Journal of Marine Science and Engineering

18 pages, 1788 KB

Open AccessArticle

Robust Relative Space Motion Control of Underwater Vehicles Using Time Delay Estimation

by Gun Rae Cho, Hyungjoo Kang, Min-Gyu Kim, Sungho Park, Chulhee Bae, Han-Sol Jin, Seongho Jin and Ji-Hong Li

J. Mar. Sci. Eng. 2025, 13(11), 2214; https://doi.org/10.3390/jmse13112214 - 20 Nov 2025

Viewed by 232

Abstract

This paper presents a robust trajectory-tracking control framework for underwater vehicles operating in a relative coordinate system. Unlike conventional methods that define trajectories in the world frame, the proposed approach formulates the control problem directly in a moving reference frame, enabling accurate motion [...] Read more.

This paper presents a robust trajectory-tracking control framework for underwater vehicles operating in a relative coordinate system. Unlike conventional methods that define trajectories in the world frame, the proposed approach formulates the control problem directly in a moving reference frame, enabling accurate motion control with respect to dynamic and drifting objects affected by environmental disturbances such as ocean currents and waves. This relative-space formulation is particularly advantageous for tasks including diver guidance, floating-object inspection, and docking, where the reference itself is nonstationary. A coordinate transformation is introduced to consistently express the vehicle dynamics in the relative frame. Based on the transformed dynamics, a Time Delay Control (TDC) law is applied to estimate unmodeled dynamics and external disturbances without requiring precise system parameters. Theoretical stability analysis shows that the stability condition of the proposed controller is consistent with that of conventional TDC, allowing similar gain-tuning procedures. Simulation results demonstrate that the proposed controller achieves robust and smooth trajectory tracking even when the reference frame undergoes motion induced by ocean currents. Full article

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

► Show Figures

Figure 1

58 pages, 15734 KB

Open AccessArticle

Study on Combustion Characteristics of Compression Ignition Marine Methanol/Diesel Dual-Fuel Engine

by Zhongcheng Wang, Jie Zhu, Xiaoyu Liu, Jingjun Zhong and Xin Jiang

J. Mar. Sci. Eng. 2025, 13(11), 2213; https://doi.org/10.3390/jmse13112213 - 20 Nov 2025

Viewed by 256

Abstract

With the increasing global demand for environmental protection and sustainable energy utilization, methanol, as a clean and renewable fuel, has become a research focus in the field of marine engines. However, its application in compression ignition engines faces bottlenecks such as low combustion [...] Read more.

With the increasing global demand for environmental protection and sustainable energy utilization, methanol, as a clean and renewable fuel, has become a research focus in the field of marine engines. However, its application in compression ignition engines faces bottlenecks such as low combustion efficiency and poor stability. Taking the L23/30H marine diesel engine as the research object, this paper establishes a combustion simulation model for a methanol/diesel dual-fuel direct-injection engine. The reliability of the model is ensured through grid independence verification and model calibration, and a coupled chemical reaction kinetic mechanism containing 126 species and 711 elementary reactions is constructed. A systematic study is conducted on the effects of injection strategies, including fuel operating modes, spray development patterns, injection intervals, and injection timing, on combustion characteristics. The results show that under the optimized injection strategy (vertical cross spray + synchronous injection) proposed in this study and operating conditions with a high methanol substitution ratio, the combustion efficiency, dynamic performance, and soot emission control effect of the dual-fuel mode are superior to those of the pure diesel mode. Simulation results show that the combined strategy of vertical cross injection and synchronous injection can significantly increase the indicated thermal efficiency (ITE) by 3.2%, reduce the brake specific fuel consumption (BSFC) by approximately 4.5%, advance the peak heat release by 2 °CA, and remarkably improve the combustion efficiency, while earlier injection timing is beneficial to air–fuel mixing. Further comparison of combustion and emission characteristics under different boundary conditions such as methanol energy ratios and injection pressures reveals that increasing methanol injection pressure, compression ratio, and initial pressure can improve combustion uniformity and reduce soot emissions, but NO_x emissions increase, which requires the coordination of after-treatment technologies. Through the comprehensive optimization of multiple parameters, efficient and clean combustion under a high methanol substitution rate is achieved. This paper provides theoretical support and practical guidance for the technological development of marine methanol dual-fuel engines. In the future, industrial applications can be promoted by combining actual engine tests and after-treatment technologies. Full article

(This article belongs to the Special Issue Advanced Technologies for New (Clean) Energy Ships—2nd Edition)

► Show Figures

Figure 1

22 pages, 1579 KB

Open AccessArticle

Integrated Sediment and Mussel Chemical Analysis for Environmental Quality Assessment in Rovinj’s Coastal Waters (Northern Adriatic, Croatia)

by Jadranka Pelikan, Kristina Grozić, Luca Privileggio, Dijana Pavičić-Hamer, Mirta Smodlaka Tanković, Kristina Pikelj, Marin Glad and Bojan Hamer

J. Mar. Sci. Eng. 2025, 13(11), 2212; https://doi.org/10.3390/jmse13112212 - 20 Nov 2025

Viewed by 346

Abstract

Marine sediments are a key component of aquatic ecosystems, linking diverse water uses, functions, and services. Chemical contamination of sediments is a global concern, with many jurisdictions striving to prevent future pollution and manage existing contamination. This study evaluates the contamination status of [...] Read more.

Marine sediments are a key component of aquatic ecosystems, linking diverse water uses, functions, and services. Chemical contamination of sediments is a global concern, with many jurisdictions striving to prevent future pollution and manage existing contamination. This study evaluates the contamination status of Rovinj’s coastal waters using an integrated approach that combines sediment and biota chemical analyses. Sediments were analyzed to assess long-term contaminant accumulation (D8.C1), while the Mediterranean mussel (Mytilus galloprovincialis) served as a bioindicator of bioavailable contaminants and their cumulative effects on marine habitats (D8.C2). Sediment samples were collected from five sites (S1–S5), and mussels were caged using Mussel Watch installations for approximately 120 days at a control site (Lim Bay) and within Rovinj harbor. Both matrices were analyzed for heavy metals (As, Cd, Cu, Cr, Hg, Ni, Pb, and Zn), polycyclic aromatic hydrocarbons (16 PAHs), and polychlorinated biphenyls (PCBs), following the EU Water Framework Directive. All sampled locations showed a reduction in sediment contamination relative to 2011 data, with most concentrations below ecotoxicological thresholds. Exceptions included elevated ΣPAH and PCB concentrations in the harbor (S1 = 3.18 mg/kg DW; 0.33 mg/kg DW) and marina (S2 = 3.64 mg/kg DW; 0.89 mg/kg DW), as well as Ni levels (S3 = 30 mg/kg DW; S4 = 34 mg/kg DW). Despite higher contaminant loads at some locations, mussel contaminant bioaccumulation remained limited, and their vitality and survival were only moderately affected in the harbor. Although localized increases in some contaminants were detected, all calculated Q_PECm values remained below 1.0, indicating no significant ecological risk. However, a moderate-to-high probability of toxic effects (P) may occur with long-term exposure for biota inhabiting harbor and marina areas. The results of this study demonstrate continued improvement in the environmental quality of Rovinj’s coastal waters compared to the previous decade. Full article

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

► Show Figures

Graphical abstract

17 pages, 5398 KB

Open AccessArticle

Life-Cycle Impacts of Artificial Islands on Shoreline Evolution: A High-Frequency Satellite-Based Assessment

by Xiaodong Zhang, Zenglei Yue, Gang Liu and Yanhui Wang

J. Mar. Sci. Eng. 2025, 13(11), 2211; https://doi.org/10.3390/jmse13112211 - 20 Nov 2025

Viewed by 288

Abstract

Offshore artificial islands are increasingly constructed along sedimentary coasts, yet their life-cycle impacts on adjacent beaches remain poorly quantified. Here we analyze 21 years of high-frequency satellite observations to assess how the building and removal of two adjacent islands (Ridao and Yuedao) altered [...] Read more.

Offshore artificial islands are increasingly constructed along sedimentary coasts, yet their life-cycle impacts on adjacent beaches remain poorly quantified. Here we analyze 21 years of high-frequency satellite observations to assess how the building and removal of two adjacent islands (Ridao and Yuedao) altered shoreline evolution at Riyue Beach, China. A total of 884 Landsat and Sentinel-2 images were processed with sub-pixel shoreline detection, georeferenced against a stable coastal highway and corrected for tidal elevation to derive mean water shoreline positions along 19 transects. Results show that island emplacement triggered rapid salient growth (62–86 m yr⁻¹) opposite the structures and temporary erosion on their flanks. A full tombolo formed on the lee side of Ridao within four years. As the salient widened, the former eroding flanks switched from an “erosional shadow” to a “secondary shelter” and began to re-accrete. The study also reveals lateral coupling between the islands; combined with previous work, it encompasses a critical D/L (offshore distance/alongshore length) threshold of 0.44–0.9 for salient–tombolo formation. Rather than perpetual dredging, we recommend accepting the impending landward connection of Ridao Island. This strategy would eliminate maintenance costs and provide a practical reference for the sustainable management of artificial island shorelines. Full article

(This article belongs to the Special Issue Big Data and Artificial Intelligence Applications to Estuarine-Coastal-Marine Environments)

► Show Figures

Figure 1

18 pages, 6916 KB

Open AccessArticle

Trajectory Tracking Control of an Autonomous Underwater Vehicle Under Disturbance and Model Uncertainty

by Libo Dai, Desheng Zhang, Songhui Wang, Guoping Nie, Xiaoyu Zhu and Xin Wang

J. Mar. Sci. Eng. 2025, 13(11), 2210; https://doi.org/10.3390/jmse13112210 - 20 Nov 2025

Viewed by 339

Abstract

This paper studies the trajectory tracking control problem of an autonomous underwater vehicle (AUV). A robust model predictive control (MPC) framework based on the implementation of the receding horizon is implemented to address the challenges of unknown external disturbances and model uncertainties faced [...] Read more.

This paper studies the trajectory tracking control problem of an autonomous underwater vehicle (AUV). A robust model predictive control (MPC) framework based on the implementation of the receding horizon is implemented to address the challenges of unknown external disturbances and model uncertainties faced by the AUV in trajectory tracking control. Within this MPC framework, a formulation that simultaneously handles both practical actuator limitations and dynamic environmental constraints is introduced. Specifically, the controller enforces hard constraints on both the maximum driving force and also the maximum rate of change in the propeller driving force. This rate constraint is essential for ensuring the control signal respects the physical dynamics of the thrusters and prevents hardware damage. These hardware-level constraints are integrated with online updates of system state constraints which define the AUV’s working space, granting it autonomous obstacle avoidance capabilities. Finally, the performance of the controller is demonstrated by simulations and physical experiment results. Full article

(This article belongs to the Special Issue Advanced Studies in Marine Mechanical and Naval Engineering)

► Show Figures

Figure 1

16 pages, 17815 KB

Open AccessArticle

Learning to Equalize for Single-Carrier Underwater Acoustic Communications

by Hao Zhao, Kexing Yao, Dan Xiang, Qisen Wang, Yankun Chen and Yan Wang

J. Mar. Sci. Eng. 2025, 13(11), 2209; https://doi.org/10.3390/jmse13112209 - 20 Nov 2025

Viewed by 283

Abstract

Learning-based equalizers for multicarrier communication systems have been widely studied over underwater acoustic (UWA) channels. In this article, a learning-based equalizer is utilized for single-carrier (SC) underwater acoustic communications. A comprehensive comparison is made between existing deep learning (DL)-based approaches and a classical [...] Read more.

Learning-based equalizers for multicarrier communication systems have been widely studied over underwater acoustic (UWA) channels. In this article, a learning-based equalizer is utilized for single-carrier (SC) underwater acoustic communications. A comprehensive comparison is made between existing deep learning (DL)-based approaches and a classical equalizer designed with adaptive filtering principles. It motivates the design of equalization for SC communications over underwater acoustic channels. To overcome distortion over the UWA channel, we propose a sliding deep learning-based equalizer that uses a sliding nonlinear network for equalization rather than a single-layer linear method. Moreover, to accelerate convergence during training, we proposed a preprocessing-based training phase. To mitigate the impact of time-varying channels, we additionally propose a meta-learning-enhanced adaptive filter algorithm for online adaptive equalization, named Meta-DNN. Based on the proposed DL equalizer, we leverage the pilot and data relationship to perform online transfer to achieve better BER performance. Moreover, to make this work more convincing, we test bit-error-rate (BER) performance across reproducible, realistic multi-scenario channels. Full article

(This article belongs to the Special Issue Development of Theories and Systems in Underwater Communications and Networks)

► Show Figures

Figure 1

20 pages, 20040 KB

Open AccessArticle

Cyclostratigraphic Analysis and Depositional Environment Evolution of the Third Member of Eocene Shahejie Formation in the Laizhou Bay Sag, Southern Bohai Bay

by Jun-E Ni, Taiju Yin, Yuqing Zhang, Peng Liu, Zhongheng Sun and Chengcheng Zhang

J. Mar. Sci. Eng. 2025, 13(11), 2208; https://doi.org/10.3390/jmse13112208 - 20 Nov 2025

Viewed by 313

Abstract

This study conducts a cyclostratigraphic analysis of the third member of the Eocene Shahejie Formation (Es3) in the Laizhou Bay Sag, Bohai Bay Basin, to investigate the influences of astronomically driven climate variations on sea-level changes, sedimentation rates, and depositional environments. We integrated [...] Read more.

This study conducts a cyclostratigraphic analysis of the third member of the Eocene Shahejie Formation (Es3) in the Laizhou Bay Sag, Bohai Bay Basin, to investigate the influences of astronomically driven climate variations on sea-level changes, sedimentation rates, and depositional environments. We integrated high-resolution geophysical well logs, ostracod fossils, and palynological data from Well B-2 for cyclostratigraphic and paleoclimate analyses. Time series analysis identified orbital cyclicity in the natural gamma-ray (GR) log, with its significance confirmed by correlation coefficients and statistical significance tests. By tuning the GR log to the 405 kyr eccentricity cycle, we constructed a ~7.695 Myr floating astronomical timescale. Integrating the preliminary biostratigraphic framework (based on ostracods and palynology) with the La2010d astronomical solution yielded a high-resolution absolute astronomical timescale for the 1317–2594 m interval of Well B-2, spanning from 33.9 to 41.6 Ma. Sedimentary noise modeling reconstructed the Eocene sea-level curve in the study area, revealing that the 1.2 Myr obliquity modulation cycle was a key driver of sea-level fluctuations. The δ¹³C and δ¹⁸O records confirm the presence of the Middle Eocene Climatic Optimum (MECO), indicating that its stratigraphic signature constitutes a robust marker for regional stratigraphic subdivision in the southern Bohai Bay Basin. Our findings provide new insights into the climatic evolution of the Es3 member in the southern Bohai Bay Basin. Full article

(This article belongs to the Section Geological Oceanography)

► Show Figures

Figure 1

17 pages, 6773 KB

Open AccessReview

Harvest Recovery of a North Atlantic Intertidal Seaweed, Ascophyllum nodosum: Experimental Design Issues

by Allison A. Snow, David Porter, David J. Garbary and Herb Vandermeulen

J. Mar. Sci. Eng. 2025, 13(11), 2207; https://doi.org/10.3390/jmse13112207 - 19 Nov 2025

Viewed by 425

Abstract

As the global demand for seaweed products increases, resource managers, conservation groups, and other stakeholders strive to protect wild seaweed populations and the ecosystem services they provide from the damaging effects of over-harvesting. Ascophyllum nodosum (rockweed) is a slow-growing, intertidal brown alga of [...] Read more.

As the global demand for seaweed products increases, resource managers, conservation groups, and other stakeholders strive to protect wild seaweed populations and the ecosystem services they provide from the damaging effects of over-harvesting. Ascophyllum nodosum (rockweed) is a slow-growing, intertidal brown alga of the North Atlantic that is commercially harvested for crop biostimulants, soil conditioners, and other products. Rockweed is considered a foundation species due to its high abundance, tall canopy, habitat characteristics, and role in detrital food webs. Rockweed shoots survive after harvesting if the holdfast remains intact, but rates of canopy and biomass recovery depend on the intensity of harvesting. In Maine, USA, and eastern Canada, little is known about how harvesting rockweed at various intensities affects recovery rates of algal height or biomass. Herein, we evaluate published studies and suggest improved experimental designs. Most experimental studies focus on a single harvest event, often with incomplete data on control plots, amount of biomass removed, or previous harvesting history at study sites. Much has been learned from previous work, but more rigorous studies are needed to develop harvest recommendations that address both commercial and conservation-related goals. Importantly, experimental studies of the effects of repeated harvesting on rockweed beds are lacking. Full article

(This article belongs to the Section Marine Biology)

► Show Figures

Figure 1

20 pages, 4482 KB

Open AccessArticle

Pore-Structure-Controlled Acoustic Characteristics for Predicting Shallow Gas Distribution in Polar Offshore Drilling

by Lei Li, Li He, Ying Zhao, Yu Song, Shiming Wei, Guojing Zhu, Qingying Tang and Tiancong Cui

J. Mar. Sci. Eng. 2025, 13(11), 2206; https://doi.org/10.3390/jmse13112206 - 19 Nov 2025

Viewed by 212

Abstract

Shallow gas drilling in polar seas poses severe geological hazards, particularly unexpected eruptions that threaten platform safety and the marine environment. Accurate prediction of shallow gas occurrence and eruption risk is therefore essential for safe deep-water operations. However, previous studies seldom considered the [...] Read more.

Shallow gas drilling in polar seas poses severe geological hazards, particularly unexpected eruptions that threaten platform safety and the marine environment. Accurate prediction of shallow gas occurrence and eruption risk is therefore essential for safe deep-water operations. However, previous studies seldom considered the coupled effects of gas pressure and pore-structure evolution on acoustic wave velocity, leading to deviations in hazard assessment. In this study, laboratory experiments and numerical simulations were conducted to clarify these mechanisms. Results revealed a non-monotonic relationship between porosity and P-wave velocity in shallow gas-bearing sediments: P-wave velocity decreases with increasing porosity at low porosity levels but increases beyond a critical threshold. This is attributed to changes in particle interactions and cementation that enhance the shear modulus. The inflection porosity for shallow gas (78%) highlights the diagnostic role of pore-structure evolution in predicting shallow gas distribution. A mathematical correlation between P-wave velocity and formation pressure was further established, and MP-PIC simulations showed that higher pressure coefficients significantly accelerate eruption rates, with a 0.1 increase in the pressure coefficient raising the instantaneous eruption velocity by 5.27 m³/min. Based on these findings, a quantitative evaluation method was developed to assess shallow gas hazard risk, providing engineering guidance for site selection and real-time risk prediction, and contributing to safer offshore drilling and ecological protection in polar environments. Full article

(This article belongs to the Section Geological Oceanography)

► Show Figures

Figure 1

21 pages, 34323 KB

Open AccessArticle

Ship-RT-DETR: An Improved Model for Ship Plate Detection and Identification

by Chang Qin, Xiaoyu Ji, Zhiyi Mo and Jinming Mo

J. Mar. Sci. Eng. 2025, 13(11), 2205; https://doi.org/10.3390/jmse13112205 - 19 Nov 2025

Viewed by 227

Abstract

Ship License Plate Recognition (SLPR) technology serves as a fundamental technological foundation for maritime transportation management. Automated ship identification enhances both regulatory oversight and operational efficiency. However, current recognition models demonstrate significant limitations, including their inability to detect objects in complex environments and [...] Read more.

Ship License Plate Recognition (SLPR) technology serves as a fundamental technological foundation for maritime transportation management. Automated ship identification enhances both regulatory oversight and operational efficiency. However, current recognition models demonstrate significant limitations, including their inability to detect objects in complex environments and challenges in maintaining real-time performance while ensuring accuracy, thereby limiting their practical applicability. This study proposes a novel cascaded framework that integrates RT-DETR-based detection with OCR capabilities. The framework incorporates several key methodological innovations: optimizing the RT-DETR backbone through efficient partial convolutions during training to improve computational efficiency; implementing Conv3XC to modify the ResNet18-backbone BasicBlock using a triple convolutional layer configuration with an enhanced RepC3 kernel design for better feature extraction; and integrating learned position encoding (LPE) to improve the AIFI position encoding mechanism, thereby enhancing detection capabilities. After region detection, PP-OCRv3 is used for character recognition. Experimental results demonstrate the superior performance of our approach: Ship-RT-DETR achieves 96.2% detection accuracy with a 28.5% reduction in parameters and 67.3 FPS, while PP-OCRv3 achieves 91.6% recognition accuracy. Extensive environmental validation across diverse weather conditions (sunny, cloudy, rainy, and foggy) confirms the framework’s robustness, maintaining a detection accuracy above 90% even in challenging foggy conditions, with minimal performance degradation (a 7.7% decrease from optimal conditions). The system’s consistent performance across various environmental conditions (detection standard deviation: 2.84%, OCR confidence standard deviation: 0.0295) establishes a novel and robust methodology for practical SLPR applications. Full article

(This article belongs to the Section Ocean Engineering)

► Show Figures

Figure 1

19 pages, 3953 KB

Open AccessArticle

Intelligent Diagnosis of Ship Propulsion Motor Bearings Based on Dynamic Class Weights

by Guohua Yan, Xiaoding Wang, Kai Liu, Jingran Kang and Xinhua Yi

J. Mar. Sci. Eng. 2025, 13(11), 2204; https://doi.org/10.3390/jmse13112204 - 19 Nov 2025

Viewed by 226

Abstract

As an important part of the ship’s power system, the bearing operation status of the propulsion motor is directly related to the reliability and safety of the whole system. However, in the field of marine propulsion motor bearing fault diagnosis, the data imbalance [...] Read more.

As an important part of the ship’s power system, the bearing operation status of the propulsion motor is directly related to the reliability and safety of the whole system. However, in the field of marine propulsion motor bearing fault diagnosis, the data imbalance problem seriously affects the performance of the fault detection model. Due to the scarcity of fault data relative to normal operation data, traditional diagnostic methods are ineffective in dealing with unbalanced data. To solve this problem, a dynamic class weighting solution is proposed. The dynamic class weighting method introduces the weight coefficient λ on the basis of the traditional class weighting, which can adjust the class weight value in real time according to the training situation, and comprehensively considers the data distribution and the training situation to ensure that the model can learn better even in the case of insufficient data. Testing on the imbalanced distribution of bearing natural-failure data shows that the proposed method achieves a 5.25% improvement in diagnostic accuracy compared to direct training. Compared with traditional class-weighted approaches, diagnostic accuracy is enhanced by 3.56%, effectively mitigating the impact of scarce and unevenly distributed failure data on model training. Full article

(This article belongs to the Special Issue Advances in Marine Electric Propulsion: Technologies, Systems Integration and Sustainable Maritime Transportation)

► Show Figures

Figure 1

23 pages, 1687 KB

Open AccessArticle

A Conceptual Pre-Standardization Framework for the Land-Based Test and Evaluation of Liquid Hydrogen Fuel Tank and Supply Systems

by Hyojeong Kim and Wook Kwon

J. Mar. Sci. Eng. 2025, 13(11), 2203; https://doi.org/10.3390/jmse13112203 - 19 Nov 2025

Viewed by 306

Abstract

In response to the International Maritime Organization (IMO)’s greenhouse gas reduction targets and the growing demand for decarbonization in the maritime sector, the development of hydrogen-fueled ship technologies has gained increasing attention. Liquid hydrogen (LH₂) is regarded as a promising marine [...] Read more.

In response to the International Maritime Organization (IMO)’s greenhouse gas reduction targets and the growing demand for decarbonization in the maritime sector, the development of hydrogen-fueled ship technologies has gained increasing attention. Liquid hydrogen (LH₂) is regarded as a promising marine fuel due to its high energy density per unit volume when liquefied at −253 °C, enabling large-scale storage and transportation. However, critical technical challenges remain in cryogenic storage, transfer, vaporization processes, and safety assurance. This study proposes a conceptual pre-standardization framework for land-based evaluation of LH₂ fuel tank and supply systems, supported by preliminary validation using LN₂ surrogate tests. The protocol is established through a reinterpretation of existing international and domestic standards (KGS AC111, ISO/TR 15916, CGA H-3) and adapted to Korean demonstration environments. Test items were categorized into (i) supply performance (flow and pressure), (ii) vaporization and heating performance (temperature), and (iii) safety functions, with acceptance criteria benchmarked against international guidelines. To overcome the significant safety and cost constraints of handling actual LH₂, liquid nitrogen (LN₂) was applied as a surrogate medium to enable preliminary validation under safe and practical conditions, and process simulations are proposed as a future pathway for comprehensive verification. The results highlight not only the application but also the localization and refinement of global standards into a practical protocol for small- to medium-sized ship applications. This protocol is expected to serve as a critical reference for subsequent sea trials and commercialization, thereby contributing to the advancement of eco-friendly marine fuel technologies and strengthening international competitiveness in the hydrogen powered shipping sector. Full article

(This article belongs to the Special Issue Challenges of Marine Energy Development and Facilities Engineering)

► Show Figures

Figure 1

28 pages, 3059 KB

Open AccessReview

From Machinery to Biology: A Review on Mapless Autonomous Underwater Navigation

by Wenxi Zhu and Weicheng Cui

J. Mar. Sci. Eng. 2025, 13(11), 2202; https://doi.org/10.3390/jmse13112202 - 19 Nov 2025

Viewed by 600

Abstract

Autonomous navigation in unknown; map-free environments is a core requirement for advanced robotics. While significant breakthroughs have been achieved in terrestrial scenarios, extending this capability to the unstructured, dynamic, and harsh underwater domain remains an enormous challenge. This review comprehensively analyzes the mainstream [...] Read more.

Autonomous navigation in unknown; map-free environments is a core requirement for advanced robotics. While significant breakthroughs have been achieved in terrestrial scenarios, extending this capability to the unstructured, dynamic, and harsh underwater domain remains an enormous challenge. This review comprehensively analyzes the mainstream technologies underpinning mapless autonomous underwater navigation, with a primary focus on conventional Autonomous Underwater Vehicles (AUVs). It systematically examines key technical pillars of AUV navigation, including Dead Reckoning and Simultaneous Localization and Mapping (SLAM). Furthermore, inspired by the emerging concept of fourth-generation submersibles—which leverage living organisms rather than conventional machinery—this review expands its scope to include live fish as potential controlled platforms for underwater navigation. It first dissects the sophisticated sensory systems and hierarchical navigational strategies that enable aquatic animals to thrive in complex underwater habitats. Subsequently, it categorizes and evaluates state-of-the-art methods for controlling live fish via Brain-Computer Interfaces (BCIs), proposing a three-stage control hierarchy: Direct Motor Control, Semi-Autonomous Control with Task-Level Commands, and Autonomous Control by Biological Intelligence. Finally, the review summarizes current limitations in both conventional AUV technologies and bio-hybrid systems and outlines future directions, such as integrating external sensors with fish, developing onboard AI for adaptive control, and constructing bio-hybrid swarms. This work bridges the gap between robotic engineering and biological inspiration, providing a holistic reference for advancing mapless autonomous underwater navigation. Full article

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

► Show Figures

Figure 1

17 pages, 6899 KB

Open AccessArticle

MASS-LSVD: A Large-Scale First-View Dataset for Marine Vessel Detection

by Yunsheng Fan, Dongjie Ju, Bing Han, Feng Sun, Liran Shen, Zongjiang Gao, Dongdong Mu and Longhui Niu

J. Mar. Sci. Eng. 2025, 13(11), 2201; https://doi.org/10.3390/jmse13112201 - 19 Nov 2025

Viewed by 474

Abstract

In this paper, we release a new large-scale dataset containing multiple categories of ships and floating objects at sea, which we call MASS-LSVD. It is used to train and validate target detection algorithms and future large models for ship autopiloting. The dataset was [...] Read more.

In this paper, we release a new large-scale dataset containing multiple categories of ships and floating objects at sea, which we call MASS-LSVD. It is used to train and validate target detection algorithms and future large models for ship autopiloting. The dataset was captured by a visible light camera installed aboard the world’s first intelligent research, teaching, and training ship, “Xinhongzhuan”. This MASS (maritime autonomous surface ship) was operated by Dalian Maritime University, China. We have collected more than 4000 h of video of the “Xinhongzhuan” vessel’s voyage in the Bohai Sea and other areas, which are carefully classified and filtered to cover as much as possible the various types of sample data in the marine environment, such as light intensity, weather, hull shading, data from ocean-going voyages, entering and exiting ports, etc. The dataset contains 64,263 1K-resolution images captured from video footage, covering four main ship types: Fishing Boat, Bulk Carrier, Cruise Ship, Container ship, and an ‘Other Ships’ class, for vessels that cannot be specifically classified. The dataset currently contains 64,263 pairs of 1K-resolution images covering four common ship types (fishing boat, bulk carrier, cruise ship, container, and other ship, where no specific ship type can be determined). All the images have been labeled with high-precision manual bounding boxes. In this paper, the MASS-LSVD dataset is used as the basis for training various target detection algorithms and comparing them with other datasets, which compensates for the lack of first-view images in the vessel target detection dataset, and MASS-LSVD is expected to be used to facilitate the research and application of autonomous ship navigation models in the framework of computer vision. Full article

(This article belongs to the Section Ocean Engineering)

► Show Figures

Figure 1

21 pages, 4090 KB

Open AccessArticle

A Method for Super-Resolution Reconstruction of Marine Geomagnetic Anomaly Reference Maps Based on an Improved Generative Adversarial Network

by Linglong Xia, Fangjun Qin, Wei Xu, Kailong Li, Tiangao Zhu and Yu Han

J. Mar. Sci. Eng. 2025, 13(11), 2200; https://doi.org/10.3390/jmse13112200 - 19 Nov 2025

Viewed by 281

Abstract

High-resolution marine geomagnetic anomaly maps are a prerequisite for accurate geomagnetic matching navigation. However, existing compilations are sparse and of low resolution, and conventional interpolation techniques fail to capture fine-scale anomalies. Although deep learning models have achieved remarkable success in natural-image super-resolution, they [...] Read more.

High-resolution marine geomagnetic anomaly maps are a prerequisite for accurate geomagnetic matching navigation. However, existing compilations are sparse and of low resolution, and conventional interpolation techniques fail to capture fine-scale anomalies. Although deep learning models have achieved remarkable success in natural-image super-resolution, they have rarely been tailored to geomagnetic grid data; their lack of physically motivated constraints frequently introduces geologically implausible structures. To address these limitations, we propose a physics-constrained generative adversarial network (PC-GAN) for the super-resolution reconstruction of marine geomagnetic anomaly maps. Building upon the Super-Resolution Generative Adversarial Network (SRGAN) backbone, we incorporate physics-informed loss terms for spatial continuity and edge preservation into the training objective, thereby endowing the data-driven architecture with geological consistency while maintaining numerical accuracy. Experiments were conducted on the NOAA EMAG2_V3 dataset across four representative marine regions. Over the Philippine Sea Plate, PC-GAN reduces the root-mean-square error (RMSE) by 28.0% and increases the peak signal-to-noise ratio (PSNR) by 2.85 dB relative to bicubic interpolation, and lowers RMSE by 27.5% while raising PSNR by 2.79 dB compared with PSO-Kriging. Ablation studies corroborate that the physics-based modules make a statistically significant contribution to reconstruction quality. PC-GAN furnishes a robust tool for generating high-fidelity geomagnetic reference maps and holds promise for high-precision geomagnetic matching navigation and related applications. Full article

(This article belongs to the Section Physical Oceanography)

► Show Figures

Figure 1

26 pages, 9187 KB

Open AccessArticle

Spatio-Temporal Characteristics of Ship Carbon Emissions in Port of New York and New Jersey Based on AIS Data

by Weixiong Lin, Nini Wang and Jianchuan Yin

J. Mar. Sci. Eng. 2025, 13(11), 2199; https://doi.org/10.3390/jmse13112199 - 19 Nov 2025

Viewed by 462

Abstract

Shipping is a major source of carbon emissions and faces an urgent need for decarbonization. Research on vessel carbon emissions not only characterizes regional emission patterns but also provides critical evidence for targeted mitigation policies and optimized maritime management. This study quantifies vessel [...] Read more.

Shipping is a major source of carbon emissions and faces an urgent need for decarbonization. Research on vessel carbon emissions not only characterizes regional emission patterns but also provides critical evidence for targeted mitigation policies and optimized maritime management. This study quantifies vessel carbon emissions in the Port of New York and New Jersey from February to November 2023 using Automatic Identification System (AIS) data combined with the STEAM model. An activity-weighted spatial allocation method was applied to distribute emissions across 100 m × 100 m grids. Emission characteristics were analyzed across four dimensions: vessel type, operational state, temporal variation, and spatial distribution. Results show that total emissions during the study period reached approximately 136,701.8 t, with container ships contributing 62.3% of the total. Berthing operations were identified as the dominant emission source, accounting for 73.4% of total emissions, followed by tugboats and cargo vessels. Temporally, emissions peaked in October (10.8%) and were lowest in February (8.8%), reflecting variations in trade intensity and seasonal weather conditions. Spatially, emissions exhibited strong clustering around terminal berths. A sensitivity analysis was performed to assess the robustness of the emission estimates. When the load factor (LF) varied by ±10%, total emissions changed by only ±1.85%, indicating that the results are highly stable and robust. This limited variation arises from the dominance of berthing operations with relatively steady auxiliary loads and the application of the constraint LF ≤ 1, which prevents unrealistic overloading. These findings offer indicative insights that can inform port-level emission management and serve as a reference for future low-carbon policy development. Full article

(This article belongs to the Section Ocean Engineering)

► Show Figures

Figure 1

14 pages, 2720 KB

Open AccessArticle

Upgrade and Application of the Dynamic Positioning System for a Small Waterplane Area Twin Hull Vessel

by Jinling Ying, Huabin Mao, Zhiyuan Wei, Yongfeng Qi, Biqing Wu, Chuyin Xuan, Linghui Yu, Ze Qi, Xingyue Wang, Xianpeng Li and Kajia Wu

J. Mar. Sci. Eng. 2025, 13(11), 2198; https://doi.org/10.3390/jmse13112198 - 19 Nov 2025

Viewed by 337

Abstract

The small waterplane area twin hull (SWATH) is a type of high-performance vessel known for its excellent seakeeping performance, remarkable maneuverability, and high lateral stability. These advantages have led to its growing application in scientific research ships. Since many research operations require a [...] Read more.

The small waterplane area twin hull (SWATH) is a type of high-performance vessel known for its excellent seakeeping performance, remarkable maneuverability, and high lateral stability. These advantages have led to its growing application in scientific research ships. Since many research operations require a vessel to maintain a fixed position, Dynamic Positioning Systems (DPSs) are essential. To better support diverse scientific tasks, the R/V SHIYAN 1 was upgraded with an enhanced dynamic positioning system. A ship motion model was established after comprehensively accounting for environmental factors such as wind, waves, and currents. By automatically controlling three actuators, the system successfully achieved effective dynamic positioning. In comparative tests conducted under conditions of wind speed at 13.4 m/s, wave height at 3.2 m, and current at 0.2 m/s, the power system was able to maintain a positioning radius within 5 m. Analysis of data from three dynamic positioning experiments revealed that wave loads had the most significant impact on positioning accuracy, followed by wind loads, while ocean current loads had the least influence. This upgrade not only improves the vessel’s operational capability but also enhances its effectiveness in marine scientific exploration. Full article

(This article belongs to the Section Ocean Engineering)

► Show Figures

Figure 1

22 pages, 978 KB

Open AccessArticle

An IPSO-RC-Based Study on Dynamic Coordination Excitation and Optimal Capacity Allocation for Marine Hybrid Energy Systems

by Huanbo Liu, Yi Guo, Yayu Yang and Bing Han

J. Mar. Sci. Eng. 2025, 13(11), 2197; https://doi.org/10.3390/jmse13112197 - 19 Nov 2025

Viewed by 308

Abstract

As a pivotal element in the maritime sector’s green transition, fuel-cell-powered ships have attracted increasing attention due to the energy efficiency and stability of their onboard powertrains. Yet, the dynamic coordination and capacity optimization of fuel cells and supercapacitors remain among the most [...] Read more.

As a pivotal element in the maritime sector’s green transition, fuel-cell-powered ships have attracted increasing attention due to the energy efficiency and stability of their onboard powertrains. Yet, the dynamic coordination and capacity optimization of fuel cells and supercapacitors remain among the most formidable technological challenges. In this study, a hybrid marine power system pairing fuel cells with supercapacitors is devised by integrating robust control with a particle swarm optimization (PSO) algorithm. The results reveal that, under complex operating conditions, robust control effectively mitigates system uncertainties and secures reliable operation of the ship’s energy system. Optimally allocating component capacities via PSO markedly enhances the synergy between the fuel cell and the supercapacitor. Compared with conventional schemes, optimized architecture boosts energy efficiency by 12.5%, shortens response time by 8.4%, and demonstrates clear superiority in robustness and stability. This robust-control-based hybrid configuration therefore delivers outstanding performance and offers compelling guidance for the refined design of marine propulsion systems. Full article

(This article belongs to the Special Issue Marine Fuel Cell Technology: Latest Advances and Prospects)

► Show Figures

Figure 1

23 pages, 3562 KB

Open AccessArticle

Evaluation of Different AI-Based Wave Phase-Resolved Prediction Methods

by Shunli Cao, Dezheng Yang, Hangyu Chen, Xuewen Ma and Mao Li

J. Mar. Sci. Eng. 2025, 13(11), 2196; https://doi.org/10.3390/jmse13112196 - 18 Nov 2025

Viewed by 358

Abstract

Ensuring the safe operation of marine structures requires accurate phase-resolved wave prediction. However, current studies mostly focus on single-model verification and lack a systematic comparison of mainstream architectures under multiple environmental factors on a unified experimental benchmark, thus offering limited guidance for engineering [...] Read more.

Ensuring the safe operation of marine structures requires accurate phase-resolved wave prediction. However, current studies mostly focus on single-model verification and lack a systematic comparison of mainstream architectures under multiple environmental factors on a unified experimental benchmark, thus offering limited guidance for engineering practice. To fill this gap, we conducted a systematic wave-tank evaluation that quantifies how sea state levels, directional spectrum, prediction distance and lead time jointly affect model accuracy. Four architectures—RNN, LSTM, GRU, and TCN—were trained on 7 × 7 probe matrices acquired under sea states levels (4–7), two directional spreading coefficients (n = 2 and 6), five prediction distances (6.7–33.3 m), and lead times of 1–30Δt. Root-mean-square error (RMSE) served as the quantitative metric. Among recurrent architectures, RNN-WP achieved the lowest high-frequency error under mild sea states (SS4, RMSE = 0.28 m), LSTM-WP delivered the best overall accuracy (SS4–5, RMSE ≤ 0.37 m), and GRU-WP excelled in the medium to high frequency band (SS4–5, RMSE ≤ 0.31 m), whereas TCN-WP remained most robust at long horizons and severe sea states (SS7, RMSE = 0.42 m). Increasing sea-state severity raised RMSE by 40–90%, while a narrower directional distribution amplified errors under extreme conditions. Prediction distance and lead time altered model ranking, confirming that nonlinearity, directional spreading, distance and temporal horizon are the dominant controlling factors for deep learning phase resolved wave prediction. Full article

(This article belongs to the Special Issue Artificial Intelligence and Its Applications in Intelligent Ship Navigation)

► Show Figures

Figure 1

25 pages, 27520 KB

Open AccessArticle

RAFS-Net: A Robust Adversarial Fusion Framework for Enhanced Maritime Surveillance in Hostile Environments

by Jiawen Li, Jiahua Sun, Qiqi Shi and Molin Sun

J. Mar. Sci. Eng. 2025, 13(11), 2195; https://doi.org/10.3390/jmse13112195 - 18 Nov 2025

Viewed by 268

Abstract

Deep learning-based intelligent ship surveillance technology has become an indispensable component of modern maritime intelligent perception, with its adversarial defense capabilities serving as a crucial guarantee for reliable and stable monitoring. However, current research on deep learning-based ship surveillance primarily focuses on minimizing [...] Read more.

Deep learning-based intelligent ship surveillance technology has become an indispensable component of modern maritime intelligent perception, with its adversarial defense capabilities serving as a crucial guarantee for reliable and stable monitoring. However, current research on deep learning-based ship surveillance primarily focuses on minimizing the discrepancy between predicted labels and ground truth labels, overlooking the equal importance of enhancing defense capabilities in the adversarial technology-laden maritime environment. To address this challenge and improve model robustness and stability, this study proposes a novel framework termed the Robust Adversarial Fusion Surveillance Net Framework (RAFS-Net). Utilizing ResNet as the backbone network foundation, the framework constructs a ship adversarial attack chain through an adversarial generation module. An adversarial training module enables the model to comprehensively learn adversarial perturbation features. These dual modules effectively rectify abnormal decision boundaries via a synergistic mechanism, compelling the model to learn robust feature representations resilient to malicious interference. Experimental results demonstrate that the framework maintains stable and efficient detection capabilities even in marine environments saturated with interfering information. By systematically integrating gradient-driven adversarial sample generation and an end-to-end training mechanism, it achieves a performance breakthrough of 9.1% in mean Average Precision (mAP) on the ship adversarial benchmark dataset, providing technical support for maritime surveillance models in complex adversarial environments. Full article

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

► Show Figures

Figure 1

24 pages, 2890 KB

Open AccessArticle

Spatial and Temporal Variation in Wave Overtopping Across a Coastal Structure Based on One Year of Field Observations

by Jennifer Brown, Gerd Masselink, Margaret Yelland, Christopher Stokes, Timothy Poate, Robin Pascal, David Jones, John Walk, Christopher Cardwell, Barry Martin, Peter Ganderton, Julie Gregory, Ruth Adams and Joseff Saunders

J. Mar. Sci. Eng. 2025, 13(11), 2194; https://doi.org/10.3390/jmse13112194 - 18 Nov 2025

Viewed by 450

Abstract

Coastal managers worldwide must prepare for changes in annual wave overtopping events due to climate change and sea-level rise. Research often assesses overtopping discharges by extreme events at a sea wall crest, typically using data from physical models or empirical rules based on [...] Read more.

Coastal managers worldwide must prepare for changes in annual wave overtopping events due to climate change and sea-level rise. Research often assesses overtopping discharges by extreme events at a sea wall crest, typically using data from physical models or empirical rules based on scaled experiments. Here, we analyse a unique 1-year field dataset of coastal wave overtopping, from SW England, to determine the number of individual waves, regardless of their size, overtopping two locations across a coastal structure. The coastal conditions causing the most frequent overtopping differ from those driving it landward, complicating hazard communications for multiuse infrastructure. These data are the first field observations covering a year of tide, wave and wind conditions that cause overtopping of a vertical sea wall. Storms have a minimal (<2%) contribution to the number of tides associated with overtopping and the prevailing wave direction was not that associated with most overtopping events. Overtopping histograms identify the variability in the most likely time of overtopping relative to high tide for different wave categories across the structure. Sea-level rise, beach lowering and climate change will influence the annual number of waves overtopping in future. Change will be a complex balance between overtopping by different wave categories due to their likelihood of coincidence with water levels that do not cause depth-limitation over the foreshore or (partial-)reflection off the structure. It is possible the number of waves overtopping will reduce at the crest of a sea wall, while more of those overtopping waves will travel further inland. Full article

(This article belongs to the Section Coastal Engineering)

► Show Figures

17 pages, 4977 KB

Open AccessArticle

Long-Term Trends, Interannual Variability and Seasonal Patterns of Mean Sea Level in the Canary Islands

by Mikel Ibeas and Antonio Martínez-Marrero

J. Mar. Sci. Eng. 2025, 13(11), 2193; https://doi.org/10.3390/jmse13112193 - 18 Nov 2025

Viewed by 299

Abstract

This study analyzes mean sea level variability in the Canary Islands from 1993 to 2022 using tide gauge and satellite altimetry data. During this period, both Las Palmas de Gran Canaria and Santa Cruz de Tenerife exhibited a significant sea level rise of [...] Read more.

This study analyzes mean sea level variability in the Canary Islands from 1993 to 2022 using tide gauge and satellite altimetry data. During this period, both Las Palmas de Gran Canaria and Santa Cruz de Tenerife exhibited a significant sea level rise of 4.04 ± 0.83 and 4.38 ± 0.93 mm yr⁻¹, respectively. Comparison between tide gauge and altimetry records reveals slight land subsidence at both locations, approximately 0.5–0.7 ± 0.55 mm yr⁻¹, contributing to the observed relative sea level rise. The spatial differences in the trends observed from altimetry appear to be associated with mesoscale ocean dynamics, particularly an increase in eddy activity along the Canary Eddy Corridor. Projections based on IPCC SSP scenarios suggest that sea level could rise by up to 395 mm in Santa Cruz and 365 mm in Las Palmas by 2050 under high-emission conditions. An additional 20 mm could be added due to land subsidence if it remains constant. Interannual variability is primarily correlated with the North Atlantic Oscillation (NAO); however, Atlantic Multidecadal Oscillation (AMO) and the Atlantic Meridional Overturning Circulation (AMOC) indices also appear to correlate well with its low-frequency components. The seasonal cycle, driven primarily by steric effects, peaks in late summer and reaches a minimum in late winter, with its amplitude varying across the region. The seasonal amplitude is approximately 49.6 mm in Las Palmas and 70.2 mm in Santa Cruz. Full article

► Show Figures

Figure 1

16 pages, 4463 KB

Open AccessArticle

Anatomy of Coherent Vortical Structures in Droplet-Laden Turbulent Airflow over a Wavy Water Surface

by Guan-Hung Lu, Wu-Ting Tsai and Oleg A. Druzhinin

J. Mar. Sci. Eng. 2025, 13(11), 2192; https://doi.org/10.3390/jmse13112192 - 18 Nov 2025

Viewed by 196

Abstract

This study investigates the effects of spume droplets on coherent vortical structures (CVSs) in turbulent airflow over a wavy water surface, focusing on the role of wave steepness and droplet injection velocity in modulating these interactions. Direct numerical simulations are performed using a [...] Read more.

This study investigates the effects of spume droplets on coherent vortical structures (CVSs) in turbulent airflow over a wavy water surface, focusing on the role of wave steepness and droplet injection velocity in modulating these interactions. Direct numerical simulations are performed using a droplet-laden Couette turbulent airflow over progressive surface waves as an idealized model. A Eulerian-Lagrangian approach is employed, considering low- and high-steepness wave conditions (

a k = 0.1

and

0.2

, where

a

is wave amplitude and

k

is wavenumber) and two droplet injection velocities (surface and airflow velocities near wave crest). Results from droplet-free simulations reveal strong phase dependence in CVS formation, with forward and reversed horseshoe vortices near wave troughs and quasi-streamwise vortices aligning along the windward surface. Droplets injected at the surface velocity remain near wave crests, where CVS formation is weak, leading to minimal interaction. In contrast, droplets injected at the airflow velocity disperse broadly, increasing the likelihood of interactions with CVSs. For low-steepness waves, these droplets stay within the surface layer, attenuating CVSs and suppressing ejection and sweep events. However, as wave steepness increases, more droplets escape the near-surface layer, reducing their influence on CVSs. Full article

(This article belongs to the Section Physical Oceanography)

► Show Figures

Figure 1

22 pages, 3659 KB

Open AccessArticle

Identification of Ocean Thermal Energy Conversion Heat Exchange Model Based on Long Short-Term Memory Network and Heat Exchange Efficiency Improvement Study

by Yanjun Liu, Xiu You, Mingqian Tian, Tianxu Zhang, Yun Chen and Yanni Yu

J. Mar. Sci. Eng. 2025, 13(11), 2191; https://doi.org/10.3390/jmse13112191 - 18 Nov 2025

Viewed by 245

Abstract

The core of ocean thermal energy conversion (OTEC) is the transfer and conversion of heat energy, and the heat exchanger is a key component of the heat transfer between the surface warm seawater and the lower cold seawater. The working fluid has a [...] Read more.

The core of ocean thermal energy conversion (OTEC) is the transfer and conversion of heat energy, and the heat exchanger is a key component of the heat transfer between the surface warm seawater and the lower cold seawater. The working fluid has a significant impact on the efficiency of the entire cycle in the temperature difference cycle. This study aimed to improve heat exchange efficiency. The article studied heat exchangers, used R134a as the circulating medium, and applied ANSYS-FLUENT 2020R2 simulation software to analyze the variation in heat transfer coefficients. We obtained the trend in the heat transfer coefficient of the heat exchanger with the shape of an elliptical tube under the condition of ocean temperature difference cycles. Then we used a long short-term memory network and Adam optimization algorithm to establish the prediction model. The NSGA-II 11 algorithm was used to realize optimization objectives of the highest heat transfer efficiency and the smallest cross-sectional area of heat transfer tubes along the X and Y directions. Finally, the parameters of the evaporator and condenser ultimately resulted in three optimal solutions. The results of this study can provide a certain theoretical basis and reference value for the efficiency analysis, structure optimization, and experimental research of the subsequent ocean differential circulation heat transfer. Full article

(This article belongs to the Section Ocean Engineering)

► Show Figures

Figure 1

13 pages, 2020 KB

Open AccessArticle

Analysis of Gene Expression Related to Pigmentation Variation in the Brain Tissue of Starry Flounder (Platichthys stellatus) Using RNA-Seq

by Jinik Hwang and Duk-Young Kang

J. Mar. Sci. Eng. 2025, 13(11), 2190; https://doi.org/10.3390/jmse13112190 - 18 Nov 2025

Viewed by 241

Abstract

Starry flounder (Platichthys stellatus) is extensively farmed in Korea, and the importance of aquaculture technology in the economic and industrial sectors continues to grow. However, pigmentation anomalies, such as skin discoloration during farming, have resulted in significant economic losses. Despite continuous [...] Read more.

Starry flounder (Platichthys stellatus) is extensively farmed in Korea, and the importance of aquaculture technology in the economic and industrial sectors continues to grow. However, pigmentation anomalies, such as skin discoloration during farming, have resulted in significant economic losses. Despite continuous research to uncover the underlying causes, genomic research in this area remains insufficient. This study utilized RNA-seq with de novo assembly analysis to establish candidate genes in brain tissue related to pigmentation variation in P. stellatus. Genes associated with albinism and melanism were identified, with 1053 genes linked to albinism and 642 genes associated with melanism. Functional analysis of these genes was also conducted using gene ontology analysis, categorizing the genes according to biological processes, cellular components, and molecular functions. KEGG pathway analysis revealed significant associations with five pathways for albinism and two pathways for melanism in brain tissue. The large-scale gene expression profiles identified in this study provide valuable genomic resources for future studies of aquaculture species, including P. stellatus. While the findings provide valuable genomic insights, the study was limited to brain tissue analysis and requires further gene-level validation. Full article

(This article belongs to the Section Marine Aquaculture)

► Show Figures

Figure 1

25 pages, 5494 KB

Open AccessArticle

UW-YOLO-Bio: A Real-Time Lightweight Detector for Underwater Biological Perception with Global and Regional Context Awareness

by Wenhao Zhou, Junbao Zeng, Shuo Li and Yuexing Zhang

J. Mar. Sci. Eng. 2025, 13(11), 2189; https://doi.org/10.3390/jmse13112189 - 18 Nov 2025

Viewed by 279

Abstract

Accurate biological detection is crucial for autonomous navigation of underwater robots, yet severely challenged by optical degradation and scale variation in marine environments. While image enhancement and domain adaptation methods offer some mitigation, they often operate as disjointed preprocessing steps, potentially introducing artifacts [...] Read more.

Accurate biological detection is crucial for autonomous navigation of underwater robots, yet severely challenged by optical degradation and scale variation in marine environments. While image enhancement and domain adaptation methods offer some mitigation, they often operate as disjointed preprocessing steps, potentially introducing artifacts and compromising downstream detection performance. Furthermore, existing architectures struggle to balance accuracy, computational efficiency, and robustness across the extreme scale variability of marine organisms in challenging underwater conditions. To overcome these limitations, we propose UW-YOLO-Bio, a novel framework built upon the YOLOv8 architecture. Our approach integrates three dedicated modules: (1) The Global Context 3D Perception Module (GCPM), which captures long-range dependencies to mitigate occlusion and noise without the quadratic cost of self-attention; (2) The Channel-Aggregation Efficient Downsampling Block (CAEDB), which preserves critical information from low-contrast targets during spatial reduction; (3) The Regional Context Feature Pyramid Network (RCFPN), which optimizes multi-scale fusion with contextual awareness for small marine organisms. Extensive evaluations on DUO, RUOD, and URPC datasets demonstrate state-of-the-art performance, achieving an average improvement in mAP50 of up to 2.0% across benchmarks while simultaneously reducing model parameters by 8.3%. Notably, it maintains a real-time inference speed of 61.8 FPS, rendering it highly suitable for deployment on resource-constrained autonomous underwater vehicles (AUVs). Full article

(This article belongs to the Topic Applications and Development of Underwater Robotics and Underwater Vision Technology, 2nd Edition)

► Show Figures

Figure 1

30 pages, 5775 KB

Open AccessArticle

Research on Instantaneous Sediment Concentration in Muddy Coastal Waters Under Extreme Weather Conditions

by Qinghui Qi, Dong Xu and Youbin Ding

J. Mar. Sci. Eng. 2025, 13(11), 2188; https://doi.org/10.3390/jmse13112188 - 18 Nov 2025

Viewed by 273

Abstract

This study addresses a fundamental limitation inherent in conventional sediment transport capacity formulas—their failure to accurately capture real-time fluctuations in suspended sediment concentration. Leveraging extensive synchronous field measurements of waves, currents, and sediment dynamics from muddy coastal zones, we integrate theoretical derivation with [...] Read more.

This study addresses a fundamental limitation inherent in conventional sediment transport capacity formulas—their failure to accurately capture real-time fluctuations in suspended sediment concentration. Leveraging extensive synchronous field measurements of waves, currents, and sediment dynamics from muddy coastal zones, we integrate theoretical derivation with comprehensive data analysis to investigate the complex and transient behavior of instantaneous sediment concentration under extreme weather conditions. This study elucidates the dynamic response mechanisms of instantaneous sediment concentration to wave–current interactions, culminating in a novel formulation that incorporates the effects of velocity phase lag and wave energy dissipation. Validation against field measurements demonstrates that the proposed formula shows marked improvement over traditional sediment transport formulas in predicting sediment concentration during extreme events. This advancement provides more reliable sediment boundary conditions for numerical sediment transport modeling and establishes a new methodological framework for investigating sediment dynamics in muddy coastal environments. Full article

(This article belongs to the Section Coastal Engineering)

► Show Figures

Figure 1

22 pages, 875 KB

Open AccessArticle

Water-State-Aware Spatiotemporal Graph Transformer Network for Water-Level Prediction

by Ziang Li, Wenru Zhang, Zongying Liu, Shaoxi Li, Jiangling Hao and Chu Kiong Loo

J. Mar. Sci. Eng. 2025, 13(11), 2187; https://doi.org/10.3390/jmse13112187 - 18 Nov 2025

Viewed by 272

Abstract

Accurate water-level prediction is a critical component for ensuring safe maritime navigation, optimizing port operations, and mitigating coastal flooding risks. However, the complex, non-linear spatiotemporal dynamics of water systems pose significant challenges for current forecasting models. The proposed framework introduces three key innovations. [...] Read more.

Accurate water-level prediction is a critical component for ensuring safe maritime navigation, optimizing port operations, and mitigating coastal flooding risks. However, the complex, non-linear spatiotemporal dynamics of water systems pose significant challenges for current forecasting models. The proposed framework introduces three key innovations. First, a dual-weight graph construction mechanism integrates geographical proximity with Dynamic Time Warping (DTW)-derived temporal similarity to better represent hydrodynamic connectivity in coastal and estuarine environments. Second, a state-aware weighted loss function is designed to enhance predictive accuracy during critical hydrological events, such as storm surges and extreme tides, by prioritizing the reduction in errors in these high-risk periods. Third, the WS-STGTN architecture combines graph attention with temporal self-attention to capture long-range dependencies in both space and time. Extensive experiments are conducted using water-level data from five stations in the tidal-influenced lower Yangtze River, a vital artery for shipping and a region susceptible to coastal hydrological extremes. The results demonstrate that the model consistently surpasses a range of baseline methods. Notably, the WS-STGTN achieves an average reduction in Mean Squared Error (MSE) of 27.6% compared to the standard Transformer model, along with the highest coefficient of determination (

R^{2} \approx 0.96

) across all datasets, indicating its stronger explanatory power for observed water-level variability. This work provides a powerful tool that can be directly applied to improve coastal risk management, marine navigation safety, and the operational planning of port and coastal engineering projects. Full article

(This article belongs to the Section Ocean Engineering)

► Show Figures

Figure 1

17 pages, 3756 KB

Open AccessArticle

Study on Cyclic Tensile Shakedown Behaviour of Flexible Risers Considering Winding Process

by Shanghua Wu, Junyu Liu, Ersu Shang, Xiufeng Yue and Zhuoyuan Shen

J. Mar. Sci. Eng. 2025, 13(11), 2186; https://doi.org/10.3390/jmse13112186 - 18 Nov 2025

Viewed by 252

Abstract

Flexible risers are subjected to significant tensile loads during manufacturing, installation, and in-service phases, and they experience multiple cyclic tensile loads throughout their entire service life. Whether the armour wires can achieve shakedown under cyclic tensile loads remains an open question to be [...] Read more.

Flexible risers are subjected to significant tensile loads during manufacturing, installation, and in-service phases, and they experience multiple cyclic tensile loads throughout their entire service life. Whether the armour wires can achieve shakedown under cyclic tensile loads remains an open question to be investigated. In this study, first, the winding process of the tensile armour layers was explored, and the residual stress distribution in the cross-section of the armour wires after the winding process was obtained. Subsequently, a numerical simulation model of the flexible riser that considers residual stress was established based on the ABAQUS 2021 software to study the shakedown behaviour of the flexible riser under cyclic tensile loads. The results show that, during the initial loading–unloading process of the example pipe, the stress in the armour wire cross-section undergoes obvious redistribution. When cyclic loading is applied with a tensile force range of 0–16.1 kN, the armour wire cross-section tends to reach a shakedown state as the number of loading cycles increases. However, when cyclic loading is applied with a tensile force range of 0–30.2 kN, the strain of the armour wire cross-section gradually increases with each loading–unloading cycle, thus exhibiting a ratcheting effect. The cyclic tensile shakedown prediction model proposed in this study can provide a reference for the design of armour layers in deepwater flexible risers. Full article

(This article belongs to the Special Issue Advanced Research in Flexible Riser and Pipelines)

► Show Figures

Figure 1

24 pages, 4400 KB

Open AccessArticle

Engineering Critical Assessment of IMO Type C Tanks: A Comparative Study of Shell and Solid Element Models

by Dong In Kim, Nak-Kyun Cho, Jin-Ha Hwang, Yu Yao Lin and Do Kyun Kim

J. Mar. Sci. Eng. 2025, 13(11), 2185; https://doi.org/10.3390/jmse13112185 - 18 Nov 2025

Viewed by 321

Abstract

In the present study, an Engineering Critical Assessment (ECA) is conducted for an International Maritime Organisation (IMO) Type C liquefied CO₂ (LCO₂) cargo tank to evaluate the effect of finite element configuration on structural integrity in the presence of potential [...] Read more.

In the present study, an Engineering Critical Assessment (ECA) is conducted for an International Maritime Organisation (IMO) Type C liquefied CO₂ (LCO₂) cargo tank to evaluate the effect of finite element configuration on structural integrity in the presence of potential flaws. With the increasing demand for LCO₂ carriers to support carbon capture, utilisation, and storage (CCUS), conventional stress-based design approaches outlined in the International Gas Carrier (IGC) Code have limitations because they neglect imperfections resulting from fabrication and material. To assess these flaws, the fracture mechanics-based ECA methodology, as prescribed by the BS 7910 standard, is applied to a bilobe IMO type C tank designed for cryogenic and pressurised conditions. The assessment integrates fracture toughness, stress intensity factor, and applied loads. Both the two-dimensional shell element model and the three-dimensional solid element model are developed and compared in terms of stress distribution, safety factor for fracture, and fatigue crack growth predictions. Results show that while shell models offer computational efficiency, solid models capture bending stresses and stress concentrations at geometric discontinuities more accurately, resulting in higher reliability in ECA outcomes. The comparative analysis highlights that the web and butt weld near the centre bulkhead are the most vulnerable regions, and fatigue crack growth is highly sensitive to input data, such as stress intensity factor range and fatigue crack growth laws. These findings provide practical guidance for applying ECA in bilobe LCO₂ tank design and safety assessment. Full article

(This article belongs to the Special Issue Advances in Marine Mechanical and Structural Engineering—2nd Edition)

► Show Figures

Figure 1

Journal Menu

Journal Browser

J. Mar. Sci. Eng., Volume 13, Issue 11 (November 2025) – 192 articles

Further Information

Guidelines

MDPI Initiatives

Follow MDPI