Ensuring the safety of ship navigation is fundamental to the high-quality development of waterway transportation. However, the complex and ever-changing nature of the navigation environment poses significant challenges to ensuring the safe passage of ships. The management of navigation safety risks is gradually shifting from passive measures, such as emergency response and post-accident analysis, to proactive risk prevention and decision-making. This paper analyses the current state of domestic and international research into the proactive control of ship navigation safety, as well as existing issues. It reviews key technologies and practical engineering applications in three areas: ship navigation information perception; ship-based navigation decision-making; and shore-based risk early warning. The paper proposes an integrated, intelligent and resilient approach to developing ship navigation safety controls, providing insights and technical references to enhance proactive control capabilities.

The upper reaches of the Yangtze River are characterized by a complex channel shape, numerous curved shoals, and significant variations in water level. The conditions for constructing the waterway are complex and changeable. In recent years, the Chinese government has increased investment in waterway construction in this area. However, the new cross-river bridges often face problems such as limited site selection, limited span and scale, a high risk of ship collision, and deteriorating navigation conditions. These issues have an irreversible impact on navigation development. Therefore, it is urgent to develop a technology to guarantee bridge navigation safety that is suitable for the complex waterway in the upper reaches of the Yangtze River. Based on the navigation conditions of complex bridges in the upper reaches of the Yangtze River, this paper proposes a safety evaluation system for full-cycle bridge navigation, analyzed in five stages: planning, design, construction, operation and demolition. This paper also proposes a key technical system for full-cycle bridge navigation safety, adapted to complex waterway bridges in mountainous areas in the upper reaches of the Yangtze River. This technology can provide guidance for navigating bridges over complex waterways in the upper reaches of the Yangtze River and is of practical significance.

To solve the problems of complex decision-making and the difficulty of global optimisation involving many factors, this paper establishes a scheduling model for maritime search and rescue forces and uses a second-generation non-dominant genetic algorithm based on a reduplication strategy (DW-NSGA-Ⅱ) to solve these problems. Firstly, the probability of a successful search and survival (POSAS) is elaborated upon, taking into account the survival probability of the target and the relevant mathematical model of the time it takes the search and rescue force to arrive at the search area. A search and rescue force dispatch model is then established with the following optimisation goals: the maximum search success rate, the shortest arrival time of search and rescue materials, and the minimum search and rescue cost. Secondly, to solve the problems of crowding, distance failure, and poor global optimisation caused by multiple repeated solutions when solving the search and rescue force scheduling model using the second-generation non-dominant genetic algorithm (NSGA-Ⅱ), a second-generation non-dominant genetic algorithm based on a reduplication strategy (DW-NSGA-Ⅱ) is proposed. Finally, an accident is used as an example to demonstrate the use of DW-NSGA-Ⅱ and NSGA-Ⅱ to solve the model, with the resulting optimisation outcomes being compared. The experimental results show that the proposed method can consider marine environmental information, accident rescue requirements and search and rescue forces to formulate a reasonable and effective search and rescue force scheduling scheme. The DW-NSGA-Ⅱ algorithm's optimisation effect is better than that of the NSGA-Ⅱ algorithm under the same initial conditions, which verifies the superiority of DW-NSGA-Ⅱ in search and rescue force dispatch.

Ocean waves are characterised as random and non-linear. Predicting significant wave height is critical for ensuring the safety of ship navigation and route planning. In the present study, the Grey Wolf optimiser was improved by optimising the search mechanism and coupled it with the Grouping Method Data Handling model to construct an effective significant wave height prediction model. This novel prediction model was validated using a significant wave height dataset. The weights of the different model variables were also explored. The results show that the IGWO-GMDH model is more accurate. The mean square error decreased by 2.65%, and the root mean square error decreased by approximately 1.35%. The standard deviation was reduced by 2.14%. Additionally, the weights of the wave characteristic parameters and the wind field data are relatively high; combining these would significantly impact the model's accuracy. The IGWO-GMDH model will provide more robust predictions of significant wave height and support research into ship navigation safety and route planning and optimisation.

In order to solve the problem of difficult control of rebound and large impact during the berthing process of vessels not under command, a variable throttling active buffer method is proposed. The principle of the variable throttling active buffer for vessels not under command has been designed. A mathematical model of the system is established. A simulation model of the system is built based on AMESim. The simulation results of the passive buffer system and the active variable throttle system are then compared. The effectiveness of the variable throttle active buffer system is verified. The main analysis focuses on the pressure in the variable throttle chamber, the displacement of the ship berthing buffer and the speed. The influence of the opening pressure of the variable throttle valve and the overflow valve on the performance of the active variable throttle buffer is studied. The results show that, when using the berthing variable throttle active buffer system, the vessel decelerates smoothly without rebound during the berthing process and there is no pressure impact or fluctuation in the variable throttle chamber. Increasing the variable throttle opening prolongs the pressure response time of the variable throttle chamber. Increasing the relief valve opening pressure prolongs the pressure attenuation time of the variable throttle chamber. Under low-normal speed or light load berthing conditions, the ship berthing buffer decelerates gently.

Qinzhou Port, one of the largest in the Beibu Gulf, had a throughput of over 170 million tonnes and a container throughput of more than 5.4 million TEUs in 2022. The port is currently considering adopting the "seamless-connection mode" scheduling strategy to improve the operational efficiency of container ships. However, quantitative analysis tools are lacking. Using AnyLogic simulation software, this study has created a simulation model of the entire process of arriving at the port, waiting at the anchorage, entering the channel, anchoring, and leaving the port, both under the 'seamless-connection mode' and the existing scheduling modes for container ships at Qinzhou Port. The simulation results show that, compared with the existing scheduling mode, the average waiting time for container ships is reduced by 50.7%, while the threshold value for harbour service ships can be increased by 19.5%. These results provide port authorities with the necessary theoretical and data-driven support to formulate relevant policies and traffic rules.

The International Association of Classification Societies has updated the North Atlantic wave scatter diagram and supplementary requirements. A series of ships, including bulk carriers, oil tankers, container ships, ore carriers, LNG carriers, PCTC ships and passenger ships, were used to analyse the influence of the updated wave scatter diagram on a ship's wave load through long-term wave load prediction. The results of the analysis show that, compared with the original North Atlantic wave scatter diagram, the new diagram and supplementary requirements have a different impact on different ship types, typically decreasing by 0~40%. The results of this study provide a reference for determining the extreme wave load of ships above the new scatter diagram.

Optimising pilot scheduling can reduce working hours and labour costs for pilots, while offering new approaches to pilot training. This paper addresses the scheduling of pilots for inbound and outbound vessels in a one-way waterway by establishing a joint optimisation model, with the aim of minimising total vessel waiting time, total pilot working hours and labour costs. It proposes a two-stage heuristic algorithm that combines an imperialist competitive algorithm, an adaptive evolutionary strategy, and a variable neighbourhood search (VNS) algorithm. Case studies and comparative experiments demonstrate the effectiveness of the model and algorithm. Compared with the traditional first-come, first-served (FCFS) rule, the proposed approach reduces pilots' average working hours and labour costs by 17.4% and 12.4%, respectively. Therefore, integrating the model and algorithm into pilot training programmes or operational guidelines could enhance coordination among port departments, improve organisational efficiency and service quality, and support the development of green and smart ports.

Inland river navigation plays an important role in supporting the domestic and international dual circulation by connecting international and domestic markets. However, the navigable channels of inland waterways are limited. With the increased demand for inland vessel traffic and higher requirements for vessel traffic services, attention is increasingly being paid to the safety and efficiency of inland vessel traffic. It is necessary to rigorously explore the regularity and characteristics of inland vessel traffic flow and conduct research into traffic efficiency, safety and available channel capacity. Traffic flow simulation is one of the key methods employed in this type of research. By investigating and analysing the navigation behaviour characteristics of inland vessels, a cellular automata-based model of vessel traffic flow in inland waterways is established, and a simulation experiment is carried out based on a straight segment of the Yangtze River. The simulation results demonstrate that the model can accurately predict vessel behaviour, such as overtaking, entering and leaving waterways. The simulated traffic flow characteristics in trajectory simulations and spatial-temporal diagrams align closely with the actual situation. These results can provide theoretical and technical support for analysing inland waterway traffic flow, supervising vessel traffic, planning waterways, and forecasting traffic flow.

This paper studied the problem of distributing commodities for RoRo ships. Taking into account the initial inventory level at each demand port, the paper proposes a flexible calling strategy for RoRo ships transporting commodity vehicles within multiple voyage planning periods. A collaborative optimization model for routing and stowage was established for RoRo ships, and an improved genetic algorithm was designed to solve it. The results of the numerical example demonstrate that this flexible calling strategy can reduce the total distribution cost of RoRo ships by 1.9%. There is a difference of about 4% in fuel consumption between large and small RoRo ships for round-trip voyages on the same route. Shipping companies can also reduce total costs by arranging different types of RoRo ship for distribution. When the safety stock is set to a moderate level, the total cost during the planning period is minimized. These research conclusions can provide a useful reference for shipping companies when making decisions about the distribution of commodities with RoRo ships.

To improve the effectiveness of Unmanned Surface Vehicle (USV) path planning in complex marine environments, and to address the issue of low operational efficiency in dynamic environments, a new Dynamic Window Approach (DWA) for USV path planning has been developed. Firstly, the target water area range is determined based on the USV's initial and target positions, and the water area is modelled using a grid system. Secondly, the forces exerted on the USV by wind, waves and currents are calculated and combined with the USV's mass to produce an acceleration value, thereby forming a kinematic model of the USV under the influence of the marine environment. Thirdly, the maximum values of linear and angular acceleration of the USV are determined using the Fossen ship dynamics model, thus obtaining the actual reachable speed set of the USV. Finally, an adaptive weight adjustment algorithm is used to improve DWA and plan the USV path, considering the heading, safe distance and speed factors. Simulation experiments were conducted in the waters near the Zhoushan Islands using the USV "Zhi Kun" to verify the reliability of the model. The results show that, compared with the comparative algorithm, the proposed algorithm performs better in terms of running time, simulation step size, change in bow direction amplitude, change in speed amplitude, and length of the planned path. The improved DWA-planned path ensures the USV can reach its destination safely and quickly, providing a reference for improving the autonomous navigation performance and efficient utilisation of USVs.

Currently, there is still no unified evaluation standard system for intelligent collision avoidance algorithms for vessels, either domestically or internationally. The development of an intelligent collision avoidance algorithm evaluation method that combines subjective and objective criteria is therefore of great significance for the realization of intelligent collision avoidance for vessels. This paper proposes a comprehensive evaluation method for the collision avoidance capability of two vessels in open water. Firstly, an algorithm evaluation system based on three core indexes of safety, compliance and economy is constructed using the reasonable quantification of the "International Regulations for Collision Avoidance at Sea" and experts' experience. Secondly, the weights of the indexes are determined using the hierarchical analysis method and the expert estimation method based on the results of the questionnaires collected, and an appropriate subordination function is established by choosing a suitable evaluation model and developing a fuzzy evaluation model for the intelligent collision avoidance algorithm. Secondly, an evaluation model and a fuzzy comprehensive evaluation system for the intelligent collision avoidance algorithm are developed. Finally, the constructed evaluation system is used to evaluate typical scenarios. The evaluation system is then used to evaluate typical scenarios. The test results demonstrate that the evaluation is fair and impartial, objectively reflecting the algorithm's strengths and weaknesses, and providing direction for improvement based on the scoring results.

The manoeuvrability of large ships is generally undesirable at their design speed, resulting in continuous risks to ship navigation safety. Meanwhile, the development of intelligent and unmanned ship design and construction brings stricter technical requirements for the safe realisation of autonomous ship navigation due to the inherent weakness in the manoeuvrability of large ships. To improve the braking performance of existing ships, the study proposes the installation of a pair of spoiler fins, the braking performance of which is investigated using real-scale CFD flow resistance analyses. Furthermore, the braking effects are simulated. The study shows that equipping large ships with properly designed spoiler fins can significantly improve their deceleration and steering performance, thereby promoting higher ship manoeuvrability and navigation safety.

In order to improve the frequency stability of the ship shore power system, an improved Virtual Synchronous Generator (VSG) control strategy is proposed. Firstly, the effects of inertia and damping on frequency are analyzed through the small-signal model of the active power of VSG. Then, based on the transient processes of active power and angular frequency, the requirements for inertia and damping in different stages of the system's non-steady state are enumerated. This analysis is used to design a control method that enables inertia and damping to be adjusted adaptively with load changes, thereby effectively suppressing the fluctuation of shore power frequency. Simulation experiments show that, compared with the traditional VSG control with constant inertia and damping, the adaptive VSG control exhibits smaller overshoot, shorter adjustment time, and better adjustment accuracy for shore power frequency regulation. This approach effectively improves the system's frequency modulation (FM) characteristics and enhances the smoothness of active power transfer from shore power to ship power.

With the increasing proportion of inland LNG fuel in the energy structure under China's "dual-carbon strategy", the consequences of LNG leakage on water surfaces have become a primary risk factor in its promotion and operational processes. While some studies have verified the validity of LNG ground leakage models, the heat exchange process between water surfaces and LNG is far more intense than on land, and its impact on leakage consequences cannot be overlooked. Based on existing research, this paper proposes a heat transfer simulation method for LNG leakage on water surfaces, integrating a multiphase flow model, turbulent diffusion model, and combustion model. Using data from large-scale LNG water leakage tests (Falcon-1 and Phoenix-1), statistical parameters such as FB, MG, VG, MRSE, NMSE, and FAC2 are employed as quantitative evaluation metrics to assess LNG leakage behavior and its effects. The results demonstrate that when simulating LNG waterborne leakage, diffusion, and combustion using this method, the quantitative evaluation indices meet the model validity criteria. This confirms that the model can effectively predict the consequences of LNG waterborne leakage, providing critical insights for policymaking related to inland waterway LNG operations and fuel safety. Thus, the model can serve as a reliable tool for future LNG waterborne leakage simulations.

"The road to water" is one of the emission reduction pathways for inland transportation. The low carbon emission reduction of the inland waterway shipping industry has received widespread attention. The carbon emission intensity index is the core issue in the process of greening the inland waterway shipping industry. Developing a prediction model for the carbon emission intensity of inland vessels is the basis for formulating new energy policies for inland shipping. This paper discusses the green transformation of the inland waterway shipping industry, drawing on cutting-edge domestic and international research. First, it analyses the factors influencing inland waterway shipping carbon emissions and their interrelationships. Based on this analysis, a system dynamics model was used to construct a prediction method for carbon emission intensity. This method was then used to analyse the changing trend of carbon emission intensity for container vessels, using the Yangtze River as a case study under various scenarios. The results show that: i. The system dynamics model for predicting carbon emission intensity in inland river operations is valid and reflects the real system more accurately. ii. Under the vessel energy efficiency improvement scenario, the carbon emission intensity decreases to 94.04% and 64.40% in 2030 and 2060 respectively, compared with the baseline scenario. iii. The carbon emission intensity in 2030 and 2060 decreases to 87.47% and 29.35% of the baseline scenario for the same year respectively when multiple measures are implemented to improve ship energy efficiency, optimise energy structure, accelerate the elimination of vessels, and levy a carbon tax.

The green development of shipping is an important foundation for the high-quality development of inland shipping. By analysing the relationship between Guangdong's economy, shipping, energy and the environment, a model of the Guangdong inland green shipping system was constructed using the system dynamics method. Scenarios were simulated and the effect of different green scenarios on the energy consumption and pollutant emissions of Guangdong inland shipping was analysed. The results show that, by 2030, reducing the energy consumption of transport vehicles will have a greater positive impact on the shipping industry than changing the energy structure. The green effect of the combined scenario was better than that of the single scenario, with an energy-saving effect of 18.25% and 36.39% respectively for the inland navigation system. The emission reduction effect was 22.42% and 50.93% respectively. Switching to low-sulphur oil for inland shipping system ships would reduce air pollutant emissions (SO₂ and NO_x) by an average of around 49 300 and 60 500 tonnes, respectively. In the long term, green development in Guangdong's inland shipping sector can be based on optimising the industrial structure and implementing various strategies, such as changing the energy structure and technical means.

To promote the green transformation of the shipping industry and improve environmental responsibility awareness among shipping enterprises, this paper presents a game model with two enterprises that differ in their awareness of environmental responsibility. The model uses non-cooperative game theory to study how environmental responsibility awareness affects investment in green shipping and the economic utility of enterprises during market competition. The results of the study show that the optimal level of investment in green shipping is determined solely by the cost-benefit analysis of the investment itself, rather than by the investment levels of other companies or the market environment. When there is a large gap in environmental responsibility awareness among shipping companies or when indirect cargo profit and loss is too low, enterprises' willingness to transform to green shipping will weaken during competition, as enterprises that take the initiative to transform to green shipping will lose their competitive advantage due to excessive encroachment on productive resources and reduced economic efficiency. Furthermore, to ensure that the overall utility of the shipping market improves with the depth of green transformation, it is necessary to control the cost of green investment, improve the return on investment of green shipping and reduce the pressure on enterprises to transform to green shipping. Based on the analysis results, it is recommended that the government promulgates policies and regulations to unify green shipping standards, encourage technological innovation in shipping and promote industry synergy and technology sharing, in order to achieve continuous green transformation.

Clean and low-carbon development in the transportation sector is crucial for preventing, controlling and mitigating atmospheric environmental problems that threaten sustainable human health. Based on statistical data, sustainable development reports and pollution prevention and control plans for the five modes of transport, including railways, highways, waterways, civil aviation and urban transport, released by the relevant authorities, we have introduced rail-water intermodal transport, China-Europe express trains, high-speed rail passenger transport, Electronic Toll Collection (ETC) and 12 strategies to improve the quality of vehicle fuel, including enhancing port efficiency and maritime energy efficiency. Ship fuel quality; pollution control and emission reduction at solid and liquid bulk cargo terminals; enhancing civil aviation's energy conservation and emission reduction capabilities; electric public transport; and rail transit. A calculation model for reducing air pollutants and greenhouse gas emissions was proposed based on the fuel method, transportation energy consumption, emission factors and alternative transportation volume. Twelve scenario emission reduction estimation methods based on analogy and statistical analysis were also proposed. Based on estimated reductions in fuel, air pollutants and CO₂, the effectiveness of clean and low-carbon development in comprehensive transportation has been reviewed since 2013. Prospects for the development of clean and low-carbon comprehensive transportation have been established in response to the problems and challenges we face.

China rivers are abundant in water resources, and inland container transport is the main form of river transport. However, with the rapid development of road construction, the continuous improvement of the comprehensive transport system and increased competition in road transportation resulting in lower freight costs, inland container transport will also face huge challenges. In order to utilise the economical and energy-saving role of inland river transport more effectively, it is necessary to encourage owners of goods to choose the waterway transportation mode. From the perspective of the inland container transport system, this paper conducts a quantitative analysis to address the issue of modal choice between inland container transport and road transport, internalising the economic externality of carbon emission through the total cost of transport. Taking into account the low-carbon objective, a transportation mode choice equilibrium model based on an inland container transport system was constructed. Meanwhile, the paper focuses on analysing the economic characteristics of total transportation costs and related influencing factors using an economic approach. Finally, the model's validity is verified using numerical examples. The results demonstrate that, under the low-carbon objective, it is more economical for owners to choose waterway transportation when the transportation distance is more than 1 100 km.

The coastal engineering of the port area is special and complex due to the terrain of the water and land. The manned measurement ship was unable to enter the test area and some areas limit the UAV. This paper presents an integrated measurement method that combines unmanned ship sounding with 3D laser scanning. Its practical application in Guangxi Port Area coastal engineering shows that measurement data fusion control and point cloud integration technology can safely and efficiently obtain high-density point cloud data across the entire survey area. The accuracy of the results meets the operational specifications' requirements and can serve as a reference for comprehensive survey technology applications in coastal engineering.

As the CII regulations took effect in 2023, shipping companies are under increasing pressure to comply with these stringent regulations. This paper presents a fleet optimization method for CII regulatory constraints, considering the difference in main engine fuel consumption performance within the fleet. Two scenarios are optimized: "Fleet scheduling considering single ship CII rating limits" and "Fleet scheduling with no E-class ships and the least used biofuel". The results demonstrate that the proposed optimization algorithm outperforms random scheduling in maintaining fleet CII compliance and reducing biofuel usage. This study will help shipping companies meet fleet CII regulations and reduce carbon emissions, while improving their ability to respond to international green and low-carbon regulations.