Propulsion unit for maritime vessel including a nozzle exhibiting an exchangable leading edge on the inlet of the nozzle

1. A propulsion unit ( 11 ) for propulsion and maneuvering of a maritime vessel having a hull, comprising:

a nozzle ( 12 ) provided with a sectioned leading edge ( 21 ) on an inlet of the nozzle ( 12 ), the leading edge ( 21 ) is formed by sections ( 21 a ) of a low-weight non-metallic material and a front ring ( 30 ), the front ring ( 30 ) is arranged between a main part of the nozzle and the sectioned leading edge ( 21 ) and provides a fastening point for the sections ( 21 a ) of the leading edge ( 21 );

a propeller section ( 13 , 13 a ) rotatably attached to the nozzle ( 12 ) about a hub ( 14 ) by means of stays ( 15 , 16 ) or by periphery supports, the propeller section ( 13 , 13 a ) is electrically or hydraulically driven; and

a fastening device ( 17 ) attached to the hull of the vessel or a steering device arranged for steering or moving the propulsion unit ( 11 ).

2. The propulsion unit of claim 1 , wherein the stays ( 15 ) in front of the propeller section ( 13 ) are integrated into the front ring ( 30 ).

3. The propulsion unit of claim 2 , wherein the stays ( 15 ) are attached to the front ring ( 30 ) by means of casting, welding, or bolts and extend from the periphery of the front ring ( 30 ) towards the center of the front ring ( 30 ) where the stays are fixed to the hub ( 14 ).

4. The propulsion unit of claim 1 , wherein the front ring ( 30 ) exhibits an inclined profile which is adapted to an inner surface of the nozzle ( 12 ) for forming a joint between the leading edge ( 21 ) and inner surface of the nozzle ( 12 ) positioned close to the propeller section ( 13 ), and for forming a joint between the leading edge ( 21 ) and nozzle ( 12 ) on outside thereof.

5. The propulsion unit of claim 1 , wherein the front ring ( 30 ) is arranged to support peripheral bearings for the propeller section ( 30 ) and to seal for oil surrounding motor inside the nozzle ( 12 ).

6. The propulsion unit of claims 1 , wherein the nozzle ( 12 ) exhibits a curved leading edge ( 21 ) such that an axial length of the nozzle ( 12 ) is longest at an upper part of the nozzle ( 12 ) and decreases towards a lower part of the nozzle ( 12 ).

7. The propulsion unit of claim 6 , wherein the lower part of the nozzle ( 12 ) has a shorter length than the upper part of the nozzle.

8. The propulsion unit of claims 1 , wherein the nozzle ( 12 ) exhibits a curved leading edge ( 21 ), such that an axial length of the nozzle ( 12 ) extends with decreasing length from an upper part to outermost points of a horizontal central axis through the nozzle ( 12 ) and with increasing length from the outermost points of the horizontal axis through the nozzle ( 12 ) to a lower part of the nozzle ( 12 ).

9. The propulsion unit of claims 1 , wherein the nozzle ( 12 ) includes a leading edge ( 21 ) having a tangentially varying design.

10. The propulsion unit of claim 1 , wherein the sections ( 21 a ) are provided with fastening means for attachment to the front ring ( 30 ).

11. The propulsion unit of claim 1 , wherein the sections ( 21 a ) are provided with fastening means for mutual attachment to one another.

12. The propulsion unit of claim 1 , wherein the fastening device ( 17 ) is formed by one or two stems ( 18 , 18 a - b ) ending in a fixing flange ( 19 ), the stems ( 18 , 18 a - b ) are wing or rudder-shaped such that they are hydrodynamically optimal to avoid unnecessary turbulence, noise, or vibrations.

13. The propulsion unit of claim 12 , wherein the two stems ( 18 a - b ) extend in parallel or laterally reversed from an upper part of the nozzle ( 12 ) of the propulsion unit, the stems ( 18 a - b ) and a fixing flange ( 19 ) form an opening ( 20 ) which provides the propulsion unit ( 11 ) with improved hydrodynamic performance.

14. A propulsion unit ( 11 ) for propulsion and maneuvering of a maritime vessel having a hull, comprising:

a nozzle ( 12 ) provided with a sectioned leading edge ( 21 ) on an inlet of the nozzle ( 12 ), the leading edge ( 21 ) is formed by sections ( 21 a ) of a low-weight non-metallic material and at least one section ( 21 a ) of metal;

a propeller section ( 13 , 13 a ) rotatably attached to the nozzle ( 12 ) about a hub ( 14 ) by means of stays ( 15 , 16 ), the propeller section ( 13 , 13 a ) is electrically or hydraulically driven, the stays ( 15 ) extend from the periphery of the leading edge ( 21 ) towards a center of the leading edge ( 21 ) and are connected to the hub ( 14 ) at the opposite end of the stays ( 15 ); and

a fastening device ( 17 ) attached to the hull of the vessel or a steering device arranged for steering or moving the propulsion unit ( 11 );

wherein at least one section ( 21 a ) of metal is integrated with said stays ( 15 ) in front of said propeller section ( 13 ).

15. The propulsion unit of claims 14 , wherein the nozzle ( 12 ) exhibits a curved leading edge ( 21 ) such that an axial length of the nozzle ( 12 ) is longest at an upper part of the nozzle ( 12 ) and decreases towards a lower part of the nozzle ( 12 ).

16. The propulsion unit of claims 14 , wherein the nozzle ( 12 ) exhibits a curved leading edge ( 21 ), such that an axial length of the nozzle ( 12 ) extends with decreasing length from an upper part to outermost points of a horizontal central axis through the nozzle ( 12 ) and with increasing length from the outermost points of the horizontal axis through the nozzle ( 12 ) to a lower part of the nozzle ( 12 ).

17. The propulsion unit of claims 14 , wherein the nozzle ( 12 ) includes a leading edge ( 21 ) having a tangentially varying design.

18. The propulsion unit of claim 14 , wherein the sections ( 21 a ) are provided with fastening means for mutual attachment to one another.

19. The propulsion unit of claim 14 , wherein the fastening device ( 17 ) is formed by one or two stems ( 18 , 18 a - b ) ending in a fixing flange ( 19 ), the stems ( 18 , 18 a - b ) are wing or rudder-shaped such that they are hydrodynamically optimal to avoid unnecessary turbulence, noise, or vibrations.

20. The propulsion unit of claim 14 , wherein the sections ( 21 a ) are provided with fastening means for attachment to the nozzle ( 12 ).