Method of controlling stability of vessel in breaking waves

Abstract

FIELD: shipbuilding.SUBSTANCE: invention relates to methods for monitoring the stability of a vessel under operating conditions and can be used in the creation of navigation expert systems for monitoring the stability of a vessel in breaking waves. Vessel stability is controlled on the basis of wave parameter measurements and their prediction. The vessel's dynamics is simulated under current and predicted wave conditions in shallow water when breaking waves strike the side of the vessel, taking into account the features of the vessel's architecture, and determine the greatest angle of heel as a result of these impacts.EFFECT: predicting the stability of a vessel in conditions of breaking waves and increasing the safety of navigation.1 cl, 3 dwg

Description

[0001] The invention relates to shipbuilding, in particular to methods for monitoring the stability of a vessel under operating conditions, and can be used in the creation of navigation expert systems.

[0002] A method for monitoring the stability of a vessel is known (RU 2405712, IPC B63B 39 / 14, published on 10.12.2010), used to monitor stability in conditions of deck flooding in a following sea, based on measuring the period of rolling and determining by calculation the metacentric height, in the calculation of which the draft of the vessel bow and stern, the course angle and speed of the vessel in irregular waves, wind speed, the coordinates of the vessel's position and the distance to the nearest port of refuge are additionally measured, and when assessing the stability of the vessel under the current state of the load, the thickness of the water layer in the deck well for the forward position of the vessel is additionally measured, on the basis of which the arm of the heeling moment from the water poured onto the deck is determined, and according to the measured values ​​of the angle of entry of the edge of the bulwark into the water, the angle of heel, draft bow and stern, the displacement is calculated vessel and the current heeling moment,the value of which is presented in the form of a graphical dependence on the angle of heel for comparison with the limiting, critical diagram of the vessel's stability at the top of the wave, calculated taking into account the standardized wave parameters, and the stability assessment is carried out according to a criterion based on the calculation of the actual applicate of the center of gravity of the vessel for the current diagram of stability at the top of the wave, the value of which should not exceed the critical applicate of the center of gravity of the vessel for the limiting diagram.

[0003] A significant disadvantage of this method of monitoring the stability of a vessel is the impossibility of using it to monitor the stability of a vessel in breaking waves.

[0004] A method is known for predicting the pitching of a vessel during the landing of aircraft in marine conditions (RU 2571389, IPC G 06 N 3 / 02, G 05 D 1 / 00, published on 20.12.2015), implemented using the competition principle and including measuring the current angular movements of the vessel's deck and forming, on the basis of previous and subsequent movements, a pitching model using extrapolation methods and measuring the values ​​​​of the speeds of movements during rolling and pitching, comparing the values ​​​​of movements and speeds of movements with the maximum permissible values ​​​​of the amplitudes of rolling and pitching, specified from the condition of a safe landing, determining the area of ​​​​insignificant pitching based on the results of the comparison, adjusting the predicted model and signaling to the pilot about the moments of the beginning and end of takeoff and landing operations in specified weather conditions.

[0005] This method for predicting the pitching of a vessel during the landing of aircraft in marine conditions has the disadvantage that it does not take into account the dynamics of the interaction of a vessel with breaking waves, which does not allow it to be used to monitor the stability of vessels in shallow water in the wave breaking zone.

[0006] A method is known for operational control of the stability of a vessel in emergency situations (RU 2631127, IPC G06F 17 / 50, B63 B 39 / 14, published on 19.09.2017), implemented on the basis of intelligent technologies, methods of the dynamic theory of catastrophes and high-performance computing tools, during the implementation of which variants of the functional and organizational structure of the control system of the on-board intelligent system are generated based on the principles of formalization of the logical system of knowledge in conditions of uncertainty and incompleteness of the initial information, an assessment of the results of the generation of conceptual solutions is performed based on the criteria for ensuring the safety of navigation.

[0007] This method of operational control of the stability of a vessel in emergency situations has a significant drawback, which is the impossibility of using it to control the stability of a vessel under the influence of breaking waves.

[0008] A method for monitoring the stability and speed of a vessel is known (RU 2259301, IPC B 63 B 39 / 14, published on 27.08.2005), which consists of measuring the period of rolling and determining by calculation the metacentric height, during the calculation of which the draft of the vessel by the bow and stern, the apparent wave period, the course angle, the speed of the vessel in irregular waves, the speed of the apparent wind, the air temperature and the temperature of the seawater are measured, while when determining the speed of the vessel in ice conditions, the thickness of the ice, the thickness of the snow cover, the thickness of the outer plating and the thickness of the hull framing in the bow of the vessel in the contact zone are additionally measured, the actual condition of the hull, characterized by a decrease in the thickness of the plating and framing as a result of wear, is established, and the safe speed of the vessel is determined.

[0009] The disadvantage of this method is that it does not allow for monitoring the stability of the vessel in shallow water conditions, where the vessel may be subject to impacts from breaking waves that have a significant reserve of kinetic energy.

[0010] A method for monitoring the stability of a vessel is known (RU 2043271, IPC B65 B39 / 14, published 10.09.1995), which consists of measuring the period of rolling and determining the metacentric height by calculation, wherein when determining the metacentric height, the draft of the bow and stern, the apparent wave period, the course angle, the speed of the vessel in irregular waves, the speed of the apparent wind, the air temperature and the temperature of the seawater are additionally measured.

[0011] The disadvantage of this method is that it does not allow for monitoring the stability of the vessel in breaking waves.

[0012] A known method for monitoring the stability of a vessel (RU 2740617, IPC B 63 B 39 / 14, B 63 B 39 / 00, G 05 D 1 / 00, published on 15.01.2021) is carried out on the basis of data from measuring wave parameters and predicting them, within the framework of which the dynamics of the vessel are modeled under predicted wave conditions, taking into account the possibility of the bow being captured by a wave in head-on waves, the loads acting on the bow being flown around due to immersion in a wave are determined, the transverse metacentric height is determined, and a static stability diagram is constructed under capture conditions, which are compared with regulatory requirements.

[0013] The disadvantage of this method is that it does not allow for an assessment of the vessel's stability under conditions of breaking waves.

[0014] The closest analogue is the method for monitoring the stability of a vessel in breaking waves (RU 2455190, IPC B 63 B 39 / 14, B 63 B 39 / 00, published on 10.07.2012), based on measuring the period of rolling and determining the metacentric height by calculation, during the calculation of which the draft of the vessel by the bow and stern, the "apparent" period of the wave, the course angle and the speed of the vessel in irregular waves are additionally measured, when assessing stability in conditions of breaking waves in a given navigation area under the current state of the vessel's load, the angular velocity during rolling, the depth of water under the keel of the vessel and the parameters of the waves deformed in shallow water are additionally measured, on the basis of which the characteristics of the impact of breaking waves are calculated, the actual indicators of the dynamics of the interaction of the vessel with the external environment and the possibility of the vessel capsizing at the moment of impact of a breaking wave and in conditions of a rapid drift from the impact of a breaking wave.

[0015] This method of monitoring the stability of a vessel in breaking waves has a significant drawback, consisting in the fact that it does not take into account the architectural and structural features of the vessel, which does not allow it to be used for an objective assessment of the safety of the vessel in breaking waves. Thus, an increase in the height and length of the superstructure can significantly increase the applicate of the point of application of the resulting force of hydrodynamic pressure when a breaking wave hits the side. In addition, the presence of a deck well on the vessel can lead to its flooding with water when hit by a breaking wave, the crest of which is located above the upper edge of the bulwark (Burakovsky E.P., Burakovsky P.E., Verevochkin A.V., Yusyp V.M. The influence of ship architectural features in assessing their stability in breaking waves under conditions of deck flooding / / Marine intellectual technologies. - 2025. - No. 1, part 1. - pp. 33-40).In addition, this method allows the vessel to be assessed only after it has entered the zone of action of breaking waves, as a result of which it may capsize even before the navigator has time to take it to a safe area, in the event that the stability assessment using this method shows that the vessel's stability is not ensured.

[0016] The invention solves the problem of increasing the safety of navigation by more accurately preventing possible dangerous situations associated with the loss of stability of a vessel in breaking waves, by taking into account a wider range of factors influencing the stability of a vessel, which are used in calculations, namely, the predicted parameters of sea waves, the pitching of a vessel in actual and predicted waves, and the architectural and structural features of the vessel.

[0017] In order to obtain the required technical result, in the method of monitoring the stability of a vessel in breaking waves, which consists of measuring the period of rolling and determining by calculation the metacentric height, in the calculation of which the draft of the vessel by the bow and stern, the "apparent" period of the wave, the course angle and the speed of the vessel in irregular waves are additionally measured, as well as measuring the angular velocity during rolling, the depth of water under the keel of the vessel and the parameters of the waves deformed in shallow water, calculating the characteristics of the impact of breaking waves and determining the actual indicators of the dynamics of the interaction of the vessel with the external environment and the possibility of capsizing the vessel at the moment of impact of a breaking wave and in conditions of rapid drift from the impact of a breaking wave, it is proposed to carry out a forecast of the parameters of sea waves,determine the characteristics of the impact of breaking waves under predicted wave conditions and model the dynamics of the vessel when struck by a breaking wave taking into account the length and height of the superstructure and the presence of a deck well, after which determine the greatest angle of heel as a result of the impact of the breaking wave and draw a conclusion about the stability of the vessel in the predicted breaking waves, and judge the loss of stability of the vessel when the following condition is met:,

[0018] where - the greatest angle of heel as a result of the impact of a breaking wave, degrees;

[0019] - the angle of flooding at which water floods the internal spaces of the vessel through openings considered open, or openings that may be open in the working condition of the vessel under operating conditions, in degrees.

[0020] The proposed method for monitoring the stability of a vessel, based on measurement data, predicts the parameters of sea waves, determines the magnitude of impact loads from the impact of breaking waves, and models the dynamics of the vessel under the action of such loads, taking into account the height and length of the superstructures and the presence of a deck well, as a result of which the greatest angle of heel of the vessel is determined.

[0021] The attached graphic materials show:

[0022] in Fig. 1 - the dependence of the heeling moment arising during the drift of the vessel on time, used in the implementation of the method of monitoring the stability of the vessel in accordance with the closest analogue;

[0023] in Fig. 2 - the dependence of the restoring moment on the angle of heel (the diagram of the static stability of the vessel), used in the implementation of the method of monitoring the stability of the vessel in accordance with the closest analogue;

[0024] Fig. 3 - dependence of the calculated angle of heel of the vessel on time when monitoring the stability of the vessel using the proposed method.

[0025] The following symbols are used in graphic materials:

[0026] - time, s;

[0027] - bank angle, degrees;

[0028] - restoring moment, kN⋅m;

[0029] - heeling moment acting on a vessel under the impact of a breaking wave and the resulting drift, kN⋅m.

[0030] The vessel stability monitoring method is implemented as follows. Using sensors, the wave heading angle, apparent wave period, bow and stern draft, vessel speed in waves, apparent wind speed, and the vessel's roll period are measured. Based on the bow and stern draft measurements and the vessel's theoretical drawing, the coordinates of the center of gravity are calculated. The transverse metacentric height and the position of the center of gravity are determined by analyzing the vessel's roll. Then, using the data from the theoretical drawing, a static stability diagram is constructed for the vessel's given loading conditions.

[0031] Based on wave measurement data and using weather forecast, a forecast is made of sea wave parameters for the area of ​​the world ocean where the vessel is located.

[0032] To predict sea wave parameters, one can use, for example, a device for measuring and predicting sea wave parameters (Patent for Utility Model No. 139053, IPC G01S 13 / 58, published on April 10, 2014), which allows predicting sea wave parameters in both the short-term and long-term mode.

[0033] Short-term forecasting mode is based on the analysis of data samples over a time range specified via the control unit. The forecast depth in this case is no more than two hours.

[0034] Long-term forecasting mode is implemented using data from a weather forecast data receiver unit, such as a navigation telex with a digital interface. In this case, sea wave parameters are forecast based on knowledge analysis using a production system. The forecast depth range in this mode is extended to twenty-four hours. The forecast depth value is set by the operator via the control unit.

[0035] Then, for the parameters of sea waves obtained as a result of forecasting, the parameters of waves in shallow water are calculated and the values ​​of impact loads under the influence of breaking waves are determined according to (A.N. Kholodilina, A.N. Shmyrev. Seaworthiness and stabilization of ships in waves. L.: Sudostroenie, 1976, pp. 307-327).

[0036] Next, the vessel dynamics are modeled using the methodology (Burakovsky E.P., Burakovsky P.E., Verevochkin A.V., Yusyp V.M. The influence of ship architecture features in assessing their stability in breaking waves under conditions of deck flooding / / Marine intellectual technologies. - 2025. - No. 1, part 1. - P.33-40), which allows taking into account the characteristics of the vessel's superstructure and other features of its architecture.

[0037] As an example of the implementation of the proposed method for monitoring the stability of a vessel in breaking waves, we will consider the stability of a trawler with a light displacement of 1800 t, a length of Z = 50.6 m, and a width of 12 m under the influence of breaking waves. We will consider a case where the vessel's design includes a deck well, the length of which is L / 2, and the height of the bulwark is The implementation of the proposed method can be presented in the form of a series of stages.

[0038] Stage 1. Measuring the period of rolling and determining the metacentric height by calculation, during the calculation of which the vessel's bow and stern drafts, the "apparent" wave period, the course angle and speed of the vessel in irregular waves are additionally measured, and the angular velocity during rolling is additionally measured.

[0039] Let the transverse metacentric height, determined based on the results of measuring the roll period, bow and stern draft, apparent wave period, heading angle, vessel speed in irregular waves, and the ordinates of the wave and roll processes, be h = 1.0 m. In this case, the coordinates of the center of magnitude can be determined based on the theoretical drawing, and the applicate of the center of gravity of the vessel for the current loading conditions can be calculated for this metacentric height. Let the average draft in the case under consideration be applicate of the transverse metacenter center of gravity applicate ; waterline area S=490 m2 ; coefficient of total completeness δ=0.609; coefficient of waterline completeness α=0.878. Dependence of the righting moment on the heel angle (the static stability diagram) of the vessel in question is shown in Fig. 1, the flooding angle for the vessel in question is Attached masses and moments of inertia for a given vessel in the case under consideration We will take the depth of the water area in which the vessel stability control is performed as 12.5 m.

[0040] These data can be used in modeling the dynamics of a vessel according to (Burakovsky E.P., Burakovsky P.E., Verevochkin A.V., Yusyp V.M. The influence of ship architecture features in assessing their stability in breaking waves under conditions of deck flooding / / Marine intellectual technologies. - 2025. - No. 1, part 1. - P.33-40), as well as in implementing the stability control method according to the closest analogue.

[0041] Stage 2. Forecasting sea wave parameters. Let's assume, based on current wave parameter measurements and a weather forecast, that the maximum breaking wave height of a given probability level in the planned operating area is m, and the calculated depth of the reservoir, taken as equal to the depth of the water area under the base of the periodic waves

[0042] Stage 3. Determination of the characteristics of the impact of breaking waves under predicted wave conditions.

[0043] Maximum Strength and the time of impact breaking wave can be determined using dependencies (A.N. Kholodilina, A.N. Shmyrev. Seaworthiness and stabilization of ships in rough seas. L.: Sudostroenie, 1976, pp. 307-327):

[0044]

[0045] where - the maximum value of acceleration in a single wave, determined depending on the relative height of the wave γ;

[0046] - coefficient depending on the relative wave height γ;

[0047] - relative height of a single wave;

[0048] - height of a single wave;

[0049] - the calculated depth of the reservoir, taken as equal to the depth of the water area under the base of the periodic waves.

[0050] According to (A.N. Kholodilin, A.N. Shmyrev. Seaworthiness and stabilization of ships in rough seas. L.: Sudostroenie, 1976, pp. 307-327) in the case under consideration it can be assumed that then, taking into account (1) and (2), we obtain:

[0051]

[0052] Assuming that the force of the impact increases according to a law close to a triangular one, and considering that the start time of the impact coincides with the start of the count, we can write the following expression for P(t)

[0053]

[0054] Next, to take into account the architectural and structural features of the vessel, this force is broken down into components operating on sections of the hull with guard rails, bulwarks and superstructure, respectively, depending on the length.

[0055] Stage 4. Modeling the dynamics of a vessel when struck by a breaking wave, taking into account the length and height of the superstructure and the presence of a deck well.

[0056] The modeling of the vessel dynamics when impacted by a breaking wave is carried out according to (Burakovsky E.P., Burakovsky P.E., Verevochkin A.V., Yusyp V.M. The influence of ship architecture features in assessing their stability in breaking waves under conditions of deck flooding / / Marine intellectual technologies. - 2025. - No. 1, part 1. - P.33-40).

[0057]

[0058] where - transverse displacement of the vessel (lateral drift), m;

[0059] - vessel displacement, t;

[0060] - added mass in the direction of drift, t;

[0061] - the attached static moment relative to the longitudinal central axis, t⋅m;

[0062] - the resistance force to ship drift, kN;

[0063] - the moment of inertia of the vessel relative to the longitudinal axis passing through the center of gravity of the vessel, t⋅m 2 ;

[0064] - the added moment of inertia relative to the same axis, t⋅m 2 ;

[0065] - damping moment during roll, kN⋅m;

[0066] - heeling moment acting on a vessel under the impact of a breaking wave and the resulting drift, kN⋅m;

[0067] - additional heeling moment acting on the vessel due to the impact of water masses on the bulwark from the side opposite to the side subject to the impact of the breaking wave, kN⋅m;

[0068] - additional heeling moment acting on the vessel due to the deck being loaded with water, kN⋅m;

[0069] - restoring moment determined by adjusting the dependence taking into account the transformation of the waterline due to the increase in water level on one side upon the approach and impact of a breaking wave, kN⋅m;

[0070] - components of the force of impact of a breaking wave on the side, kN;

[0071] - the force of the impact of the water masses on the bulwark from the inside of the side opposite to the side exposed to the breaking wave, kN.

[0072] Heeling moment acting on a vessel in drift conditions after the impact of a breaking wave, taking into account the architectural and structural features of the vessel, can be determined from the condition:

[0073]

[0074] where - components of the impact force of a breaking wave acting on sections of the hull with guard rails, bulwarks and superstructure, respectively, kN;

[0075] - the applicate of the point of intersection of the line of action of the drift resistance force with the centerline of the vessel, m;

[0076] - applicates of the points of intersection of the line of action of the above components of the wave impact force with the centerline of the vessel, m;

[0077] - applicate of the vessel's center of gravity, m.

[0078] The drift resistance force can be determined according to the recommendations given in [6]:

[0079]

[0080] where L is the length of the vessel, m;

[0081] T - vessel draft, m;

[0082] ρ - water density, t / m 3 ;

[0083] - a hydrodynamic coefficient depending on the ratio of the main dimensions of the vessel, the coefficient of overall completeness and the angle of heel, determined by the regression models presented in (Nechayev Yu.I. Modeling of stability in waves. Modern trends. L.: Shipbuilding, 1989. 240 p.). Then

[0084]

[0085] where factors used in constructing the regression model;

[0086] - coefficient of total completeness.

[0087] To calculate the applicate z q You can also use regression models [6]:

[0088]

[0089] where - the value of the conventional heeling moment arm, related to the vessel's draft.

[0090] The remaining components included in the system of equations (4) are determined according to (Burakovsky E.P., Burakovsky P.E., Verevochkin A.V., Yusyp V.M. The influence of ship architecture features in assessing their stability in breaking waves under conditions of deck flooding / / Marine intellectual technologies. - 2025. - No. 1, part 1. - P.33-40).

[0091] The results of modeling the dynamics of a vessel when it is hit on the side by a breaking wave are shown in Fig. 3.

[0092] Stage 5. Determining the maximum angle of heel as a result of the impact of a breaking wave and concluding on the stability of the vessel in the predicted breaking waves.

[0093] As can be seen from Fig. 3, in the case under consideration of a ship being hit by a breaking wave, an increase in the heel angle to values ​​exceeding 90° is observed, i.e. it can be assumed that . In this case, the angle of filling i.e. the condition is met , according to which it can be considered that the vessel has lost stability.

[0094] When monitoring the stability of a vessel, according to the closest analogue, the possibility of capsizing during the development of a rapid drift of a vessel from the impact of a breaking wave is determined from the condition

[0095]

[0096] where - restoring moment, kN⋅m;

[0097] - heeling moment acting on a vessel under the impact of a breaking wave and the resulting drift, kN m.

[0098] Heeling moment acting on a vessel in drift conditions after the impact of a breaking wave can be determined from the condition:

[0099]

[0100] where - applicates of the points of intersection of the line of action of the wave impact force and the drift resistance force with the centerline of the vessel, m;

[0101] - the applicate of the vessel's center of gravity, m. The corresponding dependencies for the vessel under consideration are presented in Fig. 1 and Fig. 2. Comparing the graphical dependencies presented in Fig. 1 and Fig. 2, it can be concluded that condition (10) is not satisfied. Thus, according to the closest analog, during the development of a vessel's rapid drift from the impact of a breaking wave, capsizing of the vessel is not observed.

[0102] It should be noted that in this case, the vessel's dynamic stability can be further assessed by comparing the magnitudes of the heeling and righting moments. However, this assessment also shows that the vessel does not lose stability when struck by a breaking wave.

[0103] However, as demonstrated above using the proposed method for monitoring vessel stability, the results of modeling the vessel's dynamics upon impact with a breaking wave, taking into account architectural features (Fig. 3), indicate that the vessel cannot withstand the impact of such a wave and capsizes. Thus, in this case, taking into account the vessel's architectural and structural features (the presence of a deck well and superstructures) leads to opposite conclusions in assessing stability than using a simplified approach based on the closest analog.

[0104] In this example, the vessel's stability under the impact of breaking waves with the predicted wave conditions cannot be considered satisfactory. Therefore, the navigator must avoid the area or take measures to improve the vessel's stability. The effectiveness of these measures can be assessed by simulating the vessel's behavior with the stability parameters obtained after their implementation.

[0105] Thus, the proposed method for monitoring vessel stability allows, based on actual wave measurements and weather forecast data, to predict vessel stability in breaking sea conditions. This allows the navigator, in the event of an unfavorable forecast, to decide whether to alter course or proactively implement measures to improve vessel stability, thereby enhancing navigational safety.

Claims

A method for monitoring the stability of a vessel in breaking waves, based on measuring the period of rolling and determining by calculation the metacentric height, in the calculation of which the draft of the vessel by the bow and stern, the "apparent" period of the wave, the course angle and the speed of the vessel in irregular waves are additionally measured, the angular velocity during rolling, the depth of water under the keel of the vessel and the parameters of the waves deformed in shallow water are additionally measured, on the basis of which the characteristics of the impact of breaking waves are calculated and the actual indicators of the dynamics of the interaction of the vessel with the external environment and the possibility of the vessel capsizing as a result of the impact of a breaking wave and under conditions of rapid drift from the impact of a breaking wave are determined, characterized in that the parameters of sea waves are predicted,determine the characteristics of the impact of breaking waves under predicted wave conditions and model the dynamics of the vessel when struck by a breaking wave taking into account the length and height of the superstructure and the presence of a deck well, after which they determine the greatest angle of heel as a result of the impact of the breaking wave and draw a conclusion about the stability of the vessel in the predicted breaking waves, and the loss of stability of the vessel is judged when the following condition is met:, Where - the greatest angle of heel as a result of the impact of a breaking wave, degrees; - the angle of flooding at which water floods the internal spaces of the vessel through openings considered open, or openings that may be open in the working condition of the vessel under operating conditions, in degrees.

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