Journal of Marine Science and Engineering

29 pages, 15477 KiB

Open AccessArticle

Geometric and Mechanical Analysis of Selenium-Enriched Eggs

by Huinan Kang, Yunsen Hu, Sakdirat Kaewunruen, Xiaozhi Hu and Jian Zhang

J. Mar. Sci. Eng. 2025, 13(3), 525; https://doi.org/10.3390/jmse13030525 (registering DOI) - 9 Mar 2025

Geometric and mechanical analyses were performed on 82 selenium-rich eggs, which underwent hydrostatic testing as 2 raw eggs, 60 steamed eggs, and 20 emptied eggshells. By analyzing the geometric and mechanical properties of the egg, we can draw inspiration from its structural design [...] Read more.

Geometric and mechanical analyses were performed on 82 selenium-rich eggs, which underwent hydrostatic testing as 2 raw eggs, 60 steamed eggs, and 20 emptied eggshells. By analyzing the geometric and mechanical properties of the egg, we can draw inspiration from its structural design to create a pressure shell capable of effectively withstanding the immense water pressure in deep-sea environments. The major axis, minor axis, egg-shape coefficient, weight, thickness, volume, superficial area, and ultimate compressive strength were measured, and their correlations were analyzed. The thickness, egg-shape coefficient, and ultimate compressive strength were normally distributed, and many parameters were strongly correlated. Moreover, finite element analysis was conducted to evaluate the compressive resistance of egg-like pressure shells made from different materials, including metal, ceramic, resin, and selenium-enriched eggshell materials. The performance ratio of the ceramic shells was 2.6 times higher than that of eggshells, and eggshells outperformed metal and resin shells by factors of 2.14 and 4.49, respectively. The eggshells had excellent compression resistance. These findings offer novel insights into the design and optimization of egg-like pressure shells. Full article

(This article belongs to the Special Issue Advancements in Deep-Sea Equipment and Technology, 3rd Edition)

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13 pages, 5926 KiB

Open AccessArticle

Long-Term (1979–2024) Variation Trend in Wave Power in the South China Sea

by Yifeng Tong, Junmin Li, Wuyang Chen and Bo Li

J. Mar. Sci. Eng. 2025, 13(3), 524; https://doi.org/10.3390/jmse13030524 (registering DOI) - 9 Mar 2025

Abstract

Wave power (WP) is a strategic oceanic resource. Previous studies have extensively researched the long-term variations in WP in the South China Sea (SCS) for energy planning and utilization. This study extends the analysis of long-term trends to the last year based on [...] Read more.

Wave power (WP) is a strategic oceanic resource. Previous studies have extensively researched the long-term variations in WP in the South China Sea (SCS) for energy planning and utilization. This study extends the analysis of long-term trends to the last year based on ERA5 (European Centre for Medium-Range Weather Forecasts Reanalysis v5) reanalysis data from 1979 to 2024. Our results mainly indicate that the trends in WP after 2011 are significantly different from those before 2011. Before 2011, the WP in the SCS primarily showed an increasing trend, but, after 2011, it shifted to a decreasing trend. This trend has seasonal differences, manifested as being consistent with the annual trend in winter and spring while being inconsistent with the annual trend in summer and autumn. It indicates that the opposite trend in WP before and after 2011 was mainly the result of WP variations in winter and spring. To illustrate the driving factor for the WP’s variations, the contemporary long-term trend of the wind fields is systematically analyzed. Analysis results reveal that, regardless of seasonal differences or spatial distribution, the two trends are consistent in most situations, indicating that wind fields are the dominant factor for the long-term variations in WP. Meanwhile, the effects of the wind fields on the WP variations can also be modulated by environmental factors such as oceanic swell propagation and local topography. This study contributes to the knowledge of the latest trends and driving factors regarding the WP in the SCS. Full article

(This article belongs to the Special Issue Advances in Offshore Wind and Wave Energies—2nd Edition)

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19 pages, 3261 KiB

Open AccessArticle

Risk Assessment of Hydrogen Fuel System Leakage in Ships Based on Noisy-OR Gate Model Bayesian Network

by Gen Li, Haidong Zhang, Shibo Li and Chunchang Zhang

J. Mar. Sci. Eng. 2025, 13(3), 523; https://doi.org/10.3390/jmse13030523 (registering DOI) - 9 Mar 2025

Abstract

To mitigate the risk of hydrogen leakage in ship fuel systems powered by internal combustion engines, a Bayesian network model was developed to evaluate the risk of hydrogen fuel leakage. In conjunction with the Bow-tie model, fuzzy set theory, and the Noisy-OR Gate [...] Read more.

To mitigate the risk of hydrogen leakage in ship fuel systems powered by internal combustion engines, a Bayesian network model was developed to evaluate the risk of hydrogen fuel leakage. In conjunction with the Bow-tie model, fuzzy set theory, and the Noisy-OR Gate model, an in-depth analysis was also conducted to examine both the causal factors and potential consequences of such incidents. The Bayesian network model estimates the likelihood of hydrogen leakage at approximately 4.73 × 10⁻⁴ and identifies key risk factors contributing to such events, including improper maintenance procedures, inadequate operational protocols, and insufficient operator training. The Bow-tie model is employed to visualize the causal relationships between risk factors and their potential consequences, providing a clear structure for understanding the events leading to hydrogen leakage. Fuzzy set theory is used to address the uncertainties in expert judgments regarding system parameters, enhancing the robustness of the risk analysis. To mitigate the subjectivity inherent in root node probabilities and conditional probability tables, the Noisy-OR Gate model is introduced, simplifying the determination of conditional probabilities and improving the accuracy of the evaluation. The probabilities of flash or pool fires, jet fires, and vapor cloud explosions following a leakage are calculated as 4.84 × 10⁻⁵, 5.15 × 10⁻⁵, and 4.89 × 10⁻⁷, respectively. These findings highlight the importance of strengthening operator training and enforcing stringent maintenance protocols to mitigate the risks of hydrogen leakage. The model provides a valuable framework for safety evaluation and leakage risk management in hydrogen-powered ship fuel systems. Full article

(This article belongs to the Special Issue Smart and Low Carbon Emission-Oriented Maritime Traffic Management and Controlling)

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16 pages, 2166 KiB

Open AccessArticle

Design of Encoding Algorithm for Underwater Wireless Optical Communication Based on Spinal Code

by Xiaoyang Yu, Min Yu, Yun Zhou and Tianwei Chen

J. Mar. Sci. Eng. 2025, 13(3), 522; https://doi.org/10.3390/jmse13030522 (registering DOI) - 9 Mar 2025

Abstract

The marine environment is complex and variable, with the absorption and scattering effects of seawater and turbulence causing significant attenuation of received optical signals and introducing random jitter, which limits the communication range and stability of underwater wireless optical communication systems. This paper [...] Read more.

The marine environment is complex and variable, with the absorption and scattering effects of seawater and turbulence causing significant attenuation of received optical signals and introducing random jitter, which limits the communication range and stability of underwater wireless optical communication systems. This paper presents the Superposition UEP-Spinal Code structure, which utilizes unequal error protection (UEP) to adjust the transmission performance of different types of information in underwater composite data communication by adjusting the superposition weighting factors in the encoding algorithm. This encoding method enhances the noise immunity of important data, and with the same bandwidth utilization, the overall decoding complexity is reduced by 13.3% compared to the previously improved Spinal code encoding algorithm. The results show that the Superposition UEP-Spinal Code provides a more stable, reliable, and efficient communication solution for underwater wireless optical communication systems with randomly varying channel conditions. Full article

(This article belongs to the Section Ocean Engineering)

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22 pages, 9467 KiB

Open AccessArticle

Study on the Dynamic Characteristics of Floating Production Storage and Offloading Units and Steel Catenary Risers Under the Action of Internal Solitary Waves

by Fengming Du, Mingjie Li, Zetian Mi and Pan Gao

J. Mar. Sci. Eng. 2025, 13(3), 521; https://doi.org/10.3390/jmse13030521 (registering DOI) - 9 Mar 2025

Abstract

In the ocean, internal solitary waves (ISW) pose a serious threat to the safety of marine engineering structures such as floating production storage and offloading (FPSO) units and steel catenary risers (SCRs). In this work, a calculation method for the load acting on [...] Read more.

In the ocean, internal solitary waves (ISW) pose a serious threat to the safety of marine engineering structures such as floating production storage and offloading (FPSO) units and steel catenary risers (SCRs). In this work, a calculation method for the load acting on an FPSO by internal solitary waves and a calculation method for the cable recovery force were proposed, the motion characteristics of the FPSO under the action of internal solitary waves were analyzed, and the dynamic characteristics of SRCs were further studied. The results show that that the internal solitary wave load reaches its maximum value before the ISW reaches the FPSO position, and the displacement reaches its maximum value around the time when the ISW reaches the FPSO position. The smaller the horizontal pre-tension of the mooring cable, the greater the displacement of the FPSO. The stress of the SRC reaches its maximum value when the FPSO reaches its maximum displacement, while it reaches its minimum value when the FPSO reaches its minimum motion. As the incident angle of the ISW increases, the stress of the SCRs slightly decreases. This model and the findings can provide a technical support and guidance for the design of FPSOs and SCRs. Full article

(This article belongs to the Special Issue Numerical Modeling of Fluid-Structure Interactions in Ocean Engineering)

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19 pages, 38097 KiB

Open AccessArticle

Sediment Provenance and Facies Analysis of the Huagang Formation in the Y-Area of the Central Anticlinal Zone, Xihu Sag, East China Sea

by Xiao Ma, Wei Yan, Yi Yang, Ru Sun, Yue Chao, Guoqing Zhang, Chao Yang, Shudi Zhang, Dapeng Su, Guangxue Zhang and Hong Xu

J. Mar. Sci. Eng. 2025, 13(3), 520; https://doi.org/10.3390/jmse13030520 (registering DOI) - 9 Mar 2025

Abstract

Recent breakthrough exploration wells in the Huagang Formation in the Y-area of the central anticlinal zone of the Xihu Sag have confirmed the significant exploration potential of structure–lithology complex hydrocarbon reservoirs. However, limited understanding of the provenance system, sedimentary facies, and microfacies has [...] Read more.

Recent breakthrough exploration wells in the Huagang Formation in the Y-area of the central anticlinal zone of the Xihu Sag have confirmed the significant exploration potential of structure–lithology complex hydrocarbon reservoirs. However, limited understanding of the provenance system, sedimentary facies, and microfacies has hindered further progress in complex hydrocarbon exploration. Analysis of high-precision stratigraphic sequences and seismic facies data, mudstone core color, grain-size probability cumulative curves, core facies, well logging facies, lithic type, the heavy-mineral ZTR index, and conglomerate combinations in drilling sands reveals characteristics of the source sink system and provenance direction. The Huagang Formation in the Y-area represents an overall continental fluvial delta sedimentary system that evolved from a braided river delta front deposit into a meandering river channel large-scale river deposit. The results indicate that the primary provenance of the Huagang Formation in the Y-area of the Xihu Sag is the long-axis provenance of the Hupi Reef bulge in the northeast, with supplementary input from the short-axis provenance of the western reef bulge. Geochemical analysis of wells F1, F3, and G in the study area suggests that the prevailing sedimentary environment during the period under investigation was characterized by anoxic conditions in nearshore shallow waters. This confirms previous research indicating strong tectonic reversal in the northeast and a small thickness of the central sand body unrelated to the flank slope provenance system. The aforementioned findings deviate from conventional understanding and will serve as a valuable point of reference for future breakthroughs in exploration. Full article

(This article belongs to the Special Issue Recent Developments and Advances in Geological Oceanography and Ocean Observation in the Pacific Ocean and Its Marginal Basins—2nd Edition)

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22 pages, 8660 KiB

Open AccessArticle

Ship Contour: A Novel Ship Instance Segmentation Method Using Deep Snake and Attention Mechanism

by Chen Chen, Songtao Hu, Feng Ma, Jie Sun, Tao Lu and Bing Wu

J. Mar. Sci. Eng. 2025, 13(3), 519; https://doi.org/10.3390/jmse13030519 (registering DOI) - 8 Mar 2025

Abstract

Ship instance segmentation technologies enable the identification of ship targets and their contours, serving as an auxiliary tool for monitoring, tracking, and providing critical support for maritime and port safety management. However, due to the different shapes and sizes of ships, as well [...] Read more.

Ship instance segmentation technologies enable the identification of ship targets and their contours, serving as an auxiliary tool for monitoring, tracking, and providing critical support for maritime and port safety management. However, due to the different shapes and sizes of ships, as well as the complexity and fluctuation of lighting and weather, existing ship instance segmentation approaches frequently struggle to accomplish correct contour segmentation. To address this issue, this paper introduces Ship Contour, a real-time segmentation method for ship instances based on contours that detects ship targets using an improved CenterNet algorithm. This method utilizes DLA-60 (deep layer aggregation) as the core network to ensure detection accuracy and speed, and it integrates an efficient channel attention (ECA) mechanism to boost feature extraction capability. Furthermore, a Mish activation function replaces ReLU to better adapt deep network learning. These improvements to CenterNet enhance model robustness and effectively reduce missed and false detection. In response to the issue of low accuracy in extracting ship target edge contours using the original deep snake end-to-end method, a scale- and translation-invariant normalization scheme is employed to enhance contour quality. To validate the effectiveness of the proposed method, this research builds a dedicated dataset with up to 2300 images. Experiments demonstrate that this method achieves competitive performance, with an accuracy rate of AP_0.5:0.95 reaching 63.6% and a recall rate of AR_0.5:0.95 reaching 67.4%. Full article

(This article belongs to the Section Ocean Engineering)

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23 pages, 1647 KiB

Open AccessArticle

ShipNetSim: An Open-Source Simulator for Real-Time Energy Consumption and Emission Analysis in Large-Scale Maritime Networks

by Ahmed Aredah and Hesham A. Rakha

J. Mar. Sci. Eng. 2025, 13(3), 518; https://doi.org/10.3390/jmse13030518 (registering DOI) - 8 Mar 2025

Abstract

The imperative of decarbonization in maritime shipping is underscored by the sector’s sizeable contribution to worldwide greenhouse gas emissions. ShipNetSim, an open-source multi-ship simulator created in this study, combines state-of-the-art hydrodynamic modeling, dynamic ship-following techniques, real-time environmental data, and cybersecurity threat simulation to [...] Read more.

The imperative of decarbonization in maritime shipping is underscored by the sector’s sizeable contribution to worldwide greenhouse gas emissions. ShipNetSim, an open-source multi-ship simulator created in this study, combines state-of-the-art hydrodynamic modeling, dynamic ship-following techniques, real-time environmental data, and cybersecurity threat simulation to quantify and evaluate marine fuel consumption and CO

_{2}

emissions. ShipNetSim uses well-validated approaches, such as the Holtrop resistance and B-Series propeller analysis with a ship-following model inspired by traffic flow theory, augmented with a novel module simulating cyber threats (e.g., GPS spoofing) to evaluate operational efficiency and resilience. In a case study simulation of the journey of an S175 container vessel from Savannah to Algeciras, the simulator estimated the total fuel consumption to be 478 tons of heavy fuel oil and approximately 1495 tons of CO

_{2}

emissions for a trip of 7 days and 15 h within 13.1% of reported operational estimates. A twelve-month sensitivity analysis revealed a marginal 1.5% range of fuel consumption variation, demonstrating limiting variability for different environmental conditions. ShipNetSim not only yields realistic predictions of energy consumption and emissions but is also demonstrated to be a credible framework for the evaluation of operational scenarios—including speed adjustment, optimized routing, and alternative fuel strategies—that directly contribute to reducing the marine carbon footprint. This capability supports industry stakeholders and policymakers in achieving compliance with global decarbonization targets, such as those established by the International Maritime Organization (IMO). Full article

(This article belongs to the Section Marine Energy)

20 pages, 122916 KiB

Open AccessArticle

A Reef’s High-Frequency Soundscape and the Effect on Telemetry Efforts: A Biotic and Abiotic Balance

by Frank McQuarrie, Jr., C. Brock Woodson and Catherine R. Edwards

J. Mar. Sci. Eng. 2025, 13(3), 517; https://doi.org/10.3390/jmse13030517 - 7 Mar 2025

Abstract

Acoustic telemetry is a tool for tracking animals, but transmitted signals from tagged animals are not always detected. Detection efficiency declines with increasing background noise, which can have both abiotic and biotic sources. The abiotic noise present in reef environments (waves, bubbles, etc.) [...] Read more.

Acoustic telemetry is a tool for tracking animals, but transmitted signals from tagged animals are not always detected. Detection efficiency declines with increasing background noise, which can have both abiotic and biotic sources. The abiotic noise present in reef environments (waves, bubbles, etc.) is primarily low-frequency, but snapping shrimp create high-frequency noise that can interfere with transmission detections. Prior work in shallow coastal reefs correlated winds with less high-frequency background noise, and hypothesized that it was due to a balance of biotic and/or abiotic factors: shrimp may be less active during high wind events, and sound attenuation at the surface increases with wave height. To test this hypothesis, passive acoustic recordings from a live-bottom reef are used to quantify snapping shrimp snap rate. Snap rate was strongly correlated with temperature, and warmer environments appeared to be challenging for acoustic telemetry. However, the majority of synoptic variability in noise is shown to be driven by abiotic attenuation. Wind speed has little to no effect on snapping shrimp behavior, but has a significant inverse correlation with high-frequency noise levels due to surface attenuation of high-frequency noise, and therefore a positive effect on detection efficiency, pointing to primarily abiotic forcing behind noise variability and resulting telemetry success. This research gives context to previously collected detection data and can be leveraged to help plan future acoustic arrays in shallow, complex, and/or noisy environments, potentially predicting changes in detection range. Full article

(This article belongs to the Special Issue Recent Advances in Marine Bioacoustics)

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13 pages, 2203 KiB

Open AccessArticle

The Integration of a Medium-Resolution Underwater Radioactivity System in the COSYNA Observing System at Helgoland Island, Germany

by Christos Tsabaris, Stylianos Alexakis, Miriam Lienkämper, Max Schwanitz, Markus Brand, Manolis Ntoumas, Dionisis L. Patiris, Effrosyni G. Androulakaki and Philipp Fischer

J. Mar. Sci. Eng. 2025, 13(3), 516; https://doi.org/10.3390/jmse13030516 - 6 Mar 2025

Abstract

The continuous monitoring of radioactivity in a cabled subsea network in the North Sea Observatory was performed to test the performance of a medium-resolution underwater spectrometer, as well as to identify and to assess potential anthropogenic and/or natural hazards. The effectiveness of continuous [...] Read more.

The continuous monitoring of radioactivity in a cabled subsea network in the North Sea Observatory was performed to test the performance of a medium-resolution underwater spectrometer, as well as to identify and to assess potential anthropogenic and/or natural hazards. The effectiveness of continuous monitoring was tested together with the operability of the underwater sensor, and quantification methods were optimized to identify the type of radioactivity as well as the activity concentration of radionuclides in the seawater. In the frame of the RADCONNECT project, a medium-resolution underwater radioactivity system named GeoMAREA was integrated into an existing cabled ocean observatory placed on Helgoland Island (COSYNA network). The system could be operated via an online mode controlled by the operational centre (AWI), as well as remotely by the end-user (HCMR). The system provided gamma-ray spectra and activity concentrations of key radionuclides that were enriched in seawater during the monitoring period. As concerns the quantification method of natural radioactivity, the average activity concentrations (in terms of the total monitoring period) of ²¹⁴Bi, ²⁰⁸Tl, ²²⁸Ac and ⁴⁰K were found to be 108 ± 30, 57 ± 14, 40 ± 5 and 9800 ± 500 Bqm⁻³, respectively. As concerns the quantification of ¹³⁷Cs, the average activity concentration in terms of the total monitoring period (although it is uncertain) was found to be 6 ± 4 Bqm⁻³. The data analysis proved that the system had a stable operation in terms of voltage stability, so all acquired spectra could be summed up efficiently in time to produce statistically optimal gamma-ray spectra for further analysis. Full article

(This article belongs to the Special Issue Research Progress on Ocean Observations Technology and Information Systems)

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30 pages, 8502 KiB

Open AccessArticle

Dynamic Structural Behavior of Monopile Support Structure for 15 MW Offshore Wind Turbine During Different Phases of Operation

by Sajid Ali, Muhammad Waleed and Daeyong Lee

J. Mar. Sci. Eng. 2025, 13(3), 515; https://doi.org/10.3390/jmse13030515 - 6 Mar 2025

Abstract

The structural integrity of offshore wind turbine monopiles is critical for ensuring operational stability and long-term performance under varying environmental and aerodynamic loads. However, transient load conditions during different operational phases, such as start, normal stop, and emergency stop, can significantly impact structural [...] Read more.

The structural integrity of offshore wind turbine monopiles is critical for ensuring operational stability and long-term performance under varying environmental and aerodynamic loads. However, transient load conditions during different operational phases, such as start, normal stop, and emergency stop, can significantly impact structural behavior, influencing fatigue life and dynamic stability. This study investigates the dynamic structural response of a 15 MW offshore wind turbine monopile, incorporating modal analysis and transient simulations to assess deflection, forces, moments, and rotational displacements at the mud-line. The modal analysis revealed natural frequencies of 0.509492 Hz, 1.51616 Hz, and 3.078425 Hz for the blade’s flap-wise modes, while side-to-side modes for the combined tower and monopile structure were identified at 0.17593 Hz, 0.922308 Hz, and 1.650862 Hz. These frequencies are crucial in evaluating resonance risks and ensuring dynamic stability under combined aerodynamic and hydrodynamic forces. The transient analysis demonstrated that lateral force (F_y) variations peaked at −2500 kN during emergency stop, while moment fluctuations (My) reached ±100,000 kNm, reflecting the monopile’s high dynamic sensitivity under sudden aerodynamic unloading. Rotational displacements also showed significant variations, with θx oscillating up to ±0.0009 degrees and θy between −0.0022 and −0.0027 degrees. These findings provide valuable insights into optimizing monopile design to mitigate resonance effects, improve fatigue performance, and enhance structural resilience for large-scale offshore wind turbine support systems. Full article

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30 pages, 8829 KiB

Open AccessArticle

Adaptive Temporal Reinforcement Learning for Mapping Complex Maritime Environmental State Spaces in Autonomous Ship Navigation

by Ruolan Zhang, Xinyu Qin, Mingyang Pan, Shaoxi Li and Helong Shen

J. Mar. Sci. Eng. 2025, 13(3), 514; https://doi.org/10.3390/jmse13030514 - 6 Mar 2025

Abstract

The autonomous decision-making model for ship navigation requires extensive interaction and trial-and-error in real, complex environments to ensure optimal decision-making performance and efficiency across various scenarios. However, existing approaches still encounter significant challenges in addressing the temporal features of state space and tackling [...] Read more.

The autonomous decision-making model for ship navigation requires extensive interaction and trial-and-error in real, complex environments to ensure optimal decision-making performance and efficiency across various scenarios. However, existing approaches still encounter significant challenges in addressing the temporal features of state space and tackling complex dynamic collision avoidance tasks, primarily due to factors such as environmental uncertainty, the high dimensionality of the state space, and limited decision robustness. This paper proposes an adaptive temporal decision-making model based on reinforcement learning, which utilizes Long Short-Term Memory (LSTM) networks to capture temporal features of the state space. The model integrates an enhanced Proximal Policy Optimization (PPO) algorithm for efficient policy iteration optimization. Additionally, a simulation training environment is constructed, incorporating multi-factor coupled physical properties and ship dynamics equations. The environment maps variables such as wind speed, current velocity, and wave height, along with dynamic ship parameters, while considering the International Regulations for Preventing Collisions at Sea (COLREGs) in training the autonomous navigation decision-making model. Experimental results demonstrate that, compared to other neural network-based reinforcement learning methods, the proposed model excels in environmental adaptability, collision avoidance success rate, navigation stability, and trajectory optimization. The model’s decision resilience and state-space mapping align with real-world navigation scenarios, significantly improving the autonomous decision-making capability of ships in dynamic sea conditions and providing critical support for the advancement of intelligent shipping. Full article

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30 pages, 11299 KiB

Open AccessArticle

Study on the Effects of Internal Building Layouts on Tsunami-Driven Single-Container Motion

by Yudou Hou, Tomoaki Nakamura, Yong-Hwan Cho and Norimi Mizutani

J. Mar. Sci. Eng. 2025, 13(3), 513; https://doi.org/10.3390/jmse13030513 - 6 Mar 2025

Abstract

This study investigated the complex interactions among tsunamis, debris, and coastal building structures under extreme hydrodynamic conditions. We performed numerical simulations to explore the influence of varying wave conditions, debris, and building designs to identify the most vulnerable parts of a building structure. [...] Read more.

This study investigated the complex interactions among tsunamis, debris, and coastal building structures under extreme hydrodynamic conditions. We performed numerical simulations to explore the influence of varying wave conditions, debris, and building designs to identify the most vulnerable parts of a building structure. The three-dimensional coupled fluid–structure–sediment–seabed interaction model (FS3M) was employed to simulate these interactions and validated against physical experimental data to ensure accuracy. The results revealed that debris significantly altered the wave impact dynamics, increasing the force exerted on buildings regardless of their structural features. This study provides relevant insights into the effectiveness of different building layouts in mitigating damage, highlighting the critical role of buildings with internal walls perpendicular to the wave direction, which significantly mitigated the tsunami’s impact at specific regions. Full article

(This article belongs to the Special Issue Advanced Studies in Marine Geomechanics and Geotechnics)

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18 pages, 7850 KiB

Open AccessArticle

Gastrointestinal Helminthofauna of Mediterranean Elasmobranchs

by Perla Tedesco, Enrico Liborio Quadrone, Linda Albonetti, Federica Marcer, Monica Caffara, Maria Letizia Fioravanti, Fausto Tinti and Andrea Gustinelli

J. Mar. Sci. Eng. 2025, 13(3), 512; https://doi.org/10.3390/jmse13030512 - 5 Mar 2025

Abstract

Elasmobranchs (Chondrichthyes, Elasmobranchii) are exposed to a variety of gastrointestinal parasites acquired through the ingestion of infected prey. An increasing amount of evidence suggests the usefulness of parasitological information to elucidate aspects of the biology and ecology of sharks and rays, to inform [...] Read more.

Elasmobranchs (Chondrichthyes, Elasmobranchii) are exposed to a variety of gastrointestinal parasites acquired through the ingestion of infected prey. An increasing amount of evidence suggests the usefulness of parasitological information to elucidate aspects of the biology and ecology of sharks and rays, to inform the correct management and conservation of their stocks and the appropriate husbandry of captive specimens. This study aims to identify at the morphological and molecular level the helminth parasites found in the stomachs and intestines of various elasmobranchs accidentally caught by Mediterranean fisheries, with the aim of updating and providing new information on the parasitic fauna of these species. Specimens of smooth-hound Mustelus mustelus, blackspotted smooth-hound Mustelus punctulatus, blue shark Prionace glauca, spiny dogfish Squalus acanthias, lesser-spotted dogfish Scyliorhinus canicula, pelagic stingray Pteroplatytrygon violacea and Mediterranean starry ray Raja asterias were examined. The parasitological examination allowed us to identify the nematode Acanthocheilus rotundatus in the two species of smooth-hounds analyzed, the tapeworm species Scyphophyllidium exiguum, S. prionacis, Anthobothrium caseyi and Nybelinia indica in P. glauca, the nematodes Hysterothylacium aduncum and Proleptus obtusus in S. acanthias and S. canicula, respectively, and finally the nematode Pseudanisakis rajae and the tapeworm Nybelinia sp. in Raja asterias. Some observations represent new reports at a geographical level, in particular, those on A. caseyi in P. glauca and H. aduncum in S. acanthias from the Adriatic Sea, or first host records, such as S. exiguum and N. indica in P. glauca or P. rajae. in R. asterias. The results of this survey represent a contribution to broadening the knowledge of the parasitic fauna of these elasmobranchs in the Mediterranean Sea. From more in-depth future studies, it will be possible to reach more solid evidence and general conclusions on aspects relating to the biology, ecology, and health of the investigated species, offering useful information for their conservation and management. Full article

(This article belongs to the Special Issue Parasites of Marine Fishes: Advances and Perspectives)

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18 pages, 7693 KiB

Open AccessArticle

Numerical Simulation of Natural Gas Hydrate Depressurization Extraction Considering Phase Transition Characteristics

by Qiang Fu, Mingqiang Chen, Weixin Pang and Lirong Dong

J. Mar. Sci. Eng. 2025, 13(3), 511; https://doi.org/10.3390/jmse13030511 - 5 Mar 2025

Abstract

Natural gas hydrate (NGH) is a clean resource characterized by abundant potential reserves, clean combustion, and high energy density. Although significant progress has been made in the development of NGH resources all around the world, challenges still exist that hinder commercial exploitation, such [...] Read more.

Natural gas hydrate (NGH) is a clean resource characterized by abundant potential reserves, clean combustion, and high energy density. Although significant progress has been made in the development of NGH resources all around the world, challenges still exist that hinder commercial exploitation, such as a low daily gas production rate and short steady production periods. One significant reason lies in the complex gas–liquid–solid phase transitions occurring within the formation during production, which lead to changes in flow capacity. Understanding the phase change mechanism of NGH reservoirs will help to further reveal the production increase mechanism. To address the phase transitions’ effect on production, this paper establishes a numerical simulation model for the depressurization exploitation of natural gas hydrates in order to investigate phase transition characteristics at the field scale. First, the phase equilibrium calculation method is presented and the phase equilibrium curve is modified by considering the capillary effect, soluble salt, and surface adsorption. Then, the phase transition model is successfully characterized in a simulation and the numerical simulation model is established based on the first test project parameters in the Shenhu area. The production characteristics of different sediment types (montmorillonite, South China Sea sediments, kaolin, and silt) are analyzed under the effects of water content and salinity. It is shown that lower initial water content and higher salinity result in higher gas production. The results provide a better understanding of the effects of phase transition parameters on NGH production at the field scale. Full article

(This article belongs to the Special Issue Research on Offshore Oil and Gas Numerical Simulation)

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16 pages, 3968 KiB

Open AccessArticle

Energy Saving in Ship Central Cooling Systems: IMC-Tuned PID with Feedforward Control

by Tae-Youl Jeon and Young-Chan Lee

J. Mar. Sci. Eng. 2025, 13(3), 510; https://doi.org/10.3390/jmse13030510 - 5 Mar 2025

Abstract

This study examines the energy savings in a ship’s central cooling system using feedforward control with IMC (Internal Model Control)-based PID tuning. A central cooling system is essential for maintaining the temperature of the engine and other major machinery, thereby improving the overall [...] Read more.

This study examines the energy savings in a ship’s central cooling system using feedforward control with IMC (Internal Model Control)-based PID tuning. A central cooling system is essential for maintaining the temperature of the engine and other major machinery, thereby improving the overall energy efficiency. The seawater pump in the central cooling system consumes a relatively large amount of power, which makes efficient operation essential. This study compared the power consumption of variable-speed seawater pumps based on actual operational data from a ship. By incorporating a feedforward PI controller into the IMC-based PI-PID controller combinations, this study simulated energy savings. The results indicate that the proposed controller combined with the feedforward PI controller reduces the power consumption of seawater pumps compared with conventional methods. Simulation tests were conducted using approximately 11 days of operational data to verify the effectiveness of the proposed control strategy in achieving energy savings. The proposed controller combination saves approximately 277.4 kWh of power over 11 days compared to conventional control methods. Full article

(This article belongs to the Special Issue Maritime Logistics and Green Shipping)

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23 pages, 4134 KiB

Open AccessArticle

Towards a Common Language for Mainstreaming Nature-Based Solutions Through Coastal Systems in the North Sea Region: The Manabas Coast Project

by Geert J. M. van der Meulen, Jurre J. de Vries, Lisa van Well and Frances A. Kannekens

J. Mar. Sci. Eng. 2025, 13(3), 509; https://doi.org/10.3390/jmse13030509 (registering DOI) - 5 Mar 2025

Abstract

Nature-based solutions (NBSs) offer an opportunity to address environmental and societal challenges worldwide while simultaneously providing benefits for human well-being as well as biodiversity. Despite a growing demand and evidence base for NBSs in coastal systems, the scaling of their implementation and mainstreaming [...] Read more.

Nature-based solutions (NBSs) offer an opportunity to address environmental and societal challenges worldwide while simultaneously providing benefits for human well-being as well as biodiversity. Despite a growing demand and evidence base for NBSs in coastal systems, the scaling of their implementation and mainstreaming of their principles in policy and practice are constrained by multiple barriers, such as misinterpretations of concepts, effectiveness, or locked-in preferences or conventions of traditional solutions. To address these constraints, an international consortium of coastal authorities and experts in the North Sea Region collaborates to validate, document, and share learnings of NBSs to establish a framework for mainstreaming NBSs for flood and coastal erosion risk management around the North Sea. Co-creation processes of workshops, field visits, and expert knowledge sessions contributed to a theoretical framework and baseline assessments of exemplary sandy and muddy case study sites in the region, amongst others, iteratively providing and showcasing building blocks for the mainstreaming framework. This article takes stock halfway of the project’s activities, learnings, and status of the called-for common language. Full article

(This article belongs to the Special Issue Nature-Based Solutions in Coastal Systems)

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14 pages, 26658 KiB

Open AccessArticle

Retrieving Palaeoecological Information from Historic Fossil Finds: A Taphonomic Cold Case from Orciano Pisano (Central Italy) Reveals a Distinctive Trophic Interaction in the Pliocene Mediterranean Sea

by Edoardo Terranova, Giovanni Bianucci, Marco Merella, Chiara Sorbini and Alberto Collareta

J. Mar. Sci. Eng. 2025, 13(3), 508; https://doi.org/10.3390/jmse13030508 - 5 Mar 2025

Abstract

Evidence of trophic interactions between sharks and cetaceans is rather widespread in the fossil record, consisting as it does of tooth marks on bones and rarer teeth or tooth fragments embedded in (or associated with) skeletal remains. Here, we reappraise a partial mysticete [...] Read more.

Evidence of trophic interactions between sharks and cetaceans is rather widespread in the fossil record, consisting as it does of tooth marks on bones and rarer teeth or tooth fragments embedded in (or associated with) skeletal remains. Here, we reappraise a partial mysticete (baleen whale) forelimb that was collected more than a century ago from Pliocene deposits exposed at the celebrated fossil locality of Orciano Pisano (Tuscany, central Italy). This specimen, which is revealed to originate from an early juvenile individual, features shark tooth marks on both the humerus and radius. Whether these traces are due to active predation or to scavenging cannot be ascertained. During the Pliocene, the Mediterranean Basin was inhabited by a diverse elasmobranch fauna, including a number of mammal-eating forms that no longer inhabit the Mediterranean Sea (e.g., Galeocerdo and some Carcharhinus spp. as well as the extinct Parotodus). Early juvenile mysticetes were also likely more common than today in the Pliocene Mediterranean Sea, which may have contained balaenid and balaenopterid calving grounds, thus providing the Mediterranean mammal-eating sharks with vulnerable, energetically valuable potential prey items. Thus, our results evoke a kind of trophic interaction that was likely common and ecologically relevant in the Pliocene Mediterranean Sea. Full article

(This article belongs to the Section Marine Biology)

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22 pages, 16367 KiB

Open AccessArticle

Enhanced Seafloor Topography Inversion Using an Attention Channel 1D Convolutional Network Based on Multiparameter Gravity Data: Case Study of the Mariana Trench

by Qiang Wang, Ziyin Wu, Zhaocai Wu, Mingwei Wang, Dineng Zhao, Taoyong Jin, Qile Zhao, Xiaoming Qin, Yang Liu, Yifan Jiang, Puchen Zhao and Ning Zhang

J. Mar. Sci. Eng. 2025, 13(3), 507; https://doi.org/10.3390/jmse13030507 - 5 Mar 2025

Abstract

Seafloor topography data are fundamental for marine resource development, oceanographic research, and maritime rights protection. However, approximately 75% of the ocean remains unsurveyed for bathymetry. Sole reliance on shipborne measurements is insufficient for constructing a global bathymetric model within a short timeframe; consequently, [...] Read more.

Seafloor topography data are fundamental for marine resource development, oceanographic research, and maritime rights protection. However, approximately 75% of the ocean remains unsurveyed for bathymetry. Sole reliance on shipborne measurements is insufficient for constructing a global bathymetric model within a short timeframe; consequently, satellite altimetry-based inversion techniques are essential for filling data gaps. Recent advancements have improved the variety and quality of satellite altimetry gravity data. To leverage the complementary advantages of multiparameter gravity data, we propose a 1D convolutional neural network based on a convolutional attention module, termed the Attention Channel 1D Convolutional Network (AC1D). Results of a case study of the Mariana Trench indicated that the AC1D grid predictions exhibited improved agreement with single-beam depth checkpoints, with standard deviation reductions of 6.32%, 20.79%, and 36.77% and root mean square error reductions of 7.11%, 22.82%, and 50.99% compared with those of parallel linked backpropagation, the gravity–geological method, and a convolutional neural network, respectively. The AC1D grid demonstrated enhanced stability in multibeam bathymetric validation metrics and exhibited better consistency with multibeam bathymetry data and the GEBCO2023 grid. Power spectral density analysis revealed that AC1D effectively captured rich topographic signals when predicting terrain features with wavelengths below 6.33 km. Full article

(This article belongs to the Special Issue Morphological Processes and Evolution of Marine Geomorphology: Observations, Modeling and Applications)

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Journal of Marine Science and Engineering

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