WO2018134469A1

WO2018134469A1 - A vessel

Info

Publication number: WO2018134469A1
Application number: PCT/FI2017/050027
Authority: WO
Inventors: Tomi Veikonheimo; Andrei KORSSTRÖM; Tero Tamminen
Original assignee: Abb Oy
Priority date: 2017-01-19
Filing date: 2017-01-19
Publication date: 2018-07-26

Abstract

The vessel comprises a hull (20) having a bottom line (BL) and a bow (30). A recess (100) is arranged in the bow above the bottom line of the hull of the vessel, the recess comprising a bottom surface (110) forming a portion of the hull of the vessel. At least one thruster (60, 70) being rotatable around a vertical axis (Y1, Y2) is positioned within the recess so that a propeller (63, 73) of the thruster in a first position, is positioned below the bottom surface of the recess and in a second position, is positioned above the bottom surface of the recess.

Description

A VESSEL

FIELD OF THE INVENTION

The present invention relates to a vessel.

BACKGROUND ART

In order to make a vessel more manoeuverable at low speed, one or more thrusters may be used at the bow and/or at the middle portion and/or at the stern of the vessel. Bow thrusters make docking easier, since they allow the captain to turn the vessel to port or starboard side, without using the main propulsion mechanism which requires some forward motion for turning. Large vessels usually have one or more tunnel thrusters built into the bow, below the water line. An impeller in the tunnel can create thrust in either direction which makes the vessel turn. Tunnel thrusters are normally driven by electric motors, but some are hydraulically powered. These bow thrusters, also known as tunnel thrusters, may allow the vessel to dock without the assistance of tugboats, saving costs of such service. There are normally 1 to 4 lateral tunnel thrusters in a prior art vessel.

Lateral thrusters in the bow requires that the vessel has a certain width in the bow so that a transverse tunnel may pass from the port side to the starboard side of the vessel, whereby the impeller is accommodated within the transverse tunnel. The transverse tunnel is provided with openings at each side of the bow of the vessel. These openings will increase the resistance of the vessel in the water which results in a worsen fuel economy of the vessel. An average resistance penalty caused by each lateral thruster opening is approximately 1 to 2% of the vessels total resistance in water. BRIEF DESCRIPTION OF THE INVENTION

An object of the present invention is to achieve an improved vessel.

The vessel according to the invention is defined in claim 1 .

The vessel comprises:

a hull having a bottom line and a bow,

at least one thruster being movable from the inside of the hull of the vessel towards the outside of the hull of the vessel and vice a versa, the at least one thruster being rotatable around a vertical axis,

a recess is arranged in the bow above the bottom line of the hull of the vessel, the recess comprising a bottom surface forming a portion of the hull of the vessel,

the at least one thruster is positioned within the recess so that in a first position, a propeller of the thruster is positioned below the bottom surface of the recess and in a second position, the propeller of the thruster is positioned above the bottom surface of the recess.

The invention eliminates the need for a transverse tunnel and thereby also the need for openings at both sides of the bow of the vessel for the transverse tunnel. The total resistance of the vessel can thus be reduced.

The invention allows the designer of the vessel to make a hull form that has an increased efficiency compared to a hull provided with one or more tunnel thrusters at the bow.

The invention makes it also possible to reduce the size and the power of the thrusters compared to a situation in which tunnel thrusters are used. The manoeuvring performance of the vessel will be better with the invention in spite of the reduced size and power of the thrusters.

The retractable thrusters may be rotated 360 degrees around a vertical axis, which means that the thrust produced by the thrusters can be directed in any desired direction. The thrusters may be used at low speeds e.g. up to 15 knots as additional propulsion devices to assist the main propulsion devices.

The retractable thrusters may in an embodiment always be kept above the baseline of the vessel i.e. even in the lower position in which the uppermost portion of the propeller of the thruster is below the water line of the vessel.

The invention makes it possible for the operator of the vessel to improve the manoeuvring capability of the vessel at low speeds when the thrusters are in the deployed position and to reduce the fuel costs of the vessel at transit when the thrusters are in the retracted position.

Tunnel thrusters can only be used at low speeds e.g. up to 15 knots. Retractable thrusters may on the other hand be used as propulsion devices also at medium speeds i.e. not only at low speeds.

BRIEF DESCRIPTION OF THE DRAWINGS

In the following the invention will be described in greater detail by means of preferred embodiments with reference to the attached drawings, in which: Figure 1 shows a portion of a vessel according to one embodiment of the invention,

Figure 2 shows a top view of figure 1 ,

Figure 3 shows a portion of a vessel according to a second embodiment of the invention,

Figure 4 shows a top view of figure 3,

Figure 5 shows a thruster arrangement in a vessel according to one embodiment of the invention.

DETAILED DESCRIPTION OF THE INVENTION

Figure 1 shows a portion of a vessel according to one embodiment of the invention and figure 2 shows a top view of figure 1 .

The figures show a portion of the bow 30 of the vessel 10. The forward direction S1 of travel of the vessel 10 is also indicated in the figure.

The bow 30 of the vessel 10 is situated upstream in relation to the aft of the vessel 10. The hull 20 of the vessel 10 has a bottom line BL and a bow 30.

The base line BL of the vessel is the line following the lowermost part of the hull of the vessel. The bilge is the lower point of the inner hull of a vessel and the base line BL follows the lower point of the outer hull of the vessel.

A recess 100 may be formed in the bow 30 of the vessel 10. The recess may be formed in the bow 30 above the bottom line BL of the hull 1 1 of the vessel 10. The recess 100 may extend upwards in the bow 30 from the bottom line BL of the hull 20 of the vessel 10. The recess 100 may form a downwards, towards sea water open space in the bow 30.

The bow 30 may comprise an upstream end portion 31 , a middle portion 32 and a downstream end portion 33. A bottom surface of the middle portion 32 of the bow 30 may form a bottom surface 1 10 of the recess 100. The bottom surface 1 10 of the recess 100 may be essentially horizontal. The bottom surface 1 10 of the recess 100 may be at a vertical distance Y10 above the bottom line BL of the hull 20 of the vessel 10.

A bottom of the downstream end portion 33 of the bow 30 may comprise an inclined surface connecting a downstream edge of the bottom surface 1 10 of the recess 100 to an upstream edge of the bottom line BL of the hull 20 of the vessel 10. Said inclined surface may form a downstream side surface 130 of the recess 100. An upper edge of the downstream side surface 130 of the recess 100 is positioned further upstream compared to a lower edge of the downstream side surface 130 of the recess 100.

A bottom surface of the upstream end portion 31 of the bow 30 may be essentially horizontal and positioned at the same vertical distance Y10 above the bottom line BL of the hull 20 of the vessel 10 as the bottom 1 10 of the recess 100. This means that the recess 100 is open towards a forward direction of travel S1 of the vessel 10.

The figures shows two water lines WL1 and WL2. The lower water line WL1 shows the water line of the vessel 10 in a situation in which the vessel 10 is unloaded. The higher water line WL2 shows the water line of the vessel 10 in a situation in which the vessel 10 is fully loaded.

The water line is the line where the hull of the vessel meets the surface of the water. The water line of an unloaded vessel is lower compared to the water line of a loaded vessel. Different water lines may be provided for a vessel depending on the environment in which the vessel is to be operated.

The recess 100 may extend in a transverse direction across the whole width of the bow 30 from the port side to the starboard side of the bow 30. The recess 100 may be open at the port and at the starboard side of the bow 30.

A number of compartments e.g. two compartments 40, 50 as shown in the figure may be positioned in the middle portion 32 of the bow 30. The compartments 40, 50 extend upwards in the vertical direction Y into the vessel 10 from the bottom of the middle portion 32 of the bow 30. Each compartment 40, 50 may comprise an opening 41 , 51 at the bottom of the middle portion 32 of the bow 30. The openings 41 , 51 are thus situated at the bottom 1 10 of the recess 100.

A first compartment 40 may be formed within an upstream portion of the middle portion 32 of the bow. A second compartment 50 may be formed within a downstream portion of the middle portion 32 of the bow 30. The two compartments 40, 50 may thus be positioned after each other in the forward direction S1 of the vessel 10.

Figure 3 shows a portion of a vessel according to a second embodiment of the invention and figure 4 shows a top view of figure 3.

This second embodiment differs from to the first embodiment shown in figure 1 in the form of the upstream end portion 31 of the bow 30. The upstream end portion 31 of the bow 30 extends in this second embodiment downwards from the bottom of the middle portion 32 of the bow 30.

The upstream end portion 31 of the bow 30 may still have a horizontal bottom surface. The bottom surface of the upstream end portion 31 of the bow 30 is in this second embodiment positioned below the bottom 1 10 of the recess 100.

An upstream edge of the middle portion 32 of the bow 30 is connected with an inclined surface to a downstream edge of the upstream end portion 31 of the bow 30. Said inclined surface may form an upstream side surface 120 of the recess 100. An upper edge of the inclined upstream side surface 120 of the recess 100 is further downstream compared to a lower edge of the inclined upstream side surface 120 of the recess 100.

The middle portion 32 and the downstream end portion 33 of the bow 30 in this second embodiment correspond to the respective middle portion 32 and the downstream end portion 33 of the bow 30 in the first embodiment.

The compartments 40, 50 in this second embodiment correspond to the compartments 40, 50 in the first embodiment.

Each of the compartments 40, 50 may comprise a thruster 60, 70. The thruster 60, 70 may be arranged to be movable in the vertical direction Y within the respective compartment 40, 50 between a first position in which a lowermost portion of the propeller 63, 73 of the thruster 60, 70 is situated essentially at or above the bottom line BL of the hull 20 of the vessel 10 and a second position in which the lowermost portion of the propeller 63, 73 of the thruster 60, 70 is positioned within the compartment 40, 50 above the opening 41 , 51 of the compartment 40, 50.

The first position of the propeller is shown below the first compartment 40. The thruster 60 in the first compartment 40 is shown in a transverse view and the thruster 70 in the second compartment 50 is shown in a longitudinal view.

The uppermost portion of the propeller 63, 73 of the thruster 60, 70 is naturally positioned below the waterline WL1 or WL2 of the vessel 10 in the first position.

Each thruster 60, 70 may comprise a frame structure 61 , 62, 71 , 72 having an upper portion 61 , 71 forming a support arm and a lower portion 62, 72 forming a casing for a propeller shaft 64, 74. A propeller 63, 73 may be positioned at an outer end of the propeller shaft 64, 74 outside an upstream end of the lower portion 62, 72. The lower portion 62, 72 of the frame structure 61 , 62, 71 , 72 has a gondola form with a first end and a second opposite end. The gondola may have at least substantially an air-foil shaped cross section, whereby the first end is formed as a rounded leading edge and the second end is formed as a sharp trailing edge. The propeller shaft 64, 74 may be rotatably supported with bearings within the lower portion 62, 72 of the frame structure 61 , 62, 71 , 72. One of the bearings may be a combined radial and axial bearing in order to transfer the axial thrust produced by the propeller 63, 73 from the propeller shaft 64, 74 to the frame structure 61 , 62, 71 , 72.

The upper portion 61 , 71 of the thruster 60, 70 may be attached to a canister 80, 90. The canister 80, 90 may be movable in the vertical direction within the compartment 40, 50. The canister 80, 90 may comprise a support beam 81 , 91 at the upper end of the canister 80, 90.

The support beam 81 , 91 of each canister 80, 90 may be attached to a lifting arrangement 82, 83, 92, 93 for moving the canister 80, 90 and thereby the thruster 60, 70 in the vertical direction Y between the first position and the second position. The lifting arrangement may comprise actuators 82, 83, 92, 93, whereby the canister 80, 90 may be suspended on the actuators 82, 83, 92, 93 from the support beam 81 , 91 . The actuators 82, 83, 92, 93 may be formed of cylinder-piston actuators. Each end of each support beam 81 , 91 may be attached to a lower end of the piston. The piston may be movable in the vertical direction Y upwards and downwards within the cylinder, whereby also the canister 80, 90 and thereby also the thruster 60, 70 may be movable in the vertical direction Y upwards and downwards within the compartment 40, 50.

Each thruster 60, 70 may be rotatably attached to the lower end of the canister 80, 90 so that the thruster 60, 70 may rotate around a respective vertical axis Y1 , Y2 of rotation. This may be arranged so that the upper end of the upper portion 61 , 71 of the frame structure 61 , 62, 71 , 72 of the thruster 60, 70 is attached to a turn wheel which is supported with a slewing bearing on the bottom portion of the canister 80, 90. One or more steering electric motors may be connected via pinions to the cogs of the turn wheel, whereby the turn wheel may be turned with said one or more steering electric motors.

The lower portion 62, 72 of the frame structure 61 , 62, 71 , 72 may further be provided with a driving electric motor for driving the propeller shaft 64, 74. The driving electric motor may be positioned horizontally in the lower portion 62, 72 of the frame structure 61 , 62, 71 , 72. The other possibility is to position the driving electric motor vertically in the lower portion 62, 72 of the frame structure 61 , 62, 71 , 72, whereby a vertical shaft would be needed between the vertical driving electric motor and the propeller shaft 64, 74. A third possibility would be to position the driving electric motor within the canister 80, 90 whereby a vertical shaft would be needed between the vertical driving electric motor and the propeller shaft 64, 74.

In the second and the third possibility, a transmission is needed between the vertical shaft and the horizontal propeller shaft 64, 74. The transmission may be formed of a first pinion attached to the vertical shaft and a second pinion attached to the horizontal propeller shaft 64, 74. The cogs on the periphery of the pinions may be in contact with each other so that the rotation of the vertical shaft also rotates the horizontal propeller shaft 64, 74.

The electric power needed in the driving electric motor may be produced within the hull 20 of the vessel 10. The electric power can be produced by a generator connected to a combustion engine. The electric power to the driving electric motor may be supplied by cables and/or bus bars running from the generator within the interior of the hull 20 of the vessel 10 to the driving electric motor. A slip ring arrangement may be needed in connection with the turn wheel in order to transfer electric power from the stationary hull 20 to the driving electric motor positioned inside the frame structure 61 , 62, 71 , 72 of the rotatable thruster 60, 70. A slip ring arrangement may not be needed if the driving electric motor is situated within the stationary canister 80, 90 or if the rotation of the thruster 60, 70 around the vertical axis Y1 , Y2 is limited.

A nozzle 65, 75 may be fixedly supported on the propulsion unit 60, 70. The nozzle 65, 75 may surround an outer perimeter of a propeller 63, 73 of the thruster 60, 70. The nozzle 65, 75 may be attached with vanes extending from an inner perimeter of the nozzle 65, 75 inwards to an outer perimeter of the lower portion 62, 72 of the frame structure 61 , 62, 71 , 72 of the thruster 60, 70. The vanes may extend in the radial direction or at an angle to the radial direction. The vanes would in the latter case be inclined in relation to the radial direction.

The nozzle 65, 75 may be annular and have the form of a cylinder or of a truncated cone with open ends. The nozzle may be rotationally symmetrical or rotationally asymmetrical. The cross section of the upper portion of the nozzle 65, 75 may be different compared to the cross section of the lower portion of the nozzle 65, 75.

The thruster 60, 70 need not necessary be provided with a nozzle 65, 75 surrounding the propeller 63, 73. The nozzle 65, 75 may in some applications be left out.

The axial centre line X-X of the propeller shaft 64, 74 may also form an axial centre line of the nozzle 65, 75. The nozzle 65, 75 surrounds an outer perimeter of the propeller 63, 73 and forms a duct with an axial flow path for water flowing through the interior of the nozzle 65, 75. The rotating propeller 63, 73 causes water to flow through the central duct from a first end of the central duct to the second end of the central duct. The thrust produced by the propeller 63, 73 is amplified by the nozzle 65, 75.

The propeller 63, 73 may be a pulling or a pushing propeller. Figure 3 shows a pushing propeller i.e. the propeller 63, 73 is situated at a backward end of the lower portion 62, 72 of the frame structure 61 , 62, 71 , 72. A pulling propeller 63, 73 would be positioned at a forward end of the lower portion 62, 72 of the frame structure 61 , 62, 71 , 72.

The centre axis X-X of the propeller shaft 64, 74 is directed in the horizontal direction in the embodiment shown in the figures. The centre axis X of the propeller shaft 64, 74 could, however, be inclined in relation to the horizontal direction. The lower portion 62, 72 of the frame structure 61 , 62, 71 , 72 of the thruster 60, 70 would thus be inclined in relation to the horizontal direction. This might in some circumstances result in hydrodynamic advantages.

The angle a between the swivel axis Y of the thruster 60, 70 and the swivel axis X-X of the propeller shaft 64, 74 may be 90 degrees. The angle a between the swivel axis Y of the thruster 60, 70 and the swivel axis X-X of the propeller shaft 64, 74 could on the other hand be less than 90 degrees or more than 90 degrees.

The opening 41 , 51 at the bottom of the compartment 40, 50 may be open or it may be provided with closing means e.g. a hatch in order to close the opening 41 , 51 when the thruster 60, 70 is in the retracted position within the hull 20 of the vessel 10. The closing means need to be movable in order to open the opening 41 , 51 at the bottom of the compartment 40, 50 when the propeller 63, 73 of the thruster 60, 70 is to be lowered below the opening 41 , 51 of the compartment 40, 50. In case there are no closing means for the opening 41 , 51 , then the form of the opening 41 , 51 may be optimized in view of minimum drag and sloshing effects inside the compartment 40, 50.

There may be 1 to 4 thrusters 60, 70 extending into the vessel 10 from the bottom 1 10 of the recess 100.

The compartments 40, 50 may be cylindrical in which case also the canisters 80, 90 are cylindrical.

The figures show embodiments in which the thruster 60, 70 move in the vertical direction Y1 , Y2 within compartments 40, 50. The thrusters 60, 70 could instead be attached to a swinging arm, whereby the movement between the first position and the second position would be through a swing movement instead of a vertical movement. There would probably be no need to accommodate the thrusters 60, 70 into compartments 40, 50 in such a solution.

The figures show embodiments in which in the first position, a lowermost portion of the propeller 63, 73 of the thruster 60, 70 is situated substantially at or above the bottom line BL of the vessel 10. The lowermost portion of the propeller 63, 73 of the thruster 60, 70 could on the other hand in the first position also be situated under the bottom line BL of the vessel 10.

The invention and its embodiments are not limited to the examples described above but may vary within the scope of the claims.

Claims

1 . A vessel comprising:

a hull (20) having a bottom line (BL) and a bow (30),

at least one thruster (60, 70) being movable from the inside of the hull (20) of the vessel (10) towards the outside of the hull (20) of the vessel (10) and vice a versa, the at least one thruster (60, 70) being rotatable around a vertical axis (Y1 , Y2),

characterized in that

a recess (100) is arranged in the bow (30) above the bottom line

(BL) of the hull (20) of the vessel (10), the recess (100) comprising a bottom surface (1 10) forming a portion of the hull (20) of the vessel (10),

the at least one thruster (60, 70) is positioned within the recess (100) so that in a first position, a propeller (63, 73) of the thruster (60, 70) is positioned below the bottom surface (1 10) of the recess (100) and in a second position, the propeller (63, 73) of the thruster (60, 70) is positioned above the bottom surface (1 10) of the recess (100).

2. The vessel according to claim 1 , characterized in that the vessel further comprises:

at least one compartment (40, 50) extending in a vertical direction

(Y) within the vessel (10) and comprising an opening (41 , 51 ) at the bottom surface (1 10) of the recess (100),

the thruster (60, 70) being situated in the compartment (40, 50), the thruster (60, 70) being movable in the vertical direction (Y) between the first position and the second position.

3. The vessel according to claim 2, characterized in that in the first position, a lowermost portion of the propeller (63, 73) of the thruster (60, 70) is situated substantially at or above the bottom line (BL) of the vessel (10) and in the second position, the lowermost portion of the propeller (63, 73) of the thruster (60, 70) is positioned within the compartment (40, 50) above the opening (41 , 51 ) of the compartment (40, 50).

4. The vessel according to any one of claims 1 -3, characterized in that the bow (30) comprises an upstream end portion (31 ), a middle portion (32) and a downstream end portion (33), a bottom surface of the middle portion (32) of the bow (30) forming the bottom surface (1 10) of the recess (100).

5. The vessel according to any one of claims 1 -4, characterized in that a bottom of the downstream end portion (33) of the bow (30) comprises an inclined surface connecting a downstream edge of the bottom surface (1 10) of the recess (100) to an upstream edge of the bottom line (BL) of the hull (20) of the vessel (10), said inclined surface forming a downstream side surface (130) of the recess (100).

6. The vessel according to claim 4 or 5, characterized in that a bottom of the upstream end portion (31 ) of the bow (30) is essentially at the same horizontal level as the bottom (1 10) of the recess (100), whereby the recess (100) is open to a forward direction of travel (S1 ) of the vessel (10).

7. The vessel according to claim 4 or 5, characterized in that the upstream end portion (31 ) of the bow (30) extends downwards from the bottom (1 10) of the recess (100), whereby the recess (100) is at least partly closed to a forward direction of travel (S1 ) of the vessel (10).

8. The vessel according to claim 7, characterized in that the upstream end portion (31 ) of the bow (30) comprises an inclined surface connecting an upstream edge of the bottom surface (1 10) of the recess (100) to a downstream edge of a bottom of the upstream end portion (31 ) of the bow (30), said inclined surface forming an upstream side surface (120) of the recess (100).

9. The vessel according to claim 8, characterized in that a bottom of the upstream end portion (31 ) of the bow (30) is essentially horizontal and situated at a horizontal level below the bottom (1 10) of the recess (100).

10. The vessel according to any one of claims 1 to 9, characterized in that the recess (100) extends in a transverse direction across the whole width of the bow (30) from a port side to a starboard side of the bow (30).

1 1 . The vessel according to any one of claims 1 to 10, characterized in that the recess (100) is open at a port and at a starboard side of the bow (30).

12. The vessel according to any one of claims 2 to 1 1 , characterized in that the thruster (60, 70) comprises a frame structure (61 , 62, 71 , 72) having an upper portion (61 , 71 ) forming a support arm and a lower portion (62, 72) forming a casing for a propeller shaft (64, 74), a propeller (63, 73) being positioned at an outer end of the propeller shaft (64, 74) outside the lower portion (62, 72) of the frame structure (61 , 62, 71 , 72).

13. The vessel according to claim 12, characterized in that the upper portion (61 , 71 ) of the thruster (60, 70) is attached to a canister (80, 90), said canister (80, 90) being vertically (Y) movable within the compartment (40, 50).

14. The vessel according to claim 13, characterized in that the thruster (60, 70) is rotatably attached to the canister (80, 90) so that the thruster (60, 70) may rotate around a vertical axis (Y1 , Y2) of rotation.

15. The vessel according to claim 13 or 14, characterized in that the canister (80, 90) is attached to a lifting arrangement (82, 83, 92, 93) for moving the canister (80, 90) and thereby the thruster (60, 70) in the vertical direction (Y) between the first position and the second position.