One of the tasks of managing the work of the fleet of a small shipping company engaged in the transportation of supply cargo in the Eastern Arctic regions at the level of voyage planning, namely, the private task of arranging auxiliary watercraft for unloading transport vessels on the raid, is considered in the paper. It is noted that the production necessity for frequent adjustments to the voyage plans of small companies leads to the repeated solution of the same production planning task, but with different input parameters. It is the iterative nature of the management decision-making process that primarily justifies the relevance of solving the problem of voyage planning automation. It is shown that the main problem in automating the process of managing the work of a group of vessels is the development of mathematical models that are adequate to the real processes and economic conditions on the market, using numerical optimization methods. In the course of the scientific research, the adaptation of the classical model of production planning to the technological parameters of the task of organizing the processing of ships on the raid with the use of the port fleet for unloading is carried out. The main results of the study are the following: a model of the placement of the auxiliary fleet in conditions of its shortage, performed by linear programming methods, with its implementation in the environment of application programs of the MATLAB package, as well as a numerical experiment to substantiate the reliability of the obtained model solutions and prove the adequacy of the proposed model of the fleet placement to the real technological process. A distinctive feature of the mathematical model in the form of a software product is the flexibility of reconfiguring input parameters to changing conditions and tasks performed, due to the organization of their input in file of text formats. The practical application of the mathematical model “Placement of the auxiliary fleet” and its analogue of the subprogram within the automation of the management process of a group of vessels in small segments of the sea transportation market allows us to evaluate the efficiency of the port fleet and form optimal schemes for its placement for the nearest navigation.

The issues of implementation of long-term goals of sustainable development of sea passenger transportation, achievement of transportation results, overcoming the negative impact of factors of unstable external environment, which are determined by the chosen course laid down in the basis of strategic management of ferry transportation and choice of route directions, are investigated in the paper. The study indicates that despite the negative impact of COVID-19 and the resulting delayed passenger demand for cruise services, the potential of the maritime ferry and cruise market is very high. It is noted that since 2021 there is a gradual process of recovery of route networks, which takes place in different regions with different dynamics. Therefore, the goals of ferry companies are to implement several strategic planning tasks, among which the task of designing the most efficient new route network is relevant, while companies can start to implement route networks and destinations based on the existing route networks (e. g. networks and destinations of the Baltic Sea) for 2019. It is emphasized that due to the new possibility to attract additional passenger traffic, detailed research and modelling of different options is needed. The Baltic Sea region is chosen as the object for the study, since the local mobility of passageways makes it possible to renew the routes in the shortest possible time. The data for different seas, characterizing the intervals of decline and justifying the necessity of innovations on the basis of new competitive routes creation, are presented in the study. The subject of the study is routes and route networks of the seas regions. The use of models in the form of graphs and algorithms, such as Dijkstra’s algorithm, is proposed for modelling different variants of sea ferry routes architecture. The new ferry route network model is implemented in the J-Circos software environment for the subsequent construction of various intensity diagram options. Due to the flexibility of the interfaces and the software environment it is possible to combine the existing networks in 2019 and the proposed new routes in a single information field. In this way, a new possibility to assess the position of a ferry company on the passenger market and to evaluate the quantitative indicators in relation to the other ferry and cruise companies is considered in the paper. The proposed solutions are included in a separate decision-making flowchart for selecting a promotion strategy in the sea region ferry market. The solutions presented have versatility, the methodology and implementation can also be applied to the other sea regions. A new possibility of representing evolutionary changes in the route networks, which also provides an opportunity to further improve the quality of strategic planning and promotion decision-making, forming a separate area of analytical work of a maritime ferry company, is considered.

The growth of trade and sea freight flows in the Asia-Pacific region determines the possibilities for Russia to effectively enter the new Asian markets of trade, sea transportation, shipping services, etc. These and other factors create the opportunities and needs in the development of shipping and shipbuilding in the Far East associated with maritime activities in general and related services. The retrospective forecasting methods of fleet development are analyzed in the paper. A methodological approach to forecasting the demand in fleet assets to carry the common types of cargo in present-day conditions is proposed. The estimation is based on forecasting the cargo base, segmentation of the shipping market, analysis of the state of the existing fleet with prospects for ship decommissioning, assessment of the state-owned fleet demand, service, auxiliary and other fleet assets. Special attention should be paid to the regional shipping specifics and the formation of demand for cargo tonnage. This approach can be used in the formation of strategies of different levels in the field of shipping, shipbuilding and transport development, as well as for planning process by shipping companies. To demonstrate the application of proposed methodology, the calculation of the need in fleet assets to transport crude oil to the countries of East Asia was made for the Far Eastern Basin, based on the forecast of the cargo base in the segment of crude oil transportation. The calculated data is preliminary; it requires further clarification of possible parameters deviation in accordance with the expectations for the development of cargo flows, the needs for the development of maritime activities in the basin, the possibilities of optimizing the types of vessels and their modes of operation.

The reality of the navigator’s daily work with typographically published nautical charts focused on numerous reference ellipsoids is taken into account in the paper. The obligatory condition for the transformation of coordinates obtained using the data of the global satellite navigation system based on the Earth-wide coordinate system into the coordinates of the reference ellipsoid of the marine navigation chart is accentuated. Attention is drawn to the probability of a precedent of making a calculation error by a navigator with a standard recalculation of coordinates. Specific examples of discrepancies in the geographical coordinates of the same point on the Earth’s surface attributed to different geodetic systems are given. The facts of the multiplicity of reference ellipsoids reserved in the memory of electronic devices for satellite positioning of the vessel are emphasized. The review of the coherence problems of geodetic coordinate systems for the correction of fixing position is carried out. The hypothesis of a cardinal solution to the problem of positioning a vessel on an electronic or paper chart when reorienting navigation to a spline geoid model with the condition of repurposing cartography on a new mathematical basis is put forward. The assumption about the real possibility of freeing the watch officer from the routine procedures of mathematical transformation of coordinates for various geodetic systems when using the spline model of the geoid as a single cartographic basis is made. As a proof of the efficiency of the proposed approach, a spline synthesis of a fragment of a three-dimensional perspective of the geoid isosurface of the Indian Ocean with local identification of the phenomenon of anomalous gravity loss is implemented. In parallel, the computing service of the Helmholtz Potsdam Research Center for Global Earth Models was used to chart the gravitational anomaly of the Indian Ocean and computer reconstruction of the pear-shaped geoid in 3D format. A comparative analysis is performed and the disadvantages of the traditional algorithm for approximating an equipotential surface based on the spherical harmonics method are revealed. It is argued for the multiple use of the developed approach in the long term when approximating a planetary equipotential shape with pulsating dynamics. A prediction for the principal possibility of achieving absolute navigation accuracy in the case of using a single spline geoid model in modern navigation is given.

The phenomenon of vibration is considered in the paper. A serious threat to the safety of stationary marine structures operating in conditions of ice fields drift, is the vibration that occurs during cutting of the ice cover by the supports of structures. The process of interaction, as an object of research, is described by the force of resistance to a change in equilibrium in the formed natural-man-made “ice field - structure” system, simultaneously affecting both the edge of the ice field and the base of the structure, and growing to a certain maximum, then “dumped” to a certain minimum. The moment of the beginning of ice destruction is due to the achievement of the critical density of elastic energy accumulated in the compressed local volume of ice in the contact zone, which is the trigger of ice load phenomenon release on the structure and the beginning of its return to the equilibrium state, i. e. is the source of its oscillations. Such cyclic destruction of ice, as the main subprocess in the complex process of interaction between the ice field and the structure, must be viewed as a subject of research, since this phenomenon reflects the real mechanism of transforming the kinetic energy of the ice field movement into the potential specific energy of the newly formed surfaces of the destroyed fragments of ice. As a methodological basis and a tool of scientific research, the system analysis is used in the work as a method of setting and solving the problem through the decomposition of the process under study, analysis of its constituent phenomena and synthesis of an adequate model of cyclic ice destruction to study unsolved problems in calculating the loads of ice fields on offshore free-standing structures. The characteristics of the cyclic process of ice destruction, both the values of ice load peaks and their frequency are the initial parameters when performing a dynamic calculation of the structure to determine its reliability level. Obtaining these characteristics is possible only when using the energy criterion of ice destruction, the type and location in the design system of which are defined in the work.

The results of the current level of development of data transmission technology using underwater acoustic modems are presented in the paper. Underwater acoustic modems are widely used in the communication networks of underwater robotic vehicles. Such systems are designed to solve various problems in the study and monitoring of sea areas. The specificity of data transmission in an underwater acoustic channel is considered. The effects arising from the low speed of sound propagation in the underwater environment are described. Possibility of distortion due to multipath propagation and the Doppler Effect is indicated. An overview of existing underwater acoustic modems is presented. The main characteristics of underwater acoustic modems, such as bandwidth, range, data rate, modulation type, etc., are highlighted. The most important parameters that determine the tactical and technical characteristics of the modems are range and data rate. The empirical dependence of the data rate on the distance is revealed. The current maximum data rate in the underwater acoustic channel is given. The data given by the modem manufacturers correspond to the case of an ideal channel. The best manufacturers of the underwater acoustic modems are indicated. The features of the most common types of modulation are considered. Modulation using Sweep Spread Carrier technology is described in detail. This modulation allows you to compensate for the effect of multipath propagation and take into account the Doppler shift due to the motion subscribers of the underwater acoustic network. Spectrum spreading technology is considered. The applying of modulation using spread-spectrum technology improves the noise immunity of underwater acoustic modems. The need to formalize the calculation of the signal-to-noise ratio for the hydro acoustic data transmission channel is emphasized. The prospects for the development of data transmission technology using underwater acoustic modems are determined.

The economic performance of ship power plants is directly dependent on fuel consumption. Consumption is determined by the completeness of fuel combustion, which is influenced by many factors, one of which is the component composition. High molecular weight compounds, resins and asphaltenes contained in marine fuels are poorly flammable. They also form a coarse dispersed phase in the fuel, which complicates the process of hydrocarbon oxidation and leads to a decrease in its efficiency. It is known that ultrasonic influences increase the degree of fuels dispersion. The purpose of the work is to identify the regularities of ultrasound effect on the physicochemical indicators of distillate marine fuel of the DMA brand, which determine its operational properties: flammability, combustibility and pumpability. Experimental studies on the processing of marine fuel are carried out on ultrasonic devices LUK-0.125/50-O and Volna UZTA-0.4/22- 014 at a frequency of 50 and 22 kHz, respectively. For the theoretical substantiation of the observed effects, changes in the dispersed and structural-group composition of marine fuel are studied. The analysis of indicators in accordance with the regulatory documents is carried out. The greatest changes in all studied parameters are noted at an ultrasonic vibration frequency of 50 kHz. It is found that, in comparison with the initial sample, the kinematic viscosity decreases by 15 % after ultrasound exposure. The fuel density decreases by 0.002 kg / m3, the flash point of the fuel drops by 5 °C, and the cetane number shows a tendency to decrease by 2 points. The average particle size of the dispersed phase decreases by 12 %. An explanation for the improvement of the investigated fuel indicators on the basis of an increase in its degree of dispersion and redistribution of structural-group components is proposed. Ultrasonic treatment of marine fuel (50 kHz, 100 W, 43 s), carried out before feeding it to the engine on the fuel line in front of the filter and high-pressure pumps, can be used to improve the operational properties of the fuel and, consequently, reduce its consumption.

The subject of the research is modern marine turbomachines which differ in many types, designs, purposes, materials and working bodies. It is noted that this diversity is guaranteed by the use of modern computer technologies from the stage of preliminary preparation of production to the release of final products. The design stage of turbine units taking into account the external characteristics of the turbine stage - power, speed, efficiency, shaft torque and others is considered. The efficiency of the stage is expressed by the efficiency coefficient, which is determined by the energy losses available in the stage. Losses, in turn, are expressed by losses in each individual element of the turbine stage design. At the same time, it is noted that the losses in the nozzle apparatus are decomposed into friction losses, edge and end losses. The object of the study is the nozzle apparatus of a low-consumption inflow turbine. The subject of the study is the velocity coefficient of the nozzle apparatus of a low-consumption inflow turbine. The research method is numerical simulation of gas flow using computational gas dynamics. The purpose of the study is to compare the value of the speed coefficient of the nozzle apparatus obtained during a physical experiment with the results of numerical modeling of the nozzle apparatus with subsonic (narrowing) channels. The conducted studies have shown that low-consumption inflow turbines are characterized by small sizes that do not allow us to fully carry out a physical experiment. A graph of the dependence of the velocity coefficient of the nozzle apparatus on the Mach number is provided in the study. A good convergence of the values of the velocity coefficient of the nozzle apparatus obtained by the numerical method with the results of the physical experiment has been established. The velocity fields of the flow part of the nozzle apparatus are obtained in the range of the Mach number ranging from 0.66 to 0.88. The possibility of using numerical modeling for this type of nozzle apparatus is concluded.

It is known that for many years various polymer composite materials have been widely used in the design and manufacture of boats structural elements. The estimated service life of modern boats is, as a rule, at least 20 years, during which the necessary level of fatigue strength of such elements must be provided. It is noted that the problem of ensuring the design life of composite elements in the body of boats is currently being solved mainly by providing a reduced level of design stresses and analyzing operational experience. As a rule, any calculated estimates of the fatigue life of these elements are not carried out. At the same time, the need for such assessments is now obvious. In order to form a method suitable for such assessments, the main provisions of methods for fatigue life evaluations of elements made of layered composites in aircraft structures are considered. Based on the analysis of these provisions, a method for fatigue life and service life evaluations of the outer composite skin of the boat body is proposed. Using the proposed method, a test calculation of the outer composite skin of the boat body about 60 meters long made of intact fiberglass of the “rovimat” type with the laying layers at an angle of 450 and the same fiberglass with impact damages is performed. The results obtained have shown that the service life of the skin with impact damages is significantly less than the estimated service life of a boat of 20 years. The obtained result has shown the need to introduce periodic inspections and control of the outer composite skin during the operation of the boat.

For small vessels of the fishing fleet of the Crimean region, the problem of cargo safety is acute. Vessels are equipped with compression refrigeration units that do not provide the vessel with the required amount of cold due to the removal of the fishery from the base. In compressor refrigeration plants, electric energy is spent to perform the work of compressing the refrigerant. It is possible to use recycling absorption refrigeration units on such vessels. It seemed possible to use the energy of the exhaust gases to heat the water-ammonium mixture. Currently, the exhaust heat of the internal combustion engine is widely used for the operation of refrigeration plants and air conditioning systems. To achieve the required cooling capacity, it is possible to implement a two-stage cooling cycle, which entails an increase in mass-overall parameters of the equipment. As known, an increase in temperature of the cooling source negatively affects the cooling capacity. In the Azov-Black Sea basin in the warm period of the year, the water temperature reaches 25 °C. To ensure reliable operation of the absorption refrigeration unit, the circulation rate of the water-ammonium solution should be more than one. Otherwise, all the liquid will evaporate in the generator and the solution will not return to the absorber. It is not possible to absorb the vapour leaving the evaporator. At the same time increase of circulation multiplicity leads to increase of mass flow rate of circulating solution, which negatively affects mass-overall parameters of the unit. The effect of operational parameters of the utilization absorption water-ammonium refrigerator on the degassing zone is examined in the paper. It is shown that with the specified operating parameters, the degassing zone allows a single-stage cycle with the required cooling capacity.

The existing types of drives for ship deck lifting devices are analyzed in the paper; a rationale for the use of a hydraulic drive that is sensitive to load changes at designing such devices is provided. A typical feature of the most deck hoisting equipment is work in special conditions. The effect of wind, rolling, changes in the parameters of the “cable-load” system (its shape, mass, hydrodynamic and inertial coefficients, cable length), the transition from one medium to another one should be considered as special conditions. Non-stationary loads arising during the operation of this class of equipment occur not only during transient processes, but also during steady-state operation, which negatively affects their performance and reliability. One of the requirements for the drive of such equipment is the optimal operating parameters: speed variation in a wide range, possibility of reversing, implementation of smooth regulation of turnovers and torque, overload capacity. Both hydromechanical and electric drives meet these requirements. Therefore, for the optimal selection of the lifting devices drive of a fishing vessel during design, it is necessary to perform a dynamic analysis. The choice of a model for dynamic calculations depends on many factors corresponding to specific tasks. The mathematical models of electromechanical and hydraulic drive of a ship lifting device with a transmission mechanism and one engine are developed in the paper. Numerical simulation analysis has shown that the hydraulic drive has better recoverability to normal operation after a transient. Therefore, in the drive system of the lifting devices of a fishing vessel, it is more expedient to use a hydraulic drive capable of adapting to load variability.

A new nonlinear controller for direct flux and torque control (DFTC) of a doubly-fed induction generator (DFIG) based on a single-rotor wind turbine (SRWT) using the fractional-order second-order continuous sliding mode (FOSOCSM) controller is presented in this paper. Three different controllers are proposed to control the electromagnetic torque and rotor flux of the doubly-fed induction generator driven by a single-rotor wind turbine. The main goal of the proposed DFTC control structure is to improve the quality of the electromagnetic torque and stator current of the SRWT system by reducing electromagnetic torque undulations, stator current, and rotor flux undulations in the DFIG-SRWT systems. The mathematical model of the DFIG has been described. The descriptions of the modified space vector modulation (MSVM) strategy and the proposed FOSOCSM controller have been presented. The DFTC-MSVM control structure with proposed FOSOCSM controllers has been described. This proposed strategy has been shown to be robust and stable against parametric uncertainties and load electromagnetic torque. The validity, robustness, and effectiveness of the proposed DFTC-FOSOCSM technique are demonstrated through simulation studies in the MATLAB® software environment. Numerical simulation results demonstrate that the proposed DFTC control scheme with proposed FOSOCSM controllers has a faster transient response than traditional DFTC and DFTC with classical SOCSM controllers. Also, it reduces ripples in both electromagnetic torque of stator current, and rotor flux significantly compared to the classic technique and DFTC with traditional SOCSM controllers.

The use of relay protection of electrical power objects on ships is associated with the widespread use of the elemental base of computer technology. A relay protection system based on computer technology is a set of interacting computing facilities for processing information coming from a protected object to recognize its state. Important issues in the construction of such systems are the choice of information processing tools at individual stages of transformation and the organization of their interaction. In the general case, information processing in the relay protection system can be implemented using analog, digital (programmable) and hybrid computing devices. Analog computing devices have low versatility and require additional design developments when changing the information processing algorithm. Their most important advantage is to ensure high speed of the computational process. Digital computing devices are distinguished by high accuracy, versatility and can be used to implement various information processing algorithms within the limits of their technical capabilities. Hybrid computing devices contain analog and digital computing facilities, interacting on the basis of a single algorithm. Therefore, their speed, accuracy and versatility are determined by the degree of combination of these means. Applying the relay protection systems in ship electric power complexes, where relays can be used as independent products, is proposed in the paper. The possibility of using programmable logic controllers for organizing control and communication between system elements when using at each level of separate computing subsystems with parallel program execution is considered.