Journal of Marine Science and Engineering

24 pages, 4564 KB

Open AccessArticle

Research on Bearing Fault Diagnosis Method of the FPSO Soft Yoke Mooring System Based on Minimum Entropy Deconvolution

by Yanlin Wang, Jiaxi Zhang, Shanshan Sun, Zheliang Fan, Dayong Zhang, Ziguang Jia, Peng Zhang and Yi Huang

J. Mar. Sci. Eng. 2026, 14(2), 235; https://doi.org/10.3390/jmse14020235 - 22 Jan 2026

Viewed by 179

Abstract

The Soft Yoke Mooring (SYM) system is a critical single-point mooring method for Floating Production Storage and Offloading systems (FPSOs) in shallow waters. Its articulated thrust roller bearing operates long-term in harsh marine environments, making it prone to failure and difficult to diagnose. [...] Read more.

The Soft Yoke Mooring (SYM) system is a critical single-point mooring method for Floating Production Storage and Offloading systems (FPSOs) in shallow waters. Its articulated thrust roller bearing operates long-term in harsh marine environments, making it prone to failure and difficult to diagnose. To address the issues of non-stationary signals and fault features submerged in strong noise caused by the bearing’s non-rotational oscillatory motion, this paper proposes an adaptive improved diagnosis scheme based on Minimum Entropy Deconvolution (MED). By optimizing Finite Impulse Response (FIR) filter parameters to adapt to the oscillatory operating conditions and combining joint analysis of time-domain indicators and envelope spectra, precise identification of bearing faults is achieved. Research shows that this method effectively enhances fault impact components. After MED processing, the kurtosis value of the fault signal can be significantly increased from approximately 2.6 to over 8.6. Its effectiveness in noisy environments was verified through simulation. Experiments conducted on a 1:10 scale soft yoke model demonstrated that the MED denoising and filtering signal analysis method can effectively identify damage in the thrust roller bearing of the SYM system under marine conditions characterized by high noise and complex frequencies. This study provides an efficient and reliable method for fault diagnosis of non-rotational oscillatory bearings in complex marine environments, holding significant engineering application value. Full article

(This article belongs to the Special Issue Monitoring and Evaluation of Marine Engineering Equipment and Structures—2nd Edition)

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20 pages, 3644 KB

Open AccessArticle

Influence of CFD Modelling Parameters on Air Injection Behaviour in Ship Air Lubrication Systems

by Gyeongseo Min, Haechan Yun, Younguk Do, Kangmin Kim, Keounghyun Jung, Saishuai Dai, Mehmet Atlar, Daejeong Kim, Seungnam Kim, Sanghyun Kim and Soonseok Song

J. Mar. Sci. Eng. 2026, 14(2), 234; https://doi.org/10.3390/jmse14020234 - 22 Jan 2026

Viewed by 219

Abstract

In response to the International Maritime Organization’s strengthened regulations on carbon emissions, the introduction of novel eco-friendly technologies for ship operators has become necessary. In this context, various energy saving devices such as wind-assisted propulsion systems (e.g., wing/rotor sails), propeller-rudder efficiency enhancers (e.g., [...] Read more.

In response to the International Maritime Organization’s strengthened regulations on carbon emissions, the introduction of novel eco-friendly technologies for ship operators has become necessary. In this context, various energy saving devices such as wind-assisted propulsion systems (e.g., wing/rotor sails), propeller-rudder efficiency enhancers (e.g., pre-swirl stators or ducted propellers), and the gate rudder system have been proposed. Among various energy-saving technologies, the air lubrication system has been widely investigated as an effective means of reducing hull frictional resistance through air injection beneath the hull. The performance of air lubrication systems can be evaluated through experimental testing or computational fluid dynamics (CFD) simulations. However, accurately simulating air lubrication systems in CFD remains challenging. Therefore, this study aims to quantitatively evaluate the influence of numerical parameters on the CFD implementation of air lubrication systems. To evaluate these influences, CFD simulations employing the unsteady Reynolds-averaged Navier–Stokes (URANS) method were conducted to investigate air layer formation and sweep angle on a flat plate. The numerical predictions were systematically compared with experimental results by varying key numerical parameters. These quantitative estimations of the effects of numerical variables are expected to serve as a useful benchmark for CFD simulations of air lubrication systems. Full article

(This article belongs to the Special Issue Advanced Studies in Ship Fluid Mechanics)

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20 pages, 2241 KB

Open AccessArticle

InterSeA: An Unmanned Surface Vehicle (USV) for Monitoring the Marine Surface Microlayer (SML) in Coastal Areas

by Nikolaos Katsikatsos, Aikaterini Sakellari, Theodora Paramana, Georgios Katsouras, Konstantinos Koukoulakis, Evangelos Bakeas, Nikolaos Mavromatis, Theodoros Xenakis, Angeliki Ntourntoureka and Sotirios Karavoltsos

J. Mar. Sci. Eng. 2026, 14(2), 233; https://doi.org/10.3390/jmse14020233 - 22 Jan 2026

Viewed by 183

Abstract

The sea surface microlayer (SML) is a critical biogeochemical boundary, playing a key role in air–sea exchange processes, yet its sampling remains challenging due to potential dilution from subsurface water layers, susceptibility to contamination and labor- and time-consuming procedures. The design, development and [...] Read more.

The sea surface microlayer (SML) is a critical biogeochemical boundary, playing a key role in air–sea exchange processes, yet its sampling remains challenging due to potential dilution from subsurface water layers, susceptibility to contamination and labor- and time-consuming procedures. The design, development and operational verification of a research unmanned surface vehicle (USV), equipped with samplers for collecting both sea surface microlayer and subsurface water samples (SSW), are described in this study. The InterSeA autonomous vessel is of the catamaran type, equipped with an SML sampler consisting of rotating glass discs and a peristaltic pump for collecting SSW samples. Verification analysis with traditional manual sampling techniques (glass plate and mesh screen) revealed that the InterSeA achieved comparable results in terms of reproducibility and contamination control for both the inorganic and organic analytes examined. The results obtained highlight the effectiveness of autonomous platforms in achieving reliable, low-contamination SML sampling, emphasizing their suitability for broader use in marine biogeochemical research demanding high resolution and minimally disturbed interface measurements. InterSeA is one of the smallest and lightest USVs using rotating glass discs for SML sampling. Full article

(This article belongs to the Special Issue Assessment and Monitoring of Coastal Water Quality)

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17 pages, 11315 KB

Open AccessArticle

Dispersion Features of Scholte-like Waves in Ice over Shallow Water: Modeling, Analysis, and Application

by Dingyi Ma, Yuxiang Zhang, Chao Sun, Rui Yang and Xiaoying Liu

J. Mar. Sci. Eng. 2026, 14(2), 232; https://doi.org/10.3390/jmse14020232 - 22 Jan 2026

Viewed by 116

Abstract

Acoustic propagation in the ice cover of the Polar Ocean is of increasing interest from both scientific and engineering perspectives. The low-frequency elastic waves propagating in floating ice are primarily governed by waveguides stemming from the layered structure of the medium. For shallow [...] Read more.

Acoustic propagation in the ice cover of the Polar Ocean is of increasing interest from both scientific and engineering perspectives. The low-frequency elastic waves propagating in floating ice are primarily governed by waveguides stemming from the layered structure of the medium. For shallow water areas, experimental observation indicates that two Scholte-like waves are observed at low frequencies, i.e., the quasi-Scholte (QS) and Scholte–Stoneley (SS) waves, which are different from deep-sea cases. Due to the finite depths of ice, water, and sediment layers, both waves are dispersive. By modeling the waveguide of an ice-covered shallow-water (ICSW) system, the dispersion characteristics of both waves are derived, validated through numerical simulation, and analyzed with respect to layer structure for both soft and hard sediment. Results indicate a consistent conclusion; the QS wave exhibits a unique sensitivity to ice thickness, whereas the SS wave shows marginal sensitivity to ice thickness, and is controlled by the ratio of water depth to sediment depth, regardless of their absolute values. Based on these dispersion characteristics, a two-step inversion procedure is developed and applied to the synthetic signals from a numerical simulation. The conditional observability of the SS wave at the ice surface is also investigated and discussed. Full article

(This article belongs to the Special Issue The Changing Arctic: Ocean–Ice Interactions and Emerging Observational Frontiers)

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26 pages, 4955 KB

Open AccessArticle

Low-Complexity Channel Estimation for Electromagnetic Wave Propagation Across the Seawater-Air Interface: A FRLS Approach

by Honglei Wang, Yulong Wei, Jinbo Song, Yingda Ren and Lichao Ding

J. Mar. Sci. Eng. 2026, 14(2), 231; https://doi.org/10.3390/jmse14020231 - 22 Jan 2026

Viewed by 140

Abstract

This paper proposes a complex fast recursive least-squares (FRLS) channel-estimation algorithm for single-carrier electromagnetic (EM) communications across the seawater–air interface, where severe attenuation and multipath cause strong SNR fluctuations. By redesigning the input-data structure and using forward–backward joint estimation, FRLS reduces the per-iteration [...] Read more.

This paper proposes a complex fast recursive least-squares (FRLS) channel-estimation algorithm for single-carrier electromagnetic (EM) communications across the seawater–air interface, where severe attenuation and multipath cause strong SNR fluctuations. By redesigning the input-data structure and using forward–backward joint estimation, FRLS reduces the per-iteration complexity from the quadratic cost of classical RLS to a linear form (14L + 20 operations per iteration, where L is the channel length). Simulations under representative one- to three-path channels show that FRLS achieves the lowest steady-state mean-square deviation (MSD) at low SNR, outperforming LMS, IPNLMS, RLS, and PRLS. Offshore experiments further validate the practicality: after MMSE equalization, FRLS yields higher OSNR and improves the BER distribution, demonstrating an effective accuracy–complexity trade-off for hardware-constrained cross-medium EM links. Full article

(This article belongs to the Section Ocean Engineering)

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30 pages, 4255 KB

Open AccessArticle

Logistics–Energy Coordinated Scheduling in Hybrid AC/DC Ship–Shore Interconnection Architecture with Enabling Peak-Shaving of Quay Crane Clusters

by Fanglin Chen, Xujing Tang, Hang Yu, Chengqing Yuan, Tian Wang, Xiao Wang, Shanshan Shang and Songbin Wu

J. Mar. Sci. Eng. 2026, 14(2), 230; https://doi.org/10.3390/jmse14020230 - 22 Jan 2026

Viewed by 130

Abstract

With the gradual rise of battery-powered ships, the high-power charging demand during berthing is poised to exacerbate the peak-to-valley difference in the port grid, possibly leading to grid congestion and logistical disruption. To address this challenge, this paper proposes a bi-level coordinated scheduling [...] Read more.

With the gradual rise of battery-powered ships, the high-power charging demand during berthing is poised to exacerbate the peak-to-valley difference in the port grid, possibly leading to grid congestion and logistical disruption. To address this challenge, this paper proposes a bi-level coordinated scheduling scheme across both logistical operations and energy flow dispatch. Initially, by developing a refined model for the dynamic power characteristics of quay crane (QC) clusters, the surplus power capacity that can be stably released through an orderly QC operational delay is quantified. Subsequently, a hybrid AC/DC ship–shore interconnection architecture based on a smart interlinking unit (SIU) is proposed to utilize the QC peak-shaving capacity and satisfy the increasing shore power demand. In light of these, at the logistics level a coordinated scheduling of berths, QCs, and ships charging is performed with the objective of minimizing port berthing operational costs. At the energy flow level, the coordinated delay in QC clusters’ operations and SIU-enabled power dispatching are implemented for charging power support. The case studies demonstrate that, compared with the conventional independent operational mode, the proposed coordinated scheduling scheme enhances the shore power supply capability by utilizing the QC peak-shaving capability effectively. Moreover, as well as satisfying the charging demands of electric ships, the proposed scheme significantly reduces the turnaround time of ships and achieves a 39.29% reduction in port berthing operational costs. Full article

(This article belongs to the Topic Advancing Sustainable Water Transportation: Integration of Renewable Energy and Energy Efficiency Optimization)

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20 pages, 13461 KB

Open AccessArticle

Multi-View 3D Reconstruction of Ship Hull via Multi-Scale Weighted Neural Radiation Field

by Han Chen, Xuanhe Chu, Ming Li, Yancheng Liu, Jingchun Zhou, Xianping Fu, Siyuan Liu and Fei Yu

J. Mar. Sci. Eng. 2026, 14(2), 229; https://doi.org/10.3390/jmse14020229 - 21 Jan 2026

Viewed by 184

Abstract

The 3D reconstruction of vessel hulls is crucial for enhancing safety, efficiency, and knowledge in the maritime industry. Neural Radiance Fields (NeRFs) are an alternative to 3D reconstruction and rendering from multi-view images; particularly, tensor-based methods have proven effective in improving efficiency. However, [...] Read more.

The 3D reconstruction of vessel hulls is crucial for enhancing safety, efficiency, and knowledge in the maritime industry. Neural Radiance Fields (NeRFs) are an alternative to 3D reconstruction and rendering from multi-view images; particularly, tensor-based methods have proven effective in improving efficiency. However, existing tensor-based methods typically suffer from a lack of spatial coherence, resulting in gaps in the reconstruction of fine-grained geometric structures. This paper proposes a spatial multi-scale weighted NeRF (MDW-NeRF) for accurate and efficient surface reconstruction of vessel hulls. The proposed method develops a novel multi-scale feature decomposition mechanism that models 3D space by leveraging multi-resolution features, facilitating the integration of high-resolution details with low-resolution regional information. We designed separate color and density weighting, using a coarse-to-fine strategy, for density and a weighted matrix for color to decouple feature vectors from appearance attributes. To boost the efficiency of 3D reconstruction and rendering, we implement a hybrid sampling point strategy for volume rendering, selecting sample points based on volumetric density. Extensive experiments on the SVH dataset confirm MDW-NeRF’s superiority: quantitatively, it outperforms TensoRF by 1.5 dB in PSNR and 6.1% in CD, and shrinks the model size by 9%, with comparable training times; qualitatively, it resolves tensor-based methods’ inherent spatial incoherence and fine-grained gaps, enabling accurate restoration of hull cavities and realistic surface texture rendering. These results validate our method’s effectiveness in achieving excellent rendering quality, high reconstruction accuracy, and timeliness. Full article

(This article belongs to the Special Issue Theories and Techniques in Intelligent Digital Twins in Marine Science and Engineering)

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18 pages, 3332 KB

Open AccessArticle

Experimental Investigation of the Performance of an Artificial Backfill Rock Layer Against Anchor Impacts for Submarine Pipelines

by Yang He, Chunhong Hu, Kunming Ma, Guixi Jiang, Yunrui Han and Long Yu

J. Mar. Sci. Eng. 2026, 14(2), 228; https://doi.org/10.3390/jmse14020228 - 21 Jan 2026

Viewed by 185

Abstract

Subsea pipelines are critical lifelines for marine resource development, yet they face severe threats from accidental ship anchor impacts. This study addresses the scientific challenge of quantifying the “protection margin” of artificial rock-dumping layers, moving beyond traditional passive structural response to a “Critical [...] Read more.

Subsea pipelines are critical lifelines for marine resource development, yet they face severe threats from accidental ship anchor impacts. This study addresses the scientific challenge of quantifying the “protection margin” of artificial rock-dumping layers, moving beyond traditional passive structural response to a “Critical Failure Intervention” logic. Based on the energy criteria of DNV-RP-F107, a critical velocity required to trigger Concrete Weight Coating (CWC) failure for a bare pipe was derived and established as the Safety Factor baseline (S = 1). Two groups of scaled model tests (1:15) were conducted using a Hall anchor to simulate impact scenarios, where impact forces were measured via force sensors beneath the pipeline under varying backfill thicknesses and configurations. Results show that artificial backfill provides a significant protective redundancy; a 10 cm coarse rock layer increases the safety factor to 3.69 relative to the H₀ baseline, while a multi-layer configuration (sand bedding plus coarse rock) elevates S to 27. Analysis reveals a non-linear relationship between backfill thickness and cushioning efficiency, characterized by diminishing marginal utility once a specific thickness threshold is reached. These findings indicate that while thickness is critical for extreme impacts, the protection efficiency optimizes at specific depths, providing a quantifiable framework to reduce small-particle layers in engineering projects without compromising safety. Full article

(This article belongs to the Special Issue Advances in Marine Geotechnical Engineering and Disaster Prevention Engineering)

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23 pages, 2429 KB

Open AccessArticle

Development and Field Testing of a Cavitation-Based Robotic Platform for Sustainable In-Water Hull Cleaning

by Uroš Puc, Andreja Abina, Edvin Salvi, Vlado Malačič, Janja Francé, Riccardo Zanelli and Aleksander Zidanšek

J. Mar. Sci. Eng. 2026, 14(2), 227; https://doi.org/10.3390/jmse14020227 - 21 Jan 2026

Viewed by 225

Abstract

Biofouling on ship hulls significantly increases hydrodynamic drag, fuel consumption, and greenhouse gas emissions, while also facilitating the spread of invasive species in regional and global waters, thereby threatening marine biodiversity. To address these environmental and economic issues, we developed an innovative robotic [...] Read more.

Biofouling on ship hulls significantly increases hydrodynamic drag, fuel consumption, and greenhouse gas emissions, while also facilitating the spread of invasive species in regional and global waters, thereby threatening marine biodiversity. To address these environmental and economic issues, we developed an innovative robotic platform for in-water hull cleaning. The platform utilizes a cavitation-based cleaning module that removes biofouling while minimizing hull surface damage and preventing the spread of detached particles into the marine environment. This paper describes the design, operation, and testing of a developed robotic cleaning system prototype. Emphasis is placed on integrating components and sensors for continuous monitoring of key seawater parameters (temperature, salinity, turbidity, dissolved oxygen, chlorophyll-a, etc.) before, during, and after underwater cleaning. Results from real-sea trials show the platform’s effectiveness in removing biofouling and its minimal environmental impact, confirming its potential as a sustainable solution for in-water hull cleaning. Full article

(This article belongs to the Section Ocean Engineering)

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24 pages, 1145 KB

Open AccessReview

Methodological Approaches to Battery-Powered Ro-Pax Ferries in Domestic Shipping: A Systematic Review of Route-Based Case Studies

by Roko Glavinović, Luka Vukić, Veljko Plazibat and Maja Račić

J. Mar. Sci. Eng. 2026, 14(2), 226; https://doi.org/10.3390/jmse14020226 - 21 Jan 2026

Viewed by 208

Abstract

Maritime transport is responsible for 3% of global greenhouse gas (GHG) emissions, making it a focus of decarbonization efforts. Ro-pax ferries, operating in the domestic shipping, are particularly emission-intensive due to their high operational frequency, while advances in battery-powered propulsion suggest that electrification [...] Read more.

Maritime transport is responsible for 3% of global greenhouse gas (GHG) emissions, making it a focus of decarbonization efforts. Ro-pax ferries, operating in the domestic shipping, are particularly emission-intensive due to their high operational frequency, while advances in battery-powered propulsion suggest that electrification is feasible on short to medium distance routes. This paper uses a systematic literature review of studies published between 2014 and 2024 to investigate the application of battery-powered ferries from a maritime transport system perspective. Using the PRISMA 2020 guidelines, the authors identified 15 case-study-based papers on battery-powered ferries, with a specific focus on the methodological approaches applied to domestic shipping routes. The goal of this review is to identify and systematize the methodologies used in case study research to analyze the implementation of battery-powered ferries on specific routes. The review contributes a structured synthesis of (I) methodological approaches, grouped into four clusters, and (II) route framing and selection practices using a three-level route classification, revealing an increasing methodological complexity, from single-route feasibility assessments to diversified, maritime network-integrated approaches. The paper systematically links existing methodologies to operational and conceptual case studies, providing practical insights for future decarbonization projects. Full article

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27 pages, 8648 KB

Open AccessArticle

A Driver’s Bumpy Feeling Reproducing Model Applied to the Six-Degree-of-Freedom Ship Simulation Driving Equipment

by Quanzheng Wang, Xiaoyuan Wang, Jingheng Wang, Tinglin Chen, Han Zhang, Kai Feng, Junlin Li, Yabin Li and Yuhan Jiang

J. Mar. Sci. Eng. 2026, 14(2), 225; https://doi.org/10.3390/jmse14020225 - 21 Jan 2026

Viewed by 124

Abstract

With the continuous development of global intelligent shipping technology, in fields such as virtual testing of intelligent ships and crew training and assessment, there is an urgent need for a highly realistic model to reproduce the driver’s bumpy feeling of ship drivers. Due [...] Read more.

With the continuous development of global intelligent shipping technology, in fields such as virtual testing of intelligent ships and crew training and assessment, there is an urgent need for a highly realistic model to reproduce the driver’s bumpy feeling of ship drivers. Due to the limited travel of the six-degree-of-freedom platform, the platform is unable to provide continuous acceleration during the simulation of the driver’s body sensation in the three degrees of freedom of the ship, namely, sway, surge, and yaw. To overcome the above problems, a six-degree-of-freedom motion model of ships is constructed under low sea conditions based on the MMG-separated ship motion model and the FFT wave simulation method. Secondly, the otolith model and the semicircular canal model are introduced to establish a human body perception deception mechanism. The gravity is transferred by using the deflection angles of roll and pitch to extend the acceleration sensation in the three degrees of freedom of sway, surge, and yaw. Finally, through the real ship rotation and Z-shaped test experiments, the simulation trajectory, real ship attitude, and platform motion data are compared to verify the effectiveness of the established method. To simplify the research, under the low sea conditions where the three degrees of freedom of heave, roll, and pitch are ignored, the virtual ship simulation trajectory based on the above method is basically consistent with the real ship, and the correlation between the platform and the real ship body-sensing data is at least 81.2%. Through scoring the simulation driving body-sensing reproduction experience, it is proven that the above method can achieve a better body-sensing reproduction effect on the six-degree-of-freedom platform. Full article

(This article belongs to the Special Issue Management and Control of Ship Traffic Behaviours)

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21 pages, 5567 KB

Open AccessArticle

Classification of Double-Bottom U-Shaped Weld Joints Using Synthetic Images and Image Splitting

by Gyeonghoon Kang and Namkug Ku

J. Mar. Sci. Eng. 2026, 14(2), 224; https://doi.org/10.3390/jmse14020224 - 21 Jan 2026

Viewed by 135

Abstract

The shipbuilding industry relies heavily on welding, which accounts for approximately 70% of the overall production process. However, the recent decline in skilled workers, together with rising labor costs, has accelerated the automation of shipbuilding operations. In particular, the welding activities are concentrated [...] Read more.

The shipbuilding industry relies heavily on welding, which accounts for approximately 70% of the overall production process. However, the recent decline in skilled workers, together with rising labor costs, has accelerated the automation of shipbuilding operations. In particular, the welding activities are concentrated in the double-bottom region of ships, where collaborative robots are increasingly introduced to alleviate workforce shortages. Because these robots must directly recognize U-shaped weld joints, this study proposes an image-based classification system capable of automatically identifying and classifying such joints. In double-bottom structures, U-shaped weld joints can be categorized into 176 types according to combinations of collar plate type, slot, watertight feature, and girder. To distinguish these types, deep learning-based image recognition is employed. To construct a large-scale training dataset, 3D Computer-Aided Design (CAD) models were automatically generated using Open Cascade and subsequently rendered to produce synthetic images. Furthermore, to improve classification performance, the input images were split into left, right, upper, and lower regions for both training and inference. The class definitions for each region were simplified based on the presence or absence of key features. Consequently, the classification accuracy was significantly improved compared with an approach using non-split images. Full article

(This article belongs to the Section Ocean Engineering)

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28 pages, 6693 KB

Open AccessArticle

Optimization of Collaborative Vessel Scheduling for Offshore Wind Farm Installation Under Weather Uncertainty

by Shengguan Qu, Changmao Yu, Yang Zhou, Yi Hou, Jianhua Wang and Fenglei Li

J. Mar. Sci. Eng. 2026, 14(2), 223; https://doi.org/10.3390/jmse14020223 - 21 Jan 2026

Viewed by 197

Abstract

The construction cost of offshore wind farms (OWFs) is heavily influenced by vessel scheduling and meteorological uncertainties. To address these challenges, this paper proposes a constraint-driven hierarchical optimization framework for the coordinated scheduling of installation vessels (IVs) and transport vessels (TVs). First, a [...] Read more.

The construction cost of offshore wind farms (OWFs) is heavily influenced by vessel scheduling and meteorological uncertainties. To address these challenges, this paper proposes a constraint-driven hierarchical optimization framework for the coordinated scheduling of installation vessels (IVs) and transport vessels (TVs). First, a Mixed-Integer Linear Programming (MILP) model is established to describe the operational constraints, which is then decomposed into two interrelated sub-problems: vessel path planning and scheduling optimization. For path planning, the problem is modeled as a Multiple Traveling Salesman Problem (MTSP) to ensure balanced fleet workloads. This stage is solved via a tailored three-stage heuristic combining balanced sweep clustering and penalized local search. For scheduling optimization, a hybrid Earliest Deadline First (EDF)-Simulated Annealing (SA) strategy is employed, where EDF generates a strictly feasible baseline to warm-start the SA optimization. Furthermore, a stochastic optimization approach integrates historical meteorological data to ensure schedule robustness against weather uncertainty. The validity of the framework is supported by two real-world OWF cases, which demonstrate total cost reductions of 15.44% and 13.20%, respectively, under stochastic weather conditions. These results demonstrate its effectiveness in solving high-constraint offshore engineering problems. Full article

(This article belongs to the Section Ocean Engineering)

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23 pages, 9948 KB

Open AccessArticle

Quantifying the Uncertainties in Projecting Extreme Coastal Hazards: The Overlooked Role of the Radius of Maximum Wind Parameterizations

by Hao Kang, Shengtao Du, Guoxiang Wu, Bingchen Liang, Luming Shi, Xinyu Wang, Bo Yang and Zhenlu Wang

J. Mar. Sci. Eng. 2026, 14(2), 222; https://doi.org/10.3390/jmse14020222 - 21 Jan 2026

Viewed by 149

Abstract

Parametric tropical cyclone models are widely used to generate large wind field ensembles for assessing extreme storm tides and wave heights. The radius of maximum wind (RMW) is a key model parameter and is commonly estimated using empirical formulas. This study shows that [...] Read more.

Parametric tropical cyclone models are widely used to generate large wind field ensembles for assessing extreme storm tides and wave heights. The radius of maximum wind (RMW) is a key model parameter and is commonly estimated using empirical formulas. This study shows that uncertainty introduced by the choice of RMW formulas has been largely overlooked in tropical cyclone risk assessments. Using the Pearl River Estuary as a case study, historical wind fields (1981–2024) were generated with a parametric tropical cyclone model combined with eight empirical RMW formulas. Storm tides and wave heights during tropical cyclone events were simulated using a coupled wave–current model (ROMS–SWAN) and analyzed with extreme value theory. The results indicate that, for estuarine nearshore zones, the 100-year return period of water level and significant wave height vary by up to 1.26 m and 1.54 m, respectively, across all the selected RMW formulas. Joint probability analysis further shows that RMW uncertainty can shift the joint return period of the same compound storm tide and wave event from 100 years to 10 years. For an individual extreme event, differences in the RMW formula alone can produce deviations up to 2.11 m in peak storm tide levels and 3.8 m in significant wave heights. Such differences can also change the duration of extreme sea states by 13 h. These results highlight that RMW formula selection is a critical uncertainty factor, and related uncertainty should be considered in large-sample tropical cyclone hazard assessment and engineering design. Full article

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

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28 pages, 9071 KB

Open AccessArticle

C-HILS-Based Evaluation of Control Performance, Losses, and Thermal Lifetime of a Marine Propulsion Inverter

by Seohee Jang, Hyeongyo Chae and Chan Roh

J. Mar. Sci. Eng. 2026, 14(2), 221; https://doi.org/10.3390/jmse14020221 - 21 Jan 2026

Viewed by 150

Abstract

This paper presents a controller-hardware-in-the-loop simulation (C-HILS) framework for validating models, evaluating control performance, and assessing the thermal lifetime of a tens-of-kilowatt inverter. The real inverter and the C-HILS platform were operated in parallel, and accuracy was quantified using phase-current root mean square [...] Read more.

This paper presents a controller-hardware-in-the-loop simulation (C-HILS) framework for validating models, evaluating control performance, and assessing the thermal lifetime of a tens-of-kilowatt inverter. The real inverter and the C-HILS platform were operated in parallel, and accuracy was quantified using phase-current root mean square error, voltage spectral analysis, and total harmonic distortion (THD). Across a wide range of SVPWM and DPWM cases, deviations remained within 2–5%, confirming close agreement between experiment and simulation. Using the validated C-HILS system, sampling frequency and output power were swept while comparing current tracking, THD, average switching frequency, semiconductor losses, and efficiency. SVPWM achieved lower THD, whereas DPWM reduced average switching frequency and switching losses, improving efficiency. C-HILS waveforms were then applied to a Foster thermal network to reconstruct the junction–temperature trajectory;

T_{j} (t)

, and

Δ T_{j}

and

T_{j, m i n}

were mapped to lifetime using the Bayerer model. For a representative cyclic mission,

Δ T_{j}

decreased from approximately

25.6 ° C

with SVPWM to about

17.5 ° C

with DPWM, increasing the estimated lifetime from approximately 1.36 years to 9.14 years. These results demonstrate that the proposed C-HILS framework provides a unified pre-prototype tool for model verification, control strategy comparison, and quantitative thermal reliability assessment of shipboard propulsion inverters. Full article

(This article belongs to the Special Issue Green Energy with Advanced Propulsion Systems for Net-Zero Shipping)

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21 pages, 4619 KB

Open AccessArticle

Experimental Study on Suppression and Mechanism of Sloshing Impact Pressure by Vertical Slat Screens Under Broadband Horizontal and Vertical Excitation

by Liting Yu, Xiaoqian Luo, Jingcheng Lin, Jie Fan and Heng Jin

J. Mar. Sci. Eng. 2026, 14(2), 220; https://doi.org/10.3390/jmse14020220 - 21 Jan 2026

Viewed by 136

Abstract

Sloshing-induced impact pressure is a key damage factor for marine liquid tanks. While research aimed at overcoming screen failure in sloshing suppression under high-frequency excitation has focused on wave height, the dataset of impact pressure remains lacking. Moreover, the pattern of pressure suppression [...] Read more.

Sloshing-induced impact pressure is a key damage factor for marine liquid tanks. While research aimed at overcoming screen failure in sloshing suppression under high-frequency excitation has focused on wave height, the dataset of impact pressure remains lacking. Moreover, the pattern of pressure suppression under broadband excitation remains unclear. The primary contribution of this work is the first experimental dataset of impact pressure with vertical slat screens under broadband horizontal and vertical excitation. Second, it reveals pressure suppression patterns by screens across varying excitation frequencies and screen numbers. The results demonstrate that vertical slat screens can effectively suppress pressure. First, screen position matters more than number, proving that suppression is dominated by modal disturbance. Second, wave-height suppression does not reliably represent pressure suppression. Pressure suppression is systematically weaker. An exception occurs under vertical excitation, where pressure suppression can be stronger even when wave-height suppression fails. The results highlight the suppression mechanism dominated by modal disturbance and the instability inherent to parametric sloshing. Wave height, reflecting global potential energy, is effectively suppressed by modal disturbance. Pressure, originating from local kinetic energy, can be effectively suppressed by both modal disturbance and vortex dissipation. Full article

(This article belongs to the Special Issue Advances in Marine Engineering Hydrodynamics, 2nd Edition)

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24 pages, 4875 KB

Open AccessArticle

Design of a High-Fidelity Motion Data Generator for Unmanned Underwater Vehicles

by Li Lin, Hongwei Bian, Rongying Wang, Wenxuan Yang and Hui Li

J. Mar. Sci. Eng. 2026, 14(2), 219; https://doi.org/10.3390/jmse14020219 - 21 Jan 2026

Viewed by 133

Abstract

To address the urgent need for high-fidelity motion data for validating navigation algorithms for Unmanned Underwater Vehicles (UUVs), this paper proposes a data generation method based on a parametric motion model. First, based on the principles of rigid body dynamics and fluid mechanics, [...] Read more.

To address the urgent need for high-fidelity motion data for validating navigation algorithms for Unmanned Underwater Vehicles (UUVs), this paper proposes a data generation method based on a parametric motion model. First, based on the principles of rigid body dynamics and fluid mechanics, a decoupled six-degrees-of-freedom (6-DOF) Linear and Angular Acceleration Vector (LAAV) model is constructed, establishing a dynamic mapping relationship between the rudder angle and speed setting commands and motion acceleration. Second, a segmentation–identification framework is proposed for three-dimensional trajectory segmentation, integrating Gaussian Process Regression and Ordering Points To Identify the Clustering Structure (GPR-OPTICS), along with a Dynamic Immune Genetic Algorithm (DIGA). This framework utilizes real vessel data to achieve motion segment clustering and parameter identification, completing the construction of the LAAV model. On this basis, by introducing sensor error models, highly credible Inertial Measurement Unit (IMU) data are generated, and a complete attitude, velocity, and position (AVP) motion sequence is obtained through an inertial navigation solution. Experiments demonstrate that the AVP data generated by our method achieve over 88% reliability compared with the real vessel dataset. Furthermore, the proposed method outperforms the PSINS toolbox in both the reliability and accuracy of all motion parameters. These results validate the effectiveness and superiority of our proposed method, which provides a high-fidelity data benchmark for research on underwater navigation algorithms. Full article

(This article belongs to the Section Ocean Engineering)

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22 pages, 7096 KB

Open AccessArticle

An Improved ORB-KNN-Ratio Test Algorithm for Robust Underwater Image Stitching on Low-Cost Robotic Platforms

by Guanhua Yi, Tianxiang Zhang, Yunfei Chen and Dapeng Yu

J. Mar. Sci. Eng. 2026, 14(2), 218; https://doi.org/10.3390/jmse14020218 - 21 Jan 2026

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Abstract

Underwater optical images often exhibit severe color distortion, weak texture, and uneven illumination due to light absorption and scattering in water. These issues result in unstable feature detection and inaccurate image registration. To address these challenges, this paper proposes an underwater image stitching [...] Read more.

Underwater optical images often exhibit severe color distortion, weak texture, and uneven illumination due to light absorption and scattering in water. These issues result in unstable feature detection and inaccurate image registration. To address these challenges, this paper proposes an underwater image stitching method that integrates ORB (Oriented FAST and Rotated BRIEF) feature extraction with a fixed-ratio constraint matching strategy. First, lightweight color and contrast enhancement techniques are employed to restore color balance and improve local texture visibility. Then, ORB descriptors are extracted and matched via a KNN (K-Nearest Neighbors) nearest-neighbor search, and Lowe’s ratio test is applied to eliminate false matches caused by weak texture similarity. Finally, the geometric transformation between image frames is estimated by incorporating robust optimization, ensuring stable homography computation. Experimental results on real underwater datasets show that the proposed method significantly improves stitching continuity and structural consistency, achieving 40–120% improvements in SSIM (Structural Similarity Index) and PSNR (peak signal-to-noise ratio) over conventional Harris–ORB + KNN, SIFT (scale-invariant feature transform) + BF (brute force), SIFT + KNN, and AKAZE (accelerated KAZE) + BF methods while maintaining processing times within one second. These results indicate that the proposed method is well-suited for real-time underwater environment perception and panoramic mapping on low-cost, micro-sized underwater robotic platforms. Full article

(This article belongs to the Section Ocean Engineering)

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17 pages, 12354 KB

Open AccessArticle

Hybrid Explicit-Implicit FEM for Porous Media Multiphase Flow with Possible Solid-Phase Decomposition

by Qi Zhang and Xiaoran Sheng

J. Mar. Sci. Eng. 2026, 14(2), 217; https://doi.org/10.3390/jmse14020217 - 21 Jan 2026

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Abstract

Multiphase flow in porous media is ubiquitous in physical processes, yet modeling it consistently remains difficult, and sometimes it can be coupled with solid-phase decomposition and phase change, such as in hydrate dissociation or internal erosion processes. Recent code comparison studies have highlighted [...] Read more.

Multiphase flow in porous media is ubiquitous in physical processes, yet modeling it consistently remains difficult, and sometimes it can be coupled with solid-phase decomposition and phase change, such as in hydrate dissociation or internal erosion processes. Recent code comparison studies have highlighted this difficulty, revealing clear inconsistencies in numerical results across different research groups for the same benchmark problem. This paper presents a new, reliable benchmark test and a hybrid explicit-implicit finite element method adaptable to various scenarios. In our mathematical framework, the solid decomposition is described by a rate equation for porosity that depends on the fluid pressure, and the phase change is modeled via mass source terms. The hybrid explicit-implicit finite element method features a novel three-stage updating strategy, which incorporates an artificial diffusion term and carefully selects the transport equation for the final saturation update. Validation results demonstrate that our proposed method achieves substantial agreement with those of the fully implicit finite volume method, confirming its reliability. Furthermore, our analysis confirms that the saturation update must use the transport equation of the incompressible fluid phase, and that the artificial diffusion term is critical for capturing physically correct saturation profiles, even when advection is not dominant. Overall, this work provides a consistent and effective tool for simulating complex multiphase flow scenarios and serves as a valuable complement to future benchmark studies. Full article

(This article belongs to the Special Issue Offshore Geomechanics and Natural Gas Hydrate Exploitation)

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25 pages, 9604 KB

Open AccessArticle

Shaft-Rate Magnetic Field Localization Algorithm Based on Improved Exponential Triangular Optimization

by Bozhong Lei, Ranfeng Wang, Cheng Chi, Lu Yu, Zhentao Yu and Dan Wang

J. Mar. Sci. Eng. 2026, 14(2), 216; https://doi.org/10.3390/jmse14020216 - 20 Jan 2026

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Abstract

Addressing the issues of low positioning accuracy and poor robustness in shaft-rate magnetic fields, this study introduces the Improved Exponential Triangular Optimization Algorithm (IETO). By incorporating adaptive attenuation factors, dynamic population reduction, and intelligent boundary contraction strategies, it significantly enhances the global search [...] Read more.

Addressing the issues of low positioning accuracy and poor robustness in shaft-rate magnetic fields, this study introduces the Improved Exponential Triangular Optimization Algorithm (IETO). By incorporating adaptive attenuation factors, dynamic population reduction, and intelligent boundary contraction strategies, it significantly enhances the global search capability and robustness. A magnetic dipole localization model is developed, and comparative simulations show that IETO achieves reliable accuracy and robustness under low signal-to-noise ratio (SNR) conditions, reducing localization error by 7.82% compared with the conventional Exponential Triangular Optimization Algorithm (ETO). The effects of base station deployment, number of stations, and sea depth on localization performance are further examined, and the capability of IETO for dynamic target tracking is verified. Preliminary sea trial results confirm the practical feasibility and engineering applicability of the proposed method. Full article

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

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30 pages, 8901 KB

Open AccessArticle

Research on Hydrodynamic Characteristics and Drag Reduction Optimization of Drillships with Moonpools

by Junming Hu, Chengshuai Song, Jiaxian Deng, Jiaxia Wang, Xiaojie Zhao and Daiyu Zhang

J. Mar. Sci. Eng. 2026, 14(2), 215; https://doi.org/10.3390/jmse14020215 - 20 Jan 2026

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Abstract

This paper analyzes the influence of moonpools on the hydrodynamic performance of drillships using the Reynolds-averaged Navier–Stokes (RANS) method. A three-dimensional numerical wave tank is established to realize regular waves and to perform prediction and validation of the KCS ship’s performance in calm [...] Read more.

This paper analyzes the influence of moonpools on the hydrodynamic performance of drillships using the Reynolds-averaged Navier–Stokes (RANS) method. A three-dimensional numerical wave tank is established to realize regular waves and to perform prediction and validation of the KCS ship’s performance in calm water and head seas. After selecting optimal moonpool configurations under calm conditions, seakeeping analyses for a rectangular-moonpool drillship in waves and drag-reduction optimization in calm water and head seas are conducted. The comparative analysis shows that in calm-water navigation, different moonpool shapes lead to different added-resistance effects, and the drillship with a rectangular moonpool shows overall better performance in resistance and running attitude; the added resistance due to the moonpool mainly originates from the additional residual resistance. The sustained energy supply to the clockwise vortex within the moonpool is maintained by the continuous mass exchange between the water flow beneath the ship’s bottom and the water inside the moonpool. Under regular waves, the presence of a moonpool leads to an increase in the total resistance experienced by the drillship. A flange device can effectively reduce the mean amplitude of waves inside the moonpool, and when the flange is installed 10 mm above the still water level with a length of 120 mm, its drag-reduction effect is better. The flange structure can effectively improve the hydrodynamic characteristics of the drillship in waves. The numerical conclusions provide a reference value for the engineering application of drillships with moonpool structures. Full article

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

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21 pages, 6017 KB

Open AccessArticle

A New Ship Trajectory Clustering Method Based on PSO-DBSCAN

by Zhengchuan Qin and Tian Chai

J. Mar. Sci. Eng. 2026, 14(2), 214; https://doi.org/10.3390/jmse14020214 - 20 Jan 2026

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Abstract

With the rapid growth of vessel traffic and the widespread adoption of the Automatic Identification System (AIS) in recent years, analyzing maritime traffic flow characteristics has become an essential component of modern maritime supervision. Clustering analysis is one of the primary data-mining approaches [...] Read more.

With the rapid growth of vessel traffic and the widespread adoption of the Automatic Identification System (AIS) in recent years, analyzing maritime traffic flow characteristics has become an essential component of modern maritime supervision. Clustering analysis is one of the primary data-mining approaches used to extract traffic patterns from AIS data. Addressing the challenge of assigning appropriate weights to the multidimensional features in AIS trajectories, namely latitude and longitude, speed over ground (SOG), and course over ground (COG). This study introduces an adaptive parameter optimization mechanism based on evolutionary algorithms. Specifically, Particle Swarm Optimization (PSO), a representative swarm intelligence algorithm, is employed to automatically search for the optimal feature-distance weights and the core parameters of Density-Based Spatial Clustering of Applications with Noise (DBSCAN), enabling dynamic adjustment of clustering thresholds and global optimization of model performance. By designing a comprehensive clustering evaluation index as the objective function, the proposed method achieves optimal parameter allocation in a multidimensional similarity space, thereby uncovering maritime traffic clusters that may be overlooked when relying on single-dimensional features. The method is validated using AIS trajectory data from the Xiamen Port area, where 15 traffic clusters were successfully identified. Comparative experiments with two other clustering algorithms demonstrate the superior performance of the proposed approach in trajectory pattern analysis, providing valuable reference for maritime regulatory and traffic management applications. Full article

(This article belongs to the Section Ocean Engineering)

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36 pages, 4550 KB

Open AccessArticle

Probabilistic Load Forecasting for Green Marine Shore Power Systems: Enabling Efficient Port Energy Utilization Through Monte Carlo Analysis

by Bingchu Zhao, Fenghui Han, Yu Luo, Shuhang Lu, Yulong Ji and Zhe Wang

J. Mar. Sci. Eng. 2026, 14(2), 213; https://doi.org/10.3390/jmse14020213 - 20 Jan 2026

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Abstract

The global shipping industry is surging ahead, and with it, a quiet revolution is taking place on the water: marine lithium-ion batteries have emerged as a crucial clean energy carrier, powering everything from ferries to container ships. When these vessels dock, they increasingly [...] Read more.

The global shipping industry is surging ahead, and with it, a quiet revolution is taking place on the water: marine lithium-ion batteries have emerged as a crucial clean energy carrier, powering everything from ferries to container ships. When these vessels dock, they increasingly rely on shore power charging systems to refuel—essentially, plugging in instead of idling on diesel. But predicting how much power they will need is not straightforward. Think about it: different ships, varying battery sizes, mixed charging technologies, and unpredictable port stays all come into play, creating a load profile that is random, uneven, and often concentrated—a real headache for grid planners. So how do you forecast something so inherently variable? This study turned to the Monte Carlo method, a probabilistic technique that thrives on uncertainty. Instead of seeking a single fixed answer, the model embraces randomness, feeding in real-world data on supply modes, vessel types, battery capacity, and operational hours. Through repeated random sampling and load simulation, it builds up a realistic picture of potential charging demand. We ran the numbers for a simulated fleet of 400 vessels, and the results speak for themselves: load factors landed at 0.35 for conventional AC shore power, 0.39 for high-voltage DC, 0.33 for renewable-based systems, 0.64 for smart microgrids, and 0.76 when energy storage joined the mix. Notice how storage and microgrids really smooth things out? What does this mean in practice? Well, it turns out that Monte Carlo is not just academically elegant, it is practically useful. By quantifying uncertainty and delivering load factors within confidence intervals, the method offers port operators something precious: a data-backed foundation for decision-making. Whether it is sizing infrastructure, designing tariff incentives, or weighing the grid impact of different shore power setups, this approach adds clarity. In the bigger picture, that kind of insight matters. As ports worldwide strive to support cleaner shipping and align with climate goals—China’s “dual carbon” ambition being a case in point—achieving a reliable handle on charging demand is not just technical; it is strategic. Here, probabilistic modeling shifts from a simulation exercise to a tangible tool for greener, more resilient port energy management. Full article

(This article belongs to the Special Issue Advanced Technologies of Ship Power Plants and Infrastructure of Seaports)

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25 pages, 3780 KB

Open AccessArticle

A Comparative CFD Study on the Wave-Making Characteristics and Resistance Performance of Two Representative Naval Vessel Designs

by Yutao Tian, Hai Shou, Sixing Guo, Zehan Chen, Zhengxun Zhou, Yuxing Zheng, Kunpeng Shi and Dapeng Zhang

J. Mar. Sci. Eng. 2026, 14(2), 212; https://doi.org/10.3390/jmse14020212 - 20 Jan 2026

Viewed by 203

Abstract

The wave-making characteristics and resistance performance of a naval vessel are fundamental to its hydrodynamic design, directly impacting its speed, stealth, and energy efficiency. To reveal the performance trade-offs inherent in different design philosophies, a systematic comparative study on the hydrodynamic performance of [...] Read more.

The wave-making characteristics and resistance performance of a naval vessel are fundamental to its hydrodynamic design, directly impacting its speed, stealth, and energy efficiency. To reveal the performance trade-offs inherent in different design philosophies, a systematic comparative study on the hydrodynamic performance of two representative mainstream naval destroyers from China and the United States was conducted using Computational Fluid Dynamics (CFD). Full-scale three-dimensional models of both vessels were established based on publicly available data. Their flow fields in calm water were numerically simulated at both economical (18 knots) and maximum (30 knots) speeds using an unsteady Reynolds-Averaged Navier–Stokes (RANS) solver, the Volume of Fluid (VOF) method for free-surface capturing, and the SST k-ω turbulence model. The performance differences were meticulously compared through qualitative observation of wave patterns, quantitative measurements (such as the transverse width of the wave-making region), and analysis of resistance data. Numerical results indicated that the wave-making generated by the vessel of the United States was more pronounced during steady navigation. To validate the reliability of the CFD results, supplementary towing tank tests were performed using a small-scale model (1.1 m in length) of the vessel from China. The test speed (1.5 m/s) was scaled to correspond to the full-scale ship speed through dimensional analysis. The experimental data showed good agreement with the simulation results, jointly confirming the aforementioned performance trade-off. This study clearly demonstrates that, at the economic speed, the design of the mainstream vessel from China tends to prioritize superior wave stealth performance at the expense of higher resistance, whereas the mainstream vessel from the U.S. exhibits the characteristics of lower resistance coupled with more significant wave-making features. These findings provide an important theoretical basis and data support for the future multi-objective optimization design of surface vessels concerning stealth, speed, and comprehensive energy efficiency. Full article

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

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23 pages, 4564 KB

Open AccessArticle

Control of Wave Energy Converters Using Reinforcement Learning

by Odai R. Bani Hani, Zeiad Khafagy, Matthew Staber, Ashraf Gaffar and Ossama Abdelkhalik

J. Mar. Sci. Eng. 2026, 14(2), 211; https://doi.org/10.3390/jmse14020211 - 20 Jan 2026

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Abstract

Efficient control of wave energy converters (WECs) is crucial for maximizing energy capture and reducing the Levelized Cost of Energy (LCoE). In this study, we employ a deep reinforcement learning (DRL) framework based on the Soft Actor-Critic (SAC) and Deep Deterministic Policy Gradient [...] Read more.

Efficient control of wave energy converters (WECs) is crucial for maximizing energy capture and reducing the Levelized Cost of Energy (LCoE). In this study, we employ a deep reinforcement learning (DRL) framework based on the Soft Actor-Critic (SAC) and Deep Deterministic Policy Gradient (DDPG) algorithms for WEC control. Our approach leverages a novel decoupled co-simulation architecture, training agents episodically in MATLAB to export a robust policy within the WEC-Sim environment. Furthermore, we utilize a rigorous benchmarking protocol to compare the SAC and DDPG agents against a classical Bang-Singular-Bang (BSB) optimal control benchmark. Evaluation under realistic, irregular Pierson-Moskowitz sea states demonstrates that the performance of the RL agents is very close to that of the BSB optimal control baseline. Monte Carlo simulations show that both the DDPG and SAC agents can perform even better than the BSB when the model of the BSB is different from the simulation environment. Full article

(This article belongs to the Special Issue Advanced Computational Intelligence and Machine Learning Methods in Marine Renewable Energy)

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18 pages, 3612 KB

Open AccessArticle

Comparison of Fixed and Adaptive Speed Control for a Flettner-Rotor-Assisted Coastal Ship Using Coupled Maneuvering-Energy Simulation

by Seohee Jang, Hyeongyo Chae and Chan Roh

J. Mar. Sci. Eng. 2026, 14(2), 210; https://doi.org/10.3390/jmse14020210 - 20 Jan 2026

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Abstract

Wind-assisted propulsion using Flettner rotors has gained attention as the shipping sector faces stricter decarbonization regulations. This study compares conventional Fixed Speed Control with Adaptive Speed Control for a 100 m coastal vessel. The proposed Adaptive Speed Control selectively activates the rotor based [...] Read more.

Wind-assisted propulsion using Flettner rotors has gained attention as the shipping sector faces stricter decarbonization regulations. This study compares conventional Fixed Speed Control with Adaptive Speed Control for a 100 m coastal vessel. The proposed Adaptive Speed Control selectively activates the rotor based on relative wind conditions and adjusts rotor speed according to the surge-direction projection of Magnus force. A simulation framework based on the MMG maneuvering model evaluates path-following performance, fuel consumption, and annual performance indicators. Results show that Adaptive Speed Control achieves 18.84% reduction in fuel consumption, corresponding to annual savings of 212.02 tons of fuel, USD 190,823 in OPEX, and 679.76 tons of CO₂ emissions. Selective rotor operation reduces the Fatigue Damage Index by approximately 89%, resulting in 84.48% reduction in annual maintenance costs. Unwanted lateral forces and yaw disturbances are mitigated, improving path-following and maneuvering stability. These findings demonstrate that situationally aware Adaptive Speed Control improves energy efficiency and operational characteristics of Flettner-rotor-assisted propulsion systems while maintaining maneuvering performance, providing practical guidance for wind-assisted ship operation under realistic coastal conditions. Full article

(This article belongs to the Special Issue Green Energy with Advanced Propulsion Systems for Net-Zero Shipping)

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14 pages, 4934 KB

Open AccessArticle

Optimal Schemes for the Enrichment Zones of Co-Rich Ferromanganese Crusts on Seamounts

by Yonggang Liu, Yong Yang, Gaowen He, Zhenquan Wei, Weilin Ma, Kehong Yang, Donghong Liang, Shuang Hong and Ranran Du

J. Mar. Sci. Eng. 2026, 14(2), 209; https://doi.org/10.3390/jmse14020209 - 20 Jan 2026

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Abstract

The optimization of enrichment zones for Co-rich crusts involves multiple factors such as crust thickness, elemental content, topography, slope, and biological distribution, making it a complicated research endeavor. Based on survey data from the contract area, the present study pioneers the integration of [...] Read more.

The optimization of enrichment zones for Co-rich crusts involves multiple factors such as crust thickness, elemental content, topography, slope, and biological distribution, making it a complicated research endeavor. Based on survey data from the contract area, the present study pioneers the integration of environmental factors into enrichment zone selection. It conducts a comprehensive analysis of resource, environment, and mining considerations, alongside optimization methodologies. Quantitative indicators for resource, environment, and mining are spatially correlated and assigned to corresponding grid cells. A weighted scoring method is proposed to compare enrichment zone selection results under different weightings, finally forming the optimal enrichment zone selection scheme. This scheme fully achieves the maximization of resource reserves, the protection of biological communities, and the safeguarding of future mineral development. It also provides technical reference for enrichment zone selection of deep-sea minerals such as polymetallic nodules and hydrothermal sulphides. Full article

(This article belongs to the Section Geological Oceanography)

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32 pages, 8469 KB

Open AccessArticle

Fused Geophysical–Contrastive Learning Model for CYGNSS-Based Sea Surface Wind Speed Retrieval in Typhoon Regions

by Yun Zhang, Zelong Teng, Shuhu Yang, Qingjing Shi, Jiaying Li, Fei Guo, Bo Peng, Yanling Han and Zhonghua Hong

J. Mar. Sci. Eng. 2026, 14(2), 208; https://doi.org/10.3390/jmse14020208 - 20 Jan 2026

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Abstract

Global Navigation Satellite System Reflectometry (GNSS-R) provides a vital means for sea surface wind speed retrieval, yet its application under extreme typhoon conditions remains challenging. Conventional geophysical models (GMFs) saturate in high wind speed regimes (>20 m/s), and deep learning models (e.g., CNNs) [...] Read more.

Global Navigation Satellite System Reflectometry (GNSS-R) provides a vital means for sea surface wind speed retrieval, yet its application under extreme typhoon conditions remains challenging. Conventional geophysical models (GMFs) saturate in high wind speed regimes (>20 m/s), and deep learning models (e.g., CNNs) are constrained by data sparsity and feature complexity in typhoon environments. To address these issues, we propose a Comparative Learning method of CNN-Transformer with GMF fusion (CLCTG). The CNN branch extracts local coupling patterns, the Transformer branch models global dependencies, and Kullback–Leibler (KL) divergence loss is used for contrastive learning to heighten sensitivity to complex typhoon wind fields. The GMF branch serves as a physical reference/anchor in the low- to moderate-wind-speed range (<20 m/s) to guide the learning of data-driven branches and avoid overfitting by any single data-driven path. The adaptive fusion branch dynamically reweights the three branch outputs, combining local statistical characteristics to improve performance over approximately 0–30 m/s and extending the range of reliable GNSS-R retrieval from about 20 m/s to about 30 m/s; it should be noted that CLCTG exhibits a performance bottleneck in the extreme >30 m/s range. To further improve high-wind-speed predictions, we introduce environmental features based on their correlation with wind speed; ablation experiments demonstrate that the combined use of environmental parameters and CYGNSS features maximizes overall accuracy. Testing on five typhoons from the Eastern and Western Hemispheres confirms CLCTG’s generalization across diverse geographic contexts, and branch-wise comparisons validate its structural advantages. Buoy observations show peripheral errors below 3 m/s and physically consistent wind speed gradients in the core region. These results indicate that multi-source fusion of CYGNSS and environmental data, coupled with contrastive learning and physical reference, offers a reliable and efficient solution for typhoon wind speed retrieval. Full article

(This article belongs to the Section Physical Oceanography)

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30 pages, 3335 KB

Open AccessArticle

Quantitative Approach to the Preliminary Risk Analysis of Environmental Contamination Caused by Oil Spills from Offshore Oil and Gas Installations

by Sarah Bonvicini, Costanza Martina and Valerio Cozzani

J. Mar. Sci. Eng. 2026, 14(2), 207; https://doi.org/10.3390/jmse14020207 - 20 Jan 2026

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Abstract

Despite improvements in oil spill prevention, recent data confirm that oil releases at sea are still a concern due to the severe environmental contamination potential. Regulations and standards addressing the safety of offshore oil and gas operations against major accident hazards require assessing [...] Read more.

Despite improvements in oil spill prevention, recent data confirm that oil releases at sea are still a concern due to the severe environmental contamination potential. Regulations and standards addressing the safety of offshore oil and gas operations against major accident hazards require assessing and minimizing the risk to the environment caused by oil spills, as well as proving the effectiveness of emergency response plans. The present study proposes an innovative approach to the preliminary risk analysis of environmental contamination due to offshore oil spills, capable of orienting the engineering design of offshore installations and assessing the risk mitigation derived from the introduction of different safety barriers and emergency response strategies. New specific risk indexes and a novel procedure for their calculation were developed. The risk indexes are based on both the frequencies and the consequences of the spills, quantified as oil masses in each marine compartment. The approach allowed for obtaining robust risk indexes, also suitable for guiding the application of detailed oil spill risk assessment methods. A case study is presented to demonstrate the potential of the new approach. Full article

(This article belongs to the Special Issue Risk Assessment and Mitigation Strategies in Offshore Petroleum)

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20 pages, 3517 KB

Open AccessArticle

Size-Specific Phytoplankton Pigment Characteristics in Jaran and Hansan Bays Based on HPLC Analysis

by Ye Hwi Kim, Seung Min Lee, Jin Ho Kim, Yejin Kim, Sanghoon Park, Jaesoon Kim, Hayoung Choi, Hyo-Keun Jang, Myung Joon Kim, Dabin Lee, Yoon Ji Lee, Jae Hyung Lee and Sang Heon Lee

J. Mar. Sci. Eng. 2026, 14(2), 206; https://doi.org/10.3390/jmse14020206 - 20 Jan 2026

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Abstract

This study investigated the spatial and seasonal dynamics of phytoplankton communities in Jaran Bay, inner Hansan Bay, and outer Hansan Bay, with particular emphasis on size structure and pigment-based indicators of productivity and physiological status. Water sampling was conducted during May, August, and [...] Read more.

This study investigated the spatial and seasonal dynamics of phytoplankton communities in Jaran Bay, inner Hansan Bay, and outer Hansan Bay, with particular emphasis on size structure and pigment-based indicators of productivity and physiological status. Water sampling was conducted during May, August, and October in 2020, 2022, and 2023 and phytoplankton communities were analyzed using size-fractionated chlorophyll a measurements and high-performance liquid chromatography (HPLC) pigment analysis. Chlorophyll a concentrations exhibited pronounced seasonality, with consistently elevated values in August across all bays. Diatoms were predominant throughout the study period; however, their relative contribution declined in outer Hansan Bay during summer, coinciding with increased contributions from cryptophytes and cyanobacteria. Size-fractionated analyses revealed that large-sized phytoplankton (>20 µm) predominantly consisted of diatoms, whereas small-sized phytoplankton (<20 µm) were composed of diatoms and cryptophytes. Comparisons between fluorometric and pigment-based approaches indicated that pigment-based diagnostics overestimated microphytoplankton contributions, attributable to the presence of small-sized diatoms. Pigment indices further revealed that large-sized phytoplankton were characterized by higher photosynthetic carotenoid concentrations and lower photoprotective carotenoid ratios, indicative of enhanced photosynthetic activity and productivity. Overall, these findings highlight the critical role of phytoplankton size structure in regulating productivity and physiological responses in aquaculture-dominated coastal bays. Full article

(This article belongs to the Special Issue Marine Microalgae: Taxonomy, Diversity and Biogeography)

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J. Mar. Sci. Eng., Volume 14, Issue 2 (January-2 2026) – 126 articles

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