Journal of Marine Science and Engineering

43 pages, 6958 KB

Open AccessReview

From Multi-Field Coupling Behaviors to Self-Powered Monitoring: Triboelectric Nanogenerator Arrays for Deep-Sea Large-Scale Cages

by Kefan Yang, Shengqing Zeng, Keqi Yang, Dapeng Zhang and Yi Zhang

J. Mar. Sci. Eng. 2025, 13(11), 2042; https://doi.org/10.3390/jmse13112042 (registering DOI) - 24 Oct 2025

Abstract

As global Marine resource development continues to expand into deep-sea and ultra-deep-sea domains, the intelligent and green transformation of deep-sea aquaculture equipment has become a key direction for high-quality development of the Marine economy. Large deep-sea cages are considered essential equipment for deep-sea [...] Read more.

As global Marine resource development continues to expand into deep-sea and ultra-deep-sea domains, the intelligent and green transformation of deep-sea aquaculture equipment has become a key direction for high-quality development of the Marine economy. Large deep-sea cages are considered essential equipment for deep-sea aquaculture. However, there are significant challenges associated with ensuring their structural integrity and long-term monitoring capabilities in the complex Marine environments characteristic of deep-sea aquaculture. The present study focuses on large deep-sea cages, addressing their dynamic response challenges and long-term monitoring power supply needs in complex Marine environments. The present study investigates the nonlinear vibration characteristics of flexible net structures under complex fluid loads. To this end, a multi-field coupled dynamic model is constructed to reveal vibration response patterns and instability mechanisms. A self-powered sensing system based on triboelectric nanogenerator (TENG) technology has been developed, featuring a curved surface adaptive TENG array for the real-time monitoring of net vibration states. This review aims to focus on the research of optimizing the design of curved surface adaptive TENG arrays and deep-sea cage monitoring. The present study will investigate the mechanisms of energy transfer and cooperative capture within multi-body coupled cage systems. In addition, the biomechanics of fish–cage flow field interactions and micro-energy capture technologies will be examined. By integrating different disciplinary perspectives and adopting innovative approaches, this work aims to break through key technical bottlenecks, thereby laying the necessary theoretical and technical foundations for optimizing the design and safe operation of large deep-sea cages. Full article

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

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20 pages, 7047 KB

Open AccessArticle

A Simplified Prediction Method for the Hydrodynamic Performance of Ship Propellers Under Heave and Pitch Motions

by Wei Zhang, Guoliang Xu, Siyu Wang and Rui Wu

J. Mar. Sci. Eng. 2025, 13(11), 2041; https://doi.org/10.3390/jmse13112041 (registering DOI) - 24 Oct 2025

Abstract

This paper presents a simplified computational method for evaluating the hydrodynamic performance of a ship propeller, taking into account the effects of wave-induced heave and pitch motions. The method combines Computational Fluid Dynamics (CFD) for propeller hydrodynamic force calculations with forced heave and [...] Read more.

This paper presents a simplified computational method for evaluating the hydrodynamic performance of a ship propeller, taking into account the effects of wave-induced heave and pitch motions. The method combines Computational Fluid Dynamics (CFD) for propeller hydrodynamic force calculations with forced heave and pitch motions computed via the potential flow theory-based method. Numerical simulations at three representative wavelengths demonstrate that heave and pitch motions reduce propeller thrust, increase torque, and decrease the propeller’s efficiency significantly. In addition, the results reveal a nonlinear coupling between heave and pitch effects, where their hydrodynamic contributions are not simply additive. Compared to high-fidelity ship–propeller coupling CFD simulations, the proposed method reduces computational costs by approximately four times while maintaining practical accuracy for wave–propeller interaction analysis. Full article

(This article belongs to the Special Issue Novelties in Marine Propulsion)

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26 pages, 4340 KB

Open AccessArticle

Vertical Motion Stabilization of High-Speed Multihulls in Irregular Seas Using ESO-Based Backstepping Control

by Xianjin Fang, Huayang Li, Zhilin Liu, Guosheng Li, Tianze Ni, Fan Jiang and Jie Zhang

J. Mar. Sci. Eng. 2025, 13(11), 2040; https://doi.org/10.3390/jmse13112040 (registering DOI) - 24 Oct 2025

Abstract

The severe vertical motion of high-speed multihull vessels significantly impairs their seakeeping performance, making the design of effective anti-motion controllers crucial. However, existing controllers, predominantly designed based on deterministic dynamic models, suffer from limitations such as insufficient robustness, reliance on empirical knowledge, structural [...] Read more.

The severe vertical motion of high-speed multihull vessels significantly impairs their seakeeping performance, making the design of effective anti-motion controllers crucial. However, existing controllers, predominantly designed based on deterministic dynamic models, suffer from limitations such as insufficient robustness, reliance on empirical knowledge, structural complexity, and suboptimal performance, which hinder their practical applicability. To address this, this paper proposes a robust decoupled vertical motion controller based on the step response inversion method and incorporating an Extended State Observer (ESO) uncertainty compensation term. The control algorithm is designed leveraging the equivalent noise bandwidth theory to account for the stochastic characteristics of pitch/heave motion, with ESO compensation introduced to enhance robustness. The stability of the closed loop system is rigorously proven through theoretical analysis. Simulation results demonstrate that the proposed algorithm significantly suppresses the amplitudes of both pitch and heave motions. Full article

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

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14 pages, 2944 KB

Open AccessArticle

Calculating the Sediment Flux in Hydrometric Data-Scarce Small Island Coastal Watersheds

by Gaocong Li, Liping Huang, Longbo Deng and Changliang Tong

J. Mar. Sci. Eng. 2025, 13(11), 2039; https://doi.org/10.3390/jmse13112039 (registering DOI) - 24 Oct 2025

Abstract

The information of sediment flux (Q_s) from hydrometric data-scarce small coastal watersheds is an important supplement for interpreting the sedimentary records of continental shelf sedimentary systems. This paper proposes a solution to estimate their values based upon the empirical formula [...] Read more.

The information of sediment flux (Q_s) from hydrometric data-scarce small coastal watersheds is an important supplement for interpreting the sedimentary records of continental shelf sedimentary systems. This paper proposes a solution to estimate their values based upon the empirical formula of small and medium-sized coastal watersheds in adjacent regions, taking the 25 small rivers in Hainan Island as example. Three categories of methods were applied to calculate the Q_s. The first category involves the direct application of global empirical formulas, while the second and third categories utilizes empirical formulas that have been calibrated with regional characteristic data. The Q_s calculation accuracy the above methods was validated by the observed values of typical rivers. Key findings include: (1) The area values of watersheds extracted from SRTM (Shuttle Radar Topography Mission) data exhibit a high correlation with actual values, confirmed the reliability and applicability of SRTM data; (2) The Global equation significantly overestimates Q_s for the validation rivers (average relative error of 18.73), while employing the pristine-modified and disturbed-modified equations effectively improves the calculation accuracy (average relative errors of 0.72 and 1.64, respectively); (3) By averaging the results of different models, the Q_s for the major rivers in Hainan Island was calculated as 6.07 Mt/a before large-scale human activities and 4.56 Mt/a after. This study demonstrates that modification not only needs to be considered to adjust global empirical formulas but also to differentiate between the scenarios of before and after large-scale human activities in small coastal watersheds. Full article

(This article belongs to the Special Issue Coastal Geochemistry: The Processes of Water–Sediment Interaction)

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16 pages, 7510 KB

Open AccessArticle

Experimental Study on Hydrodynamic Characteristics of Streamlined-Layout Double-Row Floating Breakwaters with Wing Plates

by Yu Xu, Yucheng Sui, Jian Zhang, Hao Lin and Zhifeng Wang

J. Mar. Sci. Eng. 2025, 13(11), 2038; https://doi.org/10.3390/jmse13112038 (registering DOI) - 24 Oct 2025

Abstract

Floating breakwater layouts require flexible adjustment to accommodate sheltered area bathymetry. However, most studies have focused solely on straight layouts and have neglected the influence of complex nearshore bathymetry and structures. This work investigates streamlined-layout double-row floating breakwaters with wing plates designed for [...] Read more.

Floating breakwater layouts require flexible adjustment to accommodate sheltered area bathymetry. However, most studies have focused solely on straight layouts and have neglected the influence of complex nearshore bathymetry and structures. This work investigates streamlined-layout double-row floating breakwaters with wing plates designed for a specific port. Wave attenuation performance, motion responses, mooring tensions, and surface wave pressures under realistic nearshore conditions are systematically evaluated through a water tank experiment. The results demonstrate that the wave attenuation performance improves as incident wave height and period decrease, with the attenuation rate increasing by 6.32~11.05%. However, both the motion responses and the uplift pressures on the head and tail modules change slightly. The maximum prototype-scale changes in the maximum amplitudes of surge, heave, and pitch are +0.0625 m, −0.488 m, and +3.8523°, respectively, and the uplift pressures on the head and tail modules exhibit maximum changes of +2.3 kPa and −5.6 kPa, respectively. Additionally, wave reflection induced by nearshore structures influences both harbor tranquility and breakwater motion response. Full article

(This article belongs to the Section Coastal Engineering)

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24 pages, 3544 KB

Open AccessArticle

Preliminary Feasibility Study of Using Hydrogen as a Fuel for an Aquaculture Vessel in Tasmania, Australia

by Hongjun Fan, Peggy Shu-Ling Chen, Andrew Harris, Nagi Abdussamie, Evan Mac A. Gray, Irene Penesis and Javad A. Mehr

J. Mar. Sci. Eng. 2025, 13(11), 2037; https://doi.org/10.3390/jmse13112037 - 24 Oct 2025

Abstract

Decarbonising aquaculture support vessels is pivotal to reducing greenhouse gas (GHG) emissions across both the aquaculture and maritime sectors. This study evaluates the technical and economic feasibility of deploying hydrogen as a marine fuel for a 14.95 m net cleaning vessel (NCV) operating [...] Read more.

Decarbonising aquaculture support vessels is pivotal to reducing greenhouse gas (GHG) emissions across both the aquaculture and maritime sectors. This study evaluates the technical and economic feasibility of deploying hydrogen as a marine fuel for a 14.95 m net cleaning vessel (NCV) operating in Tasmania, Australia. The analysis retains the vessel’s original layout and subdivision to enable a like-for-like comparison between conventional diesel and hydrogen-based systems. Two options are evaluated: (i) replacing both the main propulsion engines and auxiliary generator sets with hydrogen-based systems—either proton exchange membrane fuel cells (PEMFCs) or internal combustion engines (ICEs); and (ii) replacing only the diesel generator sets with hydrogen power systems. The assessment covers system sizing, onboard hydrogen storage integration, operational constraints, lifecycle cost, and GHG abatement. Option (i) is constrained by the sizes and weights of PEMFC systems and hydrogen-fuelled ICEs, rendering full conversion unfeasible within current spatial and technological limits. Option (ii) is technically feasible: sixteen 700 bar cylinders (131.2 kg H₂ total) meet one day of onboard power demand for net-cleaning operations, with bunkering via swap-and-go skids at the berth. The annualised total cost of ownership for the PEMFC systems is 1.98 times that of diesel generator sets, while enabling annual CO₂ reductions of 433 t. The findings provide a practical decarbonisation pathway for small- to medium-sized service vessels in niche maritime sectors such as aquaculture, while clarifying near-term trade-offs between cost and emissions. Full article

(This article belongs to the Special Issue Infrastructure for Offshore Aquaculture Farms)

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19 pages, 7798 KB

Open AccessArticle

A Boundary-Implicit Constraint Reconstruction Method for Solving the Shallow Water Equations

by Dingbing Wei, Jie Yang, Ming Fang and Jianguang Xie

J. Mar. Sci. Eng. 2025, 13(11), 2036; https://doi.org/10.3390/jmse13112036 - 23 Oct 2025

Abstract

To improve the accuracy of second-order cell-centered finite volume method in near-boundary regions for solving the two-dimensional shallow water equations, a numerical scheme with globally second-order accuracy was proposed. Having the primary objective to overcome the challenge of accuracy degradation in near-boundary regions [...] Read more.

To improve the accuracy of second-order cell-centered finite volume method in near-boundary regions for solving the two-dimensional shallow water equations, a numerical scheme with globally second-order accuracy was proposed. Having the primary objective to overcome the challenge of accuracy degradation in near-boundary regions and to develop a robust numerical framework combining high-order accuracy with strict conservation, the key research objectives had been as follows: Firstly, a physical variable reconstruction method combining a vertex-based nonlinear weighted reconstruction scheme and a monotonic upwind total variation diminishing scheme for conservation laws was proposed. While the overall computational efficiency was maintained, linear-exact reconstruction in near-boundary regions was achieved. The variable reconstruction in interior regions was integrated to achieve global second-order accuracy. Subsequently, a flux boundary condition treatment method based on uniform flow was proposed. Conservative allocation of hydraulic parameters was achieved, and flow stability in inflow regions was enhanced. Finally, a series of numerical test cases were provided to validate the performance of the proposed method in solving the shallow water equations in terms of high-order accuracy, exact conservation properties, and shock-capturing capabilities. The superiority of the method was further demonstrated under high-speed flow conditions. The high-precision numerical model developed in this study holds significant value for enhancing the predictive capability of simulations for natural disasters such as flood propagation and tsunami warning. Its robust boundary treatment methods also provide a reliable tool for simulating free-surface flows in complex environments, offering broad prospects for engineering applications. Full article

(This article belongs to the Section Ocean Engineering)

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18 pages, 3538 KB

Open AccessArticle

Deep Learning-Assisted ES-EKF for Surface AUV Navigation with SINS/GPS/DVL Integration

by Yuanbo Yang, Bo Xu, Baodong Ye and Feimo Li

J. Mar. Sci. Eng. 2025, 13(11), 2035; https://doi.org/10.3390/jmse13112035 - 23 Oct 2025

Abstract

This study presents a deep learning–assisted integrated navigation scheme implemented on an autonomous underwater vehicle carrying a Chinese domestically developed strapdown inertial navigation system, designed for operation in surface and littoral environments. The system integrates measurements from SINS, the global positioning system, and [...] Read more.

This study presents a deep learning–assisted integrated navigation scheme implemented on an autonomous underwater vehicle carrying a Chinese domestically developed strapdown inertial navigation system, designed for operation in surface and littoral environments. The system integrates measurements from SINS, the global positioning system, and a Doppler velocity log, while integrating a Decoder-based covariance estimator into the error state-extended Kalman filter. This hybrid architecture adaptively models time-varying processes and measurement noise from raw sensor inputs, greatly improving robustness for surface navigation in dynamic marine environments. To improve learning efficiency, we design a compact and informative feature representation that can be adapted to navigation error dynamics. The novel structure captures temporal dependencies and the evolution of nonlinear error more effectively than typical sequence models, achieving faster convergence and superior accuracy compared to GRU and Transformer baselines. The experimental results based on real sea trial data show that our method significantly outperforms model-based and learning-based methods in terms of navigation solution accuracy and stability, and the adaptive estimation of noise covariance. Specifically, it achieves the lowest RMSE of 0.0274, reducing errors by 94.6–34.6%, compared to conventional ES-EKF-integrated navigation, Transformer, GRU, and a DCE variant. These findings underscore the practical significance of integrating domain-informed filtering methodologies with deep noise modeling frameworks to achieve robust and accurate AUV surface navigation. Full article

(This article belongs to the Section Ocean Engineering)

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14 pages, 501 KB

Open AccessArticle

Two-Dimensional Thompson Sampling for Joint Beam and Power Control for Uplink Maritime Communications

by Kyeong Jea Lee, Joo-Hyun Jo, Sungyoon Cho, Ki-Won Kwon and DongKu Kim

J. Mar. Sci. Eng. 2025, 13(11), 2034; https://doi.org/10.3390/jmse13112034 - 23 Oct 2025

Abstract

In a cellular maritime communication system, ocean buoys are essential to enable environmental monitoring, offshore platform management, and disaster response. Therefore, energy-efficient transmission from the buoys is a key requirement to prolong their operational time. A fixed uplink beamforming can be considered to [...] Read more.

In a cellular maritime communication system, ocean buoys are essential to enable environmental monitoring, offshore platform management, and disaster response. Therefore, energy-efficient transmission from the buoys is a key requirement to prolong their operational time. A fixed uplink beamforming can be considered to save energy by leveraging its beam gain while managing the target link reliability. However, the dynamic condition of ocean waves causes buoys’ random orientation, leading to frequent misalignment of their predefined beam direction aimed at the base station, which degrades both the link reliability and energy efficiency. To address this challenge, we propose a wave-adaptive beamforming framework to satisfy data-rate demands within limited power budgets. This strategy targets scenarios where sea state information is unavailable, such as in network-assisted systems. We propose a Two-Dimensional Thompson Sampling (2DTS) scheme that jointly selects beamwidth and transmit power to satisfy the target-rate constraint with minimal power consumption and thus achieve maximal energy efficiency. This adaptive learning approach effectively balances exploration and exploitation, enabling efficient operation in uncertain and changing sea conditions. In simulation, under a moderate sea state, 2DTS achieves an energy efficiency of

1.26 \times 10^{4}

bps/Hz/J at round 600, which is

73.7 %

of the ideal (

1.71 \times 10^{4}

), and yield gains of

96.9 %

and

447.8 %

over exploration-based TS and conventional TS, respectively. Under a harsh sea state, 2DTS attains

3.09 \times 10^{4}

bps/Hz/J (

85.6 %

of the ideal

3.61 \times 10^{4}

), outperforming the exploration-based and conventional TS by

83.9 %

and

113.1 %

, respectively. The simulation results demonstrate that the strategy enhances energy efficiency, confirming its practicality for maritime communication systems constrained by limited power budgets. Full article

(This article belongs to the Special Issue Sustainable and Efficient Maritime Operations)

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8 pages, 1069 KB

Open AccessReview

Effect of Temperature on Filtration in the Blue Mussel, Mytilus edulis—Our Present Understanding

by Hans Ulrik Riisgård and Poul S. Larsen

J. Mar. Sci. Eng. 2025, 13(11), 2033; https://doi.org/10.3390/jmse13112033 - 23 Oct 2025

Abstract

The effect of temperature on the filtration rate of filter-feeding bivalves is controversial. Some studies show a clear increase in filtration with an increase in temperature, in agreement with a decrease in kinematic viscosity with increasing temperature and a simultaneous increase in beat [...] Read more.

The effect of temperature on the filtration rate of filter-feeding bivalves is controversial. Some studies show a clear increase in filtration with an increase in temperature, in agreement with a decrease in kinematic viscosity with increasing temperature and a simultaneous increase in beat frequency of the water-pumping lateral cilia. However, other studies show little or no effect. Here, we present our understanding of the effect of temperature on the filtration rate of the blue mussel, Mytilus edulis, primarily based on our own previously published experimental studies. We point out the possible pitfalls associated with findings of little or no such effects, most likely caused by erroneous use of the method for measuring the filtration rate and failure to separate the factors that may affect it, e.g., the temperature-tolerance interval and the algal-concentration interval within which the mussel is optimally filtering at a specified temperature. Full article

(This article belongs to the Section Marine Biology)

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25 pages, 3706 KB

Open AccessArticle

Suction-Driven Installation of a 20 m-Diameter Circular Steel Cofferdam: A Full-Scale Field Test in Jebudo, Republic of Korea

by Ju-Hyung Lee, Zhen-Hua Xin and Seongho Hong

J. Mar. Sci. Eng. 2025, 13(11), 2032; https://doi.org/10.3390/jmse13112032 - 23 Oct 2025

Abstract

Cofferdams provide dry, stable working conditions for construction in marine environments. However, conventional methods often require significant time and cost for installation and removal, and are prone to leakage. This study proposes a novel method for the rapid and efficient construction of a [...] Read more.

Cofferdams provide dry, stable working conditions for construction in marine environments. However, conventional methods often require significant time and cost for installation and removal, and are prone to leakage. This study proposes a novel method for the rapid and efficient construction of a large-diameter circular cofferdam using suction-driven installation and extraction. As opposed to conventional suction bucket foundations, the upper part of the cofferdam remains exposed above the water surface, and several prefabricated segments are assembled to form a single suction unit. A full-scale field test was conducted in Jebudo, Republic of Korea, using a 20 m-diameter, 13 m-high circular steel cofferdam. The test program included the design and fabrication of a suction cover and an optimized piping system. The key measurements during installation included the suction pressure variation with the penetration depth, leakage at the segmental joints, structural deformations, and inclination. The cofferdam successfully penetrated to a target embedment depth of 5 m at an average rate of 1.83 m/h and was safely removed using reverse suction. Although suction technology has been widely applied to offshore foundations and anchors, this study is the first to demonstrate its feasibility for large cofferdams. These results provide a foundation for future offshore applications of suction-driven cofferdam installations. Full article

(This article belongs to the Section Ocean Engineering)

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21 pages, 14327 KB

Open AccessArticle

Numerical Modeling of Wave Hydrodynamics Around Submerged Artificial Reefs on Fringing Reefs in Weizhou Island of Northern South China Sea

by Zuodong Liang, Guangxian Huang, Wen Huang, Hailun Chen, Kefu Yu and Dong-Sheng Jeng

J. Mar. Sci. Eng. 2025, 13(11), 2031; https://doi.org/10.3390/jmse13112031 - 23 Oct 2025

Abstract

This study numerically investigates wave transformation and setup processes across fringing reefs, focusing on artificial reef configuration effects under varying tidal conditions and incident wave parameters. The OpenFOAM-based waves2Foam model simulates hydrodynamic processes along reef profiles containing a fore-reef slope and reef flat. [...] Read more.

This study numerically investigates wave transformation and setup processes across fringing reefs, focusing on artificial reef configuration effects under varying tidal conditions and incident wave parameters. The OpenFOAM-based waves2Foam model simulates hydrodynamic processes along reef profiles containing a fore-reef slope and reef flat. Following validation against laboratory data, the model simulates cross-shore wave height attenuation and setup within fringing reef systems. The results demonstrate that reef flat water depth substantially modulates wave dynamics: during low tide, intensified wave breaking elevates the maximum wave height and setup by up to 45.7% and 78.5%, respectively, compared to high-tide conditions. Furthermore, this water depth critically governs the reef configuration’s influence on wave energy dissipation efficiency. Under high tide, additional reef rows increase the peak wave height by 5.2% while reducing wave setup by 10.5%. In contrast, expanded reef spacing reduces the peak wave height by 2.1% and decreases the peak wave setup by 2.4%. The temporal evolution of wave reflection (

K_{R}

) and transmission (

K_{T}

) coefficients reveals that shallow-water conditions amplify wave reflection while diminishing transmission capacity, as tidal variations directly regulate wave propagation mechanisms through water depth modulation. At the outer reef flat boundary,

K_{R}

and

K_{T}

values for existing artificial reefs exhibit variations below 5% across all tidal phases, row configurations, and spacing combinations. Consequently, current reef structures provide limited control over wave transmission in fringing reef terrains, indicating that structural modifications such as increasing reef elevation or deploying reefs on the fore-reef slope could enhance attenuation performance. Full article

(This article belongs to the Section Ocean Engineering)

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27 pages, 13030 KB

Open AccessArticle

Hybrid Log-Mel and HPSS-Aided Convolutional Neural Network for Underwater Very-Low-Frequency Remote Passive Sonar Detection

by Haitao Dong, Lijian Yang, Yuan Liu and Siyuan Li

J. Mar. Sci. Eng. 2025, 13(11), 2030; https://doi.org/10.3390/jmse13112030 - 23 Oct 2025

Abstract

Very-low-frequency (VLF) passive sonar detection is one of the core technologies for maritime surveillance, although its performance is often severely affected by strong impulsive ocean ambient noise interference. This paper, for the first time, proposes a convolutional neural network (CNN) detection framework with [...] Read more.

Very-low-frequency (VLF) passive sonar detection is one of the core technologies for maritime surveillance, although its performance is often severely affected by strong impulsive ocean ambient noise interference. This paper, for the first time, proposes a convolutional neural network (CNN) detection framework with hybrid Log-Mel spectrogram (Log-Mel) and Harmonic–Percussive Source Separation (HPSS) preprocessing. Aiming to highlight the detailed features of low frequencies in accordance with impulsive noise interference removal, the network was trained on a measured dataset in the South China Sea for a whole week by maximize the area under receiver operating characteristic curve (AUC) that corresponds to a false alarm probability of less than 0.1. The test results show that compared with a typical Short-Time Fourier Transform (STFT) input feature, the utilization of Log-Mel and HPSS can be superior, especially utilizing Log-Mel and HPSS(H) features at the same time. Validation with a set of measured moving ship data shows that the detection performance of the proposed hybrid Log-Mel and HPSS-aided CNN can be stable and significantly improve the remote passive sonar detection performance. Full article

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

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20 pages, 17509 KB

Open AccessArticle

Underwater Structural Multi-Defects Automatic Detection via Hybrid Neural Network

by Chunyan Ma, Zhe Chen, Huibin Wang and Guangze Shen

J. Mar. Sci. Eng. 2025, 13(11), 2029; https://doi.org/10.3390/jmse13112029 - 22 Oct 2025

Abstract

Detecting underwater structural defects is vital for hydraulic engineering safety. Diverse patterns of underwater structural defects, i.e., the morphology and scale characteristics, pose difficulties on feature representability during detection. Any single feature morphology is insufficient to fully characterize diverse types of underwater defect [...] Read more.

Detecting underwater structural defects is vital for hydraulic engineering safety. Diverse patterns of underwater structural defects, i.e., the morphology and scale characteristics, pose difficulties on feature representability during detection. Any single feature morphology is insufficient to fully characterize diverse types of underwater defect patterns. This paper proposes a novel hybrid neural network to enhance feature representation of underwater structural multi-defects, which in turn improves the accuracy and adaptability of underwater detection. Three types of convolution operations are combined to build Hybrid Aggregation Network (HanNet), enhancing the morphological representation for diverse defects. Considering the scale difference of diverse defects, the Multi-Scale Shared Feature Pyramid (MSFP) is proposed, facilitating adaptive representation for diverse sizes of structural defects. The defect detection module leverages an Adaptive Spatial-Aware Attention (ASAA) at the backend, enabling selective enhancement of salient defect features. For model training and evaluation, we, for the first time, build an underwater structural multi-defects sonar image dataset containing a wide range of typical defect types. Experimental results demonstrate that the proposed model outperforms state-of-the-art methods, significantly improving defect detection accuracy, and provides an effective solution for detecting diverse structural defects in complex underwater environments. Full article

(This article belongs to the Section Ocean Engineering)

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26 pages, 6810 KB

Open AccessArticle

Numerical Simulation Study of Wear in a Segmented-Blade Helical Centrifugal Deep-Sea Mining Pump

by Hao Lv, Tao Yu, Ibra Fall, Desheng Zhang and Ruijie Zhao

J. Mar. Sci. Eng. 2025, 13(11), 2028; https://doi.org/10.3390/jmse13112028 - 22 Oct 2025

Abstract

The deep-sea mining pump is a core component in deep-sea mineral resource extraction, whose performance directly determines the transportation efficiency of coarse-grained ore and overall system reliability. However, deep-sea mining pumps suffer from severe abrasion of internal components due to continuous impact by [...] Read more.

The deep-sea mining pump is a core component in deep-sea mineral resource extraction, whose performance directly determines the transportation efficiency of coarse-grained ore and overall system reliability. However, deep-sea mining pumps suffer from severe abrasion of internal components due to continuous impact by coarse ore particles, leading to short service life and high maintenance costs. These issues adversely impact the economics and continuity of mining operations. Consequently, studying the solid-liquid flow to understand wear mechanisms and develop optimized, wear-resistant designs is crucial for enhancing pump performance. This paper establishes a fully coupled solid-liquid two-phase flow platform by integrating Fluent and EDEM, based on an artificial diffusion-based coarse-particle CFD-DEM (Computational Fluid Dynamics-Discrete Element Method) approach, to systematically investigate the critical technical issue of internal pump wear. The study finds that wear in traditional spiral centrifugal pump blades is primarily concentrated on the leading edge and the middle section. On the leading edge, wear comprises 56.4% cutting wear and 44.7% impact wear; in contrast, cutting wear accounts for 96.8% of the total wear in the middle section. To address the premature failure of traditional impeller blades caused by localized wear concentration, this paper proposes an optimized design for a novel spiral centrifugal impeller with segmented blades. By modifying the impeller structure, the proposed design relocates the primary wear zones to the leading edges of the two blade segments, thereby facilitating the application of anti-wear treatments. Full article

(This article belongs to the Section Ocean Engineering)

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22 pages, 3177 KB

Open AccessArticle

RECAD: Retinex-Based Efficient Channel Attention with Dark Area Detection for Underwater Images Enhancement

by Tianchi Zhang, Qiang Liu, Hongwei Qin and Xing Liu

J. Mar. Sci. Eng. 2025, 13(11), 2027; https://doi.org/10.3390/jmse13112027 - 22 Oct 2025

Abstract

Focusing on visual target detection for Autonomous Underwater Vehicles (AUVs), this paper investigates enhancement methods for weakly illuminated underwater images, which typically suffer from blurring, color distortion, and non-uniform illumination. Although deep learning-based approaches have received considerable attention, existing methods still face limitations [...] Read more.

Focusing on visual target detection for Autonomous Underwater Vehicles (AUVs), this paper investigates enhancement methods for weakly illuminated underwater images, which typically suffer from blurring, color distortion, and non-uniform illumination. Although deep learning-based approaches have received considerable attention, existing methods still face limitations such as insufficient feature extraction, poor detail detection, and high computational costs. To address these issues, we propose RECAD—a lightweight and efficient underwater image enhancement method based on Retinex theory. The approach incorporates a dark region detection mechanism to significantly improve feature extraction from low-light areas, along with an efficient channel attention module to reduce computational complexity. A residual learning strategy is adopted in the image reconstruction stage to effectively preserve structural consistency, achieving an SSIM value of 0.91. Extensive experiments on the UIEB and LSUI benchmark datasets demonstrate that RECAD outperforms state-of-the-art models including FUnIEGAN and U-Transformer, achieving a high SSIM of 0.91 and competitive UIQM scores (up to 3.19), while improving PSNR by 3.77 dB and 0.69–1.09 dB, respectively, and attaining a leading inference speed of 97 FPS, all while using only 0.42 M parameters, which substantially reduces computational resource consumption. Full article

(This article belongs to the Section Ocean Engineering)

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21 pages, 10644 KB

Open AccessArticle

Structural Response Research for a Submarine Power Cable with Corrosion-Damaged Tensile Armor Layers Under Pure Tension

by Weidong Ruan, Chengcheng Zhou, Erjian Qiu, Xu Zheng, Zhaohui Shang, Pan Fang and Yong Bai

J. Mar. Sci. Eng. 2025, 13(11), 2026; https://doi.org/10.3390/jmse13112026 - 22 Oct 2025

Abstract

Submarine power cables (SPCs), as critical infrastructure for offshore wind farms, are the primary conduits for transmitting electricity from turbines to the grid. Actions such as seabed friction can cause damage to the submarine power cable’s outer sheath, accelerating the penetration of seawater [...] Read more.

Submarine power cables (SPCs), as critical infrastructure for offshore wind farms, are the primary conduits for transmitting electricity from turbines to the grid. Actions such as seabed friction can cause damage to the submarine power cable’s outer sheath, accelerating the penetration of seawater corrosion media. This subsequently leads to corrosion fatigue or excessive loading in the tensile armor layer, which seriously threatens the long-term operational reliability of SPCs and the security of energy transmission. Based on homogenization theory and periodic boundary conditions, a repetitive unit cell (RUC) ABAQUS finite element model for a single-core submarine power cable (SPC) was established in this paper. And the mechanical response of the single-core SPC with the corroded tensile armor layers under tensile loading condition were systematically investigated. By comparing with a full-scale model, the feasibility and accuracy of the cable RUC damaged model proposed in this paper were effectively verified. It was found that the RUC damaged model exhibits significant stress concentration phenomena due to localized corrosion damage in the tensile armor layers, with its maximum von Mises stress being considerably higher than that of the RUC intact model; the elastic tensile stiffness of the SPC continuously decreases with increasing corrosion damage depth, but the magnitude of this reduction is small. This is because the corroded region is relatively small compared to the entire cable model dimension. This research reveals the potential impact of localized corrosion on the mechanical performance of the tensile armor layer, which can hold significant engineering importance for assessing the remaining load-bearing capacity of in-service SPCs and ensuring the reliability of subsea energy transmission corridors. Full article

(This article belongs to the Special Issue Marine Cable Technology: Cutting-Edge Research and Development Trends)

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22 pages, 4949 KB

Open AccessArticle

The Effect of Wind–Wave Correlations on the Optimal Thruster Location for Offshore Vessels

by Francesco Mauro and Giada Kyaw’oo D’Amore

J. Mar. Sci. Eng. 2025, 13(11), 2025; https://doi.org/10.3390/jmse13112025 - 22 Oct 2025

Abstract

Offshore vessels are nowadays equipped with dynamic positioning systems, meaning they have additional thrusters dedicated to the station keeping of the unit. However, there is no rational criterion on the placement of these devices to increment station keeping capabilities. This is true both [...] Read more.

Offshore vessels are nowadays equipped with dynamic positioning systems, meaning they have additional thrusters dedicated to the station keeping of the unit. However, there is no rational criterion on the placement of these devices to increment station keeping capabilities. This is true both in case of a vessel retrofitting or for the design of a new unit. The present work proposes investigating a methodology for the optimal placement of thrusters along the hull of an offshore unit. This implies the adoption of a suitable optimisation algorithm capable of handling all the constraints of the optimisation problem. As the target is the optimal capability, the optimisation should handle multiple dynamic positioning capability calculations, meaning (in a quasi-static approach) that it is capable of solving multiple thrust allocation problems at each optimisation step. As thruster allocation is another optimisation problem, the process should handle two nested optimisations. Here, the global location problem is solved with a differential evolution algorithm, while the thrust allocation employs non-linear programming. As the capability calculations imply the adoption of a specific wind–wave correlation, the present work compares the effect of different correlations on the optimised location of the thrusters. The results presented on a reference Pipe Lay Crane Vessel highlight the differences in the final optimum as a function of the environmental modelling. Full article

(This article belongs to the Special Issue Design Optimisation in Marine Engineering)

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28 pages, 5040 KB

Open AccessReview

Distributional Range Shifts Caused by Glacial–Interglacial Cycles: A Review on Timing, Main Processes, and Patterns of Late Pleistocene Marine Dispersal by Invertebrates in the NE Atlantic

by Sérgio P. Ávila

J. Mar. Sci. Eng. 2025, 13(11), 2024; https://doi.org/10.3390/jmse13112024 - 22 Oct 2025

Abstract

The fossil record of marine molluscs has been used as evidence to test marine island biogeography theories and to complement the evolutionary patterns of biodiversity and endemicity found in oceanic islands and archipelagos. Although long-distance dispersal patterns have been the subject of several [...] Read more.

The fossil record of marine molluscs has been used as evidence to test marine island biogeography theories and to complement the evolutionary patterns of biodiversity and endemicity found in oceanic islands and archipelagos. Although long-distance dispersal patterns have been the subject of several studies, important questions may still be posed. For instance, are these processes random, or do they show distinct patterns? And are they restricted to “windows of opportunities”, or do they occur continuously? In the NE Atlantic, the dispersal of tropical species towards higher latitudes associated with the last interglacial period is a well-known phenomenon. However, the most probable dispersal route remains a matter of debate. To test these ideas, we used the Atlantic and Mediterranean last interglacial fossil records, and compared the present geographic distribution of shallow-water marine molluscs with that registered during the last interglacial episode, aiming to detect changes. Our results show that 27 species became extinct during the course of the last glacial episode, and that 55 marine mollusc species (43 gastropods and 12 bivalves) are ecostratigraphic indicators for the MIS 5e fossiliferous deposits in the Macaronesian archipelagos, the Atlantic coasts of Morocco, and the Mediterranean. Finally, we provide arguments for the timing of dispersal, which occurred during a restricted “window of opportunity” associated with the inception of the last interglacial, and for the most probable route of dispersal of the tropical species, most of them denoting a Cabo Verdean origin. Full article

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

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