Journal of Marine Science and Engineering

21 pages, 2052 KB

Open AccessArticle

Inverse Identification of Temperature- and Mode-Dependent Apparent Complex Flexural Properties of Syntactic Foam for Low-Temperature Marine Insulation

by Byungmo Kim, Kiyoung Sung, Junghee Lee and Cheonhong Min

J. Mar. Sci. Eng. 2026, 14(17), 1590; https://doi.org/10.3390/jmse14171590 - 28 Aug 2026

Abstract

Syntactic foams combine low density and thermal-insulation capability, but their dynamic flexural properties at subzero temperatures remain insufficiently characterized. This study applied an Euler–Bernoulli beam-based inverse framework to natural frequencies and damping ratios of four epoxy syntactic-foam specimens representing four formulations at 0, [...] Read more.

Syntactic foams combine low density and thermal-insulation capability, but their dynamic flexural properties at subzero temperatures remain insufficiently characterized. This study applied an Euler–Bernoulli beam-based inverse framework to natural frequencies and damping ratios of four epoxy syntactic-foam specimens representing four formulations at 0, −20, and −40 °C. Apparent storage, loss, and complex flexural moduli and equivalent modal loss factors were identified for the first two bending modes, with intermodal consistency and analytical sensitivity evaluated. The storage flexural modulus increased with decreasing temperature for every specimen and mode, with first-mode increases of approximately 5.8–11.0% from 0 to −40 °C. At equal nominal weight fractions, the S38HS-based specimens exhibited higher storage flexural moduli than the corresponding S28HS-based specimens. First- and second-mode estimates agreed within 5% for most conditions, while S4 showed a 10.93% discrepancy at −40 °C. Equivalent modal loss factors were non-monotonic and more variable in the second mode; the maximum values,

η_{2}

= 0.1040 and

E_{2}^{''}

= 0.298 GPa, occurred for S3 at −40 °C. Effective free length showed the greatest normalized influence on the inverse estimate. The identified properties provide temperature- and mode-specific, coupon-level effective inputs for preliminary vibration analyses of moderately low-temperature marine insulation components under comparable conditions. Full article

(This article belongs to the Special Issue Structural Modelling, Safety Assessment, and Advanced Material Application of Marine Structures—2nd Edition)

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25 pages, 2269 KB

Open AccessArticle

Current-Time Typhoon-Induced Storm Surge Estimation at Lianyungang: A Fully Nested Event-Grouped Evaluation

by Rui Liu, Dewei Wang, Shuaikang Zhao, Jierui Tang, Xue Li and Wenli Qiao

J. Mar. Sci. Eng. 2026, 14(17), 1589; https://doi.org/10.3390/jmse14171589 - 28 Aug 2026

Abstract

Storm surge current-time estimations are strongly influenced by recent water-level conditions, while the temporal dependence among samples from the same typhoon event can complicate the assessment of model generalization to unseen events. This study evaluated storm surge estimation at the Lianyungang tide gauge [...] Read more.

Storm surge current-time estimations are strongly influenced by recent water-level conditions, while the temporal dependence among samples from the same typhoon event can complicate the assessment of model generalization to unseen events. This study evaluated storm surge estimation at the Lianyungang tide gauge using 2168 samples from 28 typhoon events during 2002–2024. A 41-feature extreme gradient boosting (XGBoost) model integrating historical surge and physics-motivated information was evaluated using fully nested event-grouped cross-validation, with complete outer-test typhoon events excluded from hyperparameter optimization, early stopping, and model fitting. The 41-feature XGBoost model achieved a mean absolute error (MAE) of 0.083 m, a root mean square error (RMSE) of 0.128 m, and a coefficient of determination (R²) of 0.794. On the common valid sample subset, its RMSE was 9.15% lower than that of Persistence, and it achieved a lower event-level RMSE in 18 of the 28 independently held-out typhoon events. Controlled information-source experiments showed that historical surge information accounted for most of the aggregate predictive skill, whereas adding core storm-state variables and the complete set of physics-motivated descriptors produced only limited changes in overall performance. The relative improvement over Persistence was larger for samples in which the shortest available historical surge lag was 3–6 h than for those with a 1 h lag, but this advantage did not extend consistently to the highest-surge conditions, where systematic underestimation remained evident. These results demonstrate the importance of event-independent validation for assessing machine-learning storm surge estimation and show that the model skill depends strongly on both information availability and the surge magnitude. The framework should be interpreted as a retrospective, single-station current-time estimation approach rather than an operational forecasting or extreme-surge warning system. Full article

(This article belongs to the Section Marine Hazards)

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23 pages, 3974 KB

Open AccessArticle

Topographic and Human-Pressure Interactions in Micro-Island Ecological Quality: A Geodetector-Based Framework from Jiangsu, China

by Zijie Li, Shufen Guo, Dejin Zhang, Weichen Shi, Jialong Sun and Baozhang Chen

J. Mar. Sci. Eng. 2026, 14(17), 1588; https://doi.org/10.3390/jmse14171588 - 27 Aug 2026

Abstract

Island ecosystems are highly sensitive to climate change and intensive human activities. However, most existing assessments rely on subjective weighting and linear assumptions, which may not capture nonlinear temporal evolution and can be distorted by spatial-scale effects, including extreme density outliers on micro-islands. [...] Read more.

Island ecosystems are highly sensitive to climate change and intensive human activities. However, most existing assessments rely on subjective weighting and linear assumptions, which may not capture nonlinear temporal evolution and can be distorted by spatial-scale effects, including extreme density outliers on micro-islands. Focusing on five representative islands in Jiangsu Province, China (2014–2024), this study applies a data-driven evaluation framework. First, we constructed an Island Ecological Quality Index (IEQI) using principal component analysis (PCA) to integrate multidimensional ecological-state variables. Second, to reduce sensitivity to selected scale-related extremes in spatially restricted units, we employed a geographical detector model to identify explanatory factors and characterize interactive associations. The IEQI showed a nonlinear temporal trajectory, with fluctuations followed by recovery and stabilization after 2021. Under the robust adaptive Jenks classification, the factor detector showed high relative explanatory power for Artificial Shoreline Ratio (q = 0.8457), Population Density (q = 0.8339), Terrain Index (q = 0.8135), Tourist Density (q = 0.6282), and Built-up Ratio (q = 0.3189). Interaction analysis identified bi-factor enhancement between Terrain Index and Population Density (q = 0.8364) and nonlinear enhancement between Policy Count and Built-up Ratio (q = 0.6424). These q statistics describe spatial explanatory associations rather than causal effects. These findings challenge linear and generalized coastal management paradigms. We propose a “one island, one policy” framework that explicitly distinguishes micro-islands by their topographic buffering capacity and anthropogenic pressure profiles, enabling spatially targeted conservation and restoration strategies. Full article

(This article belongs to the Special Issue Selected Feature Papers in Marine Environmental Science)

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32 pages, 3746 KB

Open AccessArticle

Data-Driven Evolutionary Belief Rule Base Modelling for Explainable Arctic Navigation Safety Assessment

by Zhengqi Wang, Shuaiyu Yao, Chenyi Zhao and Wendi Ouyang

J. Mar. Sci. Eng. 2026, 14(17), 1587; https://doi.org/10.3390/jmse14171587 - 27 Aug 2026

Abstract

The Arctic Northeast Passage is of growing economic and strategic importance, while its harsh and highly variable navigation environment poses substantial challenges for vessel operation. Existing assessment approaches often rely on predefined structural assumptions or sacrifice interpretability for numerical performance. This study proposes [...] Read more.

The Arctic Northeast Passage is of growing economic and strategic importance, while its harsh and highly variable navigation environment poses substantial challenges for vessel operation. Existing assessment approaches often rely on predefined structural assumptions or sacrifice interpretability for numerical performance. This study proposes a data-driven evolutionary belief rule base model that integrates an adaptive reference value field mechanism with differential evolution-based structural optimization for rule pruning and growth. The inputs are observed vessel-operational and environmental variables from the Oden and Tian En datasets, and the output targets are three-grade expert-consensus navigation safety risk distributions aggregated from 100 independent votes per sample. Under the repeated random-split evaluations, ARVF-DEBRB achieved the lowest mean MAE on Oden and errors comparable to the leading learned baselines; on Tian En, its mean errors were comparable to those of the strongest learned baselines while lower than those of several conventional and deep baselines. Complementary chronological rolling-window evaluations over three disjoint future test windows provided future-only evidence as follows: ARVF-DEBRB ranked second in RMSE and third in MAE on Oden, and first in RMSE and second in MAE on Tian En. The rolling factorial ablation obtained the lowest mean errors for the complete configuration on both datasets. These results indicate competitive predictive performance under the reported evaluation protocols, while preserving transparent IF-THEN reasoning semantics and a compact rule structure. The data-adaptive ARVF construction and DE-based rule-structure refinement provide a methodological basis for recalibrating the framework to new operational settings. Full article

(This article belongs to the Section Ocean Engineering)

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33 pages, 1440 KB

Open AccessArticle

A Novel Time-Varying Failure Risk Assessment Framework for Marine Diesel Engines Integrating Large Language Models and Bayesian Networks

by Siheng Zhao, Zixiang Zhu, Shifei Ma, Jing Zhang, Tingting Li and Zhihua Chen

J. Mar. Sci. Eng. 2026, 14(17), 1586; https://doi.org/10.3390/jmse14171586 - 27 Aug 2026

Abstract

Fault risks in marine diesel engines (MDEs) propagate across coupled subsystems and evolve with component degradation, but existing methods rarely integrate accident narratives, causal structure, and time-varying reliability. This study develops a novel framework that integrates large language models (LLMs), rough–fuzzy DEMATEL, interpretive [...] Read more.

Fault risks in marine diesel engines (MDEs) propagate across coupled subsystems and evolve with component degradation, but existing methods rarely integrate accident narratives, causal structure, and time-varying reliability. This study develops a novel framework that integrates large language models (LLMs), rough–fuzzy DEMATEL, interpretive structural modeling (ISM), and Bayesian networks (BNs) with service-time-dependent priors for time-varying failure analysis. First, the risk-influencing factors (RIFs) are extracted from accident and maintenance records using LLMs, text embeddings, semantic clustering, and expert consolidation. Rough–fuzzy DEMATEL and ISM are used to identify causal relationships and the hierarchical structure. The RIFs, bottom-level components, and target failure are then mapped into a multilayer BN parameterized using Noisy-OR relationships and Weibull-derived time-varying priors. In a case study of MDE hard starting, 338 cause descriptions from 35 records yielded 12 RIFs, with semantic coverage above 93% across four evaluation models. When hard starting was observed, the posterior probability of mechanical failure of the fuel injection system reached 60.92%, compared with 36.91% for governor and mechanical actuation system failure. Over 0–10,000 h of cumulative service, the model-inferred probability of hard starting during a single starting attempt increased from 38.09% to 75.23% under the specified model parameterization. The framework supports causal interpretation, troubleshooting prioritization, and service-time-dependent maintenance prioritization. Full article

(This article belongs to the Special Issue Reliability and Risk Analysis for Ships and Offshore Structures)

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21 pages, 12483 KB

Open AccessArticle

Fault Diagnosis Method for Marine Rotating Machinery Based on Particle Swarm Optimization-Driven Kernelized Cascade Forest

by Qingming Tan, Duankai Li, Jiawei Jiang and Kunxiang Ge

J. Mar. Sci. Eng. 2026, 14(17), 1585; https://doi.org/10.3390/jmse14171585 - 27 Aug 2026

Abstract

To address the problem of the fault mode discrimination accuracy of marine rotating machinery under the conditions of noise interference and limited training samples, a fault diagnosis method based on a particle swarm optimization-driven kernelized cascade forest is proposed. This method introduces RBF [...] Read more.

To address the problem of the fault mode discrimination accuracy of marine rotating machinery under the conditions of noise interference and limited training samples, a fault diagnosis method based on a particle swarm optimization-driven kernelized cascade forest is proposed. This method introduces RBF kernel mapping in the hierarchical structure of the cascade forest and uses PSO to conduct global optimization of the key parameters of the kernel function. Based on the marine fan test platform driven by a three-phase asynchronous motor, the frequency domain features are extracted as the model input, and the predicted probability distribution is utilized during the hierarchical training process. The experimental results show that in a noise-free environment and a noisy environment with Gaussian white noise, the test accuracy of the diagnostic accuracy rate is 98.05% and 97.10%, respectively, with a performance decrease of only 0.95%; it still maintains stable recognition accuracy under the condition of small samples, demonstrating superior small-sample learning ability compared to the benchmark method. Compared with the forest-based baseline method, the proposed method can reduce the performance degradation caused by noise and effectively improve the diagnostic performance of the model under noise and small-sample conditions, and this method may become a potential solution for fault intelligent diagnosis in marine rotating machinery. Full article

(This article belongs to the Section Ocean Engineering)

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20 pages, 6253 KB

Open AccessArticle

Coupled Bacterial and Microeukaryotic Community Turnover Across a Localized Dissolved Oxygen Reversal in the South China Sea

by Yaocheng Zou and Cui Guo

J. Mar. Sci. Eng. 2026, 14(17), 1584; https://doi.org/10.3390/jmse14171584 - 27 Aug 2026

Abstract

Vertical environmental gradients are important in structuring marine microbial communities, yet microbial responses to localized reversals within vertical environmental profiles remain less well resolved. We investigated bacterial and microeukaryotic plankton communities at ten depths between 5 and 250 m at station G4 in [...] Read more.

Vertical environmental gradients are important in structuring marine microbial communities, yet microbial responses to localized reversals within vertical environmental profiles remain less well resolved. We investigated bacterial and microeukaryotic plankton communities at ten depths between 5 and 250 m at station G4 in the northern South China Sea (SCS), with intensified sampling between 122 and 163 m around a localized subsurface dissolved oxygen (DO) reversal. Continuous CTD observations confirmed a reversal in the local DO–depth gradient within this interval. Bacterial and picoeukaryotic abundances peaked at the deep chlorophyll a maximum, while both bacterial and microeukaryotic communities exhibited clear depth-related changes in diversity and composition. Multivariate analyses showed that community variation was associated with a broader vertical environmental gradient involving temperature, salinity, density, nutrients, and chlorophyll a, whereas DO did not show a clear independent association after accounting for depth. Bacterial and microeukaryotic communities nevertheless exhibited broadly concordant vertical turnover. Taxonomically, surface waters were characterized by greater contributions from Cyanobacteriia and Dinophyceae, whereas deeper assemblages contained increased proportions of Gammaproteobacteria, Syndiniales, Polycystinea, and other subsurface-associated groups. Together, these observations suggest that the localized DO reversal occurred within a broader vertical environmental transition accompanied by coordinated changes in bacterial and microeukaryotic community structure. Full article

(This article belongs to the Section Marine Biology)

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28 pages, 4801 KB

Open AccessArticle

A Numerical Study on Hydrodynamic Performance and Propeller Design for Small Coastal Craft

by Soonhyun Lee, Hyungju Kim, Kwang-Jun Paik, Seong-Jin Eom and Sooyeon Kwon

J. Mar. Sci. Eng. 2026, 14(17), 1583; https://doi.org/10.3390/jmse14171583 - 27 Aug 2026

Abstract

Small coastal crafts are often equipped with stock propellers selected from limited commercial options, without detailed matching among the hull, main engine, reduction gear, and propeller. This study presents a practical and integrated procedure for evaluating propulsion performance and designing a propeller tailored [...] Read more.

Small coastal crafts are often equipped with stock propellers selected from limited commercial options, without detailed matching among the hull, main engine, reduction gear, and propeller. This study presents a practical and integrated procedure for evaluating propulsion performance and designing a propeller tailored to a G/T 4.99 coastal craft under the fully loaded departure condition. The CFD resistance simulations were validated against model test measurements of resistance, sinkage, and trim and were applied over a wide range of vessel speeds. Self-propulsion simulations were subsequently conducted to evaluate the propulsive characteristics of the target vessel. Based on the evaluated self-propulsion characteristics, actual engine specifications and propeller installation data from Korean coastal vessels were used to select the main engine and reduction gear and to define practical ranges for the propeller diameter and pitch ratio. An initial propeller was determined using the

B_{p} - δ

method, after which the mean pitch ratio was iteratively corrected through full-scale performance prediction. The final propeller was selected by matching the predicted rotational speed under the trial condition to the target value determined by the engine and reduction gear while confirming the attainable vessel speed under the service condition with a 15% sea margin. The final propeller was evaluated through CFD self-propulsion simulations and compared with the stock propeller. At 16 and 18 knots, the designed propeller increased the overall propulsive efficiency by 8.4% and 10.1%, respectively, while reducing the required delivered power by 7.8% and 9.2%. These results demonstrate that the proposed procedure can improve the matching among the hull, machinery, and propeller and provide a practical basis for designing efficient propellers for small coastal crafts. Full article

(This article belongs to the Special Issue Marine Propulsion Systems: Hydrodynamics, Numerical Simulation, and Intelligent Control)

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13 pages, 3549 KB

Open AccessArticle

Bleaching Dynamics of Crustose Coralline Algae in Jeju Island, Korea

by Kyeong-Tae Lee, Myung Sook Kim, Jong-Seop Shin, Yeong-Ji Park and Hyun-Sung Yang

J. Mar. Sci. Eng. 2026, 14(17), 1582; https://doi.org/10.3390/jmse14171582 - 27 Aug 2026

Abstract

Crustose coralline algae (CCA) are key reef-building organisms, yet their bleaching dynamics and associated environmental factors in natural ecosystems remain poorly understood. This is particularly relevant to Jeju Island, Korea, where declines in canopy-forming macroalgae and the expansion of CCA-dominated barren grounds are [...] Read more.

Crustose coralline algae (CCA) are key reef-building organisms, yet their bleaching dynamics and associated environmental factors in natural ecosystems remain poorly understood. This is particularly relevant to Jeju Island, Korea, where declines in canopy-forming macroalgae and the expansion of CCA-dominated barren grounds are reshaping benthic communities, highlighting the need to monitor how CCA respond to environmental stress. In this study, bleaching dynamics were monitored monthly using Autonomous Reef Monitoring Structures (ARMS) deployed at Bomok, southern Jeju Island, Korea, during a 13-month period (August 2022–August 2023). Total CCA cover, bleached CCA cover, and bleached CCA ratio were quantified and compared with seawater temperature and daytime light intensity. Despite persistently high total CCA cover, the bleached CCA ratio varied markedly over time, with multiple peaks and subsequent declines, reaching a maximum of 65.8%. The bleached CCA ratio was positively correlated with daytime light intensity (ρ = 0.709, p = 0.015), whereas no significant association was detected with seawater temperature. Nine bleached specimens were assigned to the genus Porolithon based on psbA phylogenetic analysis, representing the first molecular identification of bleached CCA from Korea. These findings provide a temporal baseline for understanding CCA bleaching within the rapidly changing benthic communities of Jeju Island and indicate that light intensity may be an important environmental correlate of bleaching. Full article

(This article belongs to the Special Issue How Marine Environment Changes Affect Marine Organism's Responses)

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26 pages, 15710 KB

Open AccessArticle

Nonparametric and Parametric Modeling of Hydrodynamics for a Fully Appended Autonomous Underwater Vehicle

by Yingjie Guan, Xiaoyang Deng, Yougang Bian, Xuan Zeng, Xiaojun Zhuo and Xu Liu

J. Mar. Sci. Eng. 2026, 14(17), 1581; https://doi.org/10.3390/jmse14171581 - 26 Aug 2026

Abstract

Hydrodynamic models underpin Autonomous Underwater Vehicle (AUV) design, motion control, and performance evaluation. Existing methods face two critical bottlenecks: (1) conventional explicit CFD requires predefined trajectories, which fails to capture true motion responses under combined rudder-propeller action and creates a disconnect between simulation [...] Read more.

Hydrodynamic models underpin Autonomous Underwater Vehicle (AUV) design, motion control, and performance evaluation. Existing methods face two critical bottlenecks: (1) conventional explicit CFD requires predefined trajectories, which fails to capture true motion responses under combined rudder-propeller action and creates a disconnect between simulation and real operations; (2) the widely adopted Standard Submarine Motion Equations (SSME) suffer from high parameter redundancy, while high-precision non-parametric models incur prohibitive computational costs, hindering embedded deployment. To address these gaps, this paper proposes an implicit CFD-driven framework for fully appended AUVs equipped with through-body thrusters. It requires no preset trajectories, directly coupling periodic propeller thrust and rudder angle excitations to achieve 5-degree-of-freedom (5DOF) spatial motion simulations aligned with real navigation states. Parametric and non-parametric models are identified via Least Squares (LS) and Neural Networks (NN), respectively. Sobol global sensitivity analysis reduces SSME dimensionality, yielding a Basic Submarine Motion Equation (BSME) with only 25 key parameters—cutting the parameter count by 55% with negligible accuracy loss. Validation shows the non-parametric NN model reduces prediction error by over 10% compared to its parametric counterpart, while the streamlined BSME enables real-time forecasting in low-power computing scenarios. This approach balances accuracy and efficiency for rapid hydrodynamic prediction during early AUV design and embedded controller deployment. Full article

(This article belongs to the Section Ocean Engineering)

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27 pages, 2221 KB

Open AccessArticle

Effects of Hull Form and Propulsion Power Characteristics on the Maneuvering Performance of Large Fishing Vessels

by Su-Hyung Kim and Min-Gyu Lee

J. Mar. Sci. Eng. 2026, 14(17), 1580; https://doi.org/10.3390/jmse14171580 - 26 Aug 2026

Abstract

The maneuverability standards established by the International Maritime Organization (IMO) primarily address merchant ships, while large fishing vessels generally fall outside their scope. This study investigated the relationships between selected design characteristics and maneuvering performance using full-scale trial data from four large fishing [...] Read more.

The maneuverability standards established by the International Maritime Organization (IMO) primarily address merchant ships, while large fishing vessels generally fall outside their scope. This study investigated the relationships between selected design characteristics and maneuvering performance using full-scale trial data from four large fishing vessels. Their principal design characteristics and maneuvering indices were compared with the distributions of a 226-ship merchant-ship database and with four reference merchant ships for which complete design and trial data were available. The fishing-vessel cases were positioned toward the lower ranges of the available merchant-ship distributions for L/B and C_b/(L/B), whereas their B/d values substantially overlapped the principal merchant-ship range. Their P/Δ values were higher than those of the four reference merchant ships. Within the four fishing-vessel cases, B/d and P/Δ showed the most apparent tendencies with the Turning indices, L/B and C_b with the Zig-zag Overshoot angles, and C_b and P/Δ with Track reach/L. These observations indicate that the design variables associated with the most apparent tendencies differed among turning, course-checking, and stopping responses. Although the limited dataset does not permit statistical generalization or the establishment of causal relationships, the results suggest that the maneuvering characteristics of large fishing vessels are better characterized by considering combined hull-form and propulsion characteristics together with the balance among multiple maneuvering responses, rather than by interpreting individual design variables in isolation. These full-scale observations provide a basis for further systematic investigation and maneuverability assessment of large fishing vessels. Full article

(This article belongs to the Section Ocean Engineering)

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39 pages, 48413 KB

Open AccessReview

Effects of Seabed Scour on the Structural Performance and Safety of Fixed-Bottom Offshore Wind Turbine Foundations: A Review

by Zhongchao Zhou, Mohd Yuhyi Mohd Tadza and Zhisheng Zhou

J. Mar. Sci. Eng. 2026, 14(17), 1579; https://doi.org/10.3390/jmse14171579 - 26 Aug 2026

Abstract

Offshore wind power has expanded rapidly in recent decades and is expected to continue growing through the deployment of larger turbines in deeper waters. The safe and stable operation of offshore wind turbines (OWTs) depends critically on foundation performance, which is severely threatened [...] Read more.

Offshore wind power has expanded rapidly in recent decades and is expected to continue growing through the deployment of larger turbines in deeper waters. The safe and stable operation of offshore wind turbines (OWTs) depends critically on foundation performance, which is severely threatened by seabed scour. To better understand these threats, this paper reviews recent studies on the effects of seabed scour on the structural performance and safety of fixed-bottom offshore wind turbine foundations (OWTFs), focusing on four aspects: (1) the changes induced by scour in both the seabed morphology and the soil mechanical state, which form the basis for the subsequent analyses; (2) the effects of scour on the bearing capacity and natural frequency of the foundation, covering both its static and dynamic performance; (3) the behavior of scoured foundations under long-term cyclic loading during normal operation and under transient seismic action during extreme events; and (4) the role of scour protection in enhancing structural safety. Several future research directions are also highlighted. This review offers helpful insights for assessing scour-induced risk and for designing scour protection from a structural safety perspective, thereby supporting the safe operation of OWTs. Full article

(This article belongs to the Section Ocean Engineering)

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17 pages, 11918 KB

Open AccessArticle

Spatiotemporal Evolution and Driving Mechanisms of Ecological Vulnerability in Guangdong Haifeng Ramsar Site, China

by Chu Xie, Ting Yang, Ruotong Qu, Qing Xiao, Changjun Gao and Kunshan Bao

J. Mar. Sci. Eng. 2026, 14(17), 1578; https://doi.org/10.3390/jmse14171578 - 26 Aug 2026

Abstract

The Guangdong Haifeng Coastal Wetlands (Ramsar Site No. 1727) in Shanwei City are a critical habitat for migratory birds, but the long-term evolution and driving mechanisms of ecological vulnerability under rapid urbanization remain insufficiently understood. In particular, few studies have quantitatively characterized the [...] Read more.

The Guangdong Haifeng Coastal Wetlands (Ramsar Site No. 1727) in Shanwei City are a critical habitat for migratory birds, but the long-term evolution and driving mechanisms of ecological vulnerability under rapid urbanization remain insufficiently understood. In particular, few studies have quantitatively characterized the temporal shifts in the relative roles of anthropogenic pressures and conservation policies over decadal scales. This study developed a landscape pattern-based ecological vulnerability assessment model integrating spatial autocorrelation, Geodetector, the PLUS model, and spatial overlay analysis to diagnose the dynamics and driving mechanisms of the wetlands from 1980 to 2018. The results showed that farmland and woodland dominated Shanwei City, while water bodies consistently dominated the Haifeng Wetlands. Ecological vulnerability exhibited significant spatial heterogeneity, with levels higher in the northwest and lower in the southeast. Forest and water expansion overlapped with vulnerability reduction, whereas built-up and farmland expansion matched increases in vulnerability. Land-use intensity, elevation, and mean annual temperature were identified as the primary drivers. The drivers of built-up land expansion shifted from population-related pressures during 1980–2000 to stronger policy regulation effects after 2000, indicating a transition in human–land interactions. Conservation policies, including nature reserve establishment and Ramsar designation, provided important institutional support for ecological management. These findings highlight the importance of integrating long-term land-use dynamics with natural, socioeconomic and policy contexts to improve the understanding and management of coastal wetlands vulnerability under rapid urbanization. Full article

(This article belongs to the Special Issue Morphological Changes in the Coastal Ocean)

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18 pages, 8483 KB

Open AccessArticle

Prediction on the Suitable Habitat Change of Balaenoptera in Pacific Polymetallic Nodule Areas Based on the MaxEnt Model

by Jiayi Sun, Wenquan Zhang, Ailian Hu, Chengbing Song and Juan Yang

J. Mar. Sci. Eng. 2026, 14(17), 1577; https://doi.org/10.3390/jmse14171577 - 26 Aug 2026

Abstract

With increasing global demand for deep-sea resources, polymetallic nodule mining has become a potential approach for accessing critical minerals. To identify potential areas of ecological concern associated with future deep-sea mining activities, this study predicted the suitable habitat distribution of Balaenoptera species in [...] Read more.

With increasing global demand for deep-sea resources, polymetallic nodule mining has become a potential approach for accessing critical minerals. To identify potential areas of ecological concern associated with future deep-sea mining activities, this study predicted the suitable habitat distribution of Balaenoptera species in the Pacific polymetallic nodule areas using the Maximum Entropy Model (MaxEnt). The results showed that environmental variables, such as temperature, salinity, and chlorophyll-a concentration, were the major contributors to Balaenoptera habitat suitability, with their combined contribution exceeding 70% across four species. Temperature showed the highest contribution to habitat suitability predictions for B. acutorostrata, B. edeni, and B. physalus, with contribution values of 38.2%, 46.4%, and 45.4%, respectively. In contrast, salinity contributed the highest (38.4%) to the habitat suitability of B. musculus. Moreover, future climate scenarios posed different changes in the predicted suitable habitats for different Balaenoptera species. Under the current climate scenario, a large proportion of suitable habitat (PSH) were affected in the eastern Pacific mining areas, including 8.52% for B. acutorostrata, 54.94% for B. edeni, 53.73% for B. musculus, and 20.74% for B. physalus. Under future climate scenarios, the PSH of B. acutorostrata and B. musculus showed an increasing trend, which was especially pronounced under the SSP1-2.6 climate scenario (3.96% and 17.27% respectively); while B. edeni showed opposite trends, with a decrease (−6.14%) under SSP1-2.6 and an increase (4.91%) under SSP5-8.5 scenario. The PSH of B. physalus showed a slight decrease (−0.43% and −0.32%) under both scenarios. These findings may support future environmental management and impact assessment for deep-sea polymetallic nodule exploitation. Full article

(This article belongs to the Special Issue Advances in Ecological Modelling of Marine Mammal Habitats of Importance)

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29 pages, 12034 KB

Open AccessReview

A Critical Review of Platform Motion Effects on the Aerodynamic Performance, Wake Dynamics and Load Responses of Floating Vertical Axis Wind Turbines

by Haoda Huang, Qingsong Liu, Chun Li, Wanfu Zhang, Musa Bashir and Gregorio Iglesias

J. Mar. Sci. Eng. 2026, 14(17), 1576; https://doi.org/10.3390/jmse14171576 - 26 Aug 2026

Abstract

Floating vertical-axis wind turbines (VAWTs) couple intrinsically unsteady rotor aerodynamics with the motions of their supporting platforms, producing complex temporal variations in power output, aerodynamic loads, and wake transport. A structured search of the Web of Science Core Collection and Scopus, supplemented by [...] Read more.

Floating vertical-axis wind turbines (VAWTs) couple intrinsically unsteady rotor aerodynamics with the motions of their supporting platforms, producing complex temporal variations in power output, aerodynamic loads, and wake transport. A structured search of the Web of Science Core Collection and Scopus, supplemented by citation tracking, identified peer-reviewed studies published from database inception to 30 June 2026. The reviewed computational fluid dynamics (CFD) studies were classified as decoupled or fully coupled according to whether bidirectional feedback between the flow field and platform response was resolved. The evidence shows that motion-induced velocities alter blade-relative inflow and effective angle of attack, thereby modifying dynamic stall, loads, and wake evolution. Scaled testing is limited by the incompatibility between Froude and Reynolds similitude. Under identical pitch conditions, the mean power coefficient increased by 16.42% at full scale but decreased by 56.71% at 1:100 scale. Platform motion generally increases power and load fluctuations but may accelerate wake recovery; effects on mean performance remain configuration- and scale-dependent, so no universally optimal rotor-platform design has emerged. Overall, this review provides an integrated understanding of the effects of platform motion on the unsteady aerodynamics, load responses, and wake evolution of floating VAWTs, and clarifies the applicability of decoupled and fully coupled CFD methods to mechanism identification and system-level assessment. Full article

(This article belongs to the Special Issue Coupled Dynamics and Resilience of Floating Offshore Renewable Energy Systems)

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28 pages, 6389 KB

Open AccessArticle

A Simplified Sequential Coupled Simulation Framework for Floating Offshore Wind Turbines: A Case Study of a 15 MW TLP Turbine

by Hongda Zhang, Rui Zhang, Shuyu Yan, Le Qi, Yong Wang, Jinbo Chen, Yan Bao and Hongbo Zhu

J. Mar. Sci. Eng. 2026, 14(17), 1575; https://doi.org/10.3390/jmse14171575 - 26 Aug 2026

Abstract

Tension-leg platform (TLP) horizontal-axis wind turbines (TLP-HAWTs) have become increasingly important in deep-water offshore wind energy development. However, their performance is strongly affected by coupled platform motions induced by wind and wave loads, making fully coupled simulations a critical prerequisite for accurate performance [...] Read more.

Tension-leg platform (TLP) horizontal-axis wind turbines (TLP-HAWTs) have become increasingly important in deep-water offshore wind energy development. However, their performance is strongly affected by coupled platform motions induced by wind and wave loads, making fully coupled simulations a critical prerequisite for accurate performance assessment. Conventional fully coupled approaches often struggle to balance computational efficiency and numerical fidelity. In this study, a simplified sequential coupled modeling framework is proposed based on the commercial solvers OrcaFlex and STAR-CCM+. In this framework, OrcaFlex is employed to simulate the hydrodynamic response of the floating platform, and the resulting platform motions are subsequently imposed as prescribed inputs in high-fidelity CFD-based aerodynamic simulations. Based on the proposed framework, a series of case studies of a 15 MW TLP-HAWT are conducted to investigate the effects of wind-induced and wave-induced platform motions on aerodynamic performance. The results indicate that wind-induced platform motions have a negligible impact on local inflow conditions and vortex intensity, and their influence on mean blade loads and wake topology can be safely ignored under rated conditions. In contrast, wave-induced motions significantly enhance unsteady aerodynamic loads, intensify vortex shedding, alter torque distribution along the blades, and increase wake turbulence intensity as well as velocity deficit. These findings suggest that wave-induced platform dynamics dominate the unsteady aerodynamic response and wake evolution of TLP-HAWTs under rated conditions, while wind-induced motions play a secondary role. The results provide valuable insights for reduced-order modeling, control strategy development, and the design optimization of efficient floating offshore wind turbines. Full article

(This article belongs to the Section Marine Energy)

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20 pages, 7400 KB

Open AccessArticle

Lateral-Loading Response of an Offshore Wind Turbine Tetrapod Piled Jacket Foundation Considering Local Scour-Hole Morphology

by Minsi Liang, Zhijie Ding, Hanbo Zheng, Panpan Shen, Aiwu Yang and Hao Zhang

J. Mar. Sci. Eng. 2026, 14(17), 1574; https://doi.org/10.3390/jmse14171574 - 25 Aug 2026

Abstract

Tetrapod piled jacket foundations, widely adopted for large-capacity offshore wind turbines, are frequently affected by scour, which substantially alters their lateral mechanical responses. Nevertheless, existing studies on this subject remain limited and mostly adopt simplified uniform scour assumptions that deviate significantly from actual [...] Read more.

Tetrapod piled jacket foundations, widely adopted for large-capacity offshore wind turbines, are frequently affected by scour, which substantially alters their lateral mechanical responses. Nevertheless, existing studies on this subject remain limited and mostly adopt simplified uniform scour assumptions that deviate significantly from actual field conditions. This study conducted lateral-loading model tests on scoured tetrapod piled jacket foundations, with the local scour geometry idealized based on the non-uniform scour-hole morphology reported in field monitoring and flume test studies. The evolution law of the lateral bearing capacity of the foundations with scour development is revealed, and the differences in lateral bearing performance under uniform and non-uniform scour are systematically compared. A three-dimensional finite element model is established and validated against test data to verify its accuracy and reliability. Additionally, comprehensive parametric analyses are performed to supplement the experimental results, exploring the influences of flow angles, corresponding scour-hole morphologies and lateral load directions on the lateral bearing performance of tetrapod piled jacket foundations. The pile bearing mechanism and internal force distribution characteristics are further clarified. The research findings can provide a theoretical basis for the safe service of offshore wind turbines supported by tetrapod piled jacket foundations. Full article

(This article belongs to the Section Ocean Engineering)

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27 pages, 7023 KB

Open AccessArticle

Bearing Voltage Prediction-Based Selective NLM Correction for EDM Suppression in Marine MMC Propulsion Drives

by Sungwoo Song, Heemoon Kim, Jongsu Kim, Seongwan Kim and Hyeonmin Jeon

J. Mar. Sci. Eng. 2026, 14(17), 1573; https://doi.org/10.3390/jmse14171573 - 25 Aug 2026

Abstract

Bearing damage caused by electric discharge machining (EDM) is a concern in electric ship propulsion drives, particularly during low-speed operations such as maneuvering and slow steaming. In a modular multilevel converter (MMC) operated with nearest-level modulation (NLM), rounding of the three-phase submodule insertion [...] Read more.

Bearing damage caused by electric discharge machining (EDM) is a concern in electric ship propulsion drives, particularly during low-speed operations such as maneuvering and slow steaming. In a modular multilevel converter (MMC) operated with nearest-level modulation (NLM), rounding of the three-phase submodule insertion numbers produces a residual imbalance that appears as common-mode voltage (CMV) and charges the bearing film capacitance. The peak bearing voltage rises from 6.4 V at 60 Hz to 20.0 V at 10 Hz, while the thinning lubricant film lowers the dielectric breakdown threshold. Always-on CMV reduction approaches apply a corrected switching candidate in every control period, including intervals where the bearing voltage stays well below the threshold. This paper proposes a selective NLM correction driven by predicted bearing voltage risk: a reduced-order RC model predicts the bearing voltage the conventional NLM candidate would produce, and a hysteretic controller applies a zero-CMV candidate only when that prediction approaches the insulation threshold. Using a worst-case discharge criterion and thresholds of 5.9–29 V derived from elastohydrodynamic film thickness estimates, simulations at 10 Hz show that the method eliminates EDM events over the full evaluated threshold range. It achieves the same zero-EDM outcome as always-on correction while reducing the correction mode activation ratio from 100% to at most 30.8%, and remains inactive where conventional NLM is already safe. Full article

(This article belongs to the Special Issue Marine Propulsion Systems: Hydrodynamics, Numerical Simulation, and Intelligent Control)

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19 pages, 3250 KB

Open AccessArticle

Optimization and Analysis of a Long-Arm Intelligent Marine Sampling Platform

by Heng Zhou, Lejingyi Zhou, Haibo Wu, Minghao Xu, Lindan Zhang, Jia Guo, Wei Fu, Hengchi Zheng and Tian Ni

J. Mar. Sci. Eng. 2026, 14(17), 1572; https://doi.org/10.3390/jmse14171572 - 25 Aug 2026

Abstract

As the core equipment for in situ deep-sea scientific research, the design quality and operational performance of the sampling platform determine the efficiency of deep-sea operations, including long-term continuous observation, high-quality sampling and preservation, and in situ experimental studies. To address technical bottlenecks [...] Read more.

As the core equipment for in situ deep-sea scientific research, the design quality and operational performance of the sampling platform determine the efficiency of deep-sea operations, including long-term continuous observation, high-quality sampling and preservation, and in situ experimental studies. To address technical bottlenecks commonly observed in conventional platforms, including track sinkage, excessive motion drag, and low propulsion efficiency, this study proposes the design and development of a novel sampling platform with tracked-propeller dual-mode propulsion, deployable from either a surface vessel or a large manned submersible, capable of high-throughput, multi-sequence fidelity water sampling, in situ sediment incubation, and seabed mudstone sampling in deep sea. Through hydrodynamic performance analysis and design optimization, both lightweight design and drag reduction were achieved. Furthermore, load verification of the main frame under multiple operating conditions was conducted; results demonstrate that the structure meets strength and stiffness requirements and ensures reliability in typical service environments. This study provides a theoretical basis and technical reference for the development of similar deep-sea sampling platforms and holds substantial engineering application value. Full article

(This article belongs to the Special Issue Overall Design of Underwater Vehicles)

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