JPS623038B2 - - 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 of 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 located 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 a 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 providing a wave-dissipating object independently on the main hull,
It is an object of the present invention to provide a device that can prevent the generation of excessive stress on a portion where a wave-dissipating object is attached to a main hull.

For this reason, the hull resistance reducing device of the present invention is provided with a wave-dissipating object for reducing hull resistance at a position spaced rearward from the rear end of the main hull at the load waterline in the stern, and the wave-dissipating object is provided with a wave-dissipating object for reducing the hull resistance. In order to reduce hull resistance due to mutual interference between waves and waves generated from the stern of the main hull, the upper support arm and the lower support arm are arranged so that at least a part of the waves exists below the load waterline. The wave-dissipating object is attached to the main hull via a.

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 portion thereof, and FIG. In Figure 5, the same reference numerals as those already described indicate substantially similar parts.

Further, reference numeral 16 indicates a seawater tank, 17a and 17b indicate an upper support arm and a lower support arm, respectively, 19 indicates a wave-dissipating object, and 19a and 19a' indicate outer plates of the wave-dissipating object.

As shown in these figures, the rear end 11 of the main hull 1
A wave-dissipating object 19 is provided at a position spaced rearward from the upper support arm 17 .
a and the lower support arm 17b below it.

The wave-dissipating object 19 is provided 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. It may also be a rotating body with .

A seawater tank 16 is provided inside the vanishing object 19, and is connected to a seawater pump (not shown) in the main hull 1 by a conduit (not shown) provided in an upper support arm 17a and a lower support arm 17b. has been done.

The seawater pump injects and drains seawater into the seawater tank 16 inside the wave-dissipating object 19. Alternatively, an inlet/drain conduit that opens below the water surface is provided at the bottom of the seawater tank 16, and
An air venting conduit may be provided at the top of the tank 16 that opens above the water surface, and water may be poured by gravity according to changes in the draft.

In this way, since the wave-dissipating object 19 is provided independently behind the main hull 1, even when the ship turns, the water flow 14 at the stern (see FIG. 3) is directed to the upper support arm that supports the wave-dissipating object 19. 17a and the lower support arm 17b. Therefore, the water flow 14 can flow around both the front and rear sides of the wave-dissipating object 19, thereby causing damage to the wave-dissipating object 19 itself and the upper support arm 17.
a and the lower support arm 17b are no longer subject to large lateral resistance. Therefore, each support arm 17a, 17b, each support arm 17a,
Excessive stress will not be generated at the connection between the main hull 17b and the main hull 1, and damage to these parts will not occur.

In addition, by appropriately pouring seawater into the seawater tank 16, the weight and buoyancy of the wave-dissipating object 19 and each support arm 17a, 17b can be balanced regardless of the draft. 17a, 17b and each support arm 17
It is possible to sufficiently prevent excessive stress from being generated at the connection between a, 17b and the main hull 1.

The action of the wave-dissipating object 19 in the device of the invention 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. 9, the wave-dissipating object 19 in the device of the present invention is provided independently from the main hull 1 via the upper support arm 17a and the lower support arm 17b.

Therefore, the hull resistance reduction effect is also greater in the case of the present invention than in the conventional technology, and conversely, when the hull resistance reduction effect is made the same, the case of the present invention has a smaller wave dissipating shape. There is an advantage that the object is only 19.

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 at a position spaced rearward from the rear end of the main hull at the load waterline, and this wave-dissipating object In order to reduce hull resistance due to mutual interference between waves generated from the wave-dissipating object and waves generated from the stern of the main hull, the upper support The simple configuration in which the wave-dissipating object is attached to the main hull via an arm and a lower support arm prevents the generation of excessive stress at the connection between the wave-dissipating object and the main hull, which has been a problem in the past. It becomes possible to
It is also possible to downsize the wave-dissipating object itself, etc.
Various advantages can be obtained.

[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 stern side view thereof, and FIG. 5 is a horizontal cross section taken along the - line in FIG. 4. It is a diagram. 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, 10a... Arbitrary waterline, 11... Rear end of main hull above load waterline, 12... Hull center line, 13... Ship's turning trajectory, 14... Stern Water flow, 15a... Upper stun frame, 15b... Lower stun frame, 16
... Seawater tank, 17a ... Upper support arm, 1
7b...Lower support arm, 19...Wave dissipating object, 1
9a, 19a'... Outer plate of the wave-dissipating object, l... Projection amount, O... Center point of the ship, P... Turning center of the ship.

Claims (1)

[Scope of Claims] 1. A wave-dissipating object for reducing hull resistance is provided at the stern of the ship at a position spaced rearward from the rear end of the main hull's load waterline, and this wave-dissipating object dissipates waves generated from the wave-dissipating object and the main hull. In order to reduce hull resistance due to mutual interference with waves generated from the stern of the hull, at least a portion of the hull is located below the load waterline, and the above-mentioned A hull resistance reducing device characterized in that a wave-dissipating object is attached to the main hull. 2 A seawater tank is provided inside the wave-dissipating object,
The hull resistance reduction device according to claim 1, wherein a seawater pump communicating with the seawater tank via a conduit is installed in the main hull. 3 A seawater tank is provided inside the wave-dissipating object,
The hull according to claim 1, wherein a water filling conduit that opens below the water surface is provided at the bottom of the seawater tank, and an air venting conduit that opens above the water surface is provided at the top of the seawater tank. Resistance reduction device.