Corrosion and biofouling impose serious hazards to the normal operation of marine propellers. The current research on the protection methods for marine propellers focuses on the propeller material itself, with insufficient attention to the propeller protective coating technology. This study introduces the anti-fouling principle of low surface energy fouling-release coatings and the development of relevant technologies, discusses the prospects and development directions of organosilicon-modified low surface energy anti-fouling coatings applied to marine propellers, and looks to the future development of anti-fouling coatings for marine propellers.

The epidemic prevention assistant robot refers to an automated device designed to assist crew members in epidemic prevention. In maritime epidemic prevention, the application of such robots onboard helps reduce the workload of crew members and mitigate the risk of epidemic transmission. Based on existing technical documents and market product information, combined with practical requirements, this study analyzes the feasibility of deploying two conventional functions—delivery and disinfection—of epidemic prevention assistant robots on ships. It further compares and analyzes their advantages over alternative methods. To implement the delivery and disinfection function of the robots onboard, the adaptability of key technologies for these conventional functions of the epidemic prevention assistant robots is demonstrated and analyzed around the issues such as ship oscillation during navigation and limited compartment spaces. Technical recommendations for shipboard robot applications are then provided.

With the increase of the installed engine power and redundancy requirements, the specification of the engine room ventilation system has been expanded, imposing difficulties on the design and layout of the engine room. A compound engine room ventilation system is introduced by combining frequency conversion fans and water-cooled internal circulating system. The CFD method is utilized to simulate a ship under several basic working conditions, optimizing the parameters of engine room fans, the layout of engine room air coolers, and the nozzle angles of jet fans. The results show that the compound engine room ventilation system effectively reduces the specification of the engine room ventilation with improved economy and flexibility. It can provide a reference for the design of engine room ventilation system for similar vessels.

Hydrogen fuel cells have emerged as an important development direction for future marine power sources. With rapidly increasing complexity in ship power systems, traditional document-centric systems engineering methods fail to meet the research and development demands for rapid iterative of hybrid power systems. To address this, a design and verification method is proposed for the hybrid power system of hydrogen-fueled ships based on Model-Based Systems Engineering (MBSE) method. Firstly, the SysML language is employed to perform the hierarchical decomposition modeling at the overall, system and subsystem levels according to the requirement definition, functional analysis and logical design based on the overall engineering requirements. The functional logic rationality of the model is then verified through the integrated simulation verification of the model. Finally, a Simulink simulation model is built to simulate and calculate the performance parameters of the hybrid power system of the hydrogen-fueled ship. The feasibility of the design and verification process and the effectiveness for the design iteration of complex systems are validated on the hybrid power system of a hydrogen-fueled ship. It can provide a reference for the application of MBSE method in other ships.

The migration of China's ship design software to domestic platforms becomes crucial for enhancing national innovation autonomy and reducing technological dependence against intensifying international competition. However, conventional domestic cross-platform strategies, such as system reconstruction or Browser/Server (B/S) architecture conversion, remain incompatible with ship design software. The domestically developed NuCAS system is examined to explore a new cross-platform migration strategy for message mechanisms applicable to shipbuilding industrial software. Through in-depth analysis of the technical framework and code structure of the message mechanism of the NuCAS system, multiple migration strategies are evaluated to innovatively proposed a migration strategy that rewrites the underlying core message mechanism of MFC (Microsoft Foundation Classes, a Windows API class library) based on the cross-platform Qt framework while preserving the upper-layer application code. This strategy successfully resolves the challenge of the seamless conversion of message mechanisms between MFC and Qt frameworks. The results demonstrate that the modified NuCAS system operates stably on domestic platforms, meeting the localization requirements of ship design software. It provides a groundbreaking approach for the cross-platform migration of message mechanisms in shipbuilding industrial software.

To address the issues of high training costs and low efficiency in conventional manual hull modeling methods, an intelligent software for 3D geometric hull model generation from 2D lines plan has been developed, enhancing the automation of modeling and production efficiency. This modeling software, which is developed and designed using python, simulates the human visual system to extract, analyze and interpret the hull lines information from 2D drawings in units of pixel clusters. First, it reads, identifies and processes 2D lines plan (JPEG or PNG format) obtained from screenshots or scans, and maps the 2D profile points to 3D point cloud data according to the spatial relationships among the three views. Then, it generates the hull surface through information densification, thereby simplifying the modeling process from 2D plans to 3D models. Finally, accuracy verification results show that the modeling software based on computer vision technology can quickly convert the 2D lines plan in image form into the 3D hull models, demonstrating its reliability.

A three-dimensional (3D) parametric modeling method is proposed for structural design, combining a design logic-based modeling approach with a parametric modeling approach. By utilizing the linking mechanism of CATIA V6 software, the structural design hierarchy and 3D modeling hierarchy are unified, reflecting design relationships through model associations among 3D features to form a layer-driven 3D model. The user-defined feature-based parametric method addresses the stability limitations of traditional modeling methods while enabling batch control of design objects through parametric tools, significantly improving design efficiency. Furthermore, this method has been applied to the structural design and preliminary design calculations for a ship’s cargo hold, with results being validated. The presented method can provide references for the 3D structural design of other ship types.

In the era of digital transformation, to address uncertainty, improve quality and efficiency, and enhance enterprise profitability, integrating digital technology into ship design technology to reconstruct a full three-dimensional (3D) ship design model has become a design development trend. A model-based integrated 3D digital design definition and technical connotation are proposed by using Hexagon Smart 3D as the 3D design platform. The solutions for 2D-driven 3D rapid modeling, integration of CAD/CAE, integration of detailed design and production design, 3D submission for approval and design tool development are also discussed. A number of design tools are developed based on parametric modeling and knowledge-driven approaches, forming a modeling strategy and design master schedule (DMS). This addresses the integration of CAE/CAD and the integration of detailed design and production design, enabling the share and reuse of the unified data sources and model data, as well as the 3D design collaboration among various design departments. The research results have been applied in merchant ships and cruise ships, laying a solid foundation for reconstructing the fully 3D design model of ships.

Considering that the research on intelligent ship technology in China is still developing, intelligent ship systems have not yet been widely applied in large ocean-going carriers. The design principles are formulated for the intelligent ship system scheme of a 14 000 TEU container ship in compliance with the class notion requirements. According to the actual configuration of the hardware facilities for data sampling in the perception layer of this ship, an integrated architecture is developed by combining the intelligent ship integration platform with various intelligent application functions. The system composition, data utilization, and functional implementation of intelligent navigation, intelligent engine room, and intelligent energy efficiency management system are introduced in detail. The results indicate that the system can achieve intelligent upgrades in route optimization, system monitoring, energy consumption control, decision-making support, and ship management for operating ships. The network security protection strategies are implemented for the risks existing in ship shore data interaction. It provides the selection basis and optimization direction for the future engineering applications of integrated ship intelligence.

To improve the efficiency of ship entry into the lock chambers and intelligently guide the ship into the ship lift chambers safely and efficiently, the Markov decision-making model is used to model the ship entry process based on the reinforcement learning method. The model training results are compared to identify the optimal solution by setting different reward functions and time steps. Subsequently, an intelligent navigation aid system is obtained by software development. Finally, a sea trail is conducted by using a typical ship passing through the lock chamber. The results show that the optimal maneuvering strategy not only reduces the number of operations but also enables faster arrival at the destination. Furthermore, the theoretical entry time planned by the navigation aid system is 124 seconds shorter than the actual entry time, corresponding to a 34.4% reduction in entry time. The research can provide references for the intelligent guidance of ship entry into the lock chambers.

To address the complexities, high costs, and iterative challenges between theoretical research and practical deployment in the recovery process of multi-unmanned surface vehicles (USVs), a virtual-real simulation method and system have been designed based on virtual-real data synchronization mechanisms and high-fidelity rendering via Unity 3D technology. This approach enables simultaneous theoretical research and practical debugging, effectively reducing iteration cycles and lowering costs. The system comprises physical USVs, virtual USVs, and a USV virtual testing platform, and the corresponding method is implemented through this system architecture. Physical USVs generate motion state data through their hardware, software systems, and recovery control strategies, while virtual USVs produce corresponding data through simulations. Through real-time synchronization and interaction of virtual-real data, the constructed USV virtual testing platform facilitates high-fidelity state monitoring, intuitive visualization, and high-confidence validation of recovery strategies. Comprehensive experiments indicate that this method can replace large-scale physical deployments with small-scale physical tests, fully integrating the advantages of real hardware and virtual environments to enable efficient, safe, and low-cost validation of multi-USV recoveries. Furthermore, the designed virtual-real simulation method and system provide a convenient and efficient testing platform for validating the recovery process of larger-scale USV formations and clusters.

Autonomous navigation systems serve as the foundation for unmanned surface ship operations, with local path planning algorithms being crucial components of these systems. The local path planning algorithms for unmanned surface ships are systematically reviewed, focusing on commonly used algorithms including the A*, Artificial Potential Field, Rapidly-exploring Random Trees, Dynamic Window Approach, Velocity Obstacle and intelligent optimization algorithms. It analyzes their fundamental principles, strengths and limitations, and summarizes their applications in path planning of unmanned surface ships. Current local path planning algorithms have demonstrated practical utility in simple scenarios such as open waters. However, significant challenges remain in complex situations, primarily due to high-density unstructured navigation environments, highly dynamic and strongly nonlinear environmental disturbances, and multi-constraint, multi-objective mission scenarios. It is recommended to further investigate the constraint-loading mechanisms of maneuvering motion models, advance multi-algorithm collaborative planning theories for full-mission scenarios and develop large model-driven decision-making and planning methodologies for unmanned surface ships. These efforts aim to address local path planning challenges in complex environments and missions. It can provide systematic references for theoretical research and engineering applications of local path planning technologies for unmanned surface ships.

Maritime autonomous surface ships (MASS) represent a critical direction for the development of current maritime industry. Their health development requires support from a comprehensive equipment system. Aligned with the International Maritime Organization’s Maritime Autonomous Surface Ships Code framework, this study focuses on the implementation of remotely operated vessels with autonomous capabilities. Through systematic analysis of the technological requirements for autonomous marine equipment, this study investigates the establishment of an overall architectural framework, a supporting equipment system, and processes for autonomy design and level evaluations. The key points and recommendations for the research and development of onboard autonomous functional systems and digital-intelligent equipment are proposed. It provides a systematic framework for the commercial application of autonomous ship equipment.

Azimuth waterjet propulsion system can broaden the navigation range of the ship, enhance the adaptability of ships in the shallow water area and other complex environments, and improve the mobility of the ship, which has a wide range of application prospects. In this paper, the numerical simulation was applied to investigate internal flow of azimuth waterjet propulsion system, the accuracy of numerical simulation was validated by experiment. The thrust and efficiency at different speeds were compared, the entropy generation rate is introduced to evaluate the loss ratio of different hydraulic component, the internal flow fields of azimuth waterjet propulsion system were analyzed in detail to reveal the flow mechanism caused by the variation of speed, which will provide guidance for the optimization design of azimuth waterjet propulsion system.

To investigate the flow field characteristics of a low specific speed axial flow pump under different flow conditions ( Q/ Q _des=0.9, 1.0, 1.1), the particle image velocimetry (PIV) technique is employed to measure the axial cross-sections of the pump at four locations: upstream of the impeller, inside the impeller, inside the guide vane, and downstream of the guide vane. And the pressure transducer is used to obtain the pressure distribution of the wall in the flow field of the pump. The results indicate that the velocity distribution upstream of the impeller shows consistent trends with axial acceleration along the axial direction under all three working conditions. A large velocity gradient is observed inside the impeller at different phases, displaying obvious acceleration near the hub along with concentrated high-speed regions. The velocity distribution inside the guide vane is similar, with more uniform high-speed regions and more stabilized flow under the design flow rate. The flow velocity downstream of the guide vane gradually increases in the mainstream direction, slowly accelerating at low flow rates and rapidly approaching the velocity in the mainstream region at high flow rates. As the flow rate increases, the pressure values at the monitoring points in the pump flow channel decrease. The main frequency of the pressure fluctuation is the blade passing frequency. And the pressure transition between the impeller and the guide vane gap is relatively smooth under the design flow rate with reduced flow losses. The experimental results can provide references for the design and performance optimization of the axial flow pump.

An ensemble deep transfer learning method for fault diagnosis based on soft voting is proposed for diagnosing waterjet pump faults under variable working conditions. The source domain and few target domain data samples are normalized after FFT transformation and then fed into three deep transfer learning diagnosis models for training: the CORAL based deep transfer metric learning model, the MMD based deep transfer metric learning model, and the transfer component-based deep belief network. The target domain test samples are diagnosed and analyzed based on this approach. An ensemble deep transfer diagnosis model is subsequently established by combing the soft voting method to obtain the final diagnosis results. Through the diagnosis of three different types of faults in waterjet pumps under variable working conditions, the results show that the proposed ensemble deep transfer diagnosis model not only effectively addresses the high-precision fault diagnosis of waterjet pumps under variable working conditions, but also has better diagnostic accuracy than the single deep transfer fault diagnosis model.

In view of the continuous technological innovation in marine engineering and the growing demand for enhanced adaptability to complex sea conditions, the binocular vision-based KCF (Kernelized Correlation Filters) algorithm is used as the target detection method based on the wave compensation device detection system. Based on the binocular vision, this method detects the load motion, capture the image feature points, calculates the position of the load in the inertial reference frame through coordinate system transformation, and monitors the spatial position and attitude of the replenished object in real time. The relative movement between the load and the replenishment ship can be eliminated by controlling the six-degree-of-freedom motion of the load, thereby achieving wave compensation. Program is developed under the Ubuntu system based on the robot operating system (ROS). Comparison and simulation are then conducted with a wave compensation prototype to validate the feasibility of the proposed detection and tracking method. The results indicate that this method is suitable for wave compensation systems.

Hydraulic calculations of complex pipe networks are generally solved by professional software. This study investigates the process of recursively modeling complex pipe networks and solving their hydraulic calculations based on a recursive algorithm. An algorithm of oscillatory convergence and alternately driving recursion is proposed to address the multi-path recursive states arising from multi-inlet complex pipe networks, whose calculation results fully comply with the requirements for pipeline calculations in engineering fluid mechanics. The calculation program developed according to this algorithm enables one-click import of the pipe network models and directly calculate the flow rates and the pressure distribution of the pipe network. The program code is highly encapsulated and portable. In the final section, the fire-fighting system of a domestic luxury cruise ship is analyzed. The program directly calculates the flow rates and the pressure distribution after simplified modeling, determines the fire-pump parameters, and identifies the critical locations of the pipe network, which provides guidance for the design. The results show that the proposed algorithm and program can calculate complex pipe networks. It can provide a calculation reference for the design of complex pipe networks and even the determination of the principal parameters of the system.

To meet the degaussing service requirements, the phase lag of the eddy current magnetic field in conductors needs to be studied and calculated for better magnetic compensation of conductors. A method for calculating the phase lag angle of the eddy current magnetic field in the conductors has been proposed based on magnetic variation simulation method. Firstly, the calculation method of the phase lag angle of the eddy current magnetic field in the conductors is deducted theoretically. Subsequently, the external excitation magnetic field is applied in the conductor space by using the magnetic variation simulation method in the COMSOL software, and the simulation results are consistent with theoretical calculations with an average error of 0.025%. Finally, the eddy current magnetic field measurement experiment is carried out to validate the accuracy of the theoretical and simulation results, with an average error of 2.48%, satisfying engineering requirements. The simulation analysis and experimental validation therefore show that this approach enables rapid and precise calculations of the phase lag angle of the eddy current magnetic field at different frequencies, which can be used in practical engineering calculations.

Island rescue vessels need to navigate shallow waters and dock at small piers on reefs, so their displacement is usually limited. The arrangement of various rescue equipment within a confined space is challenging, necessitating appropriate trade-offs. By establishing a quantitative assessment method for rescue capabilities, combined with the overall performance and rescue equipment configuration of different design schemes, the rescue capacity of the vessel can be evaluated in the early design phase to ensure it meets mission requirements. This assessment method has been successfully applied in the design of relevant island rescue vessels.

Surface unmanned vessels often operate in complex environments and require the ability to autonomously plan routes offline. Existing technologies rely heavily on long-range target recognition, while close range optical recognition can effectively serve as a perceptual tool to compensate for deficiencies. Although the marine environment is constantly changing, common target objects for recognition include reefs (on the water surface), islands, offshore production equipment (such as offshore wind turbines), and various types of ships. The images collected from marine environments have the characteristic of grayscale gradient. This article conducts theoretical simulation experiments on the effects and computation time of slant transform, Haar transform, slant Haar transform, Walsh Hadamard transform, Discrete Cosine Transform (DCT), and commonly used differential operators in extracting edges of common targets on water. Based on accuracy and noise resistance, Slant Haar transform was selected as the edge extraction operator to find the image attention area. Then use Hu invariant moments to identify the characteristics of ships in different driving states, providing a new technical approach for edge detection and recognition of common targets on water surfaces.

As an energy-saving and resistance-reduction device installed on the stern transom plate of the ship, the interceptor has been increasingly applied to medium to high speed ships. A medium-high speed displacement ship in oblique flow is numerically simulated by using the computational fluid dynamics (CFD) software STAR-CCM+ to study the influence of the interceptor and its installation configurations on the hydrodynamic performance of the ship in oblique flow. The calculation results show that the installation of interceptors on both sides reduces the ship resistance by 2.7%~5.9% under the oblique flow condition. However, as the drift angle increases, the improvement of the near-wake flow, such as hollow and rooster tail flow, by the interceptor gradually weakens, resulting in reduced resistance reduction rate of the interceptor. Additionally, the blocking effect of the interceptor on the bottom flow generates high-pressure hydrodynamic loads at the stern, thereby increasing the yaw moment of the ship. It is therefore recommended to deploy interceptors on both sides or only on the lee side during oblique navigation. These findings further reveal the role of the interceptors, which can provide guidance for the decision-making of its use.

The impact of the new strategy on reduction of greenhouse gas (GHG) emissions from ships by the International Maritime Organization (IMO) on the ship retrofitting market has been evaluated and studied. By analyzing the compliance with existing ship regulations and shipbuilding resource endowments at home and abroad, a detailed study is conducted on the impact of the implementation of the new strategy on the size, structure, regional differences, characteristics of the ship retrofitting market and the strategy of shipbuilding and ship repair enterprises. It shows that the implementation of IMO’s new strategy will promote the expansion of the global shipbuilding market based on green transformation, with an expected market size of 4 billion to 40 billion dollars. Additionally, it will drive the ship retrofitting market restructuring toward areas such as hydrodynamics, alternative fuels and post-processing technologies. It also promotes diversification, differentiation and customization in the shipbuilding and ship repair industry, providing data basis for market layout, strategic adjustment and resource allocation in the global shipbuilding and ship repair enterprises.

In 2024, the global offshore market witnessed a countertrend rebound with a double-digit surge in order values, indicating a renewed market recovery. Optimistic signals have emerged in the current offshore market. On the demand side, the expectation of international oil prices stabilized around $70 per barrel with minor fluctuations. The emerging nations continue to show great potential in offshore oil and gas exploration. Under the background of offshore oil accelerating towards the deep seas, orders for large-scale high-value oil and gas equipment such as floating production storage and offloading units (FPSOs) and floating liquefied natural gas systems (FLNGs) remain substantial. The rapid growth in demand for the offshore wind market and the imbalance in ship supply among various countries are still intensifying. On the supply side, the supply of the fleet will keep tight, and the production load of shipyards will remain full. Additionally, increasing stringent green and environmental protection requirements in maritime field are accelerating the demand for fleet renewal and the green transitions among offshore shipowners, in order to meet the new specification requirements.

The global new shipbuilding market achieved historic growth in 2024, with three major shipbuilding indicators of new order, completions and orderbook reaching highs since 2007, 2012, and 2010, respectively. China's shipbuilding industry continues to lead global growth, setting new historical records in main indicators and consolidating its leadership position in global shipbuilding. Since the onset of market recovery, driven by both internal and external factors, the global new shipbuilding market has been on the rise, reaching new milestones. The future market trend has become a critical focus for the shipbuilding industry and its upstream and downstream sectors. Analyzing the factors that influence the new shipbuilding market, quantifying potential variables, forecasting market trends, and stabilizing the expectations of sustainable development in the shipbuilding industry have become important tasks in the research of the market and industry. It provides a reference for the stable development of the ship industry by reviewing the development of the global new shipbuilding market in 2024, analyzing the influencing factors in 2025, and predicting future trends.

The secondary flow is the concomitant flow of the mainstream, which generally exists in nature and turbomachinery, most typically in the turbomachinery. The secondary flow in the turbomachinery not only changes the motion of the mainstream, deteriorates the flow field, induces the boundary layer separation, intensifies the jet wake at the exit, but also generates flow losses and noise. It is therefore of increasing concern of scholars and has risen to the same research level as the potential flow theory. Since 1950s, scholars at home and abroad have studied the phenomenon of the secondary flow from the perspectives of theoretical analysis, experimental research and numerical simulation, gradually understanding the flow mechanism and structure of the secondary flow in turbomachinery and establishing a continuously improving mathematical model, loss assessment and experimental methods for the secondary flow. Starting from the phenomenon of the secondary flow, the flow structure, mathematical model, and loss calculation and test methods of the secondary flow of the turbomachinery are reviewed and summarized. It is pointed out that the classical theoretical model of the secondary flow based on streamwise vortex built by ZANGENEH has some limitations. The key directions for future research are proposed based on the S3 flow surface theory of the secondary flow. It can provide references for the improvement of the flow field quality and the hydrodynamic performance of various types of turbomachinery, including waterjet pumps.

In ship design optimization, uncertainties in design variables or operational environments may prevent the ship performance from achieving the optimal objectives under the design conditions, and even lead to drastic performance deviations, causing the original design scheme to fail. The uncertainty-based design optimization method has been introduced into the ship design in order to mitigate the influence of uncertainties on the ship performance and enhance the robustness and reliability of ship design schemes. A mathematical model for the ship design optimization under the influence of uncertainties is established, along with its corresponding solution process. This method is then applied to the design optimization of a bulk carrier. The optimization results show that compared with the deterministic optimization scheme, the uncertainty-based optimization scheme is superior, and its robustness and reliability have been significantly improved.

The refrigerated container ship with AC440 V main distribution network cannot achieve the maximum loading capacity of the reefer container during the handling of the reefer containers at port or must turn on the main generator for power supply, due to the maximum capacity limitation of 6 300 A for the AC440 V air circuit breaker (ACB) and the limited capacity for the 4 800 kVA single step-down transformer. In the current study, the power can be supplied independently on both sides of the low-voltage main distribution board by adding one output panel on the traditional high-voltage shore power change-over panel and a step-down transformer to the main circuit. The capacity limitations of the ACB and the step-down transformer can then be solved to maximize the total capacity of the shore power system and achieve automatic safety interlocking protection and operation process guidance. It can effectively improve the safety of ship operation and economic benefits.

The temperature of the low sulfur oil may rise during the supply of diesel engines due to the influence of the environment of the machinery space in summer, resulting in low viscosity of the low sulfur oil at inlet causing abnormal operation of the diesel engine. There is currently no method for fuel viscosity calculation based on marine environment. A mathematical equation for the variation of the fuel viscosity with the temperature is therefore established through the relation between the convective heat transfer, pipe wall heat transfer, and external convective heat transfer in low sulfur oil transportation pipelines. A viscosity temperature model of the low sulfur oil pipeline system is established to study the influence of summer conditions on low sulfur oil transportation in pipelines based on the construction layout of ultra large container ship platforms and ship pipelines. The results indicate that the low sulfur fuel from the latest fuel standard can meet the requirements of viscosity at inlet of most commercial diesel engines for daily use for ultra large container ships with appropriate design and arrangement of pipelines. This calculation method can also be used to verify and estimate the viscosity and temperature changes of non-phase-change fluids under marine environments.

Marine air compressors work in a harsh environment, with multiple internal and external excitation sources. The collected noise signals are strongly time-varying, resulting in low fault diagnosis accuracy and thus difficulties in effective identification of various faults of marine air compressors. To address this problem, a fault diagnosis method combining Gramian Angular field (GAF) and Convolutional Neural Network (CNN) is proposed. Firstly, the basic principles, methods and implementation procedures of GAF and CNN are explained. Then, various faults of marine air compressors are simulated through experiments, and the noise signals of each fault are collected. The GAF is used to transform the one-dimensional time-domain signals into two-dimensional images, mapping the characteristic information to texture features such as colors and points of the two-dimensional images. Finally, the two-dimensional images are fed into CNN for feature extraction and fault diagnosis. The experimental results show that the proposed method can effectively identify various faults of the marine air compressor with a diagnostic accuracy of 99.2% superior to other algorithms, while ensuring the operational efficiency. It can provide technical references for the application of intelligent fault diagnosis systems for ships.