Steering gear

Abstract

To provide a steering gear capable of efficiently navigating a vessel by suppressing resistance of a left rudder plate and a right rudder plate.SOLUTION: A port side rudder plate is formed of a left front rudder plate 10 fixed to a bottom of a vessel and a left rear rudder plate 11 provided on rear side of the left front rudder plate, the left rear rudder plate 11 is formed of a first left rear rudder plate 31 in a front unit and a second left rear rudder plate 32 provided on a rear side of the first left rear rudder plate rear unit, a front unit of the first left rear rudder plate is fixed to be freely rotatable to a left rudder shaft 15 extending in a vertical direction on left side of a propeller, a front unit of the second left rear rudder plate is fixed to be freely rotatable to a left flap shaft 34 extending in the vertical direction on a rear unit of the first left rear rudder plate, a left support shaft 35 extending in the vertical direction is provided between the left rudder shaft and a left flap shaft in a side view, a top unit of the left support shaft is fixed to the bottom of the vessel, a left engaging member 36 having a through hole is provided in a top unit of the second left rear rudder plate, the left support shaft and the left engaging member are coupled by a left coupling member 38, and a starboard side rudder plate is in a same composition.SELECTED DRAWING: Figure 10

Description

[Technical field]

[0001] The present invention relates to a steering device for a ship. [Background technology]

[0002] A technique is known in which a left rudder and a right rudder are provided on either side of a propeller to improve the propulsive performance of a ship. It is also known that after a ship is completed, the turning performance, which allows the ship to quickly change course, and the course-keeping performance, which allows the ship to run straight, are measured. (Patent Document 1) [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2014-73815 A Summary of the Invention [Problem to be solved by the invention]

[0004] However, while the means of Patent Document 1 can improve the propulsion performance of the ship, there is a risk that it will not be possible to sufficiently improve the turning performance. Also, if the left rudder plate of the port side rudder and the right rudder plate of the starboard side rudder become large, there is a risk that the left rudder plate and the right rudder plate will create resistance and the ship will not be able to travel efficiently, and there is a risk that the shaft diameter of the left rudder stock that suspends the left rudder plate and the right rudder stock that suspends the right rudder plate will become excessively thick.

[0005] Therefore, the main objective of the present invention is to provide a steering device that can improve the propulsion performance of a ship and the turning performance, which has a large effect on the maneuverability. The second objective is to provide a steering device that can reduce the resistance of the left and right rudder plates and enable the ship to travel efficiently. [Means for solving the problem]

[0006] The present invention, which has solved the above problems, is as follows. The invention according to claim 1 relates to a steering device in which a port side rudder board is arranged on the left side of a ship's propeller and a starboard side rudder board is arranged on the right side of the propeller, The port side rudder board is formed by a left front rudder board fixed to the bottom of the ship and a left rear rudder board provided on the rear side of the left front rudder board, the left rear rudder board is formed by a first left rear rudder board at the front and a second left rear rudder board provided on the rear side of the rear part of the first left rear rudder board, the starboard side rudder board is formed by a right front rudder board fixed to the bottom of the ship and a right rear rudder board provided on the rear side of the right front rudder board, and the right rear rudder board is formed by a first right rear rudder board at the front and a second left rear rudder board provided on the rear side of the first left rear rudder board. rightThe first left rudder plate is formed by a second right rear rudder plate provided on the rear side of the rear part of the rear rudder plate, the front part of the first left rudder plate is rotatably fixed to a left rudder shaft extending vertically to the left of the propeller, the front part of the second left rudder plate is rotatably fixed to a left flap shaft extending vertically to the rear part of the first left rudder plate, and a left support shaft extending vertically is provided between the left rudder shaft and the left flap shaft in a side view, the upper part of the left support shaft is fixed to the bottom of the ship, and a through hole is provided in the upper part of the second left rudder plate. a left engaging member having a right rudder shaft, the left support shaft and the left engaging member are connected by a left connecting member, the front part of the first right rear rudder plate is rotatably fixed to a right rudder shaft extending vertically to the right of the propeller, the front part of the second right rear rudder plate is rotatably fixed to a right flap shaft extending vertically to the rear part of the first right rear rudder plate, a right support shaft extending vertically is provided between the right rudder shaft and the right flap shaft in a side view, and an upper part of the right support shaft is fixed to the bottom of the ship, and the second right rear rudder plate is A right engaging member having a through hole is provided at the top of the right support shaft, and the right engaging member is connected with a right connecting member. The left rear rudder plate is formed of a left vertical portion provided on the rear side of the left front rudder plate and a left inclined portion extending downward to the right from the lower part of the left vertical portion. The right rear rudder plate is formed of a right vertical portion provided on the rear side of the right front rudder plate and a right inclined portion extending downward to the left from the lower part of the right vertical portion. In a side view, the left inclined portion extends from the front of the left front rudder plate to the rear of the left vertical portion. The right inclined portion extends from the front of the right front rudder plate to the rear of the right vertical portion, and when viewed from behind, the lower ends of the left and right inclined portions are positioned at the lower end of the propeller's turning outer periphery, the right side of the left front rudder plate is connected to the lower part of the stern by a left connecting member, and the left side of the right front rudder plate is connected to the lower part of the stern by a right connecting member, and when viewed from behind, the left connecting member is arranged parallel to the right inclined portion, and the right connecting member is arranged parallel to the left inclined portion.

[0007] The invention of claim 2 is a steering device as described in claim 1, wherein, when viewed along the axis of the left rudder stock, the first left rear rudder plate rotates 45 degrees clockwise and counterclockwise, when viewed along the axis of the left flap shaft, the second left rear rudder plate rotates 45 degrees clockwise and counterclockwise, when viewed along the axis of the right rudder stock, the first right rear rudder plate rotates 45 degrees clockwise and counterclockwise, and when viewed along the axis of the right flap shaft, the second right rear rudder plate rotates 45 degrees clockwise and counterclockwise.

[0008] The invention of claim 3 is a steering device as described in claim 1 or 2, in which the front portion of the left front rudder plate is positioned forward and to the left of the rear portion, and the front portion of the right front rudder plate is positioned forward and to the right of the rear portion.

[0009] The invention of claim 4 is a steering device described in any one of claims 1 to 3, wherein, when viewed from the left side, the fore-and-aft length of the second left rear rudder plate is approximately half the fore-and-aft length of the first left rear rudder plate, and the fore-and-aft length of the second right rear rudder plate is approximately half the fore-and-aft length of the first right rear rudder plate.

[0010] The invention of claim 5 is a steering device described in any one of claims 1 to 4, in which the left rear rudder plate is rotatably supported by the rear part of the left front rudder plate and a left rudder shaft extending in the vertical direction fixed to the left rear rudder plate, and the right rear rudder plate is rotatably supported by the rear part of the right front rudder plate and a right rudder shaft extending in the vertical direction fixed to the right rear rudder plate, and the lower end parts of the port side rudder plate and starboard side rudder plate are positioned at the lower end parts of the propeller's turning outer periphery when viewed from behind.

[0011]

[0012]

[0013] The invention according to claim 6 is the steering device according to any one of claims 1 to 5, wherein, in a plan view, the left rudder stock and the right rudder stock are provided adjacent to the rear side of the center line of the propeller in the fore-and-aft direction. Effect of the Invention

[0014] According to the invention described in claim 1, the port side rudder board is formed by a left front rudder board fixed to the bottom of the ship and a left rear rudder board provided on the rear side of the left front rudder board, the left rear rudder board is formed by a first left rear rudder board at the front and a second left rear rudder board provided on the rear side of the rear part of the first left rear rudder board, the starboard side rudder board is formed by a right front rudder board fixed to the bottom of the ship and a right rear rudder board provided on the rear side of the right front rudder board, and the right rear rudder board is formed by a first right rear rudder board at the front and a first left rear rudder board. right The first left rudder plate is formed by a second right rear rudder plate provided on the rear side of the rear part of the rear rudder plate, the front part of the first left rudder plate is rotatably fixed to a left rudder shaft extending vertically to the left of the propeller, the front part of the second left rudder plate is rotatably fixed to a left flap shaft extending vertically to the rear part of the first left rudder plate, in a side view, a left support shaft extending vertically is provided between the left rudder shaft and the left flap shaft, the upper part of the left support shaft is fixed to the bottom of the ship, and a left engagement member having a through hole is provided at the upper part of the second left rudder plate, The left support shaft and the left engagement member are connected by a left connecting member, the front part of the first right rear rudder plate is rotatably fixed to the right rudder shaft extending in the vertical direction to the right of the propeller, the front part of the second right rear rudder plate is rotatably fixed to the right flap shaft extending in the vertical direction to the rear of the first right rear rudder plate, a right support shaft extending in the vertical direction is provided between the right rudder shaft and the right flap shaft in a side view, the upper part of the right support shaft is fixed to the bottom of the ship, a right engagement member having a through hole is provided at the upper part of the second right rear rudder plate, and the right support shaft and the right The engaging members are connected by a right connecting member, the left rear rudder plate is formed by a left vertical portion provided on the rear side of the left front rudder plate and a left inclined portion extending downward to the right from the lower part of the left vertical portion, the right rear rudder plate is formed by a right vertical portion provided on the rear side of the right front rudder plate and a right inclined portion extending downward to the left from the lower part of the right vertical portion, in a side view, the left inclined portion extends from the front of the left front rudder plate to the rear of the left vertical portion, and the right inclined portion extends from the front of the right front rudder plate to the rear of the right vertical portion, in a rear view, the left inclined portion extends from the front of the right front rudder plate to the rear of the right vertical portion, The lower ends of the inclined portion and the right inclined portion are positioned at the lower end of the propeller's turning circumference, the right side of the left front rudder board is connected to the lower part of the stern by a left connecting member, and the left side of the right front rudder board is connected to the lower part of the stern by a right connecting member, and when viewed from behind, the left connecting member is arranged parallel to the right inclined portion, and the right connecting member is arranged parallel to the left inclined portion, so that a large camber curve is formed in the port side rudder board and the starboard side rudder board, which can generate large lift and also reduce the ship's turning radius. In addition, the efficiency of the propeller can be improved by increasing the flow rate of the water flowing into the propeller from in front of the propeller, and the energy loss of the high-speed rotating flow exiting the propeller can be suppressed by efficiently recovering the energy of the rotating flow. Furthermore, the flow rate of the water flowing into the propeller from in front of the propeller can be increased, thereby further improving the efficiency of the propeller.

[0015] According to the invention described in claim 2, in addition to the effects described in claim 1, when viewed from the axis of the left rudder stock, the first left rear rudder plate rotates 45 degrees clockwise and counterclockwise, when viewed from the axis of the left flap shaft, the second left rear rudder plate rotates 45 degrees clockwise and counterclockwise, when viewed from the axis of the right rudder stock, the first right rear rudder plate rotates 45 degrees clockwise and counterclockwise, and when viewed from the axis of the right flap shaft, the second right rear rudder plate rotates 45 degrees clockwise and counterclockwise, so that a larger camber curve is formed by the port side rudder plate and the starboard side rudder plate, which can generate a larger lift and also make the turning radius of the ship smaller.

[0016] According to the invention described in claim 3, in addition to the effects of the invention described in claim 1 or 2, the front part of the left front rudder plate is positioned further forward and to the left than the rear part, and the front part of the right front rudder plate is positioned further forward and to the right than the rear part, so that when the ship is moving straight ahead, lift is generated on the left and right front rudder plates, thereby improving the propulsion efficiency of moving the ship straight ahead.

[0017] According to the invention described in claim 4, in addition to the effects of the invention described in any one of claims 1 to 3, when viewed from the left side, the fore-and-aft length of the second left rear rudder plate is formed to be approximately half the fore-and-aft length of the first left rear rudder plate, and the fore-and-aft length of the second right rear rudder plate is formed to be approximately half the fore-and-aft length of the first right rear rudder plate, so that the second left rear rudder plate and the second right rear rudder plate can be easily rotated without requiring excessive force.

[0018] According to the invention described in claim 5, in addition to the effects of the invention described in any one of claims 1 to 4, the left rear rudder is rotatably supported by the rear part of the left front rudder and the left rudder shaft fixed to the left rear rudder, and the right rear rudder is rotatably supported by the rear part of the right front rudder and the right rudder shaft fixed to the right rear rudder, and the lower ends of the port side rudder and starboard side rudder are located at the lower end of the propeller's turning periphery in rear view, so that the resistance of the port side rudder and starboard side rudder when the ship is sailing can be suppressed and the ship can sail efficiently. Also, the turning performance of the ship can be improved, and the ship's vertical distance and turning circle can be shortened.

[0019]

[0020]

[0021] According to the invention described in claim 6, in addition to the effects of the invention described in any one of claims 1 to 5, in plan view, the left and right rudder stocks are provided close to the rear of the center line of the propeller in the longitudinal direction, so that the left and right rear rudder boards rotated via the left and right rudder stocks can be prevented from interfering with the propeller. Also, the high-speed water flow into the propeller and the high-speed rotating flow out of the propeller can be made to flow along the port and starboard rudder boards, so that lift can be generated on the port and starboard rudder boards. [Brief description of the drawings]

[0022] [Figure 1] FIG. 2 is a perspective view of the first steering device as viewed from the rear right side. [Diagram 2] FIG. [Diagram 3] FIG. 2 is a longitudinal cross-sectional view of the steering device in the front-rear direction. [Figure 4] 4 is a cross-sectional view taken along line AA in FIG. [Diagram 5] FIG. 2 is a plan view of the steering device when traveling straight. [Figure 6] FIG. 2 is a plan view of the steering device when turning left. [Figure 7] FIG. 11 is a perspective view of the second steering device as seen from the rear right side [Figure 8]FIG. [Figure 9] FIG. 2 is a longitudinal cross-sectional view of the steering device in the front-rear direction. [Figure 10] FIG. 13 is a rear perspective view of the third steering device. [Figure 11] FIG. 4A is a right side view of the steering device, and FIG. [Figure 12] (a) is a rear view of the steering device, and (b) is a bottom view. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0023] <First steering device> As shown in FIGS. 1 to 3, the first steering device includes a port side rudder blade 2 arranged on the left side of the propeller 1 and a starboard side rudder blade 3 arranged on the right side of the propeller 1 .

[0024] The port side rudder blade 2 is formed of a left front rudder blade 10 located at the front and a left rear rudder blade 11 provided on the rear side of the left front rudder blade 10. The starboard side rudder blade 3 is formed of a right front rudder blade 20 located at the front and a right rear rudder blade 21 provided on the rear side of the right front rudder blade 20.

[0025] The left front rudder plate 10 is formed to extend in the vertical direction, and its upper part is fixed to the lower part of the stern. In addition, a rectangular left convex part 10A is formed on the rear lower part of the left front rudder plate 10, which protrudes toward the left rear rudder plate 11 more than the rear upper part, and a left support shaft 12 extending in the vertical direction is provided on the lower part of the left convex part 10A.

[0026] The left rear rudder blade 11 is formed of a left vertical portion 13 extending in the up-down direction and a left inclined portion 14 formed with a rightward downward inclination from the lower end of the left vertical portion 13 in rear view. In addition, in side view, the front part of the left inclined portion 14 formed in a substantially rectangular shape is located in front of the left front rudder blade 10, and the rear part is located behind the left vertical portion 13.

[0027] A left rudder stock 15 extending in the up-down direction is provided at the upper part of the left vertical part 13, and a rectangular left recess 13A is formed at the front lower part of the left vertical part 13 into which the left protrusion 10A is inserted.

[0028] The upper part of the left rudder stock 15 extends into the steering room, and a steering (not shown) for rotating the left rudder stock 15 is connected to the upper part of the left rudder stock 15. The lower part of the left rudder stock 15 is rotatably fixed to the upper part of the left convex part 10A. As the steering, either a rotary vane steering or a Rapson slide steering can be used.

[0029] The left vertical part 13 is rotatably supported on the left convex part 10A via the left support shaft 12 and the left rudder stock 15, and the axes of the left support shaft 12 and the left rudder stock 15 are aligned when viewed from the axis of the left rudder stock 15. This allows the load of the left rear rudder board 11 to be distributed and supported by the left front rudder board 10 and the left rudder stock 15, preventing the shaft diameter of the left rudder stock 15 from becoming excessively thick.

[0030] The right front rudder plate 20 is formed to extend in the vertical direction, and its upper part is fixed to the lower part of the stern. In addition, a rectangular right convex part 20A is formed on the rear lower part of the right front rudder plate 20, which protrudes toward the right rear rudder plate 21 more than the rear upper part, and a right support shaft 22 extending in the vertical direction is provided on the lower part of the right convex part 20A.

[0031] The right rear rudder blade 21 is formed of a right vertical portion 23 extending in the up-down direction and a right inclined portion 24 formed in a left downward inclination from the lower end of the right vertical portion 23 in rear view. In addition, in side view, the front part of the right inclined portion 24 formed in a substantially rectangular shape is located in front of the right front rudder blade 20, and the rear part is located behind the right vertical portion 23.

[0032] A right rudder stock 25 extending in the up-down direction is provided at the upper part of the right vertical part 23, and a rectangular right recess 23A is formed at the front lower part of the right vertical part 23 into which the right protrusion 20A is inserted.

[0033] The upper part of the right rudder stock 25 extends into the steering room, and a steering (not shown) for rotating the right rudder stock 25 is connected to the upper part of the right rudder stock 25. The lower part of the right rudder stock 25 is rotatably fixed to the upper part of the right convex part 20A. Note that either a rotary vane steering or a Rapson slide steering can be used as the steering.

[0034] The right vertical part 23 is rotatably supported on the right convex part 20A via the right support shaft 22 and the right rudder stock 25, and the axes of the right support shaft 22 and the right rudder stock 25 are aligned when viewed from the axis of the right rudder stock 25. This allows the load of the right rear rudder board 21 to be distributed and supported by the right front rudder board 20 and the right rudder stock 25, preventing the shaft diameter of the right rudder stock 25 from becoming excessively thick.

[0035] In rear view, the left vertical portion 13 of the left front rudder plate 10 and the left rear rudder plate 11 is provided at a predetermined distance to the left of the left end of the circumferential periphery of the propeller 1, and the right vertical portion 23 of the right front rudder plate 20 and the right rear rudder plate 21 is provided at a predetermined distance to the right of the right end of the circumferential periphery of the propeller 1. This makes it possible to suppress corrosion due to cavitation on the right side of the left vertical portion 13 of the left front rudder plate 10 and the left rear rudder plate 11 and the left side of the right vertical portion 23 of the right front rudder plate 20 and the right rear rudder plate 21.

[0036] When viewed from the rear, it is preferable to position the lower end of the left vertical portion 13 of the left rear rudder blade 11 and the lower end of the right vertical portion 23 of the right rear rudder blade 21 at approximately the center in the vertical direction between the center of the propeller 1 and the lower end of the propeller 1's turning periphery, and to position the lower end of the left inclined portion 14 of the left rear rudder blade 11 and the lower end of the right inclined portion 24 of the right rear rudder blade 21 at the lower end of the propeller 1's turning periphery.

[0037] In the case of a coastal ship, as shown in Fig. 2, it is preferable to position the lower end of the left inclined portion 14 of the left rear rudder board 11 and the lower end of the right inclined portion 24 of the right rear rudder board 21 below the lower end of the turning periphery of the propeller 1. This improves the turning performance of the ship and shortens the ship's vertical distance and turning circle. On the other hand, in the case of an ocean-going ship, it is preferable to position the lower end of the left inclined portion 14 of the left rear rudder board 11 and the lower end of the right inclined portion 24 of the right rear rudder board 21 above the lower end of the turning periphery of the propeller 1. This reduces the resistance of the left rear rudder board 11 and the right rear rudder board 21, allowing the ship to sail efficiently.

[0038] In the rear view, it is preferable to provide the left connecting member 16 on the left front rudder plate 10, which connects the upper part of the left front rudder plate 10 to the lower part of the stern, and the right front rudder plate 20, which connects the upper part of the right front rudder plate 20 to the lower part of the stern. The left connecting member 16 is formed parallel to the right inclined part 24 and is provided at a position symmetrical to the right inclined part 24 with the propeller 1 as the center, and the right connecting member 26 is formed parallel to the left inclined part 14 and is provided at a position symmetrical to the left inclined part 14 with the propeller 1 as the center. This makes it possible to increase the flow speed of the water flowing into the propeller 1 from the front of the propeller 1, thereby improving the efficiency of the propeller 1. In addition, in the side view, the length in the front-rear direction of the left connecting member 16 is formed to be approximately the same as the length in the front-rear direction of the left front rudder plate 10, and the length in the front-rear direction of the right connecting member 26 is formed to be approximately the same as the length in the front-rear direction of the right front rudder plate 20.

[0039] As shown in Figure 4, when the ship is sailing straight, the left and right sides of the port side rudder board 2, i.e., the left and right sides formed by the left front rudder board 10 and the left vertical part 13 of the left rear rudder board 11 that is substantially continuous with the left front rudder board 10, are preferably formed in a streamlined shape, and the left and right sides of the starboard side rudder board 3, i.e., the right front rudder board 20 and the right vertical part 23 of the right rear rudder board 21 that is substantially continuous with the right front rudder board 20, are preferably formed in a streamlined shape. This makes it possible to more effectively sail the ship by suppressing the resistance of the port side rudder board 2 and the starboard side rudder board 3 when the ship is sailing straight.

[0040] 5, the left side of the port side rudder blade 2 can be formed approximately straight and the right side can be formed bulging toward the propeller 1, and the right side of the starboard side rudder blade 3 can be formed approximately straight and the left side can be formed bulging toward the propeller 1. This can prevent the separation of the water flow occurring at the rear of the port side rudder blade 2 and the starboard side rudder blade 3, and generate lift on the port side rudder blade 2 and the starboard side rudder blade 3.

[0041] As shown in Figure 4, the port side rudder board 2 is positioned with its front part to the left of its rear part, and is provided with a predetermined angle of attack θ in the counterclockwise direction with respect to the imaginary line in the fore-and-aft direction, while the starboard side rudder board 3 is positioned with its front part to the right of its rear part, and is provided with a predetermined angle of attack θ in the clockwise direction with respect to the imaginary line in the fore-and-aft direction. As a result, the port side rudder board 2 generates lift toward the left front side due to the rotating flow flowing out of the propeller 1, and the port side rudder board 2 generates lift toward the right front side due to the fore-and-aft components of these lifts, generating a propulsive force that makes the ship sail forward, and the port side rudder board 2 and starboard side rudder board 3 can recover the energy of the rotating flow and convert it into kinetic energy efficiently.

[0042] Also, as shown in Figure 5, the portions located below the left front rudder board 10 at the left inclined portion 14 of the left front rudder board 10 and the left rear rudder board 11 of the port side rudder board 2 are provided with a predetermined angle of attack θ in the counterclockwise direction with respect to a virtual line in the fore-and-aft direction, the portions located below the left front rudder board 10 at the left vertical portion 13 and left inclined portion 14 of the left rear rudder board 11 are provided along the virtual line in the fore-and-aft direction, the portions located below the right front rudder board 20 at the right inclined portion 24 of the right front rudder board 20 and the right rear rudder board 21 of the starboard side rudder board 3 are provided with a predetermined angle of attack θ in the clockwise direction with respect to a virtual line in the fore-and-aft direction, and the portions located below the right front rudder board 20 at the right vertical portion 23 and right inclined portion 24 of the right rear rudder board 21 can also be provided along a virtual line in the fore-and-aft direction. This makes it possible to prevent corrosion of the front part of the left inclined part 14 caused by cavitation when the left rudder stock 15 is rotated clockwise in a plan view to bring the front part of the left inclined part 14 closer to the propeller 1, and to prevent corrosion of the front part of the right inclined part 24 caused by cavitation when the right rudder stock 25 is rotated counterclockwise to bring the front part of the right inclined part 24 closer to the propeller 1. Note that Fig. 5 illustrates a form in which the angle of attack θ is set to 15 degrees.

[0043] As shown in Fig. 5, the left rudder stock 15 is provided at a position 30 to 35% of the longitudinal length of the port side rudder board 2 from the front end of the port side rudder board 2. The right rudder stock 25 is provided at a position 30 to 35% of the longitudinal length of the starboard side rudder board 3 from the front end of the starboard side rudder board 3. This makes the centers of load applied to the left rudder stock 15 and the port side rudder board 2 close to each other, so that the steering gear that rotates of the left rudder stock 15 can be made compact, and the centers of load applied to the right rudder stock 25 and the starboard side rudder board 3 close to each other, so that the steering gear that rotates of the right rudder stock 25 can be made compact.

[0044] In the longitudinal direction, the left rudder stock 15 is provided adjacent to the rear side of the longitudinal center line L of the propeller 1, and the front part of the left rudder stock 15 is provided extending forward beyond the longitudinal center line L of the propeller 1. Also, the right rudder stock 25 is provided adjacent to the rear side of the longitudinal center line L of the propeller 1, and the front part of the right rudder stock 25 is provided extending forward beyond the longitudinal center line L of the propeller 1. This makes it possible to prevent interference between the left rear rudder board 11 rotated by the left rudder stock 15 and the propeller 1, and to prevent interference between the right rear rudder board 21 rotated by the right rudder stock 25 and the propeller 1. Also, the high-speed water flow flowing into the propeller 1 and the high-speed rotating flow flowing out from the propeller 1 can be made to flow along the port side rudder board 2 and the starboard side rudder board 3, and a large lift can be generated on the port side rudder board 2 and the starboard side rudder board 3.

[0045] As shown in FIG. 6, when the steering wheel (not shown) on the bridge is operated from straight ahead to starboard, the left rudder stock 15 and the right rudder stock 25 rotate a predetermined angle, for example, 45 degrees, so that the left rear rudder board 11 rotates 45 degrees clockwise around the left rudder stock 15, and the right rear rudder board 21 rotates 45 degrees clockwise around the right rudder stock 25. On the other hand, when the steering wheel is operated from straight ahead to starboard, the left rudder stock 15 and the right rudder stock 25 rotate a predetermined angle, for example, 45 degrees counterclockwise, so that the left rear rudder board 11 rotates 45 degrees counterclockwise around the left rudder stock 15, and the right rear rudder board 21 rotates 45 degrees counterclockwise around the right rudder stock 25. The rotation angle of the left rudder stock 15 and the right rudder stock 25 when steering and the rotation angle of the left rudder stock 15 and the right rudder stock 25 when steering starboard can be arbitrarily set within the range of 30 to 60 degrees via the controller. FIG. 6 illustrates a steering device used in a coastal ship, in which the rotation angle between the left rudder stock 15 and the right rudder stock 25 is set to 45 degrees.

[0046] <Second steering device> Next, the second steering device will be described. Note that the same members and parts as those in the first steering device will be given the same reference numerals and the description thereof will be omitted.

[0047] As shown in Figures 7 to 9, the left front rudder plate 10 is formed to extend in the vertical direction, and its upper part is fixed to the lower part of the stern. In addition, a rectangular left convex part 10A is formed in the rear middle part of the left front rudder plate 10, which protrudes toward the left rear rudder plate 11 more than the rear upper part and the rear lower part.

[0048] The left rear rudder plate 11 is formed to extend in the vertical direction, and a rectangular left recess 11A is formed in the front middle portion of the left rear rudder plate 11, into which the left protrusion 10A is inserted.

[0049] The left rear rudder blade 11 is rotatably supported on the left convex part 10A via the left support shaft 12 and the left rudder stock 15, and the axis of the left support shaft 12 and the left rudder stock 15 are aligned when viewed from the axis of the left rudder stock 15. This allows the load of the left rear rudder blade 11 to be distributed and supported by the left front rudder blade 10 and the left rudder stock 15, preventing the shaft diameter of the left rudder stock 15 from becoming excessively thick.

[0050] The right front rudder plate 20 is formed to extend in the vertical direction, and its upper part is fixed to the lower part of the stern. In addition, a rectangular right convex part 20A is formed in the rear middle part of the right front rudder plate 20, which protrudes toward the right rear rudder plate 21 more than the rear upper part and the rear lower part.

[0051] The right rear rudder blade 21 is formed to extend in the vertical direction, and a rectangular right recess 21A is formed in the front middle portion of the right rear rudder blade 21, into which the right protrusion 20A is inserted.

[0052] The right rear rudder blade 21 is rotatably supported on the right convex part 20A via the right support shaft 22 and the right rudder stock 25, and the axis of the right support shaft 22 and the right rudder stock 25 are aligned when viewed from the axis of the right rudder stock 25. This allows the load of the right rear rudder blade 21 to be distributed and supported by the right front rudder blade 20 and the right rudder stock 25, preventing the shaft diameter of the right rudder stock 25 from becoming excessively thick.

[0053] In rear view, the left front rudder plate 10 and the left rear rudder plate 11 are provided at a predetermined distance to the left of the left end of the rotating periphery of the propeller 1, and the right front rudder plate 20 and the right rear rudder plate 21 are provided at a predetermined distance to the right of the right end of the rotating periphery of the propeller 1. This makes it possible to suppress corrosion due to cavitation on the right side of the left front rudder plate 10 and the left rear rudder plate 11 and the left side of the right front rudder plate 20 and the right rear rudder plate 21.

[0054] When viewed from the rear, it is preferable that the lower ends of the left front rudder blade 10 and the left rear rudder blade 11 and the lower ends of the right front rudder blade 20 and the right rear rudder blade 21 are positioned at the lower ends of the propeller 1's turning periphery.

[0055] In the case of a coastal ship, as shown in Fig. 8, it is preferable to position the lower ends of the left front rudder board 10 and the left rear rudder board 11 and the lower ends of the right front rudder board 20 and the right rear rudder board 21 below the lower end of the outer periphery of the propeller 1. This improves the turning performance of the ship and shortens the ship's vertical distance and turning circle. On the other hand, in the case of an ocean-going ship, it is preferable to position the lower ends of the left front rudder board 10 and the left rear rudder board 11 and the lower ends of the right front rudder board 20 and the right rear rudder board 21 above the lower end of the outer periphery of the propeller 1. This reduces the resistance of the left rear rudder board 11 and the right rear rudder board 21, allowing the ship to sail efficiently.

[0056] <Third Steering Device> Next, the third steering device will be described. As shown in Fig. 10, a port side rudder blade 2 is provided on the port side of a ship's propeller 1, and a starboard side rudder blade 3 is provided on the starboard side.

[0057] The port side rudder board 2 is formed of the left front rudder board 10 located at the front and the left rear rudder board 11 provided on the rear side of the left front rudder board 10. The left rear rudder board 11 is formed of the first left rear rudder board 31 forming the front part of the first left rear rudder board 31 and the flap-shaped second left rear rudder board 32 forming the rear part of the first left rear rudder board 31. The left front rudder board 10 is formed to extend in the vertical direction to the left lower part of the propeller 1 at the stern of the ship, and the upper part of the left front rudder board 10 is fixed to the lower part of the stern of the ship. In addition, in a side view, the length in the longitudinal direction of the second left rear rudder board 32 is formed to be approximately half the length in the longitudinal direction of the first left rear rudder board 31.

[0058] The starboard side rudder board 3 is formed of the right front rudder board 20 located at the front and the right rear rudder board 21 provided on the rear side of the right front rudder board 20. The right rear rudder board 21 is formed of the first right rear rudder board 41 forming the front part of the first right rear rudder board 41 and the flap-shaped second right rear rudder board 42 forming the rear part of the first right rear rudder board 41. The right front rudder board 20 is formed extending in the vertical direction to the right lower part of the propeller 1 at the stern of the ship, and the upper part of the right front rudder board 20 is fixed to the lower part of the stern of the ship. In addition, in a side view, the length in the longitudinal direction of the second left rear rudder board 32 is formed to be approximately half the length in the longitudinal direction of the first left rear rudder board 31.

[0059] The front part of the first left rear rudder plate 31 is supported by the left rudder stock 15 extending in the vertical direction provided on the rear side of the left front rudder plate 10, and the front lower part of the first left rear rudder plate 31 is supported rotatably on the rear lower part of the left front rudder plate 10, forming a so-called semi-balanced rudder. This makes it possible to prevent the shaft diameter of the left rudder stock 15 supporting the first left rear rudder plate 31 from becoming excessively large.

[0060] The front part of the second left rear rudder board 32 is rotatably supported on the left flap shaft 34 extending in the vertical direction provided at the rear of the first left rear rudder board 31, the front upper part of the second left rear rudder board 32 is supported on the rear upper part of the first left rear rudder board 31, and the front lower part of the second left rear rudder board 32 is supported on the rear lower part of the first left rear rudder board 31, forming a so-called balanced rudder. This makes it possible to prevent the shaft diameter of the left flap shaft 34 supporting the second left rear rudder board 32 from becoming excessively large.

[0061] The longitudinal length of the first left rear rudder blade 31 is approximately 2.5 times the longitudinal length of the left front rudder blade 10, and the longitudinal length of the second left rear rudder blade 32 is approximately the same as the longitudinal length of the first left rear rudder blade 31. As a result, the lift generated by the port side rudder blade 2 acts on approximately the center of the left rudder stock 15, so that the driving force driving the left rudder stock 15 can be reduced.

[0062] The front part of the first right rear rudder plate 41 is supported by the right rudder shaft 25 extending in the vertical direction provided on the rear side of the right front rudder plate 20, and the front lower part of the first right rear rudder plate 41 is rotatably supported by the rear lower part of the right front rudder plate 20, forming a so-called semi-balanced rudder. This makes it possible to prevent the shaft diameter of the right rudder shaft 25 supporting the first right rear rudder plate 41 from becoming excessively large.

[0063] The front part of the second right rear rudder board 42 is supported by the right flap shaft 44 extending in the vertical direction provided at the rear of the first right rear rudder board 41, the front upper part of the second right rear rudder board 42 is supported by the rear upper part of the first right rear rudder board 41, and the front lower part of the second right rear rudder board 42 is supported by the rear lower part of the first right rear rudder board 41, forming a so-called balanced rudder. This makes it possible to prevent the shaft diameter of the right flap shaft 44 supporting the second right rear rudder board 42 from becoming excessively large.

[0064] The longitudinal length of the first right rear rudder blade 41 is approximately 2.5 times the longitudinal length of the right front rudder blade 20, and the longitudinal length of the second right rear rudder blade 42 is approximately the same as the longitudinal length of the first right rear rudder blade 41. As a result, the lift generated by the starboard side rudder blade 3 acts on approximately the center of the right rudder stock 25, so that the driving force driving the right rudder stock 25 can be reduced.

[0065] The upper part of the left rudder stock 15 extends into the steering room, and the left rudder (not shown) extending in the left-right direction is fixed to the upper part of the left rudder stock 15, and a hydraulically driven cylinder is connected to each side of the left rudder. As a result, when the ship is sailing straight, the rods of the pair of cylinders can be moved to the middle position to position the longitudinal direction of the first left rear rudder board 31 along the fore-aft direction. Also, when the ship's rudder is operated to the left to turn the ship's course, the rod of the left cylinder can be pulled out to the extended position and the rod of the right cylinder can be retracted to the retracted position, and the left rudder stock 15 can be rotated clockwise to position the rear part of the first left rear rudder board 31 to the left of the front part of the first left rear rudder board 31. On the other hand, when the ship's rudder is turned to starboard to turn the ship's course to the right, the rod of the left cylinder is retracted to the retracted position and the rod of the right cylinder is pulled out to the extended position to rotate the left rudder shaft 15 counterclockwise, so that the rear of the first left rear rudder board 31 can be positioned to the right of the front of the first left rear rudder board 31.

[0066] When the ship's rudder is turned to starboard to turn the ship to the left, the port rudder stock 15 rotates 45 degrees clockwise, and the intersection angle between the longitudinal direction of the first left rear rudder board 31 and the acute angle between the imaginary line in the fore-aft direction and the longitudinal direction of the first left rear rudder board 31 becomes 45 degrees clockwise. On the other hand, when the ship's rudder is turned to starboard to turn the ship to the right, the port rudder stock 15 rotates 45 degrees counterclockwise, and the intersection angle between the longitudinal direction of the first left rear rudder board 31 and the acute angle between the imaginary line in the fore-aft direction and the longitudinal direction of the first left rear rudder board 31 becomes 45 degrees counterclockwise.

[0067] The upper part of the right rudder stock 25 extends into the steering room, and the right rudder (not shown) extending in the left-right direction is fixed to the upper part of the right rudder stock 25, and a hydraulically driven cylinder is connected to each side of the right rudder. As a result, when the ship is sailing straight, the rods of the pair of cylinders can be moved to the middle position to position the longitudinal direction of the first right rear rudder board 41 along the fore-aft direction. Also, when the ship's rudder is operated to the left to turn the ship's course, the rod of the left cylinder can be pulled out to the extended position and the rod of the right cylinder can be retracted to the retracted position, and the right rudder stock 25 can be rotated clockwise to position the rear part of the first right rear rudder board 41 to the left of the front part of the first right rear rudder board 41. On the other hand, when the ship's rudder is turned to starboard to turn the ship's course to the right, the rod of the left cylinder is retracted to the retracted position and the rod of the right cylinder is pulled out to the extended position to rotate the right rudder shaft 25 counterclockwise, so that the rear of the first right rear rudder board 41 can be positioned to the right of the front of the first right rear rudder board 41.

[0068] When the ship's rudder is turned to starboard to turn the ship to the left, the starboard rudder stock 25 rotates 45 degrees clockwise, and the intersection angle between the longitudinal direction of the first starboard rudder board 41 and the acute angle between the longitudinal imaginary line and the acute angle between the longitudinal imaginary line and the acute angle between the longitudinal imaginary line and the acute angle between the longitudinal imaginary line and the acute angle between the longitudinal imaginary line and the acute angle between the longitudinal imaginary line and the acute angle between the longitudinal imaginary line and the acute angle.

[0069] 11 and 12, a left support shaft 35 extending in the vertical direction is provided on the rear side of the left rudder stock 15, and an upper part of the left support shaft 35 is fixed to the lower left side of the propeller 1 at the stern of the boat. Note that, in a side view, the left support shaft 35 is provided forward of the left flap shaft 34.

[0070] The left and right engagement members 36, which have through holes extending in the fore-and-aft direction, are provided at the upper rear part of the second left rear rudder plate 32. The lower part of the left support shaft 35 and the left and right engagement members 36 are connected by a left connecting member 38. The front part of the left connecting member 38 is formed into a cylindrical part so as to be rotatably fitted onto the left support shaft 35, and the rear part of the left connecting member 38 is formed into a round bar shape so as to be able to slide in the fore-and-aft direction through the through hole.

[0071] In a side view, the length in the front-rear direction of the left and right engaging members 36 is formed to be approximately the same as the length in the front-rear direction of the upper part of the second left rear rudder plate 32. In addition, it is preferable to provide a slide bearing inside the left and right engaging members 36 and a bearing in the front part of the left connecting member 38. This makes it possible to reduce the weight of the second left rear rudder plate 32 and to smoothly rotate the second left rear rudder plate 32 around the left flap shaft 34. In addition, it is possible to prevent the connection between the lower part of the left support shaft 35 and the left and right engaging members 36 from coming loose.

[0072] In a side view, the length between the center of the left support shaft 35 and the rear end of the second left rear rudder board 32 is shorter than the length between the center of the left rudder stock 15 and the rear end of the second left rear rudder board 32 when the ship is traveling straight ahead. As a result, when the ship's rudder is operated to the starboard rudder to turn the ship's course to the left, the left rudder stock 15 is rotated clockwise to position the rear of the first left rear rudder board 31 to the left of the front of the first left rear rudder board 31, and the rear of the second left rear rudder board 32 to the left of the front of the second left rear rudder board 32. On the other hand, when the ship's rudder is operated to the starboard rudder to turn the ship's course to the right, the left rudder stock 15 is rotated counterclockwise to position the rear of the first left rear rudder board 31 to the right of the front of the first left rear rudder board 31, and the rear of the second left rear rudder board 32 to the right of the front of the second left rear rudder board 32.

[0073] In this embodiment, when the ship's rudder is turned to the starboard rudder to turn the ship's course to the left, the left rudder stock 15 rotates 45 degrees clockwise, the intersection angle of the first left rear rudder board 31's longitudinal direction and the acute angle of the imaginary line in the longitudinal direction becomes 45 degrees clockwise, and the intersection angle of the second left rear rudder board 32's longitudinal direction and the imaginary line in the longitudinal direction becomes 90 degrees. That is, the second left rear rudder board 32 rotates 45 degrees clockwise more than the first left rear rudder board 31. On the other hand, when the ship's rudder is turned to the starboard rudder to turn the ship's course to the right, the left rudder stock 15 rotates 45 degrees counterclockwise, the intersection angle of the first left rear rudder board 31's longitudinal direction and the acute angle of the imaginary line in the longitudinal direction becomes 45 degrees counterclockwise, and the intersection angle of the second left rear rudder board 32's longitudinal direction and the imaginary line in the longitudinal direction becomes 90 degrees. That is, the second left rear rudder blade 32 rotates 45 degrees more counterclockwise than the first left rear rudder blade 31. This forms a large camber curve on the port side rudder blade 2, which can generate a large lift and reduce the turning radius of the ship.

[0074] A right support shaft 45 extending in the vertical direction is provided on the rear side of the right rudder stock 25, and an upper part of the right support shaft 45 is fixed to the lower right side of the propeller 1 at the stern of the ship. Note that, in a side view, the right support shaft 45 is provided forward of the right flap shaft 44.

[0075] The right and left engaging members 46, which have a through hole extending in the fore-and-aft direction, are provided on the upper rear side of the second right rear rudder plate 42. The lower part of the right support shaft 45 and the right and left engaging members 46 are connected by a right connecting member 48. The front part of the right connecting member 48 is formed into a cylindrical part so as to be rotatably fitted onto the right support shaft 45, and the rear part of the right connecting member 48 is formed into a round bar shape so as to be able to slide in the through hole in the fore-and-aft direction.

[0076] In side view, the length in the front-rear direction of the right and right engaging members 46 is formed to be approximately the same as the length in the front-rear direction of the upper part of the second right rear rudder plate 42. In addition, it is preferable to provide a slide bearing inside the right and right engaging members 46 and a bearing in the front part of the right connecting member 48. This makes it possible to reduce the weight of the second right rear rudder plate 42 and to smoothly rotate the second right rear rudder plate 42 around the right flap shaft 44. It is possible to prevent the connection between the lower part of the right support shaft 45 and the right and right engaging members 46 from coming loose.

[0077] In a side view, the length between the center of the right support shaft 45 and the rear end of the second right rear rudder board 42 is shorter than the length between the center of the right rudder stock 25 and the rear end of the second right rear rudder board 42 when the ship is traveling straight ahead. As a result, when the ship's rudder is operated to the starboard rudder to turn the ship's course to the left, the right rudder stock 25 is rotated clockwise to position the rear of the first right rear rudder board 41 to the left of the front of the first right rear rudder board 41, and the rear of the second right rear rudder board 42 to the left of the front of the second right rear rudder board 42. On the other hand, when the ship's rudder is operated to the starboard rudder to turn the ship's course to the right, the right rudder stock 25 is rotated counterclockwise to position the rear of the first right rear rudder board 41 to the right of the front of the first right rear rudder board 41, and the rear of the second right rear rudder board 42 to the right of the front of the second right rear rudder board 42.

[0078] In this embodiment, when the ship's rudder is turned to the left by operating the rudder to the starboard rudder, the right rudder stock 25 rotates 45 degrees clockwise, the intersection angle of the first right rear rudder board 41 and the acute angle of the imaginary line of the longitudinal direction and the longitudinal direction of the second right rear rudder board 42 becomes 45 degrees clockwise, and the intersection angle of the imaginary line of the longitudinal direction and the longitudinal direction of the second right rear rudder board 42 becomes 90 degrees. That is, the second right rear rudder board 42 rotates 45 degrees clockwise more than the first right rear rudder board 41. On the other hand, when the ship's rudder is turned to the starboard rudder to turn the ship to the right, the right rudder stock 25 rotates 45 degrees counterclockwise, the intersection angle of the first right rear rudder board 41 and the acute angle of the imaginary line of the longitudinal direction and the longitudinal direction of the second right rear rudder board 42 becomes 90 degrees. That is, the second starboard rear rudder board 42 rotates 45 degrees counterclockwise more than the first starboard rear rudder board 41. This forms a large camber curve on the port side rudder board 2, which can generate a large lift and reduce the turning radius of the ship.

[0079] In this embodiment, the longitudinal direction of the left front rudder plate 10 and the right front rudder plate 20 is set along the front-rear direction, but the front part of the left front rudder plate 10 can be positioned to the left side, and the front part of the right front rudder plate 20 can be positioned to the right side. This allows the left front rudder plate 10 and the right front rudder plate 20 to generate lift when the ship is sailing straight.

[0080] In this embodiment, the first left rear rudder plate 31, when viewed from the left rudder stock 15 axis, rotates 45 degrees clockwise around the left rudder stock 15 and 45 degrees counterclockwise, and the first right rear rudder plate 41, when viewed from the right rudder stock 25 axis, rotates 45 degrees clockwise around the right rudder stock 25 and 45 degrees counterclockwise, but the first left rear rudder plate 31, when viewed from the left rudder stock 15 axis, can also be rotated 40 degrees clockwise around the left rudder stock 15 and 30 degrees counterclockwise, and the first right rear rudder plate 41, when viewed from the right rudder stock 25 axis, can also be rotated 30 degrees clockwise around the right rudder stock 25 and 40 degrees counterclockwise. The flow of water from the propeller 1 toward the first left rear rudder board 31 and the first right rear rudder board 41 can be efficiently directed rearward between the first left rear rudder board 31 and the first right rear rudder board 41, thereby further improving the turning performance of the ship. [Industrial Applicability]

[0081] The present invention can be applied to a steering device of a ship. [Explanation of symbols]

[0082] 1 Propeller 2 Port side rudder 3 Starboard Rudder 10 Left front rudder plate 11 Left rear rudder 13 Left vertical section 14 Left slope 15 Left rudder axis 16 Left connecting member 20 Right front rudder plate 21 Right rear rudder plate 23 Right vertical part 24 Right slope 25 Right rudder axle 26 Right connecting member 31 1st left rear rudder plate 32 2nd left rear rudder plate 34 Left flap axis 35 Left support shaft 38 Left connecting member 41 1st right rear rudder plate 42 2nd right rear rudder plate 44 Right flap axis 45 Right support shaft 48 Right connecting member L center line

Claims

1. In a steering device in which a port side rudder board is arranged on the left side of a ship's propeller and a starboard side rudder board is arranged on the right side of the propeller, The port side rudder board is formed by a left front rudder board fixed to the bottom of the ship and a left rear rudder board provided on the rear side of the left front rudder board, and the left rear rudder board is formed by a first left rear rudder board at the front and a second left rear rudder board provided on the rear side of the rear part of the first left rear rudder board, The starboard side rudder board is formed by a right front rudder board fixed to the bottom of the ship and a right rear rudder board provided on the rear side of the right front rudder board, and the right rear rudder board is formed by a first right rear rudder board at the front and a second right rear rudder board provided on the rear side of the rear part of the first right rear rudder board, The front portion of the first left rear rudder plate is rotatably fixed to a left rudder shaft extending in the up-down direction to the left of the propeller, The front part of the second left rear rudder plate is rotatably fixed to a left flap shaft extending in the vertical direction at the rear part of the first left rear rudder plate, In a side view, a left support shaft extending in the vertical direction is provided between the left rudder shaft and the left flap shaft, The upper part of the left support shaft is fixed to the bottom of the ship, A left engaging member having a through hole is provided on the upper part of the second left rear rudder plate, and the left support shaft and the left engaging member are connected by a left connecting member; The front portion of the first right rear rudder plate is rotatably fixed to a right rudder shaft extending in the up-down direction to the right of the propeller, The front part of the second right rear rudder plate is rotatably fixed to a right flap shaft extending vertically to the rear part of the first right rear rudder plate; When viewed from the side, a right support shaft extending in the vertical direction is provided between the right rudder shaft and the right flap shaft, The upper part of the right support shaft is fixed to the bottom of the ship, A right engaging member having a through hole is provided on the upper part of the second right rear rudder plate, and the right support shaft and the right engaging member are connected by a right connecting member; The left rear rudder plate is formed by a left vertical portion provided on the rear side of the left front rudder plate and a left inclined portion extending downward to the right from the lower part of the left vertical portion, The right rear rudder plate is formed by a right vertical portion provided on the rear side of the right front rudder plate and a right inclined portion extending downward to the left from the lower part of the right vertical portion, In a side view, the left inclined portion extends from the front of the left front rudder plate to the rear of the left vertical portion, and the right inclined portion extends from the front of the right front rudder plate to the rear of the right vertical portion; When viewed from the rear, lower ends of the left inclined portion and the right inclined portion are positioned at a lower end of a rotating outer periphery of the propeller, The right surface of the left front rudder plate and the lower part of the stern are connected by a left connecting member, The left surface of the right front rudder plate and the lower part of the stern are connected by a right connecting member, A steering device characterized in that, in a rear view, the left connecting member is provided parallel to the right inclined portion, and the right connecting member is provided parallel to the left inclined portion.

2. When viewed from the axis of the left rudder stock, the first left rear rudder plate rotates 45 degrees in the clockwise and counterclockwise directions, When viewed from the axis of the left flap shaft, the second left rear rudder plate rotates 45 degrees in the clockwise and counterclockwise directions, When viewed from the axis of the right rudder stock, the first right rear rudder plate rotates 45 degrees in the clockwise and counterclockwise directions, 2. A steering device according to claim 1, wherein the second right rear rudder plate rotates 45 degrees in a clockwise and counterclockwise direction when viewed from the axis of the right flap shaft.

3. 3. A steering device according to claim 1 or 2, wherein the front portion of the left front rudder plate is positioned forward and to the left of the rear portion, and the front portion of the right front rudder plate is positioned forward and to the right of the rear portion.

4. A steering device as described in any one of claims 1 to 3, wherein, when viewed from the left side, the fore-and-aft length of the second left rear rudder blade is approximately half the fore-and-aft length of the first left rear rudder blade, and the fore-and-aft length of the second right rear rudder blade is approximately half the fore-and-aft length of the first right rear rudder blade.

5. The left rear rudder plate is rotatably supported by the rear part of the left front rudder plate and a left rudder shaft extending in the vertical direction fixed to the left rear rudder plate, The right rear rudder plate is rotatably supported by the rear part of the right front rudder plate and a right rudder shaft extending in the vertical direction fixed to the right rear rudder plate, A steering device according to any one of claims 1 to 4, wherein the lower ends of the port side rudder blade and the starboard side rudder blade are positioned at the lower end of the rotating outer periphery of the propeller when viewed from behind.

6. 6. The steering device according to claim 1, wherein, in a plan view, the left rudder stock and the right rudder stock are provided adjacent to the rear side of the center line of the propeller in the fore-and-aft direction.

Images