Journal of Marine Science and Engineering

31 pages, 2985 KiB

Open AccessArticle

Hydrodynamic Performance Assessment of Emerged, Alternatively Submerged and Submerged Semicircular Breakwater: An Experimental and Computational Study

by Faris Ali Hamood Al-Towayti, Hee-Min Teh, Zhe Ma, Idris Ahmed Jae, Agusril Syamsir and Ebrahim Hamid Hussein Al-Qadami

J. Mar. Sci. Eng. 2024, 12(7), 1105; https://doi.org/10.3390/jmse12071105 (registering DOI) - 29 Jun 2024

Abstract

Coastal protection structures are essential defenses against wave energy, safeguarding coastal communities. This study aims to refine coastal protection strategies by employing a semicircular breakwater (SBW) model. Through a combination of physical and computational models, the hydrodynamic properties of the SBW under regular [...] Read more.

Coastal protection structures are essential defenses against wave energy, safeguarding coastal communities. This study aims to refine coastal protection strategies by employing a semicircular breakwater (SBW) model. Through a combination of physical and computational models, the hydrodynamic properties of the SBW under regular wave conditions were thoroughly examined. The primary objectives included delineating the hydrodynamic characteristics of SBWs, developing a computational model to validate experimental findings. Hydrodynamic characteristics of the SBW model were scrutinized across various wave conditions. Experimental testing in a wave flume covered a range of relative water depths (d/h) from 0.667 to 1.667, wave steepness (H_i/L) spanning 0.02 to 0.06 and wave periods ranging from 0.8 to 2.5 s. Notably, analysis of an emerged SBW with d/h = 0.667 revealed superior wave reflection, while an alternative submerged SBW with d/h = 1.000 showed the highest energy loss. These findings are further corroborated by the validation of computational models against experimental outcomes for d/h = 0.667, 1.000, 1.333 and 1.667. Moreover, the investigation of forces revealed an inverse correlation between horizontal forces and wave height, while vertical forces showed nuanced variations, including a slightly decreasing average vertical force with greater relative wave period (B/L) for different immersion scenarios. Full article

(This article belongs to the Section Coastal Engineering)

3 pages, 142 KiB

Open AccessEditorial

Advanced Research on the Sustainable Maritime Transportation

by Xianhua Wu, Jian Wu and Lang Xu

J. Mar. Sci. Eng. 2024, 12(7), 1104; https://doi.org/10.3390/jmse12071104 (registering DOI) - 29 Jun 2024

Abstract

With globalization and environmental sustainability growing in importance, the sustainable development of maritime transportation, as the main mode of international trade, is particularly significant [...] Full article

(This article belongs to the Special Issue Advanced Research on the Sustainable Maritime Transportation)

20 pages, 1048 KiB

Open AccessArticle

Container Yard Layout Design Problem with an Underground Logistics System

by Bin Lu, Mengxia Zhang, Xiaojie Xu, Chengji Liang, Yu Wang and Hongchen Liu

J. Mar. Sci. Eng. 2024, 12(7), 1103; https://doi.org/10.3390/jmse12071103 (registering DOI) - 28 Jun 2024

Abstract

In recent years, underground logistics systems have attracted more and more attention from scholars and are considered to be a promising new green and intelligent transportation mode. This paper proposes a yard design problem considering an underground container logistics system. The structure and [...] Read more.

In recent years, underground logistics systems have attracted more and more attention from scholars and are considered to be a promising new green and intelligent transportation mode. This paper proposes a yard design problem considering an underground container logistics system. The structure and workflow of the underground container logistics system are analyzed, and key features are recognized for the yard design problem, such as the container block layout direction, the lane configuration in the yard, and the number of container blocks. We formulate the problem into mathematical models under different scenarios of the key features with the comprehensive objective of maximizing the total throughput and minimizing the total operation cost simultaneously. An improved tabu search algorithm is designed to solve the problem. Experimental results show that the proposed algorithm can generate a satisfactory layout design solution for a real-size instance. Our research studies different container yard design options for introducing the underground logistics system into port terminals, which provides an important scientific foundation for promoting the application of underground container logistics systems. Full article

(This article belongs to the Section Ocean Engineering)

18 pages, 1637 KiB

Open AccessArticle

A Novel Method for Analyzing Sandbar Distribution in Shelf-Type Tidal Deltas Using Sediment Dynamic Simulation

by Mingming Tang, Sichen Xiong, Qian Zhang, Ruifeng Hong, Chenyang Peng and Rong Xie

J. Mar. Sci. Eng. 2024, 12(7), 1102; https://doi.org/10.3390/jmse12071102 (registering DOI) - 28 Jun 2024

Abstract

Shallow marine shelf sedimentation is a hot and difficult topic in today’s reservoir sedimentology research, and it is widely present in the world. The shallow marine shelf sedimentation is not only affected by complex hydrodynamic effects such as tides and waves, but also [...] Read more.

Shallow marine shelf sedimentation is a hot and difficult topic in today’s reservoir sedimentology research, and it is widely present in the world. The shallow marine shelf sedimentation is not only affected by complex hydrodynamic effects such as tides and waves, but also controlled by bottom tectonic features, forming a complex and varied sedimentation pattern. During the Middle Jurassic period, the northern part of West Siberian Basin was characterized by a shallow marine shelf sedimentary environment. In the central reion of this basin, a typical tectonic uplift zone developed, forming a tectonic background of “one uplift zone between two depressions”. Simultaneously, the dominant influence of tides in the shallow marine shelf environment facilitated the formation of a typical shelf-type tidal delta sedimentation system in the Jurassic strata of the northern part of West Siberian Basin. This sedimentation constitutes a significant natural gas reservoir, and it is important to investigate the sedimentary evolution of shelf-type tidal deltas and to clarify the internal structure and distribution of sedimentary sand bodies and interlayers in shelf-type tidal deltas, which is the basis for the fine development of this type of reservoir. This paper takes the Jurassic strata in the Y region of northern part of West Siberian Basin as the research object, and conducts numerical simulation based on sedimentary dynamics for the shelf-type tidal delta sedimentation formed under the tectonic background of “one uplift zone between two depressions”. In addition, tidal amplitude and initial water level were selected for different hydrodynamic factors to study the main controlling factors of shelf-type tidal delta sedimentation. The simulation results show that tidal amplitude is positively correlated with three-dimensional configuration characteristic parameters of the sedimentary sand bodies, and the development of tidal bars becomes more and more limited as the initial water level increases. This paper systematically investigates the sedimentary evolution of shelf-type tidal delta under the tectonic background of “one uplift zone between two depressions” by the sedimentary dynamics method, which deepens the understanding of the shelf-type tidal delta sedimentation process and provides a new thinking for the development of this sedimentary reservoir type (School of Geosciences China University of Petroleum (East China)). Full article

(This article belongs to the Special Issue High-Efficient Exploration and Development of Oil & Gas from Ocean—2nd Edition)

26 pages, 5443 KiB

Open AccessArticle

Analysis of Horizontal Cylinder Load under Different Conditions in Regards to Waves and Flows

by Xiaoguo Zhou, Qingdian Jiang, Kai Wang and Shuqi Wang

J. Mar. Sci. Eng. 2024, 12(7), 1101; https://doi.org/10.3390/jmse12071101 (registering DOI) - 28 Jun 2024

Abstract

A numerical simulation based on the CFD method is used to study the interaction between a horizontal cylinder and wave flow. Firstly, a two-dimensional numerical calculation model of both a fixed and a rigid moving cylinder, with a free surface under varying wave [...] Read more.

A numerical simulation based on the CFD method is used to study the interaction between a horizontal cylinder and wave flow. Firstly, a two-dimensional numerical calculation model of both a fixed and a rigid moving cylinder, with a free surface under varying wave flow conditions, is created. In the established model, the loads on the horizontal cylinder under different submergence depths, flow velocities, cylinder sizes, wave periods, and k values (spring stiffness) are analyzed and calculated. The results show that, when the cylinder is close to the free surface, its hydrodynamic load under wave flow conditions is more sensitive to changes in submergence depth, which essentially affects wave reflection and blockage. At different flow velocities, k values, cylinder radii, and arm lengths, the main frequency of the Fourier transform of the cylinder motion curve remains unchanged; however, the main frequency does change with the wave period and submergence depth. The efficiency of rotary cylindrical energy harvesting is influenced by various factors, among which an initial increase and then decrease are observed with a gradually increasing k value, arm length, period, and radius, in addition to an observed decrease with increasing flow velocity. Full article

(This article belongs to the Special Issue Advances in Marine Engineering Hydrodynamics)

18 pages, 6393 KiB

Open AccessArticle

Design and Experimental Research of a Lifting-Type Tidal Energy Capture Device

by Lingjie Bao, Ying Wang, Hao Li, Junhua Chen, Fangping Huang and Chuhua Jiang

J. Mar. Sci. Eng. 2024, 12(7), 1100; https://doi.org/10.3390/jmse12071100 (registering DOI) - 28 Jun 2024

Abstract

In this study, in order to promote the development of far-reaching marine aquaculture equipment in an intelligent direction and solve the problems related to power supply, a tidal current energy harvesting device for a low-velocity sea area is proposed. For low-velocity waters in [...] Read more.

In this study, in order to promote the development of far-reaching marine aquaculture equipment in an intelligent direction and solve the problems related to power supply, a tidal current energy harvesting device for a low-velocity sea area is proposed. For low-velocity waters in farming areas, the device can effectively harness tidal energy to provide a stable power supply to open sea cages. A mathematical model of the Savonius turbine blade is established, and the influence of the distance between the impeller center and the water surface on the energy capture efficiency of the turbine is analyzed through numerical simulation. Using ANSYS2021R1 software, the velocity field of the floating body is simulated, and the overall structure and anchoring system of the power generation device is designed. In order to verify the effectiveness of the power generation device, a test model is built and a physical model test is carried out. The variation in parameters related to the relative distance between the impeller and the water under different flow velocities is tested, and the test data are analyzed. The test results show that the floating body can increase the flow speed by 10%. Optimizing the blade number and order of the S-turbine can capture more than 20% of the energy. Under different flow velocities, the capture power of the impeller first increases and then decreases with increasing distance from the water. When the center of the impeller is one-quarter of the impeller diameter higher than the water surface, the output power of the impeller is at the maximum. This indicates that the proposed power generation device can effectively use tidal energy under different water depth conditions and provide a stable power supply for far-reaching marine aquaculture equipment. Full article

(This article belongs to the Section Marine Energy)

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11 pages, 517 KiB

Open AccessArticle

Prediction of Pile Running during Installation Using Deep Learning Method

by Ben He, Ruilong Shi, Qingzheng Guan and Yitao Yang

J. Mar. Sci. Eng. 2024, 12(7), 1099; https://doi.org/10.3390/jmse12071099 (registering DOI) - 28 Jun 2024

Viewed by 51

Abstract

Pile running during the installation of offshore large diameter pipe piles poses a significant challenge to construction safety and pile bearing capacity. This paper proposes a deep learning (DL)-based method for predicting pile running occurrences. Utilizing a dataset of pile installation records collected [...] Read more.

Pile running during the installation of offshore large diameter pipe piles poses a significant challenge to construction safety and pile bearing capacity. This paper proposes a deep learning (DL)-based method for predicting pile running occurrences. Utilizing a dataset of pile installation records collected from various construction sites, the DL model was trained and tested. The predictive capacity of the DL model was compared with conventional analytical methods, demonstrating its superior performance in terms of accuracy and robustness. Additionally, the SHAP (SHapley Additive exPlanations) method was employed for the sensitivity analysis of the model’s input variables, and the resultant importance ranking agreed well with the findings of existing studies, thus enhancing the reliability and interpretability of the model’s predictions. Full article

(This article belongs to the Section Ocean Engineering)

25 pages, 13461 KiB

Open AccessArticle

A Ship Energy Consumption Prediction Method Based on TGMA Model and Feature Selection

by Yuhang Liu, Kai Wang, Yong Lu, Yongfeng Zhang, Zhongwei Li, Ranqi Ma and Lianzhong Huang

J. Mar. Sci. Eng. 2024, 12(7), 1098; https://doi.org/10.3390/jmse12071098 (registering DOI) - 28 Jun 2024

Viewed by 61

Abstract

Optimizing ship energy efficiency is a crucial measure for reducing fuel use and emissions in the shipping industry. Accurate prediction models of ship energy consumption are essential for achieving this optimization. However, external factors affecting ship fuel consumption have not been comprehensively investigated, [...] Read more.

Optimizing ship energy efficiency is a crucial measure for reducing fuel use and emissions in the shipping industry. Accurate prediction models of ship energy consumption are essential for achieving this optimization. However, external factors affecting ship fuel consumption have not been comprehensively investigated, and many existing studies still face efficiency and accuracy challenges. In this study, we propose a neural network model called TCN-GRU-MHSA (TGMA), which incorporates the temporal convolutional network (TCN), the gated recurrent unit (GRU), and multi-head self-attention mechanisms to predict ship energy consumption. Firstly, the characteristics of ship operation data are analyzed, and appropriate input features are selected. Then, the prediction model is established and validated through application analysis. Using the proposed model, the prediction accuracy of ship energy consumption can reach up to 96.04%. Comparative analysis results show that the TGMA model outperforms existing models, including those based on LSTM, GRU, SVR, TCN-GRU, and BP neural networks, in terms of accuracy. Therefore, the developed model can effectively predict ship fuel usage under various conditions, making it essential for optimizing and improving ship energy efficiency. Full article

(This article belongs to the Section Marine Pollution)

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19 pages, 938 KiB

Open AccessArticle

Assessing the On-Board Storage and Use of Ammonia as a Fuel Applying the House of Quality

by Evanthia Kostidi, Xiaofei Cui and Dimitrios Lyridis

J. Mar. Sci. Eng. 2024, 12(7), 1097; https://doi.org/10.3390/jmse12071097 (registering DOI) - 28 Jun 2024

Viewed by 38

Abstract

Ammonia as a fuel has been known for several years, but only relatively recently has it attracted interest for study and use as a marine fuel. A forthcoming generation of sustainable, economically viable, and safe technologies for the large-scale onboard storage of ammonia [...] Read more.

Ammonia as a fuel has been known for several years, but only relatively recently has it attracted interest for study and use as a marine fuel. A forthcoming generation of sustainable, economically viable, and safe technologies for the large-scale onboard storage of ammonia as a marine fuel is being developed. This article presents a structured approach to carrying out Quality Function Deployment (QFD) for evaluating a project solution at the strategic level. The “House of Quality” (HoQ) method is utilised since it provides the means for inter-functional planning and communications among people with different problems and responsibilities. The project requirements are defined and lead to functional technical characteristics to satisfy these needs. The approach allows for the application of a weighting scheme to rank the perceived relative importance of the requirements, the difficulty involved in implementing the technologies, and the relationship between requirements and functional technical characteristics. QFD analysis prioritises safety compliance, technical specifications, emission control, and operational efficiency. The added value of this work is beyond the life of a project since it may provide assistance to the stakeholders in assessing the applicability of ammonia fuel solutions given the resources available to them. This feature will enable the justification of further investment into specific technologies based on their potential impact. Full article

(This article belongs to the Section Ocean Engineering)

35 pages, 2700 KiB

Open AccessArticle

Vibration Suppression of Two Adjacent Cables Using an Interconnected Tuned Mass Damper/Nonlinear Energy Sink

by Che Yao, Dejian Li and Xiaojun Wei

J. Mar. Sci. Eng. 2024, 12(7), 1096; https://doi.org/10.3390/jmse12071096 (registering DOI) - 28 Jun 2024

Viewed by 67

Abstract

Due to their high flexibility, low damping, and small mass, stay cables are prone to large-amplitude vibrations. Various mechanical measures, typically installed near the cable anchorage to the deck, have been developed to suppress cable vibration. These dampers, however, may not be effective [...] Read more.

Due to their high flexibility, low damping, and small mass, stay cables are prone to large-amplitude vibrations. Various mechanical measures, typically installed near the cable anchorage to the deck, have been developed to suppress cable vibration. These dampers, however, may not be effective for ultralong cables since the damper is close to the cable anchorage, the cable node. In this paper, a tuned mass damper (TMD)/nonlinear energy sink (NES) are considered for installation between two adjacent stay cables for vibration mitigation. Firstly, the static equilibrium equation of the stay cable–damper system is established, and the influence of the self-weight of the damper on cable shape is investigated. The governing equations describing the motion of the two adjacent cables with a damper are then established using the Hamilton principle, which are then solved by the method of separation of variables. For cases of swept-sine excitation and harmonic excitation, the optimal designs of TMD and NES are achieved with the purpose of suppressing the first- and third-mode-dominated vibrations, respectively. Both optimal TMD and NES may substantially suppress cable vibrations, with each having advantages under certain situations. Finally, the dynamic response characteristics of two adjacent cables with an optimal damper are analyzed. Interesting dynamic behaviors, such as energy input suppression, phase shift, cable frequency shift, and phase diagram boundary rotation, are identified, and their mechanisms are explained. Full article

(This article belongs to the Section Coastal Engineering)

17 pages, 1826 KiB

Open AccessArticle

Parameter Identification of Maritime Vessel Rudder PMSM Based on Extended Kalman Particle Filter Algorithm

by Tianqing Yuan, Tianli Wang, Jing Bai and Jingwen Fan

J. Mar. Sci. Eng. 2024, 12(7), 1095; https://doi.org/10.3390/jmse12071095 (registering DOI) - 28 Jun 2024

Viewed by 75

Abstract

To address the issue of system parameter variations during the operation of a maritime light vessel rudder permanent magnet synchronous motor (PMSM), an extended Kalman particle filter (EKPF) algorithm that combines a particle filter (PF) with an extended Kalman filter (EKF) is proposed [...] Read more.

To address the issue of system parameter variations during the operation of a maritime light vessel rudder permanent magnet synchronous motor (PMSM), an extended Kalman particle filter (EKPF) algorithm that combines a particle filter (PF) with an extended Kalman filter (EKF) is proposed in this paper. This approach enables the online identification of motor resistance and inductance. For highly nonlinear problems that are challenging for traditional methods such as Kalman filtering, this algorithm is typically a statistical and effective estimation method that usually yields good results. Firstly, a standard linear discrete parameter identification model is established for a PMSM. Secondly, the PF algorithm based on Bayesian state estimation as a foundation for subsequent research is derived. Thirdly, the advantages and limitations of the PF algorithm are analyzed, addressing issues such as sample degeneracy, by integrating it with the Kalman filtering algorithm. Specifically, the EKPF algorithm for online parameter identification is employed. Finally, the identification model within MATLAB/Simulink is constructed and the simulation studies are executed to ascertain the viability of our suggested algorithm. The outcomes from these simulations indicate that the proposed EKPF algorithm identifies resistance and inductance values both swiftly and precisely, markedly boosting the robustness and enhancing the control efficacy of the PMSM. Full article

(This article belongs to the Special Issue Advancements in Power Management Systems for Hybrid Electric Vessels)

27 pages, 12927 KiB

Open AccessArticle

Coastal Erosion Dynamics and Protective Measures in the Vietnamese Mekong Delta

by Tran Van Ty, Dinh Van Duy, Lam Tan Phat, Huynh Vuong Thu Minh, Nguyen Truong Thanh, Nguyen Thi Ngoc Uyen and Nigel K. Downes

J. Mar. Sci. Eng. 2024, 12(7), 1094; https://doi.org/10.3390/jmse12071094 - 28 Jun 2024

Viewed by 110

Abstract

The dynamic shifts in shorelines due to erosion and deposition have become a significant challenge in coastal zone management, particularly in the context of climate change and rising sea levels. This paper evaluates the shoreline protection and efficiency of various wave-reducing breakwaters in [...] Read more.

The dynamic shifts in shorelines due to erosion and deposition have become a significant challenge in coastal zone management, particularly in the context of climate change and rising sea levels. This paper evaluates the shoreline protection and efficiency of various wave-reducing breakwaters in the Vietnamese Mekong Delta. The delta exemplifies the coastal erosion issue faced by deltas worldwide. Landsat satellite images were used to establish a coastal development map for the period 2000 to 2022. The wave data in front and behind the breakwaters were analyzed to assess the wave reduction efficiency of various breakwater structures. Our results reveal that coastal erosion is deeply concerning, with almost 40% of the coastline experiencing severe erosion. Hotspot areas have been observed to reach annual erosion rates of nearly 95 m per year. The majority of provinces have adopted protective measures, with 68% of affected shorelines protected to some degree. Our results show breakwaters to be highly effective in reducing wave height, with a 62% reduction in waves reaching the shore. The process of creating offset has taken place in the area from the breakwater back to the mainland, with the rate of increase in compensation also quite fast at up to 3.1 cm/month. The stability of the pile–rock is very high; however, it is necessary to add rock to compensate for the settlement of the rock part. Full article

(This article belongs to the Special Issue Recent Advances in Estuarine Monitoring and Management)

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22 pages, 6617 KiB

Open AccessArticle

Assessment of a Hybrid Wind–Wave Energy Converter System in Nearshore Deployment

by Phan Cong Binh, Tri Dung Dang and Kyoung Kwan Ahn

J. Mar. Sci. Eng. 2024, 12(7), 1093; https://doi.org/10.3390/jmse12071093 - 28 Jun 2024

Viewed by 126

Abstract

A modeling technique for a nearshore hybrid wind–wave energy converter system (HWWECS) is presented in this research. The model consists of the buoy, wind system, and generator, allowing simulation of the HWWECS’s behavior in response to varied wave circumstances, such as different wave [...] Read more.

A modeling technique for a nearshore hybrid wind–wave energy converter system (HWWECS) is presented in this research. The model consists of the buoy, wind system, and generator, allowing simulation of the HWWECS’s behavior in response to varied wave circumstances, such as different wave heights and periods. The HWWECS is made up of two buoy units and a wind system that work together to power a generator. The Wave Analysis at Massachusetts Institute of Technology (WAMIT) software is used to calculate the hydrodynamic forces. A variable inertia hydraulic flywheel is used to bring the system into resonance with incident wave frequencies in order to improve power production. Full article

(This article belongs to the Special Issue The Control, Modeling, and the Development of Wave Energy Convertors)

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16 pages, 4411 KiB

Open AccessArticle

Real-Time Infrared Sea–Sky Line Region Detection in Complex Environment Based on Deep Learning

by Yongfei Wang, Fan Li, Jianhui Zhao and Jian Fu

J. Mar. Sci. Eng. 2024, 12(7), 1092; https://doi.org/10.3390/jmse12071092 - 28 Jun 2024

Viewed by 146

Abstract

Fast and accurate infrared (IR) sea–sky line region (SSLR) detection can improve the early warning capability of the small targets that appear in the remote sea–sky junction. However, the traditional algorithms struggle to achieve high precision, while the learning-based ones have low detection [...] Read more.

Fast and accurate infrared (IR) sea–sky line region (SSLR) detection can improve the early warning capability of the small targets that appear in the remote sea–sky junction. However, the traditional algorithms struggle to achieve high precision, while the learning-based ones have low detection speed. To overcome these problems, a novel learning-based algorithm is proposed; rather than detecting the sea–sky line first, the proposed algorithm directly provides SSLR, which mainly consists of three parts: Firstly, an IR sea–sky line region detection module (ISRDM) is proposed, which combines strip pooling and the connection mode of a cross-stage partial network to extract the features of the SSLR target, with an unbalanced aspect ratio, more specifically, thus improving the detection accuracy. Secondly, a lightweight backbone is presented to reduce the parameters of the model and, therefore, improve the inference speed. Finally, a Detection Head Based on the spatial-aware attention module (SAMHead) is designed to enhance the perception ability of the SSLR and further reduce the inference time. Extensive experiments conducted on three datasets with more than 26,000 frames show that the proposed algorithm achieved approximately 80% average precision (AP), outperforms the state-of-the-art algorithms in accuracy, and can realize real-time detection. Full article

(This article belongs to the Special Issue Machine Learning Methodologies and Ocean Science)

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15 pages, 5302 KiB

Open AccessArticle

Deep Learning-Based Geomorphic Feature Identification in Dredge Pit Marine Environment

by Wenqiang Zhang, Xiaobing Chen, Xiangwei Zhou, Jianhua Chen, Jianguo Yuan, Taibiao Zhao and Kehui Xu

J. Mar. Sci. Eng. 2024, 12(7), 1091; https://doi.org/10.3390/jmse12071091 - 28 Jun 2024

Viewed by 151

Abstract

Deep learning methods paired with sidescan sonar (SSS) are commonly used in underwater search-and-rescue operations for drowning victims, wrecks, and airplanes. However, these techniques are primarily used to detect mine-like objects and are rarely applied to identifying features in dynamic dredge pit environments. [...] Read more.

Deep learning methods paired with sidescan sonar (SSS) are commonly used in underwater search-and-rescue operations for drowning victims, wrecks, and airplanes. However, these techniques are primarily used to detect mine-like objects and are rarely applied to identifying features in dynamic dredge pit environments. In this study, we present a Sandy Point dredge pit (SPDP) dataset, in which high-resolution SSS data were collected from the west flank of the Mississippi bird-foot delta on the Louisiana inner shelf. This dataset contains a total of 385 SSS images. We then introduce a new Effective Geomorphology Classification model (EGC). Through ablation studies, we analyze the utility of transfer learning on different model architectures and the impact of data augmentations on model performance. This EGC model makes geomorphic feature identification in dredge pit environments, which requires extensive experience and professional knowledge, a quick and efficient task. The combination of SSS images and the EGC model is a cost-effective and valuable toolkit for hazard monitoring in marine dredge pit environments. The SPDP SSS image dataset, especially the feature of pit walls without a rotational slump, is also valuable for other machine learning models. Full article

(This article belongs to the Section Coastal Engineering)

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19 pages, 1611 KiB

Open AccessArticle

Detection and Analysis of Corrosion on Coated Metal Surfaces using Enhanced YOLO v5 Algorithm for Anti-Corrosion Performance Evaluation

by Qifeng Yu, Yudong Han, Wuguang Lin and Xinjia Gao

J. Mar. Sci. Eng. 2024, 12(7), 1090; https://doi.org/10.3390/jmse12071090 - 27 Jun 2024

Viewed by 186

Abstract

This study addresses the severe corrosion issues in the coastal regions of southern China by proposing an improved YOLO v5-GOLD-NWD model. Utilizing corrosion data from the National Center for Materials Corrosion and Protection Science of China, a dataset was constructed for metal-surface corrosion [...] Read more.

This study addresses the severe corrosion issues in the coastal regions of southern China by proposing an improved YOLO v5-GOLD-NWD model. Utilizing corrosion data from the National Center for Materials Corrosion and Protection Science of China, a dataset was constructed for metal-surface corrosion under different protective coatings. This dataset was used for model training, testing, and comparison. Model accuracy was validated using precision, recall, F1 score, and prediction probability. The results demonstrate that the proposed improved model exhibits better identification precision in metal corrosion detection, achieving 78%, a 4% improvement compared to traditional YOLO v5 models. Additionally, through identification and statistical analysis of corrosion image datasets from five types of coated metal specimens, it was found that powder epoxy coating, fluorocarbon coating, epoxy coating, and chlorinated rubber coating showed good corrosion resistance after 24 months of exposure. Conversely, Wuxi anti-fouling coating exhibited poor corrosion resistance. After 60 months of natural exposure, the powder epoxy coating specimens had the highest corrosion occurrence probability, followed by chlorinated rubber coating and epoxy coating, with fluorocarbon coating showing relatively lower probability. The fluorocarbon coating demonstrated relatively good corrosion resistance at both 24 and 60 months of exposure. The findings of this study provide a theoretical basis for enhancing the corrosion protection effectiveness of steel structures in coastal areas. Full article

(This article belongs to the Special Issue Advanced Research on the Sustainable Maritime Transportation (2nd Edition))

26 pages, 3198 KiB

Open AccessArticle

Empirical Orthogonal Function Analysis on Long-Term Profile Evolution of Tidal Flats along a Curved Coast in the Qiantang River Estuary, China

by Ying Li and Dongzi Pan

J. Mar. Sci. Eng. 2024, 12(7), 1089; https://doi.org/10.3390/jmse12071089 - 27 Jun 2024

Viewed by 186

Abstract

Tidal flats are dynamic coastal ecosystems continually reshaped by natural processes and human activities. This study investigates the application of Empirical Orthogonal Function (EOF) analysis to the long-term profile evolution of tidal flats along the Jiansan Bend of the Qiantang River Estuary, China. [...] Read more.

Tidal flats are dynamic coastal ecosystems continually reshaped by natural processes and human activities. This study investigates the application of Empirical Orthogonal Function (EOF) analysis to the long-term profile evolution of tidal flats along the Jiansan Bend of the Qiantang River Estuary, China. By applying EOF analysis to profiles observed from 1984 to 2023, this study identifies dominant modes of variability and their spatial and temporal characteristics, offering insights into the complex sediment transport and morphological evolution processes. EOF analysis helps unravel the complex interactions between natural and anthropogenic factors shaping tidal flats, with the first three eigenfunctions accounting for over 90% of the observed variance. The first spatial eigenfunction captures the primary trend, while the subsequent two eigenfunctions reveal secondary and tertiary modes of variability. A conceptual model developed in this study elucidates the interplay between hydrodynamic forces and morphological changes, highlighting the rotation and oscillation of tidal flat profiles in response to seasonal variations in hydrological conditions. The findings emphasize the effectiveness of EOF analysis in capturing significant geomorphological processes and underscore its potential in enhancing the understanding of tidal flat dynamics, thereby informing more effective management and conservation strategies for these critical coastal environments. Full article

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

16 pages, 887 KiB

Open AccessArticle

Risk Analysis of Pirate Attacks on Southeast Asian Ships Based on Bayesian Networks

by Qiong Chen, Jinsheng Zhang, Jiaqi Gao, Yui-Yip Lau, Jieming Liu, Mark Ching-Pong Poo and Pengfei Zhang

J. Mar. Sci. Eng. 2024, 12(7), 1088; https://doi.org/10.3390/jmse12071088 (registering DOI) - 27 Jun 2024

Viewed by 231

Abstract

As a bridge for international trade, maritime transportation security is crucial to the global economy. Southeast Asian waters have become a high-incidence area of global piracy attacks due to geographic location and complex security situations, posing a great threat to the development of [...] Read more.

As a bridge for international trade, maritime transportation security is crucial to the global economy. Southeast Asian waters have become a high-incidence area of global piracy attacks due to geographic location and complex security situations, posing a great threat to the development of the Maritime Silk Road. In this study, the factors affecting the risk of pirate attacks are analyzed in depth by using the Global Ship Piracy Attacks Report from the IMO Global Integrated Shipping Information System (GISIS) database (i.e., 2013–2022) in conjunction with a Bayesian Network (BN) model, and the Expectation Maximization algorithm is used to train the model parameters. The results show that piracy behaviors and the ship’s risk are the key factors affecting the risk of pirate attacks, and suggestions are made to reduce the risk of pirate attacks. This study develops a theoretical basis for preventing and controlling the risk of pirate attacks on ships, which helps maintain the safety of ship operations. Full article

(This article belongs to the Section Ocean Engineering)

17 pages, 822 KiB

Open AccessArticle

Multidisciplinary Design Optimization of Underwater Vehicles Based on a Combined Proxy Model

by Shaojun Sun and Weilin Luo

J. Mar. Sci. Eng. 2024, 12(7), 1087; https://doi.org/10.3390/jmse12071087 - 27 Jun 2024

Viewed by 149

Abstract

To improve the efficiency of the multidisciplinary design optimization of underwater vehicles, this paper proposes a combined proxy model with adaptive dynamic sampling. The radial basis function model (RBF), Kriging model, and polynomial response surface model (PRS) are used to construct the proxy [...] Read more.

To improve the efficiency of the multidisciplinary design optimization of underwater vehicles, this paper proposes a combined proxy model with adaptive dynamic sampling. The radial basis function model (RBF), Kriging model, and polynomial response surface model (PRS) are used to construct the proxy model. Efficient sample points are collected based on the synthetic minority oversampling technique (SMOTE) algorithm and the lower confidence bound (LCB) criterion. The proxy model process is integrated after dynamic sampling. The collaborative optimization framework is used, which considers the coupling between the main system set and the subsystem set. The hierarchical analysis method is used to transform the multidisciplinary optimization problem into a single-objective optimization problem. Computational fluid dynamics (CFD) numerical simulation is utilized to simulate underwater submarine navigation. The optimization strategy is applied to the underwater vehicle SUBOFF to optimize resistance and energy consumption. Three dynamic proxy models and three static proxy models are compared. The results show that the optimization efficiency of the underwater vehicle has been improved. To prove the generalization performance of the proposed combined proxy model, a reducer example is investigated for comparison. The results show that the combined proxy model (CPM) is highly accurate and has excellent generalization performance. Full article

(This article belongs to the Section Ocean Engineering)

28 pages, 15506 KiB

Open AccessArticle

Evaluation of Influencing Factors in Cleaning Performance for Bio-Fouling Removal Based on High-Pressure Water Jets

by Jaehyeon Ahn, Kaicheng Yan, Salim Abdullah Bazher, Jungkeun Oh, Daewon Seo, Su-gil Cho and Hyungwoo Kim

J. Mar. Sci. Eng. 2024, 12(7), 1086; https://doi.org/10.3390/jmse12071086 - 27 Jun 2024

Viewed by 185

Abstract

Regular inspections and hull cleanings are essential to prevent bio-fouling on ships. However, traditional cleaning methods such as brush cleaning and high-pressure water-jet cleaning at docks are ineffective in cleaning niche areas like bow thrusters and sea chests. Consequently, cleaning robots based on [...] Read more.

Regular inspections and hull cleanings are essential to prevent bio-fouling on ships. However, traditional cleaning methods such as brush cleaning and high-pressure water-jet cleaning at docks are ineffective in cleaning niche areas like bow thrusters and sea chests. Consequently, cleaning robots based on brushes and water jets have been developed to effectively remove bio-fouling. However, there are concerns that brushes may damage hull coatings, allowing bio-fouling to penetrate the damaged areas. In this study, removal experiments were conducted to identify the most dominant factor in fouling removal using water jet-based cleaning, in preparation for the development of non-contact cavitation high-pressure water jet-cleaning robots. The Taguchi method was used to identify influential factors and generate experimental conditions, and equipment systems for the removal experiments were established. Image analysis was performed to assess the bio-fouling occurrences on each specimen before and after cleaning, and numerical simulations of the nozzle were conducted to estimate stagnation pressure and wall shear stress to confirm the effect on micro-fouling removal. The results indicated that pump pressure is the most influential factor in removing large bio-fouling organisms grown in marine environments and on ship surfaces. Full article

(This article belongs to the Section Ocean Engineering)

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16 pages, 10976 KiB

Open AccessArticle

Remote-Sensing Estimation of Upwelling-Frequent Areas in the Adjacent Waters of Zhoushan (China)

by Teng Xiao, Jiajun Feng, Zhongfeng Qiu, Rong Tang, Aibo Zhao, Kapo Wong, Jin Yeu Tsou and Yuanzhi Zhang

J. Mar. Sci. Eng. 2024, 12(7), 1085; https://doi.org/10.3390/jmse12071085 - 27 Jun 2024

Viewed by 158

Abstract

Upwelling, which mixes deep and surface waters, significantly enhances the productivity of surface waters and plays a critical role in marine ecosystems, especially in key fishing areas like Zhoushan. This study utilized merged sea surface temperature data and an upwelling edge detection algorithm [...] Read more.

Upwelling, which mixes deep and surface waters, significantly enhances the productivity of surface waters and plays a critical role in marine ecosystems, especially in key fishing areas like Zhoushan. This study utilized merged sea surface temperature data and an upwelling edge detection algorithm based on temperature gradients to analyze the characteristics of upwelling in Zhoushan and the Yangtze River Estuary over the past 28 years. The results indicate that upwelling in Zhoushan begins in April, peaks in July, gradually weakens, and disappears by October. The phenomenon is most pronounced during the summer months (June to August), with significant spatial distribution differences in April and September. Notably, high probability values of upwelling centers and core areas are mainly concentrated near Ma’an Island, Zhongjieshan Island, and Taohua Island. In these areas, upwelling remains stable during the summer, forming a unique “footprint” distribution pattern, and these are also the locations of the Zhoushan National Marine Ranch. From April to August, the extent of the upwelling area gradually decreases and stabilizes. These findings emphasize the frequent upwelling activity around Zhoushan and its significant contribution to the formation of local fisheries. Additionally, considering that the formation of natural upwelling in the East China Sea depends on the southern monsoon, the study suggests establishing artificial upwelling systems during periods unfavorable for natural upwelling, based on high probability areas, to enhance fishery yields and support the development of local fisheries. Full article

(This article belongs to the Special Issue New Advances in Marine Remote Sensing Applications)

19 pages, 15698 KiB

Open AccessArticle

Enhancing Maritime Navigation with Mixed Reality: Assessing Remote Pilotage Concepts and Technologies by In Situ Testing

by Arbresh Ujkani, Pascal Hohnrath, Robert Grundmann and Hans-Christoph Burmeister

J. Mar. Sci. Eng. 2024, 12(7), 1084; https://doi.org/10.3390/jmse12071084 - 27 Jun 2024

Viewed by 244

Abstract

In response to the evolving landscape of maritime operations, new technologies are on the horizon as mixed reality (MR), which shall enhance navigation safety and efficiency during remote assistance as, e.g., in the remote pilotage use case. However, up to now, it is [...] Read more.

In response to the evolving landscape of maritime operations, new technologies are on the horizon as mixed reality (MR), which shall enhance navigation safety and efficiency during remote assistance as, e.g., in the remote pilotage use case. However, up to now, it is uncertain if this technology can provide benefits in terms of usability and situational awareness (SA) compared with screen-based visualizations, which are established in maritime navigation. Thus, this paper initially tests and assesses novel approaches to pilotage in the congested maritime environment, which integrates augmented reality (AR) for ship captains and virtual reality (VR) and desktop applications for pilots. The tested prototype employs AR glasses, notably the Hololens 2, to superimpose the Automatic Identification System (AIS) data directly into the captain’s field of view, while pilots on land receive identical information alongside live 360-degree video feeds from cameras installed on the ship. Additional minimum functionalities include waypoint setting, bearing indicators, and voice communication. The efficiency and usability of these technologies are evaluated through in situ tests conducted with experienced pilots on a real ship using the System Usability Scale, the Situational Awareness Rating Technique, as well as Simulator Sickness Questionnaires during the assessment. This includes a first indicative comparison of VR and desktop applications for the given use case. Full article

(This article belongs to the Special Issue Intelligent Ships and Waterways: Design, Operation and Advanced Technology)

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22 pages, 6051 KiB

Open AccessArticle

Medium-Term Effects of Dune Erosion and Longshore Sediment Transport on Beach–Dune Systems Evolution

by Ana Margarida Ferreira, Carlos Coelho and Paulo A. Silva

J. Mar. Sci. Eng. 2024, 12(7), 1083; https://doi.org/10.3390/jmse12071083 - 27 Jun 2024

Viewed by 171

Abstract

Beach–dune systems are highly dynamic features of the coastal system, the evolution of which is influenced by several processes that occur at very different spatial and temporal scales. To mitigate shoreline retreat that threatens extensive coastal areas worldwide, coastal erosion mitigation measures are [...] Read more.

Beach–dune systems are highly dynamic features of the coastal system, the evolution of which is influenced by several processes that occur at very different spatial and temporal scales. To mitigate shoreline retreat that threatens extensive coastal areas worldwide, coastal erosion mitigation measures are implemented, aiming to make coastal areas resilient to the effects induced by coastal erosion and the anticipated climate change related to storms, flood events and sea level rise. Numerical modelling can support planned and sustainable coastal management from a medium-to-long-term perspective (decades). This research focuses on presenting contributions regarding the numerical modelling of subaerial beach dynamics (berm width and dune systems interactions) from a medium-term perspective. The method applied is based on a combination of the results of two simplified numerical models (the LTC and CS-Model). The results demonstrate the potential of the proposed combined model for medium-term projections, allowing for the interpretation of beach–dune dynamics and the evaluation of the importance of longshore and cross-shore sediment transport processes. Full article

(This article belongs to the Special Issue Assessment of Multi-scale Coastal Evolution in a Changing Climate: from Observation to Modelling)

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18 pages, 1965 KiB

Open AccessArticle

Task-Driven Learning Downsampling Network Based Phase-Resolved Wave Fields Reconstruction with Remote Optical Observations

by Tianyu Mou, Zhipeng Shen and Guangshi Xue

J. Mar. Sci. Eng. 2024, 12(7), 1082; https://doi.org/10.3390/jmse12071082 - 27 Jun 2024

Viewed by 184

Abstract

We develop a phase-resolved wave field reconstruction method by the learning-based downsampling network for processing large amounts of inhomogeneous data from non-contact wave optical observations. The Waves Acquisition Stereo System (WASS) extracts dense point clouds from ocean wave snapshots. We couple learning-based downsampling [...] Read more.

We develop a phase-resolved wave field reconstruction method by the learning-based downsampling network for processing large amounts of inhomogeneous data from non-contact wave optical observations. The Waves Acquisition Stereo System (WASS) extracts dense point clouds from ocean wave snapshots. We couple learning-based downsampling networks with the phase-resolved wave reconstruction algorithm, and the training task is to improve the wave reconstruction completeness ratio

C_{R}

. The algorithm first achieves initial convergence and task-optimized performance on numerical ocean waves built by the linear wave theory model. Results show that the trained sampling network can lead to a more uniform spatial distribution of sampling points and improve

C_{R}

at the observed edge regions far from the optical camera. Finally, we apply our algorithm to a natural ocean wave dataset. The average completeness ratio is improved over 30% at low sampling ratios (

S_{R} \in [2^{- 9}, 2^{- 7}]

) compared to the traditional FPS method and Random sampling method. Moreover, the relative residual between the final reconstructed wave and the natural wave is less than 15%, which provides an efficient tool for wave reconstruction in ocean engineering. Full article

(This article belongs to the Section Ocean Engineering)

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36 pages, 9213 KiB

Open AccessArticle

Scenario Analysis of Shorelines, Coastal Erosion, and Land Use/Land Cover Changes and Their Implication for Climate Migration in East and West Africa

by Oye Ideki and Osinachi Ajoku

J. Mar. Sci. Eng. 2024, 12(7), 1081; https://doi.org/10.3390/jmse12071081 - 26 Jun 2024

Viewed by 179

Abstract

Climate change-induced sea level rise, shoreline changes, and coastal erosion are projected to drive massive population displacement and mobility in Africa. This study was conducted to examine the pattern of shoreline changes, coastal erosion, land use/land cover dynamics, projections, and their implications on [...] Read more.

Climate change-induced sea level rise, shoreline changes, and coastal erosion are projected to drive massive population displacement and mobility in Africa. This study was conducted to examine the pattern of shoreline changes, coastal erosion, land use/land cover dynamics, projections, and their implications on internal migration in Senegal, Kenya, and Tanzania, representing West and East Africa. The digitized shoreline was mapped into erosion, accretion, and trend analysis, which further explains the vulnerability and physical processes that could trigger human displacement within the context of environmental/climate migration. Analysis of land use and land cover dynamics was obtained from Landsat 5 TM of 1986, Landsat 7 ET of 2006, Landsat 8 OLI/TIRS of 2016, and Landsat 9 OLI/TIRS of 2022 and computed using ArcGIS 10.7 for land-use change and percentage change in square kilometers was conducted to examine land use/land cover dynamics and their contributions to the risk of coastal erosion in the study regions. The outcome of the shoreline analysis reveals that 972.03 sqkm of land has been lost to coastal erosion in Senegal from 1986 to 2022 with 2016–2022 described as the period with the highest in terms of land loss. In Kenya, −463.30 sqkm of land has also been lost to coastal erosion and agents of wave processes, with 1986–2006 recording the highest share of −87.74% loss of valuable land, while in Tanzania, −1033.35 sqkm of valuable land has been lost from 1986 to 2022 to coastal erosion, with 2006–2016 alone recording −10.4634% of land loss. The result of the land use/land cover percentage change analysis indicates a massive loss of vegetation cover with a significant increase in settlement representing urbanization. The scenario analysis of the shoreline at 10, 20, and 30 m indicates that 567 persons per sqkm at 10 m, 25,904.6 persons per sqkm at 20 m, and 25,904.5 persons per sqkm will be displaced in Senegal at 30 m. In Kenya, 57,746 persons per sqkm are projected to be displaced at 10 m while 1210.5 persons per sqkm will be displaced at 20 m and 7737.32 persons per sqkm will be displaced at 30 m. In Tanzania, the maximum population density projected to be displaced at 10, 20, and 30 m is 10,260.97 per sqkm. Structured questionnaires were administered to elicit responses from coastal dwellers on their perception of coastal erosion and climate migration as part of ground truthing and the result of the survey affirms that coastal erosion and its exposure are the major drivers of climate migration in the study area. Full article

(This article belongs to the Section Coastal Engineering)

23 pages, 6760 KiB

Open AccessArticle

Hybrid Torque Coefficient Control of Average-to-Peak Ratio for Turbine Angular Velocity Reduction in Oscillating-Water-Column-Type Wave Energy Converter

by Hyeongyo Chae and Chan Roh

J. Mar. Sci. Eng. 2024, 12(7), 1080; https://doi.org/10.3390/jmse12071080 - 26 Jun 2024

Viewed by 229

Abstract

Wave energy converters (WECs) have significant potential to meet the increasing energy demands and using an oscillating water column (OWC) is one of the most reliable ways to implement them. The OWC has a simple structure and excellent durability. However, control of the [...] Read more.

Wave energy converters (WECs) have significant potential to meet the increasing energy demands and using an oscillating water column (OWC) is one of the most reliable ways to implement them. The OWC has a simple structure and excellent durability. However, control of the power take-off (PTO) system is difficult due to variability in the input wave energy. In particular, the design and control of the PTO system are complex, as the average-to-peak ratio of the output generation is large. Owing to the nature of the OWC, if the energy above the rating cannot be controlled, the power generated is inevitably reduced due to the decrease in operating time. We propose a method to reduce the angular speed of the turbine by dividing the section according to the input energy and correspondingly changing the torque coefficient, thereby increasing the operating time of the OWC. The control methods for the PTO system of OWC are verified through a 30 kW full-scale experimental device to be installed in a real sea area. The full-scale experimental device consists of an inverter that simulates the mechanical torque of an OWC based on the aerodynamic simulation of an impulse turbine, an induction motor, a permanent magnet synchronous generator, an AC/DC converter, and a battery for the energy storage system. The performance of conventional control methods and the proposed method are compared based on the results of numerical simulations and experiments. We show that the fluctuation in the turbine angular velocity in the proposed method is significantly reduced compared with that in the conventional control methods under regular and irregular wave conditions. Full article

(This article belongs to the Special Issue The Control, Modeling, and the Development of Wave Energy Convertors)

17 pages, 8542 KiB

Open AccessArticle

Effect of Hydrate Saturation on Permeability Anisotropy for Hydrate-Bearing Turbidite Sediments Based on Pore-Scale Seepage Simulation

by Ruirui Li, Zhenhua Han, Luqing Zhang, Jian Zhou and Song Wang

J. Mar. Sci. Eng. 2024, 12(7), 1079; https://doi.org/10.3390/jmse12071079 - 26 Jun 2024

Viewed by 242

Abstract

The permeability of natural gas hydrate (NGH) turbidite reservoirs typically exhibits significant anisotropy, with anisotropy being a crucial basis for evaluating reservoir production. The presence of hydrates, as a crucial constituent of the solid framework, not only impacts the overall permeability but also [...] Read more.

The permeability of natural gas hydrate (NGH) turbidite reservoirs typically exhibits significant anisotropy, with anisotropy being a crucial basis for evaluating reservoir production. The presence of hydrates, as a crucial constituent of the solid framework, not only impacts the overall permeability but also influences the permeability anisotropy. To investigate the saturation sensitivity of permeability anisotropy, a series of simulations are performed by integrating particle flow and computational fluid dynamics methods to construct the homogeneous and layered numerical samples and compute the evolution of permeability anisotropy. It is shown that the permeability is isotropic for homogeneous sediments and the isotropy remains unchanged regardless of variations in hydrate saturation. The permeability of layered sediments, in contrast, exhibits significant anisotropy due to the presence of dominant channels within the coarse layer. For uniformly distributed hydrates, the more effective blockage in coarse layers results in a reduction in anisotropy. While for preferentially distributed hydrates, the excess blocking of coarse layers makes the dominant channels transfer to the fine layers, the further blocking causes a U-shaped anisotropy–saturation curve characterized by a decrease–increase transformation. During the reservoir production process, the preponderance channels blocked by hydrates will be cleared and the horizontal permeability will significantly increase. As a result, the production efficiency of horizontal wells may exceed expectations. The findings offer a parameter support for production estimation and environmental assessment. Full article

(This article belongs to the Section Marine Energy)

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39 pages, 19806 KiB

Open AccessArticle

Feasibility of the Northern Sea Route: Impact of Sea Ice Thickness Uncertainty on Navigation

by Tongtong Li, Yangjun Wang, Yan Li, Bin Wang, Quanhong Liu and Xi Chen

J. Mar. Sci. Eng. 2024, 12(7), 1078; https://doi.org/10.3390/jmse12071078 - 26 Jun 2024

Viewed by 212

Abstract

With the accelerated melting of the Arctic sea ice, the opening of the Northern Sea Route (NSR) of the Arctic is becoming increasingly accessible. The purpose of this paper was to examine the impact of uncertainty in sea ice thickness (SIT) data on [...] Read more.

With the accelerated melting of the Arctic sea ice, the opening of the Northern Sea Route (NSR) of the Arctic is becoming increasingly accessible. The purpose of this paper was to examine the impact of uncertainty in sea ice thickness (SIT) data on the opening of the NSR and to quantify the extent of this impact, which is essential to the regularized operation of polar shipping. A quantitative assessment framework was proposed to examine the influence of SIT data uncertainty on navigational uncertainty through three aspects: the navigational spatiotemporal windows, the distribution of safe sailing speeds, and the uncertainty in optimal route planning by employing four distinct SIT datasets. Furthermore, the sensitivity of navigational spatiotemporal windows, the distribution of safe sailing speeds, and route planning to variations in SIT were also evaluated. Results show that experiment results based on CS2SMOS exhibit a more aggressive profile, while results based on CPOM are more conservative. The difference in SIT data has a significant impact on the proportion of operations subject to special consideration areas, such as safety speed, sailing time, and distance in NEP. A 0.1 m discrepancy in sea ice thickness data results in an approximate 0.067 change in the proportion of operations within special consideration areas. This discrepancy also leads to an approximate speed change of 0.89 knots, a navigation duration change of approximately 4 days, and a distance change of 152 km within specified limits. Full article

(This article belongs to the Section Ocean Engineering)

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33 pages, 1445 KiB

Open AccessSystematic Review

A Systematic Review of Oceanic-Atmospheric Variations and Coastal Erosion in Continental Latin America: Historical Trends, Future Projections, and Management Challenges

by Ruby Vallarino-Castillo, Vicente Negro-Valdecantos and José María del Campo

J. Mar. Sci. Eng. 2024, 12(7), 1077; https://doi.org/10.3390/jmse12071077 - 26 Jun 2024

Viewed by 234

Abstract

The intricate interplay of oceanic-atmospheric variations has intensified erosive processes on sandy beaches in recent decades, with climate change expected to exacerbate these impacts in the future. Projections for the southern Atlantic and Pacific regions of continental Latin America predict increased extreme events [...] Read more.

The intricate interplay of oceanic-atmospheric variations has intensified erosive processes on sandy beaches in recent decades, with climate change expected to exacerbate these impacts in the future. Projections for the southern Atlantic and Pacific regions of continental Latin America predict increased extreme events and heightened impacts on sandy beaches, highlighting disparities in studies addressing coastal erosion and its causes. To address these risks, a systematic review is proposed to analyze historical trends and projections, aiming to inform local-level studies and management strategies for at-risk coastal communities. Reviewing 130 research papers, insights reveal the influence of climatic events like El Niño and La Niña on coastal dynamics, as well as the effects of storm intensification and extreme events such as high-intensity waves and storm surges on Latin American coasts, resulting in ecosystem, economic, and infrastructure losses. Projections indicate a rise in the population inhabiting Low Elevation Coastal Zones (LECZ) by the century’s end, emphasizing the urgent need for effective management and planning. Community engagement in erosion monitoring and adaptation programs is crucial for addressing these challenges and developing robust, sustainable, long-term adaptation strategies. This study aims to enhance the understanding of coastal erosion in Latin American communities addressing future coastal risks. Full article

(This article belongs to the Section Coastal Engineering)

27 pages, 2840 KiB

Open AccessArticle

Numerical Simulations of a Ship’s Maneuverability in Shallow Water

by Jing Li, Qing Wang, Kai Dong and Xianzhou Wang

J. Mar. Sci. Eng. 2024, 12(7), 1076; https://doi.org/10.3390/jmse12071076 - 26 Jun 2024

Viewed by 202

Abstract

It is necessary to maintain maneuverability for ship navigation in shallow water, such as channels, ports and other confined waters. In this study, a turning circle maneuver with 35° rudder deflection and a 20/5 zigzag maneuver for KVLCC2 in shallow waters are tested [...] Read more.

It is necessary to maintain maneuverability for ship navigation in shallow water, such as channels, ports and other confined waters. In this study, a turning circle maneuver with 35° rudder deflection and a 20/5 zigzag maneuver for KVLCC2 in shallow waters are tested numerically to directly predict the maneuverability of the ship in shallow water. A viscous in-house CFD solver is applied with the dynamic overset grid approach. The impacts of the water depth on the ship’s maneuverability in terms of turning and zigzag competence are evaluated, and the underlying mechanism is analyzed. The numerical method is validated by comparing it with experimental data on the turning indices, which shows good agreement. It is demonstrated that the turning capability become worse with a smaller depth–draft ratio, thus resulting in a lower yaw rate and a greater steady turning diameter. However, the drift angle and lateral speed are reduced with a smaller depth–draft ratio for zigzag maneuvers, but the overshoot angle and turn lag vary with the water depth non-monotonically. Full article

(This article belongs to the Special Issue Models and Simulations of Ship Manoeuvring)

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J. Mar. Sci. Eng., Volume 12, Issue 7 (July 2024) – 70 articles

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