JPH06298159A - Bow spray decereasing device for ship - Google Patents

Abstract

PURPOSE:To moderate the wave making phenomenon and spray phenomenon by limiting the rising height of wave generated on the bow part along the surface of the hull by air downward injected from air nozzles. CONSTITUTION:Air injecting nozzles 3 are connected from an air compressor 4 in a hull 1 with pipes 5 and provided at optional intervals in the longitudinal direction along the surface of the hull 1, over the designed load draft line LWL. When the hull 1 is advancingly navigated, a wave is generated at the bow part. The generated wave is apt to rise along the surface of the hull 1 and bow material 2, and rise of the wave is weakened by downward injecting compressed air from the air injecting nozzles 3. Hereby, wave making resistance and spray pheomenon are weakened, and hence increase of hull 1 resistance can be reduced.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a bow spray reducing device for a ship.

[0002]

2. Description of the Related Art Conventionally, as shown in FIG.
As shown in the side view, the horizontal sectional view and the transverse sectional view, generally, the bow 2 is configured to project forward above the planned full load line LWL. In this type of bow, as shown in the side view and front view of FIG. 13, a wave is created in the bow portion, which is the hull 1 and the bow material 2
Rises along the surface of the ship, and at that time, a part of the ship peels off from the hull 1 into a spray and drops onto the water surface.

[0003]

As described above, the waves generated at the bow rise along the surface of the hull and partly fall, so that the hull resistance increases and the propulsion performance deteriorates. This phenomenon is remarkable as the flare of the bow is larger,
In particular, a large deck area such as a car ferry boat or a car carrier is required, and this is a big problem for ship types with a relatively high ship speed of 20 knots or more. There is a demand for countermeasures using this device.

The present invention has been proposed in view of the above circumstances, and an object thereof is to provide an economical ship bow spray reducing apparatus having a simple structure and low cost.

[0005]

To this end, the invention according to claim 1 is arranged in the stern along the ship side outer plate above the planned full load line at appropriate intervals in the ship length direction, and sprays compressed air respectively. It is characterized by comprising a plurality of air injection ports for injecting downward and an air compressor installed in the ship for supplying compressed air to the respective air injection ports through a plurality of pipes.

[0006] Next, the invention of claim 2 is a plurality of water intake ports arranged below the surface of the bow at the front end of the bow and above and below the planned full load water line and on the freeboard portion, and each of the above water absorptions is arranged in the ship. It is characterized by having a pump that inhales the spray from each of the mouths through a pipe, and then discharges it out of the ship through a discharge pipe.

Further, the invention according to claim 3 is such that the bow slope is slightly down to the vicinity of the shoulder along the ship side plate over the bow material and the ship side plate above the planned full load line at the ship freeboard. It is a horizontal waterway that extends in parallel with each other, and the lower tier sequentially extends longer toward the rear than the upper tier, and the rear end of the lowermost flume is located at the water surface. It is characterized in that it is equipped with a plurality of vertical pipes that are sequentially introduced into the region near the rear end of the lower waterway.

[0008]

According to this structure, the following actions are performed. (1) According to the invention of claim 1, the wave generated at the bow portion is limited in height that rises along the surface of the hull by the air jetted downward from the air jet port. Phenomenon and spray phenomenon are alleviated. (2) According to the invention of claim 2, since the pressure at the bow portion is lowered by absorbing the water from the plurality of bow water intake ports, the wave-making phenomenon is reduced, and the water rising along the surface of the hull is reduced. Since it is also sucked from the water suction port, it is less likely to reach the upper side and form a spray. (2) According to the invention of claim 3, the waves generated at the bow portion rise along the surface of the hull, and the spray that separates and falls is collected in the water channel and then guided backward and gently. It flows down to the surface. Therefore, interference with the bow wave can be avoided.

[0009]

1 is a side view of a bow portion showing a first embodiment of the present invention, and FIG. 1 is a schematic horizontal sectional view taken along the line I--I of FIG. II-
II is a lateral cross-sectional view, FIG. 3 is a view showing the residual resistance coefficient of this embodiment in comparison with the conventional one, and FIG. 4 is a side view showing the bow portion of the second embodiment of the present invention and its B- Cross-sectional view taken along arrow B, C
5 is a horizontal sectional view taken along the arrow C, FIG. 5 is a side view of the bow showing the third embodiment of the present invention, FIG. 6 is a lateral sectional view taken along the line VI-VI of FIG. 5, and FIG. 7 is taken along line VII-VII of FIG. FIG. 8 is a cross-sectional view taken along the arrow, and VIII in FIG.
-VIII lateral cross-sectional view, FIG. 9 is a horizontal cross-sectional view taken along the line IX-IX of FIG. 5, FIG. 10 is a horizontal cross-sectional view taken along the line XX of FIG. 5, and FIG. 11 is a horizontal cross-sectional view taken along the line XI-XI of FIG. FIG.

In the above drawing, the same reference numerals as those in FIGS. 12 to 13 respectively indicate the same or substantially equivalent constituent members to those in the same drawing. First, in the first embodiment shown in FIGS. Above the planned full load line LWL,
The air compressor 4 provided inside the hull 1 is connected by a pipe 5 and is provided along the surface of the hull at arbitrary intervals in the longitudinal direction. When the hull 1 configured as described above is traveling forward, waves are generated at the bow.

The generated wave tries to rise along the surfaces of the hull 1 and the bow material 2, but the upward force of the wave is weakened by injecting compressed air downward from the air injection nozzle 3. As a result, the wave resistance and the spray phenomenon are weakened, so that the increase in hull resistance is reduced.

FIG. 3 shows a comparison diagram of the residual resistance coefficient between the conventional one and the air injection device of the first embodiment of the present invention, in which the Froude number is a function of speed and the residual resistance coefficient is the friction from the total resistance coefficient. The resistance coefficient is subtracted. Therefore, the frictional resistance component due to the rise of the water head is included in the residual resistance coefficient. Since the wave-making phenomenon becomes more remarkable as the ship speed increases, it is more effective to control the capacity of the air compressor, the strength of the air pressure, etc. by a control unit (not shown).

As described above, according to the first embodiment, the air injection device arranged at the bow portion has the effect of reducing the wave-making phenomenon and the spraying phenomenon and reducing the hull resistance. It is effective for improving the propulsion performance of the ship.

Next, in the second embodiment shown in FIG.
3, 14, 15a, and 15b are the planned full load line L, respectively.
Upper and lower parts of the WL are water inlets provided on the bow 2 and its vicinity, and the water inlets 13, 14, 15a, 15b are connected to the pump 9 installed onboard via the pipes 6, 7, 8a, 8b, respectively. Has been done. The discharge port of the pump 9 is connected to a drain port 11 provided on the bottom of the ship via a pipe 10.

When the hull having such a structure is in motion, the pump 9 is operated and the water intake ports 13, 14, 15
By absorbing the water from a and 15b and discharging it from the drainage port 11, the pressure at the bow portion is reduced, and the wave-making phenomenon is reduced. Further, the water rising along the hull is also absorbed from the water intake ports 14, 15a, 15b provided on the freeboard, so the rising force is reduced, and the phenomenon of separation from the hull 1 to form a spray is reduced. To do. As a result, the surplus resistance of the hull resistance decreases in the same tendency as shown in FIG.
Further, in the second embodiment, four water intake ports are provided,
If necessary, it is more effective to add this to the freeboard above.

As described above, the wave-reducing device using the water inlet provided at the bow has the effect of reducing the resistance of the hull by reducing the wave-making phenomenon and reducing the spray phenomenon. It is an effective device for improving performance.

Further, in the third embodiment shown in FIGS. 5 to 11, reference numerals 23a, 23b and 23c are water channels symmetrically arranged along the port side shell plates including the bow, The water passages 23a, 23b, 23c are provided above the planned full-board draft boat LWL, projecting outward from the hull 1 and the bow member 2, and are provided on both sides at appropriate intervals in the depth direction. Here, each of the water channels 23a, 23b, and 23c is extended substantially parallel in the stern direction with a slight downward slope, and the upper water channel becomes shorter and becomes longer as the lower water channel becomes lower. The rear end of the lowermost water channel 23c is provided near the water surface at the shoulder of the bow.

When the hull 1 having such a structure is traveling forward, waves are generated at the bow. The generated waves rise along the surfaces of the hull 1 and the bow material 2, and most of them are separated and fall, so that the water that falls falls into the water channel 2.
It is received by 3a, 23b, and 23c, sent to the rear, and discharged near the water surface of the bow shoulder. Therefore, the interference with the bow wave is avoided, and the wave-making phenomenon caused by it is alleviated and the hull resistance decreases. The plurality of water channels 23a, 23b, and 23c are provided because the wave height generated by the change in the ship speed is different, so that the water channel 23 is used when traveling at the highest speed.
a, 23b, 23c, waterway 23 when traveling at medium speed
b and 23c, it is considered that sprays are collected in the water channel 23c when traveling at a low speed. According to such a third embodiment, the wave spray generated at the bow portion is received and discharged backward, thereby having an effect of avoiding interference with the bow wave and reducing the wave-making resistance. The same tendency as shown in FIG. 3 is effective for improving the propulsion performance of the ship by reducing the surplus resistance.

In short, according to the first aspect of the invention, the stern is arranged at appropriate intervals in the ship length direction along the ship side outer plate above the planned full load line, and compressed air is jetted downward toward the spray. It is equipped with multiple air injection ports and an air compressor installed in the ship that supplies compressed air to each of the above air injection ports through multiple pipes. The present invention is of great industrial benefit because it provides a cost effective ship bow reduction device.

According to the second aspect of the present invention, a plurality of water inlets are provided below the water surface and above the freeboard near the planned full load line at the front end of the bow, and at the freeboard portion. It is equipped with a pump that sucks the spray from each of the water inlets via the pipes and then discharges it via the discharge pipe to the outside of the ship. The present invention is of great industrial benefit because it provides a bow spray reduction device.

According to the third aspect of the present invention, a slight downward slope is symmetrically extended to the vicinity of the shoulder portion along the ship-side outer plate over the bow material and the ship-side outer plate above the planned full load draft at the freeboard of the bow. It is a horizontal waterway that extends in parallel with each other, and the lower tier sequentially extends longer toward the rear than the upper tier, and the rear end of the lowermost flume is located at the water surface. Equipped with multiple vertical pipes that are sequentially introduced near the rear end of the lower waterway, the falling spray is gently discharged after being collected in the waterway, which makes it an economical vessel with a simple structure and low cost. The present invention is of great industrial benefit because it provides a bow spray reduction device.

[0022]

【The invention's effect】 [Brief description of drawings]

FIG. 1 is a side view of a bow portion showing a first embodiment of the present invention and a sectional view taken along the line BB of FIG.

FIG. 2 is a cross-sectional view taken along the line II-II of FIG.

FIG. 3 is a diagram showing a residual resistance coefficient of the first embodiment in comparison with a conventional one.

FIG. 4 is a side view showing a bow portion of a second embodiment of the present invention, a lateral sectional view taken along the line BB and a horizontal sectional view taken along the line C-C.

FIG. 5 is a side view of a bow portion showing a third embodiment of the present invention.

6 is a transverse cross sectional view taken along the line VI-VI of FIG.

7 is a transverse cross sectional view taken along the line VII-VII of FIG.

8 is a transverse cross sectional view taken along the line VIII-VIII in FIG.

9 is a horizontal sectional view taken along the line IX-IX in FIG.

10 is a horizontal sectional view taken along the line XX of FIG.

11 is a horizontal sectional view taken along the line XI-XI of FIG.

FIG. 12 is a side view showing a bow portion of a conventional ship and its A;
-A is a horizontal sectional view.

13A and 13B show waves generated by the bow portion of FIG. 12, and FIG. 13A is a side view thereof and FIG. 13B is a front view thereof.

[Explanation of symbols]

 1 Hull 2 Bow Material 3 Air Injection Nozzle 4 Air Compressor 5 Pipe 9 Pump 10 Pipe 11 Drainage Port 13 Water Intake Port 14 Water Intake Port 15a, 15b Water Intake Port 23a, 23b, 23c Waterway LWL Plan Full Draft

Claims (3)

[Claims] 1. A plurality of air injection ports, which are arranged at appropriate intervals in the ship length direction along the ship side outer plate above the planned full load line at the stern, and inject compressed air downward toward the spray, respectively. A bow spray reducing device for a ship, comprising: an air compressor installed in a ship to supply compressed air to each of the air injection ports through a plurality of pipes. 2. A plurality of water inlets arranged at the front end of the bow in the vicinity of the planned full load line below the water surface and on the freeboard portion, and a plurality of water inlets arranged on the ship, each of which is provided with a spray through a pipe. A device for reducing the amount of spray on the bow of a ship, which comprises a pump that inhales and then discharges this through a discharge pipe to the outside of the ship. 3. A lateral line extending in parallel with a slight downward slope to the vicinity of the shoulder of the ship along the ship-side outer plate over the bow material and the ship-side outer plate above the planned full-load draft line on the freeboard side of the bow, respectively. It is a ditch-like canal, where the lower part of the canal extends longer toward the rear, and the rear end of the lowermost canal is located on the water surface, and the rear ends of the upper canals are closer to the rear end of the lower canal. A device for reducing the amount of spray on the bow of a ship, characterized by comprising a plurality of vertical pipes that are successively introduced to the parts of the ship.