Oscillation reduction water tank device for giant container ship and the control method therefor

Abstract

To provide an oscillation reduction water tank device and a control method that can withstand a parametric rolling, related to a rolling reduction for a giant container ship.SOLUTION: An A.R.T. body has a mountain shape in a cross section shape that a new concept center tank and left and right liquid passages are connected to a STABILO-made, DW-type A.R.T. based on a U-shaped tube type. Based on the average rolling period of the ship, left and right virtual tank functions are created bordering on the longitudinal bulkhead 5 below an equipment room. An oscillation reduction water tank device comprises a program to control automatically the virtual tank and the function of the A.R.T. body, and a program to predict whether or not the parametric rolling phenomenon occurs. It is possible to provide an A.R.T. equipment that can keep the liquid weight used within about 1,000 tons and can obtain an effective attenuation factor even for a giant container ship with a displacement volume of 200,000 tons class.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a motion reduction tank device and a control method for parametric roll motion, which are related to the roll motion reduction of ever-increasingly large ships, particularly large container ships. [Background technology]

[0002] In accordance with the Ship Safety Act and Ship Stability Regulations, Japan has been promoting the use of motion reduction devices that reduce the roll angle of ships in rough weather to 20 degrees or less. In particular, car ferries that carry "flammable cars and a large number of passengers" equipped with highly flammable fuel have been specified, and two types of "Fin Stabilizers" and "Anti-rolling Tanks (hereinafter referred to as ART)" have been designated as effective motion reduction devices for ships, and their installation has been mandatory since 1973, making them legal equipment.

[0003] There are two types of ART: active and passive. The passive type includes the "Flume type" with a rectangular cross section and the "Frahm type" with a U-tube shape (hereinafter simply referred to as the U-tube type or ART), and this application employs the "Frahm type." This technology utilizes the natural phenomenon of liquid flowing from higher to lower places, and was invented by Frahm in 1910 to create a system in which the liquid is "one beat delayed" in response to the rolling of the ship. This device consists of symmetrical vertical tubes (wing tanks) on both sides of the ship's hull, and a liquid passage (also called a lower duct) that connects the bottoms of these vertical tubes and moves the liquid w in the tanks left and right. The speed at which the liquid moves (also called the natural period of the tank or water tank) can be calculated from the ratio of the longitudinal cross-sectional area of ​​the wing tank and the liquid passage, and it is known that by designing the tank's natural period (Tts) to be approximately equal to the ship's rolling period (STs), a phase lag of 90 degrees occurs between the waves that induce the ship's rolling, the ship's rolling, and the liquid in the tank, resulting in a high rolling reduction effect (see Figure 2). In Japan, an article entitled "On the Design of Anti-Roll Tanks", which included the Frahm formula, was published in the Shipbuilding Council Bulletin No. 46 in 1930, and the MN formula, which was put into practical use in 1963 through a joint effort between industry, government and academia, is well known.

[0004] However, this U-shaped pipe type wing tank, including the MN type, is a single tank (single type) whose tank natural period cannot be changed and is unsuitable for merchant ships whose live load changes greatly, so the present inventor has put into practical use an optimum shape and control method suitable for the type, size and use of a ship by dividing the single tank with a longitudinal bulkhead in the bow-stern direction and using a "Double Wing (DW type)" with different tank natural periods, and a "Triple Wing (TW type)" equipped with three wing tanks. The DW type ART is a device approved by the former Ministry of Transport as the "D·W anti-rolling tank manufactured by Stabilo Corporation" and is described in the following non-patent document 1. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Patent No. 3537785 (Ship motion reduction tank device and its control method) [Patent Document 2] Patent No. 3377782 (Ship motion reduction tank device and its control method) [Patent Document 3] Patent No. 30428865 (Control method for vessel motion reduction tank device) [Patent Document 4] No. 2144338 (Ship rocking tank device) [Patent Document 5] Patent No. 4262127 (Parametric Roll Prevention Device) [Patent Document 6] Patent No. 4721169 (Variable period anti-rolling tank device for preventing parametric roll) [Non-patent literature]

[0006] [Non-Patent Document 1] Notice No. 115-2 of the Marine Inspection (dated November 18, 1987, Chief Ship Inspector of the Maritime Technical and Safety Bureau) [Non-Patent Document 2] TopTier N2M Paramatric Roll Following Seas V1.1Notice to Mariners Beware of parametric roll in following seas [Non-Patent Document 3] Performance Estimation of Anti-Rolling Tank as a Parametric Roll Prevention Device (Second Report) Journal of the Japan Society of Naval Architects and Ocean Engineers No. 8 December 2008 Summary of the Invention [Problem to be solved by the invention]

[0007] The present invention relates to an ART for huge container ships, unprecedented in size, with a ship width of 40 to 60 m, GM of 2.0 m or more, and a displacement of 150,000 to 300,000 tonnes, and to the prevention of parametric rolling.

[0008] (1) Since around 2000, as container ships on international routes have become larger, the number of containers they can carry has increased dramatically, resulting in numerous accidents in which a large number of containers have been lost or damaged during voyage. One of the causes of these accidents is believed to be the occurrence of a large roll angle known as parametric roll. One response to this issue is the patent documents 6 and 7, which were filed in 2004 for an "Anti-rolling water tank device for preventing parametric roll." (2) In the winter of 2020-2021, there were many serious accidents involving container losses. In response to this, a joint industry project (The TopTier project) was launched to find measures to prevent the recurrence of similar accidents. It became clear that parametric rolling in following seas is particularly dangerous, and advice was provided to container ship crew and staff involved in operations on how to plan, recognize, and take action to prevent parametric rolling in following seas (Non-Patent Document 2).

[0009] In 2021, we received many requests for ART equipment for large container ships, and one of the conditions presented was, (1) The ship's length is 335.0 m, width is 50.0 m, depth is 30.0 m, displacement is 200,000 tons, and the stability performance from full load to entering port is GoM value 4.0 to 2.0 m, roll period is 20 to 30 seconds, and target roll reduction efficiency is 50%. (a) The ART plan must first provide ART dimensions that can satisfy the required anti-rolling efficiency based on the stability parameters and the vertical installation position of the tanks specified in the order specifications. (b) Therefore, when the ship width of 50m, GoM value of 4.0m, and rolling period of 20 seconds presented by the client are applied to the conventional calculation, the average liquid flow velocity is about 5.0m / s. In addition, when the GoM value is 2.0m and the rolling period is 30 seconds, the average liquid flow velocity is about 3.33m / s. (c) The roll period assumed in desk calculations is 20 to 30 seconds. Taking into account head waves (also called forward waves) and following waves (also called forward waves), the effective roll reduction period range becomes 18.5 to 34 seconds. (d) To obtain the requested roll reduction efficiency of 50%, the stability coefficient stated in paragraph 0023 (1) stability specifications of this application is 800,000 tm. Considering these large values, the required tank length is about 15 m, liquid passage height is about 2.5 m, weight of liquid used is about 2,200 tonnes, and it is about 1.1% of the displacement. Incidentally, in Non-Patent Document 3, Performance Estimation of Anti-Rolling Tank as a Parametric Roll Prevention Device (Second Report), the displacement is 105,000 tonnes and the stability coefficient is 111,300 tm. (See Table 1) (2) The load of 2,200 tonnes of liquid would reduce the amount of cargo that could be carried, and the cost-effectiveness of ART equipment is far from being practical. There is currently a strong demand for new developments.

[0010] Overview of prior art relating to anti-rolling tank devices for preventing parametric roll and comparison with the present application. (1) Results of prior art searches, etc. (a) Search type: Patent search using J-Platpat (b) F1 / IPC: B63B39 / 03 (c) Search scope: Search formula for "full text scope" (d) Search items: F1(B63B39 / 03): 268 results and IPC(B63B39 / 03): 381 results. (e) Search item: F1 / IPC+keyword (e1): There were 0 entries for "huge ship + huge container ship + mountain shape" in both F1 and IPC. (e2): “Reduced shaking tank (74 cases / 91 cases), ART (21 cases / 22 cases). (e3): "Anti-rolling tank (15 / 17 cases), "U-shaped pipe type (41 / 44 cases)" (e4) "Parametric roll + anti-rolling tank device": FI: 2 / IPC: 2. (2) Regarding the contents of the prior art search, (a) A prior art check was conducted on motion reduction tank equipment for large container ships, but no disclosure of the "cross-sectional shape being mountain-shaped," which is a characteristic of the present invention, was found, and therefore the invention is considered to be novel. (b) Parametric roll + anti-rolling tank equipment is disclosed in “Patent Document 5 and Patent Document 6.” Both of these documents are by the same inventor and use a “U-tube type (single type).” A comparison with the present invention is shown below. (3) In the parametric roll prevention device of Patent Document 5, the paragraph "Summary and Solution" describes one of the solutions as follows: "By adding or removing liquid (seawater) from tank 5 installed in hull 1, the position of the center of gravity of hull 1 is shifted, and the roll period of hull 1 is changed, so that the ratio of roll period to pitch period deviates from a certain pre-set condition for occurrence of parametric roll." However, it is technically impossible to change the roll period value by adding or removing liquid weight of about 0.6% of the displacement, and the present invention does not provide any means for eliminating the roll reduction effect by removing the liquid. (4) In Patent Document 6, (a) Paragraph 0014 of the same document clearly states that "the weight of the liquid carried in the anti-rolling tank is 0.8% to 0.2% of the displacement of the vessel..." but does not disclose or suggest any specific numerical values ​​for the "weight of the liquid used" and the "displacement." (b) Paragraph 0015 of the same document specifies the configuration of a U-shaped tube, stating that the anti-rolling tank includes "an anti-rolling tank having a pair of wing tanks and a connecting channel connecting the lower parts of the pair of wing tanks, a damper provided in the connecting channel for adjusting the oscillation period of the liquid in the anti-rolling tank by opening and closing the damper, an air duct connecting the upper parts of the pair of wing tanks, and a valve provided in the air duct for switching the operation or stopping of the liquid in the anti-rolling tank by opening and closing the air duct." However, in the case of a U-shaped tube, "a pair of wing tanks," "connecting connecting channel," "damper for adjusting the oscillation period of the liquid in the liquid passage," "air duct connecting the upper parts, and its valve" are essential publicly known technologies, and there is no specific disclosure or suggestion of any specifications or control methods. (c) Paragraph 0016 of the same document states that "the air duct is... thus characterized in that the air duct is provided on the stern or bow side of the anti-rolling tank." However, this technology is not used in the present invention, and when it is not possible to install it at the top, it is possible to use the solution described in Patent Document 4. (d) Paragraph 0020 of the document states that "The amount of moment required to prevent parametric rolling has not been elucidated or known until now, and therefore a design method for a variable-period anti-rolling tank device for preventing parametric rolling has not been established..." However, it is impossible for the ART, which does not have the necessary anti-rolling moment, to "prevent parametric rolling." (e) Furthermore, the required ART anti-rolling moment can be easily determined from the ship's "displacement," "KG," "GoM," "ship's rolling period," "target anti-rolling efficiency," etc. (f) As can be seen from the above comparison, the prior art documents (Patent Documents 5 and 6) and the present invention are significantly different in terms of the shape of the ART, the configuration and specifications of the ancillary equipment, and the control means. (5) Incidentally, “Non-Patent Document 3” is a paper on the results of experiments on ART, an anti-parametric rolling technique used to prevent the parametric rolling of huge container ships, conducted around 2008. It contains the following information and is a valuable resource: (a) A comparison of the examples of the present application with the main items of the prior art is shown in Table 1 below. (b) The tank types in Patent Documents 5 and 6 and the non-patent document in Table 1 below are U-shaped tube type (Single Wing Type). TIFF2025007280000002.tif41149 [Means for solving the problem]

[0011] The present invention, which solves the problems related to the excessive liquid weight used in the ART and parametric rolling, will be explained in an easy-to-understand manner by dividing it into the sections "ART" and "Parametric Rolling". (1) The detailed technical description of ART is set out in paragraphs 0012 to 0035. (2) An explanation of parametric roll is provided in paragraphs 0036 to 0039.

[0012] The basic technology related to the ART for huge container ships described in paragraph 0007 that the present invention aims to solve is the achievements of Patent Documents 1 to 4 (technologies by the present inventors) and their improvements. In addition, to deal with parametric rolling, a calculation program that predicts whether or not parametric rolling will occur is added to the program that executes the ART function, and a controllable technology is provided to prevent parametric rolling. (1) Patent Document 1 is for large merchant ships, and has been well received for its various values, such as ship length: 158.0 m, ship width: 30.2 m, GM value: 2.0 m, displacement: 16,000 tonnes, tank length: 3.6 to 4.8 m, roll period: 11 to 26 seconds, liquid passage height: 1.5 m, and the weight of liquid used in the ART tank is approximately 200 to 260 tonnes. (a) The comprehensive technology required for the design of ART is described in paragraph 0003, which is the calculation of the ship's natural period, through to the control group in paragraph 0044, and the improvement thereon constitutes the technology of the present invention. Incidentally, much of this disclosure is reused in paragraphs 0013 to 0035 of the present invention. (b) Patent Document 2 describes a technique for determining whether or not a ship will be in a following wave state based on external information such as wind direction, wind speed, ship speed, period, etc. This technique is improved to construct a program related to parametric rolling. (c) Patent Document 3 describes techniques such as moving average periodic calculation and multiple control groups. By improving this technology, the composition described in Table 2 of paragraph 0035 of the present invention, which also corresponds to parametric rolling, has been developed. The results can be obtained. (d) Patent Document 4 describes a measure to be taken when it is impossible to install the air communication pipe at the top. (2) As mentioned above, the above-mentioned prior art documents (Patent Documents 1 to 4) are known to the inventors of the present application, and although the inventors are familiar with the technical contents thereof, the drawings and the like thereof have been omitted in the present application.

[0013] (1) The ship’s width is 40 to 60 meters, which is incomparable to the large ships that have been equipped with ARTs with a width of approximately 30.0 meters. The large stability coefficient arises from this width. Specifically, when the GoM value is 4.0 meters and the ship’s rolling period is 20 seconds, the weight of the liquid used is calculated backwards from the average flow velocity of the liquid moving in the ART, which corresponds to a GoM value of 4.0 meters and a rolling period of 20 seconds. This amounts to 2,000 to 3,000 tonnes of liquid. (2) Therefore, in the case of the U-shaped tube type ART, the narrower the overall width of the tank is, the smaller the cross-sectional area of ​​the liquid passage can be made. As a design means to reduce the weight of liquid used as much as possible, we invented the design technology of the DW type ART and the shape of Figure 1, which is an ART that reflects that concept and has a mountain-shaped cross section (hereinafter referred to as mountain-shaped). (3) In the angle-shaped ART, the means for slowing down the average flow velocity of the moving liquid consist of a center tank 3 which narrows the tank width, an independent equipment room 4 within the center tank, a vertical bulkhead 5 located in the center of the hull below the equipment room, one pair of liquid passages 6p, 6s on each side, and DW-type wing tanks 2p, 2s. (a) The two imaginary tanks 1p and 1s, separated by the longitudinal bulkhead 5, are as follows (b) and (c). (b) Virtual tank 1p refers to the port side tank bounded by the port wing tank 2p, the liquid passage 6p, and the longitudinal bulkhead below the equipment room. (c) The hypothetical tank 1s refers to the starboard tank including the center tank on the starboard side, the liquid passage 6s, and the starboard wing tank 2s, bounded by the longitudinal bulkhead below the equipment room. (4) Figure 3 shows the state in which the above items (a) and (b) are connected, which enables the structure and function of the angle-shaped structure to be realized.

[0014] Claim 1 of the present invention relates to a motion reduction tank device for huge container ships, which relates to the ART body having a mountain-shaped cross section, consisting of a center tank that can form a pair of virtual tanks 1p, 1s, each with a width approximately half that of the ART's width, and which is effective in reducing rolling during rough weather as well as parametric rolling, and which makes it possible to predict and avoid parametric rolling.

[0015] The invention of claim 2 relates to a center tank 3 essential for creating the virtual tanks 1p and 1s, and an equipment room 4 provided within the center tank, and is characterized in that the motion reduction tank device for a huge container ship described in claim 1 is equipped with these.

[0016] The invention of claim 3 relates to the liquid passages 6p, 6s of the ART, and is characterized in that it comprises a hardware means for obtaining a plurality of different tank natural periods.

[0017] The invention of claim 4 is as follows: (1) A means for constructing a control group (CASE1-9) including multiple different tank natural periods; (2) A preset average roll period value (also simply called the roll period) for control is set as a threshold value (25.5 seconds), and when a value below this threshold is detected, it is made to correspond to the effective roll reduction period range of 18.5 to 26 seconds. This creates the functions of center tank 3 and virtual tank. (3) When the roll period exceeds the threshold, the center is adjusted to correspond to the effective roll reduction period range of 25.5 to 34 seconds. -Tank 3 and Virtual Tank functions unlocked, (4) ART is deactivated when a preset period of 34.5 seconds or more is detected. (5) A method for controlling a motion-reducing tank system for a huge container ship according to claim 1, characterized in that the method controls the drive of the equipment essential to the above items (1) to (4).

[0018] The invention of claim 5 relates to a method for dealing with parametric rolling, and is a control method for a motion-reducing tank device for a huge container ship as described in claim 1, characterized in that a calculation program for predicting whether or not parametric rolling will occur is added to the program of claim 4 which executes the ART function, thereby instantly dealing with the rolling conditions of the ship that is encountered. Effect of the Invention

[0019] The above-mentioned invention of the present application reflects the technology cultivated for large ships, even in huge ships that are difficult to put into practical use for commercial ships and have never been equipped with ART before. The mountain-shaped ART makes it possible to reduce rolling during rough weather, which is common for huge container ships on international routes, to predict whether or not the phenomenon of parametric rolling will occur, to avoid it in advance, and to instantly take measures to reduce rolling if a parametric rolling state does occur. In particular, the equipment used can be of the same specifications as that used for conventional large ships, making this an invention that is highly effective as a rolling reduction tank device for huge container ships. [Brief description of the drawings]

[0020] [Figure 1] FIG. 1 is a perspective view of a mountain-shaped anti-rolling tank body 1 according to the present invention. When viewed from the stern (rear) of the ship, the left side of the figure is called the port side, and the right side is called the starboard side. [Diagram 2] This is a table showing the phase lag between the waves (Mt), the ship (FMt), and the anti-rolling moment of the tank (TMt). [Diagram 3] This is a cross-sectional view showing an example in which the functions of wing tanks 2p, 2s and virtual tanks 1p, 1s are created by closing a gate 5c that opens and closes an opening 5o in a longitudinal bulkhead 5 and opening a valve 7v with air ducts 7a, 7b. [Figure 4]FIG. 4 is a cross-sectional view of an example showing the liquid movement state when the vessel makes a half rotation in FIG. 3. [Diagram 5] FIG. 3 is a cross-sectional view of an example in which the gate 5c is opened to release the center tank function, the left and right liquid passages 6p, 6s, and the virtual tanks 1p, 1s, and the valve 7v with the air duct 7b is closed 7vc, thereby using the outer wing tank 2ot. [Figure 6] FIG. 6 is a cross-sectional view of an example showing the state of liquid movement when the vessel makes a half turn in FIG. 5. [Figure 7] FIG. 13 is a perspective view showing an example of a center tank and an equipment room shape and an arrangement of the equipment above a liquid passage. [Figure 8] FIG. 8 is a plan view showing an example of a liquid passage top plate near the center tank in FIG. 7. [Figure 9] FIG. 8 is a vertical cross-sectional view taken along the center line of the center tank in FIG. BEST MODE FOR CARRYING OUT THEINVENTION

[0021] The specification of the present invention is intended to be filed as an international PCT application with a view to expanding overseas, and therefore includes some overlapping explanations based on the ideas of the present inventors, including publicly known technologies. (1) The most important thing when planning ART is to understand the ship's natural roll period. The formula for estimating the natural rolling period based on Japan's ship stability regulations is as follows: Ts (ship's natural rolling period) = (2.01 x B xk) / √GoM (unit: seconds) B: ship width (m), k: radius of gyration (coefficient), GoM: metacentric height (m) From this formula, we can understand that the larger the GoM value in the denominator, the shorter (faster) the roll natural period. Incidentally, if the displacement is constant, the larger the GoM value, the larger the required anti-rolling moment. (2) The ship's rolling period STs is the same as the ship's natural rolling period FTs when it encounters regular wave periods, but when it encounters irregular wave conditions, the ship's rolling period differs depending on the angle and period of the encounter between the wave and the ship, and large rolling is induced especially when the encounter period with the ship and the ship's natural period Ts are synchronized. Note that we will not go into the details of wave height here. (3) The natural period of a tank, Tts, is the time it takes for the liquid in the tank to make one round trip. In the case of a passive tank, the liquid in the tank moves after the ship is induced by an external force. (4) Explain the phase lag between the waves that induce ship rocking, rolling, and liquid movement in the tank. (a) The swaying of a ship is induced with a delay of one step when the wave period and the ship's natural roll period are the same. This one-step delay is called the phase lag between the waves and the ship. (b) When the ship's rolling period and the tank's natural period become almost the same, the liquid movement occurs one beat behind the ship's rolling. This state of the ship and the liquid movement is also called phase lag. (c) To achieve a high roll reduction effect, it is essential that the roll period matches the tank's natural period. (d) The rolling of a ship is a repetitive motion, and if one rolling is considered as one rotation (360 degrees), it can be expressed as horizontal (0 degrees) ⇒ starboard incline (1 / 4 rotation: 90 degrees) ⇒ horizontal (1 / 2 rotation: 180 degrees) ⇒ port incline (3 / 4 rotation: 270 degrees) ⇒ horizontal (one rotation: 360 degrees = 0 degrees). The composition of the phase lag is shown in Figure 2, and although theoretically it is a smooth sine curve, in this figure it is shown as a straight line to emphasize the phase lag of the waves, the rolling of the ship, and the liquid in the tank, and each interval between each vertex is one rolling motion, which is one cycle. (e) In ART, the flow is: waves induce the ship ⇒ ship rolls ⇒ liquid movement in the tank. There is always a 90 degree phase lag between the waves and the ship roll. Furthermore, when the roll period value STs and the tank natural period value Tts are the same, there is a 90 degree phase lag between the ship roll and the liquid movement in the tank. In other words, if the peak of the wave force Mt that induces the ship is on the starboard side, the peak of the tank's anti-rolling force (also called anti-rolling moment) TMt, which has a phase lag of 180 degrees, is on the opposite port side. This means that the wave force Mt that tries to roll the ship and the anti-rolling force TMt that tries to suppress the ship's roll are in opposite directions, and therefore the two forces cancel each other out, resulting in an anti-rolling effect.

[0022] First, a basic explanation of the rolling state will be given. (1) Regarding shaking conditions during stormy weather: (a) The motion of a ship at sea is a well-known phenomenon that occurs when the period during which the ship encounters waves coincides with the ship's natural rolling period. (b) The rolling state of a ship is determined by its course and the direction of the waves. The bow in the direction of the ship’s movement is defined as (0°), the port side is (90°), the stern is (180°), the starboard side is (270°), and the bow has turned around once (360°=0°). (c) The maximum pitch angle occurs when there are head waves from the bow (0°) and following waves from the stern (180°). (d) The maximum roll angle occurs when the beam waves are coming straight from the side (90° and 270°). (e) The boundaries between vertical and horizontal sway are 45°, 135°, 225°, and 315°. (f) The ranges of pitch sway are between 0° and ±45° and between 135° and 225°. (g) The ranges of lateral sway are between 45° and 135° and between 225° and 315°. (2) Explain the roll period, which is essential for ART control, and the means for analyzing angle information. (a) For passive ART control, it is not necessary to use a different vibration value for each vibration. For example, it is sufficient to average multiple accumulated data during measurement. For example, five pieces of data can be analyzed as follows: A simple moving average will suffice: add the next 6th value to the 5 data points, drop the oldest value first, and divide the sum by 5. A1=(n1+n2+n3+n4+n5) / 5 ⇒ A2=(n2+n3+n4+n5+n6) / 5. (b) Moving average rolling period (ATs) = (STs1 + STs2 + STs3 + STs4 + STs5) / 5 STs: Ship rolling period (c) Moving average pitch period (APs) = (SPs1 + SPs2 + SPs3 + SPs4 + SPs5) / 5 SPs: Ship pitch period (d) Moving average roll angle (ATθ) = (STθ1 + STθ2 + STθ3 + STθ4 + STθ5) / 5 STθ: Ship's rolling angle (e) Moving average pitch angle (APθ) = (SPθ1 + SPθ2 + SPθ3 + SPθ4 + SPθ5) / 5 SPθ: Ship pitch angle (3) Roll information used for ART control (a) The inventors of the present application have adopted the moving average calculation method based on over 50 years of experience and experience in the field of ART. (b) Based on past experience, the optimal number of accumulated data points to use in calculating the moving average is 3 to 5, but there is no need to be so limited. (c) Furthermore, if the amount of data is small, the number of times the device is switched and driven increases, and conversely, if the amount of data that changes from moment to moment increases, the accuracy of instantaneous prediction decreases.

[0023] Hereinafter, an embodiment of the ART of the present invention will be described with reference to the drawings. It should be noted that Figs. 1 to 9 are merely explanatory of the form, and the scale of the drawings is ignored. In addition, the examples may be implemented to suit different configurations for each ship depending on the order conditions of the client (shipyard, design company, shipowner), and are not limited to the specific examples described in the embodiments shown below. (1) Ship stability parameters (a) Stability is the force that attempts to return a ship to its original position when it has tilted due to some factor. In this embodiment, the stability coefficient is displacement (200,000t) x GoM (4.0m) = 800,000tm. (b) The ship's breadth and tank width shall be 50.00m. (c) Hypothetical tanks 1p and 1s are symmetrical and have the same dimensions, with the width of each tank being 25.00 m. (d) The tank length is 9.00m based on the calculation results based on the stability specifications presented by the client, but the length is divided into two equal parts, 4.50m x 2 sets, and one of them will be explained. If the tank is made longer, it will be affected by the steady vertical inclination and pitching of the hull, and the liquid in the tank will also move in the bow and stern directions, so it is desirable to divide the tank length and shorten it in order not to interfere with the left and right liquid movement required for reducing roll. (e) The ART bottom plating will be located 33.0 m above the ship's bottom plating, with its fore-aft position near the center of the hull, and a bridge including a living deck will be installed above the ART. The purpose of this is to improve visibility by raising the bridge position in container ships, which are stacked high with containers, and to eliminate the need to secure new space for the ART installation, and therefore to eliminate the need to consider a reduction in the number of containers. (f) In ships that have living decks or bridges at two locations, one fore and one aft, it may be possible to have them in two locations if necessary due to the length of the ART, but this is not a requirement of the designer. (g) It is desirable to avoid the fore-aft location of the ART near the bow and stern whenever possible. The reason for this is that the larger the ship, the greater the weight and liquid weight required for the ART, which will have a negative effect on the ship's trim and longitudinal strength. EXAMPLES

[0024] Hereinafter, an embodiment of the present invention will be described in detail with reference to the drawings. However, the present invention can be embodied in many different forms for each ship depending on the type, size, stability values, and installation location of the ART of the ship, and is not limited to the specific examples described in the embodiments shown below. The basic overall structure of ART to achieve the above-mentioned objectives is as follows: (1) As shown in Figure 1, the ART main body 1 has a center tank 3 between DW type wing tanks 2p and 2s of the same dimensions on both sides of the hull, which are based on a U-shaped tube type, and the tank 3 and the wing tanks 2it have a pair of liquid passages 6p, 6s on the left and right sides at the bottom, which move liquid w to the left and right. The tank is sealed and has a mountain-shaped cross section. (a) The effective roll period range of the ART for roll reduction is set at 18.5 to 34 seconds, taking into account head waves and following waves, and the roll-response threshold for controlling whether or not to use the virtual tank is set at 25.5 seconds. (b) When the average roll period ATs is short and below the threshold, the virtual tank functions to be able to handle head sea conditions. (c) When the average rolling period is long and exceeds the threshold, the virtual tank function is deactivated and the ship is able to withstand following seas. This enables the ART main unit to function in a variety of ways.

[0025] The DW type wing tanks 2p and 2s each have a longitudinal bulkhead 2bh running from bow to stern within the tank, and consist of tanks 2it and 2ot which divide the wing tank into left and right halves by the longitudinal bulkhead. (1) The longitudinal bulkhead is located an appropriate distance from the top plate of the inner outer plate 2b that constitutes the tanks 2p and 2s, and using that position as a base point, a downwardly sloping plate inside the wing tank is connected to the longitudinal bulkhead 2bh. (a) The purpose is to increase the volume of the upper part of tank 2ot and to prevent the moving liquid w from colliding with the top plate of the wing tank during strong shaking. (b) The lower end position of the vertical bulkhead shall be at the same height as the inside dimension of the top plate height of the liquid passages 6p, 6s. (2) The height of the wing tank shall be 10.00 m. (a) Assuming that the tank width of the ART body is 50.00m and the roll angle is 15°, the upward movement height of the liquid in the wing tank is about 6.7m, and adding the water level in the tank body (here 1.80m) to this value gives 8.50m. Taking into account factors such as acceleration, it is desirable to make it even higher. (b) In particular, in order to obtain the roll reduction effect during parametric roll, which is approximately 1.5 times the roll angle in rough weather, the wing tanks must be of sufficient height.

[0026] The center tank 3 and the equipment room within the center tank are essential equipment when the ART width exceeds 30m, but its width, height, length, etc. need only be sufficient to accommodate the amount of water in the DW-type wing tanks 2p, 2s on one side during rolling, satisfying the design conditions of the customer, and its dimensions depend on the design concept. (1) The purpose of installing the center tank is to create two sets of virtual tanks 1p and 1s. (2) The equipment room in the center tank is provided for the purpose of creating a virtual tank and disabling its function. (3) The height dimension of the equipment room shall be higher than the average water level of the tank body, and its upper end shall be equal to or higher than the top plate of the center tank. Lower it by taking any arbitrary interval. (a) The purpose is to make the liquid w flowing in from the liquid passages 6p, 6s overflow from the top of the equipment room when the angle of oscillation is large and exceeds the top of the equipment room, and to make the liquid overflow from the top end into the adjacent virtual tank. (4) At the center of the hull below the equipment room, one longitudinal bulkhead 5 in the bow-stern direction is provided between the bottom plate and top plate of the liquid passage, and the longitudinal bulkhead 5 is provided with the required opening area and a remote-operated gate 5c for opening and closing the opening 5o. (a) The purpose of gate 5c is to act as a means for closing the opening to allow the functions of the center tank and virtual tanks 1p, 1s to be exercised, and for releasing the functions of the center tank and virtual tank when the gate is opened. (b) Furthermore, since the moving liquid repeatedly reverses its flow every half of a vibration at a preset speed (period), there is no need to make the gate watertight from a cost-effectiveness standpoint. (c) It is desirable that the left-right width dimension of the equipment room be wider than the width of gate 5c. (d) In addition, hanging pieces for the insertion of equipment to be installed in the equipment room, and for maintenance, inspection, repair and work, as well as entrances and exits at necessary locations will be provided.

[0027] The liquid passages 6p, 6s connect the left and right outer plates 3p, 3s of the center tank 3 to the inner outer plate 2b of the wing tank, and one pair of liquid passages 6p, 6s is provided on each side. (1) It is desirable to plan the height of the liquid passages 6p, 6s to be as low as possible. (a) The purpose is that the liquid passage height determines the liquid level (water level) Wh throughout the tank and the basic height of the wing tank. (b) In addition, since the volume of liquid that is accounted for by the volume of the liquid passage (longitudinal cross-sectional area x width of the liquid passage) is approximately 60 to 70% of the total amount of liquid required, the aim is to make the liquid passage low and reduce the amount of liquid used. (c) Incidentally, it is desirable that the minimum height of the liquid passage be approximately 0.70 m or more to facilitate welding and maintenance, inspection and repair work, but there is no need to be so bound by this figure depending on the design concept. (d) It is especially important to note that it is desirable to make the bottom plate of the liquid passage parallel to its top plate. (2) It is desirable that the length of the liquid passage in the bow-stern direction be the same as the length of the wing tank. (a) Under some conditions, the calculated liquid passage height may be less than 0.50 m. (b) In this case, the height dimension of the liquid passage can be increased and the length of the passage can be made shorter than the length of the wing tank as a means of ensuring the required longitudinal cross-sectional area of ​​the liquid passage. (3) Inside the liquid passage, at any point in the bow-stern direction, there are at least three sets of passages separated by floor boards or the like, and the required number of lower dampers 8d1, 8d2, and at the point where the dampers are stopped, a pair of baffles are provided centered on the damper axis as a means of preventing turbulence of the liquid passing around the dampers. (4) The damper 8d is a hydraulic remote-operated type that can open from 0 to 90 degrees clockwise around a vertical axis and can stop at least one point along the way. A sensor is attached to confirm the stopping position, and a means is provided to transmit the damper's fully closed, half-stopped, or fully open position via an electrical signal to the control unit. (a) The purpose of using a hydraulic drive source is the inventor's design concept that requires instantaneous action to respond to suddenly changing roll cycles, particularly parametric roll, but it is also possible to use other drive systems. (b) Incidentally, the technology relating to dampers is well known, and detailed description thereof will be omitted in this application.

[0028] The air duct 7 (also called air duct 7a, 7b) is a means for controlling the liquid braking (activation or deactivation) of the ART and for varying the tank natural period Tts, and is directly connected to the divided left and right symmetrical positions of the DW type wing tank via a remotely operated closing device 7v near the top of the wing tank. (1) In the embodiment, two pairs of air ducts 7a, 7b are provided via hydraulically operated valves 7v. (a) The inside of the tank is sealed, and when the valve 7v with the air duct is closed, the air circulation between the left and right tanks is cut off and the movement of liquid stops. This state is called the ART inoperative. (b) When both air ducts 7a, 7b are opened, 2it, 2ot in the DW type wing tanks become one tank 2p, 2s on each side. In this state, the apparent liquid passage width is short and the wing tank width is wide. Functionally, a long tank natural period Tts is obtained and at the same time, a large anti-rolling force is obtained. Incidentally, the wider the wing tank, the greater the weight reduction force (anti-rolling moment). (c) When air duct 7a is opened and air duct 7b is closed (X7vc in the figure), liquid can move only in the outer tank 2ot, which is divided into two parts in the wing tank. In this state, the liquid passage is long and the width of the wing tank is shortened, and functionally, a short tank natural period Tts is obtained. The purpose is a special control means that lowers the height of the liquid passage to correspond to the slow rolling period range of 25.5 to 34 seconds in this embodiment (shown in Figure 5). (d) There may be a contradiction between the descriptions of the tank's natural periods in the previous paragraphs (b) and (c). However, when selecting the previous paragraph (b), the tank width is 25.0 m and the liquid travel distance is short, while in the previous paragraph (c), the tank width is 50.0 m and the liquid travel distance is long. In these different liquid passages, this is a novel means, not available in the prior art, of making the liquid passage heights of the previous paragraphs (b) and (c) the same. (2) The shape of the air duct 7 may be round (pipe) or rectangular, and its cross-sectional area (also called caliber) is determined by calculating the air flow velocity from the liquid flow velocity and appropriately determining the caliber that does not generate noise. (a) When a single caliber is larger, multiple smaller caliber air ducts may be used, taking into consideration the cost, the structure of the wing tank, etc., and providing the required cross-sectional area can be secured. (b) It is preferable that the air duct be a straight pipe type as shown in FIG. 1, but if this is difficult due to the surrounding environment, a U-shaped type (Patent Document 4) is also acceptable. (c) An air pipe that is open to the atmosphere may be used. In this case, however, the liquid in the tank will splash and flow out, so water will be poured in as necessary. (3) Furthermore, the center tank 3 is part of the liquid passage, and it has been found that no significant effect can be obtained by connecting the center tank to the left and right wing tanks with air communication pipes.

[0029] Although not shown in the figure, the ART main body 1 is equipped with all the necessary equipment for a tank, such as equipment for filling and draining the liquid to be used, a depth sounding pipe (liquid level gauge), a water level adjustment pipe, and an air vent pipe, and all pipes leading to the outside are provided with closing means to enable the inside of the tank to be kept airtight.

[0030] Here, in order to make the technical supplement for lowering the height of the liquid passages 6p, 6s of the present invention easier to understand, the overlapping points will be also described. (1) Distance traveled by liquid (a) The moving distance is the distance between the centers of gravity of the moving liquid, but in this embodiment it is simply the moving distance traveled back and forth across the entire width of the tank. (b) For ART main unit 1, 50.0m x 2 = 100.0m. (c) For hypothetical tanks 1p and 1s, each is 25.0 m x 2 = 50.0 m. (2) Time required to transfer liquid (a) A single roll refers to a situation in which, for example, the ship goes from horizontal to list downward on the port side, then returns to the original horizontal position due to the ship's stability, and then, when acceleration is applied, the ship lists upward on the starboard side, and then returns to the original horizontal position. (b) Passive ART utilizes the natural phenomenon of liquid flow from higher to lower elevations. In the process of liquid movement reversing, for example, the flow rate gradually slows down from its maximum, stops, then gradually speeds up in the reverse direction, and finally reaches its maximum flow rate. The time it takes for one oscillation to complete one cycle is the time required for the liquid to move. (3) Mean flow velocity (a) The shortest tank natural period required in this embodiment is 20 seconds. (b) The average flow velocity within the ART body (50 m wide) is 100 / 20 = 5.0 m / s. (c) For a hypothetical tank (25 m wide), the average flow velocity is 50 / 20 = 2.5 m / s. (4) Height of liquid passage (a) The liquid passage height required for the flow velocity value of 5.0 m / sec in the previous paragraph (b) is approximately 2.5 m. (b) The liquid passage height required for the flow velocity of 2.5 m / sec in the previous paragraph (c) is approximately 0.9 m. (c) Therefore, in this embodiment, a virtual tank (liquid passage height: approximately 0.9 m) is adopted. (5) The functional tank selection criteria are: long rolling period ≥ threshold (25.5 s) ≥ short rolling period. (a) The virtual tank is used when the threshold (25.5 seconds) is greater than or equal to the ship's average period. (b) The ART main unit is used when the ship's average period is greater than or equal to the threshold (25.5 seconds). (6) Tank anti-rolling effective roll period range (also simply called effective roll period range) (a) The effective roll period range for the hypothetical tank is 18.5 to 26 seconds. (b) The effective roll period range for reducing roll of the tank body shall be 25.5 to 34 seconds.

[0031] The basic control method for creating a virtual tank is as follows: (1) An example of the shape of a hypothetical tank (a) The shape of the imaginary tank 1p is the port wing tank 2p, the liquid passage 6p, and the longitudinal bulkhead 5 in the center tank 3, and is also called the port side tank. (b) The shape of the imaginary tank 1s is the starboard side of the longitudinal bulkhead in the center tank, the liquid passage 6s, and the starboard wing tank 2s, and is also called the starboard side tank. (c) By executing the following steps (d) to (f), a virtual tank will be constructed, the shape of which is shown in Figure 3. (d) Close the opening closure device 5c of the longitudinal bulkhead installed below the equipment room in the center tank. (e) The damper 8d1 in the liquid passage 6s is closed, and the damper 8d2 is opened. (f) Open valve 7v of air ducts 7a and 7b. (2) Virtual Tank Function (a) The effective roll period range for the hypothetical tank is 18.5 to 26.0 seconds. (b) Create a control group (CASE1-4) including the tank natural period Tts. (c) The reason why the roll period STs becomes shorter during voyage is when the ship encounters head seas, and the apparent GoM value also becomes larger. To deal with this, the tank's anti-rolling force TMt needs to be increased, so the wider wing tanks 2p and 2s are used for this purpose. (d) Cases 1 to 2 are used to deal with short periods that occur in head waves (including parametric rolling). (3) Liquid movement in the hypothetical tank For example, when the ship's hull rolls (inclines) to the starboard side, (a) In the imaginary tank 1p, liquid w in the port side wing tank 2p flows into the center tank 3 through the liquid passage 6p. (b) In the virtual tank 1s, liquid in the center tank moves into the starboard wing tank 2s via the liquid passage 4s. (c) Figure 4 shows the state of the liquid after going from starboard listing to horizontal (1 / 2 turn). (4) In addition, in Figures 3 and 4, since the wing tanks 2it and 2ot are used as a single wing tank 2p, 2s, the longitudinal bulkhead 2bh within the DW type wing tank is shown as an imaginary line.

[0032] The basic control method for the ART main unit 1 is as follows. (1) Shape of the ART body (a) Open the gate 5c attached to the vertical bulkhead 5 below the equipment room in the center tank 3. (b) The dampers 8d1 and 8d2 in the liquid passage 6s are opened. (c) Air duct 7a is opened and air duct 7b is closed. (d) By executing the previous steps (a) to (c), the ART body shape is constructed. (e) The state of the previous paragraph (d) is shown in Figure 5, but since a separate outer wing tank 2ot is to be constructed, the inner skin 2b of the DW type wing tank is shown in virtual lines. (f) If the set rolling period is long, for example 36 seconds, it is possible to accommodate this by opening the air duct 7b from the state described in (c) above. (2) Functions of the ART unit (a) The effective roll period range for the ART body is 25.5 to 34.0 seconds. (b) Create a control group (Cases 5-9) that includes the tank natural period. (c) The reason why the roll period STs becomes longer during navigation is when the ship encounters following seas, which makes the apparent GoM value smaller. Since the corresponding anti-rolling force does not need to be large, wing tank 2ot is used for this purpose. (d) Cases 8 to 9 are used to deal with long periods of following waves (including parametric rolling). (3) Fluid movement status of the ART body (a) When the gate 5c on the longitudinal bulkhead 5 is opened to release the center tank function, the liquid passages 6p, 6s become the liquid passage 4, and the liquid w in the port wing tank moves directly to the starboard wing tank. (b) Figure 6 shows the state of the liquid after the vessel has gone through a starboard list and is now horizontal (1 / 2 turn).

[0033] The configuration of the control device can be broadly divided into an information analysis section including an inclination sensor, etc., a control section that issues pre-set drive commands for the equipment, and the opening and closing equipment device section, etc., but these are publicly known technologies in the ART (paragraphs 0013-0034 of cited patent 1), so individual illustrations and details are omitted. (1) Understanding ship motion information in the example Data related to ship motion (pitch, roll, wind direction, wind speed, ship speed, etc.) is collected in an analog manner (continuously). This technology is described in detail by the inventor of the present application in Patent Document 3. (2) Means of analyzing information on the ship's motion From the collected continuous data, the calculation and decoding circuit uses the moving average method to calculate 1 / 2 of one swing, the angle and period of one swing, and also prediction information for the next swing. Incidentally, the point at which the ongoing swing reverses is considered to be 1 / 2 of one swing. (3) Control of the device A control circuit outputs a control signal from a control section including a circuit that executes optimal processing based on an execution circuit and feedback information on the execution results of the device. (4) Variable tank natural period Tts in DW-type ART and fluid damping equipment By combining the air duct-equipped closing device 7v, the vertical bulkhead opening closing device 5c, and the opening and closing of the lower damper 8d which adjusts the liquid movement speed, it is possible to vary the tank natural period Tts and apply liquid braking as necessary, and this is usually performed by automatic control. (5) Construction of each control group When a predetermined control execution program is executed, control groups CASE1 to CASE9 are constructed, and from among these, the CASE that is most suitable for the moving average roll period value ATs of the encountered ship is selected and executed.

[0034] The control group is composed of control groups CASE1 to CASE9, with an effective period range of about 3 seconds including each tank's natural period value Tts that exhibits high roll reduction efficiency referred to as one group (CASE). (1) Based on the rolling period that changes with each rolling encountered, the average rolling period ATs is calculated by taking a moving average of multiple values, and the optimal control group is selected. In this embodiment, an overlap value of 0.5 seconds is set so that chattering of the device does not occur when switching between the group and the adjacent group, but this overlap value differs depending on the conditions of each ship and is determined appropriately by the designer. (2) The control specifications for the open / closed combinations of the dampers 8d1, 8d2, the gate 5c, and the valves 7v that form each control group are established for each ship, and the means for this embodiment are shown in the following table.

[0035] [Table 2]

[0036] From this paragraph onwards, we will discuss parametric roll. (1) Non-patent document 2 contains the following description of the dangers of parametric roll and the reasons for it: (a) Container ships are a type of ship that is susceptible to the effects of parametric rolling in following sea conditions. (b) Depending on the ship's roll period, the ship's speed, course and the angle at which the ship meets the waves, the ship's roll angle may suddenly increase to a level which endangers the safety of the ship, its crew and its cargo. (c) This phenomenon is known to occur even with relatively gentle wave heights. (2) Parametric roll can occur in the following situations: Ship oscillations are induced when the ship's natural rolling period FTs during operation coincides with the period of encounter with waves. (a) When the roll period is approximately twice the pitch period. (b) When the wavelength is within the length of the ship. (c) It can also occur in head waves in rough weather or following sea conditions that result in a long rolling period.

[0037] Parametric roll oscillation causes and prediction (a) Paragraph 0023 of this application states that the ship's roll period STs, pitch period APs, roll angle ATθ, pitch angle APθ, etc. are constantly monitored as the motion information necessary to predict the occurrence of parametric roll. (b) Compare the values ​​of the roll angle ATθ over time and monitor the increase in the roll angle. (c) Compare the values ​​of the average roll period ATs over time and monitor the increase in the roll period. (d) Monitor the ratio of pitch to roll periods and monitor whether the ratio is moving toward 1:2. (e) Based on the ship speed during the voyage and the propeller RPM information, if the ship speed slows down it is considered to be head waves, and if it speeds up it is considered to be following waves.

[0038] If the possibility of parametric roll occurrence is foreseen, the following measures can be taken to avoid it: (a) Notify the operator by means of an alarm buzzer, screen display, or voice, etc. (b) Changing the propeller speed and pitch of variable propellers as an emergency response measure. (c) Change course to change the angle and period of encounter with the waves to avoid the occurrence of parametric rolling. (d) The above operations are performed by known means and are manual operations in accordance with a predetermined ship operating manual.

[0039] The situation as to whether or not parametric roll will occur is constantly monitored as described in paragraph 0037. (1) The difference between parametric rolling and rolling during stormy weather is the magnitude of the amplitude. (a) The parametric roll angle can be 1.5 to 2 times greater than the roll angle in rough weather. (b) Parametric roll and rough weather roll have different roll period values. (c) The parametric rolling period in head sea conditions becomes shorter. (d) The parametric rolling period becomes longer in following sea conditions. (e) Parametric rolling occurs when a ship encounters head waves and following seas. (2) Responses in the event of a parametric rolling state as described in the present application; (a) Cases 1 and 2 are used to deal with the short period parametric rolling that occurs in head waves. (b) Cases 8 to 9 deal with the long period parametric rolling motion that occurs during following waves. (c) The selection and execution of the preceding paragraphs (a) and (b) can be performed instantaneously, as described in claim 5. (e) In addition, automatic control will be possible by prior coordination with the main engine or steering gear manufacturer. (f) Furthermore, even if the roll period suddenly changes due to the operations in (b) to (e) above, the ART's effective roll reduction period range is set to 18.5 to 34 seconds, and the most appropriate control group is automatically selected and executed from the applicable control groups (CASE 1 to 9), so no problem will arise. [Industrial Applicability]

[0040] The present invention is based on the design concept and technological improvements of large ships that have a proven track record when equipped with ARTs with a width of 30m, and is a motion reduction tank device and control method for huge container ships with a width of 50m, which has great industrial potential for reducing rolling and parametric rolling in rough weather, and even avoiding parametric rolling. [Explanation of symbols]

[0041] 1 ART main body (mountain-shaped anti-roll tank) 1p Virtual Tank (Port) 1s Virtual Tank (starboard) 2p DW type wing tank (port side) 2s DW type wing tank (starboard) 2b Inner skin of DW type wing tank Longitudinal bulkhead in bow-stern direction in 2bh DW type wing tank 2it split inner wing tank 2ot split outer wing tank 3. Center Tank 3t center tank top plate 3p Left outer panel of center tank 3s Right outer panel of center tank 4. Equipment room in center tank 4d Equipment room entrance 4t equipment room top plate 4t1 Equipment room inclined top plate 4p Equipment room longitudinal bulkhead (port side) 4s Equipment room vertical bulkhead (starboard) 4b Gap between the top plate of the equipment room and the top plate of the center tank 5. A vertical bulkhead between the bottom and top plates of the liquid passage at the center of the left and right direction below the equipment room 5o Opening in vertical bulkhead between bottom and top plates of liquid passage 5c. Closure device for longitudinal bulkhead opening (also called gate) 5g1 No.1 Gate 5g2 No.2 Gate 5g3 No.3 Gate 6 A liquid passageway that combines the port and starboard liquid passageways (also called the lower duct) 6t liquid passage top plate 6o Liquid passage top plate opening 6p Liquid passage (port side) 6s Liquid passage (starboard) 7 Air communication pipe (also called air duct) 7v Air ducted closure device (also called valve) 7a NO.1 Air Duct 7b No.2 air duct 7vc Valve closed 8d A closing device in a liquid passage that adjusts the speed at which the liquid moves (also called a lower damper) 8d1 No.1 Lower Damper 8d2 No.2 Lower Damper Wh Liquid level (water level) w liquid Mt Wave force inducing rolling of a ship FMt - The force that brings the ship back to its original position (also called the stability force) TMt Anti-rolling force (also called anti-rolling moment) in the water tank (also called tank) STs Ship rolling period FTs Natural period of ship's rolling motion ATs Mean rolling period of a ship Tts Tank natural period

Claims

1. The anti-rolling tank device is a U-tube type anti-rolling tank with DW-type wing tanks (2p, 2s) of the same dimensions on both sides of the hull, and is configured so that the cross-sectional shape of the ART body (1) is a mountain-shaped shape consisting of a center tank (3) located near the center of the hull, and a pair of liquid passages (6p, 6s) on each side for moving the liquid (w) in the anti-rolling tank in the left-right direction. The ART body (1) is configured so that the cross-sectional shape of the anti-rolling tank is a mountain-shaped shape consisting of an equipment room (4) in the center tank, a vertical bulkhead (5) with an opening below the equipment room, an opening / closing device (5c) for opening / closing the equipment (8d), the equipment (7v) for braking the liquid and adjusting the moving speed, and a device (8e) for adjusting the ship's rolling angle, etc. a control section including an inclination sensor for detecting tilt, an arithmetic circuit for decoding information output from the sensor, an information processing circuit, and a control execution circuit; and a device section for executing a preset control specification for driving the equipment based on the results decoded by the control section, characterized in that when the detected average roll period value is short (fast), the functions of a center tank (3) and virtual tanks (1p, 1s) are created, or when the detected average roll period value is long (slow), the functions of the center tank and virtual tank are eliminated.

2. In the center tank (3) that is essential for creating the virtual tanks (1p, 1s), there is an independent equipment room (4). and a vertical bulkhead (5) between the bottom plate and the top plate of the liquid passage at the center position in the transverse direction of the hull below the equipment room, an opening (5o) of a required area, and a closing device (5c) for the opening.

2. A vessel motion reducing tank apparatus according to claim 1.

3. 2. A water tank device for reducing ship motion as claimed in claim 1, comprising: a set of left and right liquid passages (6p, 6s) connecting the outer plates (3p, 3s) of the center tank and the inner outer plate (2b) of the DW type wing tank; at least three sets of passages (6) partitioned by floor boards or the like at any positions in the bow-stern direction within the passages; remote-operated lower dampers (8d1, 8d2) capable of obtaining a plurality of tank natural periods (Tts) by varying the longitudinal cross-sectional area of ​​the passages, which can be stopped at at least one position during opening and closing from 0 to 90 degrees clockwise, a sensor which transmits a position signal to a control unit; and a pair of baffles centered on the lower damper axis which prevent turbulent flow of liquid occurring near the tip of the wing when the lower dampers are stopped.

4. In the A.R.T main body (1) according to claims 1 to 3, instantaneous information on the rolling and pitching of the ship is detected in a time series, and based on the calculation results of predicting the period and angle of one roll, the moving average rolling period and average angle, and the period and angle of the next roll, etc. from that information, a control method is executed to execute drive control specifications for the opening closing device (5c) of the vertical bulkhead (5) as a means for responding to each average value encountered, the lower dampers (8d1, 8d2), and the air duct valve (7v), in which when the opening closing device of the vertical bulkhead and the lower damper No. 1 (8d1) are closed and the valve (7v) of the air duct (7a, 7b) is opened, the functions of the center tank and the virtual tank are exerted, and in this state, the lower damper No. When the opening and closing device (5c) and the lower damper (8d1) are opened in this state, the functions of the center tank and the virtual tank are released, and when the lower dampers (8d1, 8d2) are opened and closed with the air duct (7b) closed, control groups (CASE5-CASE9) corresponding to the ship's rolling period range of 25.5-34 seconds are formed, and the control group optimal for the moving average period value (ATs) encountered by the ship is automatically selected. The method for controlling a ship motion reduction tank apparatus as described in claim 1 further comprises the steps of: forcibly closing the air ducts (7a, 7b) to stop the movement of liquid (deactivating the A.R.T.) when a ship rolling period exceeding 34.5 seconds outside the set period is detected.

5. In the method for controlling a ship motion reduction tank apparatus according to claim 4, 2. A method for controlling a ship motion reduction tank device according to claim 1, further comprising the steps of: adding a program for predicting whether or not parametric rolling will occur to a program for analyzing a predicted period and angle of the next motion from information such as ship speed, wind direction and speed, pitch and roll angle, and their periods during the ship voyage; and, when it is determined that parametric rolling will occur, notifying the operator of the occurrence of the occurrence of parametric rolling by an alarm buzzer, a displayed alarm, or a voice, etc., in order to avoid parametric rolling; and, when parametric rolling has occurred, instantly driving the device which exerts the function of A.R.T. motion reduction.

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