Full-scale tests of KRAB-400 seismic complex in summer 2017 have shown up a fair amount of hardware flaws. List of deficiencies and instructional guidelines contributed to rectification of all issues found within a short timeframe and to the development of a hardware system for full-scale pilot tests which were carried out at the test polygon in Pechora Sea nearby Prirazlomnaya platform. This is a standard area 30-35 m in depth well suited for seismic studies in transition zone with flat sea bottom covered with sediments. The key goal includes testing the KRAB seismic bottom stations during 2D seismic profiling as per the CDP method along with OBX750E Geospace sea-bed nodes, USA. The obtained seismic data are duly processed thus evidencing equipment service ability in real operation conditions. Good correlation of results for both types of equipment is demonstrated by independently plotted seismic sections. Due to geophones of lower frequency the KRAB results for vertical channels turn out to be even better in terms of transmission depth. The developed complex has shown the possibility to handle structural and geological tasks succefully. Substantially the complex of seismic bottom stations KRAB-400 ensures collection of seismic data as per good international counterparts. However, the reject rate of field data has achieved abnormally high 20.5%. This reject rate is associated with the low quality of technological assembly, which is a disadvantage of domestic production. It is summarized that Russia has a sufficient number of qualified personnel for the production of hightech products and solving the problems of import outstripping rather than import substitution.

A process of choosing the optimal route when ocean passage of sea vessel is reviewed in the paper. The criterion of optimality in this work is delivery time of a cargo. At the same time the characteristics of the vessel, including seaworthiness, are not taken into account. On the example of the voyage from the European continent to the Caribbean, the methods for assessing the advantage in distance when ocean passage along great circle route or loxodrome are formulated. Six ocean crossing routes from Europe to the Panama Canal, which may be used practically, are introduced. Methods for convenience and simplification of choosing route when preliminary plotting are recommended. On the basis of calculations and constructions performed in Electronic Chart Display and Information System, the process of calculating the advantage in distance, and therefore in delivery time, neglecting the vessel characteristics is shown. Passage along orthodrome is not always considered most expedient in this work. It is mentioned that during passage the difference in delivery time may vary due to influence of external factors that require further accounting and evaluation. Recommendations for choosing the optimal route without taking into account the characteristics of the vessel, for the vessels with electronic charts and for the vessels using only paper charts have been drawn up. Recommendations for preparation of a preliminary plotting are given. It is concluded that in order to achieve the maximum level of safety of navigation during ocean voyage, it is necessary to improve the results and conclusions obtained in this work, taking into account in the future the characteristics of the vessel and conditions that can influence on them.

The issues of simulation of complex transport hubs and systems are considered in the paper. The sea coal terminals, which are complex transport hubs that perform the final operations of railway transport and the initial operations of sea transport, which constitute a single transport process for the transportation of coal, are discussed in the paper. In international and domestic transport science, sea terminals are often considered as queuing systems, the basic principles and patterns of operation of which are explained using the methods of queuing theory. However, the use of exclusively queuing theory methods in the design and calculation of the performance indicators of marine coal terminals often leads to unreliable and underestimated results due to the large number of stochastic processes occurring at the terminals when servicing incoming transport requests. This is due to a significant number of latent factors affecting the quality and intensity of servicing transport requests, as well as the presence of internal parallelism of processes. In this regard, in the modern scientific community, the methods of computer simulation are recognized as the most adequate tool for solving such problems. The creation of digital analogs of complex sea transport nodes in computer programs and the further implementation of simulation experiments makes it possible to obtain much more accurate and visual results on the planned performance of sea terminals, and also provides reliable information about the degree of influence of certain factors on their work processes. The Anylogic environment is chosen for modeling. Using environmental elements, a digital copy of the rear cargo front of the marine coal terminal, which serves the requests of land transport, is created. A detailed explanation of the principles and approach to creating a digital model is provided, all the internal connections of the elements of the digital twin are clarified, and information on the options for setting up and controlling the model, and also brief information on the results obtained, is provided in the paper.

The problem of the optimal arrangement of the auxiliary fleet of a small shipping company that transports supply cargoes in the regions of the Eastern Arctic is discussed in the paper. The «small shipping company» term in the framework of the study means that the transport company has a small number of vessels (from two to three) under its management and carries out cargo transportation in one single direction. Since mathematical modeling and model experiment make it possible to speed up the process of making a managerial decision and bring it to a higher quality level, it is proposed, within the framework of the developed methodological support for the planning and management of the fleet of a small shipping company, to use one of the mathematical models of production planning of maritime transport and adapt it to the investigated technological process. It is known that one of the conditions for the successful development of the sea freight transport system and infrastructure modernization is the optimal use of the port fleet resources. For this reason, the object of optimization for the mathematical model is the process of performing offshore transshipment operations using the resources of the port fleet. The result of the study is a mathematical model for the arrangement of barges for the carriage of goods on a raid, which allows, among other things, to determine the optimal need for each type of available floating craft for handling ships arriving for unloading. When distributing the tug fleet, the option of attaching the thrust to the tonnage was considered, in which the tug changes the vessel in each port of the line, thereby achieving the maximum degree of utilization and the minimum costs for the maintenance of the tug per ton of cargo.

A simulation model of a container terminal which is used for the technological resources assessment is described in the paper. Container handling equipment and terminal area are considered as the primal resources. The main characteristics of the model include the graphical container flow model of a container terminal, which consider all container handling operations in a container terminal. Operations technology is divided into three main activities - get, move and put, which enable flexible selection of equipment type (technology). The variation of the container flow volumes and equipment productivity on each activity are considered. The study shows that the model provides more reliable assessment of container terminal resources. The simulation results are visualized by two types of graphics: the probability density of the necessary number of equipment and cumulative distribution function. Accordingly, the required terminal area is defined according to applied technology. The model configuration is based on seaports resource assessment; however, the same approach can be used for dry ports. The simulation tool can be utilized in various use cases, including monitoring terminal effectiveness and required developments against different container volume scenarios, operation strategies and comparison between different technologies. Accordingly, the tool can be utilized by consultants and equipment supplier sales representatives during early stages of port design.

The analysis of possibility of the soil liquefaction phenomenon occurrence at the base of navigable hydraulic structures is presented. It is noted that such structures are located, as a rule, in river valleys on alluvial soils, which are usually an alternation of layers of fine-grained or silty sand and loam. With an increase in the moisture saturation of the porous layer of soils, the angle of repose and adhesion between soil particles decrease, in addition, weighing forces begin to gain more and more importance. Under the static effect on the soils from the weight of the structure and the dynamic effects created during the operation of the navigational lock in the process of filling and emptying the chamber, the base soils acquire the consistency of a suspension, bonds between particles are lost, and the soils lose their bearing capacity partially or completely. This leads to off-design movements and settlements of navigable hydraulic structures, cracks in concrete structures, destruction of dowels in temperature-sedimentary joints between structural elements. As an example of the consequences of soil liquefaction for the state of navigable hydraulic structures, the situation at the lock No. 5 of the Volga-Don shipping canal is considered. Since 2005, significant vertical settlements of the central sections of the chamber have begun at the lock No. 5. The analysis has shown that the lock is located on fine dusty sands with low filtration coefficients, particles with sizes less than 0.1 mm make up more than 84% of the soil composition. With a high water saturation of the layers, the conditions for liquefaction had appeared. A similar situation takes place at the lock No. 2 of the Volga-Baltic waterway - fine and silty sands, full water saturation of the layer, poor fluid loss, low filtration coefficients in the soil led to the appearance of a crack in the concrete abutment of the lower head. To prevent the possibility of soil liquefaction, several approaches have been proposed: reducing the water saturation of the layer (anti-seepage curtains, drainage), supporting structures on soils with high bearing capacity.

The accuracy of various interpolation methods, used by specialists when working manually or technically implemented in software when plotting bottom relief on navigation maps of inland waterways, namely nearest neighbor interpolation, triangle based interpolation, bilinear interpolation and biquadratic spline interpolation, is analyzed in the paper. The study was conducted during the process of creating an electronic navigational chart of the Northern Dvina River. The aim of the study is to determine the interpolation method that guarantees the minimum deviation of the calculated values from the original values and the rendering of the least number of artefacts. In existing cartographic and geoinformation software, only interpolation methods based on regular grid calculations are used. In this study interpolation is performed on an irregular grid since depth sounding is carried out using a single beam echo sounder, and the depth grids obtained using this type of equipment are always irregular. This makes it possible to ensure the highest possible accuracy of the initial measurement during interpolation. The accuracy of the performed interpolation is verified by dividing all depths into two parts (longitudinal and transverse tacks) and calculating the depth values at longitudinal tacks using interpolation. The maximum discrepancies of up to 50 cm are detected when performing nearest neighbor interpolation. The minimum discrepancies of less than 10 cm are detected during biquadratic spline interpolation. According to the results of the study, biquadratic spline interpolation is the best method for building digital models of the bottom relief that can then be used to plot bathymetry on navigational charts.

The design of power drives of reloading equipment built on multi-stage ordinary gear reducers with high-hard cylindrical involute gears, which allow to dramatically improve the mass - load capacity of the drive, reduce metal consumption, reduce the weight of the drive by up to 50%, and ensure the production of compact energy-intensive devices, is considered in the paper. This is achieved, first of all, by increasing the hardness of the teeth and the rational distribution of the gear ratio over the steps. In previously published works, the distribution of the total gear ratio by stages was carried out by solving the problems of minimizing the objective function with a variety of criteria designed to assess the operational state of the gearbox. With this distribution of the gear ratio, regardless of the criterion that determines the degree of transmission load and is the basis for optimizing the gearbox parameters, inequalities, in which the gear ratio of the slow-speed stage is assigned a lower value than in the high-speed stage, are realized. Studies have shown that in a fairly wide range of gear ratios, the assignment of the gear ratio in each stage to the optimal value leads to the appearance of an unconstructive and non-technological mortise shaft-gear in the design, which excludes grinding the teeth as the last operation after heat treatment of the gears. Therefore, the use of two, three and four-stage cylindrical gearboxes with high-hard teeth on cranes when distributing the total gear ratio forces us to take into account the requirements related to the design and manufacturing technology of gears. In the proposed work, in order to exclude the mortise shaft-gear for the distribution of the gear ratio, a design and technological criterion is introduced in the form of a” threshold “ level that limits the largest gear ratio realized in one stage, and as a result, limits the largest gear ratio realized by the gearbox. Tables and approximating dependencies in the form of simple functions forming optimal values of gear ratios are proposed for reducers. These dependencies can be directly used in the design of gearboxes with improved gears. For gearboxes with high tooth hardness, the distribution of the gear ratio is based on the implementation of an inequality in which the gear ratio of a high-speed stage is assigned taking into account the “threshold” level while ensuring a given deviation of the gear ratios of the stages from the optimal values. This approach increases the diameter of the cavities, justifies the assignment of the gear ratio of the high-speed stage by a lower value than in the low-speed stage and eliminates the appearance of an unconstructive and non-technological mortise shaft-gear in the design.

The features of using the lean manufacturing tools in the ship repair industry are examined in the paper. The object of research is lean manufacturing in ship repair. The subject of the research is the lean manufacturing tools, methods and features of their application in the ship repair industry. The aim of the work is to study the features of ship repair for the lean manufacturing tools implementation. The objectives of this paper include the study of the distinctive characteristics of the ship repair industry from the standpoint of lean production and scientific organization of labor, the study of the experience of other shipyards in lean ship repair, the study of the concept of ideal ship repair from the standpoint of lean production. The main methods for solving the tasks set include the use of the benchmarking tool and the analysis of literature sources to systematize data on the lean manufacturing tools implementation at shipyards; observations, surveys, questionnaires, as well as experience in the shipbuilding industry, in particular, in the management for the development of the production system. The shipyards of the USA and Japan are examined; the applied tools of lean production and their connection with the increase in labor productivity, savings in finances and labor costs, as well as the difficulties in their development and distribution are shown in the paper. Lean production, the foundations of which were laid in the scientific organization of labor, is more focused on rhythmic conveyor production, and is not used in full in the ship repair industry. The applicability of the lean manufacturing tools can be different not only depending on the industry, but also from enterprise to enterprise in one field of activity. In contrast to lean production, in the scientific organization of labor, based on the peculiarities of ship repair activities, some waste was allowed.

During the passenger ships operation, significant trim changes with a constant displacement due to the movement of passengers are possible. As a rule, in the design of same ships, model tests are not carried out, and the calculations of the propulsion are made by the prototype or using methods based on serial tests. Resistance curves, calculated in this way, correspond to trim on an even keel, which can lead to errors in determining the required power, the achievable speed and the required parameters of the propulsion system. To determine this influence in the experimental basin of the Admiral Makarov State University of Maritime and Inland Shipping, the towing tests are carried out. Ship model has shape form and dimension ratios, typical for excursion ships of St. Petersburg: length to breadth ratio - 4.0, breadth to draft ratio - about 7.1, block coefficient - 0.57. The curves of the rest resistance coefficients are given for three sitting options - on an even keel, with trim to the bow and trim to the stern. The curves for the model on even keel and with trim to the stern almost coincide, and trim to the bow leads to an increase in the residual resistance coefficient by up to 1.0 ∙ 10-3. Tests are carried out in calm deep water conditions for Froude numbers from 0.14 to 0.35. It is shown that the effect of trim on resistance depends on the ship speed. When designing propulsion systems for small passenger ships, it is proposed to add an allowance to the values of the resistance coefficient in order to take into account possible trim changes.

It is noted that the shipping industry makes a significant contribution to the total emission of carbon-acid gas into the global air basin due to the combustion of fossil hydrocarbon fuels by ship power plants. In April 2018, IMO adopted an ambitious new strategy to reduce greenhouse gas emissions for shipping. In accordance with the adopted strategy, it is planned to gradually reduce the average intensity of carbon dioxide emissions per ton-mile by 40 % by 2030 and by 70 % by 2050. This study examines the main directions of improving the modern fleet, including: improving the logistics of transportation; further improvement of the quality of the vessel hydrodynamic parameters; improvement of the characteristics of power generating equipment and units of the ship power plant systems; replacement of the used fossil fuels with alternative ones, which are potentially capable, with an integrated approach, to ensure the tasks fulfillment set by the strategy. Attention is drawn to the fact that in terms of achieving the goals of the IMO strategy, the use of alternative fuels is of particular importance, as a direction that can provide up to 100 % reduction in greenhouse gas emissions. The various possible options for alternative fuels, including liquefied natural gas, carbon-neutral fuels based on carbon - biofuels and synthetic fuels (electric fuels), and carbon-free fuels are considered and the prospects for their use are also analyzed. The peculiarities of the transition to alternative power sources for ship power plants for various segments of the world fleet are considered in the paper.

The problem of identifying the parameters of electromechanical systems has long been relevant and in demand for practice. For the most part, the well-known approaches to identifying the parameters of electromechanical systems under study are based on the use of linear models that are not suitable for most systems with nonlinearities. In the case of a servo drive, non-linearity and some uncertainty occur in the mechanical part of the drive, due to the presence of friction, elasticity and backlash. In this regard, many different methods and algorithms for identifying mechanical parameters have been developed for servo drives, which include nonlinear least squares estimation, the finite element method, and methods based on spectral analysis. A method for determining the moment of inertia and the coefficient of viscous friction for servo drives, based on the use of the dynamic equation of the mechanical drive system, is discussed in the paper. The torque and the actual rotational speed of the machine are used as input information. Accurate identification of the mechanical parameters of an electric drive is essential for the synthesis of its control system. The developed method is resistant to external influences, such as measurement error, mechanical resonance of the drive system. The revealed parameters can be used for autotuning the gains in the speed controller, which will provide high performance control of the drive speed. The effectiveness of the proposed method is confirmed by computer simulation and experimental data.

In recent years, semiconductor power converters have been increasingly used in marine electric power systems and electric propulsion systems. Semiconductor power converters are used in a frequency-controlled electric drive, including a rowing electric drive, combined pulse installations, valve generator sets, including halogen generator sets, in shore power devices. The use of semiconductor power converters leads to a decrease in the quality of electricity in the ship’s network, in particular, the coefficient of harmonic voltage components increases. The rules of the Russian Maritime Register of Shipping (RS) regulate the quality of electricity and maximum emissions in the ship’s network, which is necessary for the proper functioning of ship electrical equipment. To solve the problem of electromagnetic compatibility of electrical equipment and improve the quality of electrical energy in the ship’s network, the various solutions are used. In particular, the traditional methods of improving the quality of electricity should include the separation of electrical networks using electric machine converters, transformers, additional installation of filter-compensating devices, connection of semiconductor power converters using three-winding transformers, etc. At the same time, on modern ships, the solution to the problem may be associated with the use of a new type of semiconductor power converters, made on the basis of active rectifiers, and the use of electric power systems with direct current electricity distribution, in which valve generator sets and valve static electricity sources are used as power sources. The structural schemes of traditional and electric propulsion systems, as well as promising circuit and technical solutions to solve the problem of electromagnetic compatibility are discussed in the paper. The analysis of technical solutions allowing to reduce the coefficient of harmonic components of the voltage in the ship’s network and to ensure electromagnetic compatibility of ship electrical equipment is given.