Journal of Marine Science and Engineering

15 pages, 2690 KiB

Open AccessArticle

Analysis on Inner Flow Field and Hydrodynamic Force on Flexible Mining Pipeline Under Bending States

by Wen-Hua Wang, Lei Wang, Chuang Liu, Li-Jian Wang, Zi-Han Zhao, Lei-Lei Dong, Gang Liu, Ying-Ying Wang, Hai-Bo Sun and Kun Li

J. Mar. Sci. Eng. 2025, 13(8), 1599; https://doi.org/10.3390/jmse13081599 - 21 Aug 2025

Viewed by 152

Abstract

To investigate the internal flow characteristics of particles during hydraulic lifting in deep-sea mining risers, this study developed a three-dimensional curved riser multiphase flow model based on the Eulerian–Eulerian framework and the RNG k-ε turbulence model. The effects of particle distribution [...] Read more.

To investigate the internal flow characteristics of particles during hydraulic lifting in deep-sea mining risers, this study developed a three-dimensional curved riser multiphase flow model based on the Eulerian–Eulerian framework and the RNG k-ε turbulence model. The effects of particle distribution and pressure loss in the curved section, as well as the influence of curvature radius, were analyzed. Results indicate that particle distributions take concave circular or crescent-shaped patterns, becoming more uniform with larger curvature radii. Pressure on the extrados is consistently greater than on the intrados, with pressure loss increasing in the bend and peaking at the midpoint. A larger curvature radius leads to greater total pressure loss but lower frictional loss. Additionally, the bend experiences a restoring force toward the vertical position, which increases as the curvature radius decreases. Full article

(This article belongs to the Section Ocean Engineering)

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28 pages, 11764 KiB

Open AccessArticle

Study on Cavitation Flow Structure Evolution in the Hump Region of Water-Jet Pumps Under the Valley Condition

by Yingying Zheng, Yun Long, Min Liu, Hanqiao Han, Kai Wang, Jinqing Zhong and Yun Long

J. Mar. Sci. Eng. 2025, 13(8), 1598; https://doi.org/10.3390/jmse13081598 - 21 Aug 2025

Viewed by 76

Abstract

During the hydraulic performance experiment, significant vibration and noise were observed in the mixed-flow pump operating in the hump region. Cavitation occurrence in the impeller flow channels was confirmed through the transparent chamber. To analyze cavitation flow structure evolution in the mixed-flow pump, [...] Read more.

During the hydraulic performance experiment, significant vibration and noise were observed in the mixed-flow pump operating in the hump region. Cavitation occurrence in the impeller flow channels was confirmed through the transparent chamber. To analyze cavitation flow structure evolution in the mixed-flow pump, this paper integrates numerical and experimental approaches, capturing cavitation flow structures under the valley condition through high-speed photography technology. During the various stages of cavitation development, the cavitation forms are mostly vortex cavitation, cloud cavitation, and perpendicular vortex cavitation. Impeller rotation induces downstream transport of shedding cloud cavitation shedding structures. Flow blockage occurs when cavitation vortexes obstruct specific passages, accelerating cavitation growth that culminates in head reduction through energy dissipation mechanisms. Vortex evolution analysis revealed enhanced density of small-scale vortex structures with stronger localized core intensity in the impeller and diffuser. Despite larger individual vortex scales, reduced core intensity persists throughout the full flow domain. Concurrently, velocity profile characteristics across flow rates and blade sections (spanwise from tip to root) indicate heightened predisposition to flow separation, recirculation zones, and low-velocity regions during off-design operation. This study provides scientific guidance for enhancing anti-cavitation performance in the hump region. Full article

(This article belongs to the Section Ocean Engineering)

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21 pages, 4204 KiB

Open AccessArticle

Life on Plastics: Deep-Sea Foraminiferal Colonization Patterns and Reproductive Morphology

by Ashley M. Burkett

J. Mar. Sci. Eng. 2025, 13(8), 1597; https://doi.org/10.3390/jmse13081597 - 21 Aug 2025

Viewed by 145

Abstract

Plastic debris has become a persistent feature of deep-sea ecosystems, yet its role as a habitat for calcifying organisms remains poorly understood. Foraminifera colonization has been observed in significant numbers on plastic surfaces, suggesting that these materials serve as novel and significant deep-sea [...] Read more.

Plastic debris has become a persistent feature of deep-sea ecosystems, yet its role as a habitat for calcifying organisms remains poorly understood. Foraminifera colonization has been observed in significant numbers on plastic surfaces, suggesting that these materials serve as novel and significant deep-sea colonization sites for these abundant calcifying organisms. This study uses deep-sea experimental plastic substrates to examine the colonization and reproductive morphology of the benthic foraminifera Lobatula wuellerstorfi across three locations: Station M (4000 m), Oregon OOI (575 m), and Southern Hydrate Ridge (774 m). A total of 482 individuals were analyzed for morphometric traits, including proloculus diameter, to investigate reproductive morphotypes. The Oregon samples displayed a clear bimodal proloculus size distribution, consistent with alternating reproductive strategies, while Station M populations exhibited a broader, less defined bimodal distribution skewed toward megalospheric forms. A weak but significant increase in proloculus diameter over deployment duration was observed at Station M, suggesting a possible influence of experiment duration and/or substrate maturity and environmental conditions. These findings demonstrate that plastics can serve as persistent colonization sites for deep-sea foraminifera, offering a unique experimental platform to investigate benthic population dynamics, ecological plasticity, and potential geochemical implications, as well as the broader impacts of foraminifera on deep-sea biodiversity and biogeochemical cycling. Full article

(This article belongs to the Special Issue Effects of Ocean Plastic Pollution on Aquatic Life)

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21 pages, 6924 KiB

Open AccessArticle

The Dynamic Response of a Coral Sand Site–Underground Structure System Under Multidimensional Seismic Excitation

by Zixuan Yang, Xiaorui Xie and Wei Ren

J. Mar. Sci. Eng. 2025, 13(8), 1596; https://doi.org/10.3390/jmse13081596 - 21 Aug 2025

Viewed by 123

Abstract

Seismic response analysis of underground structures at coral sand sites is a critical component in ensuring the structural safety of island reef engineering. Current experimental studies in this field have primarily focused on unidirectional seismic excitation. To investigate the seismic response differences under [...] Read more.

Seismic response analysis of underground structures at coral sand sites is a critical component in ensuring the structural safety of island reef engineering. Current experimental studies in this field have primarily focused on unidirectional seismic excitation. To investigate the seismic response differences under multidirectional seismic loading, this study designed a series of shaking table tests under unidirectional, bidirectional, and triaxial loading schemes. The seismic responses of underground structures and coral sand foundations were compared under different loading conditions, including boundary effects, ground and structural accelerations, Fourier spectra, and structural strains. The results indicate that the soil–structure system exhibits responses in the non-excitation directions during the shaking table tests. Compared to the excitation direction, boundary effects are more pronounced in the non-excitation directions, with vibrations in these directions primarily concentrated in the high-frequency range (16–20 Hz). The ground acceleration amplification factors in the X-, Y-, and Z-directions in different loading directions are 0.9–1.3, 1.4–2, and 3.4–3.7, respectively, showing significant differences. Under triaxial loading, the peak strain in the underground structure is significantly higher than that under unidirectional loading. Full article

(This article belongs to the Topic Coastal Engineering: Past, Present and Future)

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4 pages, 157 KiB

Open AccessEditorial

Wave/Current–Structure–Seabed Interactions Around Offshore Foundations

by Wengang Qi, Shengjie Rui and Zhen Guo

J. Mar. Sci. Eng. 2025, 13(8), 1595; https://doi.org/10.3390/jmse13081595 - 21 Aug 2025

Viewed by 202

Abstract

The rapid expansion of the offshore energy infrastructure, including wind turbines, subsea pipelines, and marine platforms, has underscored the critical need to overcome the challenges presented by harsh marine environments [...] Full article

(This article belongs to the Special Issue Wave/Current–Structure–Seabed Interactions around Offshore Foundations)

24 pages, 5025 KiB

Open AccessArticle

Upper-Bound Stability Analysis of Cracked Embankment Slopes with Inclined Interlayers Subject to Pore Water Pressure

by Jingwu Zhang, Zehao Yu and Jinxiang Yi

J. Mar. Sci. Eng. 2025, 13(8), 1594; https://doi.org/10.3390/jmse13081594 - 21 Aug 2025

Viewed by 216

Abstract

This study analyzes the stability of embankment slopes with inclined interlayers and vertical tensile cracks at the crest under saturated conditions. This study first establishes a composite failure mechanism based on a finite element limit analysis; then, it derives an upper-bound solution formula [...] Read more.

This study analyzes the stability of embankment slopes with inclined interlayers and vertical tensile cracks at the crest under saturated conditions. This study first establishes a composite failure mechanism based on a finite element limit analysis; then, it derives an upper-bound solution formula for stability considering pore water pressure; and finally, it verifies the rationality of the method through case comparisons. This study finds that an increase in crack depth (H_c) causes the crack initiation position to approach the crest edge, while increases in the slope angle (β), pore water pressure coefficient (r_u), and interlayer embedment depth (d) lead to the opposite trend. Both the stability number (γH/c₁) and safety factor (F_s) decrease with the increase in the slope angle, pore water pressure coefficient, and crack depth, and they increase with the enhancement of relative soil strength and the increase in interlayer embedment depth. When cracks exist at the crest, the influence of pore water pressure on the sliding surface is diminished, while decreasing the cohesion ratio of interlayer to embankment slope soil (c₂/c₁) expands the range of the critical sliding surface. Full article

(This article belongs to the Section Coastal Engineering)

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35 pages, 3129 KiB

Open AccessArticle

Spatiotemporal Meta-Reinforcement Learning for Multi-USV Adversarial Games Using a Hybrid GAT-Transformer

by Yang Xiong, Shangwen Wang, Hongjun Tian, Guijie Liu, Zihao Shan, Yijie Yin, Jun Tao, Haonan Ye and Ying Tang

J. Mar. Sci. Eng. 2025, 13(8), 1593; https://doi.org/10.3390/jmse13081593 - 20 Aug 2025

Viewed by 121

Abstract

Coordinating Multi-Unmanned Surface Vehicle (USV) swarms in complex, adversarial maritime environments is a significant challenge, as existing multi-agent reinforcement learning (MARL) methods often fail to capture intricate spatiotemporal dependencies, leading to suboptimal policies. To address this, we propose Adv-TransAC, a novel Spatio-Temporal Meta-Reinforcement [...] Read more.

Coordinating Multi-Unmanned Surface Vehicle (USV) swarms in complex, adversarial maritime environments is a significant challenge, as existing multi-agent reinforcement learning (MARL) methods often fail to capture intricate spatiotemporal dependencies, leading to suboptimal policies. To address this, we propose Adv-TransAC, a novel Spatio-Temporal Meta-Reinforcement Learning framework. Its core innovation is a hybrid GAT-transformer architecture that decouples spatial and temporal reasoning: a Graph Attention Network (GAT) models instantaneous tactical formations, while a transformer analyzes their temporal evolution to infer intent. This is combined with an adversarial meta-learning mechanism to enable rapid adaptation to opponent tactics. In high-fidelity escort and defense simulations, Adv-TransAC significantly outperforms state-of-the-art MARL baselines in task success rate and policy robustness. The learned policies demonstrate the emergence of complex cooperative behaviors, such as intelligent risk-aware coordination and proactive interception maneuvers. The framework’s practicality is further validated by a communication-efficient federated optimization architecture. By effectively modeling spatiotemporal dynamics and enabling rapid adaptation, Adv-TransAC provides a powerful solution that moves beyond reactive decision-making, establishing a strong foundation for next-generation, intelligent maritime platforms. Full article

(This article belongs to the Special Issue Advanced Control Strategies for Autonomous Maritime Systems)

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22 pages, 3781 KiB

Open AccessArticle

Fault-Tolerant Trajectory Tracking Control for a Differential-Driven Unmanned Surface Vehicle with Propeller Faults

by Yuanbo Su, Renhai Yu, Wanyu Tang and Tieshan Li

J. Mar. Sci. Eng. 2025, 13(8), 1592; https://doi.org/10.3390/jmse13081592 - 20 Aug 2025

Viewed by 220

Abstract

This article investigates the problem of adaptive fault-tolerant trajectory tracking control for a differential-driven unmanned surface vehicle (USV) with propeller faults. A new USV control system considering a propeller servo loop is established, which is composed of kinematics, kinetics including unhealthy surge force [...] Read more.

This article investigates the problem of adaptive fault-tolerant trajectory tracking control for a differential-driven unmanned surface vehicle (USV) with propeller faults. A new USV control system considering a propeller servo loop is established, which is composed of kinematics, kinetics including unhealthy surge force and yaw moment, and propeller motor shaft speed dynamics. Firstly, the control design of the kinematic level derives the virtual surge speed and yaw rate, which can accurately guide the tracking design of the kinetic level. Secondly, by estimating the bound of the unknown propeller fault parameters, the virtual fault-tolerant control laws are constructed in the kinetic level, which can generate the desired motor angular shaft speeds with an active compensation feature. Thirdly, in the control design of the propeller servo loop, the command duty cycles are designed to force the actual motor shaft speeds to track the desired signals produced from the kinetic level. It can be proven that tracking errors are semiglobally ultimately uniformly bounded based on Lyapunov stability theory. Finally, simulations considering single propeller and twin propeller faults prove the validity of the developed method. Full article

(This article belongs to the Special Issue Control and Optimization of Ship Propulsion System)

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5 pages, 163 KiB

Open AccessEditorial

Application of Deep Learning in Underwater Image Processing

by Chia-Hung Yeh, Chua-Chin Wang and Guo-Shiang Lin

J. Mar. Sci. Eng. 2025, 13(8), 1591; https://doi.org/10.3390/jmse13081591 - 20 Aug 2025

Viewed by 109

Abstract

The ocean covers a significant portion of the Earth’s surface and harbors abundant natural resources, meaning that underwater exploration is of significant importance [...] Full article

(This article belongs to the Special Issue Application of Deep Learning in Underwater Image Processing)

22 pages, 2073 KiB

Open AccessReview

Up-to-Date Scoping Review of Object Detection Methods for Macro Marine Debris

by Zoe Moorton, Kamlesh Mistry, Rebecca Strachan and Shanfeng Hu

J. Mar. Sci. Eng. 2025, 13(8), 1590; https://doi.org/10.3390/jmse13081590 - 20 Aug 2025

Viewed by 291

Abstract

Being able to accurately identify litter in a marine environment is crucial to cleaning up our seas and oceans. Research into object detection techniques to support this identification has been underway for over two decades. However, there have been substantial advancements in the [...] Read more.

Being able to accurately identify litter in a marine environment is crucial to cleaning up our seas and oceans. Research into object detection techniques to support this identification has been underway for over two decades. However, there have been substantial advancements in the past five years due to the implementation of deep learning techniques. Following the PRISMA-ScR guidelines, we provide an in-depth summary and analysis of recent and significant research contributions to the object detection of macro marine debris. From cross-referencing the results of the literature review, we deduce that there is currently no benchmarked framework for evaluating and comparing computer vision techniques for marine environments. Subsequently, we use the results from our analysis to provide a suggested checklist for future researchers in this field. Furthermore, many of the respected researchers in this field have advocated for a comprehensive database of underwater debris to support research developments in intelligent object detection and identification. Full article

(This article belongs to the Special Issue Underwater Observation Technology in Marine Environment)

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16 pages, 4447 KiB

Open AccessArticle

Evaluation of Free-Surface Exposure Effects on Tidal Turbine Performance Using CFD

by Gyeongseo Min, Wooseok Choi, Haechan Yun, Younguk Do, Kangmin Kim, Weichao Shi, Saishuai Dai, Daejeong Kim and Soonseok Song

J. Mar. Sci. Eng. 2025, 13(8), 1589; https://doi.org/10.3390/jmse13081589 - 19 Aug 2025

Viewed by 212

Abstract

Tidal turbines represent a promising renewable energy source, generating power from ocean currents. However, due to tidal range variations, they sometimes become partially exposed to the free surface. When this occurs, the turbine experiences reduced power generation and unsteady torque caused by the [...] Read more.

Tidal turbines represent a promising renewable energy source, generating power from ocean currents. However, due to tidal range variations, they sometimes become partially exposed to the free surface. When this occurs, the turbine experiences reduced power generation and unsteady torque caused by the asymmetric flow. Such conditions can lead to long-term degradation of turbine performance and reliability. From this perspective, a key question arises regarding how significantly power generation differs when turbines are exposed to the free surface. This study was conducted with the objective of quantitatively evaluating the differences in power generation and torque acting on the turbine due to free-surface exposure, in order to address this question. Numerical simulations considering free-surface exposure effects were developed to quantitatively assess these phenomena through Computational Fluid Dynamics (CFD). Additionally, this numerical model was validated by comparison against experimental data and verified by convergence tests. The results revealed that the tidal turbine exhibited power generation differences ranging from a maximum of 45% to a minimum of 0.44%, depending on the degree of free-surface exposure. These findings are expected to serve as valuable indicators for power generation when operating tidal turbines. Full article

(This article belongs to the Special Issue Marine CFD: From Resistance Prediction to Environmental Innovation)

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25 pages, 2609 KiB

Open AccessArticle

Dynamic Event-Triggering Surrounding Control for Multi-USVs Under FDI Attacks via Adaptive Dynamic Programming

by Dongwei Wang, Ying Zhang and Qing Hu

J. Mar. Sci. Eng. 2025, 13(8), 1588; https://doi.org/10.3390/jmse13081588 - 19 Aug 2025

Viewed by 121

Abstract

This paper investigates the surrounding control problem of multiple unmanned surface vehicles (USVs) against false data injection (FDI) attacks and proposes a learning-based prescribed performance control (PPC) integrated with a dynamic event-triggering (DET) mechanism. First, a predefined-time observer (PTO) is designed to estimate [...] Read more.

This paper investigates the surrounding control problem of multiple unmanned surface vehicles (USVs) against false data injection (FDI) attacks and proposes a learning-based prescribed performance control (PPC) integrated with a dynamic event-triggering (DET) mechanism. First, a predefined-time observer (PTO) is designed to estimate the injected false data. Then, the constrained surrounding tracking error of multi-USVs is first formulated based on an exponential prescribed performance function. To facilitate the control law design, the constrained surrounding problem is transformed into an unconstrained space using a hyperbolic tangent function. Based on adaptive dynamic programming (ADP) and the DET mechanism, a prescribed performance time-varying surrounding control scheme is developed. Finally, the effectiveness and superiority of the proposed control strategy are demonstrated through rigorous theoretical analysis and simulation experiments, while Zeno behavior in the event-triggered mechanism is excluded. Full article

(This article belongs to the Special Issue Ship Wireless Sensor)

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21 pages, 9585 KiB

Open AccessArticle

Multi-Mode Joint Equalization Scheme for Low Frequency and Long Range Shallow Water Communications

by Shuang Xiao, Yaqi Zhang, Bin Liu, Hongyu Cui and Dazhi Gao

J. Mar. Sci. Eng. 2025, 13(8), 1587; https://doi.org/10.3390/jmse13081587 - 19 Aug 2025

Viewed by 113

Abstract

To improve the spatial processing performance in the low frequency and long range shallow water communication system, a multi-mode joint equalization scheme is proposed, which combines modal depth function estimation, mode filtering, and multi-input equalization. This method first estimates the modal depth function [...] Read more.

To improve the spatial processing performance in the low frequency and long range shallow water communication system, a multi-mode joint equalization scheme is proposed, which combines modal depth function estimation, mode filtering, and multi-input equalization. This method first estimates the modal depth function of the effective modes by Singular Value Decomposition (SVD) of Cross Spectral Density Matrix (CDSM), then separates the influence of each mode on the continuous-time signal by the vertical array mode filtering without any prior information. After these pre-processings, the separated signal is only affected by the single channel mode, and the output Signal-to-Noise Ratio (SNR) is enhanced, and channel delay spread is reduced simultaneously. All the separated parts are then sent to a multi-input equalizer to compensate for the channel fading between different modes.Simulation results verify that compared with single channel equalization after beamforming and multichannel equalization, the proposed multi-mode joint equalization can obtain 3 dB and 6 dB gain, respectively. Experimental results also show that the proposed equalization can achieve lower Bit Error Rate (BER) and higher output SNR. Full article

(This article belongs to the Topic Advances in Underwater Signal Processing and Communication: Challenges, Innovations, and Applications)

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17 pages, 2865 KiB

Open AccessArticle

Estimation of Growth and Carrying Capacity of Porphyra spp. Under Aquaculture Conditions on the Southern Coast of Korea Using Dynamic Energy Budget (DEB)

by Dae Ho Tac, Sung Eun Park and Ji Young Lee

J. Mar. Sci. Eng. 2025, 13(8), 1586; https://doi.org/10.3390/jmse13081586 - 19 Aug 2025

Viewed by 216

Abstract

Understanding the growth dynamics and ecological constraints of Porphyra spp. is essential for optimizing sustainable seaweed aquaculture. However, most existing models lack physiological detail and exhibit limited performance under variable environmental conditions. This study developed a mechanistic Dynamic Energy Budget (DEB) model to [...] Read more.

Understanding the growth dynamics and ecological constraints of Porphyra spp. is essential for optimizing sustainable seaweed aquaculture. However, most existing models lack physiological detail and exhibit limited performance under variable environmental conditions. This study developed a mechanistic Dynamic Energy Budget (DEB) model to simulate structural biomass accumulation, carbon and nitrogen reserve dynamics, and blade area expansion of Porphyra under natural environmental conditions in Korean coastal waters. The model incorporates temperature, irradiance, and nutrient availability (NO₃⁻ and CO₂) as environmental drivers and was implemented using a forward difference numerical scheme. Field data from Beein Bay were used for model calibration and validation. Simulations showed good agreement with the observed biomass, reserve content, and blade area, with root-mean-square error (RMSE) typically within ±10%. Sensitivity analysis identified temperature-adjusted carbon assimilation and nitrogen uptake as the primary drivers of growth. The model was further used to estimate dynamic carrying capacity, revealing seasonal thresholds for sustainable biomass under current farming practices. Although limitations remain—such as the exclusion of reproductive allocation and tissue loss—the results demonstrate that DEB theory provides a robust framework for modeling Porphyra aquaculture. This approach supports scenario testing, spatial planning, and production forecasting, and it is adaptable for ecosystem-based management including integrated multi-trophic aquaculture (IMTA) and climate adaptation strategies. Full article

(This article belongs to the Section Marine Environmental Science)

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18 pages, 1114 KiB

Open AccessArticle

Calibration Procedures for NO_x Emissions Model of a High-Speed Marine Diesel Engine Using Optimization Procedures

by Mina Tadros and Evangelos Boulougouris

J. Mar. Sci. Eng. 2025, 13(8), 1585; https://doi.org/10.3390/jmse13081585 - 19 Aug 2025

Viewed by 203

Abstract

Controlling nitrogen oxide (NO_x) emissions is a critical priority for the maritime industry, driven by increasingly stringent international maritime organization (IMO) Tier III regulations and the sector’s broader decarbonization efforts. Accurate prediction and minimization of NO_x emissions require well-calibrated engine [...] Read more.

Controlling nitrogen oxide (NO_x) emissions is a critical priority for the maritime industry, driven by increasingly stringent international maritime organization (IMO) Tier III regulations and the sector’s broader decarbonization efforts. Accurate prediction and minimization of NO_x emissions require well-calibrated engine models that reflect real-world operating behavior under varied conditions. This study presents a robust calibration methodology for the NO_x emissions model of a high-speed dual-fuel marine engine, using a 1D engine simulation platform (WAVE 2025.1) integrated with a nonlinear optimization algorithm (fmincon in MATLAB R2025a). The calibration focuses on tuning the extended Zeldovich mechanism by empirically adjusting the Arrhenius equation coefficients to achieve a weighted sum of NO_x and unburned hydrocarbon (HC) emissions below the 7.2 g/kWh regulatory threshold. The proposed approach reduces the need for extensive experimental data while maintaining high predictive accuracy. Simulation results confirm compliance with IMO regulations across multiple engine loads defined by the E3 test cycle. A sensitivity analysis further revealed that while the pre-exponent multiplier (ARC1) plays a critical role in influencing NO_x emissions at high loads, the exponent multiplier (AERC1) has an even more significant impact across the full load range, making its precise calibration essential for robust emissions modeling. The calibrated NO_x emissions model not only ensures realistic emissions estimation but also provides a reliable foundation for further research, such as dual-fuel performance studies, and can be effectively integrated into future engine optimization tasks under different operating conditions. Full article

(This article belongs to the Special Issue Performance and Emission Characteristics of Marine Engines)

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24 pages, 7483 KiB

Open AccessArticle

Integration of the CEL and ML Methods for Landing Safety Prediction and Optimization of Full-Scale Track Design in a Deep-Sea Mining Vehicle

by Yifeng Zeng, Zongxiang Xiu, Lejun Liu, Qiuhong Xie, Yongfu Sun, Jianghui Yang and Xingsen Guo

J. Mar. Sci. Eng. 2025, 13(8), 1584; https://doi.org/10.3390/jmse13081584 - 19 Aug 2025

Viewed by 207

Abstract

Ensuring the safe landing of deep-sea mining vehicles (DSMVs) on soft seabed sediments is critical for the stability and operational reliability of subsea mineral extraction. However, deep-sea sediments, particularly in polymetallic nodule regions, are characterized by low shear strength, high compressibility, and rate-dependent [...] Read more.

Ensuring the safe landing of deep-sea mining vehicles (DSMVs) on soft seabed sediments is critical for the stability and operational reliability of subsea mineral extraction. However, deep-sea sediments, particularly in polymetallic nodule regions, are characterized by low shear strength, high compressibility, and rate-dependent behavior, posing significant challenges for full-scale experimental investigation and predictive modeling. To address these limitations, this study develops a high-fidelity finite element simulation framework based on the Coupled Eulerian–Lagrangian (CEL) method to model the landing and penetration process of full-scale DSMVs under various geotechnical conditions. To overcome the high computational cost of FEM simulations, a data-driven surrogate model using the random forest algorithm is constructed to predict the normalized penetration depth based on key soil and operational parameters. The proposed hybrid FEM–ML approach enables efficient multiparameter analysis and provides actionable insights into the complex soil–structure interactions involved in DSMV landings. This methodology offers a practical foundation for engineering design, safety assessment, and descent planning in deep-sea mining operations. Full article

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

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29 pages, 2939 KiB

Open AccessArticle

Scour Near Offshore Structures—Part 2: Practical Scour Model

by L. C. van Rijn and K. L. Meijer

J. Mar. Sci. Eng. 2025, 13(8), 1583; https://doi.org/10.3390/jmse13081583 - 18 Aug 2025

Viewed by 224

Abstract

Scour near various offshore structures has been studied by performing numerical model runs with the modified (Fortran) SEDTUBE model, as a follow-up of an earlier paper on scour near marine offshore structures. A fairly simple 1D numerical model (SEDTUBE model) for the computation [...] Read more.

Scour near various offshore structures has been studied by performing numerical model runs with the modified (Fortran) SEDTUBE model, as a follow-up of an earlier paper on scour near marine offshore structures. A fairly simple 1D numerical model (SEDTUBE model) for the computation of sand transport rates and scour depths near structures on the seabed (berms, bed protections) is proposed, tested and validated. The model domain is a stream tube (varying or constant width) including the loose seabed and the hard layers of (multiple) structures. Hence, the model computes the sediment transport along the bed and over the structure(s). The SEDTUBE model can predict the time evolution of free scour depth around rock berms; bed protections; and pile-type structures, as well as the edge scour further away from the pile, in unidirectional and bidirectional tidal flows (weak and strong currents) in combination with waves over a sandy sediment bed with d₅₀ in the range between 0.2 and 2 mm. Five laboratory and four field cases have been used for validation of the model. The model is much more than a scour model; it can also be used for the prediction of sedimentation in shipping channels. The model is valid for sandy beds and for mud–sand beds with slight cohesive properties. Full article

(This article belongs to the Section Coastal Engineering)

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97 pages, 35693 KiB

Open AccessReview

Australia’s Two Great Barrier Reefs: What Can ~360 Million Years of Change Teach Us?

by Gregory E. Webb

J. Mar. Sci. Eng. 2025, 13(8), 1582; https://doi.org/10.3390/jmse13081582 - 18 Aug 2025

Viewed by 584

Abstract

Coral reefs are among the most important marine habitats but face significant threats from anthropogenic sources, including climate change. This paper reviews and compares the modern Great Barrier Reef Province and the 360-million-year-old Devonian Great Barrier Reef of western Australia. Despite occurring at [...] Read more.

Coral reefs are among the most important marine habitats but face significant threats from anthropogenic sources, including climate change. This paper reviews and compares the modern Great Barrier Reef Province and the 360-million-year-old Devonian Great Barrier Reef of western Australia. Despite occurring at times with different climates, biota (both marine and terrestrial), weathering processes and marine chemistry, similar reefs were constructed under certain circumstances. Major differences in global temperature, marine carbonate saturation, sea level behavior and reef community constituents were evaluated. The comparison highlights the integration of, and interdependencies within, reef communities and the need for both carbonate producers and significant binders, whether skeletal or microbial, to construct a reef in a high-energy setting. Devonian communities with abundant corals and skeletal sponges were incapable of making modern reef types without competent binders to unify framework into rigid substrate. The current strong focus on corals and bleaching in modern reef conservation may be obscuring the equally significant issue of ocean acidification, which impacts on equally crucial framework unification, i.e., hard binding by coralline algae and microbialites and early cementation. The comparison also supports the idea that ‘empty bucket’ carbonate platform morphologies require increased accommodation from high-amplitude icehouse sea level oscillations. Full article

(This article belongs to the Special Issue Feature Review Papers in Geological Oceanography)

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13 pages, 2898 KiB

Open AccessArticle

Vertical Distribution Profiling of E. coli and Salinity in Tokyo Coastal Waters Following Rainfall Events Under Various Tidal Conditions

by Chomphunut Poopipattana, Manish Kumar and Hiroaki Furumai

J. Mar. Sci. Eng. 2025, 13(8), 1581; https://doi.org/10.3390/jmse13081581 - 18 Aug 2025

Viewed by 225

Abstract

Urban estuarine environments face increasing water safety risks due to microbial contamination from combined sewer overflows (CSOs), particularly during heavy rainfall events. In megacities like Tokyo, where waterfronts are widely used for recreation, such contamination poses significant public health risks. The challenge is [...] Read more.

Urban estuarine environments face increasing water safety risks due to microbial contamination from combined sewer overflows (CSOs), particularly during heavy rainfall events. In megacities like Tokyo, where waterfronts are widely used for recreation, such contamination poses significant public health risks. The challenge is compounded by the variability in both intensity and spatial distribution of rainfall across the catchment, combined with complex tidal dynamics making effective water quality management difficult. To address this challenge, we conducted a series of hydrodynamic–microbial fate simulations to examine the spatial and vertical behavior of Escherichia coli (E. coli) under different rainfall–tide conditions. Focusing on the Sumida River estuary, rainfall data from eight drainage areas were classified into six event types using cluster analysis. Two contrasting events were selected for detailed analysis: a light rainfall (G2, 15 mm over 13 h) and an intense event (G6, 272 mm over 34 h). Vertical water quality profiling was performed along an 8.5 km transect from the Kanda–Sumida River confluence to the Tokyo Bay Tunnel, illustrating E. coli and salinity. The results showed that the rainfall intensity and tidal phase at the event onset are critical in shaping both the magnitude and vertical distribution of microbial contamination. The intense event (G6) led to deep microbial intrusion (up to 6–7 m) and major salinity disruption, while the lighter event (G2) showed surface-layer confinement. Salinity gradients were more strongly affected during G6, indicating freshwater intrusion. Tidal phase also influenced transport: the flood-high condition retained E. coli, whereas ebb-low tides facilitated downstream flushing. These findings highlight the influence of rainfall intensity and tidal timing on microbial distribution and support the use of vertical profiling in estuarine water quality management. They also support the development of dynamic, event-based water quality risk assessment tools. With appropriate local calibration, the modeling framework is transferable to other urban estuarine systems to support proactive and adaptive water quality management. Full article

(This article belongs to the Special Issue Coastal Water Quality Observation and Numerical Modeling)

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32 pages, 1468 KiB

Open AccessArticle

Scissors Approach in Human and Equipment Reliability Vis-A-Vis the Use of Alternative Fuel in Ship Propulsion

by Bebetebe Fetimi, Byongug Jeong, Yeongmin Park and Jaehoon Jee

J. Mar. Sci. Eng. 2025, 13(8), 1580; https://doi.org/10.3390/jmse13081580 - 18 Aug 2025

Viewed by 205

Abstract

This project looks deeply at the integration of human and equipment reliability in hydrogen bunkering operations, focusing on human corrective response actions (HCRAs) to unwanted events in the process. Human responses are also actions shaped by human performance thereby not totally devoid of [...] Read more.

This project looks deeply at the integration of human and equipment reliability in hydrogen bunkering operations, focusing on human corrective response actions (HCRAs) to unwanted events in the process. Human responses are also actions shaped by human performance thereby not totally devoid of human error. The possibility of the occurrence of accidents even when both personnel and equipment are reliable draws great attention to examine human responses to occurrences in the bunkering process of hydrogen. The Cognitive Reliability and Error Analysis Method (CREAM) is adopted alongside equipment reliability data from the maritime industry to assess the connection between system performance and human decision-making in the bunkering operation process. The findings show that enhanced equipment reliability significantly improves human corrective responses, leading to great operational efficiency. This study proposes an integrated reliability framework to optimize hydrogen bunkering procedures vis-à-vis an enhanced safety response, providing recommendations for improving safety regulations, and necessitate operator training, equipment management, and risk mitigation approaches. By ensuring industrial compliance and enhancing overall reliability in ship propulsion, these insights contribute to the use of hydrogen as an alternative fuel in the maritime sector for ship propulsion. Full article

(This article belongs to the Section Ocean Engineering)

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21 pages, 3776 KiB

Open AccessArticle

An Unmanned Vessel Path Planning Method for Floating-Waste Cleaning Based on an Improved Ant Colony Algorithm

by Yong Li, Changjun Tang, Sen Yan, Ruichen Wang and Dongxu Gao

J. Mar. Sci. Eng. 2025, 13(8), 1579; https://doi.org/10.3390/jmse13081579 - 18 Aug 2025

Viewed by 227

Abstract

Efficient cleaning of floating waste using an intelligent unmanned surface vehicle is an important development trend in inland water governance. Path planning is the core of the decision-making module for unmanned surface vehicle waste cleaning and is key to achieving autonomous operation of [...] Read more.

Efficient cleaning of floating waste using an intelligent unmanned surface vehicle is an important development trend in inland water governance. Path planning is the core of the decision-making module for unmanned surface vehicle waste cleaning and is key to achieving autonomous operation of the unmanned surface vehicle. However, due to the complexity and dynamic changes of the water surface environment, unmanned surface vehicle path planning methods for floating waste face challenges such as small size, uncertainty, and uneven distribution of floating waste. In response to the above issues, this article studies the problem of insufficient integration and low efficiency between existing path planning algorithms and target-perception modules, and designs an efficient overall path planning method for floating-waste cleaning by an unmanned surface vehicle. This method transforms the path planning problem of floating-waste cleaning unmanned surface vehicle into a Traveling Salesman Problem by setting global patrol points and tracking local targets, and proposes an improved ant colony algorithm, IACO, to solve the Traveling Salesman Problem. This article is based on the TSPLIB dataset and practical applications for experiments. The experimental results show that the proposed method has average optimal path lengths of 75.930 m, 446.555 m, and 703.759 m on the Ulysses22, eil51, and st70 datasets, respectively, which are reduced by 0.355 m, 4.108 m, and 13.575 m compared to the benchmark. Full article

(This article belongs to the Section Ocean Engineering)

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30 pages, 6817 KiB

Open AccessArticle

Numerical Study on Non-Icebreaking Ship Maneuvering in Floating Ice Based on Coupled NDEM–MMG Modeling

by Deling Wang, Luyuan Zou, Zhiheng Zhang and Xinqiang Chen

J. Mar. Sci. Eng. 2025, 13(8), 1578; https://doi.org/10.3390/jmse13081578 - 17 Aug 2025

Viewed by 233

Abstract

The maneuvering performance of ships in marginal ice zones is critical for navigational safety, yet most existing studies focus on icebreaking vessels. This study develops a coupled numerical framework that integrates the Non-Smooth Discrete Element Method (NDEM) for simulating ship–ice interactions with the [...] Read more.

The maneuvering performance of ships in marginal ice zones is critical for navigational safety, yet most existing studies focus on icebreaking vessels. This study develops a coupled numerical framework that integrates the Non-Smooth Discrete Element Method (NDEM) for simulating ship–ice interactions with the three-degree-of-freedom MMG model for ship dynamics. The framework was applied to an S175 container ship, and numerical simulations were conducted for turning circle and Zig-Zag maneuvers under varying ice concentrations (0–60%), floe sizes, and rudder angles. NDEM efficiently handles complex, high-frequency multi-body collisions with larger time steps compared to conventional DEM or CFD–DEM approaches, enabling large-scale simulations of realistic ice conditions. Results indicate that increasing ice concentration from 0% to 60% reduces the turning diameter from 4.11L to 3.21L and decreases steady turning speed by approximately 53%. Larger floes form stable force chains that restrict lateral motion, while higher rudder angles improve responsiveness but may induce dynamic instability. These findings improve understanding of non-icebreaking ship maneuverability in ice and provide practical guidance for safe and efficient Arctic navigation. Full article

(This article belongs to the Special Issue Safe Maneuvering, Efficient Navigation and Intelligent Management for Ships)

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18 pages, 3916 KiB

Open AccessArticle

Mangrove Transplantation to the North: Carbon Sequestration Capacity—Drivers and Strategies

by Kewei Zhou, Yujuan Lv, Yang Gong, Jing Su, Lei Wang, Shengmin Wu, Xi Lin, Qiuying Lai, Yixin Xu and Xingyi Duan

J. Mar. Sci. Eng. 2025, 13(8), 1577; https://doi.org/10.3390/jmse13081577 - 17 Aug 2025

Viewed by 263

Abstract

Mangroves play a pivotal role in carbon sequestration. To investigate the characteristics and driving factors of carbon sequestration in planted mangrove forests, we focused on planted mangrove forests in Wenzhou City, Zhejiang Province, China. Through a statistical analysis of soil physicochemical properties and [...] Read more.

Mangroves play a pivotal role in carbon sequestration. To investigate the characteristics and driving factors of carbon sequestration in planted mangrove forests, we focused on planted mangrove forests in Wenzhou City, Zhejiang Province, China. Through a statistical analysis of soil physicochemical properties and plant morphological characteristics, we assessed carbon stock distribution patterns and identified key influencing factors, providing scientific support for the northward expansion of mangroves. The results demonstrated significant differences in soil properties and plant morphological characteristics among different stands (p < 0.05). The mean soil carbon stock of restored planted mangroves was 78.75 Mg C/ha (mature stands: 87.84 Mg C/ha; middle-aged stands: 74.09 Mg C/ha; young stands: 74.31 Mg C/ha), while the average plant carbon stock was 12.28 Mg C/ha, indicating that soil is the primary contributor to carbon sequestration in mangroves. Compared to natural mangroves, the restored planted mangroves still exhibited a lower carbon sequestration capacity. The variations in carbon sequestration levels among the planted mangrove forests were mainly attributed to differences in tree species and age composition, hydrothermal conditions, and biomass carbon quantification methods. Key drivers of soil carbon sequestration included total phosphorus content, bulk density, and clay content. Carbon storage in restored planted mangroves depends on short-term soil carbon accumulation and long-term biomass carbon accumulation. Ultimately, we recommend optimal species selection and planting design, improved soil carbon storage mechanisms, and integrated conservation monitoring systems to enhance carbon sequestration in mangrove plantations. Full article

(This article belongs to the Section Coastal Engineering)

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21 pages, 1550 KiB

Open AccessArticle

Exploiting Maritime Wi-Fi: Practical Assessment of Onboard Network Vulnerabilities

by Marko Vukšić, Jasmin Ćelić, Ivan Panić and Aleksandar Cuculić

J. Mar. Sci. Eng. 2025, 13(8), 1576; https://doi.org/10.3390/jmse13081576 - 17 Aug 2025

Viewed by 353

Abstract

With the growing integration of digital technologies on modern vessels, ranging from satellite links and mobile networks to onboard Wi-Fi, the exposure of maritime systems to cyber threats has become a pressing concern. Wireless networks on ships, although essential for operations and crew [...] Read more.

With the growing integration of digital technologies on modern vessels, ranging from satellite links and mobile networks to onboard Wi-Fi, the exposure of maritime systems to cyber threats has become a pressing concern. Wireless networks on ships, although essential for operations and crew welfare, often lack sufficient protection and are frequently overlooked in broader cybersecurity strategies. This article explores vulnerabilities linked to Man-in-the-Middle attacks and rogue access points, particularly in port areas where attackers may exploit signal range and proximity. A simulation carried out in a public setting near the Port of Rijeka demonstrated how standard crew devices could be lured into connecting to a counterfeit Wi-Fi network, resulting in traffic interception and potential data leaks. Although practical limitations, such as signal attenuation and distance, reduce the feasibility of such intrusions at sea, the risk remains significant while in port. Insecure configurations and common user behaviors were identified as key enablers. The article outlines a series of countermeasures aligned with international guidelines ranging from segmentation and encryption to crew training and intrusion detection. Addressing these wireless vulnerabilities is essential for building resilience and ensuring that digital transformation efforts in the maritime sector do not come at the expense of security. Full article

(This article belongs to the Section Ocean Engineering)

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23 pages, 5336 KiB

Open AccessArticle

Hydrochemistry of Blackwaters in a Shoreline Zone of São Paulo State, Brazil

by Daniel M. Bonotto, Marina Lunardi and Ashantha Goonetilleke

J. Mar. Sci. Eng. 2025, 13(8), 1575; https://doi.org/10.3390/jmse13081575 - 16 Aug 2025

Viewed by 341

Abstract

Blackwater rivers are enriched in humic acids and impoverished in nutrients, sometimes discharging into oceans. Brazil has a coastal zone of about 8700 km, with several blackwater rivers discharging into the Atlantic Ocean, in addition to the Rio Negro of the northern Amazon [...] Read more.

Blackwater rivers are enriched in humic acids and impoverished in nutrients, sometimes discharging into oceans. Brazil has a coastal zone of about 8700 km, with several blackwater rivers discharging into the Atlantic Ocean, in addition to the Rio Negro of the northern Amazon basin, which is the largest (about 1700 km long) and best-known tropical backwater river. On the other hand, only a few attempts have been made to deal with their hydrochemical composition and how it is related to the hydrochemistry of different water bodies nearby. This paper focuses on a sector of the Atlantic Ocean shore occurring in São Paulo State, enclosing two important Ecological Reserves, i.e., the Restinga State Park of Bertioga and the State Park of Serra do Mar–São Sebastião Nucleus, located at Bertioga and São Sebastião cities, respectively. Physicochemical parameters such as pH and electrical conductivity, as well as the composition of major constituents like sodium, potassium, calcium, magnesium, bicarbonate, chloride, sulfate, nitrate, etc., have been evaluated in two blackwater rivers and one blackwater stream to compare their relative inputs into the Atlantic Ocean. Traditional hydrogeochemical diagrams such as the Piper, Schoeller, Gibbs, van Wirdum, and Wilcox graphs were utilized for investigating the major features of the blackwater’s composition, revealing in some cases that they suffer an accentuated influence of the constituents occurring in the Atlantic Ocean waters, due to backward currents (coastal upwelling or tidal currents). Another highlight of this paper is the measurement of an enhanced concentration of dissolved iron in one blackwater sample analyzed, reaching a value of 1.9 mg/L. Such a finding has also been often reported in the literature for blackwater rivers and streams, as humic and fulvic acids are used to bind Fe³⁺, keeping it in solution. Nowadays, iron in solution has been considered a very important element acting as a natural fertilizer of the coastal ocean because it is an essential nutrient to marine phytoplankton. Full article

(This article belongs to the Section Chemical Oceanography)

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16 pages, 3685 KiB

Open AccessArticle

Chasing Ghosts: Evidence-Based Management of Abandoned Fishing Gear in the Eastern Mediterranean

by Carlos Jimenez and Vasilis Resaikos

J. Mar. Sci. Eng. 2025, 13(8), 1574; https://doi.org/10.3390/jmse13081574 - 16 Aug 2025

Viewed by 618

Abstract

The environmental problem of abandoned fishing gear (e.g., ghost nets) exists on a world scale. It impacts marine biodiversity for decades after the nets has become lost in the ocean. In Cyprus (eastern Mediterranean), ghost nets are found almost everywhere around the island, [...] Read more.

The environmental problem of abandoned fishing gear (e.g., ghost nets) exists on a world scale. It impacts marine biodiversity for decades after the nets has become lost in the ocean. In Cyprus (eastern Mediterranean), ghost nets are found almost everywhere around the island, threatening marine life and human activities, such as scuba diving, fishing and navigation. To achieve meaningful outcomes for biodiversity conservation and the management of an offshore site that is particularly affected by ghost nets, the Jubilee Shoals, this issue is addressed in this study with an evidence-based approach. Pre-removal surveys were necessary to assess the nets and produce the environmental, ecological and structural data for the calculation of the Gear Removal Index (GRI). The results of a revised version of the index (GRI+) that includes species of conservation interest and invasive species were cross-checked in the field by divers with experience in marine ecology and similar removals. About 3 km of nets in total were successfully removed. The implementation of the GRI+ was an important proof-of-concept for environmental managers, aiding them to decide whether it would be necessary (or not) to perform removals and highlighting the index as a useful tool for the protection and management of Cyprus’ marine habitats. Full article

(This article belongs to the Section Marine Environmental Science)

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21 pages, 8582 KiB

Open AccessArticle

Study on the Influence of Fluid Fields on the Impact Force of Ships Colliding with Bridges

by Enshi Jia, Yuheng Chen, Shuxia Ren, Mingcai Xu, Jin Pan and Hai Fang

J. Mar. Sci. Eng. 2025, 13(8), 1573; https://doi.org/10.3390/jmse13081573 - 16 Aug 2025

Viewed by 212

Abstract

This study employs a fluid–structure interaction (FSI) collision-modeling approach to investigate the hydrodynamic effects on impact forces during collisions involving ships and bridges. The influences of the collision speed, the mass of the ship, and the water-flow velocity on the impact force are [...] Read more.

This study employs a fluid–structure interaction (FSI) collision-modeling approach to investigate the hydrodynamic effects on impact forces during collisions involving ships and bridges. The influences of the collision speed, the mass of the ship, and the water-flow velocity on the impact force are investigated. The constant added-mass (CAM) method is a widely employed technique in relevant studies to account for water influence due to its efficiency in conserving computational resources and reducing analysis time. This method is also employed in numerical simulations for comparative analysis. The impact force and dynamical response of a container ship using the FSI and CAM methods are investigated to determine whether the CAM method is suitable for considering the influence of the water surrounding the ship. The impact forces assessed by numerical simulations are also compared with the existing formulae. It is found that the water flow significantly affects the collision force, which must be taken into account in high-energy collision situations. Full article

(This article belongs to the Section Ocean Engineering)

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25 pages, 5827 KiB

Open AccessArticle

Multi-Scale CNN for Health Monitoring of Jacket-Type Offshore Platforms with Multi-Head Attention Mechanism

by Shufeng Feng, Lei Song, Jia Zhou, Zhuoyi Yang, Yoo Sang Choo, Tengfei Sun and Shoujun Wang

J. Mar. Sci. Eng. 2025, 13(8), 1572; https://doi.org/10.3390/jmse13081572 - 16 Aug 2025

Viewed by 285

Abstract

Vibration-based structural health monitoring methods have been widely applied in the field of damage identification. This paper proposes an intelligent diagnostic approach that integrates a multi-scale convolutional neural network with a multi-head attention mechanism (MSCNN-MHA) for the structural health monitoring of jacket-type offshore [...] Read more.

Vibration-based structural health monitoring methods have been widely applied in the field of damage identification. This paper proposes an intelligent diagnostic approach that integrates a multi-scale convolutional neural network with a multi-head attention mechanism (MSCNN-MHA) for the structural health monitoring of jacket-type offshore platforms. Through numerical simulations, acceleration response signals of three-pile and four-pile jacket platforms under random wave excitation are analyzed. Damage localization studies are conducted under simulated crack and pitting corrosion cases. Unlike previous studies that often idealize damage by weakening structural parameters or removing components, this study focuses on small-scale damage forms to better reflect real engineering conditions. To verify the noise resistance of the proposed method, noise is added to the original signals for further testing. Finally, experiments are conducted on the basic structure of the jacket-type offshore platform, simulating small-scale crack and pitting damage under sinusoidal and pulse excitation, to further evaluate the applicability of the method. Compared to previous CNN and MSCNN-based approaches, the results of this study demonstrate that the MSCNN-MHA method achieves higher accuracy in identifying and locating minor damage in jacket-type offshore platforms. Full article

(This article belongs to the Section Ocean Engineering)

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19 pages, 4922 KiB

Open AccessArticle

Forecasting Ocean Mesoscale Eddies in the Northwest Pacific in a Dynamic Ocean Forecast System

by Jiakang Zhang, Hailong Liu, Mengrong Ding, Yao Meng, Weipeng Zheng, Pengfei Lin, Zipeng Yu, Yiwen Li, Pengfei Wang and Jian Chen

J. Mar. Sci. Eng. 2025, 13(8), 1571; https://doi.org/10.3390/jmse13081571 - 15 Aug 2025

Viewed by 322

Abstract

The LICOM Forecast System (LFS), a global eddy-resolving ocean forecasting system, provides 1–15-day forecasts of ocean mesoscale eddies (OMEs). This study conducts a comparative analysis of the forecast results against observational data, thereby evaluating the performance of the LFS. Results show that LFS [...] Read more.

The LICOM Forecast System (LFS), a global eddy-resolving ocean forecasting system, provides 1–15-day forecasts of ocean mesoscale eddies (OMEs). This study conducts a comparative analysis of the forecast results against observational data, thereby evaluating the performance of the LFS. Results show that LFS underestimates the number of eddies by ~10% and their amplitude by ~30%, while overestimating eddy radius by ~5% and velocity by ~25%. Forecasted eddies are matched on a one-to-one basis with observed eddies based on distance, ensuring that those forecasted eddies that can locate corresponding counterparts in the observational dataset yield accurate forecasts. The outcomes reveal that the LFS successfully forecasts 63% of the eddies in the NWP. The characteristics of these accurately forecasted eddies are delineated. The findings indicate that eddies with greater amplitudes are more likely to be accurately predicted. Additionally, we further scrutinized the correlation between eddy attributes and forecast performance, revealing that with an increase in amplitude or a decrease in velocity, the LFS produces forecasts with improved locational accuracy. The mean forecast error in eddy position is 79.94 km for a 1-day lead time, which decreases to 70.97 km for eddies with amplitudes exceeding 1 cm and velocities below 1 km/day. Full article

(This article belongs to the Section Physical Oceanography)

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35 pages, 7630 KiB

Open AccessReview

A Review of Research on Autonomous Collision Avoidance Performance Testing and an Evaluation of Intelligent Vessels

by Xingfei Cao, Zhiming Wang, Yahong Zhu, Ting Zhang, Guoyou Shi and Yingyu Shi

J. Mar. Sci. Eng. 2025, 13(8), 1570; https://doi.org/10.3390/jmse13081570 - 15 Aug 2025

Viewed by 269

Abstract

As intelligent vessel technology moves from the proof-of-concept stage to engineering applications, the performance testing and evaluation of autonomous collision avoidance algorithms have become core issues for safeguarding maritime traffic safety. The International Maritime Organization (IMO)’s Maritime Safety Committee (MSC), at its 109th [...] Read more.

As intelligent vessel technology moves from the proof-of-concept stage to engineering applications, the performance testing and evaluation of autonomous collision avoidance algorithms have become core issues for safeguarding maritime traffic safety. The International Maritime Organization (IMO)’s Maritime Safety Committee (MSC), at its 109th session, agreed to a revised road map for the development of the Maritime Autonomous Surface Ships (MASS) Code; the field has experienced the development stages of single-vessel collision avoidance validation based on COLREGs, multimodal algorithm collaborative testing, and the current construction of a progressive validation system for the integration of a mix of virtual reality and actual reality. In recent years, relevant studies have achieved research achievements, especially in the compatibility of COLREGs and in accurate collision avoidance in complex situations, and other algorithm tests and evaluations have made great breakthroughs. However, a systematic literature review is still lacking. In this paper, we systematically review the research progress of autonomous collision avoidance performance testing and the evaluation of intelligent vessels; summarize the advantages and disadvantages of virtual testing, model testing, and full-scale vessel testing; and analyze the applicability and limitations of mainstream algorithms such as the velocity obstacle algorithm, the artificial potential field algorithm, and reinforcement learning. It focuses on the key technologies such as diverse scene generation, local scene slicing, and the construction of an evaluation index system. Finally, this paper summarizes the challenges faced by autonomous collision avoidance performance testing and the assessment of intelligent vessels and proposes potential technical solutions and future development directions in terms of virtual–real fusion testing, dynamic evaluation index optimization, and multimodal algorithm co-validation, aiming to provide a reference for the further development of this field. Full article

(This article belongs to the Section Ocean Engineering)

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J. Mar. Sci. Eng., Volume 13, Issue 8 (August 2025) – 218 articles

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