TWI508897B - Ship propulsion system and ship - Google Patents

Description

Ship propulsion device and ship having the same

BACKGROUND OF THE INVENTION 1. Field of the Invention This invention relates to a propulsion device for a ship using a propeller and a ship having the same. More particularly, the present invention relates to a ship that is provided with a fin on a propeller hub cap mounted on a hub of a propeller to improve the propulsion performance of the propeller. Propulsion device and ship having the same.

Most ships use propellers as their propellers, which improve the propeller efficiency and other propeller characteristics, and have a greater impact on fuel consumption. Therefore, studies on the number of wings of the propeller, the shape of the wing, the area of the spread, the pitch angle, the skew angle, and the like are related to the wing of the propeller, and various wing shapes have been developed.

For example, in order to improve the propeller characteristics, a hub cap 5 with rectifying fins, which has a rectifying fin, as shown in FIGS. 12 to 15, has been developed, as described in Japanese Patent Publication No. Hei. The hub cap 5 is attached to the vicinity of the screw hub 2 to reduce the hub vortex of the wake of the propeller hub cap 5, thereby improving the efficiency of the propeller.

In the hub cap 5 with the rectifying fins, the number of fins 6 (four in FIG. 12) and the number of each propeller blade (propeller blade) 3 attached to the hub cap 5 (in FIG. 12) For 4) equal. Further, as shown in Fig. 15, the geometrical pitch angle ε of the fin 6 with respect to the root of the propeller blade 3 has a relationship of (-20 ° ≦ α - ε ≦ + 30 °). Regarding the longitudinal direction of the fins 6, the front edge of the fins 6 is set to be the same as the trailing edge of the root portion of the propeller blade 3 in the front-rear direction of the propeller, or more rearward than the trailing edge (b≧0). Further, it is placed at a position (a>0) of the gap between the root portions of the adjacent propeller blades 3. Further, as shown in FIGS. 13 and 14, the maximum diameter (2r) from the axis of the body of the hub cap 5 of the fin 6 is larger than the diameter Dba of the hub cap mounting end portion 2a of the hub 2, and this diameter (2r) ) Set to 33% or less of the propeller diameter (2R).

The effect of the hub cap 5 with the rectifying fins can be considered as follows. The rectifying fin itself does not generate thrust, but acts as a rectifying plate that reduces the generation of the hub vortex of the wake of the hub cap. By this rectification, the hub vortex of the hub cap wake will diffuse, reducing the induced drag generated by the vortex on the propeller airfoil. As a result, the propeller characteristics (propeller efficiency) can be greatly increased without increasing the torque.

Further, as described in Japanese Patent No. 3491890, for example, a propeller having a ship vortex removing device that eliminates a vortex from a propeller hub (screw hub) such as the fin fin is proposed. The hub vortex elimination device fully and fully exerts its function to improve the overall efficiency of the propeller, and at the same time, it is also advantageous in terms of strength, so that the distance or curvature between the roots of the propeller wings is greater than the distance or curvature between the middle portions of the propeller.

On the other hand, the inventors of the present invention considered whether it is possible to further improve the efficiency of the propeller using the fin-equipped propeller hub cap, and use the fin-equipped propeller hub cap designed according to various concepts for the sink experiment. . As a result, a ship propulsion device using the following propellers, which can further improve the efficiency of the propeller, and a ship equipped with the same have been developed.

[Previous Technical Literature]

[Patent Literature]

Patent Document 1: Japanese Patent Special Publication No. 7-121716

Patent Document 2: Japanese Patent No. 3491890

It is an object of the present invention to provide a propulsion device for a ship formed by using a propeller having a finned propeller hub cap and a ship equipped therewith, and a propulsion of a ship using a finned propeller hub cap of the prior art Compared with a ship equipped with the device, the device can improve the efficiency of the propeller, and at the same time, the workability can be improved and the weight can be reduced.

The propulsion device for a ship for achieving the above object is constructed such that a fin is provided on a propeller hub cap mounted on a rear side of a propeller hub of the propeller, and the fin is disposed between the propeller blades, Forming the rear end portion of the propeller hub cap or the shape of the rear end portion of the propeller hub cap from the edge portion to converge within 20% of the entire length of the propeller hub cap, and setting the entire length of the propeller hub cap as the front end portion of the hub cap The diameter is 0.28 to 0.76 times, and the diameter of the rear end portion of the hub cap of the propeller hub cap is set to be 0.35 to 0.95 times the diameter of the front end portion of the hub cap.

Regarding the propulsion efficiency of the propeller, the total length of the propeller hub cap is preferably 0.28 to 0.76 times, preferably 0.34 to 0.68 times, preferably 0.50 times, and the diameter of the rear end of the hub cap is the hub. The diameter of the front end portion of the cap is 0.35 to 0.95 times, preferably 0.42 to 0.85 times, and most preferably 0.65 times. Therefore, the hub cap body of the propeller hub cap can be made into an optimum shape by the above configuration, and Improve propeller efficiency. At the same time, since the end portion of the propeller hub cap is formed by the end face, it is easy to work. Further, since the front end portion of the rotating body having the tapered shape is not present on the rear end side, weight reduction can be achieved accordingly.

Further, the propulsion device for a ship for achieving the above object is configured such that fins are provided on the rear side of the propeller blades of the propeller hub of the propeller, and the fins are disposed between the propeller blades, and the end faces are Forming a rear end portion of the propeller hub cap, or causing the shape of the rear end portion of the propeller hub cap to converge from the edge portion within 20% of the entire length of the propeller hub cap, and simultaneously connecting the front end of the root portion of the fin to the root end of the fin The distance is set to be 0.28 to 0.76 times the diameter of the screw hub at the rear end of the propeller blade, and the diameter of the rear end of the root of the fin is set to be 0.35 to 0.95 times the diameter of the screw hub at the rear end of the propeller blade. With this configuration, the same effects as described above can be obtained.

Further, in the propulsion device for a ship described above, the propeller hub cap is formed by a rotating body having a propeller rotating shaft as a rotating shaft, and the bus bar of the rotating body is linear, and the propeller hub cap is formed into a truncated cone shape. . With this configuration, the shape of the propeller hub cap can be changed to a simple shape, so that the workability is better and the manufacturing cost can be reduced.

Further, the ship for achieving the above object is configured to include the propulsion device of the above-described ship. In this way, we can promote the improvement of efficiency.

According to the propulsion device for a ship according to the present invention, in the propulsion device formed by using the propeller with the fin-shaped propeller hub cap, the hub cap body of the propeller hub cap is set to an optimum shape, thereby improving the propeller effectiveness. At the same time, since the end portion of the propeller hub cap is formed by the end face, it is easy to work. Further, since the front end portion of the rotating body having the tapered shape is not present on the rear end side, weight reduction can be achieved accordingly.

Further, according to the ship including the propulsion device of the ship of the present invention, since the propulsion device of the ship having a high efficiency of the propeller is used, the propulsion efficiency can be improved. Further, since the propulsion device is slightly lighter, the support structure of the propulsion shaft and the propulsion shaft can be made lighter.

Hereinafter, embodiments of a ship propulsion device and a ship including the same according to the present invention will be described with reference to the drawings. Furthermore, for ease of understanding, FIGS. 1 to 4 and FIGS. 10 to 17 are diagrams showing changes in the shape or size of a screw hub, a propeller blade, a propeller hub cap, a fin, etc., and the shape or size and actuality. different. In addition, in FIGS. 3, 4, 10, 11, and 14 to 17, in order to facilitate the observation, the propeller blades or fins which are taken for granted are omitted from the drawings or the description.

As shown in FIG. 1 and FIG. 2, the propulsion device 1A for a ship according to this embodiment is constituted by a propeller including a propeller hub (propeller hub) 2, a propeller blade 3 attached to the propeller hub 2, and a connection. A propeller hub cap (propeller hub cap) 5A at the rear end of the screw hub 2, and a fin 6 provided on the propeller hub cap 5A.

The fins 6 are provided on the propeller hub cap 5A attached to the rear side of the propeller hub 2 of the propeller 1A, and the fins 6 are disposed behind the propeller blades 3. That is, when viewed from the direction behind the propeller shaft Pc, the front end of the root portion of the fin 6 is disposed between the rear ends of the root portions of the propeller blades 3. Further, when viewed from the side, the front end of the root portion of the fin 6 is disposed further rearward than the rear end of the root portion of the propeller blade 3. The fins 6 may be formed with positive and negative curvatures, but are preferably in the form of a flat plate in terms of ease of work and reduction in production cost. Moreover, the fins 6 can also be mounted with positive and negative oblique angles. Regarding the shape or arrangement of the fins 6, well-known techniques are used.

Further, in this embodiment, the propeller hub cap 5A is formed as follows. First, the propeller hub cap 5A is formed by a rotating body that uses the propeller rotating shaft Pc as a rotating shaft. Regarding the side surface 5b of the rotating body, a bus bar of a rotating body is formed by a smooth curve or a straight line. At the same time, the rotating system is formed in a shape that is tapered toward the rear end. Further, the end portion 5a of the propeller hub cap 5A is formed by an end surface.

As shown in FIG. 3, when the bus bar of the rotating body forming the outer peripheral surface 5b of the propeller hub cap 5A is made straight, the shape of the propeller hub cap 5A becomes a truncated cone. Therefore, it is very easy to manufacture.

Further, as shown in FIG. 4, when the bus bar of the rotating body is a smooth curve, the shape is tapered from the front toward the rear, and preferably in a cross section perpendicular to the propeller rotation axis Pc. The deviation of the shape of the self-cutting cone is set to be within 0% to 20%.

That is, it is formed to be smaller than the line segment L1 of the point of 1.2 Dcf connecting the front end portion 5f and the point of 1.2 Dca of the rear end portion 5a, and is 1.0 Dcf of the connection front end portion 5f and 1.0 Dca of the rear end portion 5a. The line segment L2 at the point is larger. In other words, it is formed more inwardly from the 1.2Dcf of the front end portion 5f and the truncated cone formed by the 1.2Dca of the rear end portion 5a, which is 1.0Dcf from the front end portion 5f and 1.0Dca from the rear end portion 5a. The truncated cone formed is located further to the outside. That is, the outer shape of the propeller hub cap 5A is formed in the manner of being in the oblique line portion of FIG. Further, the end portion 5a of the propeller hub cap 5A is formed by the end surface.

Further, the total length Lc of the propeller hub cap 5A is set to be 0.28 to 0.76 times, preferably 0.34 to 0.68 times, and most preferably 0.50 times the diameter Dcf of the distal end portion of the hub cap. Further, the diameter Dca of the end portion 5a of the propeller hub cap 5A is set to 0.35 to 0.95 times, preferably 0.42 to 0.85 times, and most preferably 0.65 times the diameter Dcf of the front end portion 5f of the propeller hub cap 5A. . Further, the diameter Dcf of the front end portion 5f corresponds to the flange diameter of the hub cap.

Further, as shown in FIGS. 3 and 4, the end surface of the front end portion 5f of the propeller hub cap 5A is formed into a planar shape by being joined to the end face 2a of the screw hub 2. On the other hand, the end face of the end portion 5a of the propeller hub cap 5A is as shown in Fig. 3, and is preferably formed in a plane from the viewpoint of operation, but as shown in Fig. 4, it is also close to a plane cone or rotation. Body formation. In this case, the distance Lca between the edge portion 5ao of the rear end portion 5a and the front-rear direction of the center portion 5ac is also set to be within 20% of the total length Lc of the propeller hub cap 5A.

Next, in the present invention, the total length Lc of the propeller hub cap 5A is set to be 0.28 to 0.76 times, preferably 0.34 to 0.68 times, and most preferably 0.50 times the diameter Dcf of the distal end portion of the hub cap. This will be described below.

Fig. 5 shows the results of a sink test of the propeller by changing the length of the hub cap (the total length of the propeller hub cap) Lc. The horizontal axis represents the "hub cap length / the diameter of the hub end portion (Lc / Dcf)", and the vertical axis indicates the rate of increase of the thruster efficiency.

The original propeller hub cap 5A having a rising rate of zero is formed by a normal rotating body whose front end side is tapered and whose diameter is gradually reduced and becomes zero at the last end, and Lc/Dcf is set to 0.80. This is taken as the basis of the rate of increase (the rate of increase is zero), and the thruster efficiency when the screw boss cap 5A of the conical shape of Fig. 3 is formed to planarly form the end face of the rear end portion is indicated by the rate of increase. Further, the fins 6 attached to the propeller hub cap 5A are formed in a flat plate shape, and when the "hub cap length/the diameter of the hub cap front end portion (Lc/Dcf)" is changed, the fins 6 are The length is set to a length proportional to the length of the hub cap.

As can be seen from Fig. 5, based on the experimental results of the propeller forward rate J (= V / nDp, V is the forward speed, n is the propeller speed, and Dp is the propeller diameter) as the propeller forward rate of the propeller design point, it is known that Lc/Dcf When the ratio is 0.28 times to 0.76 times, the rate of increase is 1.4%, and when Lc/Dcf is 0.34 times to 0.68 times, the rate of increase is 1.8%, and when Lc/Dcf is 0.50 times, the rate of increase is the largest. . In the present invention, Lc/Dcf is in the range of 0.28 to 0.76 times Z1 based on the results of the experiments.

Next, the diameter Dca of the end portion 5a of the propeller hub cap 5A is set to 0.35 to 0.95 times, preferably 0.42 to 0.85 times, and most preferably 0.65 times the diameter Dcf of the tip end portion 5f. This will be described below.

Fig. 6 shows an experimental result obtained by changing the diameter Dca of the end portion 5a after the propeller hub cap 5A and changing the shape of the propeller hub cap 5A in a state where the hub cap length Lc is fixed to Lc/Dcf = 0.71. The horizontal axis represents the diameter of the rear end of the hub cap/the diameter of the front end of the hub cap (Dca/Dcf), and the vertical axis indicates the rate of increase of the thruster efficiency.

As can be seen from Fig. 6, the shape of the propeller hub cap 5A is preferably such that the diameter Dca of the rear end portion 5a is smaller than the diameter Dcf of the front end portion, and it is also known that the ratio Dca/Dcf has an optimum range. That is, according to the experimental result of the propeller advancing rate J as the propeller advancing rate of the propeller design point, it can be seen that when the Dca/Dcf is 0.35 to 0.95 times, the rate of increase is 1.0%, and the Dca/Dcf is 0.42 times. In the case of -0.85 times, the rate of increase is 1.2%, and when Dca/Dcf is 0.65 times, the rate of increase is at most 1.5%. In the present invention, Dca/Dcf is set in the range Z2 of 0.35 to 0.95 times based on the results of the experiments.

Further, in order to investigate the influence of the fins 6 on the propeller characteristics, the force acting on the fins 6 was experimentally determined, and as a result, it was found that the thrust Tf acts on the fins 6 with respect to the thrust Tp acting on the propeller blades 3 and the torque Qp. The propeller hub cap 5A, although the torque Qf is small but also acts on the fin 6, the overall thrust Tt and torque Qt will be improved.

Further, it is understood by numerical fluid dynamics calculation (CFD (Computational Fluid Dynamics) calculation) that the hub vortex diffuses and the static pressure rises after the propeller hub cap 5A, and as a result, the static pressure becomes the end portion after pressing the propeller hub cap 5A. The force on the end face of 5a will contribute to the improvement of the overall thrust Tt. From this, it is understood that even if the end surface of the end portion 5a of the propeller hub cap 5A is a flat or nearly planar shape, it will contribute to the improvement of the overall thrust Tt.

Considering the relationship between the shape of the propeller hub cap 5A and the propeller efficiency, the water flow through the propeller blades 3 will be shrunk and flow backward. This is shown in a certain portion of the propeller hub cap 5A, and the direction of the water flow is not toward the same cylindrical surface parallel to the propeller shaft Pc, but is a direction gradually decreasing from the hub cap flange 2a toward the propeller rotation axis Pc. Therefore, the flow of water flowing on the surface of the side surface 5b of the propeller hub cap 5A is affected by the flow of the water. Therefore, it is more preferable to shape the side surface 5b of the propeller hub cap 5A to a shape in which the diameter of the rear end side is reduced along the contraction flow.

Also, consider the mounting angle of the fins 6 (α of Fig. 15) or curvature. Figure 7 shows the shape and curvature of the wings of the root of the propeller blade 3. For comparison therewith, Fig. 8 shows the expanded shape of the trapezoidal hub cap and the root shape of the fins 6 on the surface of the propeller hub cap 5A. A (circular mark) indicates a case where the flat fin 6 is attached to the propeller hub cap 5A having a trapezoidal side cross section as shown in FIG. Further, B (diamond) indicates a case where the propeller hub cap 5A of the prior art shown in Fig. 14 is attached.

If the shape of the root of the fin 6 is observed on the developed view of the surface of the propeller hub cap 5A, the curvature of the wing of the root of the propeller blade 3 shown in FIG. 7 is compared with that of the blade (Camber). On the expanded view, both A and B have the curvature in the opposite direction. Furthermore, the ε line of Fig. 7 indicates the line of the angle between the roots of the propellers 3 (ε of Fig. 15).

The α line of Fig. 8 indicates the line of the mounting angle of the fin 6 (α of Fig. 15). In Fig. 8, most of the shape of the root of the fin 6 is located on the alpha line, and in the wake of the propeller, the flow of water on the surface of the fin flows along the line. The water flow along the fin 6 flows as shown in Fig. 8 along the curvature from the alpha line in the opposite direction to the propeller blade 3. In this case, the torque Qf generated by the fin 6 is compared with that of the propeller blade 3. The generated torque Qp is the torque in the opposite direction, and the torque Qf is generated in the direction in which the torque Qp is eliminated.

On the other hand, the propulsive force generated by the fins 6 is generated in the opposite direction to the thrust Tp generated by the propeller blades 3, but the fins 6 vortex the hub and increase the static pressure behind the hub cap, thereby becoming The force of pressing the end face of the end portion 5a of the hub cap. As a result, the thrust Tf generated by the hub cap 5A and the fins 6 acts in the direction of the thrust Tp generated by the propeller blades 3, thereby improving the efficiency of the propeller.

In the developed view shown in Fig. 9, C (circular mark) indicates the case of the cylindrical propeller hub cap 5C as shown in Fig. 10, and D (diamond) indicates the rear end side as shown in Fig. 11. Expand the case of the diffused propeller hub cap 5D. As shown in FIG. 9, in these cases C and D, the pitch angle becomes larger than the line of α, and has a curvature in the same direction as the propeller blade 3. In this case, the torque Qf generated by the fins 6 is generated in the same direction as the torque Qp generated by the propeller blades 3, that is, in the direction of increasing the overall torque Qt, contributing less to the improvement of the thruster efficiency.

Thus, it can be seen that even if the mounting angle of the fins 6 is the same, the shape of the propeller hub cap 5A affects the flow of water with respect to the roots of the fins 6 on the surface of the propeller hub cap 5A.

As the mounting angle of the fins 6, the oblique angle γ as shown in Figs. 16 and 17 can be added in the same manner as the finned hub cap 5 of the prior art. Fig. 17 shows a case where the inclination angle γ of the fin 6 is mounted at 0 degrees and the case where it is mounted at a positive angle (+γ) or a negative angle (-γ).

The ship including the propulsion device for a ship of the present invention includes the propulsion device 1A of the above-described ship. According to the ship, since the propulsion device 1A of the above-described ship is used, it is possible to improve the propulsion efficiency. Further, since the propulsion device 1A can be slightly lightened, the support structure of the propulsion shaft and the propulsion shaft can be made lighter.

(industrial availability)

The propulsion device of the ship of the present invention is a propulsion device formed by using a propeller with a fin-shaped propeller hub cap, which can improve the efficiency of the propeller while making work easier and lightweight, and thus can be used as The propulsion device of the ship.

Further, the ship including the propulsion device of the ship of the present invention can improve the propulsion efficiency, and the weight of the propulsion device can reduce the support structure of the propeller shaft and the propeller shaft, and thus can be used for most ships.

1, 1A. . . Ship propulsion device

2. . . Screw hub

2a. . . End face of the screw hub

2r. . . The maximum diameter

2R. . . Propeller diameter

3. . . Propeller wing

4. . . Propeller rotation axis

5, 5A, 5C, 5D. . . Propeller hub cap

5a. . . Propeller hub cap rear end

5ao. . . Edge of the rear end

5ac. . . Central part of the rear end

5b. . . The outer circumference of the propeller hub cap

5f. . . Front end

6. . . Fin

C. . . Round mark

D‧‧‧Rhombus

Dba‧‧‧ diameter of the mounting end of the hub cap

Dca‧‧‧Diameter of the rear end of the propeller hub cap

Dcf‧‧‧ diameter of the front end of the propeller hub cap

Dp‧‧‧propeller diameter

L1, L2‧‧‧ segments

Lc‧‧‧full length of propeller hub cap (hub cap length)

Lca‧‧‧The distance between the edge of the rear end and the front and rear of the center

Pc‧‧·propeller shaft

Torque produced by Qf‧‧‧ fins

Qp‧‧‧Torque generated by the propeller wing

Torque generated by the Qt‧‧‧ propulsion device

Tf‧‧‧Thrusts generated by fins and hubcaps

Tp‧‧‧ thrust generated by the propeller wing

Thrust generated by the Tt‧‧‧ propulsion device

Mounting angle of α‧‧‧ fins

Installation angle of γ‧‧‧ fins

ε‧‧‧The angle between the roots of the propeller blades

Fig. 1 is a view showing the configuration of a ship propulsion device according to an embodiment of the present invention as seen from the rear of the ship.

Figure 2 is a side elevational view of the propulsion unit of the vessel of Figure 1.

Figure 3 is a schematic side elevational view of the side section of the propeller hub cap showing a trapezoidal shape.

Figure 4 is a schematic side elevational view of a side section of the propeller hub cap showing a smooth curve shape.

Fig. 5 is a view showing the relationship between "hub cap length/hub cap tip diameter" and "propeller efficiency increase rate" in the propulsion device of the ship.

Fig. 6 is a view showing the relationship between the "hub cap rear end diameter/hub cap front end diameter" and the "propeller efficiency increase rate" in the propulsion device of the ship.

Fig. 7 is a view showing the arrangement of the roots of the propeller blades on the surface of the screw hub.

Figure 8 is a diagram showing the arrangement of the fin roots on the surface of the helical propeller hub cap and the prior art propeller hub cap.

Fig. 9 is a view showing the arrangement of the fin roots on the surface of the cylindrical propeller hub cap and the diffusion type propeller hub cap.

Fig. 10 is a schematic side view showing a cylindrical propeller hub cap.

Figure 11 is a schematic side view showing a propeller hub of a diffusion type.

Fig. 12 is a view showing the construction of the propulsion device of the prior art from the rear of the ship.

Figure 13 is a side elevational view of the propulsion unit of the vessel of Figure 12.

Figure 14 is a side elevational view showing the shape of a prior art propeller hub cap.

Figure 15 is a side elevational view showing the positional relationship of the prior art propeller blades and fins.

Figure 16 is a side view showing the mounting angle of the fins.

Fig. 17 is a cross-sectional view taken along line A-A of Fig. 16 showing the oblique angle of the fin viewed from the rear.

2. . . Screw hub

2a. . . End face of the screw hub

5A. . . Propeller hub cap

5a. . . Propeller hub cap rear end

5ao. . . Edge of the rear end

5ac. . . Central part of the rear end

5b. . . The outer circumference of the propeller hub cap

5f. . . Front end

6. . . Fin

Pc. . . Propeller shaft

Dca. . . Diameter of the rear end of the propeller hub cap

Dcf. . . The diameter of the front end of the propeller hub cap

L1, L2. . . Line segment

Lc. . . The total length of the propeller hub cap (hub cap length)

Lca. . . The distance between the edge of the rear end and the front and rear of the center

Claims (4)

A propulsion device for a ship is provided with a fin disposed on a propeller hub cap mounted on a rear side of a propeller hub of the propeller, and the fin is disposed between the propeller blades; wherein the propeller hub cap is disposed behind The shape of the end portion is formed by a plane, or the shape of the rear end portion of the propeller hub cap is formed as a cone close to a plane, and the cone has a distance between the edge portion of the rear end portion and the center portion in the front-rear direction. In the range of 20% of the total length of the propeller hub cap, or the shape of the rear end portion of the propeller hub cap is formed as a planar rotating body, the rotating system has the edge portion of the rear end portion and the center portion in the front-rear direction The distance is set to be within 20% of the total length of the propeller hub cap, and the total length of the propeller hub cap is set to be 0.28 to 0.76 times the diameter of the front end portion of the hub cap, and the diameter of the rear end portion of the hub cap of the propeller hub cap is It is set to 0.35 times to 0.95 times the diameter of the front end portion of the hub cap. A propulsion device for a ship, which is provided with a fin on a rear side of a propeller blade of a propeller hub of a propeller, and a fin is disposed between the propeller blades; and the rear end portion of the propeller hub cap is made The shape is formed by a plane, or the shape of the rear end portion of the propeller hub cap is formed as a plane-cone, and the cone is formed by setting the distance between the edge portion of the rear end portion and the center portion in the front-rear direction as the propeller. Within 20% of the total length of the hub cap, Alternatively, the shape of the rear end portion of the propeller hub cap is formed as a planar rotating body, and the rotation system sets the distance between the edge portion of the rear end portion and the center portion in the front-rear direction as 20% of the total length of the propeller hub cap. In the range, the distance between the front end of the root of the fin and the rear end of the fin is set to be 0.28 to 0.76 times the diameter of the screw hub at the rear end of the propeller wing, and the root end of the fin is The diameter is set to be 0.35 to 0.95 times the diameter of the screw hub of the rear end of the propeller blade. The propulsion device for a ship according to the first aspect of the invention, wherein the propeller hub cap is formed by a rotating body that uses the propeller rotating shaft as a rotating shaft, and the bus bar of the rotating body is a straight line, so that the propeller hub The cap is formed in a truncated cone shape. A ship characterized by comprising a propulsion device for a ship according to any one of claims 1 to 3.