Journal of Marine Science and Engineering

18 pages, 1032 KB

Open AccessArticle

Modeling Growth, Mortality, and Detachment of Sessile Marine Organisms: An Integrated DEB-Statistical Approach

by Teng Tu, Jinxin Zhou, Daisuke Kitazawa, Akane Takahashi, Yoshinobu Yoneyama and Masanobu Hasebe

J. Mar. Sci. Eng. 2025, 13(10), 1858; https://doi.org/10.3390/jmse13101858 - 25 Sep 2025

Abstract

Sessile marine organisms form the foundation of many coastal ecosystems, playing crucial roles in functions like water filtration and habitat provision. Understanding their population dynamics—particularly the interplay of growth, reproduction, and detachment under environmental stress—is essential for both ecological research and effective coastal [...] Read more.

Sessile marine organisms form the foundation of many coastal ecosystems, playing crucial roles in functions like water filtration and habitat provision. Understanding their population dynamics—particularly the interplay of growth, reproduction, and detachment under environmental stress—is essential for both ecological research and effective coastal management. This work presents a comprehensive numerical model for simulating the growth, reproduction, mortality and detachment of sessile organisms using a hybrid dynamic energy budget (DEB)–statistical approach. Our model incorporates bioenergetic processes, environmental stress responses, space competition, and layering dynamics. The simulation framework considers the effects of temperature, salinity, dissolved oxygen, and food availability on organism physiology while tracking growth, reproduction, and mortality and detachment. Model validation was performed using field data collected from sessile invertebrate populations around a floating platform in the estuary of the Sumida River in Tokyo, Japan, from September 2002 to September 2003. Our approach successfully reproduced observed patterns with high accuracy. The model revealed that temperature stress and salinity fluctuations interact synergistically, amplifying mortality and detachment rates beyond what would be predicted by each factor independently. Comparative analyses with reduced models lacking either mortality or detachment components demonstrated the importance of including both processes for the accurate prediction of population dynamics. Our case study provides a robust framework for predicting sessile organism responses to environmental variability and highlights key areas for future research in benthic ecosystem modeling. Full article

(This article belongs to the Section Marine Biology)

17 pages, 8174 KB

Open AccessArticle

Calculation and Analysis of Rolling Hydrodynamic Coefficients of Free-Flooding Ship Based on STAR-CCM+

by Chaofan Li, Yuehu Teng, Min Xu and Renchuan Zhu

J. Mar. Sci. Eng. 2025, 13(10), 1857; https://doi.org/10.3390/jmse13101857 (registering DOI) - 25 Sep 2025

Abstract

As free-flooding ships are a type of vessel with openings on their hull surfaces, accurately calculating and analyzing their roll hydrodynamic coefficients is of great significance for ship motion prediction. Based on the STAR CCM+ platform that employs the computational fluid dynamics (CFD) [...] Read more.

As free-flooding ships are a type of vessel with openings on their hull surfaces, accurately calculating and analyzing their roll hydrodynamic coefficients is of great significance for ship motion prediction. Based on the STAR CCM+ platform that employs the computational fluid dynamics (CFD) method, this paper first conducts numerical simulations of the forced roll motion of a damaged DTMB-5415 ship model. The applicability of this method to side-opening ship types is verified by comparing with experimental results. Subsequently, this numerical method is applied to simulate the forced roll of a free-flooding aquaculture ship under different working conditions, and the roll hydrodynamic coefficients of its hull and internal compartments are calculated and analyzed. The roll hydrodynamic coefficients of the intact ship and the free-flooding ship are compared. The results indicate the characteristics of roll hydrodynamic coefficients of free-flooding ships, and this research will facilitate the prediction of roll motion for this ship type. Full article

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

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18 pages, 1135 KB

Open AccessArticle

Acoustic Scattering Characteristics of Micropterus salmoides Using a Combined Kirchhoff Ray-Mode Model and In Situ Measurements

by Wenzhuo Wang, Meiping Sheng, Zhiwei Guo and Minqing Wang

J. Mar. Sci. Eng. 2025, 13(10), 1856; https://doi.org/10.3390/jmse13101856 - 25 Sep 2025

Abstract

Effective management of Micropterus salmoides resources requires accurate assessment of their abundance and distribution. Fisheries acoustics is a key method for such evaluations, yet its application is limited by insufficient target strength (TS) data. This study combines the Sobel edge detection [...] Read more.

Effective management of Micropterus salmoides resources requires accurate assessment of their abundance and distribution. Fisheries acoustics is a key method for such evaluations, yet its application is limited by insufficient target strength (TS) data. This study combines the Sobel edge detection technique with the Kirchhoff ray-mode model to estimate the TS of Micropterus salmoides cultured in Guangdong, China, and validates the results through in situ measurements. The relationships between TS and fish body length were established at 38 kHz, 70 kHz, 120 kHz, and 200 kHz. At 200 kHz, the average in situ TS was –42.41 dB, with a fitted formula of TS = 32.00 lgL–88.24. Further validation was performed using time- and frequency-domain analyses of echo signals. The results show that TS increases with swim bladder volume, indicating its dominant influence. The relationship between TS and frequency is nonlinear and affected by the swim bladder angle, swimming posture, and behavioral patterns. This study also improves the computational efficiency of the Kirchhoff ray-mode model. Overall, it provides essential parameters for acoustic stock assessment of Micropterus salmoides, providing a scientific basis for their sustainable management and conservation. Full article

(This article belongs to the Section Marine Aquaculture)

44 pages, 3365 KB

Open AccessReview

Inductive Wireless Power Transfer for Autonomous Underwater Vehicles: A Comprehensive Review of Technological Advances and Challenges

by Han Xu, Rong Zheng, Bo Yang and Wei Ning

J. Mar. Sci. Eng. 2025, 13(10), 1855; https://doi.org/10.3390/jmse13101855 - 25 Sep 2025

Abstract

The endurance of autonomous underwater vehicles (AUVs) has long been constrained by limited energy replenishment. Underwater inductive wireless power transfer (UIWPT), with its contactless power transfer capability, offers an innovative solution for efficient underwater charging of AUVs. This paper provides a systematic review [...] Read more.

The endurance of autonomous underwater vehicles (AUVs) has long been constrained by limited energy replenishment. Underwater inductive wireless power transfer (UIWPT), with its contactless power transfer capability, offers an innovative solution for efficient underwater charging of AUVs. This paper provides a systematic review of the architecture of UIWPT systems, analyzes key power loss mechanisms and corresponding optimization strategies, and summarizes the latest research progress in magnetic coupler design, compensation circuit topologies, control methods, simultaneous power and data transfer, and seawater-induced eddy current losses. Representative cases of UIWPT system integration on AUV platforms are also reviewed, with particular emphasis on environmental factors such as salinity variation, biofouling, and deep-sea pressure, as well as EMC, which critically constrain engineering applications. Finally, this paper discusses development trends including high-efficiency power transfer, enhanced reliability under extreme environments, and practical deployment challenges, and it presents a forward-looking technical roadmap towards long-term, autonomous, and intelligent underwater wireless power transfer. Full article

(This article belongs to the Special Issue Advances in Recent Marine Engineering Technology)

26 pages, 3429 KB

Open AccessArticle

I-VoxICP: A Fast Point Cloud Registration Method for Unmanned Surface Vessels

by Qianfeng Jing, Mingwang Bai, Yong Yin and Dongdong Guo

J. Mar. Sci. Eng. 2025, 13(10), 1854; https://doi.org/10.3390/jmse13101854 - 25 Sep 2025

Abstract

The accurate positioning and state estimation of surface vessels are prerequisites to autonomous navigation. Recently, the rapid development of 3D LiDARs has promoted the autonomy of both land and aerial vehicles, which has attracted the interest of researchers in the maritime community. However, [...] Read more.

The accurate positioning and state estimation of surface vessels are prerequisites to autonomous navigation. Recently, the rapid development of 3D LiDARs has promoted the autonomy of both land and aerial vehicles, which has attracted the interest of researchers in the maritime community. However, in traditional maritime surface multi-scenario applications, LiDAR scan matching has low point cloud scanning and matching efficiency and insufficient positional accuracy when dealing with large-scale point clouds, so it has difficulty meeting the real-time demand of low-computing-power platforms. In this paper, we use ICP-SVD for point cloud alignment in the Stanford dataset and outdoor dock scenarios and propose an optimization scheme (iVox + ICP-SVD) that incorporates the voxel structure iVox. Experiments show that the average search time of iVox is 72.23% and 96.8% higher than that of ikd-tree and kd-tree, respectively. Executed on an NVIDIA Jetson Nano (four ARM Cortex-A57 cores @ 1.43 GHz) the algorithm processes 18 k downsampled points in 56 ms on average and 65 ms in the worst case—i.e., ≤15 Hz—so every scan is completed before the next 10–20 Hz LiDAR sweep arrives. During a 73 min continuous harbor trial the CPU temperature stabilized at 68 °C without thermal throttling, confirming that the reported latency is a sustainable, field-proven upper bound rather than a laboratory best case. This dramatically improves the retrieval efficiency while effectively maintaining the matching accuracy. As a result, the overall alignment process is significantly accelerated, providing an efficient and reliable solution for real-time point cloud processing. Full article

(This article belongs to the Special Issue Unmanned Surface Vessels (USVs): Technology, Applications and Regulatory Landscapes)

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13 pages, 2151 KB

Open AccessArticle

Low-Phase-Error Underwater Acoustic Spiral Wavefront Array and Phase Error Compensation

by Rongzhen Guo, Wei Lu and Yu Lan

J. Mar. Sci. Eng. 2025, 13(10), 1853; https://doi.org/10.3390/jmse13101853 - 24 Sep 2025

Abstract

Acoustic spiral wavefronts demonstrate linear phase directionality, facilitating precise azimuth estimation in underwater navigation through phase comparison with reference wavefronts characterized by constant phase directionality. The reliability of azimuth estimation depends on the phase directionality accuracy of both the spiral and reference wavefront [...] Read more.

Acoustic spiral wavefronts demonstrate linear phase directionality, facilitating precise azimuth estimation in underwater navigation through phase comparison with reference wavefronts characterized by constant phase directionality. The reliability of azimuth estimation depends on the phase directionality accuracy of both the spiral and reference wavefront sources. This study introduces a seven-element transmitting array, constructed using bender disk transducers, which is capable of generating both spiral and reference acoustic wavefronts with minimal phase directionality error. The array design was developed and evaluated using a point source array model and numerical simulations, followed by physical fabrication. To address the sensitivity of the phase–azimuth linearity to manufacturing imperfections in sound sources, a phase error compensation technique was implemented by adjusting the input signal parameters to the acoustic emitters. Experimental validation was conducted in an anechoic water tank, where both spiral and reference wavefronts were transmitted across multiple frequencies. The results reveal that the array prototype achieved sub-degree-level compensated phase directionality accuracy for both wavefront types at all the tested frequencies. Notably, at the resonance frequency of 7.3 kHz, the root-mean-square phase directionality error of the spiral wavefront was reduced to as low as 0.19°. Full article

(This article belongs to the Special Issue Advances in Underwater Positioning and Navigation Technology)

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25 pages, 958 KB

Open AccessReview

Survey on Multi-Source Data Based Application and Exploitation Toward Smart Ship Navigation

by Xuhong Tang, Jie Zhou, Shengjie Hou, Yang Sun and Kai Luo

J. Mar. Sci. Eng. 2025, 13(10), 1852; https://doi.org/10.3390/jmse13101852 - 24 Sep 2025

Abstract

Maritime ship transportation is not only the core infrastructure of the global logistics system but also is closely related to national security and sustainable development. However, the human factor remains the primary source of risk leading to maritime accidents during ship navigation. In [...] Read more.

Maritime ship transportation is not only the core infrastructure of the global logistics system but also is closely related to national security and sustainable development. However, the human factor remains the primary source of risk leading to maritime accidents during ship navigation. In recent years, multi-source data has been recognized as an important means to improve the efficiency of ship operations and navigation safety. In this paper, the major research methods and technical pathways of maritime multi-source data in recent years have been systematically reviewed, and a comprehensive technical framework from data acquisition and preprocessing to practical application has been constructed. Focusing on the data layer, application layer, and system layer, this paper comprehensively analyzes the key technologies of maritime navigation based on multi-source data. At the same time, this paper also highlights the advantages and cutting-edge methods of multi-source data in typical application scenarios—such as track extraction, target recognition, behavior detection, path planning, and collision avoidance—and analyzes their performance and adaptation strategies in different usage contexts. Through the combination of theory and engineering practice, this paper looks forward to the future development of ship intelligence and water transportation systems, providing a theoretical basis and technical support for the construction of intelligent shipping systems. Full article

(This article belongs to the Section Ocean Engineering)

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19 pages, 6598 KB

Open AccessArticle

Parametric Study on the Near-Wall Wake Flow of a Circular Cylinder: Influence of Gap Ratio and Reynolds Number

by Changjing Fu, Shunxin Yang and Tianlong Zhao

J. Mar. Sci. Eng. 2025, 13(10), 1851; https://doi.org/10.3390/jmse13101851 - 24 Sep 2025

Abstract

Near-wall flow around circular cylinders is commonly encountered in various engineering applications, such as submarine pipelines and river-crossing conduits. The wake structure significantly influences local flow stability and has become a critical focus in fluid dynamics research. Specifically, when the gap ratio ( [...] Read more.

Near-wall flow around circular cylinders is commonly encountered in various engineering applications, such as submarine pipelines and river-crossing conduits. The wake structure significantly influences local flow stability and has become a critical focus in fluid dynamics research. Specifically, when the gap ratio (G/D) ranges from 0.1 to 1.0, the interaction mechanism between the wall and the wake structure remains poorly understood. Moreover, the combined effects of the Reynolds number (Re) and gap ratio on the flow field require further investigation. In this study, a series of experimental measurements were conducted using two-dimensional, two-component particle image velocimetry (2D–2C PIV) to examine the influence of G/D and Re on the near-wall wake characteristics. The results indicate that, at a gap ratio of G/D = 0.1, the gap flow exhibits pronounced curling into the recirculation region, where the lower vortex is entrained and actively participates in wake evolution. When G/D ≥ 0.3, an increase in Re leads to a reduction in the lengths of both the upper and lower shear layers, a delayed attenuation of the wall-side shear layer, and a gradual symmetrization and contraction of the recirculation region behind the cylinder. Further analysis reveals that the evolution of the secondary vortex is strongly influenced by the combined effects of Re and G/D. Specifically, at Re = 3300 and G/D ≤ 0.3, the secondary vortex migrates away from the wall toward the upper shear layer, where it merges with the upper vortex. For 0.5 ≤ G/D ≤ 0.7, it interacts with the lower vortex, while at G/D = 1.0, it evolves independently downstream along the wall. At G/D = 0.5, the secondary vortex merges with the upper vortex at Re = 1100, whereas at Re = 5500, it interacts with the lower vortex instead. These findings contribute to a deeper understanding of the complex flow structures associated with near-wall cylinder wakes and offer valuable theoretical insights for engineering applications involving submarine pipelines in bottom-mounted or partially suspended configurations. Full article

(This article belongs to the Section Ocean Engineering)

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25 pages, 9227 KB

Open AccessArticle

Influence of Marine Environmental Factors on Characteristics of Composite Magnetic Field of Underwater Vehicles

by Honglei Wang, Xinyu Dong and Yixin Yang

J. Mar. Sci. Eng. 2025, 13(10), 1850; https://doi.org/10.3390/jmse13101850 - 24 Sep 2025

Abstract

This research study investigated the composite magnetic fields of underwater vehicles in the presence of ocean waves under varying conductivity, analyzed their spatiotemporal characteristics, attenuation laws, and influence mechanism. We integrated the modeling of three types of magnetic fields to obtain a composite [...] Read more.

This research study investigated the composite magnetic fields of underwater vehicles in the presence of ocean waves under varying conductivity, analyzed their spatiotemporal characteristics, attenuation laws, and influence mechanism. We integrated the modeling of three types of magnetic fields to obtain a composite magnetic field: the magnetic anomaly field generated by a ferromagnetic vehicle was simulated with a hybrid ellipsoid–dipole model, the wake magnetic field generated by its motion, and the ocean wave magnetic field generated by wind-driven waves were derived from the velocity fields. Simulation results show that the magnetic anomaly and wake magnetic fields are mainly influenced by vehicle speed, course, and diving depth, while the ocean wave magnetic field is affected by wind speed and direction. The composite magnetic field’s intensity increases with vehicle and wind speed but decreases with the increase in diving depth. This study offers a comprehensive analysis of the composite magnetic fields of underwater vehicles in the presence of ocean waves, emphasizing the significant impact of vehicle motion and marine environmental parameters. These insights are essential to gaining a deeper understanding of the magnetic fields generated by underwater vehicles as they navigate ocean waves. Full article

(This article belongs to the Section Ocean Engineering)

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28 pages, 1622 KB

Open AccessArticle

Vessel Arrival Priority Determination in VTS Management: A Dynamic Scoring Approach Integrating Expert Knowledge

by Gil-Ho Shin and Chae-Uk Song

J. Mar. Sci. Eng. 2025, 13(10), 1849; https://doi.org/10.3390/jmse13101849 - 24 Sep 2025

Abstract

Vessel arrival priority determination is a critical factor affecting port safety and efficiency in maritime traffic management, yet existing approaches relying on First Come, First Served (FCFS) principles or empirical judgment have limitations in systematic decision-making. This study aims to develop a systematic [...] Read more.

Vessel arrival priority determination is a critical factor affecting port safety and efficiency in maritime traffic management, yet existing approaches relying on First Come, First Served (FCFS) principles or empirical judgment have limitations in systematic decision-making. This study aims to develop a systematic decision-making framework that overcomes these limitations by creating an automated, expert knowledge-based priority determination system for vessel traffic services. A dynamic score-based vessel arrival priority determination model was developed integrating the Delphi technique and Fuzzy Analytic Hierarchy Process (Fuzzy AHP). Basic score evaluation factors were derived through Delphi surveys conducted with 50 field experts, and weights were calculated by differentially applying Fuzzy AHP and conventional AHP according to hierarchical complexity. The proposed model consists of a dynamic scoring system integrating basic scores reflecting vessel characteristics and operational conditions, special situation scores considering emergency situations, and risk scores quantifying safety intervals between vessels. To validate the model performance, simulation-based evaluation with eight scenarios was conducted targeting experienced VTS (Vessel Traffic Services) officers, demonstrating strong agreement with expert judgment across diverse operational conditions. The developed algorithm processes real-time maritime traffic data to dynamically calculate priorities, providing port managers and maritime authorities with an automated decision support tool that enhances VTS management and coastal traffic operations. Full article

(This article belongs to the Section Ocean Engineering)

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20 pages, 3476 KB

Open AccessArticle

A Quantitative Evaluation Method for Navigation Safety in Coastal Waters Based on Unstructured Grids

by Panpan Zhang, Jinqiang Bi, Xin Teng and Kexin Bao

J. Mar. Sci. Eng. 2025, 13(10), 1848; https://doi.org/10.3390/jmse13101848 - 24 Sep 2025

Abstract

In this paper, we propose a quantitative evaluation method for navigation safety in coastal waters based on unstructured grids. Initially, a comprehensive analysis was conducted on various factors affecting navigation safety, including natural conditions, traffic conditions, and marine hydro-meteorological conditions, to construct a [...] Read more.

In this paper, we propose a quantitative evaluation method for navigation safety in coastal waters based on unstructured grids. Initially, a comprehensive analysis was conducted on various factors affecting navigation safety, including natural conditions, traffic conditions, and marine hydro-meteorological conditions, to construct a multi-source fused spatiotemporal dataset. Subsequently, channel boundary extraction was performed using Constrained Delaunay Triangle–Alpha-Shapes, and the precise extraction of ship navigation areas was performed based on Constrained Delaunay Triangle–Voronoi diagrams. Additionally, temporal feature grids were constructed based on the spatiotemporal characteristics of marine hydro-meteorological data. Finally, unstructured grids for evaluating navigation safety were established through spatial overlay analysis. Based on this foundation, a quantitative analysis and evaluation model for comprehensive navigation safety assessment was developed using the fuzzy evaluation method. By calculating the fuzzy relation matrix and weight vectors, quantitative assessments were conducted for each grid cell, yielding safety risk levels from both spatial and temporal dimensions. An analysis was performed using maritime data within the geographic boundaries of lon.119.17–120.41° E and lat.34.40–35.47° N. The results indicated that the unstructured grid division and channel boundary extraction in the demonstrated sea area were closely related to parameters such as the ship traffic flow patterns and the spatiotemporal characteristics of the marine environmental factors. A quantitative evaluation and analysis of the 186 unstructured grid cells revealed that the high risk levels primarily corresponded to restricted navigation areas, the higher-risk grid cells were mainly anchorages, and the low to lower risk levels were primarily associated with channels and navigable areas for ships. Full article

(This article belongs to the Special Issue Advancements in Maritime Safety and Risk Assessment)

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23 pages, 17670 KB

Open AccessArticle

UWS-YOLO: Advancing Underwater Sonar Object Detection via Transfer Learning and Orthogonal-Snake Convolution Mechanisms

by Liang Zhao, Xu Ren, Lulu Fu, Qing Yun and Jiarun Yang

J. Mar. Sci. Eng. 2025, 13(10), 1847; https://doi.org/10.3390/jmse13101847 - 24 Sep 2025

Abstract

Accurate and efficient detection of underwater targets in sonar imagery is critical for applications such as marine exploration, infrastructure inspection, and autonomous navigation. However, sonar-based object detection remains challenging due to low resolution, high noise, cluttered backgrounds, and the scarcity of annotated data. [...] Read more.

Accurate and efficient detection of underwater targets in sonar imagery is critical for applications such as marine exploration, infrastructure inspection, and autonomous navigation. However, sonar-based object detection remains challenging due to low resolution, high noise, cluttered backgrounds, and the scarcity of annotated data. To address these issues, we propose UWS-YOLO, a novel detection framework specifically designed for underwater sonar images. The model integrates three key innovations: (1) a C2F-Ortho module that enhances multi-scale feature representation through orthogonal channel attention, improving sensitivity to small and low-contrast targets; (2) a DySnConv module that employs Dynamic Snake Convolution to adaptively capture elongated and irregular structures such as pipelines and cables; and (3) a cross-modal transfer learning strategy that pre-trains on large-scale optical underwater imagery before fine-tuning on sonar data, effectively mitigating overfitting and bridging the modality gap. Extensive evaluations on real-world sonar datasets demonstrate that UWS-YOLO achieves a mAP@0.5 of 87.1%, outperforming the YOLOv8n baseline by 3.5% and seven state-of-the-art detectors in accuracy while maintaining real-time performance at 158 FPS with only 8.8 GFLOPs. The framework exhibits strong generalization across datasets, robustness to noise, and computational efficiency on embedded devices, confirming its suitability for deployment in resource-constrained underwater environments. Full article

(This article belongs to the Section Ocean Engineering)

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16 pages, 4567 KB

Open AccessArticle

Influence of Sea Level Rise on Tidal Waves of the Yangtze River Estuary

by Kai Yu, Wei Ding, Yunlin Ni, Wei Chen, Mingtao Jiang and Zili Dai

J. Mar. Sci. Eng. 2025, 13(10), 1846; https://doi.org/10.3390/jmse13101846 - 24 Sep 2025

Abstract

In order to study the influence of sea level rise (SLR) on tidal wave in tidal reach, a hydrodynamic numerical model of the Yangtze River Estuary was established using MIKE 21. The verified model was used to simulate tidal wave changes from Wuhu [...] Read more.

In order to study the influence of sea level rise (SLR) on tidal wave in tidal reach, a hydrodynamic numerical model of the Yangtze River Estuary was established using MIKE 21. The verified model was used to simulate tidal wave changes from Wuhu to the estuary under SLR scenarios of 0.5 m, 1.0 m, and 2.0 m. The results show the following: (1) The impact of SLR on water level within the tidal reach can be divided into two segments: from the estuary to approximately 35 km upstream of Xuliujing and from there further upstream to the tidal limit. (2) The average water level increase is less than the magnitude of SLR. The attenuation depends on both river discharge and location within the reach; higher river discharge and increasing proximity to inland areas reduce the influence of SLR. (3) Water level fluctuation amplitude increases with SLR, showing minimal sensitivity to river discharge within the estuarine section but significant sensitivity to discharge fluctuations in the upstream section. Finally, tidal current velocity generally increases in response to SLR, with the spatial extent of the increase controlled by river discharge. Full article

(This article belongs to the Special Issue Advances in Marine Engineering: Geological Environment and Hazards—3rd Edition)

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18 pages, 3597 KB

Open AccessArticle

A Pipeline Hoop Stress Measurement Method Based on Propagation Path Correction of LCR Waves

by Bing Chen, Binbin Wang, Feifei Qiu, Chunlang Luo, Jiakai Chen and Guoqing Gou

J. Mar. Sci. Eng. 2025, 13(10), 1845; https://doi.org/10.3390/jmse13101845 - 24 Sep 2025

Abstract

Pipelines are extensively used in offshore equipment. Accurate and non-destructive measurement of hoop stress conditions within pipes is critical for ensuring the integrity of offshore structures. However, the existing technology to measure the hoop stress of the pipeline needs to planarize the surface [...] Read more.

Pipelines are extensively used in offshore equipment. Accurate and non-destructive measurement of hoop stress conditions within pipes is critical for ensuring the integrity of offshore structures. However, the existing technology to measure the hoop stress of the pipeline needs to planarize the surface of the pipeline, which greatly limits the detection efficiency. This study proposes a method for pipeline hoop stress measurement using a planar longitudinal critically refracted (LCR) probe, based on correcting LCR wave-propagation paths, which solves the problem of pipeline planarization in pipeline hoop stress measurement. First, a linear relationship between stress variations and ultrasonic time-of-flight changes in the material was established based on the acoustoelastic effect. Finite element analysis was then used to construct an acoustic simulation model for the hoop direction of the pipeline. Simulation results showed that LCR waves propagated within a wedge as quasi-plane waves and, upon oblique incidence into the pipeline, traveled along the chordal direction. Furthermore, using ray tracing methods, a mapping relationship between the pipeline geometry and the ultrasonic propagation path was established. Based on this, the LCR pipeline hoop stress measurement (LCR-HS) method was proposed. Finally, a C-shaped ring was employed to verify the measurement accuracy of the LCR-HS method. Experimental results indicated that the measurement error decreased with increasing pipe diameter and fell below 8% when the diameter exceeded 400 mm. This method enables precise measurement of hoop stress on curved surfaces by revealing the hoop propagation behavior of LCR waves in pipelines. The findings provide a technical reference for evaluating pipeline stress states, which is of significant importance for assessment of pipeline integrity. Full article

(This article belongs to the Special Issue Offshore Pipes and Energy Equipment)

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18 pages, 6741 KB

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 - 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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24 pages, 6747 KB

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 - 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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38 pages, 5218 KB

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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22 pages, 5038 KB

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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30 pages, 3003 KB

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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Journal of Marine Science and Engineering

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