JPS623039B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a device for reducing resistance experienced by a ship during navigation, and particularly to a device for reducing resistance to a ship's hull suitable for use in a high-speed ship.

Conventional hull resistance reducing devices include those shown in Figures 1 and 2, with Figure 1 being a side view thereof and Figure 2 being a sectional view taken along the - line in Figure 1.
FIG. 3 is a plan view showing a state in which a ship equipped with the above device is turning.

In Figures 1 to 3, 1 is the main hull, 2 is the rudder, 3 is the propeller, 4 is the stern bossing, 5 is the propeller shaft, 6 is the propeller cap, 7 is the upper rudder support member, 8 is the rudder stem, 9 is a protrusion for reducing hull resistance;
9a and 9a' are the outer plates of the protrusion 9, 9b and 9b' are reinforcing members for the protrusion 9, 10 is the load water line, 10a is an arbitrary water line, 11 is the rear end of the main hull on the load water line, and 12 is the hull 13 is the turning trajectory of the ship, 14 is the water flow at the stern, 15a is the upper stern frame, 15b is the lower stern frame, l is the amount of protrusion, 0 is the center point of the ship, and P is the turning center of the ship.

As shown in FIGS. 1 and 2, a protrusion 9 as a wave-dissipating object is provided behind the rear end 11 of the main hull 1 above the load waterline 10, and a part of it is positioned above the load waterline 10. At the same time, by locating the remainder below the load waterline 10, waves generated from the stern of the main hull 1 and waves generated from the protrusion 9 can interfere with each other, thereby reducing hull resistance. Are known.

However, if the protrusion 9 as a wave-dissipating object is made to protrude further rearward than the rear end 11 of the main hull 1 by a protrusion amount l, not only will this cause problems during berthing and unberthing work, but the waves will also disturb the protrusion. 9 and generates excessive stress at the connection part with the main hull 1, which may cause damage.

Also, as shown in Figure 3, when the ship turns, the stern water flow 14 flows outside the turning circle.
Since it collides with the protrusion 9, it similarly generates excessive stress at the connection part with the main hull 1, which has the disadvantage of causing damage.

Furthermore, general ships do not always sail only at the loaded waterline 10, and the waterline changes depending on the loading situation, so the buoyancy of the protrusion 9 changes due to such changes in the waterline, and the weight of the protrusion 9 changes. If the buoyancy becomes too large compared to the buoyancy, there is a problem in that excessive stress is generated at the connection between the protrusion 9 and the main hull 1.

Furthermore, as a result of providing the protrusion 9 behind the rudder 2 that has the effect of blocking the water flow 14 at the stern when turning, the directional stability of the ship becomes excessive, resulting in a decrease in maneuverability (deterioration of rudder effectiveness). This also causes the problem that it becomes difficult for the ship to turn even if the ship is steered.

The present invention attempts to solve the above-mentioned problems in conventional hull resistance reduction devices, and by reducing the force exerted by the wave-dissipating object during turning, it aims to improve the strength and also improve the wave-dissipating performance. It is an object of the present invention to provide a device that can further improve

For this reason, the hull resistance reducing device of the present invention is provided with a wave-dissipating object for reducing hull resistance, separate from the rudder, at a position spaced rearward from the rear end of the main hull at the load waterline in the stern, and this wave-dissipating object has at least It is characterized in that it is formed to have a symmetrical streamlined shape and is rotatably supported around a vertical axis by an upper support arm and a lower support arm that protrude from the main hull.

Hereinafter, a hull resistance reducing device as an embodiment of the present invention will be explained with reference to the drawings. Fig. 4 is a side view of the stern part thereof, and Fig. 5 is a top view of the stern part thereof. The same reference numerals indicate substantially similar parts.

17a is an upper support arm, 17b is a lower support arm, 18a is an upper vertical axis, 18b is a lower vertical axis, 19 is a wave-dissipating object, 20 is the center line of the rudder when the rudder angle is set, and 21 is the hull The center line of the wave-dissipating object 19 at an angle from the center line 12, 22
is the rotation axis of the wave-dissipating object 19, δ is the rudder angle, θ is the angle between the center line 21 of the wave-dissipating object 19 and the hull center line 12, and 1a is the water line at the full draft.

As shown in FIGS. 4 and 5, the rear end 11 of the main hull 1
A wave-dissipating object 19 is provided at a position spaced backward from the wave-dissipating object 19, and an upper vertical shaft 18a and a lower vertical shaft 18b are rotated in the same direction in front of the point of action of the lateral drag of this wave-dissipating object 19. Provided to be located on the axis 22, both vertical shafts 18a, 18
b is rotatably held by an upper support arm 17a and a lower support arm 17b fixedly protruding from the main hull 1.

The wave-dissipating object 19 is arranged so that at least a part of it is under the water surface, and its shape is a symmetrical streamlined shape with a bulge in the center, but it simply has an axis in the front and rear horizontal directions. A streamlined rotating body may also be used.

In this way, since the wave-dissipating object 19 is independently provided behind the main hull 1, the water flow 14 can flow around both the front and rear sides of the wave-dissipating object 19 even when the ship is turning. The wave-breaking object 19 is configured to be rotatable around the vertical axes 18a, 18b, and since the vertical axes 18a, 18b are located in front of the point of action of the lateral drag on the wave-breaking object 19, the wave-breaking object 19 can be freely rotated around the vertical axes 18a, 18b. The object 19 is oriented in the direction of the water flow 14 as shown in FIG. 5, so that the lateral drag forces acting on the upper support arm 17a and the lower support arm 17b during the pivot are significantly reduced. Therefore, it is possible to prevent excessive stress from being generated in each of the support arms 17a, 17b and the connection portion between each of the support arms 17a, 17b and the main hull 1, causing damage to these parts. This has the advantage of improving the ship's turning performance compared to the case of a wave-dissipating object.

Note that the action of the wave-dissipating object 19 in this embodiment is as follows:
Similar to the effect of the protrusion 9 in the conventional technology, the wave-dissipating object 1
The waves generated from the main hull 1 are made to interfere with the waves generated from the stern of the main hull 1, thereby reducing the hull resistance. The wave-dissipating object 19 of this embodiment, which is provided independently from the main hull 1, is larger than the wave-dissipating object 9.

Therefore, the effect of reducing the hull resistance is also greater than that of the prior art.Conversely, if the effect of reducing the hull resistance is the same, the present invention has the advantage of requiring a smaller wave-dissipating object 19.

In the embodiment described above, the wave-dissipating object 19 is aligned with the vertical axis 18
a, 18b, but the rotation of the wave-dissipating object 19 is controlled by the rudder 2 of the main hull 1.
In this case, when the rudder 2 takes a rudder angle δ, the wave-dissipating object 19 also rotates by an angle θ in the same direction as the rudder 2. configured. Note that the magnitude of the angle θ is less than or equal to the magnitude of the angle δ.

With the above configuration, the wave-breaking object 19 can be reliably set at the angle θ, so the lateral drag acting on the wave-breaking object 19 during turning can be reduced, and the fixed wave-breaking object 19 can be made to take the angle θ. The ship's turning performance is improved compared to

Furthermore, even when the ship is turning, when the rudder angle δ returns to zero, the angle θ of the wave-dissipating object 19 also becomes zero, and as a result, the lateral drag of the wave-dissipating object 19 increases; The ship's course-keeping performance is improved, and the ship is able to stop its turning motion and go straight ahead more quickly.In conjunction with the aforementioned improvement in turning performance, compared to the case of a fixed wave-dissipating object, The ship's maneuverability can be greatly improved.

As described in detail above, according to the hull resistance reducing device of the present invention, a wave-dissipating object for reducing hull resistance is provided separately from the rudder at a position spaced apart rearward from the rear end of the main hull at the load waterline. A simple structure in which the wave object is formed to have at least a symmetrical streamlined shape, and is rotatably supported around a vertical axis by an upper support arm and a lower support arm protruding from the main hull. With this configuration, it is possible to prevent the generation of excessive stress at the connection part of the wave-dissipating object with the main hull, which has been a problem in the past, and it is also possible to downsize the wave-dissipating object itself. This provides the following advantages.

[Brief explanation of the drawing]

Figure 1 is a stern side view showing a conventional hull resistance reduction device, Figure 2 is a horizontal sectional view taken along the - line in Figure 1, and Figure 3 is a plan view showing a turning state of a vessel equipped with a hull resistance reduction device. 4 and 5 show a hull resistance reducing device as an embodiment of the present invention, FIG. 4 is a side view of the stern, and FIG. 5 is a top view of the stern. 1... Main hull, 2... Rudder, 3... Propeller, 4
... Stern botting, 5 ... Propeller shaft, 6 ...
Propeller cap, 7... Upper rudder support member, 8...
... Rudder handle, 10 ... Load waterline, 11 ... Rear end of main hull above load waterline, 12 ... Hull center line, 13 ... Turning trajectory of ship, 14 ... Water flow at stern, 15a ... Upper stand Frame, 15b...
Lower stern frame, 17a... Upper support arm, 17b... Lower support arm, 18a... Upper vertical axis, 18b... Lower vertical axis, 19... Wave dissipating object, 20... Center line of rudder, 21... Center line of the wave-dissipating object, 22...Rotation axis of the wave-dissipating object, l...Protrusion amount, O...Hull center point, P...Ship's turning center, δ
...Rudder angle, θ...Angle between the center line of the wave-dissipating object and the center line of the hull.

Claims (1)

[Scope of Claims] 1. A wave-dissipating object for reducing hull resistance is provided separately from the rudder at a position spaced rearward from the rear end of the load waterline of the main hull at the stern, and this wave-dissipating object at least maintains a symmetrical flow. A hull resistance reducing device characterized in that the device is linearly formed and rotatably supported around a vertical axis by an upper support arm and a lower support arm protruding from the main hull. 2. The hull resistance reducing device according to claim 1, wherein the wave-dissipating object is rotated in conjunction with a steering machine for the rudder of the main hull.