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.

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.

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.

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 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 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.

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 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.

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.

"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.