At present, in practice, to model channel reformations in rivers with a deformable bottom, a large number of different formulas are used to calculate the flow of bottom sediments. However, the reliability of channel forecasts performed using the apparatus of mathematical modeling, in most cases, still remains quite low. The quality of channel forecasts performed when designing engineering measures to ensure navigation on rivers is determined, on the one hand, by the correct assessment of the physical nature of sediment transport in natural channel flows, and, on the other hand, by the quality of the applied numerical models. This work is devoted to the verification of the sediment transport model based on studies in hydraulic flumes, in which microforms and mesoforms of a river channel with a secondary type of channel process were simultaneously reproduced. Such problems have not been considered yet. The previous experiments were carried out with a uniform steady-state mode of water movement at one structural level of bottom sediment movement - with the movement of bottom sediments in the form of microforms (dunes) - i. e. on a flat day. The results obtained in the course of the research make it possible to obtain new data, using which it seems possible to improve the quality of modeling of sediment transport in natural channel flows. This line of research, based on the use of the methodology for calculating the discharge of channel sediments using the parameters of dunes, can objectively lead to an increase in the reliability of forecasts of channel reformations when keeping navigation on free and regulated rivers with a moving bottom.

Every year the need for automation of the most diverse spheres of human activity is growing. In various areas of industry, services, logistics systems, there is a global trend towards autonomy of production and transport processes. In the field of maritime navigation, the most promising solution for automation is the use of marine autonomous surface ships. A maritime autonomous surface vessel is a vessel that is capable of functioning to varying degrees without interaction with a human operator. The complete or at least partial absence of the crew on the route of the vessel significantly reduces the costs of transport companies. However, any operation of an object is always preceded by a thorough analysis of the area of use; therefore, the main criteria for the classification of unmanned vessels, which allow determining the main design features of the vessel, are presented in the paper. A large number of criteria for classifying a surface object according to various conditions creates certain problems with the selection of the unmanned vessel operation area, therefore, a method that takes into account all the proposed classifications, allowing to determine the area of operation of marine autonomous surface ships using the example of the waters of Peter the Great Bay, is proposed in the paper. The application of an automated approach to solving the problem of classifying an object using a specially developed software product makes it possible to increase the visibility of the method results and the convenience of its use. A software tool that requires the input criteria of the designed MANS for successful operation is proposed. The result of the work is a map, where the proposed vessel operation area is marked in color, and there is also a function for viewing information about the local environment for the use of a manned object. The interface of the software tool, as well as the results of its work on the example of the water area of Peter the Great Bay, are presented.

An analytical review of the current problems of practical use of the planetary magnetic field as a geophysical basis for navigation is provided in the paper. A hypothesis about the possibility of orientation by an individual signature of a certain geographical area has been put forward and it is based on the fact that the Earth has a measurable magnetic field in any place and at any time, which makes the contours of abnormal magnetic intensity a reliable source of navigation. The results of domestic and foreign studies on the identification of the experimental mean square error of magnetic positioning for determining coordinates with an index of 10 m are analyzed, which in the perspective creates a precedent for supplementing magnetic navigation with the reliable backup global positioning systems. It is noted that navigation by the variable mutability of the magnetic field demonstrates a high-precision positioning potential in GPS-denied environment. As a result, the point of view of the necessity to search for an alternative method is emphasized. The actuality of creating a duplicate system is motivated by the fact that the reliability of global positioning is the subject of attention when studying the issue of cybernetic awareness for the both marine and aviation applications. The innovative approach is considered in a broad aspect, taking into account the possibility of constructing an effective configuration of an artificial neural network to remove the local magnetic field of a ship or aircraft from the measuring data of a magnetometer when using a machine learning algorithm to ensure the reliability of autonomous navigation both in near-Earth space and indoors. A three-dimensional visual representation of a digital model of a simulated magnetic field based on basic finite splines is implemented in two comparative versions: an approximated perspective of magnetic anomalies and its stylized frame model with a mathematical justification of the feasibility of using different methods as optimal standards for mapping the informativeness of magnetic positioning. The planning horizon for the incorporation of spline technology into navigation information processing has been theoretically expanded to a strategy for using a gradient approach in synthesizing the heterogeneous structure of the geophysical field in order to effectively position mobile objects based on realistic consideration of the architecture of multifactor orientation of the gradient vectors spectrum.

The basis for ensuring the navigational safety of a ship is knowing the coordinates of its location at a given point in time. In modern conditions, the coordinates of the ship position in most cases are obtained using the global navigation satellite systems. However, there is a problem when using these systems, namely, failures in receiving navigation information from satellites. The causes of failures are interference to the radio signal of both natural origin and artificial (destructive) origin, caused by the interference of radio suppression equipment. A solution to the problem of detection of destructive interference in the radio channel of the satellite-receiver by using navigation on celestial bodies is proposed. The possibility of using navigation on celestial bodies in modern conditions implies efforts to improve this method and includes a set of measures. Among the set of measures, two directions are distinguished. The first direction is the improvement of the means for measuring the navigation parameters. The second direction is the improvement of the computing tools necessary for calculating the coordinates of the ship position, as well as solving navigational problems of ensuring navigation safety, namely, determining instrument corrections, providing time service on the ship, determining illumination and selection of luminaries for observation. The second direction of improving the navigation of the celestial bodies, namely, the identification of the trend in the development of computing means of navigation on the celestial bodies is considered in the paper. As a result of the work, the general trend of the global market which can be used to judge the growth and popularization of the maritime industry, is presented; the uneven development of the functionality of the presented programs is revealed; the advantages and disadvantages of this phenomenon are described. As confirmation of the growing relevance, reports of the international analytical organizations indicating the growth of the marine radio electronics market by 8.1 % per year until 2025 are cited.

The main international rules and conventions which set requirements to passage planning process are considered in the paper. A number of factors influencing the choice of ship safe speed in polar waters have been listed. Increasing a volume of merchant shipping in the Russian Arctic region is highlighted. Stable growth of maritime shipping along with development of new oil and gas projects require a detailed study of sea transport routes to ensure efficient export of mineral resources, including liquid hydrocarbons. It is observed that vessels quite often deviate from the recommended routes on the Northern Sea Route when ice conditions are prevailing. This causes the necessity of using optimization algorithms which would take into account variable ice conditions. The use of such algorithms should increase economical efficiency of Arctic merchant shipping. However, these algorithms should meet international regulations regarding safety of navigation and passage planning, ensuring safe navigation during the whole passage. It is underlined that use of optimization algorithm should be considered as one of the factors influencing safety of navigation therefore it should be included in the standard risk assessment prior commencement of the voyage. To ensure proper level of navigation safety, the safety management system onboard should be effective. This should include a number of amendments, which are listed in the paper for the situation when optimization tools are used operatively for passage planning. Mandatory risk assessment should take into account the use of such tools. A set of countermeasures, which involve ensuring the safe application of the optimization method, within the risk assessment procedure are presented in the paper.

The development of solutions to increase the throughput capacity of inland waterways through the effective management of the water supply system of the shipping lock chamber corresponds to the priorities of the development of inland water transport of the Russian Federation. The subject of research is the process of leveling the water levels in two communicating vessels. At the present stage of researches development, the solution of this problem is associated with an iterative procedure, the convergence of which essentially depends on the choice of the initial approximation and the step of numerical integration. The method of synthesis of the optimal control of changing the water level in the lock chamber is proposed in the paper (knowledge of an object as a single whole, in the unity and interconnection of its parts). At the same time, the solution of the problem of combined optimal control of a nonlinear system according to the hierarchy of functionals is considered. An idea of a self-organizing optimal controller with Krasovsky extrapolation is given. Particular attention is paid to control optimization at low computational costs in the process of system formation. The use of predictive models proposed in the paper makes it possible to obtain practical algorithms that do not require deep fundamental knowledge of control theory when they are introduced. The efficiency of the studied algorithms, when the process time changes, is shown. The presented solution makes it possible to carry out a comparative analysis of various methods of leveling water levels between the chamber of a shipping lock with a distribution power supply system and the corresponding pool, which allows solving one of the urgent problem of increasing the throughput of shipping locks in a section of the waterway with the unconditional fulfillment of ensuring safe locking conditions.

The problem of improving the quality of medium- and long-term forecasting of changes in the ice situation on the Northern Sea Route, and in particular in the East Siberian Sea, where one of the methods for choosing waterways is the passage of vessels in the areas of flaw polynya, is considered. The hypothesis that in the summer months such changes can be significantly affected by the terms of floods onset in the Kolyma River Delta is tested. The data of the GLORYS12v1 global reanalysis supported by the Copernicus Marine Service are used as factual material on the ice cover and levels of the East Siberian Sea in the months from May to October of 1993-2019. The reanalysis is based on mathematical models of the NEMO family, verified using altimetry data from satellite measurements. Using the developed methodology for the selected periods of the year, the dates of sharp changes in the level and ice cover on the pre-estuary seaside of the Kolyma River are estimated. Using statistical methods, the validity of the stated hypothesis for a number of the East Siberian Sea areas, along which the shipping lanes of the Northern Sea Route pass, is confirmed. It has been established that the greatest influence of the floods terms on the ice situation and navigation conditions in such areas takes place in July. It has been shown that early floods in the Kolyma delta generally lead to an improvement in the ice situation, and late floods lead to its complication. The identified relationships are recommended for use in forecasting changes in ice conditions. The assumption that with further climate warming and a shift in the flood terms to earlier dates, it is possible that the ice conditions will become more complicated due to the freezing of the formed polynya, is made.

The issues of the technological complex for manufacturing the hull of a small vessel obtained using additive manufacturing methods are considered in the paper. The purpose of the work is to study the emerging problems, issues, patterns, rules and norms of the process of 3D-printing the hull of a small vessel. The objectives of the paper include presentation of previously obtained calculated and experimental results for printing and assembling the ship hull; development of a method for assembling a hull using additive technology; comparative analysis of the labor intensity of manufacturing ship hulls using traditional and additive technologies; studying the issues of the slipway period of building the hull after completing printing work. The main methods for solving problems include well-known fundamentals in the technology of shipbuilding, ship repair, optimization of ships, technical and economic analysis, materials science, etc.; information about the production of marine equipment objects by additive manufacturing from filaments; the results of our own calculations and experiments for the production of a small vessel hull using additive technologies; well-known industry regulations and standards for working with fiberglass in shipbuilding. The technique of printing and assembling the hull of a small vessel, the necessary preliminary computational-analytical and experimental studies for redesigning the hull structure for additive manufacturing, the problems arising during and after printing and assembling the hull, and the analysis of the labor intensity of manufacturing the hull using additive and traditional technologies are considered. It has been found that not all types of small vessels will have advantages in terms of labor intensity in their additive manufacturing; it is possible to use incremental production. With the right organization of production management, additive technologies will have an advantage in terms of the laboriousness of the technological process in the production of hulls of kayak-type ships, and similar structures in terms of geometry and weight, with individual piece production.

The development of marine power engineering and automation, due to qualitative and quantitative changes by a significant increase in the capacity of modern power plants is considered in the paper. The object of this study is the flow part of a low-consumption inflow turbine, the subject of the study is the loss of kinetic energy in the stage of a low-consumption inflow turbine. The method of investigation is numerical simulation of gas flow using computational gas dynamics; the purpose of the study is to compare the values of kinetic energy loss coefficients in the nozzle diaphragm, impeller and output velocity losses obtained during physical and numerical experiments. The main objective of the study is to compare the values of kinetic energy loss coefficients in the turbine stage obtained during a physical experiment with the results of a numerical experiment. It is noted that low-consumption turbines are characterized by small dimensions, which do not allow to fully carrying out a physical experiment. A balance of losses of a low-consumption inflow turbine is performed in the study. A good convergence of the loss coefficients values obtained by the numerical method with the results of the physical experiment has been established. Conclusions about the possibility of applying numerical modeling for identical types of turbine stages are made.

One of the key problems that have developed today in the fleet during the operation of ships is the termination of supplying products from leading foreign manufacturers of dampers and antivibrators of torsional vibrations, which ensure the safe operation of critical elements of the engine complex. Also, the next confirmation of relevance is the fact that there are no maintenance service centers on the territory of the Russian Federation, nor specialists who carry out the defection and repair of such devices. The results of experimental studies to assess changes in the technical condition of the antivibrator, which is the driven part of the clutch disc of a well-known foreign manufacturer for a KAMAZ truck, at the laboratory stand of the Marine Technology Service testing center of the Astrakhan State Technical University, are presented in the paper. The purpose of the tests is to evaluate the changes in vibration and torsional vibrations occurring in the elements of the laboratory stand at different states of the damping springs of the antivibrator. It should be noted that this device is used on YAMZ-236 engines, which is convertible on the ship. The change in the technical condition of the antivibrator is ensured by a complete limitation of the stroke (jamming) of the damping springs. Mechanical jamming is performed sequentially for each spring package and by measuring tangential stresses in the shaft of the laboratory stand and vibration acceleration on the bearing assembly rack. To conduct the experiments, the measuring base of the test center, including a torsional vibration monitoring system, a 1st class vibrometer, an Ecophysics-110 spectrum analyzer, etc., is used. It has been experimentally established that when the free travel of the damping springs of the anti-vibrator is completely limited, tangential stresses in the shaft and vibrations on the bearing assembly of the laboratory stand increase. It is also determined that the average tangential stresses in the shaft are more effective in terms of the criterion for diagnosing the antivibrator technical condition than the maximum stresses. The most informative for antivibration diagnostics are the octave frequencies of 4, 63 and 125 Hz, at which there is a significant change in vibration acceleration along all three axes X, Y, Z, depending on the number of jammed springs. The accumulation of theoretical and practical research in this area, in the future, may lead to the development of a methodology for the non-selective assessment of the technical condition of ship mechanical dampers and antivibrators of torsional vibrations.

In recent years, a real opportunity to create a capacitive-storage energy source based on supercapacitors with increased energy intensity has appeared. At present, on the basis of supercapacitors, an energy storage device (ES) has been created, and there is an experimental process, the power of which in the model of an electric power system is 10 kW. The level of stored energy is determined by the type of storage device (30 kJ or more). The purpose of the paper is to develop effective methods for increasing frequency, rotor angle based on modern energy storage devices (supercapacitors). The program of Power System Simulation for Engineering (PSS/E) is used in the study. The importance of the work is described in the paper and the features of the impact of using supercapacitors on the stability of frequency and rotor angle by making several experiments with different capacities and voltages and then comparing the results obtained using the PSS/E program are considered. Ensuring the stability of the load schedule at the maximum consumption of electricity in the electric power system of a certain region or country is a long-term procedure that needs to be developed and improved in the means of its implementation. Modern systems have characteristic features, such as an increase in the unevenness of load schedules, the need to generate power from generation facilities in each period of time, an increase in the steepness of load schedules, scaling of power plant equipment, which increase their economic feasibility of operation, reduce their maneuverability, etc. Search and development of new ways and methods for compensating peak loads in the electric power system are relevant and in demand.

The operational task of automating the construction and routing of the network model with the known coordinates of the conditional goals set for a group of vessels to achieve them in the minimum time is solved; it makes it possible to obtain the reserves of running time necessary for saving fuel and energy, taking into account the load, the cost of cargo, transportation costs, logistics characteristics, etc. It is emphasized that in stormy weather conditions and vessel management in situations related to schedule correction, flexible operational decisions of dispatching services, made on the basis of numerical optimization methods using modern computing environments, are necessary. In this regard, the method of dynamic programming, implemented using the Bellman-Ford routing algorithm, which is supplemented by a recursive step-by-step optimization procedure that removes the limitation of the algorithm in the presence of inversely oriented edges with negative weights in the graph, is discussed in the paper. In the presence of negative weights, there are conditions for the appearance of a negative cycle in the graph, in which the practical implementation of the Bellman-Ford algorithm will become impossible due to an endless cycle of relaxations (attenuation) of the vertices weights included in this cycle. Hence, at a limited period of time for weighing all vertices (passes on all edges), the algorithm can give a knowingly false result. The proposed procedure for modifying the well-known Bellman-Ford algorithm eliminates this limitation and allows it to be used not only for estimating the shortest paths in a network containing arcs with negative weights, but also to detect negative cycles in it. The modified Bellman-Ford algorithm is implemented as a program compiled in MATLAB codes, and it is demonstrated by the example of automated construction and calculation of a network model containing both positive and negative edges (flows), using a recursive procedure of step-by-step optimization. It is shown that the proposed model, unlike the known models, eliminates the limitations caused by the presence of negative cycles in the network model, which makes it possible to automate the search for the shortest paths to conditional goals by the functional means of the MATLAB environment. The constructed computer model is simple and compact. The proposed algorithm and the recursive procedure are recommended for finding energy-efficient solutions for managing mobile objects in water transport.

The electric cylinder as a promising type of electromechanical drive for controlling the main miter gates is analyzed based on domestic and foreign experience. It is shown that, for a number of reasons, several different types of electric drives are in operation in Russia, differing from each other in kinematic schemes, operating parameters, dimensions and operational costs. Variety of electric drives types reduces their serviceability, requires the search for spare elements, the performance of repair work by third-party organizations, which, in turn, reduces the productivity of the gateway process. The operated electromechanical and electrohydraulic inputs of the main double-leaf miter gates of navigable locks with a chamber width of about 18 meters are analyzed. It is shown that the results of the drives comparison make it possible to clarify the calculations of the required power and load capacity, to contribute the development of a single regulatory document regulating the process of designing and selecting the operating parameters of an electric cylinder for specific operating conditions. The data compiled on the basis of foreign and domestic experience in the operation of different types of double-leaf miter gate drives, trends in their development, the reasons for their replacement with more modern drives are obtained. Special attention is paid to the disclosure of the reasons for replacing standard drives with an electric cylinder during the locks reconstruction. It is shown that the accurate calculation of the actually required performance indicators and the correct choice of the electric drive type, based on the conditions of future operation, lead to a noticeable increase in the life cycle of the shipping lock and its mechanisms.