Journal of Marine Science and Engineering

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Open AccessArticle

Revealing Sea-Level Dynamics Driven by El Niño–Southern Oscillation: A Hybrid Local Mean Decomposition–Wavelet Framework for Multi-Scale Analysis

by Xilong Yuan, Shijian Zhou, Fengwei Wang and Huan Wu

J. Mar. Sci. Eng. 2025, 13(10), 1844; https://doi.org/10.3390/jmse13101844 (registering DOI) - 24 Sep 2025

Abstract

Analysis of global mean sea-level (GMSL) variations provides insights into their spatial and temporal characteristics. To analyze the sea-level cycle and its correlation with the El Niño–Southern Oscillation (ENSO, represented by the Oceanic Niño Index), this study proposes an enhanced analytical framework integrating [...] Read more.

Analysis of global mean sea-level (GMSL) variations provides insights into their spatial and temporal characteristics. To analyze the sea-level cycle and its correlation with the El Niño–Southern Oscillation (ENSO, represented by the Oceanic Niño Index), this study proposes an enhanced analytical framework integrating Local Mean Decomposition with an improved wavelet thresholding technique and wavelet transform. The GMSL time series (January 1993 to July 2020) underwent multi-scale decomposition and noise reduction using Local Mean Decomposition combined with improved wavelet thresholding. Subsequently, the Morlet continuous wavelet transform was applied to analyze the signal characteristics of both GMSL and the Oceanic Niño Index. Finally, cross-wavelet transform and wavelet coherence analyses were employed to investigate their correlation and phase relationships. Key findings include the following: (1) Persistent intra-annual variability (8–16-month cycles) dominates the GMSL signal, superimposed by interannual fluctuations (4–8-month cycles) related to climatic and seasonal forcing. (2) Phase analysis reveals that GMSL generally leads the Oceanic Niño Index during El Niño events but lags during La Niña events. (3) Strong El Niño episodes (May 1997 to May 1998 and October 2014 to April 2016) resulted in substantial net GMSL increases (+7 mm and +6 mm) and significant peak anomalies (+8 mm and +10 mm). (4) Pronounced negative peak anomalies occur during La Niña events, though prolonged events are often masked by the long-term sea-level rise trend, whereas shorter events exhibit clearly discernible and rapid GMSL decline. The results demonstrate that the proposed framework effectively elucidates the multi-scale coupling between ENSO and sea-level variations, underscoring its value for refining the understanding and prediction of climate-driven sea-level changes. Full article

(This article belongs to the Special Issue Sea Level Changes: Advances in Observation Techniques, Modeling, and Understanding of Causes and Impacts)

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Open AccessArticle

YOLOv11-MSE: A Multi-Scale Dilated Attention-Enhanced Lightweight Network for Efficient Real-Time Underwater Target Detection

by Zhenfeng Ye, Xing Peng, Dingkang Li and Feng Shi

J. Mar. Sci. Eng. 2025, 13(10), 1843; https://doi.org/10.3390/jmse13101843 (registering DOI) - 23 Sep 2025

Abstract

Underwater target detection is a critical technology for marine resource management and ecological protection, but its performance is often limited by complex underwater environments, including optical attenuation, scattering, and dense distributions of small targets. Existing methods have significant limitations in feature extraction efficiency, [...] Read more.

Underwater target detection is a critical technology for marine resource management and ecological protection, but its performance is often limited by complex underwater environments, including optical attenuation, scattering, and dense distributions of small targets. Existing methods have significant limitations in feature extraction efficiency, robustness in class-imbalanced scenarios, and computational complexity. To address these challenges, this study proposes a lightweight adaptive detection model, YOLOv11-MSE, which optimizes underwater detection performance through three core innovations. First, a multi-scale dilated attention (MSDA) mechanism is embedded into the backbone network to dynamically capture multi-scale contextual features while suppressing background noise. Second, a Slim-Neck architecture based on GSConv and VoV-GSCSPC modules is designed to achieve efficient feature fusion via hybrid convolution strategies, significantly reducing model complexity. Finally, an efficient multi-scale attention (EMA) module is introduced in the detection head to reinforce key feature representations and suppress environmental noise through cross-dimensional interactions. Experiments on the underwater detection dataset (UDD) demonstrate that YOLOv11-MSE outperforms the baseline model YOLOv11, achieving a 9.67% improvement in detection precision and a 3.45% increase in mean average precision (mAP50) while reducing computational complexity by 6.57%. Ablation studies further validate the synergistic optimization effects of each module, particularly in class-imbalanced scenarios where detection precision for rare categories (e.g., scallops) is significantly enhanced, with precision and mAP50 improving by 60.62% and 10.16%, respectively. This model provides an efficient solution for edge computing scenarios, such as underwater robots and ecological monitoring, through its lightweight design and high underwater target detection capability. Full article

(This article belongs to the Section Ocean Engineering)

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Open AccessArticle

Improved YOLO-Based Corrosion Detection and Coating Performance Evaluation Under Marine Exposure in Zhoushan, China

by Qifeng Yu, Yudong Han, Xukun Huang and Xinjia Gao

J. Mar. Sci. Eng. 2025, 13(10), 1842; https://doi.org/10.3390/jmse13101842 - 23 Sep 2025

Abstract

In response to the challenges of metal corrosion detection and anti-corrosion coating performance evaluation in the marine environment of Zhoushan, this study proposes an improved object detection model, YOLO v5-EfficientViT-NWD-CCA, to enhance the recognition accuracy and detection efficiency of corrosion images on marine [...] Read more.

In response to the challenges of metal corrosion detection and anti-corrosion coating performance evaluation in the marine environment of Zhoushan, this study proposes an improved object detection model, YOLO v5-EfficientViT-NWD-CCA, to enhance the recognition accuracy and detection efficiency of corrosion images on marine structures. Based on YOLO v5, the model incorporates the EfficientViT backbone network, NWD (Normalized Wasserstein Distance) loss function, and CCA (Criss-Cross Attention) attention mechanism, outperforming comparative models across multiple key metrics. Experimental results show that the proposed model increases precision from 0.73 to 0.76 (approximately 4% improvement) and raises the True Positive rate from 0.66 to 0.70 (approximately 6% improvement) according to the confusion matrix, demonstrating more stable overall detection performance. Building on this, the study combines the model’s detection results to conduct a quantitative analysis of the corrosion area of eight types of anti-corrosion coatings in two typical marine environments—tidal zones and fully immersed zones—across different exposure periods (24, 60, and 96 months). The results indicate that the tidal zone presents a harsher corrosion environment, with corrosion severity significantly increasing over time. Fusion-bonded epoxy coatings, powder epoxy coatings, and fluorocarbon coatings exhibit good corrosion resistance, whereas chlorinated rubber coatings and conventional epoxy coatings perform poorly. This study not only achieves intelligent identification and precise quantification of corrosion areas but also provides a scientific basis for the selection and evaluation of anti-corrosion coatings in different marine environments. Full article

(This article belongs to the Special Issue Advanced Research on the Sustainable Maritime Transportation (2nd Edition))

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Open AccessArticle

Numerical Investigation of Flow Field Characteristics Around a Monopile Foundation with Collar Protection

by Lei Wu, Hao Meng, Haifei Sun, Lingfei Yu, Dake Chen, Xiyu Zhao and Dawei Guan

J. Mar. Sci. Eng. 2025, 13(10), 1841; https://doi.org/10.3390/jmse13101841 - 23 Sep 2025

Abstract

Collar structures are widely used to protect monopile foundations from scour, but their geometric obstruction hinders direct observation of the surrounding flow in physical experiments. To overcome this limitation, this study employs large-eddy simulation (LES) to investigate the flow characteristics around a monopile [...] Read more.

Collar structures are widely used to protect monopile foundations from scour, but their geometric obstruction hinders direct observation of the surrounding flow in physical experiments. To overcome this limitation, this study employs large-eddy simulation (LES) to investigate the flow characteristics around a monopile with collar protection. The LES model was validated against well-documented experimental data of pile-induced flow, confirming its reliability. Simulations under flat-bed and equilibrium scour conditions were conducted to evaluate the effects of the collar on time-averaged velocity, vortex dynamics, and turbulence intensity. The results show that the collar substantially weakens the upstream accelerated flow, suppresses horseshoe vortex formation, and reduces both the strength and extent of sidewall currents. Under flatbed conditions, the side-flow intensity decreases by 24.3% and the accelerated flow area is reduced by 93.3%. A counter-rotating vortex beneath the collar dissipates kinetic energy and simplifies the near-bed vortex system, thereby mitigating scour. However, the protective effect diminishes with increasing inflow velocity, with turbulence intensity rising by 159% for a 14% velocity increase. Overall, this study provides deeper insights into the protective mechanisms of collar structures, advancing the understanding of their effectiveness and limitations in monopile scour protection. Full article

(This article belongs to the Special Issue Advancements in Marine Hydrodynamics and Structural Optimization)

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Open AccessArticle

Integrated Scheduling of Handling and Spraying Operations in Smart Coal Ports: A MAPPO-Driven Adaptive Micro-Evolutionary Algorithm Framework

by Yidi Wu, Shiwei He, Haozhou Tang, Zeyu Long and Aibing Xiang

J. Mar. Sci. Eng. 2025, 13(10), 1840; https://doi.org/10.3390/jmse13101840 - 23 Sep 2025

Abstract

This study explores the integrated scheduling optimization of coal port operations, addressing the dual challenges of handling efficiency and resource conservation by coordinating equipment scheduling with stockyard spraying operations. Through a systematic analysis of operational processes in coal ports, a mixed-integer linear programming [...] Read more.

This study explores the integrated scheduling optimization of coal port operations, addressing the dual challenges of handling efficiency and resource conservation by coordinating equipment scheduling with stockyard spraying operations. Through a systematic analysis of operational processes in coal ports, a mixed-integer linear programming (MILP) model is developed to achieve global optimization while explicitly quantifying water and electricity consumption in spraying operations. To address this complex problem, we propose a novel hybrid algorithm that integrates a micro-evolutionary algorithm (MEA) framework with multi-agent proximal policy optimization (MAPPO), enabling adaptive decision-making for large-scale real-time scheduling. Three specialized agents for crossover, mutation, and neighborhood search achieve collaborative optimization by observing population features as states, selecting evolutionary operators as actions, and receiving composite rewards based on both population improvement and individual contributions. This strategy facilitates adaptive operator selection and optimal evolutionary direction derivation, collectively guiding population evolution toward high-quality solutions. Extensive experiments on ten scaled instances of a real-world coal port confirm the proposed algorithm’s superior performance. Compared with four other standard algorithms, it consistently yields higher hypervolume (HV) values and lower inverted generational distance (IGD) metrics, which collectively demonstrate stronger convergence capability and higher solution quality. Full article

(This article belongs to the Special Issue Sustainable and Efficient Maritime Operations)

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Open AccessArticle

Data-Driven Load Suppression and Platform Motion Optimization for Semi-Submersible Wind Turbines

by Liqing Liao, Qian Huang, Li Wang, Jian Yang, Dongran Song, Sifan Chen and Lingxiang Huang

J. Mar. Sci. Eng. 2025, 13(10), 1839; https://doi.org/10.3390/jmse13101839 - 23 Sep 2025

Abstract

To address the issues of large fatigue loads on key components and poor platform motion stability under the coupling effect of wind, waves, and internal excitations in semi-submersible wind turbines, this paper proposes a data-driven load suppression and platform motion optimization method. First, [...] Read more.

To address the issues of large fatigue loads on key components and poor platform motion stability under the coupling effect of wind, waves, and internal excitations in semi-submersible wind turbines, this paper proposes a data-driven load suppression and platform motion optimization method. First, the NREL 5 MW OC4 semi-submersible wind turbine is used as the research object. Wind-wave environment and aeroelastic simulation models are constructed based on TurbSim and OpenFAST. The rainflow counting method and Palmgren–Miner rule are applied to calculate the damage equivalent load (DEL) of key components, and the platform’s maximum horizontal displacement (Smax) is defined to represent the motion range. Secondly, a systematic analysis is conducted to examine the effects of servo control variables such as generator speed, yaw angle, and active power on the DELs of the blade root, tower base, drivetrain, mooring cables, and platform Smax. It is found that the generator speed and the yaw angle have significant impacts, with the DELs of the blade root and drivetrain showing a strong positive correlation with Smax. On this basis, a fatigue load model based on random forests is established. A multi-objective optimization framework is built using the NSGA-II algorithm, with the objectives of minimizing the total DEL of key components and Smax, thereby optimizing the servo control parameters. Case studies based on actual marine environmental data from the East China Sea show that, compared to the baseline configuration (a typical unoptimized control strategy), the optimization results lead to a maximum reduction of 14.1% in the total DEL of key components and a maximum reduction of 16.95% in Smax. The study verifies the effectiveness of data-driven modeling and multi-objective optimization for coordinated control, providing technical support for improving the structural safety and operational stability of semi-submersible wind turbines. Full article

(This article belongs to the Special Issue Cutting-Edge Technologies in Offshore Wind Energy)

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Open AccessArticle

Nonlinear-Finite-Time-Extended-State-Observer-Based Command Filtered Control for Unmanned Surface Vessels with Rotatable Thrusters under False Data Injection Attacks

by Mengwei Chen, Guichen Zhang and Xiangfei Meng

J. Mar. Sci. Eng. 2025, 13(10), 1838; https://doi.org/10.3390/jmse13101838 - 23 Sep 2025

Abstract

Considering the importance of maritime cybersecurity, this study provides a solution based on a nonlinear finite-time extended state observer (NFTESO) for unmanned surface vessels (USVs) equipped with rotatable thrusters under false data injection attacks (FDIAs). First, to complete the control design for USVs [...] Read more.

Considering the importance of maritime cybersecurity, this study provides a solution based on a nonlinear finite-time extended state observer (NFTESO) for unmanned surface vessels (USVs) equipped with rotatable thrusters under false data injection attacks (FDIAs). First, to complete the control design for USVs in a network environment and ensure optimal tracking performance within limits, an event triggering mechanism with finite-time constraints and a concise control optimization framework are employed. Then, command filtered technology is applied to obtain the derivative of the virtual control quantity generated using a backstepping design, optimizing the information interaction process in the kinematic and dynamic loops. The design based on the NFTESO estimates the composite uncertain dynamics in the system, including FDIAs, reducing the adverse effects of cyber attacks on the system. Finally, simulation outcomes confirmed the efficacy of the proposed control strategy. The simulation results showed that, compared with two other control schemes, the control scheme designed in this paper improved lateral tracking accuracy by approximately

77.1 %

and

94.7 %

, and longitudinal tracking accuracy by approximately

95 %

and

98 %

, respectively. Communication frequency was reduced by approximately

98.82 %

and

82.48 %

, respectively. Full article

(This article belongs to the Section Ocean Engineering)

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Open AccessArticle

Spatiotemporal Dynamics and Drivers of Wetland Change on Chongming Island (2000–2020) Using Deep Learning and Remote Sensing

by An Yi, Yang Yu, Hua Fang, Jiajun Feng and Jinlin Ji

J. Mar. Sci. Eng. 2025, 13(10), 1837; https://doi.org/10.3390/jmse13101837 - 23 Sep 2025

Abstract

Using Landsat series imagery and the deep learning model CITNet, this study conducted high-accuracy classification and spatiotemporal change analysis of wetlands on Chongming Island from 2000–2020 and explored the driving mechanisms by integrating climatic and anthropogenic factors. The results demonstrate that the total [...] Read more.

Using Landsat series imagery and the deep learning model CITNet, this study conducted high-accuracy classification and spatiotemporal change analysis of wetlands on Chongming Island from 2000–2020 and explored the driving mechanisms by integrating climatic and anthropogenic factors. The results demonstrate that the total wetland area decreased by approximately 125.5 km² over the two decades. Among natural wetlands, tidal mudflats and shallow seawater zones continuously shrank, while herbaceous marshes exhibited a “decline recovery” trajectory. Artificial wetlands expanded before 2005 but contracted significantly thereafter, mainly due to aquaculture pond reduction. Wetland transformation was dominated by wetland-to-non-wetland conversions, peaking during 2005–2010. Driving factor analysis revealed a “human pressure dominated, climate modulated” pattern: nighttime light index (NTL) and GDP demonstrated strong negative correlations with wetland extent, while minimum temperature and the Palmer Drought Severity Index (PDSI) promoted herbaceous marsh expansion and accelerated artificial wetland contraction, respectively. The findings indicate that wetland changes on Chongming Island result from the combined effects of policy, economic growth, and ecological processes. Sustainable management should focus on restricting urban expansion in ecologically sensitive zones, optimizing water resource allocation under drought conditions, and incorporating climate adaptation and invasive species control into restoration programs to maintain both the extent and ecological quality of wetlands. Full article

(This article belongs to the Section Coastal Engineering)

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Open AccessArticle

Coupled Vibration Response Analysis of Tension Leg Platform Tendon Under Irregular Ocean Wave Action

by Qiangqiang Wu, Yinguang Du, Xiaofeng Luo, Tao Sun and Heng Lin

J. Mar. Sci. Eng. 2025, 13(10), 1836; https://doi.org/10.3390/jmse13101836 - 23 Sep 2025

Abstract

To analyze the dynamic response of tension leg platform (TLP) tendons under irregular ocean wave action, the governing equations of coupled vibration between the platform and tendon under irregular wave action are established based on Hamilton’s principle and the Kirchhoff hypothesis. Using the [...] Read more.

To analyze the dynamic response of tension leg platform (TLP) tendons under irregular ocean wave action, the governing equations of coupled vibration between the platform and tendon under irregular wave action are established based on Hamilton’s principle and the Kirchhoff hypothesis. Using the spectrum representation–random function method, the power spectral density function of the irregular wave load is derived, and the lateral wave forces at different tendon locations are calculated. The coupled lateral and axial responses of the tendon system are obtained through the fourth-order Runge–Kutta method. Considering the parametric vibrations of both the platform and tendon, the extreme lateral deflection of the tendon is employed as the control index to derive the probability density curves of the tendon deflection under irregular wave load. The results show that the amplitude of the wave load increases gradually along the height of the tendon, with a faster growth rate at locations closer to the water surface. The tendon’s lateral deflection response changes more drastically due to coupled parametric vibration of the platform. Based on 628 complete samples of irregular wave loads, the probability density curve and cumulative distribution curve of the extreme lateral deflection of the tendon under irregular wave loads are obtained. Under typical sea state conditions generated from the P-M wave spectrum, the reliability of the tendon under irregular wave load increases with the initial tension force. Full article

(This article belongs to the Special Issue Advanced Studies in Marine Structures)

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Open AccessArticle

Optimized Line-of-Sight Active Disturbance Rejection Control for Depth Tracking of Hybrid Underwater Gliders in Disturbed Environments

by Yan Zhao, Hefeng Zhou, Pan Xu, Yongping Jin, Zhangfu Tian and Yun Zhao

J. Mar. Sci. Eng. 2025, 13(10), 1835; https://doi.org/10.3390/jmse13101835 - 23 Sep 2025

Abstract

Hybrid underwater gliders (HUGs) combine buoyancy-driven gliding with propeller-assisted propulsion, offering extended endurance and enhanced mobility for complex underwater missions. However, precise depth control remains challenging due to system uncertainties, environmental disturbances, and inadequate adaptability of conventional control methods. This study proposes a [...] Read more.

Hybrid underwater gliders (HUGs) combine buoyancy-driven gliding with propeller-assisted propulsion, offering extended endurance and enhanced mobility for complex underwater missions. However, precise depth control remains challenging due to system uncertainties, environmental disturbances, and inadequate adaptability of conventional control methods. This study proposes a novel optimized line-of-sight active disturbance rejection control (OLOS-ADRC) strategy for HUG depth tracking in the vertical plane. First, an Optimized Line-of-Sight (OLOS) guidance dynamically adjusts the look-ahead distance based on real-time cross-track error and velocity, mitigating error accumulation during path following. Second, a Tangent Sigmoid-based Tracking Differentiator (TSTD) enhances the disturbance estimation capability of the Extended State Observer (ESO) within the Active Disturbance Rejection Control (ADRC) framework, improving robustness against unmodeled dynamics and ocean currents. As a critical step before costly sea trials, this study establishes a high-fidelity simulation environment to validate the proposed method. The comparative experiments under gliding and hybrid propulsion modes demonstrated that OLOS-ADRC has significant advantages: the root mean square error (RMSE) for depth tracking was reduced by 83% compared to traditional ADRC, the root mean square error for pitch angle was decreased by 32%, and the stabilization time was shortened by 14%. This method effectively handles ocean current interference through real-time disturbance compensation, providing a reliable solution for high-precision HUG motion control. The simulation results provide a convincing foundation for future field validation in oceanic environments. Despite these improvements, the study is limited to vertical plane control and simulations; future work will involve full ocean trials and 3D path tracking. Full article

(This article belongs to the Section Ocean Engineering)

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20 pages, 3689 KB

Open AccessArticle

A Robust Two-Dimensional Shallow Flow Model with Adaptive Quadtree Mesh

by Gangfeng Wu, Zhiyuan Li and Haoxuan Weng

J. Mar. Sci. Eng. 2025, 13(10), 1834; https://doi.org/10.3390/jmse13101834 - 23 Sep 2025

Abstract

A two-dimensional shallow flow model is developed by integrating a positivity-preserving, well-balanced central-upwind scheme with a block-structured quadtree AMR grid implemented in the Afivo open-source framework. A non-negative water depth reconstruction ensures second-order spatial accuracy and the robust treatment of wetting and drying, [...] Read more.

A two-dimensional shallow flow model is developed by integrating a positivity-preserving, well-balanced central-upwind scheme with a block-structured quadtree AMR grid implemented in the Afivo open-source framework. A non-negative water depth reconstruction ensures second-order spatial accuracy and the robust treatment of wetting and drying, while coarse-grid fluxes at refinement boundaries are obtained by summing the corresponding fine-grid fluxes, thereby guaranteeing strict mass conservation between refinement levels. Mesh refinement is driven by gradients in water surface elevation, which focus resolution on regions of rapid flow variation, thereby improving both accuracy and computational efficiency. Model validation through benchmark problems and the Malpasset dam-break event show close agreement with analytical solutions, laboratory measurements, and previous numerical simulations, while achieving substantial reductions in computational cost. Full article

(This article belongs to the Section Ocean Engineering)

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22 pages, 883 KB

Open AccessArticle

Development of a Model for Increasing the Capacity of Small and Medium-Sized Ports Using the Principles of Probability Theory

by Vytautas Paulauskas, Donatas Paulauskas and Vytas Paulauskas

J. Mar. Sci. Eng. 2025, 13(9), 1833; https://doi.org/10.3390/jmse13091833 - 22 Sep 2025

Abstract

Every year, more and more general and other types of cargo are transported by containers, and many ports, including small and medium-sized ones, are trying to join the container transportation processes. Port connectivity with container shipping is associated with easier and faster cargo [...] Read more.

Every year, more and more general and other types of cargo are transported by containers, and many ports, including small and medium-sized ones, are trying to join the container transportation processes. Port connectivity with container shipping is associated with easier and faster cargo processing and reduced environmental impact by optimizing ship arrivals and processing in small and medium-sized ports. Small and medium-sized ports are often limited by port infrastructure, especially suitable quays; therefore, it is very important to correctly assess the capabilities of such ports so that ships do not have to wait for entry and so that quays and other port infrastructure are optimally used. The research is relevant because small and medium-sized ports are increasingly involved in the activities of logistics chains and are becoming very important for the development of individual regions. The wider use of small and medium-sized ports in logistics chains is a new and original research direction. Optimal assessment of port or terminal and berth utilization is possible using the principles of probability theory. The article develops and presents a probabilistic method for assessment of port and terminal and ship mooring at their berths, using possible and actual time periods, based on the principles of transport process organization and linked to the capabilities of the port infrastructure and terminal superstructure. The conditional probability method was used to assess port and terminal capacity, as well as a method for assessing ship maneuverability under limited conditions. The developed probabilistic method for assessing port terminals and ship berthing at port quays can be used in any port or terminal, taking into account local conditions. Combined theoretical research and experimental results of the optimal use of small and medium-sized ports ensure sufficient research quality. Full article

(This article belongs to the Special Issue Smart Seaport and Maritime Transport Management, Second Edition)

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27 pages, 4021 KB

Open AccessArticle

Research on Water Surface Object Detection Method Based on Image Fusion

by Yihong Chen, Xiaoyi Ma, Qi Wang, Yunqian He and Shuo Xie

J. Mar. Sci. Eng. 2025, 13(9), 1832; https://doi.org/10.3390/jmse13091832 - 22 Sep 2025

Abstract

Accurate and rapid detection of surface targets is a key technology for autonomous navigation of intelligent and unmanned ships. Faced with complex maritime environments and ever-changing maritime targets, it is impossible to consistently obtain accurate target detection results based on a single sensor. [...] Read more.

Accurate and rapid detection of surface targets is a key technology for autonomous navigation of intelligent and unmanned ships. Faced with complex maritime environments and ever-changing maritime targets, it is impossible to consistently obtain accurate target detection results based on a single sensor. Infrared and visible light have strong complementarity. By fusing infrared and visible images, a more comprehensive and prominent fused image can be obtained, effectively improving the accuracy of target detection. This article constructs a lightweight convolutional neural network image fusion model based on the fusion framework of convolutional neural networks and then uses the constructed water surface dataset for comprehensive experimental testing of image fusion and object detection. The test results show that the object detection model trained using fused images has better detection performance than the object detection model trained using infrared and visible light images alone. So, integrating two types of images can provide better results for object detection and help promote the development of related technologies. Full article

(This article belongs to the Special Issue The Control and Navigation of Autonomous Surface Vehicles)

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17 pages, 4602 KB

Open AccessArticle

Typhoon-Induced Wave–Current Coupling Dynamics in Intertidal Zones: Impacts on Protective Device of Ancient Forest Relics

by Lihong Zhao, Dele Guo, Chaoyang Li, Zhengfeng Bi, Yi Hu, Hongqin Liu and Tongju Han

J. Mar. Sci. Eng. 2025, 13(9), 1831; https://doi.org/10.3390/jmse13091831 - 22 Sep 2025

Abstract

Extreme weather events, such as typhoons, induce strong wave–current interactions that significantly alter nearshore hydrodynamic conditions, particularly in shallow intertidal zones. This study investigates the influence of wind speed and water depth on wave–current coupling under typhoon conditions in Shenhu Bay, southeastern China—a [...] Read more.

Extreme weather events, such as typhoons, induce strong wave–current interactions that significantly alter nearshore hydrodynamic conditions, particularly in shallow intertidal zones. This study investigates the influence of wind speed and water depth on wave–current coupling under typhoon conditions in Shenhu Bay, southeastern China—a semi-enclosed bay that hosts multiple ancient forest relics within its intertidal zone. A two-tier numerical modeling framework was developed, comprising a regional-scale hydrodynamic model and a localized high-resolution model centered on a protective structure. Validation data were obtained from in situ field observations. Three structural scenarios were tested: fully intact, bottom-blocked, and damaged. Results indicate that wave-induced radiation stress plays a dominant role in enhancing flow velocities when wind speeds exceed 6 m/s, with wave contributions approaching 100% across all water depths. However, the linear relationship between water depth and wave contribution observed under non-typhoon conditions breaks down under typhoon forcing. A critical depth range was identified, within which wave contribution peaked before declining with further increases in depth—highlighting its potential sensitivity to storm energy. Moreover, structural simulations revealed that bottom-blocked devices, although seemingly more enclosed, may be vulnerable to vertical pressure loading due to insufficient water exchange. In contrast, perforated designs facilitate an internal–external hydrodynamic balance, thereby enhancing protective effect. This study provides both theoretical and practical insights into intertidal structure design and paleo-heritage conservation under extreme hydrodynamic stress. Full article

(This article belongs to the Special Issue Advances in Storm Tide and Wave Simulations and Assessment)

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26 pages, 1624 KB

Open AccessArticle

Design of an Observing System Simulation Experiment for the Operational Model of the Southwestern Coast of Iberia (SOMA)

by Fernando Mendonça, Flávio Martins and Laurent Bertino

J. Mar. Sci. Eng. 2025, 13(9), 1830; https://doi.org/10.3390/jmse13091830 - 21 Sep 2025

Abstract

Observing System Simulation Experiments (OSSEs) provide a framework in which to evaluate the impact of prospective ocean-observation networks on model forecasting performance prior to their actual deployment. This study presents the design and validation of an OSSE tailored for the operational coastal model [...] Read more.

Observing System Simulation Experiments (OSSEs) provide a framework in which to evaluate the impact of prospective ocean-observation networks on model forecasting performance prior to their actual deployment. This study presents the design and validation of an OSSE tailored for the operational coastal model of southern Portugal, SOMA. The system adopts the fraternal twins approach and a univariate data-assimilation scheme based on Ensemble Optimal Interpolation to update the model’s 3D temperature structure with SST. The methodology provides a flexible framework that preserves the statistical structure of real observation errors while remaining independent of SOMA. This allows straightforward transfer to other applications, thereby broadening its applicability and making it useful as a starting point in the design of observation networks beyond that presented in this case study. The OSSE experiments were compared against corresponding Observing System Experiments (OSEs) using real satellite SST products. Results show that the designed OSSE is internally consistent, sensitive to observation density, and capable of reproducing realistic correction patterns that closely match those obtained in the OSEs. These findings provide strong evidence that the SOMA OSSE system is a reliable tool for assessing the potential impact of future surface-observation strategies. Full article

(This article belongs to the Special Issue Monitoring of Ocean Surface Currents and Circulation)

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23 pages, 12444 KB

Open AccessArticle

Dynamic Responses and Damage Assessment of Submerged Floating Tunnel Under Explosive Loads

by Xiangji Ye, Ming Wang, Dongsheng Qiao, Xin Zhao and Li Wang

J. Mar. Sci. Eng. 2025, 13(9), 1829; https://doi.org/10.3390/jmse13091829 - 21 Sep 2025

Abstract

Submerged floating tunnel (SFT) may be subjected to sudden explosive loads such as internal vehicle explosions, terrorist attacks, and external explosions during operation. Based on the Arbitrary Lagrange–Euler (ALE) method, the locally truncated SFT model and fluid–structure interaction model of internal air and [...] Read more.

Submerged floating tunnel (SFT) may be subjected to sudden explosive loads such as internal vehicle explosions, terrorist attacks, and external explosions during operation. Based on the Arbitrary Lagrange–Euler (ALE) method, the locally truncated SFT model and fluid–structure interaction model of internal air and external water are established. Spherical explosives are used to simulate the destructive impact of internal explosions at different positions of the road inside the SFT and key positions at the bottom of the road. The results show that the peak accelerations at the monitoring points caused by the explosions of vehicles on the road rapidly decay within a range of three times the radius of the SFT, and circularly distributed damage appears on the explosion-facing side of the road surface. Longitudinal extensional damage occurs at the junction of the road surface and the SFT wall as well as the bottom supporting wall. Longitudinal cracks appear on the SFT wall. The peak accelerations at the monitoring points of the internal road caused by the concealed bomb at the bottom of the SFT rapidly decay within a range of twice the radius of the SFT, and the damage to the SFT is mainly concentrated on the road surface and the supporting wall. The most dangerous direction of external underwater explosion is determined to be directly below the SFT. When the scaled distance of the explosion is less than 0.543 m/kg^1/3, the accelerations at the monitoring points of the internal road show a single-peak trend with rapid rise and decay, and circumferential through-cracks appear on the SFT wall. The supporting wall connecting the SFT wall and the internal road transmits stress to the road, causing extensive damage. Full article

(This article belongs to the Section Ocean Engineering)

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15 pages, 1108 KB

Open AccessArticle

A Novel Displacement Prediction Model for Inclined Anchor Bolt Based on Mindlin’s Solution

by Zhenhua Zhang, Guojuan Xu and Banglu Xi

J. Mar. Sci. Eng. 2025, 13(9), 1828; https://doi.org/10.3390/jmse13091828 - 21 Sep 2025

Abstract

Since anchoring technology is a key measure to enhance the deformation resistance of engineering structures, it is widely applied in bridges, dams, power transmission lines, and offshore platforms. The displacement of anchor bolts directly affects the deformation resistance of structures, and anchor bolts [...] Read more.

Since anchoring technology is a key measure to enhance the deformation resistance of engineering structures, it is widely applied in bridges, dams, power transmission lines, and offshore platforms. The displacement of anchor bolts directly affects the deformation resistance of structures, and anchor bolts are frequently arranged at an inclination angle in engineering practice—this inclination angle significantly affects their displacement. However, existing anchor bolt displacement prediction models do not account for the influence of inclination angles. To address this gap, a novel displacement prediction model for inclined anchor bolts based on Mindlin’s solution is proposed in this paper. The validation with three experimental datasets shows that the model’s relative errors are within 5%. Even if minor measurement uncertainties regarding input parameters exist in practical engineering scenarios, the calculated displacement results will not undergo significant deviations. The anchor bolt displacement prediction model proposed in this paper may help scholars better understand the relationship between anchor bolt inclination angle and displacement. Full article

(This article belongs to the Section Ocean Engineering)

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22 pages, 9764 KB

Open AccessArticle

Modelling of the Present Oceanographic Situation of the Gulfs of Patras and Corinth

by Basile Caterina, Aurélia Hubert-Ferrari, Alexander Barth and Jean-Marie Beckers

J. Mar. Sci. Eng. 2025, 13(9), 1827; https://doi.org/10.3390/jmse13091827 - 21 Sep 2025

Abstract

In our study we investigated the hydrodynamic circulation of the Gulfs of Patras and Corinth through modelling. To this end, ROMS was used to numerically calculate the parameters of the waters for these peculiar semi-enclosed basins. Several oceanographic forcings were used with an [...] Read more.

In our study we investigated the hydrodynamic circulation of the Gulfs of Patras and Corinth through modelling. To this end, ROMS was used to numerically calculate the parameters of the waters for these peculiar semi-enclosed basins. Several oceanographic forcings were used with an emphasis on the tides and the winds. With several simulations, each focusing on a specific element, we were able to describe more accurately the dynamics under the surface to complete what was previously done. The high velocity currents (0.6 m/s at the Patraic end of the strait) were validated through ADCP and satellite data, proving that modelling can be trusted to fill the gap in the in situ data over these two gulfs. Our simulations, mainly based on the month of May 2023, allowed us to understand the importance of the tides, especially in the Rio–Antirio Strait. There, the bottom currents are the strongest while the center of the Corinthian Gulf remains quiet. The surface dynamics were observed to be sensitive to the tides, the winds and the season, but general patterns were still highlighted for the oceanographic circulation of the gulfs. Full article

(This article belongs to the Section Physical Oceanography)

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32 pages, 4858 KB

Open AccessArticle

A Hierarchical Slip-Compensated Control Strategy for Trajectory Tracking of Wheeled ROVs on Complex Deep-Sea Terrains

by Dewei Li, Zizhong Zheng, Yuqi Wang, Zhongjun Ding, Yifan Yang and Lei Yang

J. Mar. Sci. Eng. 2025, 13(9), 1826; https://doi.org/10.3390/jmse13091826 - 20 Sep 2025

Abstract

With the rapid development of deep-sea resource exploration and marine scientific research, wheeled remotely operated vehicles (ROVs) have become crucial for seabed operations. However, under complex seabed conditions, traditional ROV control systems suffer from insufficient trajectory tracking accuracy, poor disturbance rejection capability, and [...] Read more.

With the rapid development of deep-sea resource exploration and marine scientific research, wheeled remotely operated vehicles (ROVs) have become crucial for seabed operations. However, under complex seabed conditions, traditional ROV control systems suffer from insufficient trajectory tracking accuracy, poor disturbance rejection capability, and low dynamic torque distribution efficiency. These issues lead to poor motion stability and high energy consumption on sloped terrains and soft substrates, which limits the effectiveness of deep-sea engineering. To address this, we proposed a comprehensive motion control solution for deep-sea wheeled ROVs. To improve modeling accuracy, a coupled kinematic and dynamic model was developed, together with a body-to-terrain coordinate frame transformation. Based on rigid-body kinematics, three-degree-of-freedom kinematic equations incorporating the slip ratio and sideslip angle were derived. By integrating hydrodynamic effects, seabed reaction forces, the Janosi soil model, and the impact of subsidence depth, a dynamic model that reflects nonlinear wheel–seabed interactions was established. For optimizing disturbance rejection and trajectory tracking, a hierarchical control method was designed. At the kinematic level, an improved model predictive control framework with terminal constraints and quadratic programming was adopted. At the dynamic level, non-singular fast terminal sliding mode control combined with a fixed-time nonlinear observer enabled rapid disturbance estimation. Additionally, a dynamic torque distribution algorithm enhanced traction performance and trajectory tracking accuracy. Full article

(This article belongs to the Section Ocean Engineering)

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Journal of Marine Science and Engineering

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