The sea transportation system, which in turn forms the basis of the global trade system, has been developing during the whole history of human civilization. The abrupt leaps in this steady development were caused both by the changes of technological paradigms (e. g. by the shift from sail to steam, appearance of steel framing and hull shells, containerization, digitalization etc.) and social reasons (abandon of the acceptable losses strategy after world wars, end of cold war, relaxation of the international tension and war conflicts etc.). Unfortunately, the social factors can not only push forward the development, but also have destructive character, manifesting themselves as crises of different scales and natures. The complexity and the scope of the global transportation system that has developed by the XXI century have already shown the tendency to kaleidoscopic changing of its states under small shocks. In full scale this sensitivity has developed after COVID-19 and Ukraine affairs. It seems unreal to expect not only quick revival of the collapsed world system of sea and land transportation, but even preservation of its structure. Consequently, the key elements of the transport infrastructure, i. e. sea port, found themselves in a very serious situation. Major ports have faced a problem of cargo flows deterioration and relevant redundancy of their capacity; minor ports have discovered the opposite problem, namely, the residual cargo flows squeezed on the periphery of business areal turned out to be too large for the existing facilities and resources. In both cases the changes in external commercial environment and relevant route patterns set for the ports a task of finding a new balance between potential cargo flows and existing resources. A decision of this problem by the methods of mixed integer linear programming is described in the paper.

In order to analyze the effectiveness of interaction of the cargo terminal operator with customs authorities and participants in foreign economic activity, a four-sector model of the network diagram of the interaction stages between participants in the transport and logistics process at the sea cargo terminal is presented in the paper; the model allows visualizing and controlling the process of aggregated relationships during cargo operations and the provision of customs services in the area of seaports activity. Calculations of works time parameters are performed on the basis of a four-sector model, in which the event is divided into four sectors, where the number of the event is indicated on the top, the early start of work is indicated on the left, the late end of work is marked in the right sector, and the number of the initial event of the previous work is indicated in the lower sector, according to which the critical path passes. At the same time, simulation modeling of the system of relations between the participants in the transport and logistics process at the sea cargo terminal is carried out. When modeling by the Monte Carlo method, a set of parametric values presented in the form of a probability distribution is used. It is noted that the operations performed in the simulation are subject to the normal distribution law, since a large number of participants are involved in the transport and logistics system. The results of the algorithm operation are presented in the form of a data array, which is a sequence of works performed during the interaction of participants in the transport and logistics process at the sea cargo terminal. One of the methods for modeling randomly distributed variables is the Box-Muller generation method. The use of the Box-Muller method in the work makes it possible to apply the fundamental law of probability transformation to obtain two independent normal variables that have a standard normal distribution. Thus, the chosen method gives a set of random numbers that have a normal distribution with zero mean and unit standard deviation. The results of simulation modeling allow us to conclude that the aggregated system of relationship between participants in the transport and logistics process, which uses the technology of preliminary declaration in order to make a decision on the early placement of goods in the inspection zone, is effective.

The issues of cybernetic security are considered in the aspect of effective proposals of alternatives to the satellite system in order to be able to promptly reorient to a backup positioning system in case of any technical problems. The assessment of the use of computer-specific competencies in the field of information technologies of the marine fleet as a secondary factor of end-to-end cybernetic security management is given. Information processing in a duplicate analogue of the positioning system is based on the technology of spline functions in order to extract the advantages of piecewise approximation for practical navigation purposes. The functionality of the navigator is analyzed within the framework of the «augmented reality technology» of the bridge of the future with the possibility of observational fixation of the look of the watch officer based on improved virtual professional scenarios against the background of the flow of typical navigation information. In addition to alternatives to the traditional positioning system, the requirements of space all-weather, system noise immunity and round-the-clock use in emergency situations, military conflicts and man-made disasters are formulated. In the circumstances of uncertainty of satellite systems, the problems of their vulnerability are theoretically leveled due to the intended use of navigation equipment based on other physical principles of operation. Correlation-extreme navigation through natural geophysical fields, the innovative e-LORAN project and the means of celestial navigation automated on the basis of computing resources of the onboard computer are highlighted as promising variants of the autonomous positioning principle. The research carried out in this work is combined with the results of experiments within the framework of the magnetic navigation project on the practical implementation of autonomous aviation positioning. Validation of the characteristics of the isotropic field as an informative standard of correlation-extreme navigation is confirmed by practical implementations of various fragments of geophysical fields in the form of three-dimensional visualizations of spline synthesis. The accuracy of geolocation with «terrain-referenced navigation» by extreme indicators is analysed. The forecast of achievability of the predictability effect of a mobile object location in a satellite-based environment is given with optimal motion control using predictive modeling, provided that an accurate assessment of the uncertainty of the navigation system is foreseen. The algorithms tested on the methods of spline functions to ensure authoritative positioning are performed as an intellectual support for the ship’s management staff in an emergency situation.

The technology of purification and disinfection of ballast water developed by the authors is presented in the paper. Based on the results of a systematic analysis of the problem and on research experience in this field, it has been shown that the quality of ballast water discharged overboard after its use as ballast is determined by such basic factors as purification technology and design features of treatment devices, as well as conditions for operations with ballast water. The technology of ballast water purification as a complex of operations for purification, treatment and disinfection is determined by environmental requirements for the quality of purified and discharged overboard water, as well as the properties of the initial ballast water. The analysis of modern environmental requirements for the discharge of ballast water is given. It is shown that these requirements establish the level of permissible bacteriological danger of the discharged ballast water, taking into account the dispersed characteristics of the bacteriologically dangerous substance. These requirements determine the composition of operations that should be included in the technology of purification and disinfection of ballast water. Based on the results of the analysis of environmental requirements for the quality of purified ballast water, which determine the required water quality, a number of technological solutions collectively representing the technology of water purification and disinfection are proposed and justified. As disinfection, the use of ozone as an effective oxidizer is proposed. The use of sedimentation is proposed to regulate the content of dispersed particles of pollutants. Technological solutions also take into account the need for operations with a large amount of ballast water, as well as high reception and discharge capacity. It is proposed to carry out the disinfection process in small volumes of sediment, which is a concentrated mass of bacteriological substance obtained during preliminary coagulation and sedimentation, for which ship ballast tanks can be used. The proposed technology can be applied both in ship installations and in offshore environmental protection equipment - floating or coastal, for example, port facilities.

One of the important tasks of environment conservation, such as reduction of greenhouse gas emissions by commercial fleet, which is under special consideration of the International Maritime Organization (IMO) and becoming a basis of world trade policy, is considered in the paper. The analysis of the container transportation system in world trade demonstrates its growing role. The dynamics and trends of the modern container fleet for the period of 2015-2020 confirm the thesis of the growing importance of the container system in world trade. The volumes of greenhouse gas emissions and contributions by the tanker, bulk carrier and container segments of the world merchant fleet are considered, the conclusion about the low environmental efficiency of the container fleet toward the volume of cargo flow is presented. Options and consequences of including the Northern Sea Route in the global logistics network to reduce greenhouse gas emissions are proposed. Based on early studies, the comparative calculations linking variation of ship speed with reduction of carbon dioxide emissions for four types of container ships on the routes including the Northern Sea Route and through the Suez Canal are given. Estimates for the mentioned reduction due to shortening the route between Europe and Asia are proposed. The practical applicability of the calculated estimates and their impact on the overall environmental friendliness of transport corridors in the case of more active use of the Northern Sea Route as a transit route for the goods flow from the Asia- Pacific region is discussed.

The impact of surface currents on variations in levels and mean ice thickness of the Arctic seas is considered in the paper. On the example of sites of the Greenland Sea and the Baffin Sea water areas, the hypothesis of a significant correlation between changes in the topography of the water surface and the average ice thickness in areas under the influence of warm and cold surface currents is tested. Similar, although less expressed, patterns of currents also take place in other Arctic seas, including the Barents and Kara seas, which are characterized by intensive navigation in the waters of the Northern Sea Route. The results of the GLORYS12v1 reanalysis, available for every day of a period of more than 10 years with a coordinate step of 5 arc minutes, are used as initial data on the water surface level and mean ice thickness in the study area. For each node of the coordinate grid for the months from November to March, time series of data on the average monthly values of the indicated characteristics are formed. It has been established that at the sites through which warm currents pass, carrying more saline water, such a correlation exists in most areas and it is negative. At the sites through which cold currents pass, carrying water with lower salinity, the correlation of the same processes can be significant and positive. It is assumed that the identified patterns are also manifested in other areas of the Arctic seas with similar currents systems, including those located along the Northern Sea Route and characterized by active navigation. The expediency of taking into account sea level changes in such areas in the course of medium- and long-term forecasting of the average ice thickness in them in order to plan year-round navigation, including during the most difficult winter-spring navigation period, is noted.

The possibility of using the areas of flaw polynyas in the Eastern sector of the Northern Sea Route in planning and choosing the routes for navigation of transport ships is considered in the paper. It is noted that shipping in the Arctic seas is associated with an increased level of risk, shallow seas and difficult hydrometeorological conditions, and is also characterized by insufficient or completely absent hydrographic knowledge of the bottom topography. The main data characterizing the increase in the number of issued permits for ships navigation in the water area of the Northern Sea Route, and the percentage of ships depending on the ice class are given. It is noted that in the cold season, the main navigable straits of the Northern Sea Route are covered with fast ice. Due to circulation and under-ice currents, flaw polynyas, which can be used when planning navigation routes, are formed. The main flaw polynyas of the Eastern Sector of the Northern Sea Route are presented; data on their width, length and range of depths are provided. It is noted that the flaw polynyas of the East Siberian and Chukchi seas are deeper than the polynyas of the Laptev Sea. The ships classification depending on the draft is presented in the paper; an analysis of the characteristic routes for each category of ships is performed. An analysis of the data received from the automatic identification system of vessels has revealed that the choice of route is seasonal and directly depends on the ice conditions of the water area. The relevance of the topic is due to the need to increase the duration of navigation in the Eastern sector of the Northern Sea Route, in order to achieve targets for the volume of cargo transportation. This can be achieved by choosing the route of the transport vessel along the areas of ice polynyas, which are a strip of open water and young ice.

The changes in the bearing capacity of the hull sheets and beams of the ship’s set under the action of compressive and tensile forces are studied in the paper. The inf luence of local residual deformations on the permissible wear of the deformed element, which allows assessing its reliability, is established. Since the longitudinal forces (compressive and tensile) are significant only for the deck or bottom in the middle part of the hull, the effect of local residual deformations on the bearing capacity of sheets and beams of the longitudinal set is estimated only for these elements. It is assumed that the retained local residual deformations of the housing elements do not change with the time of ship operation. Corrections for permissible wear in the cross-section equal to a decrease in the average thickness of the sheets in the cross-section are calculated (for a section of the body equal to the length of the sheet, from joint to joint). The wear rate of all cross-section sheets is assumed to be the same, and the probability of its occurrence corresponds to the law of normal distribution with the characteristics specified in the Rules of the Russian River Register established for a given group of elements. According to the assumptions made above, it is possible to calculate the probability of failure in the cross-section of a group of elements with local residual deformations depending on the number of years of the vessel operation. The probability of failures in a given group of elements is estimated by the multiplication of the failures probability in several sections after a given number of years of operation. The probability of failures in the hull of the vessel is calculated as the multiplication of the failures probabilities in all groups of elements. Formulas for calculating the loss of the bearing area of the sheathing plates and beams of the longitudinal set due to the local residual deformations have been obtained. The loss of the working area of the sheets and longitudinal beams is represented as additional wear of the sheets. After dividing the mentioned loss of the cross-section area by the cross-section width, the value of the permissible reduction in the residual thickness of the sheets, weighted average for the section under consideration, is obtained.

The most common case of deformation of frame T-beams is taken as the object of research on the accuracy of modeling the geometric parameters of the cross-section of the deformed nodes of ship hull structures. The exact, determining the strength characteristics, geometric parameters of the cross-section of a deformed wall of a frame beam and a beam with an attached sheathing belt in a deformed wall with several models replacing the original section in succession, are compared in the paper. The scanned cross-sections of beams models with a deformed wall are taken as the evaluated objects. The models have several options for the ratio of the wall height to its thickness and different forms of buckling of the beam wall. Based on the simulation results, a comparative assessment of the values of these parameters is given and a conclusion about the accuracy of the simulation results sufficient for practice is made. In addition, it is shown that the modeling accuracy allows satisfactorily assessing the geometric parameters of the strength of the cross-section of the frame beams of the ship’s set with a deformed wall without direct access to the beam and assessing the zone and type of wall deformation - by measuring the deformation of the outer side of the skin at the attachment point of the beam. A composite model, representing a set of an undeformed T-beam with a wall of the same thickness, height equal to the height of the deformed beam wall and a sheet element in the plane of the beam wall adjacent to the skin, is recommended as the main one. The height of this element is 2/3 of the height of an undeformed beam with a cross-sectional area equal to the difference between the wall areas of the undeformable modeled and imitated beams. In addition, the accuracy assessment of determining the geometric parameters of the strength of the cross-section of a T-beam with an attached sheathing belt in the case of a deformed wall and its reinforcement with sheet elements in the plane of the wall is given. It is concluded that the use of this modeling method allows one to obtain models convenient for the analytical description with their satisfactory accuracy.

An overview of using pneumatic pressurization systems of icebreaker hulls in order to increase their icebreaking capability and a description of traditional design solutions in the design of systems are presented in the paper. It is noted that the design of systems is based on the methods of analogy and similarity, taking into account the results of field tests. Theoretical methods of taking into account the design features of the icebreaker hull and the technical characteristics of its power plant when determining the required air supply, its parameters, and outlets location are currently insufficiently developed. It is shown that the improvement of anti-icing devices of icebreakers provides an increase in their energy efficiency. The main areas of pneumatic charging devices improvement is to reduce the cost of driving supercharging units and the possibility of using secondary energy resources of marine diesel engines for their drive. The calculations results of the power required for the drive of air blowers depending on the air supply, other factors determining the energy consumption of the air blower system are indicated. The results of the conducted research confirm the possibilities of improving the anti-icing devices of icebreakers in order to increase their energy efficiency. The proposed method makes it possible to determine the required power costs and assess the possibilities of covering them with secondary energy resources with improved air blower drives. The maximum increase in energy efficiency can be achieved by choosing rational air supply parameters, reasonable placement of air supply openings, taking into account the design features of the icebreaker hull and the use of secondary energy resources of the main and auxiliary elements of the icebreaker power plant.

The main breakdowns that may occur during the operation of the deck equipment of a fishing vessel are presented in the paper. These breakdowns can lead to devices failure, serious accidents, which, in turn, entail a decrease in the operational and economic efficiency of the ship’s auxiliary power plant and the ship as a whole. Therefore, in order to improve the maintenance system of deck equipment, it is necessary to improve the methodology for predicting reliability based on structural indicators of elements at the design stage. One of the methods for solving the task is to obtain, accumulate and statistically summarize information on the operational reliability of units, parts and equipment as a whole. For risk analysis during the operation of ship equipment, at the first stage, a classification of hazards based on available data and existing developments of technical means is required. To estimate the average resource and other indicators of the durability of ship mechanisms, it is necessary to know the parameters of the random factors distribution. This will allow, under different laws of parameters distribution, to predict the resource distribution by statistical modeling. The assessment results of the failures of the deck lifting equipment of a fishing vessel are considered in the paper. It is revealed that mooring, anchor and trawl winches, for which operating time data are given, are subject to the greatest failures. The probability of no-failure operation of parts is calculated and its graphical distribution is presented. The results obtained in this work contribute to the further continuation of research in the field of ensuring the required level of performance of elements of deck mechanisms.

The subject of this study is internal combustion engines capable of using gaseous fuels-gas and dual-fuel engines. The main technologies of using natural gas in piston engines from the standpoint of ensuring the highest energy efficiency and environmental safety are considered in the paper. It is noted that the use of natural gas as a fuel, regardless of the technology, reduces carbon dioxide emissions from combustion products by 28 % compared to liquid fuels. All known designs of gas and dual-fuel engines fundamentally implement two technologies, namely, the use of homogeneous or heterogeneous gas-air mixtures. The most common is the technology of homogeneous mixtures, which provides high fuel efficiency and the highest environmental safety indicators. This technology provides for the supply of low-pressure gas to the intake ducts of the engine through automatic gas valves. There are practically no sulfur oxides, solid particles in the exhaust gases of the engine, and the emission of nitrogen oxides can be provided at the level of the requirements of the Tier III standard. At the same time, the main disadvantage of the homogeneous mixture technology is the potential penetration of natural gas with a high level of greenhouse effect (which is up to 28 times higher than the effect of carbon-acid gas) into the exhaust tract of the engine - “methane slippage”. This negative aspect can be largely minimized through the use of heterogeneous technology, when fuel gas is fed directly into the cylinder of a dual-fuel engine under high pressure, up to 50 bar, at the end of the compression process. This technology is becoming widespread in the structures of two-stroke engines due to the specifics of their gas exchange process. However, the high dynamics of the heat release process in the implementation of heterogeneous technology of gas-air mixtures is associated with a high emission of nitrogen oxides, commensurate with the emission of NOx by a diesel engine. Based on the analysis of the parameters and characteristics of the products of leading manufacturers implementing various technologies for using natural gas as fuel, conclusions about the potential advantages and prospects of using gas and dual-fuel engines are made.

The process of pulse width modulation (PWM) in the converter - electric motor system is considered. It is noted that the main task of pulse-width modulation of the voltage generated by the electron-key converter in the converter - electric motor system is to reduce current pulsations during the modulation period. It is proved that the dynamic process of changing the current in an electric machine on the PWM period can be approximated by an R, L-filter. It is established that the most important task of PWM is to minimize the current modulation error in the electric motor. The analysis of possible criteria for assessing the quality of the modulation process in electric drive control systems is carried out. It is shown that as an optimality criterion for assessing the quality of modulation in a converter - electric motor system, it is advisable to use an integral quadratic criterion of relative error, called local current dispersion, as well as the average value of local current dispersion over the period of the modulating function, called integral current dispersion. The process of single-phase modulation on a single-phase load is considered. Analytical estimates of the load current dispersion for this process are obtained. A condition, under which the current dispersion takes a minimum value, is recorded. The efficiency of pulse-width modulation optimization by the criterion of current dispersion is investigated. The average dispersion of currents in the load with a centrally symmetric arrangement of pulses on the modulation interval is taken as the base value of the dispersion. An expression that allows us to evaluate the efficiency of optimizing the current dispersion, taking into account the increment of the center of the modulation interval, is obtained. The dependence illustrating the efficiency of optimization by the criterion of pulse displacement relative to the center of the PWM interval on the relative frequency of modulation at different amplitudes of the modulating voltage is constructed. An expression is obtained for estimating the average value of the local current dispersion over the half-period of the modulating function.

The issue of power system voltage stability, which is one of the key issues in the process of planning and operation of the power system, is considered in the paper. It is noted that neural networks have now been tested in a number of technological incidents in the form of power system voltage instability in various countries. The problem of possible risk of voltage failure due to the loss of its stability in the energy system during its operation is investigated. It is noted that in this regard, conducting a voltage stability analysis is an important procedure in order to timely identify buses with low reliability within the power system. Thus, the control personnel of the power system should take certain measures to avoid any cases of voltage drop within the system. The purpose of this paper is to present a new method for estimating the voltage stability load index (L-index) for a power system using data from optimally placed phasor units (PMUs). The voltage stability load index is evaluated in the work using a recurrent neural network known as the echo state network (ESN). The PMU optimal placement is made taking into account the island operating conditions. The results of the PMUs optimal placement for normal and boundary operating conditions, as well as the evaluation of the L-index using ESN in the IEEE 14 bus system, are presented. A technique for estimating the voltage stability load index in a power system based on a network of echo states using PMU measurements is presented. An estimate of the ESN performance for the L-index has been performed; the results have shown a high accuracy of its estimate under normal and disturbed conditions. It has been proven that ESN development is efficient and provides an accurate evaluation in computations.