Grid for tunnel thrusters

Abstract

To provide a grid for a tunnel type thruster that enables reducing resistance against underwater movement and increasing thrust of the tunnel type thruster.SOLUTION: There is provided a grid (100) for a tunnel type thruster (200). The grid (100) includes: a plurality of first radially extending bars (101) arranged at angle intervals from each other; and a plurality of first connection bars (102). Therein each of the first connection bars (102) are connected in between adjacent first bars (101) extending radially.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to a grid for a tunnel thruster as described in the preamble of the appended independent claims. The present invention also relates to a tunnel thruster and a ship in which such a grid is incorporated.

Background Art

[0002] A tunnel thruster, also known as a transverse thruster or a steering thruster, is widely used in ships such as boats and vessels. A tunnel thruster, which is usually installed in the bow or stern of a ship below the waterline, provides a lateral thrust that supports the ship's steering, mooring, position holding, and dynamic position adjustment.

[0003] An exemplary tunnel thruster includes a tunnel section that is open at both ends. A propeller is installed inside the tunnel section and is rotated by a motor to generate thrust in either direction.

Summary of the Invention

Problems to be Solved by the Invention

[0004] A known problem associated with tunnel thrusters is an increase in the resistance to the movement of the ship in the water. A known solution to this problem is to provide grids including bars arranged perpendicular to the direction of movement of the ship at both ends (openings) of the tunnel section. Although these grids reduce the resistance to the movement of the ship in the water, they also cause a problem in the form of a reduction in the thrust of the tunnel thruster. The thrust is reduced due to the turbulent resistance generated by the bars of the grid.

[0005] The main object of the present invention is to reduce or eliminate the problems of the prior art described above.

[0006] An object of the present invention is to provide a grid for tunnel thrusters. More specifically, an object of the present invention is to provide a grid for tunnel thrusters that reduces resistance to movement underwater and enables an increase in the thrust of the tunnel thruster. It is also an object of the present invention to provide a reliable and durable grid. A further object of the present invention is to provide a grid that generates less noise and vibration. Yet another object of the present invention is to provide a grid that facilitates installation of tunnel thrusters in tunnel sections.

[0007] Another objective of the present invention is to provide a tunnel-type thruster that has low resistance to movement underwater and generates high thrust. A further objective of the present invention is to provide a ship that has low resistance to movement underwater and high thrust.

[0008] To achieve the above objectives, the grid according to the present invention is characterized by the features presented in the appended independent claims. Advantageous embodiments of the present invention are described in the dependent claims. [Means for solving the problem]

[0009] The grid for a tunnel thruster according to the present invention includes a plurality of first radially extending bars arranged at angular intervals from one another, and a plurality of first connecting bars, each of which is connected between adjacent first radially extending bars.

[0010] The grid of the present invention is intended for use in a tunnel thruster that can be installed on the hull of a vessel such as a ship or boat to provide lateral thrust. The tunnel thruster is preferably installed at the bow or stern of the vessel. The tunnel thruster includes a tunnel compartment and a propeller located inside the tunnel compartment that generates thrust in either direction. The grid is preferably located inside the tunnel compartment, near the end (opening) of the tunnel compartment. The grid is preferably sized such that the first radially extending bars can connect to the wall of the tunnel compartment.

[0011] The size and shape of the grid can vary depending on the application. The grid may be substantially circular and have dimensions that fit inside a tunnel section having an essentially circular cross-section. The grid may be substantially flat or planar, but in some embodiments it may be slightly curved.

[0012] The first radially extending bars of the grid are arranged at angular intervals from one another. The angles between adjacent first radially extending bars may be the same or different. It is also possible to arrange the first radially extending bars such that the angles between adjacent first radially extending bars have possible values, for example, 2, 3, 4, or 5.

[0013] The purpose of the first radially extending bar is to convert the rotating flow generated by the tunnel thruster's propeller into an axial (straight) flow. This improves the thrust of the tunnel thruster.

[0014] The first radially extending bars are preferably substantially straight, but in some embodiments, the first radially extending bars may be curved in one or more directions. The first radially extending bars may also be configured to be twisted along their length. The length of the first radially extending bars can be, for example, 0.1 to 5 m, preferably 0.5 to 4 m, and more preferably 0.5 to 2.5 m. It is preferable that the lengths of the first radially extending bars are substantially the same. The first radially extending bars are preferably made of stainless steel.

[0015] The number of first radially extending bars can vary depending on the application. The number of first radially extending bars is, for example, 4 to 12, preferably 5, 7, 9, or 11. It is preferable that the number of first radially extending bars and the number of propeller blades are different in such a way that they cannot be divided evenly.

[0016] The first connecting bars of the grid are connected between adjacent first radially extending bars. Each of the first connecting bars is connected between two adjacent first radially extending bars, with one end of the first connecting bar connected to one first radially extending bar and the other end of the first connecting bar connected to the other first radially extending bar. The first connecting bars can be connected to the first radially extending bars, for example, by welding or by using connecting means such as bolts. Preferably, each of the first radially extending bars is connected to an adjacent first radially extending bar by a first connecting bar. In this case, the number of first connecting bars is the same as the number of first radially extending bars.

[0017] The purpose of the first connecting bar is to reduce resistance to movement in water. They also improve the rigidity of the grid.

[0018] The first connecting bars may be substantially straight or curved in one or more directions. The first connecting bars may be curved and arranged in a grid so that they together form a circle. The length of the first connecting bars is, for example, 0.1 to 2 m, preferably 0.5 to 1.5 m, more preferably 0.5 to 1 m. It is preferable that the lengths of the first connecting bars are substantially the same. It is preferable that the first connecting bars are made of stainless steel.

[0019] The number of first connecting bars may vary depending on the application. The number of first connecting bars is, for example, 4 to 12, preferably 5, 7, 9, or 11. It is preferable that the number of first connecting bars is the same as the number of first radially extending bars.

[0020] An advantage of the grid according to the present invention is that it reduces resistance to movement underwater and increases the thrust of the tunnel thruster. Another advantage of the grid according to the present invention is that it is reliable and durable. Yet another advantage of the grid according to the present invention is that it produces less noise and vibration. Yet another advantage of the grid according to the present invention is that it can be easily installed in the tunnel section of a tunnel thruster. Yet another advantage of the grid according to the present invention is that it protects the propeller in the tunnel section to prevent objects from entering the tunnel section of the tunnel thruster.

[0021] According to one embodiment of the present invention, the first radially extending bars are flat bars, each of which has a rounded or chamfered front end. The entire length or part of the length of the front end may be rounded or chamfered. The flat bars are arranged in a grid such that their planes are perpendicular to the plane of the grid. The grid is assumed to be arranged in relation to the end of the tunnel section of a tunnel-type thruster such that the front ends of the flat bars face propellers located inside the tunnel section. The rear ends of the flat bars may also be rounded or chamfered. The front and rear ends are the longitudinal ends of the flat bars. The length of the flat bars is, for example, 0.1 to 5 m, preferably 0.5 to 4 m, more preferably 0.5 to 2.5 m. The width of the flat bars is, for example, 5 to 50 cm, preferably 10 to 30 cm. The thickness of the flat bars is, for example, 0.1 to 5 cm, preferably 1 to 2 cm. The advantage of a rounded or chamfered front end is that it improves the thrust of a tunnel thruster. Another advantage of a rounded or chamfered front end is that it reduces noise and vibration.

[0022] According to one embodiment of the present invention, the first radially extending bars are flat bars, and each of the flat bars is bent laterally. Preferably, the flat bars are bent such that at least the front end of the flat bar is bent. The bending radius may be, for example, 1 to 10 cm. The advantage of bending is to improve the thrust of the tunnel thruster. Another advantage of bending is to reduce noise and vibration.

[0023] According to one embodiment of the present invention, each of the first radially extending bars is connected to an adjacent first radially extending bar by a first connecting bar. In this case, the number of first connecting bars in the grid is the same as the number of first radially extending bars. The advantage of connecting the first radially extending bars to adjacent first radially extending bars by first connecting bars is that it reduces resistance to movement in water and increases the rigidity of the grid.

[0024] According to an embodiment of the present invention, the first connection bars are connected so as to be at the same distance from the center of the grid. The center of the grid means a point where the first ends of the first radially extending bars are attached to each other or a point where the extension lines of the first radially extending bars intersect. The distance of the first connection bars from the center of the grid can be, for example, 0.1 to 2 m, preferably 0.5 to 1.5 m, more preferably 0.5 to 1 m. The first connection bars can be curved so that they together form a circle. The advantage of arranging the first connection bars at the same distance from the center of the grid is to reduce the resistance to movement in water and increase the rigidity of the grid.

[0025] According to an embodiment of the present invention, the first ends of the first radially extending bars are connected to each other. The first ends of the first radially extending bars are connected to each other at the center of the grid. The advantage of connecting the first ends of the first radially extending bars together is to suppress the pressure drop across the grid.

[0026] According to an embodiment of the present invention, the grid includes a central portion to which the first ends of the first radially extending bars are connected. The central portion can be, for example, a disk or a ring. The diameter of the central portion is preferably smaller than the diameter of the propeller hub. The advantage of the central portion is to facilitate the optimization of the minimum area covering the opening of the tunnel section. Also, it facilitates the manufacture of the grid.

[0027] According to an embodiment of the present invention, the grid includes a plurality of second connection bars, and each of the second connection bars is connected between adjacent first radially extending bars such that the second connection bar is farther from the center of the grid than the first connection bar.

[0028] The second connecting bar of the grid is connected between adjacent first radially extending bars. Each of the second connecting bars is connected between two adjacent first radially extending bars, one end of the second connecting bar being connected to one first radially extending bar and the other end of the second connecting bar being connected to the other first radially extending bar. The second connecting bar can be connected to the first radially extending bar, for example, by welding or by using connecting means such as bolts. It is preferable that each of the first radially extending bars is connected to an adjacent first radially extending bar by a second connecting bar. In this case, the number of the second connecting bars is the same as the number of the first radially extending bars.

[0029] The second connecting bars may be substantially straight or curved in one or more directions. The second connecting bars may be curved so that they together form a circle and be arranged in the grid. The length of the second connecting bar can be, for example, 0.3 to 3 m, preferably 0.6 to 1.7 m, more preferably 0.7 to 1.2 m. It is preferable that the second connecting bars have substantially the same length. The second connecting bars are preferably made of stainless steel.

[0030] The number of the second connecting bars can vary according to the application. The number of the second connecting bars is, for example, 4 to 12, preferably 5, 7, 9 or 11. It is preferable that the number of the second connecting bars is the same as the number of the first radially extending bars.

[0031] The advantage of the second connecting bar is to further reduce the resistance to movement in water and increase the rigidity of the grid.

[0032] According to one embodiment of the present invention, the second connecting bars are connected at the same distance from the center of the grid. The distance of the second connecting bars from the center of the grid may be, for example, 0.3 to 3 m, preferably 0.6 to 1.7 m, and more preferably 0.7 to 1.2 m. The second connecting bars can be curved so that they together form a circle. The advantage of arranging the second connecting bars at the same distance from the center of the grid is that it reduces resistance to movement in water and increases the rigidity of the grid.

[0033] According to one embodiment of the present invention, the grid includes a plurality of second radially extending bars arranged at angular intervals from each other, each of the second radially extending bars being connected between one first connecting bar and one second connecting bar. Each of the second radially extending bars is connected such that one end of the second radially extending bar is connected to the first connecting bar and the other end of the second radially extending bar is connected to the second connecting bar. The second radially extending bars can be connected to the first and second connecting bars, for example, by welding or by using connecting means such as bolts. The second radially extending bars are arranged radially between the first radially extending bars. Preferably, the second radially extending bars are arranged such that their extensions intersect at the center of the grid. The second radially extending bars may have dimensions such that their ends can be connected to the walls of the tunnel section of a tunnel-type thruster.

[0034] The angles between adjacent second radially extending bars may be the same or different. It is also possible to arrange the second radially extending bars such that the angles between adjacent second radially extending bars have possible values, for example, 2, 3, 4, or 5.

[0035] In some embodiments, the second radially extending bars are preferably substantially straight, but in some embodiments, the second radially extending bars may be curved in one or more directions. The second radially extending bars may also be configured to be twisted along their length. The length of the second radially extending bars can be, for example, 0.1 to 3 m, preferably 0.5 to 2 m, and more preferably 0.5 to 1.2 m. It is preferable that the lengths of the second radially extending bars are substantially the same. The second radially extending bars are preferably made of stainless steel.

[0036] The number of second radially extending bars can vary depending on the application. The number of second radially extending bars is, for example, 4 to 12, preferably 5, 7, 9, or 11. It is preferable that the number of second radially extending bars is the same as the number of first radially extending bars.

[0037] The second advantage of radially extending bars is that they improve the thrust of the tunnel thruster by converting the swirling flow generated by the tunnel thruster's propeller into an axial (straight) flow.

[0038] According to one embodiment of the present invention, the second radially extending bars are flat bars, each of which has a rounded or chamfered front end. The entire length or part of the length of the front end may be rounded or chamfered. The flat bars are arranged in a grid such that their planes are perpendicular to the plane of the grid. The grid is assumed to be arranged in relation to the end of the tunnel section of a tunnel-type thruster such that the front ends of the flat bars face propellers located inside the tunnel section. The rear ends of the flat bars may also be rounded or chamfered. The front and rear ends are the longitudinal ends of the flat bars. The length of the flat bars is, for example, 0.1 to 3 m, preferably 0.5 to 2 m, more preferably 0.5 to 1.2 m. The width of the flat bars is, for example, 5 to 50 cm, preferably 10 to 30 cm. The thickness of the flat bars is, for example, 0.1 to 5 cm, preferably 1 to 2 cm. The advantage of a rounded or chamfered front end is that it improves the thrust of a tunnel thruster. Another advantage of a rounded or chamfered front end is that it reduces noise and vibration.

[0039] According to one embodiment of the present invention, the second radially extending bar is a flat bar, and each of the flat bars is bent laterally. Preferably, the flat bars are bent such that at least the front end of the flat bar is bent. The bending radius may be, for example, 1 to 10 cm. The advantage of bending is to improve the thrust of the tunnel thruster. Another advantage of bending is to reduce noise and vibration.

[0040] According to one embodiment of the present invention, the first and / or second radially extending bars and the first and / or second connecting bars are flat bars. The width of the radially extending bars and / or connecting bars may be, for example, 5 to 50 cm, preferably 10 to 30 cm. The thickness of the radially extending bars and / or connecting bars may be, for example, 0.1 to 5 cm, preferably 1 to 2 cm.

[0041] According to one embodiment of the present invention, the number of first radially extending bars and / or second radially extending bars is 4 to 12. Preferably, the number of first radially extending bars and / or second radially extending bars is 5, 7, 9, or 11.

[0042] The present invention also relates to tunnel thrusters. The tunnel thruster according to the present invention includes a tunnel section, a propeller disposed inside the tunnel section, and a grid according to the present invention disposed in relation to the end of the tunnel section.

[0043] The tunnel section is tubular, with open ends. The length of the tunnel section may be, for example, 1 to 4 m, 4 to 10 m, or 10 to 20 m. The tunnel section preferably has a round cross-section. The diameter of the tunnel section may be, for example, 1 to 4 m.

[0044] The propeller may be a variable-pitch (CP) propeller or a fixed-pitch (FP) propeller. The propeller can be driven by a motor integrated into the tunnel section, or by a separately mounted motor located outside the tunnel section. The motor can rotate the propeller to generate thrust in either direction.

[0045] The grid is preferably positioned inside the tunnel section, near the ends (openings) of the tunnel section. The grid is preferably sized such that the first radially extending bars can connect to the walls of the tunnel section. It is preferable that the grid according to the present invention is provided at both ends (openings) of the tunnel section.

[0046] The tunnel thruster according to the present invention can be installed on the hull of a vessel such as a ship or boat to provide lateral thrust. The tunnel thruster is preferably installed below the waterline at the bow or stern. The tunnel thruster can be used for maneuvering, mooring, positioning, and dynamic position adjustment of the vessel.

[0047] The advantage of the tunnel-type thruster according to the present invention is that it has low resistance to movement in water and generates a large thrust.

[0048] According to one embodiment of the present invention, the grid is positioned inside the tunnel section at a distance of at least 10 mm from the edge of the tunnel section. It has been found that by positioning the grid at a distance of at least 10 mm from the edge (opening) of the tunnel section, resistance to movement in water is significantly reduced.

[0049] According to one embodiment of the present invention, the first radially extending bar is connected to the tunnel section. The first radially extending bar can be connected to the wall of the tunnel section, for example, by welding or by using connecting means such as bolts.

[0050] According to one embodiment of the present invention, the number of first radially extending bars and / or second radially extending bars is different from the number of propeller blades. Preferably, the number of first radially extending bars and / or second radially extending bars is different from the number of propeller blades in such a way that these numbers are not divisible. The advantage of this is to reduce the mechanical resonance provided by the propeller and grid.

[0051] The present invention also relates to ships. A ship according to the present invention includes a tunnel thruster according to the present invention installed on the hull of the ship. The tunnel thruster is preferably installed below the waterline at the bow or stern. The tunnel thruster provides lateral thrust to support the maneuvering, mooring, positioning, and dynamic position adjustment of the ship. The ship may be a vessel or a boat. The ship may include two or more tunnel thrusters, for example, two, three, or four tunnel thrusters. The ship may include one to four tunnel thrusters installed at the bow and / or stern of the ship.

[0052] The advantages of the vessel according to the present invention are that it has low resistance to movement in water and high thrust.

[0053] The exemplary embodiments of the invention presented herein should not be construed as limiting the applicability of the appended claims. In this specification, the verb “includes” is used as an open limitation that does not exclude the existence of features not described. The features described in the dependent claims may be freely combined with each other unless otherwise expressly stated.

[0054] The exemplary embodiments presented herein and their advantages, not necessarily separately mentioned, relate to grids, tunnel thrusters, and ships according to the present invention in applicable parts. [Brief explanation of the drawing]

[0055] [Figure 1] Figure 1 shows a grid according to the first embodiment of the present invention. [Figure 2] Figure 2 shows a grid according to a second embodiment of the present invention. [Figure 3] Figure 3 shows a grid according to a third embodiment of the present invention. [Figure 4] Figure 4 shows a grid according to a fourth embodiment of the present invention. [Figure 5] Figure 5 shows a grid according to the fifth embodiment of the present invention. [Figure 6] Figure 6 shows a tunnel-type thruster according to one embodiment of the present invention. [Figure 7] Figures 7A to 7E show cross-sections of first and second radially extending bars. [Modes for carrying out the invention]

[0056] In different embodiments, the same or similar reference numerals are used for the same or similar components.

[0057] Figure 1 shows a grid according to a first embodiment of the present invention. The grid 100 includes first radially extending bars 101 arranged at angular intervals from each other. The first ends of the first radially extending bars 101 are connected to each other at the center of the grid 100. The second ends of the first radially extending bars 101 can be connected to the tunnel section of a tunnel-type thruster (not shown in Figure 1). The first radially extending bars 101 are straight and of the same length.

[0058] The grid 100 also includes first connecting bars 102. Each of the first connecting bars 102 is connected between two adjacent first radially extending bars 101, with one end of the first connecting bar 102 connected to one of the first radially extending bars 101 and the other end of the first connecting bar 102 connected to the other first radially extending bar 101. The first connecting bars 102 are connected at the same distance from the center of the grid 100 and are curved so that they together form a circle.

[0059] Figure 2 shows a grid according to a second embodiment of the present invention. The grid in Figure 2 differs from the grid in Figure 1 in that the grid 100 further includes second connecting bars 103. Each of the second connecting bars 103 is connected between two adjacent first radially extending bars 101, with one end of the second connecting bar 103 connected to one of the first radially extending bars 101 and the other end of the second connecting bar 103 connected to the other first radially extending bar 101. The second connecting bars 103 are connected further from the center of the grid 100 than the first connecting bars 102. The second connecting bars 103 are connected at the same distance from the center of the grid 100 and are curved so that they together form a circle.

[0060] Figure 3 shows a grid according to a third embodiment of the present invention. The grid of Figure 3 differs from the grid of Figure 2 in that the grid 100 further includes second radially extending bars 104 arranged at angular intervals from each other. Each of the radially extending second bars 104 is connected to one first connecting bar 102 and one second connecting bar 103. The second radially extending bars 104 are arranged radially between the first radially extending bars 101 such that their extensions intersect at the center of the grid 100. The second radially extending bars 104 are straight and of the same length.

[0061] Figure 4 shows a grid according to a fourth embodiment of the present invention. The grid in Figure 4 differs from the grid in Figure 3 in that the grid 100 includes a central portion 105 to which the first ends of the first radially extending bars 101 are connected. In Figure 4, the central portion 105 is a disk.

[0062] Figure 5 shows a grid according to a fifth embodiment of the present invention. The grid in Figure 5 differs from the grid in Figure 4 in that the central part 105 is a ring and the first connecting bar 102 and the second connecting bar 103 are straight.

[0063] Figure 6 shows a tunnel thruster according to one embodiment of the present invention. The tunnel thruster 200 is installed on the hull 301 of a ship 300 to provide lateral thrust. The tunnel thruster 200 includes a tubular tunnel section 201 that is open at both ends. The tunnel section 201 has a round cross-section. The tunnel thruster 200 includes a propeller 202 located inside the tunnel section 201. The propeller 202 is driven by a motor (not shown in Figure 6) located outside the tunnel section 201. The motor rotates the propeller 202, generating thrust in any direction.

[0064] The tunnel thruster 200 includes a grid 100 located inside the tunnel section 201, near one end of the tunnel section 201. The ends of the first radially extending bars 101 are connected to the wall of the tunnel section 201. The number of the first radially extending bars 101 and the number of propeller blades 203 are different such that these numbers are not divisible.

[0065] Figures 7A to 7E show cross-sections of the first and second radially extending bars as examples. Figure 7A shows a cross-section of a radially extending bar having a front end 106 with one side chamfered. Figure 7B shows a cross-section of a radially extending bar having a front end 106 with one side chamfered and rear ends 107 with both sides chamfered. Figure 7C shows a cross-section of a radially extending bar with both the front end 106 and rear ends 107 rounded. Figure 7D shows a cross-section of a radially extending bar with a rounded front end 106 and rear ends 107 with both sides chamfered. Figure 7E shows a cross-section of a radially extending bar with a front end 106 that is bent laterally.

[0066] Only advantageous illustrative embodiments of the present invention are shown in the drawings. It will be apparent to those skilled in the art that the present invention is not limited to the above examples and can be modified within the scope of the claims presented below. Several possible embodiments of the present invention are described in the dependent claims and should not be considered to limit the scope of protection of the present invention.

Claims

1. A grid for a tunnel thruster, the grid being Multiple first radially extending bars arranged at predetermined angles and spaced apart from each other, A plurality of first connecting bars, each of which is connected between adjacent first radially extending bars, A plurality of second connecting bars, each of which is connected between adjacent first radially extending bars such that it is further from the center of the grid than the first connecting bar, A plurality of second radially extending bars arranged at a predetermined angle and spaced apart from each other, each of the second radially extending bars being connected between one of the first connecting bars and one of the second connecting bars, and the plurality of second radially extending bars not connected to each other at their ends, Includes, The grid is such that the first radially extending bars are flat bars, each of which has a rounded or chamfered front and rear end.

2. The grid according to claim 1, wherein the first radially extending bars are flat bars, and each of the flat bars is bent in a direction perpendicular to the longitudinal direction of the flat bar.

3. The grid according to claim 1 or 2, wherein each of the first radially extending bars is connected to an adjacent first radially extending bar by the first connecting bar.

4. The grid according to any one of claims 1 to 3, wherein the first connecting bar is connected so as to be at the same distance from the center of the grid.

5. The grid according to any one of claims 1 to 4, wherein the first ends of the first radially extending bars are connected to one another.

6. The grid according to any one of claims 1 to 4, wherein the grid includes a central portion to which the first ends of the first radially extending bars are connected.

7. The grid according to claim 1, wherein the second connecting bar is connected so as to be at the same distance from the center of the grid.

8. The grid according to claim 1, wherein the second radially extending bars are flat bars, each of which has a rounded or chamfered front and rear end.

9. The grid according to claim 1 or 8, wherein the second radially extending bars are flat bars, and each of the flat bars is bent in a direction perpendicular to the longitudinal direction of the flat bar.

10. The grid according to any one of claims 1 to 9, wherein the first and / or second radially extending bars and the first and / or second connecting bars are flat bars.

11. The grid according to any one of claims 1 to 10, wherein the number of the first radially extending bars and / or the second radially extending bars is 4 to 12.

12. It is a tunnel-type thruster, Tunnel section and A propeller positioned inside the aforementioned tunnel section, Includes, The tunnel thruster includes a grid according to any one of claims 1 to 11, which is connected to and positioned at the end of the tunnel section.

13. The tunnel thruster according to claim 12, wherein the grid is located inside the tunnel section at a distance of at least 10 mm from the end of the tunnel section.

14. The tunnel thruster according to claim 12 or 13, wherein the first radially extending bar is connected to the tunnel section.

15. The tunnel thruster according to any one of claims 12 to 14, wherein the number of the first radially extending bars is different from the number of propeller blades.

16. A ship, comprising a tunnel-type thruster according to any one of claims 12 to 15, which is installed on the hull of the ship.

Images