 degrees around an axis parallel to a yaw axis of the ship.

[0037] Alternatively, the water duct may be fixed and the nozzle may be rotatable by an angle up to 360 degrees around an axis parallel to a yaw axis of the ship.

[0038] For increased efficiency of water inflow and lowered resistance, the first end of the water duct and / or the first end of the nozzle may comprise rounded edges.

[0039] For reduced water stream drag, the second end of the water duct and / or the second end of the nozzle may comprise sharp edges.

[0040] Advantageously, the water duct opening and / or the nozzle opening may comprise a radius larger than 50 mm.

[0041] The invention will hereinafter be further elucidated with reference to the drawing of an exemplary embodiment of a hull thruster according to the invention that is not limiting as to the appended claims.

[0042] In the drawing: figure 1 shows the ship hull thruster of a ship according to the invention in a side view; figure 2 shows the ship hull thruster of a ship according to the invention in a side view; figures 3, 4 and 5 show the ship hull thruster of a ship according to the invention in multiple views; figure 6 shows the ship hull thruster as part of a ship according to the invention in section view showing the left side of the ship; figure 7 shows the ship hull thruster in a zoomed view (left) and in a side section view (right); and figure 8 shows the ship hull thruster as part of a ship according to the invention in a schematic side view; figures 9, 10 and 11 show the ship hull thruster of a ship according to the invention in multiple schematic views; figure 12 to 15 show the ship hull thruster of a ship according to the invention in side views and cross section views, wherein the top-right of figures 14 and 15 show the ship hull thruster of the invention in an exploded view.

[0043] Whenever in the figures the same reference numerals are applied, these numerals refer to the same parts.

[0044] The ship hull thruster 1 as depicted in figures 2-10 is part of a ship according to the invention, and for clarity shown isolated from the remainder of the ship. The skilled person understands however that the ship hull thruster 1 as depicted in figures 2-10 may be placed in a bow area of the ship of the invention as depicted in figure 1. The hull thruster 1 may also be placed in a keel region or stern region of the ship.

[0045] Figure 2 shows that the nozzle 6 in a non-operational position. More details are shown in figure 3 namely the smooth integration of the outer lining 7 provided to the nozzle 6 of the ship hull thruster 1, with the hull of the ship when the nozzle 6 is in a non-operational position. Figure 4 and 5 show the nozzle 6 rotated by 90 (for sideways pushing) and 180 degrees (for reverse / emergency propulsion) respectively. Figure 6 shows the outer lining 7 of the nozzle 6 comprising structural ribs 8 assembled to the outer lining 7 which is aligned with hull line of the ship for smooth integration with the hull of the ship when the nozzle 6 is in the non-operational position. This feature allows the installation of the thruster without increasing the sailing resistance.

[0046] The ship hull thruster is shown located inside the hull of the ship. The left side of figure 7 offers a zoomed view on the interlocking coupling device 12 that connects the rudder stock 11 to the steering gears 10. The upper slanted ridges 13.2 engage the lower slanted ridges 13.1 when the steering gear 10 rotate in order to pull the rudder stock 10 upwards to lock it during sailing or downwards to unlock it during maneuvering at the port.

[0047] The right side of figure 7 shows how the outside lining of the nozzle 6 smoothly aligns with the contour of the ship hull when the nozzle 6 is pulled up and locked during sailing.

[0048] In case of failure of the main engine of the ship, the ship hull thruster 1 may be used as an emergency measure by placing the nozzle 6 in an operational position and rotating the nozzle 6 to an angle of 180 degrees with reference to the ship's desired sailing direction, as shown in figure 8. Hence, the vessel can be pushed in aft ward direction.

[0049] The hull thruster may also be placed in a keel region of the ship as depicted in figures 9 to 11, wherein figure 9 shows the thruster 1 of the invention in a non-operational mode, figure 10 shows the thruster 1 of the invention in operational mode rotated 90 degrees for side pushing / thrusting, and figure 11 shows the thruster 1 of the invention rotated 180 degrees for emergency pushing / thrusting.

[0050] Figures 12 and 13 show a second embodiment of the invention wherein the water duct (2) is coaxially embedded inside the nozzle (6) and wherein the water duct (2) and the nozzle (6) are rotatable around an axis parallel to a yaw axis of the ship. The water duct (2) and the nozzle (6) are shown attached to a cylindrical pipe structure rotatably sleeved inside the hull of the ship. Figure 12 show the nozzle (6) in non-operational mode and figure 13 show the nozzle in an exemplary operational mode wherein both the nozzle (6) and the water duct (2) are rotated by 90 degrees.

[0051] Figures 14 and 15 show a third embodiment of the invention wherein the water duct (2) is embedded inside the nozzle (6) and wherein the water duct (2) is fixed to the hull of the ship in a 90° transverse position and only the nozzle (6) is rotatable around an axis parallel to a yaw axis of the ship. Figure 14 show the nozzle (6) in non-operational mode and figure 15 show the nozzle in an exemplary operational mode wherein the nozzle (6) is rotated by 90 degrees. The water duct (2) remains in 90° transverse fixed position.

[0052] Figure 16 explains the importance of part of the propeller extending below the enclosed air space in the duct 2. Figure 16A shows a typical ship hull thruster, and figure 16B shows the ship hull thruster according to the invention. When an enclosed duct with openings towards the bottom is submerged, air remains in the top part of the duct. When a propeller solely rotates in air, see figure 16A, the pump effect is limited and the air bubble remains in the duct. However, when the propeller partially or fully extends into the water, see figure 16B, the propeller can start to push the water into the duct and press the air out. The effect is that after starting the propeller, the air is soon removed and full thrust can be achieved. A line (20) is drawn, indicating the outer water level. If the propeller blade (5.1b) is positioned above the second end (2.2) of the water duct (2) like as depicted in figure 16A, the pumping action will not work properly. However, when the propeller blades (5.1a) extend, even partially, below the second end (2.2) of the water duct (2) the propeller blades (5.1a) will push the air outside when they rotate and the ship hull thruster will start the propulsion.

[0053] Although the invention has been discussed in the foregoing with reference to an exemplary embodiment of the method of the invention, the invention is not restricted to this particular embodiment which can be varied in many ways without departing from the invention. The discussed exemplary embodiment shall therefore not be used to construe the appended claims strictly in accordance therewith. On the contrary the embodiment is merely intended to explain the wording of the appended claims without intent to limit the claims to this exemplary embodiment. The scope of protection of the invention shall therefore be construed in accordance with the appended claims only, wherein a possible ambiguity in the wording of the claims shall be resolved using this exemplary embodiment. The nozzle 6 can be fitted in bow, stern or any other (partially) outward shaping hull form.

Claims

1. A ship with a ship hull thruster (1) comprising: - a water duct (2) comprising a water inlet at a first end (2.1) of said water duct and a water outlet at a second end (2.2) of said water duct; - at least one water pump (5) enclosed in said water duct (2) for pumping water towards the second (2.2) end of the water duct; and - a nozzle (6) rotatable by an angle up to 360 degrees around an axis substantially parallel to a yaw axis of the ship, characterized in that the nozzle (6) is provided with an outer lining (7) and is embodied with an operational position and a non-operational position, wherein in the non-operational position said outer lining uninterruptedly continues a contour of the ship's hull and the first end (2.1) of the water duct (2) is covered by the nozzle (6).

2. The ship of claim 1, characterized in that the first end (2.1) of the water duct (2) is covered by the second end (6.2) of the nozzle when the nozzle (6) is in the non-operational position.

3. The ship according to claim 1 or 2, characterized in that the nozzle (6) comprises structural ribs (8) assembled to said outer lining (7).

4. The ship according to any one of the preceding claims, characterized in that a first end (6.1) of said nozzle is fluidly and rotatably connected to the second end (2.2) of the water duct (2).

5. The ship according to any one of the preceding claims, characterized in that a second end (6.2) of the nozzle (6) is oriented towards the first end (2.1) of the water duct (2) when the hull thruster (1) is in a non-operational position, wherein optionally, the first end (2.1) of the water duct and the second end (6.2) of the nozzle are submergible below the ship's waterline.

6. The ship according to any one of the preceding claims, characterized in that the nozzle (6) is configured to be curved by an angle between 60 and 150 degrees.

7. The ship according to any one of the preceding claims, characterized in that the first end (2.1) of the water duct (2) is slanted downwards forming an angle between 0 and 90 degrees with the ship's waterline, wherein optionally, the first end (2.1) of the water duct is slanted downwards, wherein the inlet is pointing towards a main sailing direction of the ship.

8. The ship according to any one of the preceding claims, characterized in that the outer lining (7) of the nozzle (2) is configured to form at least one V-shaped edge for facilitating water flow cutting and / or separation during sailing when the nozzle (6) is in a non-operational position.

9. The ship according to any one of the preceding claims, characterized in that the nozzle (2) is fluidly and rotatably connected to the first end (2.1) of the water duct via a swivel pipe (9) connected to steering gears (10) via a rudder stock (11).

10. The ship according to any one of the preceding claims, characterized in that at least a portion of the water duct (2) comprises a rectangular cross section, wherein optionally, the propeller shaft (5.2) is configured to be supported by a frame comprising a plurality of radial fins (5.3) for partially recuperating a rotational kinetic energy of said propeller (5.1), wherein more optionally, an upper side of the water duct (2) comprises an opening connected to an air pump for removing air from said water duct.

11. The ship according to any one of the preceding claims, characterized in that a longitudinal dimension of the nozzle is larger than a transverse dimension of the nozzle (6), optionally, measured at a central point of the nozzle (6), wherein more optionally, the second end (6.2) of the nozzle (6) has a cross-section area of at least 50% of a cross-section area of the water inlet (2.1).

12. The ship according to any one of the preceding claims, characterized in that the propeller blades (5.1a) are configured to extend at least partially below the second end (2.2) of the water duct (2).

13. The ship according to any one of the preceding claims, characterized in that a rotation axis of the nozzle (6) forms an angle (β) up to 30° with a yaw axis of the ship, wherein optionally, a rotation axis of the propeller shaft (5.2) forms an angle up to 45° with a yaw axis of the ship.

14. The ship according to any one of the preceding claims, characterized in that the first end (2.1) the water duct (2) and / or the first end (6.1) of the nozzle (6) comprise rounded edges, wherein optionally, the second end (2.2) of the water duct (2) and / or the second end (6.2) of the nozzle (6) comprise sharp edges.

15. The ship according to any of the preceding claims, characterized in that the water duct (2) is embedded inside the nozzle (6), wherein optionally, the water duct (2) is coaxially embedded inside the nozzle (6), wherein more optionally, the water duct (2) and the nozzle (6) are rotatable by an angle up to 360 degrees around an axis parallel to a yaw axis of the ship.

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