JP3450851B1 - Ship sway reducing water tank and control method thereof - Google Patents

Abstract

Abstract: PROBLEM TO BE SOLVED: To release a gas generated when a fuel oil such as fuel oil A is used as a liquid to be used in a sealed rocking water tank to the atmosphere safely and automatically without troublesome labor. Eliminate the causes of gas fires (explosions). SOLUTION: An air vent pipe 17 having a closing device which is used only as a fuel tank and an anti-oscillating water tank and is opened only when fuel oil is supplied or transferred, and a closing device 13 such as a valve which enables remote driving are provided. A vent tube 12 is provided. The lower end of the degassing pipe 12 is connected near the top of the tank, and one end is connected to the atmosphere side from the position of the air vent closing device 8.
In the vent pipe, a cooling device 39 for cooling the gas is provided at an appropriate place. Then, based on the information detected by the sensor unit 21, a control signal from the control unit 25 is output to the degassing unit 28, and the gas filled in the tank is automatically released to the atmosphere with the temperature lower than the flash point. .

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an anti-sway water tank for reducing rolling of a ship, and particularly to a gas generated when fuel oil such as heavy oil A is used as a liquid for obtaining an anti-sway moment. BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a ship motion reduction tank that automatically releases to the atmosphere and a control method thereof.

[0002]

2. Description of the Related Art A U-tube type anti-sway water tank (hereinafter also referred to as ART) has been known as a conventional method for reducing rolling of a ship. When the liquid in the left and right wing tanks moves through the liquid duct due to the rolling motion of the ship, this ART causes a time lag, that is, a phase delay, with respect to the rolling cycle of the ship. The delay is used to reduce the rolling of the ship.

As shown in FIG. 3, the ART generally connects a pair of at least two wing tanks 2a and 2b set on both sides of the hull with the bottoms of these wing tanks to connect the liquid 37 to the left and right. A liquid duct 3 to be moved,
In the vicinity of the upper part of the relative position of both wing tanks, the air duct 5 communicating with the air duct closing device 6 such as a remotely driven valve for enabling the liquid to be braked and the cycle of the ART in the liquid duct. The variable damper 4 and the wing tank are further provided with air vent pipes through the jammer plates 9a and 9b for adjusting the liquid damping and the air vent pipe closing device 8 such as a valve which is required only when pouring and draining the liquid. The shaking water tank body 1 is configured.

By the way, when the air duct closing device is closed, the flow of air between the left and right wing tanks is cut off, liquid movement in the tanks is almost impossible, and the ART is deactivated. In this specification, this state is called non-operation.

When the ART is used, the above-mentioned non-operation is selected as necessary, but in order to obtain this non-operation, the inside of the tank needs to be hermetically sealed, and the liquid in the ART is A closing device 8 such as a valve is provided as an indispensable means in the air vent pipe 7 that is released only when pouring water.

Although not shown in FIG. 3, although necessary equipment such as a liquid water supply pipe, a liquid drainage pipe, a liquid level gauge for confirming the liquid level and a sounding pipe, etc., which are incidental equipment as a water tank, are provided, All the pipes that communicate with the outside, such as the water supply pipe, the liquid drainage pipe, and the sounding pipe for checking the liquid level height, are provided with a closing means to keep the inside of the ART airtight.

[0007]

During the operation of the ART, the liquid 37, which obtains the damping moment, reciprocates in the liquid duct 3 at a speed of about 3 to 5 m per second, reversing every half of the shaking. . As for the state of liquid, as shown in FIG. 5, the liquid 15 moving in the left and right direction of the ship is
Since the direction is changed to the vertical movement, at this time, the baffle plates 9a and 9b and an inner member (not shown) are agitated, and a considerable amount of droplets are generated to repeatedly move in and out of the air duct 5 together with the air 18. However, the commonly used liquids are fresh water and seawater, and the closed tank structure did not cause any problems. From these, ART has come to be adopted for various ship types because of its high anti-sway effect.

Particularly, since a pelagic fishing boat has a considerable distance to a fishing ground and requires a large amount of fuel oil, an AR which can also be used as a fuel tank as a means for securing as much fuel oil as possible
T was desired, and it was put into practical use in Japan in 1993, and since then, it has been installed in two to three vessels every year. From around 1999, it has been pointed out that there is a problem with the handling of air vent pipes when the ART and fuel tanks are combined, due to the regulations of the ship engine, which is a domestic law, or the operation of the ART.

Here, the application of the fuel tank and the air vent pipe of the ART and the difference in their construction will be briefly described. To explain from the conclusion, the air vent pipe in the case of the fuel tank is always opened without a closing device, while in the case of ART, the closing device is provided and always closed except when pouring and draining liquid. It is the opposite of that. First, the fuel tank will be described. The general fuel tank 29 shown in FIG. 4 stores the amount of oil required during voyage, and the width of the tank is 1/2 or less of the ship width even if it is large. There are many reasons for this, but it is necessary to reduce the influence of the free liquid level on the stability of the ship and to prevent the fuel oil from being discharged from the air vent pipe 30 by suppressing the synchronized fluctuation of the fuel 36 during shaking. To be From these, a plurality of fuel tanks are arranged to secure an optimum amount of oil according to the use and purpose of the ship, and the engine equipment and the individual fuel tanks are connected via a transfer means. Each fuel tank is operated through a fuel transfer pipe 33 required during refueling or transfer, and the air 34 in the tank flows out to the atmosphere during refueling through the air vent pipe 30 and to other tanks. At the time of transfer, it flows in from the atmosphere. As a matter of course, the gas 35 generated from the fuel oil 36 is always spontaneously discharged through the air vent pipe.

As an example of an air vent pipe for a fuel tank, it is assumed that the fuel oil in the fuel tank overflows from the air vent pipe due to overflow at the time of refueling or large shaking of the ship,
Atmosphere-side end of the air vent pipe is used as an overflow pan 3
The fuel oil overflowing up to 1 is returned to the fuel tank 29 through the return pipe 32 to the fuel tank, and the generated gas 35 is naturally released to the atmosphere. From these, it is stipulated in the regulations of the ship engine including the diameter of the fuel tank 29 that the air vent pipe 30 that is open to the atmosphere is provided without a closing device.

On the other hand, the ART, as shown in FIG. 3, constitutes an air vent pipe 7 capable of interrupting the flow of air through a closing device 8 such as a valve. As for the method of use, the tank is completely closed except when pouring or draining a predetermined amount of liquid 37 into the tank. The reason is that, as described above, it is necessary to keep the inside of the anti-sway water tank body 1 in a hermetically sealed state as a liquid braking means.

From these, when the fuel tank and the ART are used in common as shown in FIG. 5, they are used as follows. When leaving the port, the ART is filled with fuel oil and the air vent pipe closing device 8 serving as a fuel tank is opened. When used as an ART, ART
A predetermined amount of fuel inside is left, unnecessary parts are transferred to another fuel tank, and then the air vent pipe closing device 8 is closed,
The inside of the tank has a structure capable of maintaining a sealed state. However, a serious problem that did not occur when using fresh water or seawater as the liquid used, that is, a large amount of gas is generated from the fuel oil, and the internal pressure in the ART does not increase as the gas content increases. I received a point from the supervisory authority of the heel. Therefore, simply as a means of releasing this gas,
There was also an example of using the method in which the air vent pipe was opened like the fuel tank, but the following problems came to be pointed out by the occupants as the track record increased. (A) The ART cannot be deactivated when the air duct is open. (B) The free liquid surface is adversely affected by the ART liquid. (C) Fuel oil is discharged and causes marine pollution. (D) Noise is generated from the seawater inflow prevention valve provided in the air vent pipe. (E) The gas that is forcibly discharged by the movement of the liquid in the tank has a large gas content, and thus has a high risk of catching fire. In response to such a point at the site, the air vent pipe was closed and used as in the case of using fresh water or seawater. By the way, the ART in Japan was put into practical use for the first time in 1963, and there are about 300 vessels installed to date. Among them, the total number of 28 vessels equipped with an ART that doubles as a fuel tank was developed in 1993, and the total number is 28, but most of them are sailing with the above-mentioned problems.

On the other hand, the reason pointed out by the regulatory authorities is that the fuel used by ships is JIS standard (K2205).
-1991) is defined as Type A or Type 2 heavy oil with a flash point of 60 ° C or higher, and the gas content in the sealed container is from 1% to 6%. When the temperature of the gas reaches 60 ° C. or higher, it catches fire when there is a fire. For these reasons, the ship law of the domestic law requires the installation of an air vent pipe that is always open in the fuel tank, but this is not observed. In particular,
In the ART installed adjacent to the engine room, there is a concern that fuel oil or gas may leak from the valve part for the air duct or the damper part for changing the cycle, which may cause a fire accident. There is no means for releasing the gas having a large gas content generated in the ART, which is the cause.

In order to solve the above-mentioned problems, the present invention safely and automatically discharges the gas generated in a closed ART to the atmosphere or an overflow tank or the like, and a wobble reducing water tank for a ship. The purpose is to provide a control method.

[0015]

In order to achieve the above object, in the ART of the present invention, the gas generated in the tank is provided by providing a gas vent pipe through a gas vent device capable of automatic control. And release it.

As a discharging method, means for satisfying a part or all of the following is taken. (A) The gas temperature is cooled below the flash point (60 ° C.) and discharged. (B) Emit when the roll angle is relatively small. (C) A degassing pipe is installed through a closing device such as a valve that enables remote driving, and degassing is automatically controlled. (D) A blower or the like is provided near the discharge port to mix air and gas to reduce the gas content and discharge. (E) The temperature inside the tank or the gas to be discharged is grasped by a temperature controller or the like, and when the temperature is higher than a preset temperature, the degassing device is closed or controlled so as not to be released when the gas is being closed.

[0017]

BEST MODE FOR CARRYING OUT THE INVENTION It is an object of the present invention to provide a shaking motion reducing water tank for a ship and a control method thereof, which is characterized in that gas generated in an ART is safely and automatically discharged to the atmosphere. In order to grasp the roll angle and roll period of a ship and to control the natural period of the ART and control relating to liquid braking, the ART according to the present invention is also equipped with related devices and a control system. However, since it is not directly related to the present invention, a detailed description thereof will be omitted.
Hereinafter, embodiments of the present invention will be described based on examples with reference to the drawings.

FIG. 1 is an overall configuration diagram showing a main configuration showing an embodiment of an ART according to the present invention. As shown in FIG. 1, the basic structure of the ART for achieving the above-mentioned object is to connect a pair of at least two wing tanks 2a, 2b set on both sides of the hull and the bottoms of these wing tanks. A liquid duct 3 for moving the liquid (fuel oil) 15 in the left-right direction and a closing device 6 such as a remote-driven valve for enabling the liquid (fuel oil) to be braked near the upper portion of the relative position of both wing tanks. An air duct 5 and a damper 4 for changing the period in the liquid duct, which are communicated with each other via a means;
Inside the wing tank, the jammer plates 9a and 9b and the air vent pipe 7 with a closing device for releasing the fuel oil 15 in the ART only when refueling or transferring the fuel oil 15 are provided to constitute the anti-sway water tank body 1 that can also be used as a fuel tank. .

Although not shown, the necessary equipment such as a fuel oil supply pipe, a fuel oil transfer pipe, a liquid level gauge for confirming the liquid level and a sounding pipe, which are incidental equipment as a water tank, is provided. All pipes that communicate with the outside, such as the oil supply pipes, fuel oil transfer pipes, and sounding pipes for checking the liquid level height, are provided with a closing means to enable a sealed state.

Further, a gas vent pipe 12 is provided through a closing device 13 such as a valve which enables remote drive for venting gas inside the tank, the lower end of which is connected near the top of the tank and the other end is vented. Connection is made from the position of the closing device 8 such as a valve with the pipe 7 to the atmosphere side.

As shown in FIG. 6, the degassing device unit calculates and decodes the contents of the information output from the sensor unit 21 and the sensor unit 21 for detecting the information for discharging the gas inside the tank as needed, and Based on a control unit 25 that outputs a control signal and a control signal from the control unit,
It comprises a degassing device section 28 for remotely driving a closing device such as a valve with a degassing pipe, and a degassing pipe.

The sensor section 21 comprises a pressure sensor 17, a temperature controller for grasping the temperature in the tank or the temperature of the gas to be discharged and outputting a control signal, a gas concentration sensor 20 and the like, for detecting the gas generation state, and A shaking sensor 38 for detecting shaking of the ship is provided, and these pieces of information are output to the control unit.

The control section 25 comprises an operation decoding circuit 22, a control execution circuit 23, and an information processing circuit 24 for decoding the contents of information output from a part or all of the sensors of the sensor section 21.

The operation decoding circuit decodes the operation based on the data output from the sensor unit and monitors the presence or absence of gas generation according to the specifications input in advance. In addition, the swaying situation of the ship is always grasped from information such as inclinometers.

The control execution circuit outputs a control signal to the degassing device section for executing the opening / closing specification of the preset closing device such as a valve with a gas venting pipe based on the result decoded by the operation decoding circuit. Releases gas.

Further, the pressure in the tank due to the liquid is calculated based on the roll angle of the ship, and when the result decoded by the operation decoding circuit exceeds the preset pressure value, it is considered that a large amount of gas has been generated. There is also a control method of outputting a control signal for executing the opening / closing specification of a closing device such as a degassing valve and controlling the degassing device via a control execution circuit.

The gas concentration, the tank internal pressure, the tank internal temperature or the gas temperature, the motion information of the ship, and the operating status of each device are grasped by the information processing circuit one by one, and the information is stored in the IC memory. Although not shown,
It is also possible to display it on the control panel and send a signal to other navigation equipment as navigation information.

The degassing device section 28 includes a closing device 13 such as a drive source 26, a solenoid valve 27, and a valve 13 with a degassing pipe.
It consists of. Further, in the present embodiment, the gas venting device portion is installed on the port side, but it may be installed on both port sides, and the position and the number thereof are not restricted.

In the present embodiment, the drive system of the closing device such as the valve with the gas vent pipe is assumed to be hydraulically driven, but a pneumatic system or an electric system may be used, and depending on the system, the gas vent device may be used. Some parts that can be omitted may be omitted.

In this embodiment as a gas venting device, a valve with a gas venting pipe combined with a sensor portion was adopted, but an automatic breathing valve or a pressure reducing valve which detects the internal pressure and releases gas or the like may be used.

It is also possible to abolish a part or all of the sensor unit 21 which is the information source of the gas venting device and control the closing device such as a valve with a gas venting pipe by a timer. Although it is inferior in function to the degassing device including, this system may be adopted according to the specifications of the ship.

In addition, FIG. 2 shows that in the ART of FIG. 1, the lower end of the gas vent pipe 12 is connected to the air duct portion 5, and the gas 1
It is installed in the vicinity of the center of the hull as a means for suppressing the fuel oil 15 discharged together with the fuel tank 9 as much as possible. As described above, the lower end of the gas vent pipe may be connected to a position that is considered optimal from the space of the place where the gas vent pipe is installed, and is not positionally restricted.

Further, means for a cooling device (39) for obtaining a temperature lower than the flash point of the gas is provided at an appropriate position of the gas vent pipe. The simplest cooling method is to provide a cooling tank that uses seawater or miscellaneous water and pass a gas vent pipe into the tank. This is because the ship is equipped with a ballast tank (including a ballast pump) and a miscellaneous water tank (including a miscellaneous water pump), so that the cooling medium can be easily obtained. The liquid temperature in the ballast tank and miscellaneous water tank is about 40 ° C. at most, and the cooling device can achieve its purpose by using this as a refrigerant. It is also possible to install a full-scale cooling device, but it is not necessary to lower the gas temperature beyond the flash point more than necessary, and the point is to release the gas temperature below the flash point (60 ° C). Therefore, a relatively simple cooling device is sufficient. Therefore, it is not restricted to the type of cooling device or the cooling method.

By using the control method of driving the degassing device when the roll angle of the ship is relatively gentle, the possibility that fuel oil is discharged from the degassing pipe together with gas is extremely reduced.

The closing device equipped on the air vent pipe may be changed to a remote drive type so that it can also be used as the gas vent pipe. However, since the diameter of the air vent pipe itself is determined by the regulations of the ship engine, the equipment cost is expensive. However, it can be used as a means of the degassing device.

If the gas to be discharged is mixed with air by a blower or the like to reduce the gas content and discharge the gas, the risk of ignition is reduced, so these means may be incorporated.
Also, the temperature of the gas to be discharged is measured, and the preset temperature is
For example, when the temperature exceeds 55 ° C., the gas is instantaneously stopped while the gas is being discharged. Further, in the release preparation stage, if the degassing device is not released, further safety can be ensured.

[0037]

As is apparent from the above description, according to the present invention, even if the fuel oil is used as the ART liquid, it is possible to satisfy all the conditions as the fuel tank and the ART. Therefore, the following effects can be obtained.

(1) A large amount of gas generated when fuel oil is used can be safely and automatically released to the atmosphere. (2) Since the gas is released when the weather is calm, the discharge (outflow) of fuel oil in the ART can be suppressed, and the factors of marine pollution can be minimized. (3) Since the gas to be released has a temperature lower than the flash point by the cooling means, it is possible to prevent the ignition and the explosion from being triggered even if a fire species is present near the release point for some reason. (4) Since gas is released when necessary, the tank internal pressure becomes almost the same as the atmospheric pressure, and there is no problem of fuel oil or gas leakage due to the increase of tank internal pressure from the valve for the air duct or the lower duct part for changing the cycle. Be extremely reduced. The total number of Japanese vehicles equipped with an ART that doubles as a fuel tank is 28,
At present, the ship is sailing with the above problems, but according to the present invention, the condition as a fuel tank and the ART
It is an invention that can be expected to have an extremely high effect as a measure to prevent a gas fire (explosion), as it can safely and automatically perform degassing without human intervention. .

[Brief description of drawings]

FIG. 1 is an overall configuration diagram showing a main configuration showing an embodiment of an anti-sway water tank according to the present invention.

FIG. 2 shows an example of changing the position of the degassing pipe of the shaking water tank in FIG.

FIG. 3 is an overall configuration diagram showing a main configuration of a conventional general rocking water tank.

FIG. 4 shows a cross section of a prior art fuel tank and a system of air vent pipes.

FIG. 5 shows the movement of the liquid in the swaying water tank that doubles as a fuel tank and the wing tank of the prior art.

FIG. 6 is a block diagram showing an embodiment of a control mechanism configuration relationship of a control unit and a degassing device relating to control of the present invention.

FIG. 7 shows an example of cooling points of the gas vent pipe of the shaking water tank shown in FIG.

FIG. 8 shows an example of cooling points of the gas vent pipe of the shaking water tank in FIG.

[Explanation of symbols]

1 ... shaking water tank body 2a, 2
b ... Wing tank 3 ... Liquid duct (fluid moving duct) 4 ... Lower damper (for changing tank natural period) 5 ... Air duct 6 ...
Air duct closing device 7 ... Air vent pipe (air inlet / outlet pipe) 8 ...
Air vent pipe closing devices 9a, 9b ... Jammer plate 10 ... Overflow tray (tank) 11 ... Return pipe to fuel tank 12.
..Degassing pipe 13 ... Closing device for degassing pipe 14.
.. Liquid level 15 ... Liquid (fuel oil) 16 ... Overflowing fuel oil 17 ... Pressure sensor 18.
・ ・ Air 19 ・ ・ ・ Gas 20 ・
..Gas concentration sensor 21 ... Sensor part 22 ..
.... Operation decoding circuit 23 ... Control execution circuit 24 ...
..Information processing circuit 25 ... control unit 26 ..
..Drive source 27 ... Solenoid valve 28 ..
..Venting device 29 ... Fuel tank 30 ..
..Air vent pipe 31 ... Overflow tray 32 ... Return pipe to fuel tank 33.
..Fuel transfer piping 34 ... Air 35 ..
..Gas 36 ... Fuel oil 37 ..
..Liquid 38 ... shaking sensor 39 ..
··Cooling system

Claims (7)

(57) [Claims] 1. A pair of at least two set on both sides of the hull.
Two wing tanks (2a, 2b), a liquid duct (3) that connects the bottoms of these wing tanks to move the liquid (15) to the left and right, and a liquid braking device near the upper part of the relative position of both wing tanks. And an air duct (5) communicating with each other via a means of a remote drive type air duct closing device (6), a damper (4) for changing the cycle in the liquid duct, and a wing tank. Jama board (9
a, 9b), the air vent pipe (7) via the air vent pipe closing device (8), and a gas vent pipe closing device (1) that enables remote drive for the purpose of venting the gas (19) in the tank.
3) A gas vent pipe (12), a sensor section (21) for detecting the pressure or gas concentration inside the tank, and a control section for decoding the content of information output from the sensor section and outputting a control signal. Degassing device part (28) for remotely driving the degassing pipe closing device (13) based on control signals from the control part (25) and the control part.
In a sealed anti-vibration water tank equipped with, the control unit (25) decodes the information inside the tank output from the sensor unit (21) to execute a predetermined control specification, and a degassing device. An agitation reducing tank for a ship, characterized in that the section (28) is automatically controlled. 2. A pair of at least two set on both sides of the hull
Two wing tanks (2a, 2b), a liquid duct (3) that connects the bottoms of these wing tanks to move the liquid (15) in the left-right direction, and a liquid brake near the upper part of the relative position of both wing tanks. An air duct (5) communicating through means of a remote drive type air duct closing device (6), a damper (4) for changing the cycle in the liquid duct, and a wing tank. Jama board (9
a, 9b), the air vent pipe (7) via the air vent pipe closing device (8), and a gas vent pipe closing device (1) that enables remote drive for the purpose of venting the gas (19) in the tank.
3) A gas vent pipe (12), a sensor section (21) for detecting the pressure or gas concentration inside the tank, and a control section for decoding the content of information output from the sensor section and outputting a control signal. Degassing device part (28) for remotely driving the degassing pipe closing device (13) based on control signals from the control part (25) and the control part.
In a closed shaking water tank equipped with a cooling device (39) for obtaining a temperature lower than the flash point of the gas at an appropriate position of the gas vent pipe, information on the inside of the tank output from the sensor part (21) According to the result of decoding by the control unit (25), a predetermined control specification is executed,
An anti-sway water tank for a ship, characterized by automatically controlling a degassing device section (28). 3. A pair of at least two set on both sides of the hull.
Two wing tanks (2a, 2b), a liquid duct (3) that connects the bottoms of these wing tanks to move the liquid (15) in the left-right direction, and a liquid brake near the upper part of the relative position of both wing tanks. An air duct (5) communicating through means of a remote drive type air duct closing device (6), a damper (4) for changing the cycle in the liquid duct, and a wing tank. Jama board (9
a, 9b), the air vent pipe (7) via the air vent pipe closing device (8), and a gas vent pipe closing device (1) that enables remote drive for the purpose of venting the gas (19) in the tank.
3) A gas vent pipe (12), a control unit (25) having a timer function, and a remote control of the gas vent pipe closing device (13) based on a control signal from the control unit. A sealed anti-sway water tank provided with a degassing device section (28) for automatically controlling the degassing apparatus section according to a preset time. 4. A pair of at least two set on both sides of the hull.
Two wing tanks (2a, 2b), a liquid duct (3) that connects the bottoms of these wing tanks to move the liquid (15) in the left-right direction, and a liquid brake near the upper part of the relative position of both wing tanks. An air duct (5) communicating through means of a remote drive type air duct closing device (6), a damper (4) for changing the cycle in the liquid duct, and a wing tank. Jama board (9
a, 9b), the air vent pipe (7) via the air vent pipe closing device (8), and a gas vent pipe closing device (1) that enables remote drive for the purpose of venting the gas (19) in the tank.
3) A gas vent pipe (12), a control unit (25) having a timer function, and a remote control of the gas vent pipe closing device (13) based on a control signal from the control unit. In a sealed anti-vibration water tank equipped with a degassing device section (28) for allowing and a cooling device (39) for obtaining a temperature lower than the flash point of the gas at an appropriate position of the degassing pipe, depending on a preset time. , A vessel shake reduction water tank characterized by automatically controlling a degassing device section. 5. The control unit decodes the contents of information output from a part or all of the sensor,
The control device according to claim 1, 2, 3 or 4, wherein a predetermined control specification is executed to automatically control the degassing device section.
Alternatively, the method for controlling the water movement reducing water tank of the ship according to claim 4. 6. The degassing device section (28) is driven to release gas when the average roll angle of the ship is smaller than a preset value. The method of controlling the water movement reducing water tank according to claim 5. 7. A temperature controller for measuring the temperature in the tank or the temperature of the released gas and outputting a control signal based on the information, and degassing when the temperature is higher than a preset temperature value. 3. The device part (28) is closed or is not actuated for release.
The method for controlling a water tank for reducing vibration of a ship according to claim 3, 4, 5, or 6.