Journal of Marine Science and Engineering

24 pages, 3467 KB

Open AccessArticle

A Multi-Ship Intelligent Collision Avoidance Decision Method Considering Intention Uncertainty

by Zhipeng Wan, Langxiong Gan, Yaqing Shu and Lei Zhang

J. Mar. Sci. Eng. 2026, 14(17), 1658; https://doi.org/10.3390/jmse14171658 (registering DOI) - 6 Sep 2026

A collision avoidance decision-making method that integrates intention recognition with predictive risk perception is proposed to address the uncertainty and dynamic complexity of multi-ship encounters. First, the probabilities of avoidance maneuvers are derived from COLREGs and maritime practice to establish predictive distributions of [...] Read more.

A collision avoidance decision-making method that integrates intention recognition with predictive risk perception is proposed to address the uncertainty and dynamic complexity of multi-ship encounters. First, the probabilities of avoidance maneuvers are derived from COLREGs and maritime practice to establish predictive distributions of course alterations. Second, an avoidance-maneuver intention (AMI) confidence coefficient is formulated from evidence fused using Dempster–Shafer (DS) evidence theory to quantify the reliability of the target ship’s maneuver behavior. Third, a predictive risk-perception-based line-of-sight (PRP-LOS) method is developed by introducing a predicted-equivalent virtual ship position into a navigation risk field. Simulation results show that the proposed method accurately infers target-ship AMIs and effectively reduces collision risk while balancing safety and smoothness. These research results provide effective methodological support for improving autonomous decision-making capabilities. Full article

(This article belongs to the Section Ocean Engineering)

29 pages, 12997 KB

Open AccessArticle

Cross-Estuary Generalization of Color Front Identification Using DenseNet-121

by Yumeng Tian, Luanbin Yin, Wenzhou Wu, Peng Zhang and Huiping Jiang

J. Mar. Sci. Eng. 2026, 14(17), 1657; https://doi.org/10.3390/jmse14171657 (registering DOI) - 6 Sep 2026

Abstract

Remote identification of color fronts, defined as transition zones with sharp gradients in water optical properties, has suffered from non-transferable thresholds, severe areal over-detection, and weak cross-estuary generalization. To address these issues, we propose a framework that integrates multi-scale spectral–spatial features with DenseNet-121. [...] Read more.

Remote identification of color fronts, defined as transition zones with sharp gradients in water optical properties, has suffered from non-transferable thresholds, severe areal over-detection, and weak cross-estuary generalization. To address these issues, we propose a framework that integrates multi-scale spectral–spatial features with DenseNet-121. We constructed a 165-D vector, seven window scales (three × three to 15 × 15) × two statistical descriptors (means and standard deviations) × 11 bands + 11 bands, then rearranged it into a 3D tensor and resized it to a 2D image for DenseNet-121 transfer learning with red-band post-processing. On in-distribution tests, the model achieves 0.953 accuracy, 0.953 F1, outperforming random forest. Cross-estuary generalization yields a mean F1 (0.744). Performance varies with optical compatibility: the Mississippi (runoff-dominated) gives the best F1 (0.874), while the Pearl (multi-channel, runoff-tide co-controlled) drops to 0.607 due to heterogeneity and reversed reflectance patterns. The red-band constraint can help reduce areal false alarms and improve spatial coherence of frontal regions, but its effectiveness depends on optical separability. The output width reflects superposition of transition zone and window scale. We demonstrate the potential and boundary conditions of this approach for cross-estuary color front identification, offering insights for physically consistent and generalizable ocean color monitoring. Full article

(This article belongs to the Section Physical Oceanography)

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19 pages, 3849 KB

Open AccessArticle

Influence of Horn-Type Cavity Acoustic Coatings on the Error of Force–Sound Reciprocity Testing for Underwater Structures

by Tao Peng, Rongwu Xu, Zilong Peng, Jiarui Zhang, Jinwei Liu and Suchen Xu

J. Mar. Sci. Eng. 2026, 14(17), 1656; https://doi.org/10.3390/jmse14171656 (registering DOI) - 6 Sep 2026

Abstract

Accurate measurement of vibro-acoustic transfer functions is essential for ship noise control. Because direct testing requires high-power excitation sources that are difficult and costly to deploy, the reciprocity method has attracted increasing attention. Its application to full-scale ships, however, has long been hindered [...] Read more.

Accurate measurement of vibro-acoustic transfer functions is essential for ship noise control. Because direct testing requires high-power excitation sources that are difficult and costly to deploy, the reciprocity method has attracted increasing attention. Its application to full-scale ships, however, has long been hindered by an unresolved theoretical question: whether hull-mounted acoustic coatings compromise force–sound reciprocity. To answer this question, this study combines theoretical analysis, numerical simulation, and anechoic water-tank experiments to investigate a typical horn-type cavity acoustic coating. Theoretical analysis shows that, because its complex stiffness tensor remains symmetric, a linear viscoelastic coating with geometrically asymmetric cavities still preserves reciprocity. Numerical simulations of a stiffened double-layer cylindrical shell covered with the coating show that the forward and reciprocal transfer functions coincide to well within 1 dB over the entire computed band. Anechoic water-tank experiments on a scaled model show that applying the coating raises the band-averaged reciprocity error by only 0.2 dB, from 1.4–1.5 dB to 1.6–1.7 dB in the 2–5 kHz band. These results provide evidence that, for the tested coating and structural configuration under anechoic conditions, the horn-cavity coating introduces no significant principle-based error into reciprocity testing—a first quantitative step towards removing the long-standing theoretical obstacle to applying reciprocity methods to coated, full-scale ships. Full article

(This article belongs to the Section Ocean Engineering)

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20 pages, 4189 KB

Open AccessArticle

The Effects of Seawater on the Durability of Planks in Withstanding Ram Attacks: Experimental Archaeology

by Elhanan Itzhack, Deborah Cvikel, Mark Cavanagh and Yoav Me-Bar

J. Mar. Sci. Eng. 2026, 14(17), 1655; https://doi.org/10.3390/jmse14171655 (registering DOI) - 6 Sep 2026

Abstract

The present paper constitutes the second phase of a three-phase research project and focuses on the experimental determination of the Modulus of Elasticity (MoE), a fundamental material property. It builds on a previous study published in 2024, which developed an analytical model for [...] Read more.

The present paper constitutes the second phase of a three-phase research project and focuses on the experimental determination of the Modulus of Elasticity (MoE), a fundamental material property. It builds on a previous study published in 2024, which developed an analytical model for estimating the minimum velocity required for an ancient warship to inflict significant damage on an opposing vessel through ramming. The MoE, together with several other parameters, plays a critical role in determining the ability of hull planks to withstand the forces generated during such attacks. For wood, MoE is influenced by species, moisture content, and growth conditions. However, published MoE values are typically obtained under controlled moisture conditions and do not represent seawater-saturated wood, which is directly relevant to submerged ship planks. To address this gap, the MoE of cedar (Cedrus libani), fir (Abies alba), and pine (Pinus spp.), was experimentally determined using three-point bending tests after one week of immersion in East Mediterranean seawater. The resulting MoE values provide representative mechanical properties for the analytical model developed in this study. Incorporating the experimentally determined MoE values into the analytical model of one trireme ramming another yields an estimated minimum impact velocity range of about 1.0–1.2 m/s, required for a ram to cause a catastrophic fracture of a single seawater-soaked plank. Full article

(This article belongs to the Section Ocean Engineering)

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26 pages, 15009 KB

Open AccessArticle

Coastal Vulnerability of the Macrotidal and Heavily Engineered Coast in Fujian, China

by Junhui Chen, Fei Tang and Heshan Lin

J. Mar. Sci. Eng. 2026, 14(17), 1654; https://doi.org/10.3390/jmse14171654 (registering DOI) - 5 Sep 2026

Abstract

Fujian has one of China’s most tide-dominated and heavily engineered coasts, yet no segment-scale vulnerability assessment exists. We assessed 2449 km of mainland shoreline in 1 km segments using the classic six-variable coastal vulnerability index, from public data. Change rates came from thirty [...] Read more.

Fujian has one of China’s most tide-dominated and heavily engineered coasts, yet no segment-scale vulnerability assessment exists. We assessed 2449 km of mainland shoreline in 1 km segments using the classic six-variable coastal vulnerability index, from public data. Change rates came from thirty annual Landsat-based shorelines, giving a complete index for 2293 segments. The very high vulnerability class (defined by provincial quartiles) is predominantly concentrated in Putian (51.9 percent) and Quanzhou (42.8 percent). Those differences follow shoreline type. Eighty percent of the remaining 115 km of sandy shore is very high, against 53 percent of rocky shore in the low class. An exact decomposition gives each segment a dominant contributor from tide in Ningde to waves in Zhangzhou. Thirty percent of the 1.70 million people within 1 km of the coast live behind the very high quarter. Eleven sensitivity runs move individual segments, but none breaks the link to shoreline type, and Putian and Quanzhou lead even without the rate variable. The two published conventions for scoring tidal range rank different prefectures first, and each matches a different hazard. The storm-framed convention leads with Zhangzhou, where 99.7 percent of the province’s 2020 storm-surge damage fell. Full article

(This article belongs to the Section Coastal Engineering)

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17 pages, 1245 KB

Open AccessArticle

Time-Dependent Reliability Analysis of Bridge Piers for Cross-Sea Bridges Based on Dynamic Bayesian Networks

by Laixiang Xu, Jun Cheng, Zhidong Liu, Zhihui Zhou, Xiao Ning, Xinyuan Liu and Tian Zhang

J. Mar. Sci. Eng. 2026, 14(17), 1653; https://doi.org/10.3390/jmse14171653 (registering DOI) - 5 Sep 2026

Abstract

To accurately assess the time-dependent reliability of bridge piers in marine environments, this paper proposes a time-dependent reliability evaluation method for bridge piers based on a Dynamic Bayesian Network (DBN). By establishing a resistance degradation model under the combined effects of reinforcement corrosion [...] Read more.

To accurately assess the time-dependent reliability of bridge piers in marine environments, this paper proposes a time-dependent reliability evaluation method for bridge piers based on a Dynamic Bayesian Network (DBN). By establishing a resistance degradation model under the combined effects of reinforcement corrosion and concrete deterioration and embedding it into the DBN framework, dynamic prediction and updating of pier time-dependent reliability are achieved. A case study of a twin-column pier was conducted for verification, showing that the computational results of the proposed DBN model align well with the first-order reliability method (FORM), validating its accuracy and feasibility in time-dependent reliability prediction. Further, using the most severe service condition, that is, the tidal-spray zone as an example, the DBN prediction results were updated with inspection data to achieve dynamic assessment of the actual pier lifespan. Additionally, a comparative analysis of environmental zones revealed that the tidal-spray zone exhibits the fastest reliability degradation, followed by the atmospheric zone, while the submerged zone shows the slowest. Full article

(This article belongs to the Section Ocean Engineering)

19 pages, 732 KB

Open AccessArticle

Flow Due to a Uniform Distribution of Pulsating Sources or Dipoles over a Flat Triangle Steadily Advancing in Calm Water

by Francis Noblesse and Jiayi He

J. Mar. Sci. Eng. 2026, 14(17), 1652; https://doi.org/10.3390/jmse14171652 (registering DOI) - 5 Sep 2026

Abstract

This study considers the Fourier component in the basic Rankine–Fourier decomposition of the flows created by pulsating sources and dipoles (with time-harmonic strength) uniformly distributed over a general flat triangle that steadily advances in calm deep water. The Fourier potentials related to these [...] Read more.

This study considers the Fourier component in the basic Rankine–Fourier decomposition of the flows created by pulsating sources and dipoles (with time-harmonic strength) uniformly distributed over a general flat triangle that steadily advances in calm deep water. The Fourier potentials related to these basic flows are decomposed into a wave component defined by a single (one-fold) Fourier integral of an elementary exponential/trigonometric wave function, and a local-flow component defined by a single Fourier integral of the logarithmic function and the complex exponential integral function. These single Fourier integral representations of the waves and the local flows created by sources or dipoles distributed over a general flat triangle do not involve approximations, i.e., are exact, and are simple and well suited for reliable and practical numerical evaluation. Full article

(This article belongs to the Section Ocean Engineering)

22 pages, 1502 KB

Open AccessArticle

Efficiency-Consensus-Based Multi-Agent Power-Distribution Strategy for ISOP LLC-DAB Hybrid Converters in Shipboard DC Power Systems

by Yuefeng Liao, Jiarui Dong, Xiao Han, Duo Yang and Xiaoxue Wan

J. Mar. Sci. Eng. 2026, 14(17), 1651; https://doi.org/10.3390/jmse14171651 - 4 Sep 2026

Abstract

Multi-module DC–DC converters are well suited to shipboard DC power systems with stringent requirements for high power density, operational safety, and continuous power supply. By distributing the system voltage, current, and power among multiple submodules (SMs), the modular architecture reduces device stresses and [...] Read more.

Multi-module DC–DC converters are well suited to shipboard DC power systems with stringent requirements for high power density, operational safety, and continuous power supply. By distributing the system voltage, current, and power among multiple submodules (SMs), the modular architecture reduces device stresses and facilitates capacity expansion, maintenance, and redundant operation. Among the available modular configurations, the input-series output-parallel (ISOP) structure is particularly suitable for interfacing high-voltage DC buses with low-voltage, high-current loads. However, conventional voltage- or current-sharing strategies generally neglect efficiency differences among SMs. Under equal power sharing, low-efficiency SMs generate greater losses and experience higher thermal stress, resulting in thermal imbalance and accelerated aging. To address this issue, an efficiency-consensus-based power-distribution strategy is proposed for ISOP LLC-DAB hybrid converters. A distributed efficiency observer based on multi-agent consensus theory dynamically regulates the power references according to the relative efficiencies of the SMs, allowing high-efficiency modules to process more power while reducing the loading of low-efficiency modules. Experimental results obtained from a three-module prototype include comparative efficiency measurements and temperature-distribution tests. The results demonstrate that the proposed strategy improves the efficiency consistency among the three SMs, redistributes power according to their relative efficiency states, and reduces the temperature difference among the modules, thereby mitigating localized loss concentration and thermal imbalance. The proposed method provides a feasible solution for improving the electrothermal operating conditions of modular DC–DC converters. The achieved reduction in thermal imbalance may contribute to enhanced long-term reliability by alleviating uneven electrothermal stress. Full article

(This article belongs to the Special Issue Advancements in Hybrid Power Systems for Marine Applications)

32 pages, 1314 KB

Open AccessArticle

PGCFlow: Observation-Grounded Conditional Ensemble Generation of Spaceborne GNSS-R BRCS Delay–Doppler Maps

by Weimin Chen, Dongmei Song and Bin Wang

J. Mar. Sci. Eng. 2026, 14(17), 1650; https://doi.org/10.3390/jmse14171650 (registering DOI) - 4 Sep 2026

Abstract

Spaceborne Global Navigation Satellite System Reflectometry (GNSS-R) archives usually provide only one delay–Doppler map (DDM) for each recorded observation condition, limiting the representation of residual DDM variability. This study proposes a Position-Guided Conditional Normalizing Flow (PGCFlow) for observation-grounded probabilistic expansion of ocean bistatic [...] Read more.

Spaceborne Global Navigation Satellite System Reflectometry (GNSS-R) archives usually provide only one delay–Doppler map (DDM) for each recorded observation condition, limiting the representation of residual DDM variability. This study proposes a Position-Guided Conditional Normalizing Flow (PGCFlow) for observation-grounded probabilistic expansion of ocean bistatic radar cross section (BRCS) DDMs. PGCFlow uses four invertible affine coupling blocks to map a 17 × 11 DDM to an equal-dimensional Gaussian latent space. Wind–Auxiliary Condition Modulation incorporates a seven-dimensional condition vector into affine-parameter prediction, while Position-Guided Cross-Partition Aggregation (PGCA) uses deterministic grid descriptors to retain explicit cell locations and facilitate spatial-dependence modeling. Experiments used 5,819,042 quality-controlled CYGNSS observations from 2024. PGCFlow was compared with a conditional variational autoencoder and a generic conditional invertible neural network on 8000 held-out recorded conditions drawn from the same empirical observation domain, with 16 generated DDMs per condition. Although the cVAE achieved the highest balanced-aggregate structural similarity (SSIM) of 0.9396, PGCFlow obtained the lowest Fair Energy Score (FES) and Variogram Score (VS) of 0.2242 and 0.0641 and the closest relative local-neighborhood dispersion to unity at 1.0501. It also achieved the lowest frozen-estimator response RMSE and response MAE of 1.1900 and 0.9129 m/s, respectively. Ablation results indicated individual contributions from both proposed modules. Overall, PGCFlow achieved a favorable trade-off among the evaluated fidelity, dependence, dispersion, and response-consistency measures. Full article

(This article belongs to the Section Physical Oceanography)

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28 pages, 10633 KB

Open AccessArticle

A Deep-Learning Surrogate Model for Predicting the Broadband Radiated Sound Power of Submerged Cylindrical Shells

by Ramazan Tufan Azrak, Bülent Düz, Yordan Garbatov and Bahadır Uğurlu

J. Mar. Sci. Eng. 2026, 14(17), 1649; https://doi.org/10.3390/jmse14171649 - 4 Sep 2026

Abstract

A residual multilayer perceptron (ResNetMLP) surrogate framework is presented to predict the broadband radiated sound power spectra of submerged circular cylindrical shells. The surrogate maps the shell mean radius, wall thickness, and longitudinal excitation position to the unit-force sound power spectra generated by [...] Read more.

A residual multilayer perceptron (ResNetMLP) surrogate framework is presented to predict the broadband radiated sound power spectra of submerged circular cylindrical shells. The surrogate maps the shell mean radius, wall thickness, and longitudinal excitation position to the unit-force sound power spectra generated by a high-fidelity frequency-domain solver. The trained model is deployed within a diagonal power superposition scheme using equivalent nodal forces derived from an unsteady computational fluid dynamics surface pressure field. Comparing surrogate predictions with direct diagonal vibroacoustic calculations confirms the high predictive accuracy within the diagonal approximation. Crucially, a key limitation of sound power-based surrogates is highlighted: because acoustic power is a quadratic scalar quantity, it cannot capture phase-coherent load interaction, providing a clear rationale for future pressure-based surrogate formulations. Full article

(This article belongs to the Special Issue Analysis of Strength, Fatigue, and Vibration in Marine Structures)

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18 pages, 10469 KB

Open AccessArticle

Integrated Seismic–Electromagnetic Data Fusion and Inversion for the Characterization of Gas Hydrate Reservoirs in the Shenhu Sea Area, South China Sea

by Miaomiao Meng, Wei Deng, Kaijun Xu, Zhongliang Wu, Jin Liang and Jianping Li

J. Mar. Sci. Eng. 2026, 14(17), 1648; https://doi.org/10.3390/jmse14171648 - 4 Sep 2026

Abstract

The integrated fusion and inversion of seismic data and marine controlled-source electromagnetic (MCSEM) data can identify the gas hydrate distributions. However, due to differences in observation systems and scales between seismic and MCSEM data, current fusion methods have failed to effectively address the [...] Read more.

The integrated fusion and inversion of seismic data and marine controlled-source electromagnetic (MCSEM) data can identify the gas hydrate distributions. However, due to differences in observation systems and scales between seismic and MCSEM data, current fusion methods have failed to effectively address the critical issue of physical property variation within gas hydrate reservoirs. This research seeks to consolidate the two datasets into a cohesive observational framework. By transforming the MCSEM data into low-frequency constraints applicable to seismic impedance inversion, it is possible to realize an effective integrative interpretation that combines both seismic and MCSEM data. Using a 3 km-long seismic dataset and MCSEM data from the Shenhu Sea area in the South China Sea as a case study, we apply the Poisson blending algorithm to integrate seismic and MCSEM data, enabling precise identification and characterization of gas hydrate reservoirs and underlying gas-bearing fluids. The gas hydrate saturation results, derived from seismic inversion constrained by MCSEM data, demonstrate strong consistency with well logging and geological interpretation. This concordance validates the efficacy of the integrated fusion and inversion methodology and highlights its advantages in accurately predicting the spatial distribution of gas hydrate enrichment. The developmental positions of deep gas-bearing fluid pathways, coupled with the fault locations within the free gas zone and gas hydrate-bearing layer, play significant roles in the heterogeneous enrichment of gas hydrates. This research provides important technical and theoretical support for the precise and efficient prediction of gas hydrate reservoirs. Full article

(This article belongs to the Special Issue Advanced Studies of Hydrate-Bearing Marine Sediments)

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38 pages, 11886 KB

Open AccessArticle

Hydrodynamic Performance and Bucket-Controlled Turning Optimization of an Amphibious Rescue and Operation Platform with Detachable Floating Boxes

by Junjie Li, Bolong Liu, Xiaojun Xu and Yaxin Xie

J. Mar. Sci. Eng. 2026, 14(17), 1647; https://doi.org/10.3390/jmse14171647 - 4 Sep 2026

Abstract

This study investigates the hydrodynamic behavior of an amphibious rescue and operation platform equipped with detachable floating boxes and a front bucket system, and it further develops a control-oriented turning optimization framework for a two-bucket steering configuration. Calm-water resistance, free-surface evolution, running attitude, [...] Read more.

This study investigates the hydrodynamic behavior of an amphibious rescue and operation platform equipped with detachable floating boxes and a front bucket system, and it further develops a control-oriented turning optimization framework for a two-bucket steering configuration. Calm-water resistance, free-surface evolution, running attitude, and roll decay were analyzed using a Reynolds-averaged Navier–Stokes/volume-of-fluid solver with overset grids and dynamic fluid–body interaction. Straight-ahead non-rotating cases were computed using a symmetry-based half-domain model, whereas roll- and turning-related cases were simulated in the full domain. The numerical method was validated against towing-tank data for a benchmark amphibious vehicle, and the predicted resistance showed an overall deviation of 2.11%. The results show that the detachable floating boxes slightly increase resistance at 2 km/h, but reduce resistance by approximately 11.4% at 8 km/h owing to favorable wave interference. They also reduce trim and heave over the investigated speed range and markedly improve transverse stability, with the roll motion decaying to nearly zero within about 20 s. By contrast, the installation of the bucket substantially increases hydrodynamic resistance; at the design cruising speed of 8 km/h, the resistance increase reaches about 74.4%, while a bucket-induced bow-down moment modifies the running attitude and suppresses heave. At cruising speed, the bucket swing-arm angle has a non-monotonic influence: the resistance reaches a local peak near 6°, the minimum resistance is obtained at 20°, and the smallest trim is achieved at 4°. Based on these findings, a symmetry-preserving hydrodynamic surrogate and a constrained optimization strategy were established for bucket-controlled turning-radius allocation. The results indicate that differential bucket motion is the primary steering mechanism, whereas the bucket-arm angle provides secondary steering amplification at the cost of additional drag. The present study provides an integrated hydrodynamic basis for the design, operation, and steering-oriented control allocation of amphibious rescue platforms. Full article

(This article belongs to the Section Ocean Engineering)

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27 pages, 2302 KB

Open AccessArticle

Route-Integrity Constraints for Inland-Vessel Speed Planning: Detecting and Limiting Segment-Level Burden Transfer

by Chenyu Wang, Jiaqi Xu and Xiangwei Liu

J. Mar. Sci. Eng. 2026, 14(17), 1646; https://doi.org/10.3390/jmse14171646 - 4 Sep 2026

Abstract

Inland-vessel speed reductions targeted at priority segments can reallocate a normalized burden proxy across a fixed corridor. We develop a route-integrity speed-planning model that accepts a plan only when it attains the priority target, preserves route-wide improvement, and caps the largest non-priority-segment increase. [...] Read more.

Inland-vessel speed reductions targeted at priority segments can reallocate a normalized burden proxy across a fixed corridor. We develop a route-integrity speed-planning model that accepts a plan only when it attains the priority target, preserves route-wide improvement, and caps the largest non-priority-segment increase. The kinematics distinguish speed over ground, along-route current, and speed through water; without voyage-matched current or speed-through-water observations, the cases use zero-current analytical references. We evaluate two AIS-derived cases: the 27-point Case A as a sparse stress test and Case B as the primary spatial case after WGS84 and ESA WorldCover alignment checks. Under the equal-time constraint, an unprotected 2% target induces local deterioration. With a 0.5% non-priority cap, Case B supports a certified maximum target of 0.999%; a 2% late-arrival allowance raises the certified maximum target to 11.912%. Direct search over 0.1-kn commands finds a feasible plan for Case B; however, none of 1000 sampled ±0.2-kn execution-error profiles remains feasible. The framework identifies model-internal proxy transfer rather than measured energy, emissions, or exposure effects. Full article

(This article belongs to the Section Ocean Engineering)

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24 pages, 14223 KB

Open AccessArticle

Hydrodynamic Modelling and Passive-Particle Transport in the Zadar Channel (Eastern Adriatic)

by Iva Mrša, Diana Mance, Davor Mance and Zoran Mrša

J. Mar. Sci. Eng. 2026, 14(17), 1645; https://doi.org/10.3390/jmse14171645 - 4 Sep 2026

Abstract

This study develops a SCHISM-based hydrodynamic model and an offline Lagrangian virtual-particle workflow for the Zadar Channel, a geometrically complex island–mainland passage in the eastern Adriatic. Independent hourly observations from the MP Zadar tide gauge operated by the Hydrographic Institute of the Republic [...] Read more.

This study develops a SCHISM-based hydrodynamic model and an offline Lagrangian virtual-particle workflow for the Zadar Channel, a geometrically complex island–mainland passage in the eastern Adriatic. Independent hourly observations from the MP Zadar tide gauge operated by the Hydrographic Institute of the Republic of Croatia (HHI) were used to evaluate the modelled free-surface response. After exclusion of the first 24 h ramping period, 192 matched hourly pairs gave a Pearson correlation of 0.913, a mean bias of 0.012 m, a mean absolute error of 0.051 m, and a root-mean-square error of 0.070 m; cross-correlation was maximized at zero lag. The model reproduced the timing of the observed oscillations but underestimated their amplitude, with simulated and observed standard deviations of 0.117 and 0.157 m, respectively. The adopted unstructured mesh contains 16,962 triangular elements and 9081 nodes. In four 24 h particle-sensitivity tests, maximum reach ranges from 8.4 to 14.2 km; a 15-fold change in horizontal diffusivity affects reach less than sampling a lower model layer, which reduces reach by 32.8%. In the June 2025 event calculation, cumulative numerical shoreline contact increases from zero to all 1000 particles. The approximately 4 km Copernicus regional product masks the narrow interior passages and is therefore used only to assess spatial representativeness, not to validate channel currents. The tide-gauge comparison supports the modelled sea-level response and its timing at one station, but does not constitute direct validation of local current velocities. The reported trajectories are current-driven passive-particle diagnostics; wave–current coupling, Stokes drift, and material-specific fate processes are not represented. Full article

(This article belongs to the Section Physical Oceanography)

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27 pages, 7807 KB

Open AccessArticle

Joint Optimization of Energy Replenishment and Sailing Speed for Inland Electric Vessels Under Time-of-Use Pricing

by Siqing Guo, Yubing Wang, Mingyuan Yue, Lei Dai, Hao Hu, Shaosong Zhu and Yuni Li

J. Mar. Sci. Eng. 2026, 14(17), 1644; https://doi.org/10.3390/jmse14171644 - 4 Sep 2026

Abstract

Battery-powered propulsion offers a pathway for reducing inland shipping emissions. However, low battery energy density limits sailing range and may require energy replenishment during a voyage, thereby complicating energy and voyage planning for inland electric vessels. Time-of-use (TOU) pricing creates cost-saving opportunities but [...] Read more.

Battery-powered propulsion offers a pathway for reducing inland shipping emissions. However, low battery energy density limits sailing range and may require energy replenishment during a voyage, thereby complicating energy and voyage planning for inland electric vessels. Time-of-use (TOU) pricing creates cost-saving opportunities but further complicates planning because energy replenishment and sailing speed are closely coupled. This study develops a joint optimization framework for an inland electric vessel under TOU pricing that determines replenishment ports, technologies, amounts, and leg-specific sailing speeds to minimize total replenishment costs. The problem is formulated as a mixed-integer nonlinear programming model and reformulated as a mixed-integer linear programming approximation through equivalent linearization and speed discretization. A Yangtze River case study with five operating conditions evaluates the proposed framework. The results show that, under the proposed framework, TOU pricing reduces total replenishment costs by 42.4–43.4% compared to fixed pricing. Relative to a sailing-speed optimization benchmark, joint optimization under TOU pricing reduces replenishment costs by 9.8–12.5% and energy consumption by 4.2–5.6%. The cost-saving potential also varies with the voyage time limit, voyage start time, relative charging and battery swapping rates, and the availability of opportunity charging. Full article

(This article belongs to the Special Issue Maritime Logistics: Shipping and Port Management)

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22 pages, 18667 KB

Open AccessArticle

Field Environmental Variation and Physiological Responses of Apostichopus japonicus to Major Winter Stressors: Implications for Overwintering Risk Management

by Nan Li, Jinhao Wu, Chaokui Hu, Guangjun Song, Zhaohui Wang, Yutong Liu, Lun Song and Kun Wang

J. Mar. Sci. Eng. 2026, 14(17), 1643; https://doi.org/10.3390/jmse14171643 - 4 Sep 2026

Abstract

Winter ice-cover periods pose substantial risks to Apostichopus japonicus aquaculture in northern China. We combined field monitoring of three representative aquaculture ponds between 2014 and 2017 with controlled single-factor laboratory exposures to low temperature, hypoxia, and hyposalinity in adult and juvenile sea cucumbers. [...] Read more.

Winter ice-cover periods pose substantial risks to Apostichopus japonicus aquaculture in northern China. We combined field monitoring of three representative aquaculture ponds between 2014 and 2017 with controlled single-factor laboratory exposures to low temperature, hypoxia, and hyposalinity in adult and juvenile sea cucumbers. Field observations revealed pronounced temporal, vertical, spatial, and interannual variability in water temperature, salinity, and dissolved oxygen (DO) during freezing and ice-melting periods. All three stressors caused clear deterioration in physiological condition, with juveniles generally exhibiting greater short-term sensitivity than adults under low-temperature and hypoxic exposure, whereas severe hyposalinity caused pronounced deterioration in both life stages. Lactate, malondialdehyde (MDA), and glutathione (GSH) showed distinct treatment- and time-dependent responses, consistent with stress-associated changes in anaerobic metabolism, lipid peroxidation, and glutathione-associated antioxidant status. Integration of field observations with laboratory responses indicated that water temperatures approaching 0 °C and salinities approaching approximately 20‰ represent environmentally relevant conditions associated with elevated overwintering risk. DO concentrations approaching approximately 3 mg/L may warrant intensified monitoring and management intervention, whereas 2 mg/L represents a more severe experimental hypoxia condition. The more extreme treatments of −2 °C and 15‰ should similarly be regarded as severe experimental scenarios rather than commonly occurring field conditions. These environmental values should therefore be interpreted as preliminary management-oriented risk references rather than definitive physiological thresholds. Overall, the study provides an empirical field-to-laboratory basis for biologically informed winter environmental monitoring and risk-based overwintering management of A. japonicus aquaculture. Full article

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26 pages, 13250 KB

Open AccessArticle

An EMD-Based Power Allocation Approach for Hybrid Energy Storage Systems to Smooth PMLG Output Power

by Zhengyuan Zhu, Yuda Sheng, Minshuo Chen, Lei Huang, Wei Qin, Jianlong Yang and Ruisi Guo

J. Mar. Sci. Eng. 2026, 14(17), 1642; https://doi.org/10.3390/jmse14171642 - 4 Sep 2026

Abstract

Direct-drive wave power generation systems based on permanent magnet linear generators (PMLGs) produce fluctuating electromagnetic power under irregular wave excitation, which may affect DC-bus voltage stability and load-side power quality. To smooth the fluctuating output power, this paper develops an empirical mode decomposition [...] Read more.

Direct-drive wave power generation systems based on permanent magnet linear generators (PMLGs) produce fluctuating electromagnetic power under irregular wave excitation, which may affect DC-bus voltage stability and load-side power quality. To smooth the fluctuating output power, this paper develops an empirical mode decomposition (EMD)-based power allocation strategy for a battery–supercapacitor hybrid energy storage system (HESS). In the proposed strategy, EMD is used to decompose the fluctuating electromagnetic power into low-frequency and high-frequency components according to their time-scale characteristics. The low-frequency component is assigned to the battery for energy buffering, while the high-frequency component is assigned to the supercapacitor for transient power compensation. Finite-control-set model predictive current control (FCS-MPCC) is adopted on the generator side to improve the current response of the PMLG, and an MPC-based HESS controller is designed to track the assigned power commands and regulate the DC-bus voltage. Simulation results show a battery power-tracking error of 3.93 W and a DC-bus voltage standard deviation of 0.108 V; compared with LPF, EMD reduced the load-step voltage deviation by 11.94%. Experiments confirm that the PMLG back-EMF follows the translator velocity, the storage currents track their references, and the DC-bus voltage remains within ±2 V of its reference. Full article

(This article belongs to the Special Issue Control and Optimization of Marine Renewable Energy Systems)

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21 pages, 29289 KB

Open AccessArticle

Numerical Simulation Study on the Noise Reduction Mechanism of Biomimetic Microstructure Propellers

by Xinge Geng, Weiguo Wu and Yongshui Lin

J. Mar. Sci. Eng. 2026, 14(17), 1641; https://doi.org/10.3390/jmse14171641 - 3 Sep 2026

Abstract

This study investigates the influence mechanism of biomimetic microstructures on propeller pressure fluctuations and radiated noise using numerical simulations. Based on the SST k-ω turbulence model and Lighthill’s acoustic analogy, the flow field and acoustic performance of propellers with and without [...] Read more.

This study investigates the influence mechanism of biomimetic microstructures on propeller pressure fluctuations and radiated noise using numerical simulations. Based on the SST k-ω turbulence model and Lighthill’s acoustic analogy, the flow field and acoustic performance of propellers with and without microstructures are comparatively analyzed under different advance coefficients. Results show that microstructures arranged at the trailing edge optimize surface pressure distribution and promote a more uniform flow field. More importantly, they facilitate orderly vortex generation and shedding, reducing blade surface vortex intensity and suppressing flow-induced pressure fluctuations at the source. Acoustic analysis confirms that microstructures effectively reduce discrete noise at characteristic frequencies, with far-field maximum sound pressure level reductions of 5.94 dB at J = 0.5 and 3.11 dB at J = 1, while the noise directivity pattern is transformed from a “figure-of-eight” to a “heart-shaped” distribution. This study reveals the hydrodynamic mechanism of passive flow control for noise reduction via biomimetic microstructures, providing novel insights and theoretical foundations for low-noise propeller design and acoustic stealth technology development. Full article

(This article belongs to the Section Ocean Engineering)

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18 pages, 4853 KB

Open AccessArticle

RACIF-SLAM: Reliability-Aware Conflict-Gated LiDAR and W-Band Radar Fusion for Continuous Near-Coastal Localization and Hierarchical Occupancy Mapping

by Zhiyuan Zeng, Jie Wen, Chunxu Li, Yue Zheng and Xiongfei Geng

J. Mar. Sci. Eng. 2026, 14(17), 1640; https://doi.org/10.3390/jmse14171640 - 3 Sep 2026

Abstract

Reliable near-coastal localization is difficult because LiDAR and scanning radar fail in complementary regimes: LiDAR provides precise local geometry but loses support over open water, whereas radar preserves long-range observations but suffers from clutter, multipath, and low spatial resolution. We present RACIF-SLAM, a [...] Read more.

Reliable near-coastal localization is difficult because LiDAR and scanning radar fail in complementary regimes: LiDAR provides precise local geometry but loses support over open water, whereas radar preserves long-range observations but suffers from clutter, multipath, and low spatial resolution. We present RACIF-SLAM, a reliability-aware framework that unifies continuous localization and hierarchical occupancy mapping. RACIF-SLAM transforms sensor-native motion increments into a common vessel frame, infers temporally filtered reliability from registration evidence, and applies an innovation gate to suppress the less credible modality under cross-sensor conflict before fusion on

SE (2)

. When LiDAR tracking collapses, a radar bridge sustains motion estimation and re-anchors the recovered LiDAR segment without trajectory discontinuity. For mapping, LiDAR retains local occupied/free-space authority, while spatially broadened radar evidence extends support beyond the effective LiDAR range. In the four evaluated near-coastal segments, every reported pose was supported by at least one accepted sensor increment; the dead-reckoning fallback was not invoked. Against synchronized dual-antenna GNSS, RACIF-SLAM achieves a mean ATE of 0.700 m and a 10-frame translational RPE of 0.183 m, reductions of 66.3% and 65.1%, respectively, over the next-best evaluated method. These segment-specific results indicate that evidence-dependent authority transfer can improve localization continuity while retaining fine local map structure. Full article

(This article belongs to the Section Ocean Engineering)

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Journal of Marine Science and Engineering

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