Journal of Marine Science and Engineering

25 pages, 25309 KB

Open AccessArticle

Experimental Study of the Angle of Repose of Coral Sands

by Zhen Yao, Jie Chen, Changbo Jiang, Zhiyuan Wu, Bin Deng, Yuannan Long, Hongtao Zou, Jinwei Zhang and Runze Bai

J. Mar. Sci. Eng. 2025, 13(12), 2410; https://doi.org/10.3390/jmse13122410 - 18 Dec 2025

Viewed by 211

Abstract

The angle of repose is a fundamental parameter for assessing the stability of coral reefs. However, predictive models for this angle are currently lacking. In this study, a series of laboratory experiments were undertaken to investigate the angle of repose by varying moisture [...] Read more.

The angle of repose is a fundamental parameter for assessing the stability of coral reefs. However, predictive models for this angle are currently lacking. In this study, a series of laboratory experiments were undertaken to investigate the angle of repose by varying moisture content, particle shape, and particle size. Based on our experimental data, variation in the angle of repose with moisture content is classified into five distinct zones. It is demonstrated that the range of moisture content for each zone varies with particle size. Coral sands of dendrite, flake, rod, and block particles have a descending order of angle of repose, as demonstrated for a sieve size of 4.5 mm. The angle of repose for dry, submerged, and steady coral sands exhibits a correlation with the nominal diameter of particle size. Finally, extended models are proposed for predicting the angle of repose of coral sands (R² = 0.8, D_n₅₀ = 0.317−5.470). To facilitate use of these models, a linear relationship between sieve particle size diameter, nominal particle size diameter, and Corey shape factor, allowing for conversion among these parameters, is established. This study thereby helps to enhance our understanding of how moisture content affects angle of repose and improve our ability to predict the angle for coral grains with intricate geometries. Full article

(This article belongs to the Section Ocean Engineering)

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21 pages, 10472 KB

Open AccessArticle

The Influence of Submesoscale Motions on Upper-Ocean Chlorophyll: Case of Benguela Current Large Marine Ecosystem (BCLME)

by Ekoué Ewane Blaise Arnold, Richard Kindong, Ebango Ngando Narcisse, Pandong Njomoue Achile and Song Hu

J. Mar. Sci. Eng. 2025, 13(12), 2409; https://doi.org/10.3390/jmse13122409 - 18 Dec 2025

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Abstract

Submesoscale dynamics are critical modulators of upper-ocean biogeochemistry, yet their net influence on chlorophyll concentrations across seasonal to interannual timescales, particularly within productive regions like the Benguela Current Large Marine Ecosystem (BCLME), remains poorly understood. This study quantifies these complex relationships by analyzing [...] Read more.

Submesoscale dynamics are critical modulators of upper-ocean biogeochemistry, yet their net influence on chlorophyll concentrations across seasonal to interannual timescales, particularly within productive regions like the Benguela Current Large Marine Ecosystem (BCLME), remains poorly understood. This study quantifies these complex relationships by analyzing 22 years (2001–2022) of physical and biological data. We examined the link between surface chlorophyll (CHL) and key physical drivers: sea level anomaly (SLA) and submesoscale intensity, quantified by the Rossby number (Ro). Using both cross-correlation analysis and Generalized Linear Models (GLMs), our analyses reveal a multi-scale set of spatially dependent and time-lagged biogeochemical responses. At the basin scale, a key finding from cross-correlation is a significant positive correlation where high SLA precedes a rise in CHL by approximately six months, indicating a delayed ecosystem response to large-scale physical forcing. At the event scale, GLMs show the specific impact of eddies is critical: short-lived cyclonic eddies correlate with a significant increase in CHL (~4.6%) in the southern zone, while anticyclonic eddies are associated with a pronounced decrease in CHL (~97.7%) in the central zone during the austral winter. These findings demonstrate that both large-scale preconditions and localized submesoscale features are essential drivers of vertical nutrient transport and the distribution of primary productivity within the BCLME. Full article

(This article belongs to the Section Physical Oceanography)

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24 pages, 5574 KB

Open AccessArticle

Linking Shoreline Change, Environmental Forcings, and Sedimentological Resilience in Nourished Beaches of Cape May and Wildwood, New Jersey, USA: A Multi-Decadal Synthesis

by Divomi Balasuriya and Greg Pope

J. Mar. Sci. Eng. 2025, 13(12), 2408; https://doi.org/10.3390/jmse13122408 - 18 Dec 2025

Viewed by 191

Abstract

Beach nourishment is a widely used strategy to mitigate coastal erosion, yet its long-term geological impacts remain poorly understood. This study provides a multi-decadal synthesis of shoreline change and sedimentological evolution on the nourished beaches of Cape May and Wildwood, New Jersey, USA. [...] Read more.

Beach nourishment is a widely used strategy to mitigate coastal erosion, yet its long-term geological impacts remain poorly understood. This study provides a multi-decadal synthesis of shoreline change and sedimentological evolution on the nourished beaches of Cape May and Wildwood, New Jersey, USA. Using shoreline positions from 1991 to 2024, we identify contrasting trajectories: Wildwood exhibits ‘persistent transition’ with severe northern erosion (EPR: −10.0 m/yr) feeding southwards accretion, while Cape May demonstrates a ‘managed equilibrium’ with widespread accretion (mean EPR: +1.15 m/yr). Wave energy correlations account for less than 15% of shoreline variability, indicating natural drivers have been superseded by human sediment inputs. Direct sediment comparison shows substantial textural transformation, with median grain sizes increasing from 153 to 435 μm to 467–982 μm and sorting degrading from very well to moderately well sorted, reflecting sustained disequilibrium. These findings are synthesized into a conceptual model where nourishment initiates feedback cycles that create human-dependent morphodynamic trajectories. This study concludes that the long-term resilience of developed coasts will depend on a strategic evolution from managing ‘sand as volume’ toward stewarding ‘sediment as a system,’ where textural compatibility is a primary determinant of success. Full article

(This article belongs to the Section Marine Environmental Science)

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24 pages, 6057 KB

Open AccessArticle

Numerical Analysis Comparison Between ANSYS AQWA and OrcaFlex for a Hollow Box-Shaped Floating Structure

by Se Hwan Park, Sang Gyu Cheon and Woo Chul Chung

J. Mar. Sci. Eng. 2025, 13(12), 2407; https://doi.org/10.3390/jmse13122407 - 18 Dec 2025

Viewed by 461

Abstract

This study presents a numerical comparison between ANSYS AQWA (2023 R2) and the OrcaFlex package (OrcaWave + OrcaFlex) for a 10 × 10 × 2 m rectangular floating structure. The hydrodynamic coefficients and displacement/load RAOs obtained from the two solvers exhibit nearly identical [...] Read more.

This study presents a numerical comparison between ANSYS AQWA (2023 R2) and the OrcaFlex package (OrcaWave + OrcaFlex) for a 10 × 10 × 2 m rectangular floating structure. The hydrodynamic coefficients and displacement/load RAOs obtained from the two solvers exhibit nearly identical behavior, with deviations below 1% across all six motion modes. Under irregular wave conditions (Hs = 7 m, Tp = 8 s, 0° heading) and three mooring line lengths (145, 150, and 155 m), both solvers produced comparable mean surge motions and mean mooring tensions. However, OrcaFlex predicted 40–50% higher peak tensions due to its fully dynamic representation of slack–taut transitions and snap loading effects, whereas AQWA’s quasi-static catenary formulation filtered out these short-duration peaks. These findings confirm that although the two solvers are highly consistent in frequency-domain hydrodynamics, their time-domain predictions diverge when nonlinear mooring behavior becomes dominant. The study provides a transparent and reproducible benchmarking framework for cross-validation of potential-flow-based tools used in floating offshore structure design. Full article

(This article belongs to the Special Issue Autonomous Ship and Harbor Maneuvering: Modeling and Control)

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17 pages, 3125 KB

Open AccessArticle

Improve Initial Field Estimation with Deep Learning in Data Assimilation for Climate Models

by Jiakuan Wang, Liang Zhang, Yi Lin and Xuefeng Zhang

J. Mar. Sci. Eng. 2025, 13(12), 2406; https://doi.org/10.3390/jmse13122406 - 18 Dec 2025

Viewed by 318

Abstract

In marine and coastal climate prediction, the integration of multiple imperfect models can improve accuracy by leveraging their complementary strengths. This study investigates this potential by developing a hybrid data assimilation framework that couples a biased physical model with a deep learning model. [...] Read more.

In marine and coastal climate prediction, the integration of multiple imperfect models can improve accuracy by leveraging their complementary strengths. This study investigates this potential by developing a hybrid data assimilation framework that couples a biased physical model with a deep learning model. A neural network learns an optimal fitting coefficient to weight the contributions of both models throughout the assimilation process. We evaluated the framework in twin experiments based on a five-variable coupled climate model and a trained LSTM. Evaluations using root-mean-square error, frequency histograms, and probability density functions consistently demonstrated that the multi-model synthesis achieves superior assimilation performance compared to the single-model approach. Furthermore, when employing different analysis values for prediction, the overall prediction error of the multi-model coupled scheme is reduced to approximately 50% of that from single-model predictions. The promising results from this conceptual model study preliminarily validate the potential of the multi-model coupling approach, offering valuable insights into its potential application to more realistic oceanographic models. Full article

(This article belongs to the Section Ocean and Global Climate)

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25 pages, 33025 KB

Open AccessArticle

Two New Species of Tricoma (Tricoma) (Nematoda: Desmoscolecidae) from Korean Subtidal Sediments, with Notes on Labial Ultrastructure

by Hyo Jin Lee, Heegab Lee, Seungyeop Han and Hyun Soo Rho

J. Mar. Sci. Eng. 2025, 13(12), 2405; https://doi.org/10.3390/jmse13122405 - 18 Dec 2025

Viewed by 157

Abstract

This paper reports two newly discovered species of Tricoma (Tricoma)—T. (T.) discrepans sp. nov. and T. (T.) parasetosa sp. nov.—obtained from the subtidal sediments at a depth of 13 m around Jindo Island, Korea. Tricoma [...] Read more.

This paper reports two newly discovered species of Tricoma (Tricoma)—T. (T.) discrepans sp. nov. and T. (T.) parasetosa sp. nov.—obtained from the subtidal sediments at a depth of 13 m around Jindo Island, Korea. Tricoma (T.) discrepans sp. nov. differs from its congeners in possessing 40–41 main rings, an uncovered first main ring, large vesicular amphidial fovea, and a distinctly thickened tail cuticle that is densely covered with secretions and adhering particles. Somatic setae in males exhibit pronounced sexual dimorphism, with the subventral setae more than twice as thick as the subdorsal setae, a morphological feature documented here for the first time within the subgenus Tricoma (Tricoma). Tricoma (T.) parasetosa sp. nov. can be recognized by 31 (rarely 32) main rings, two pairs of long, thick posterior somatic setae inserted on massive peduncles, a vesicular amphidial fovea extending to the second main ring, and a gubernaculum proximal end gently curved ventrally. Although the labial region is indistinct, the species bears two conspicuous lateral labial projections and a prominent cephalic concretion. Together, these results broaden the current understanding of Tricoma diversity in the northwestern Pacific and emphasize additional morphological variation within Desmoscolecida based on detailed Differential Interference Contrast (DIC) and Scanning Electron Microscope (SEM) analyses. Full article

(This article belongs to the Special Issue Species Diversity and Taxonomy of Marine Nematodes)

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33 pages, 8948 KB

Open AccessArticle

Numerical Simulations of Propulsion Performance of Hull–Propeller–Rudder–Coupled System with Propeller Boss Cap Fins (PBCFs)

by Xiaoqing Tian, Haoliang Zhao, Jinliang Ma, Ming Lv, Hooi-Siang Kang, Junting Wang, Huachen Pan, Du Lin, Songkai Ren and Chizhong Wang

J. Mar. Sci. Eng. 2025, 13(12), 2404; https://doi.org/10.3390/jmse13122404 - 18 Dec 2025

Viewed by 222

Abstract

Ship propulsion performance is important for navigating. This study aims to enhance the propulsion performance of a 9500 DWT ship by integrating PBCFs into the hull–rudder–propeller–coupled system. A total of 27 PBCF models with different fin installation angles, radius ratio, and tilt angles [...] Read more.

Ship propulsion performance is important for navigating. This study aims to enhance the propulsion performance of a 9500 DWT ship by integrating PBCFs into the hull–rudder–propeller–coupled system. A total of 27 PBCF models with different fin installation angles, radius ratio, and tilt angles are designed in the study. The computational fluid dynamics method is employed and a propeller open-water test is also performed to optimize the PBCF design, which is integrated into different coupled systems. The numerical results show that the PBCFs exhibit differential enhancements of propeller performance across system configurations with their efficiency changing from 4.05% to 2.87%. Moreover, the reliability of ship self-propulsion simulation is mutually validated through the combined BF (body force) and MRF (multi-reference frame) methods. Then, simulations were conducted using these two methods for the self-propulsion of a 9500 DWT ship at three different speeds. Finally, the results from using the MRF method show that the incorporation of PBCFs can reduce delivered power to propeller by 1.32% at different F_r. Full article

(This article belongs to the Special Issue Design and Optimization of Ship Hydrodynamics)

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14 pages, 2577 KB

Open AccessArticle

Experimental Study of Ship Oblique Motion in Floating Ice of Different Concentrations

by Qiaosheng Zhao, Jiyu Ma, Zhifu Li and Wei Guo

J. Mar. Sci. Eng. 2025, 13(12), 2403; https://doi.org/10.3390/jmse13122403 - 18 Dec 2025

Viewed by 222

Abstract

This study presents a model experiment on the oblique maneuvering of a ship in a floating ice environment. A series of captive model tests was conducted in both open-water and synthetic ice fields at concentrations of 60%, 70%, and 80%. The model was [...] Read more.

This study presents a model experiment on the oblique maneuvering of a ship in a floating ice environment. A series of captive model tests was conducted in both open-water and synthetic ice fields at concentrations of 60%, 70%, and 80%. The model was tested in a conventional towing tank using non-refrigerated polypropylene ice floes to simulate a broken ice field. Surge force, sway force, and yaw moment on the hull were measured under various drift angles and three speeds. Results show that in oblique motion, ice floes around the hull experience significant overturning and piling up, especially on the drift side, leading to random collisions with the hull. These interactions markedly affect the hydrodynamic forces. As the drift angle increases, the surge, sway, and yaw forces on the hull increase nonlinearly. The comparison between open-water and ice conditions indicates that floating ice can significantly increase the resistance and maneuvering forces. Higher ice concentrations lead to more frequent and more extensive contact between the hull and the ice floes, thereby further amplifying all components of the hydrodynamic forces. This work provides experimental data for validating calculation methods of ship resistance and maneuvering in broken ice. It demonstrates a feasible experimental approach for studying ship maneuvers in a floating ice channel. Full article

(This article belongs to the Special Issue Navigation Performance and Experimental Research of Ships in Ice-Covered Areas (2nd Edition))

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22 pages, 3294 KB

Open AccessArticle

High-Fidelity Decoding Method for Acoustic Data Transmission and Reception of DIFAR Sonobuoy Using Autoencoder

by Yeonjin Park and Jungpyo Hong

J. Mar. Sci. Eng. 2025, 13(12), 2402; https://doi.org/10.3390/jmse13122402 - 18 Dec 2025

Viewed by 169

Abstract

Directional frequency analysis and recording (DIFAR) is a widely used sonobuoy in modern underwater acoustic monitoring and surveillance. The sonobuoy is installed in the area of interest, collects underwater data, and transmits the data to nearby aircraft for data analysis. In this process, [...] Read more.

Directional frequency analysis and recording (DIFAR) is a widely used sonobuoy in modern underwater acoustic monitoring and surveillance. The sonobuoy is installed in the area of interest, collects underwater data, and transmits the data to nearby aircraft for data analysis. In this process, transmission of a large volume of raw data poses significant challenges due to limited communication bandwidth. To address this problem, existing studies on autoencoder-based methods have drastically reduced amounts of information to be transmitted with moderate data reconstruction errors. However, the information bottleneck inherent in these autoencoder-based methods often leads to significant fidelity degradation. To overcome these limitations, this paper proposes a novel autoencoder method focused on the reconstruction fidelity. The proposed method operates with two key components: Gated Fusion (GF), proven critical for effectively fusing multi-scale features, and Squeeze and Excitation (SE), an adaptive Channel Attention for feature refinement. Quantitative evaluations on a realistic simulated sonobuoy dataset demonstrate that the proposed model achieves up to a 90.36% reduction in spectral mean squared error for linear frequency modulation signals compared to the baseline. Full article

(This article belongs to the Section Ocean Engineering)

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33 pages, 9875 KB

Open AccessArticle

An Adaptive Optimization Method for Moored Buoy Site Selection Integrating Ontology Reasoning and Numerical Computation

by Miaomiao Song, Haihui Song, Shixuan Liu, Xiao Fu, Bin Miao, Wenqing Li, Keke Zhang, Wei Hu and Xingkun Yan

J. Mar. Sci. Eng. 2025, 13(12), 2401; https://doi.org/10.3390/jmse13122401 - 18 Dec 2025

Viewed by 183

Abstract

With the growing diversity and complexity of marine monitoring requirements, the scientific deployment of moored buoys has attracted increasing attention. To address the limitations of traditional methods—such as inconsistent knowledge representation, insufficient logical reasoning capacity, and poor adaptability to dynamic marine environments—this study [...] Read more.

With the growing diversity and complexity of marine monitoring requirements, the scientific deployment of moored buoys has attracted increasing attention. To address the limitations of traditional methods—such as inconsistent knowledge representation, insufficient logical reasoning capacity, and poor adaptability to dynamic marine environments—this study proposes an adaptive optimization method for moored buoy site selection integrating ontology reasoning and numerical computation. The proposed approach constructs an ontology model covering key concepts such as buoy specifications, monitoring objectives, and deployment requirements, and further defines formalized reasoning rules to enable automated judgment of deployment feasibility, sensor configuration, and spatial conflict resolution for moored buoy siting. Based on this semantic framework, a spatio-temporal comprehensive variation index (STCVI) is established by integrating temperature, salinity, and current velocity to characterize dynamic oceanographic conditions. Furthermore, a coverage-first greedy algorithm is designed to determine buoy deployment locations, enabling dynamic optimization and environmental adaptability of the buoy station layout. To verify the feasibility and adaptability of the proposed method, simulation experiments are conducted in the Beibu Gulf. Two layout scenarios—an appending layout with existing buoys and an independent layout without existing buoys—are designed to test the method’s adaptability under different deployment conditions. By combining Voronoi spatial partitioning and nearest-neighbor distance analysis, the optimized results are quantitatively evaluated in terms of spatial uniformity and observational effectiveness. The results indicate that the proposed method effectively enhances the spatial rationality and monitoring efficiency of buoy deployment, demonstrating strong generality and scalability. Full article

(This article belongs to the Section Ocean Engineering)

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29 pages, 7748 KB

Open AccessArticle

Mechanism and Regularity of Wet Modes in a Highly Integrated Marine Magnetic Levitation Pump Rotor Under Confined Water Conditions

by Shiyu Fang, Yingsan Wei, Gong Cheng, Qi Liu and Xingyu Wu

J. Mar. Sci. Eng. 2025, 13(12), 2400; https://doi.org/10.3390/jmse13122400 - 18 Dec 2025

Viewed by 253

Abstract

Designed to mitigate the significant low-frequency vibration and noise inherent in conventional marine centrifugal pump systems, the magnetic levitation pump constitutes a novel form of centrifugal pump employing active magnetic bearing technology. While this fully levitated design effectively enhances vibration and noise performance, [...] Read more.

Designed to mitigate the significant low-frequency vibration and noise inherent in conventional marine centrifugal pump systems, the magnetic levitation pump constitutes a novel form of centrifugal pump employing active magnetic bearing technology. While this fully levitated design effectively enhances vibration and noise performance, it results in the complete immersion of the rotor within a confined fluid domain, which contains narrow fluid clearances. This poses significant challenges for the accurate computation of rotor wet modes, which is crucial for the structural design of the rotor system to avoid the resonance induced by flow. Despite exerting a substantially greater influence on rotor wet modal characteristics than unconfined domains, the analysis of rotors under confined fluid conditions has received comparatively little research attention. This study focuses on two types of magnetic levitation pump rotors. From the perspective of analytical modeling, an improved analytical method for wet modal computation based on added mass correction is proposed. The validation of this method included examining two distinct computational approaches for the added mass, the thickening treatment for axially elongated disk components, and the methodology for implementing disk equivalent density. Based on this foundation, wet modal analysis was performed on both rotors utilizing the proposed analytical method, alongside acoustic fluid–structure interaction simulations. The results indicate that for the first bending mode, the errors between the analytical and experimental values are 1.2% and 4.1%, respectively, while the discrepancies between the simulated and experimental values are 0.1% and 3.2%. Finally, regularity analysis was conducted on the wet modal characteristics of the rotor under confined water, considering various fluid clearances. The results reveal that the first three bending modes generally exhibit an increasing trend with the enlargement of the fluid clearance, with a triple-size annulus serving as a transition point. However, increasing the annulus size does not always elevate the modal frequencies above their initial values. This study contributes to understanding the influence mechanisms of confined water on the wet modal properties of magnetic levitation pump rotors. Furthermore, the proposed analytical method improved computational efficiency for the early design stages of water-immersed rotors, alongside a model of greater accuracy essential for magnetic bearing control. Full article

(This article belongs to the Section Ocean Engineering)

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42 pages, 8323 KB

Open AccessArticle

Novel Method for Predicting Linear Velocity Derivative in Modern Ship Hulls and Its Validation Using a Low-Speed Maneuvering Simulator

by Maria Eduarda Felippe Chame, Pedro Cardozo de Mello and Eduardo Aoun Tannuri

J. Mar. Sci. Eng. 2025, 13(12), 2399; https://doi.org/10.3390/jmse13122399 - 18 Dec 2025

Viewed by 430

Abstract

Ship maneuvering prediction relies on hydrodynamic derivatives, traditionally obtained through empirical formulations based on hulls built decades ago. A comparison with experimental data revealed a notable discrepancy, particularly for the linear sway velocity derivative (

Y_{V}^{'}

), where these regression models [...] Read more.

Ship maneuvering prediction relies on hydrodynamic derivatives, traditionally obtained through empirical formulations based on hulls built decades ago. A comparison with experimental data revealed a notable discrepancy, particularly for the linear sway velocity derivative (

Y_{V}^{'}

), where these regression models inadequately capture the behavior of modern hulls. To overcome this limitation, a novel approach is proposed, in which 690 virtual static drift tests were conducted across a systematic series of 115 modern hull forms, parametrically generated in the Grasshopper platform and thus benchmarked against seven vessels. This extensive numerical dataset enabled the development of an updated regression formulation for

Y_{V}^{'}

, which was grounded in key geometric parameters and incorporated specific terms related to the bow and stern shapes. The results obtained by the CFD-based method were compared with those obtained experimentally, confirming the high fidelity of this approach, yielding a maximum relative error of only

4.7 %

for the sway linear velocity derivative. Crucially, when this proposed empirical formula was integrated into a mathematical model (MM-TPN) to predict a ship’s trajectory, it demonstrated substantial improvement by reducing the absolute relative error in standard maneuvers from

23 %

to

10 %

compared with traditional methods used to describe the

Y_{V}^{'}

. Furthermore, an extensive discussion regarding the regression model was conducted, leading to the establishment of the drift angle threshold that invalidates the linear theory (set at

10^{\circ}

for blunt hulls and

8^{\circ}

for slender hulls). A comprehensive three-step validation process, encompassing the

V & V

of the virtual static drift tests, validation of the derived maneuvering coefficient, and validation through standard maneuvers employing the novel approach proposed here, was fully executed. Full article

(This article belongs to the Special Issue Models and Simulations of Ship Manoeuvring)

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Graphical abstract

18 pages, 1002 KB

Open AccessArticle

Study on the Potential Impact of Biofuels on the Operation and Maintenance Durability of Marine Main Engine Components

by Catalin Faitar, Ionut Voicu, Mariana Panaitescu, Andra Nedelcu and Eugen Rusu

J. Mar. Sci. Eng. 2025, 13(12), 2398; https://doi.org/10.3390/jmse13122398 - 17 Dec 2025

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Abstract

The maritime transportation industry is under pressure to reduce the level of emissions generated annually by commercial vessels. In order to achieve this objective, regulatory bodies, both national and international, have imposed strict limitations on the industry, and thus major changes have to [...] Read more.

The maritime transportation industry is under pressure to reduce the level of emissions generated annually by commercial vessels. In order to achieve this objective, regulatory bodies, both national and international, have imposed strict limitations on the industry, and thus major changes have to be made in a tight time frame. In the last decade, engineers and ship designers have been searching for alternatives to traditional fuels, but it is not easy to find a perfect balance between operational costs and economic efficiency. Many potential solutions are being studied, with some of them already proven and implemented, such as liquefied natural gas, solar and wind power, electric propulsion, and many more. One solution might be biofuels, and this study aims to assess the potential impact of their use on the energy performance and durability of a typical marine propulsion engine, namely the MAN B&W 6S70MC-C7, fitted on board many types of ships including large oil tankers, container ships and bulk carriers. The main topic is approached through a progressive structure, starting from the analysis of general characteristics of these fuels and the engine installation, comparative simulations, operational experience, and technical recommendations. The comparative assessment is focused on two traditional types of fuels and two biofuel types. The aim is to identify a viable solution that can sustain the operational efficiency of this main engine without a major impact on its maintenance cycle and without additional costs on the components. Even if these biofuels are more expensive than the traditional ones, in the long run, they could prove to be a better choice in terms of operational costs and compliance with regulation. Full article

(This article belongs to the Section Ocean Engineering)

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26 pages, 4154 KB

Open AccessArticle

Establishment and Evaluation of an Ensemble Bias Correction Framework for the Short-Term Numerical Forecasting on Lower Atmospheric Ducts

by Huan Guo, Bo Wang, Jing Zou, Xiaofeng Zhao, Bin Wang, Zhijin Qiu, Hang Wang, Lu Liu, Xiaolei Liu and Hanyue Wang

J. Mar. Sci. Eng. 2025, 13(12), 2397; https://doi.org/10.3390/jmse13122397 - 17 Dec 2025

Viewed by 194

Abstract

Based on the COAWST (Coupled Ocean–Atmosphere–Wave–Sediment Transport) model, this study developed an atmospheric refractivity forecasting model incorporating ensemble bias correction by combining five bias correction algorithms with the Bayesian Model Averaging (BMA) method. Hindcast tests conducted over the Yellow Sea and Bohai Sea [...] Read more.

Based on the COAWST (Coupled Ocean–Atmosphere–Wave–Sediment Transport) model, this study developed an atmospheric refractivity forecasting model incorporating ensemble bias correction by combining five bias correction algorithms with the Bayesian Model Averaging (BMA) method. Hindcast tests conducted over the Yellow Sea and Bohai Sea regions demonstrated that the ensemble bias correction enhanced both forecasting accuracy and adaptability. On the one hand, the corrected forecasting outperformed the original COAWST model in terms of mean error (ME), root mean square error (RMSE), and correlation coefficient (CC), with the RMSE reduced by approximately 20% below 3000 m altitude. On the other hand, the corrected forecasting reduced the uncertainty associated with the performance of different algorithms. In particular, during typhoon events, the corrected forecasting maintained stable bias characteristics across different height layers through dynamic weight adjustment. Throughout the hindcast period, the ME of the corrected forecasting was lower than that of any single bias correction algorithm. Moreover, compared with other ensemble methods, the corrected forecasting developed in this study achieved more flexible weight allocation through Bayesian optimization, resulting in lower ME. In addition, the corrected forecasting maintained an improvement of approximately 28% in bias reduction even at a 72 h forecasting lead time, demonstrating their robustness and reliability under complex weather conditions. Full article

(This article belongs to the Special Issue Artificial Intelligence and Its Application in Ocean Engineering)

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17 pages, 8979 KB

Open AccessArticle

Application of Hexagonal Reference Maps in Gravity-Assisted Inertial Navigation

by Hongfa Wan, Shanshan Li, Xinxing Li, Yan Huang and Jianbin Zhou

J. Mar. Sci. Eng. 2025, 13(12), 2396; https://doi.org/10.3390/jmse13122396 - 17 Dec 2025

Viewed by 175

Abstract

High-resolution and high-precision marine gravity reference maps are core prerequisites for the practical application of gravity-assisted inertial navigation algorithms, and their accuracy directly determines the performance of the navigation system. In view of the problems existing in the current geographic rectangular grid gravity [...] Read more.

High-resolution and high-precision marine gravity reference maps are core prerequisites for the practical application of gravity-assisted inertial navigation algorithms, and their accuracy directly determines the performance of the navigation system. In view of the problems existing in the current geographic rectangular grid gravity reference map, such as severe polar deformation, poor adjacent consistency, and low positioning accuracy in high latitudes, this study introduces a hexagonal grid system to construct a gravity reference map. It systematically analyzes its compatibility and accuracy in navigation applications. A multi-resolution hexagonal grid scheme with a 7-aperture structure is further proposed to meet the characterization requirements of gravitational fields with different complexities. Experimental verification shows that the accuracy of the gravity-assisted inertial navigation algorithm improved by 0.4%, while that of gravity sequence matching improved by 50%. The proposed hybrid resolution grid can achieve a maximum gravity data compression rate of 68% while ensuring navigation accuracy, especially with regard to the computational efficiency and accuracy requirements of gravity-assisted inertial navigation. Full article

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

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26 pages, 6776 KB

Open AccessArticle

An Improved Adaptive Robust Extended Kalman Filter for Arctic Shipborne Tightly Coupled GNSS/INS Navigation

by Wei Liu, Tengfei Qi, Yuan Hu, Shanshan Fu, Bing Han, Tsung-Hsuan Hsieh and Shengzheng Wang

J. Mar. Sci. Eng. 2025, 13(12), 2395; https://doi.org/10.3390/jmse13122395 - 17 Dec 2025

Viewed by 326

Abstract

In the Arctic region, the navigation and positioning accuracy of shipborne and autonomous underwater vehicle (AUV) integrated Global Navigation Satellite System (GNSS) and Inertial Navigation System (INS) solutions is severely degraded due to poor satellite geometry, frequent ionospheric disturbances, non-Gaussian measurement noise, and [...] Read more.

In the Arctic region, the navigation and positioning accuracy of shipborne and autonomous underwater vehicle (AUV) integrated Global Navigation Satellite System (GNSS) and Inertial Navigation System (INS) solutions is severely degraded due to poor satellite geometry, frequent ionospheric disturbances, non-Gaussian measurement noise, and strong multipath effects, as well as long-term INS-based dead-reckoning for AUVs when GNSS is unavailable underwater. In addition, the sparse ground-based augmentation infrastructure and the lack of reliable reference trajectories and dedicated test ranges in polar waters hinder the validation and performance assessment of existing marine navigation systems, further complicating the achievement of accurate and reliable navigation in this region. To improve the positioning accuracy of the GNSS/INS shipborne navigation system, this paper adopts a tightly coupled GNSS/INS navigation approach. To further enhance the accuracy and robustness of tightly coupled GNSS/INS positioning, this paper proposes an improved Adaptive Robust Extended Kalman Filter (IAREKF) algorithm to effectively suppress the effects of gross errors and non-Gaussian noise, thereby significantly enhancing the system’s robustness and positioning accuracy. First, the residuals and Mahalanobis distance are calculated using the Adaptive Robust Extended Kalman Filter (AREKF), and the chi-square test is used to assess the anomalies of the observations. Subsequently, the observation noise covariance matrix is dynamically adjusted to improve the filter’s anti-interference capability in the complex Arctic environment. However, the state estimation accuracy of AREKF is still affected by GNSS signal degradation, leading to a decrease in navigation and positioning accuracy. To further improve the robustness and positioning accuracy of the filter, this paper introduces a sliding window mechanism, which dynamically adjusts the observation noise covariance matrix using historical residual information, thereby effectively improving the system’s stability in harsh environments. Field experiments conducted on an Arctic survey vessel demonstrate that the proposed improved adaptive robust extended Kalman filter significantly enhances the robustness and accuracy of Arctic integrated navigation. In the Arctic voyages at latitudes 80.3° and 85.7°, compared to the Loosely coupled EKF, the proposed method reduced the horizontal root mean square error by 61.78% and 21.7%, respectively. Full article

(This article belongs to the Section Ocean Engineering)

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37 pages, 12691 KB

Open AccessArticle

Behavior of Shared Suction Anchors in Clay Overlying Silty Sand Soils Considering the Souring Effect

by Jinyi Wang, Kai Liang, Mi Zhou and Ningxin Yang

J. Mar. Sci. Eng. 2025, 13(12), 2394; https://doi.org/10.3390/jmse13122394 - 17 Dec 2025

Viewed by 159

Abstract

This paper investigates, through finite element analysis, the bearing capacity behavior of the shared suction anchors in clay-covered silt soil layers, considering the effects of soil scour. Its aim is to address the anchors’ failure mechanisms and corresponding bearing capacity. The numerical model [...] Read more.

This paper investigates, through finite element analysis, the bearing capacity behavior of the shared suction anchors in clay-covered silt soil layers, considering the effects of soil scour. Its aim is to address the anchors’ failure mechanisms and corresponding bearing capacity. The numerical model was validated against previously reported data, with good agreement obtained. The main findings are as follows: (1) the tensional force T exerts an influence on the horizontal bearing capacity; (2) it is proven that scour significantly affects the failure mechanism of the suction anchor in clay overlying silty sand and, consequently, the corresponding bearing capacity; and (3) a bearing capacity design process for the shared suction anchor subjected to combined VHMT loading in clay-covered silt soil layers, considering soil scour, is proposed to provide guidance for practical engineering. Full article

(This article belongs to the Section Ocean Engineering)

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35 pages, 40296 KB

Open AccessArticle

A Matheuristic Framework for Behavioral Segmentation and Mobility Analysis of AIS Trajectories Using Multiple Movement Features

by Fumi Wu, Yangming Liu, Ronghui Li and Stefan Voß

J. Mar. Sci. Eng. 2025, 13(12), 2393; https://doi.org/10.3390/jmse13122393 - 17 Dec 2025

Viewed by 315

Abstract

Accurate behavioral segmentation of vessel trajectories from Automatic Identification System (AIS) is essential for maritime safety and traffic management. Existing methods often rely on predefined thresholds or emphasize geometric criteria and offer limited behavioral interpretability for mobility analysis. This paper introduces an unsupervised [...] Read more.

Accurate behavioral segmentation of vessel trajectories from Automatic Identification System (AIS) is essential for maritime safety and traffic management. Existing methods often rely on predefined thresholds or emphasize geometric criteria and offer limited behavioral interpretability for mobility analysis. This paper introduces an unsupervised behavioral segmentation framework that integrates clustering with matheuristic optimization. Trajectories are cleaned with a forward sliding window, and three smoothed movement features, namely speed, acceleration, and turning rate, are computed for each point. Each feature is discretized by the Jenks Natural Breaks algorithm to extract key feature points and pointwise feature labels. Segment boundaries are near-optimally chosen from these key feature points using a Matheuristic Fixed Set Search (MFSS) that minimizes a Minimum Description Length (MDL) objective. This ensures behavioral consistency within each segment and clear separation between adjacent segments. Experiments on an AIS dataset from the Qiongzhou Strait, China, demonstrate that our proposed method yields more compact, distinctly differentiated segments than baseline methods, while preserving intra-segment behavioral continuity. These segments exhibit strong semantic coherence, making them well-suited for downstream tasks such as traffic risk assessment and route planning. Full article

(This article belongs to the Section Ocean Engineering)

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29 pages, 4874 KB

Open AccessArticle

Hierarchical Control for USV Trajectory Tracking with Proactive–Reactive Reward Shaping

by Zixiao Luo, Dongmei Du, Dandan Liu, Qiangqiang Yang, Yi Chai, Shiyu Hu and Jiayou Wu

J. Mar. Sci. Eng. 2025, 13(12), 2392; https://doi.org/10.3390/jmse13122392 - 17 Dec 2025

Cited by 1 | Viewed by 301

Abstract

To address trajectory tracking of underactuated unmanned surface vessels (USVs) under disturbances and model uncertainty, we propose a hierarchical control framework that combines model predictive control (MPC) with proximal policy optimization (PPO). The outer loop runs in the inertial reference frame, where an [...] Read more.

To address trajectory tracking of underactuated unmanned surface vessels (USVs) under disturbances and model uncertainty, we propose a hierarchical control framework that combines model predictive control (MPC) with proximal policy optimization (PPO). The outer loop runs in the inertial reference frame, where an MPC planner based on a kinematic model enforces velocity and safety constraints and generates feasible body–fixed velocity references. The inner loop runs in the body–fixed reference frame, where a PPO policy learns the nonlinear inverse mapping from velocity to multi–thruster thrust, compensating hydrodynamic modeling errors and external disturbances. On top of this framework, we design a Proactive–Reactive Adaptive Reward (PRAR) that uses the MPC prediction sequence and real–time pose errors to adaptively reweight the reward across surge, sway and yaw, improving robustness and cross–model generalization. Simulation studies on circular and curvilinear trajectories compare the proposed PRAR–driven dual–loop controller (PRAR–DLC) with MPC–PID, PPO–Only, MPC–PPO and PPO variants. On the curvilinear trajectory, PRAR–DLC reduces surge MAE and maximum tracking error from 0.269 m and 0.963 m (MPC–PID) to 0.138 m and 0.337 m, respectively; on the circular trajectory it achieves about an 8.5% reduction in surge MAE while maintaining comparable sway and yaw accuracy to the baseline controllers. Real–time profiling further shows that the average MPC and PPO evaluation times remain below the control sampling period, indicating that the proposed architecture is compatible with real–time onboard implementation and physical deployment. Full article

(This article belongs to the Section Ocean Engineering)

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20 pages, 4811 KB

Open AccessArticle

A Hybrid Statistical and Neural Network Method for Detecting Abnormal Ship Behavior Using Leisure Boat Sea Trial Data in a Marina Port

by Hoang Thien Vu, Van Thuan Mai, Thi Thanh Diep Nguyen, Hyeon Kyu Yoon and Hujae Choi

J. Mar. Sci. Eng. 2025, 13(12), 2391; https://doi.org/10.3390/jmse13122391 - 17 Dec 2025

Viewed by 212

Abstract

Effective abnormal behavior detection in ship operations is essential for ensuring navigational safety and operational efficiency in marina ports. This study presents a hybrid method that integrates statistical analysis and neural network modeling to detect abnormal behavior based on data obtained through leisure [...] Read more.

Effective abnormal behavior detection in ship operations is essential for ensuring navigational safety and operational efficiency in marina ports. This study presents a hybrid method that integrates statistical analysis and neural network modeling to detect abnormal behavior based on data obtained through leisure boat sea trials. Detection criteria were established based on ship motion characteristics, operating area conditions, and the properties of the sea trial data. The method combines Rayda’s criterion and standard deviation thresholds to identify sudden changes in measured data, while a Long Short-Term Memory (LSTM) network is used to predict normal ship behavior. Deviations between predicted and measured values were evaluated using three thresholds (levels 1, 2, and 3), with level 3 effectively isolating the most significant abnormal data (representing 2–10% of the data). The proposed method is capable of successfully identifying sudden acceleration or deceleration, unusual course changes, extended stationary periods, deviations from expected routes, complex maneuvers, and track continuity issues. The results demonstrate that the proposed hybrid method can reliably distinguish abnormal ship behaviors based on real sea trial data. To separate true abnormalities from false alarms or sensor and environmental noise, its practical application on a real ship is planned as future work. This study provides a foundation for intelligent ship monitoring systems and supports the development of autonomous and semi-autonomous navigation technologies. Full article

(This article belongs to the Section Ocean Engineering)

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20 pages, 18012 KB

Open AccessArticle

Effects of Mesoscale Eddies on Acoustic Propagation with Preliminary Analysis of Topographic Influences

by Xueqin Zhang, Cheng Lou, Yusheng Jia, Kunde Yang and Xiaolin Yu

J. Mar. Sci. Eng. 2025, 13(12), 2390; https://doi.org/10.3390/jmse13122390 - 17 Dec 2025

Viewed by 183

Abstract

This study investigates underwater acoustic propagation patterns under mesoscale eddy conditions through numerical modeling and parametric analysis. A mathematical model of mesoscale eddies was developed, and acoustic transmission loss was computed using the BELLHOP ray-tracing model. Systematic simulations were conducted to examine the [...] Read more.

This study investigates underwater acoustic propagation patterns under mesoscale eddy conditions through numerical modeling and parametric analysis. A mathematical model of mesoscale eddies was developed, and acoustic transmission loss was computed using the BELLHOP ray-tracing model. Systematic simulations were conducted to examine the effects of source depth, eddy polarity (cold/warm), eddy intensity, and seabed topography. The results reveal distinct acoustic behaviors: cold-core eddies shift convergence zones forward, reduce their width, elevate their depth, and enhance convergence gain within certain ranges. In contrast, warm-core eddies displace convergence zones backward, broaden their width, and can induce surface duct formation. Furthermore, seabed topography exerts minimal influence on acoustic propagation under cold-core eddies but significantly modulates propagation under warm-core eddies, with different topographies producing markedly distinct effects. These findings provide valuable insights for marine scientific research and engineering applications leveraging mesoscale eddy phenomena. Full article

(This article belongs to the Section Physical Oceanography)

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17 pages, 4347 KB

Open AccessArticle

Emissions Performance Assessment of a Retrofitted Marine Genset Combusting Biomethane in Dual-Fuel Mode

by George Mallouppas, Ashok Kumar, Pavlos Loizou and Sotiris Petrakides

J. Mar. Sci. Eng. 2025, 13(12), 2389; https://doi.org/10.3390/jmse13122389 - 17 Dec 2025

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Abstract

The purpose of this research article is to assess the emissions performance of a marine genset that was retrofitted to combust biomethane in a dual-fuel mode. The retrofits are part of our research efforts to provide a green cold-ironing solution for vessels at [...] Read more.

The purpose of this research article is to assess the emissions performance of a marine genset that was retrofitted to combust biomethane in a dual-fuel mode. The retrofits are part of our research efforts to provide a green cold-ironing solution for vessels at berth or in anchorage, and to advocate for a greener electrification of the port sector. An experimental campaign is presented to test the emissions performance by substituting biomethane as an energy basis. Up to 60% biomethane energy substitution is tested under low, medium, and high engine loads. The engine load is controlled via a resistive load bank, and the respective emissions were captured using portable gas analyzers. The results reveal a poor utilization of the gaseous fuel, leading to low engine efficiencies, high CO, and unburnt hydrocarbons at low and intermediate engine loads. However, marine gensets are utilized at high engine loads. At these loads, the specific fuel consumption improves. As indicated in the open literature, biomethane leads to high CO, and unburnt hydrocarbons and the respective NO_x emissions drop compared to diesel-only cases. Full article

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24 pages, 3603 KB

Open AccessArticle

Research on Multi-UUVs Dynamic Formation Reconfiguration Considering Underwater Acoustic Communication Characteristics

by Chuang Wan, Tao Chen, Zhenghong Liu and Yunyao Fan

J. Mar. Sci. Eng. 2025, 13(12), 2388; https://doi.org/10.3390/jmse13122388 - 16 Dec 2025

Viewed by 198

Abstract

This study investigates the dynamic formation reconfiguration problem for multi-UUV (multi-Unmanned Underwater Vehicle) systems, with a particular focus on the challenges posed by underwater acoustic communication. A two-dimensional grid model is established in the horizontal plane, taking the leader vehicle as a reference [...] Read more.

This study investigates the dynamic formation reconfiguration problem for multi-UUV (multi-Unmanned Underwater Vehicle) systems, with a particular focus on the challenges posed by underwater acoustic communication. A two-dimensional grid model is established in the horizontal plane, taking the leader vehicle as a reference point. Based on this model, fundamental motion strategies for formation reconfiguration are proposed. To facilitate reconfiguration, the Particle Swarm Optimization (PSO) algorithm is utilized to assign desired position points to the follower UUVs within the new formation, enabling dynamic target point planning during reconfiguration. Furthermore, the process of generating motion guidance commands and the impact of acoustic communication delays during command transmission are analyzed. To address these delays, a fuzzy logic-based delay compensation method is proposed. Simulation experiments were conducted to validate the proposed approach. The results demonstrate that the formation reconfiguration planning method and the centralized command communication compensation strategy are both effective and practical for multi-UUV systems. Full article

(This article belongs to the Section Ocean Engineering)

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17 pages, 6015 KB

Open AccessArticle

Development and Application of a Polar Ice-Based Ecological Observation Buoy

by Xing Han, Guoxuan Liu, Liwei Kou and Yinke Dou

J. Mar. Sci. Eng. 2025, 13(12), 2387; https://doi.org/10.3390/jmse13122387 - 16 Dec 2025

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Abstract

Addressing the current situation where in situ observations in the Arctic primarily target physical and a few biogeochemical parameters, leaving a gap in systematic direct observation of biological populations beneath sea ice, this study developed a polar ice-based ecological observation buoy system. Building [...] Read more.

Addressing the current situation where in situ observations in the Arctic primarily target physical and a few biogeochemical parameters, leaving a gap in systematic direct observation of biological populations beneath sea ice, this study developed a polar ice-based ecological observation buoy system. Building upon conventional meteorological and oceanographic hydrographic sensors, this system innovatively integrates an underwater imaging module and key technologies such as machine learning-based automatic fish target recognition and reliable dual-channel satellite data transmission in polar environments. Its successful deployment during the 2025 15th Chinese National Arctic Research Expedition verified the system’s stability. During the initial one-month operation period (designed for a monitoring cycle of not less than one year), the data return rates for conventional and image data reached 100% and 96.8%, respectively, achieving quasi-real-time continuous observation of physical and ecological parameters at the air–sea interface in the Arctic Ocean, and it is capable of acquiring not only physical parameters but also visual observations of under-ice fauna. The system successfully acquired and transmitted images containing suspected biological targets and reference objects, providing the first in situ, image-based biological observation dataset for the central Arctic Ocean. This work establishes a new methodological capability for direct ecological monitoring, offering essential equipment support for quantifying biological presence, studying population dynamics, and informing evidence-based polar ecosystem governance. Full article

(This article belongs to the Section Marine Ecology)

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20 pages, 3497 KB

Open AccessArticle

Effect of Following Current on the Hydroelastic Behavior of a Floating Ice Sheet near an Impermeable Wall

by Sarat Chandra Mohapatra, Pouria Amouzadrad and C. Guedes Soares

J. Mar. Sci. Eng. 2025, 13(12), 2386; https://doi.org/10.3390/jmse13122386 - 16 Dec 2025

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Abstract

A theoretical model of the interaction between a following current and a semi-infinite floating ice sheet under compressive stress near a vertical impermeable wall is developed, within the scope of linear water wave theory, to study the hydroelastic behavior. The conceptual framework defining [...] Read more.

A theoretical model of the interaction between a following current and a semi-infinite floating ice sheet under compressive stress near a vertical impermeable wall is developed, within the scope of linear water wave theory, to study the hydroelastic behavior. The conceptual framework defining the buoyant ice structure incorporates the tenets of elastic beam theory. The associated fluid dynamics are governed by strict adherence to the potential flow paradigm. To resolve the undetermined parameters appearing in the Fourier series decomposition of the potential functions, investigators systematically apply higher-order criteria detailing the coupling relationships between modes. The current results are compared with a specific case of results available in the literature, and the convergence analysis of the analytical solution is made for computational accuracy. Further, the free edge conditions are applied at the edge of the floating ice sheet, and the effects of current speed, compressive stress, the thickness of the ice sheet, flexural rigidity, water depth on the strain, displacements, reflection wave amplitude, and the horizontal force on the rigid vertical wall are analyzed in detail. It is found that the higher values of the following current heighten the strain, displacements, reflection amplitude, and force on the wall. The study’s outcomes are considered to benefit not just cold region design applications but also the engineering of resilient floating structures for oceanic and offshore environments, and to the design of marine structures. Full article

(This article belongs to the Section Ocean Engineering)

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24 pages, 5536 KB

Open AccessArticle

Research on Subsea Cluster Layout Optimization Method Considering Three-Dimensional Terrain Constraints

by Weizheng An, Wenze Liu, Xiaohui Song, Yingying Wang, Qiang Ma, Yangqing Lin and Yiyang Xue

J. Mar. Sci. Eng. 2025, 13(12), 2385; https://doi.org/10.3390/jmse13122385 - 16 Dec 2025

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Abstract

Seabed topography is a key factor affecting the layout of underwater production systems. Developing a more scientific, intelligent, and integrated layout optimization method is the key to optimizing the layout of underwater production systems. To address the challenge of acquiring a more scientific, [...] Read more.

Seabed topography is a key factor affecting the layout of underwater production systems. Developing a more scientific, intelligent, and integrated layout optimization method is the key to optimizing the layout of underwater production systems. To address the challenge of acquiring a more scientific, intelligent, and integrated optimization method, this paper proposes a multi-level integrated optimization model that incorporates three-dimensional seabed topography, obstacle areas, target locations, pipeline paths, and manifold connection relationships, with the primary objective of minimizing total investment cost. A hybrid algorithm combining H-MOPSO (Hierarchical Multi-Objective Particle Swarm Optimization) with K-means-ILP clustering, dynamic programming, and TEWA* pathfinding is raised to collaboratively solve for the global optimal layout, achieving a coupled “target grouping-manifold connection-path optimization” design. Based on the actual oilfield seabed topography and target data, this paper carries out case analysis and algorithm comparison experiments. The results show that the optimization method in this paper can significantly improve the layout economy and cost accuracy under the premise of meeting the engineering constraints. Among them, the PLEM parallel connection method reduces the pipeline laying cost by 25.72% and the overall layout investment cost by 5.39% compared with the traditional manifold series scheme. Full article

(This article belongs to the Section Geological Oceanography)

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31 pages, 2685 KB

Open AccessReview

Predicting Coastal Flooding and Overtopping with Machine Learning: Review and Future Prospects

by Moeketsi L. Duiker, Victor Ramos, Francisco Taveira-Pinto and Paulo Rosa-Santos

J. Mar. Sci. Eng. 2025, 13(12), 2384; https://doi.org/10.3390/jmse13122384 - 16 Dec 2025

Viewed by 353

Abstract

Flooding and overtopping are major concerns in coastal areas due to their potential to cause severe damage to infrastructure, economic activities, and human lives. Traditional methods for predicting these phenomena include numerical and physical models, as well as empirical formulations. However, these methods [...] Read more.

Flooding and overtopping are major concerns in coastal areas due to their potential to cause severe damage to infrastructure, economic activities, and human lives. Traditional methods for predicting these phenomena include numerical and physical models, as well as empirical formulations. However, these methods have limitations, such as the high computational costs, reliance on extensive field data, and reduced accuracy under complex conditions. Recent advances in machine learning (ML) offer new opportunities to improve predictive capabilities in coastal engineering. This paper reviews ML applications for coastal flooding and overtopping prediction, analyzing commonly used models, data sources, and preprocessing techniques. Several studies report that ML models can match or exceed the performance of traditional approaches, such as empirical EurOtop formulas or high-fidelity numerical models, particularly in controlled laboratory datasets where numerical models are computationally intensive and empirical methods show larger estimation errors. However, their advantages remain task- and data-dependent, and their generalization and interpretability may lag behind physics-based methods. This review also examines recent developments, such as hybrid approaches, real-time monitoring, and explainable artificial intelligence, which show promise in addressing these limitations and advancing the operational use of ML in coastal flooding and overtopping prediction. Full article

(This article belongs to the Special Issue Coastal Disaster Assessment and Response—2nd Edition)

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18 pages, 4649 KB

Open AccessArticle

Assessment of Short-Term Sediment Deposition Patterns Along the Palamós Submarine Canyon (NW Mediterranean) Using ²³⁴Th

by Maria Sierks, Sarah Paradis, Montserrat Roca-Martí, Viena Puigcorbé and Pere Puig

J. Mar. Sci. Eng. 2025, 13(12), 2383; https://doi.org/10.3390/jmse13122383 - 16 Dec 2025

Viewed by 2188

Abstract

Sedimentary dynamics in the Palamós Canyon are influenced by river inputs and storm resuspension, as well as by bottom trawling on the canyon flanks. In this study, we estimate recent sediment deposition patterns along the canyon axis using the excess activity concentration of [...] Read more.

Sedimentary dynamics in the Palamós Canyon are influenced by river inputs and storm resuspension, as well as by bottom trawling on the canyon flanks. In this study, we estimate recent sediment deposition patterns along the canyon axis using the excess activity concentration of the short-lived radiotracer ²³⁴Th (half-life of 24.1 days). Sediment cores were obtained at various locations along the canyon axis from a depth of approximately 800 m to 2100 m in June 2023 and August 2024. Excess ²³⁴Th (²³⁴Th_xs) was detected in all sampled sites with variable penetration depths (0.5–3.5 cm). ²³⁴Th_xs-derived estimations of mixing rates decreased downcanyon from up to 15.6 cm² y⁻¹ at the canyon head (~800 m) to negligible mixing at the canyon mouth (~2100 m). ²³⁴Th_xs inventories, a proxy of recent sediment deposition, were high (1800–3490 Bq m⁻²) at the canyon head and at the upper canyon (~1400 m) close to fishing grounds and decreased downcanyon (82–694 Bq m⁻²) at the lower canyon (~1800 m) and canyon mouth. Inventories varied 2-fold across years presumably attributed to enhanced riverine and bottom trawling sediment fluxes. Similar ²³⁴Th-derived sediment deposition patterns can be found in submarine canyons worldwide, highlighting the value of this radiotracer for sedimentary dynamics studies in such complex environments. Full article

(This article belongs to the Section Marine Environmental Science)

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27 pages, 1532 KB

Open AccessArticle

Assessing the Resilience of Specialized Terminals Within Coastal Port Transportation Systems: An Improved RBOP Method

by Qi Tian, Kun Du and Yumei Liang

J. Mar. Sci. Eng. 2025, 13(12), 2382; https://doi.org/10.3390/jmse13122382 - 16 Dec 2025

Viewed by 194

Abstract

Specialized terminals in coastal ports play an increasingly important role in maritime transport. To enhance the resilience of specialized terminals, it is vital to increase their ability to maintain a certain level of function under various emergencies. This effort is fundamental to ensuring [...] Read more.

Specialized terminals in coastal ports play an increasingly important role in maritime transport. To enhance the resilience of specialized terminals, it is vital to increase their ability to maintain a certain level of function under various emergencies. This effort is fundamental to ensuring the handling efficiency of coastal ports and the stability of the shipping network. In this paper, from the perspective of the coastal port transportation system, we developed a resilience evaluation framework considering micro-level, meso-level, and macro-level influencing factors on specialized terminals. To evaluate the comprehensive resilience of the specialized terminal, we quantitatively calculated each evaluation indicator and proposed an improved Ranking Based on Optimal Points (RBOP) method. The application results were obtained from a study on specialized container terminals at eight hub ports in coastal China. The improved RBOP method takes into account both the current status and future development trends of specialized terminals. As a result, compared with TOPSIS, VIKOR, Multi-MOORA, and WASPAS, the ranking results of the improved RBOP and the latest method (i.e., WASPAS) are the closest, which only differ in the seventh and eighth ranking, while the outcomes of the improved RBOP align more closely with expert expectations. The proposed method enables the resilience evaluation of specialized terminals from a holistic perspective of the coastal port transportation system. This helps port managers identify bottlenecks in the resilience of specialized terminals and can enhance the efficiency and stability of port operations. Full article

(This article belongs to the Special Issue Maritime Security and Risk Assessments—2nd Edition)

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38 pages, 5631 KB

Open AccessArticle

A New Methodology for Coastal Erosion Risk Assessment—Case Study: Calabria Region

by Giuseppina Chiara Barillà, Giuseppe Barbaro, Giandomenico Foti and Giuseppe Mauro

J. Mar. Sci. Eng. 2025, 13(12), 2381; https://doi.org/10.3390/jmse13122381 - 16 Dec 2025

Viewed by 329

Abstract

The coastal environment is a dynamic system shaped by both natural processes and human activities. In recent decades, increasing anthropogenic pressure and climate change—manifested through sea-level rise and more frequent extreme events—have accelerated coastal retreat, highlighting the need for improved management strategies and [...] Read more.

The coastal environment is a dynamic system shaped by both natural processes and human activities. In recent decades, increasing anthropogenic pressure and climate change—manifested through sea-level rise and more frequent extreme events—have accelerated coastal retreat, highlighting the need for improved management strategies and standardized tools for coastal risk assessment. Existing approaches remain highly heterogeneous, differing in structure, input data, and the range of factors considered. To address this gap, this study proposes an index-based methodology of general validity designed to quantify coastal erosion risk through the combined analysis of hazard, vulnerability, and exposure factors. The approach was developed for multi-scale and multi-risk applications and implemented across 54 representative sites along the Calabrian coast in southern Italy, demonstrating strong adaptability and robustness for regional-scale assessments. Results reveal marked spatial variability in coastal risk, with the Tyrrhenian sector exhibiting the highest values due to the combined effects of energetic wave conditions and intense anthropogenic pressure. The proposed framework can be easily integrated into open-access GIS platforms to support evidence-based planning and decision-making, offering practical value for public administrations and stakeholders, and providing a flexible, accessible tool for integrated coastal risk management. Full article

(This article belongs to the Special Issue Climate Change Impacts on Hydrodynamic and Morphodynamic Coastal Processes)

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J. Mar. Sci. Eng., Volume 13, Issue 12 (December 2025) – 196 articles

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