Vol 5, No 3 (2026)

BACKGROUND: Modern automation systems for marine power plants operate using threshold-based protection algorithms that are unable to detect actual equipment failures or signal distortions in measurement channels. This study is motivated by the need to prevent false alarms, which can lead to unplanned downtime, financial losses, and a gradual decline in operators' trust in the automation.

AIM: To develop a mathematical model of the signal from the rotation speed measurement channel of a marine unit to determine diagnostic criteria for a faulty condition, and, based on the constructed model, to develop a real-time fault detection algorithm for the measurement channel that automatically blocks the equipment from entering emergency operating mode.

METHODS: The study employed a high-frequency inductive sensor. Mathematical modeling of the speed measurement channel signal and debugging of the diagnostic logic of the fault detection algorithms were implemented in the SimInTech software environment.

RESULTS: A mathematical model of the speed measurement channel was constructed. A method for detecting faults in the speed measurement channel with deterministic diagnostic criteria was developed. An algorithm for blocking the protective functions of the automated control system is proposed to prevent the marine unit from entering emergency operation mode or shutting down.

CONCLUSION: The proposed method does not place excessive demands on controller computing resources, has transparent decision-making logic, and meets functional safety standards. The solution can be integrated into standard automated control system software environments, reducing the likelihood of false alarms and increasing the operational reliability of ship propulsion systems.

BACKGROUND: Modern production processes require the use of integrated digital technologies that ensure rapid changes to the product design and reduce the time of production preparation. The development of a comprehensive design methodology for the hull of a marine unmanned vehicle, taking into account adaptive production technology, makes it possible to increase the flexibility of the production system, ensure the rapid adaptation of production processes to new requirements, and minimize the time to bring new products to the serial production stage. There remains a need to increase the efficiency of the development and production of marine unmanned vehicle hulls in the face of constantly changing requirements for their design characteristics.

AIM: To develop a comprehensive methodology for designing the hull of a marine unmanned vehicle, taking into account adaptive production technology and changing performance requirements.

METHODS: Integration of digital modeling of the design stage and the technological process, based on the integration of CAD/CAE/CAM/PLM.

RESULTS: An approach to the formation of a comprehensive methodology combining the means of computer-aided design, engineering analysis, production preparation, and production process management is proposed.

CONCLUSION: This approach makes it possible to reduce the time required for product development, improve the quality of hull manufacturing, and ensure prompt changes to the design without significantly increasing production costs.

BACKGROUND: The challenge of automating Computer-Aided Process Planning (CAPP) in mechanical engineering remains relevant. Existing CAD/CAM systems fail to provide end-to-end design due to insufficient integration, deterministic algorithms, and the disconnect between design and manufacturing data. As a result, process engineers are forced to spend considerable time on routine operations: searching for information across disparate reference databases, manually transferring parameters from drawings to process sheets, and repeatedly entering the same data into GOST-compliant documentation. This reduces responsiveness to schedule changes and increases overall production costs.

AIM: To develop a technical specification and justify an information-logical model based on a directed acyclic graph that enables automated route generation, reduces technological preparation time, and improves decision quality through semantic data connectivity.

METHODS: The proposed solution is an information-logical model based on a directed acyclic graph. The model relies on five integrated reference databases (materials, equipment, tooling, standard solutions, and quality control), which formalize the process. The system's operational algorithm is described: process routes are automatically generated based on the 3D model geometry and a knowledge base, while the process engineer verifies them, with provision for machine learning.

RESULTS: Implementation of this approach reduces technological preparation time and enhances production transparency. This creates a solid foundation for integration with Manufacturing Execution System (MES) and Enterprise Resource Planning (ERP) systems and for implementing the digital twin concept.

CONCLUSION: Using the developed information-logical model shortens the technological preparation cycle and speeds up decision-making.

BACKGROUND: The importance of calculating high-order nonlinear forces has been confirmed by numerous theoretical and experimental studies. Of particular importance are nonlinear forces caused by the sum and difference of frequencies, which can cause long-period oscillations of ships and offshore structures and lead to fatigue stress. Therefore, determining these forces under natural irregular wave conditions is a pressing issue.

AIM: To develop a method for calculating nonlinear forces caused by the sum and difference of frequencies under irregular wave conditions.

METHODS: To calculate nonlinear forces, the integral equation method and the spectral method are used.

RESULTS: A method for calculating nonlinear forces caused by the sum and difference of frequencies in irregular waves has been developed and validated. Calculations of nonlinear forces induced by the sum and difference of frequencies were performed for various types of vessels under irregular wave excitation. The results obtained for different vessel types and various frequency combinations are analyzed.

CONCLUSION: The paper describes a methodology for calculating nonlinear forces due to the sum and difference of frequencies in irregular waves. An increase in nonlinear force values in irregular waves is demonstrated with increasing wave severity. It is shown that nonlinear forces due to the sum of frequencies under irregular wave conditions exceed those due to the difference.

BACKGROUND: Russia is facing a shortage of domestic dredging capacity caused by the withdrawal of Western companies from the Russian market. At the same time, the dynamics of cargo turnover in Russia's sea basins show that the need for dredging is becoming increasingly acute and requires a comprehensive approach to the development of trailing suction hopper dredgers. The two size classes of these vessels offer the highest logistical efficiency: the "Small" dredger, capable of moving between basins via inland waterways by meeting the dimensional restrictions of the White Sea–Baltic Canal, and the "Large" dredger of almost unlimited capacity for sea routes. The priority task is the design of the Small dredger.

AIM: To develop a concept of the Small Trailing Suction Hopper Dredger by determining its primary design characteristics for the subsequent preparation of a technical specification.

METHODS: Statistical data analysis from international directories, shipowner data, and classification societies. A sample filtering method based on the dimensional constraints of inland waterways was applied.

RESULTS: The primary characteristics of the Small Trailing Suction Hopper Dredger are determined: hopper volume ≤4,000 m³, ice class Ice1, navigation area R1. The choice of the bottom discharge system and the aft superstructure arrangement is justified.

CONCLUSION: The target vessel is similar to the TSHD2000 project operating in Russia, but is characterized by greater operational flexibility. The obtained primary characteristics will serve as the basis for further project development: determination of secondary characteristics, performance evaluation, and comparison with existing and prospective vessels.

This article studies the causes of biofouling and methods to combat it. The problem under consideration is relevant to the development and operation of marine structures (ship hulls, underwater vehicles). Fouling leads to increased corrosion rates and degraded tactical and technical characteristics—an increase in mass, a decrease in speed, etc. The review examines the process of fouling of structures during prolonged exposure to seawater and presents a brief chronology of the development of antifouling coatings—from the earliest mentions to modern methods of combating biocenosis. The main types of antifouling coatings currently in use are identified: diffusion, contact, self-polishing, and non-biocidal. The fundamental mechanism of their operation is analyzed, and the criteria affecting the effectiveness of different coating types, as well as their advantages and disadvantages, are determined. Specific brands of domestic and foreign coatings are listed, along with their characteristics and operating conditions. Based on the analysis, the main areas of application for different types of antifouling coatings have been identified, the key factors determining their selection have been indicated, as well as the requirements for modern antifouling coatings being developed—a long service life (at least 5 years) and prolonged exposure to open air (at least 1 year).

BACKGROUND: Correlation processing of signals in a passive multi-position meter is based on the fact that the cross-correlation function is recovered from the received signal realizations at different positions according to the primary parameter—delay—and the current measurement of the primary parameter—the signal arrival time delay relative to the reference—is determined from the position of its maximum on the delay axis. For signals with a wide spectrum, the width of the main lobe of the cross-correlation function is small, and it is not difficult to perform this measurement within the required accuracy. For signals with a narrow spectrum, the width of the main lobe of the cross-correlation function becomes so wide that accurately measuring delay readings becomes very difficult. Additionally, with limited accumulation time, the potential accuracy of correlation measurements for signals with a narrow spectrum decreases. All these factors make the use of correlation meters challenging for narrow-spectrum signals and make the problem pressing.

AIM: To improve the accuracy of coordinate measurements of a multi-position passive meter for continuous radiation sources by means of correlation processing of narrow-spectrum signals with unknown parameters.

METHODS: A method is used for improving the accuracy characteristics of passive multi-position meters when receiving narrow-spectrum signals, based on transforming the original signal spectrum to narrow the main lobe of the autocorrelation or cross-correlation function of the received signal.

RESULTS: The considered method reduces the root-mean-square error in determining the location of a narrow-spectrum signal source by more than 10 dB.

CONCLUSION: The considered method for improving the accuracy characteristics of passive multi-position meters when receiving narrow-spectrum signals, based on transforming the original signal spectrum in order to narrow the main lobe of the autocorrelation or cross-correlation function of the received signal, can be successfully applied in the design of passive multi-position measurement systems.

BACKGROUND: During operation of icebreakers and ice-going ships, the propeller interacts with ice, producing impact loads and subsequent oscillatory processes in the propeller–shafting system. These processes determine the stress-strain state of the propulsion complex components and should be taken into account in strength assessment.

AIM: To determine quantitative characteristics of the shock-oscillatory process in shafting systems of ice-going ships and to evaluate the influence of the shape, intensity, and duration of impact force on oscillation parameters.

METHODS: A linear model of damped oscillations is considered; the superposition principle for elementary impulses, Simpson numerical integration, and statistical modelling of ice loads based on full-scale strain-gauge measurements are used.

RESULTS: Oscillation amplitude is mainly governed by the steepness of the force front and by impact intensity, whereas the product of force and impulse duration is not a reliable characteristic of the impact process. For repeated impacts, a calculation algorithm is proposed for a discrete strain sequence reproducing real strain records.

CONCLUSION: Statistical modelling makes it possible to obtain time histories of ice loads comparable with full-scale shaft strain-gauge measurements and can be used for computational assessment of loads on shafting systems of ice-going ships.