SHIP EQUIPPED WITH MAIN PROPELLER AND ADDITIONAL PROPELLER AND HYBRID OPERATING METHOD THEREFOR

Abstract

[Problems]

To reduce the fuel consumption without impairing operational safety of the ship

[Solution to Problem]

A ship 10 configured to obtain propelling force by driving a main propeller 11 with a main engine 12 is provided with an additional propeller 20 and a driving unit therefore. The additional propeller 20 is disposed at a ship bottom or at a rising section of the ship bottom, in a position different from the main propeller 11. Further, the output of the driving unit of the additional propeller 20 is 25% or less than the output of the driving unit of the main engine, and the operating condition can be selectable between regular operating condition in which propelling force is obtained by driving the main propeller 11 and die other operating condition in that propelling force is obtained by driving the additional propeller 20.

Claims

1. A ship configured to obtain propelling force by driving a main propeller with a main engine, and provided with an additional propeller and a driving unit for the additional propeller, wherein one or a plurality of the additional propellers is disposed at a ship bottom or at a rising section of the ship bottom, in a position different from where the main propeller is disposed, and operating condition is selectable between regular operating condition in which propelling force is obtained by driving the main propeller and the other operating condition in which propelling force is obtained by driving the additional propeller.

2. The ship according to claim 1, wherein the additional propeller is a duct propeller.

3. The ship according to claim 2, wherein an operational position of the duct propeller is selectable between a state of being assembled at the outside of the ship and the other state of being retracted to the inside of the ship.

4. The ship according to claim 2, wherein the duct propeller is provided at a stern area.

5. The ship according to claim 2, wherein the duct propeller is provided at a bow area.

6. The ship according claim 2, wherein the duct propeller is provided at an intermediate area in the ship length direction.

7. The ship according to claim 2, wherein the duct propeller is rotatable around a vertical shaft line.

8. A method far operating a ship configured to obtain propelling force by driving a main propeller with a main engine, and provided with an additional propeller and a driving unit for the additional propeller, wherein the additional propeller is disposed at a ship bottom or at a rising section of the ship bottom, in a position different from where the main propeller is disposed, and the ship is propelled by driving the main propeller in a load condition, and the ship is propelled by driving the additional propeller in an unload condition.

9. The method for operating a ship according to claim 8, wherein the additional propeller is a duct propeller, and the duct propeller is provided at a bow area, and the ship is propelled in a stern direction by driving the duct propeller in an unload condition.

10. The method for operating a ship according claim 9, wherein the duct propeller is retractable to the inside of the ship, and the ship is propelled in the stern direction by driving the duct propeller after extracting the duct propeller from the inside to the outside of the ship so as to be assembled therein an unload condition.

11. The method for operating a ship according to claim 9, wherein the main propeller is partially or entirely disposed on a draft line when the duct propeller is driven in the unload condition.

12. The method for operation a ship according to claim 8, wherein an air blowing section is provided on an upper portion of a duct of the additional propeller to blow out air from the air blowing section, and the ship navigates generating a flow of bubbles at the ship bottom.

Description

BRIEF DESCRIPTION OR DRAWINGS

[0046] FIG. 1 is a schematic front view of a ship in a load condition according to the present invention;

[0047] FIG. 2 is a front view of an exemplary duct propeller;

[0048] FIG. 3 is a schematic front view of the ship according to the present invention while operating in an unload condition; and

[0049] FIG. 4 is a perspective view of another example of the duct propeller according to the present invention.

DESCRIPTION OF EMBODIMENTS

[0050] An embodiment of the present invention will be described with reference to the attached drawings.

[0051] FIG. 1 is a schematic front view of a ship according to the present invention, for example, a commercial ship 10 loaded with cargo, such as a cargo ship. The commercial ship 10 obtains propelling force by driving a main propeller 11 by a main engine (propulsion engine) 12 such as a diesel engine. The reference sign 14A represents a water line in an unload condition, indicating a state of trim by head in which the water line gradually becomes higher in a bow direction and intersects with a ship bottom line in a stern direction. In FIG. 3, the reference sign 14B represents a water line, indicating a state of trim by the stern which is a reverse state of the above state.

[0052] As is referenced in FIG. 2, the ship is provided with an additional propeller 20 including a driving unit 22 therefore and a duct propeller 21.

[0053] This additional propeller 20 is disposed to a position different from the main propeller 11, more specifically, in a bow area, a stern area, or an intermediate position an a ship bottom or a rising section of the ship bottom. The case of disposing the additional propeller at the stern position is indicated by the reference sign 20A, and the case of disposing the same at the intermediate position is indicated by the reference sign 20B.

[0054] Additionally, a bridge 13 is provided on the stern side, and a window 13A is formed so as to monitor not only the bow-side direction but also the stern-side direction.

[0055] The output of the driving unit 22 of the additional propeller 20 is small, which is 25% or less than the output of a driving unit of the main engine 12.

[0056] Further, operating condition is selectable between regular operating condition in which propelling force is obtained by driving the main propeller 11 and the other operating condition in which propelling force is obtained by driving the additional propeller 20.

[0057] Explaining an example of the additional propeller 20, an electric motor or a hydraulic motor may be used as the driving unit 22, and further, if necessary, may be connected with the main engine (propulsion engine) 12 so as to obtain drive power.

[0058] The duct propeller 21 that includes a duct 21A around thereof is configured to be rotated when rotational drive force of an output shaft 23 by the driving unit 22 is transmitted so a vertical shaft 25 through a pair of bevel gears 24 and then transmitted, as rotational force of a propeller drive shaft 27, through a pair of bevel gears 26 provided at the vertical shaft 25.

[0059] On the other hand, the duct propeller 21 is configured to be rotatable around the vertical shaft 25 when rotational drive force of a transmission shaft 28 by the driving unit 22 is transmitted to a driving small gear 29 and a large gear 30 engaged therewith.

[0060] Further, a device including the duct propeller 21 disposed below a ship bottom 10A is assembled at the outside of the ship bottom 10A as illustrated in FIG. 2, but preferably, the device is configured to be retractable to the inside of the ship because such assembly of the duct propeller at the outside is to be an obstacle during normal navigation. The reference sign 10B indicates a shielding member that shuts after the device is retracted to the inside of the ship.

[0061] With this configuration, when cargo R is loaded, the ship is operated by driving the main propeller 11 with the main engine 12 in a state of draft close to designed load draft as illustrated in FIG. 1.

[0062] After the cargo is unloaded, especially in a day of calm weather or in a quiet sea, the ship is operated with the small additional propeller 20, keeping the draft line low as illustrated in FIG. 3 because there is little necessity to secure stability of the ship too severely at the time of navigating the ship. In this case, as indicated by an outlined arrow in FIG. 3, a moving direction of the ship can be suitably selected, and the bow and the stern are monitored by the bridge 13 depending on the moving direction of the ship.

[0063] As a result, by lowering the draft line, apparent displacement is decreased and the contact area with the water of the shell is reduced. Further, a waterplane area coefficient can be improved and significant reducing effects of fuel consumption can be obtained.

[0064] Moreover, since the small additional propeller 20 is driven, small output from the driving unit 22 is enough, and the ship can be operated with the output of 35% or less, especially 25% or less, and best of all, about 10% to 5% of the output of the driving unit in the main engine 11. From this viewpoint, significant reducing effects of fuel consumption can be obtained. In a day of calm weather (when Beaufort scale is 0 to 3), travel speed of approximately 5 to 10 knots is enough.

[0065] In the case where the ship leaves a port after unloading the cargo R and then shifts to the regular navigation, the ship navigates by driving the additional propeller mainly or by driving main propeller 11 or in a combined manner while keeping the lower draft.

[0066] Further, in the case of bad weather, ballast water BW (reserve space for the ballast water is not illustrated) is filled even in an unload condition. This enables the ship to travel in a stabilized state by means of the small additional propeller 20 or the main propeller 11.

[0067] When the duct propeller 21 is rotatable around a vertical shaft line, propelling in the stern direction can be achieved by driving the duct propeller 21 as illustrated in FIG. 3 in a required operating condition.

[0068] In the case where the duct propeller 21 is rotatable around the vertical shaft 25 (vertical shaft line), when the additional propeller and the main propeller are operated in a combined manner, a steering system can be additionally provided by suitably rotating the additional propeller around the vertical shaft line, and maneuverability (directional property) can be improved. Further, when the ship is docked at a port, the duct propeller is oriented sideways so as to be utilized as a slide thruster.

[0069] Further, a propeller idling prevention device 11A for preventing the main propeller 11 from rotating may be provided so that the duct propeller 21 is driven to propel the ship in the bow direction.

[0070] If necessary, the duct propeller 21 may be provided on the right and left sides by setting a center line of the ship as a boundary. The duct propellers 21, 21 on the right and left sides rotate around the vertical shaft line, thereby improving the maneuverability. Further, when the propeller is utilized as the slide thruster, the ship can be more easily docked at the port.

[0071] On the other hand, the additional propeller 20 preferably includes an air blowing section 21B formed at the duct 21A of the duct propeller 21 as illustrated in FIG. 4, and the ship can navigates blowing air from the air blowing section 21B and generating a flow of bubbles B at the ship bottom.

[0072] As the ship navigates blowing the air from the air blowing section 21B and generating the flow of bubbles B at the ship bottom, friction of a hull can be reduced by the generated bubbles B. Preferably, the air blowing section 21B is provided on an upper side of the duct 21A of the duct propeller 21 at the additional propeller 20 according to the present invention, thereby reducing friction of the hull (particularly, at the ship bottom) and achieving economic operation.

INDUSTRIAL APPLICABILITY

[0073] The present invention is applicable to a standard cargo ship, a container ship, a tanker, an LNG carrier, a car carrier, a bulk carrier, a cargo-passenger ship, and so on.

REFERENCE SIGNS LIST

[0074] 10 - - - Ship [0075] 11 - - - Regularly Used Propeller (Main Propeller) [0076] 12 - - - Main Engine (Propulsion Engine: Driving Unit) [0077] 20 - - - Additional Propeller [0078] 21 - - - Duct Propeller [0079] 22 - - - Driving Unit