International Journal of Naval Architecture and Ocean Engineering最新文献

{"title":"Numerical investigation of control strategies on a coupled ship propulsion system in waves","authors":"Chuma Ncobo,&nbsp;Jonas Thiaucourt,&nbsp;Xavier Tauzia,&nbsp;Lionel Gentaz","doi":"10.1016/j.ijnaoe.2026.100745","DOIUrl":"10.1016/j.ijnaoe.2026.100745","url":null,"abstract":"<div><div>This paper investigates two engine control strategies — constant rack (CR) and speed controller (SC) — for a coupled ship propulsion system in regular head waves. The study decomposes the efficiency chain into components to identify physical mechanisms behind performance differences. By integrating a mean value engine model with a time-domain ship simulator, we analyze transient interactions between hull, propeller, and engine under realistic seaway conditions. Results demonstrate that CR achieves superior fuel efficiency (up to 2.49% improvement), particularly in long-wavelength seas. This advantage stems from reduced turbo-lag effects and more stable air–fuel dynamics that minimize transient thermodynamic losses. However, CR induces significant engine speed fluctuations that may limit practical application. In contrast, SC provides better speed regulation but increases fuel consumption due to turbo-lag and unsteady air–fuel dynamics. Hydrodynamic effects contribute through control-strategy-induced variations in ship speed and wave resistance, though to a lesser extent. These findings highlight the importance of modeling both engine dynamics and nonlinear hydrodynamic effects when evaluating propulsion control strategies.</div></div>","PeriodicalId":14160,"journal":{"name":"International Journal of Naval Architecture and Ocean Engineering","volume":"18 ","pages":"Article 100745"},"PeriodicalIF":3.9,"publicationDate":"2026-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147396766","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"CFD-based hydrodynamics modeling of control fins with low aspect ratio for AUVs","authors":"Younhee Kwon ,&nbsp;Dong-Hwan Kim ,&nbsp;Minchang Kim ,&nbsp;Jeonghwa Seo","doi":"10.1016/j.ijnaoe.2026.100764","DOIUrl":"10.1016/j.ijnaoe.2026.100764","url":null,"abstract":"<div><div>Autonomous underwater vehicles (AUVs) are equipped with short span control fins owing to geometric constraints, resulting in difficulties in design and control of AUVs. The present study proposes a generalized approach for hydrodynamics modeling of AUV control fins based on validated computational fluid dynamics analyses. The lift generation, inflow velocity, and interaction with the vehicle body are systematically investigated and modeled with respect to fin span variation. The lift generation is modeled as the function of the fin aspect ratio and angle of attack, while conventional modeling considers only the fin aspect ratio. Inflow model is developed based on the lift generation model, to be consistent with nominal flow field measurements. The numerical test results confirm that the longer span fins reduce the fin-body interaction, which is found to degrade the vehicle's turning ability.</div></div>","PeriodicalId":14160,"journal":{"name":"International Journal of Naval Architecture and Ocean Engineering","volume":"18 ","pages":"Article 100764"},"PeriodicalIF":3.9,"publicationDate":"2026-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147849561","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"A method for generating a 3D environmental map using a stereo camera for autonomous berthing of an unmanned surface vehicle","authors":"In-Chang Yeo ,&nbsp;Myung-Il Roh ,&nbsp;Yun-Sik Kim","doi":"10.1016/j.ijnaoe.2026.100758","DOIUrl":"10.1016/j.ijnaoe.2026.100758","url":null,"abstract":"<div><div>With recent advancements in maritime technology and the increasing use of USVs (Unmanned Surface Vehicles), the importance of precise, safe autonomous berthing technology for realizing fully autonomous navigation is emerging. Currently, LiDAR (Light Detection And Ranging), commonly used for USVs, is expensive, while electronic charts have limitations in reflecting the real-time dynamic environment. To overcome these limitations, this study proposes a method for generating a 3D environmental map for autonomous berthing of USVs using a low-cost stereo camera that operates robustly in maritime environments. The core novelty of this study lies in the design of a ‘maritime-specific unified filtering pipeline’ rather than a simple combination of existing deep learning models. Initially, a 2.5D depth map and corresponding masks were generated using vision foundation models to extract robust features in textureless maritime environments. Subsequently, the proposed multi-stage postprocessing pipeline, integrating geometric constraints based on camera parameters, SOR (Statistical Outlier Removal), and voxel-grid downsampling, was applied. This pipeline fundamentally transforms the unstable raw outputs of deep learning models into deterministic sensor data, represented as highly reliable 3D point clouds, by effectively eliminating physically impossible data and ghost obstacles. To verify the effectiveness of the proposed method, virtual environments precisely simulating the real world were constructed. The comparative results showed that FoundationStereo, unlike models such as CREStereo (Cascaded REcurrent Stereo) and Depth Anything V2, demonstrated superior performance in precisely restoring fine structures, such as ship masts, and complex distant skylines without distortion. Specifically, the proposed method achieved MAEs (Mean Absolute Errors) of 0.12 m, 0.11 m, and 0.08 m for 3D point positions across three scenarios, representing reductions of up to 94.62% compared to the comparative methods. Furthermore, the generated 3D environmental map was converted into a 2D BEV (Bird's-Eye-View) map, confirming that the USVs can intuitively perceive the horizontal positional relationships of obstacles and utilize them for route planning.</div></div>","PeriodicalId":14160,"journal":{"name":"International Journal of Naval Architecture and Ocean Engineering","volume":"18 ","pages":"Article 100758"},"PeriodicalIF":3.9,"publicationDate":"2026-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147538532","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"A structural response prediction of multi-linked floating offshore structures for digital twin implementation using Krylov subspace-based model order reduction","authors":"Kichan Sim ,&nbsp;Kangsu Lee","doi":"10.1016/j.ijnaoe.2026.100769","DOIUrl":"10.1016/j.ijnaoe.2026.100769","url":null,"abstract":"<div><div>Offshore structures are generally designed based on conservative safety factors and operated. However, due to the uncertainty of ocean environment in actual operations, ensuring structural safety is challenging. In particular, unexpected extreme wave loads, structural degradation, and operational accidents can lead to structural damage, making it essential to implement digital twin technology capable of real-time structural health monitoring and prediction. In this study, a digital twin model for predicting the structural responses of floating offshore unit structures was developed using the Krylov subspace-based model order reduction method. The system matrix and regular wave load vectors for each frequency component were constructed based on fluid-structure coupled analysis. And snapshot wave load vectors were generated by superposing frequency components, which were then projected onto the Krylov subspace along with the system matrix to build a reduced order model. And the irregular wave loads from measured wave elevation were constructed by estimating the frequency components through spectral analysis. These reconstructed wave loads were subsequently applied to simulate the structural responses using the reduced order model. The prediction accuracy of reduced order model was evaluated by comparing predicted results with numerical simulations and measured data through model test. As a result, the reduced order model achieved approximately 99% prediction accuracy using over 10 degrees of freedom compared to the full order model, while also offering hundreds times faster simulation speed. In addition, comparison with model test showed that the prediction accuracy improved as more frequency components were used to construct the wave loads, achieving a maximum accuracy of 96.7%.</div></div>","PeriodicalId":14160,"journal":{"name":"International Journal of Naval Architecture and Ocean Engineering","volume":"18 ","pages":"Article 100769"},"PeriodicalIF":3.9,"publicationDate":"2026-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147995234","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"A fine-grained behavior classification method for oil tankers based on bidirectional long short-term memory network","authors":"Zhaojin Yan,&nbsp;Kai Shi,&nbsp;Rong He,&nbsp;Pan Ye,&nbsp;Yuxuan Wang","doi":"10.1016/j.ijnaoe.2026.100749","DOIUrl":"10.1016/j.ijnaoe.2026.100749","url":null,"abstract":"<div><div>The Gulf of Mexico, a globally important oil tanker passage, presents a highly complex maritime traffic environment that imposes stringent requirements on supervision and early risk warning. Traditional monitoring methods have limitations in identifying complex behavioral patterns of ships. To address this gap, this study leverages Automatic Identification System (AIS) data to construct a fine-grained behavior recognition model for oil tankers based on a Bidirectional Long Short-Term Memory (BiLSTM) network. First, systematic AIS data preprocessing methods are proposed to correct anomalies and interpolate missing values, thereby improving data integrity and reliability. Second, using navigation knowledge constraints and trajectory features, nine types of oil tanker behaviors are manually annotated, including straight-line acceleration, straight-line deceleration, high-speed cruising (speed &gt;8 knots), low-speed cruising (speed ≤8 knots), accelerating turn, decelerating turn, constant-speed turn, berthing, and anchoring, thus establishing a high-quality, fine-grained behavioral dataset. Finally, the BiLSTM network is introduced to build a recognition model capable of classifying these behaviors with high accuracy. An empirical study in the Gulf of Mexico shows that the proposed model achieves an overall recognition accuracy of 98.27%. F1-scores for key behaviors such as anchoring, berthing, and high-speed cruising all exceed 0.98, confirming the model's effectiveness for practical maritime supervision. Compared with the multi-layer perceptron (MLP), LSTM, and temporal fusion transformer (TFT) models, the BiLSTM model achieves the highest scores in both Macro-F1 (0.936) and Weighted-F1 (0.981), thereby demonstrating the optimal performance in oil tanker behavior classification. The proposed framework provides reliable support for abnormal ship behavior recognition and intelligent maritime supervision, with potential for extension to other vessel types and high-risk sea areas.</div></div>","PeriodicalId":14160,"journal":{"name":"International Journal of Naval Architecture and Ocean Engineering","volume":"18 ","pages":"Article 100749"},"PeriodicalIF":4.4,"publicationDate":"2026-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148735611","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Structural consequences of rib reduction in marine lifting lugs: A nonlinear FEA-based performance and failure mode assessment","authors":"Joo Shin Park,&nbsp;O-Hyun Kwon,&nbsp;Jung-Goo Park,&nbsp;Jung Kwan Seo","doi":"10.1016/j.ijnaoe.2026.100782","DOIUrl":"10.1016/j.ijnaoe.2026.100782","url":null,"abstract":"<div><div>This study presents a comparative mechanics-based assessment of rib reduction in standardized marine lifting lugs to support lightweight and structurally efficient design. A nonlinear finite element analysis (FEA) framework, supported by full-scale tensile validation of a representative LA50 reference specimen, was used to examine the structural response of the LA, LV, and LE lug series under a representative wire angle. Reducing the number of reinforcing ribs from four to two resulted in capacity-dependent strength loss, a reduction in analysis-based derated allowable load of up to approximately 40% within the investigated cases, and a transition from ductile deformation to instability-sensitive collapse dominated by web buckling. The study also discusses an analysis-based wire-angle derating interpretation for rib-reduced configurations within the investigated geometry, material, and boundary-condition assumptions. Integrated analyses with representative ship-block models indicate that selected rib-reduced designs may have limited influence on surrounding structures. The results provide a validation-supported comparative basis for understanding rib efficiency, stiffness degradation, and failure-mode transition in standardized lifting lugs, and they support future development of more performance-informed lightweight design practices.</div></div>","PeriodicalId":14160,"journal":{"name":"International Journal of Naval Architecture and Ocean Engineering","volume":"18 ","pages":"Article 100782"},"PeriodicalIF":4.4,"publicationDate":"2026-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148539345","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Study on the horizontal ultimate bearing capacity of offshore wind turbine monopile foundations in sand","authors":"Hongwang Ma ,&nbsp;Tong Wu","doi":"10.1016/j.ijnaoe.2026.100748","DOIUrl":"10.1016/j.ijnaoe.2026.100748","url":null,"abstract":"<div><div>The horizontal ultimate bearing capacity (HUBC) is a crucial design parameter of monopile foundations, significantly impacting their safety and economic efficiency. It is typically determined by theoretical or empirical approaches in which the monopile is assumed to be rigid. However, actual monopiles are generally semi-rigid. This paper presents a study on the HUBC of both rigid and semi-rigid piles by means of theoretical analysis and numerical simulations. A correction factor is derived, and a general formula is established for the calculation of the correction factor. Validation is performed using the OC3 5 MW monopile as a case study. Upon incorporating the effect of elastic deformation, the HUBC decreases from 63,290 kN to 42,683 kN, achieving a reduction rate of 32.6 %. The research findings demonstrate that for large-diameter piles, the rigid pile assumption is no longer valid, and the reduction effect arising from the elastic deformation of the pile shaft must be taken into consideration. The method proposed in this study can be directly applied to preliminary engineering design or code verification, thereby realizing the rapid and accurate estimation of the HUBC of wind turbine monopile in sand.</div></div>","PeriodicalId":14160,"journal":{"name":"International Journal of Naval Architecture and Ocean Engineering","volume":"18 ","pages":"Article 100748"},"PeriodicalIF":3.9,"publicationDate":"2026-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147396767","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Long-term ship trajectory prediction using a transformer with inverted attention and feature augmentation","authors":"Sangseok Lee,&nbsp;Han Jin Lee,&nbsp;Wonhee Lee","doi":"10.1016/j.ijnaoe.2026.100744","DOIUrl":"10.1016/j.ijnaoe.2026.100744","url":null,"abstract":"<div><div>Maritime transportation is essential for global trade, with the increasing ship traffic necessitating accurate trajectory prediction for enhanced safety and efficiency. In this study, a transformer-based architecture is proposed for long-term ship trajectory prediction. Feature augmentation is performed by deriving kinematic and directional variables from raw AIS data, and trajectory clustering is applied using dynamic time warping. An inverted attention mechanism is employed, to compute the attention across variables rather than temporal positions, thereby enhancing scalability in high-dimensional settings and enabling explicit modeling of variable dependencies. The encoded representations are mapped to the prediction horizon through a multilayer perceptron decoder. Comprehensive experiments on AIS trajectory datasets demonstrated that the proposed framework attains higher accuracy in both short- and long-term prediction tasks. The results indicate that the integration of feature augmentation and inverted attention enhances predictive accuracy, robustness, and generalization for maritime trajectory prediction.</div></div>","PeriodicalId":14160,"journal":{"name":"International Journal of Naval Architecture and Ocean Engineering","volume":"18 ","pages":"Article 100744"},"PeriodicalIF":3.9,"publicationDate":"2026-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147396771","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Development of a novel model testing methodology for integrated performance evaluation of a wave energy converters of floating type","authors":"Yoon-Jin Ha,&nbsp;Jeong-Seok Kim,&nbsp;Kilwon Kim,&nbsp;Kyong-Hwan Kim,&nbsp;Ji-Yong Park","doi":"10.1016/j.ijnaoe.2025.100737","DOIUrl":"10.1016/j.ijnaoe.2025.100737","url":null,"abstract":"<div><div>In this study, a new model-testing methodology, termed the Real-Time Hybrid Model Test, was developed to evaluate the integrated performance of floating-type wave energy converters (FWECs) in a wave basin. The proposed technique incorporates a full-scale hydraulic power take-off (PTO) system, generator, and power conversion system (PCS), as well as a Maximum Power Point Tracking (MPPT) control algorithm to maximize electrical power extraction. In the Real-Time Hybrid Model Test, the measured motion of the FWEC model at each sampling interval is converted to full scale and supplied as input to a real-time full-scale simulation. Based on this input, the full-scale hydraulic PTO, generator, and PCS responses—including the MPPT control actions—are numerically computed. The resulting full-scale PTO load is then dynamically scaled down and applied to the physical model using a linear-motor actuator, thereby establishing a closed-loop interaction between the physical model and the numerical PTO system. The motion Response Amplitude Operators (RAOs) and the optimal hydraulic PTO force were evaluated in regular waves, and the performance of the proposed technique was further assessed in white-noise waves by comparing the results with those obtained from a conventional model test. The experimental results demonstrate that the Real-Time Hybrid Model Test provides a reliable and effective framework for evaluating FWECs, offering significant advantages in reproducing realistic PTO dynamics during physical model experiments.</div></div>","PeriodicalId":14160,"journal":{"name":"International Journal of Naval Architecture and Ocean Engineering","volume":"18 ","pages":"Article 100737"},"PeriodicalIF":3.9,"publicationDate":"2026-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146034414","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"A method for pipe auto-routing using an LLM-based expert system","authors":"Min-Chul Kong,&nbsp;Myung-Il Roh,&nbsp;In-Su Han,&nbsp;Seong-Won Choi,&nbsp;Jeongyeon Kim,&nbsp;Dong-Woo Kim","doi":"10.1016/j.ijnaoe.2026.100796","DOIUrl":"10.1016/j.ijnaoe.2026.100796","url":null,"abstract":"<div><div>Pipe routing in shipbuilding and offshore engineering is a complex spatial planning task that must satisfy numerous functional requirements, including interference avoidance, maintainability, and operational accessibility. While algorithmic approaches like A* pathfinding frame this as a cost-minimization problem, determining appropriate penalty weights for factors such as path length, bend count, and deck proximity remains a highly subjective, labor-intensive process. Designers typically must adjust these parameters through continuous trial and error to meet project-specific constraints. To resolve this, this study introduces an automated pipe routing method integrated with a multi-agent LLM (Large Language Model) expert system. The proposed framework formalizes expert design knowledge—ranging from hard geometric constraints to soft layout preferences—into structured object and relation rules. A dedicated ‘result analysis agent’ qualitatively evaluates the algorithmic routing outcomes against these rules, while a ‘weight-tuning agent’ dynamically adjusts the A* cost weights based on the diagnostic feedback and historical iteration data. This closed-loop architecture enables the system to self-diagnose and iteratively re-optimize routes without human intervention. Verification tests demonstrate that the LLM accurately interprets spatial constraints and progressively refines routing quality. Over three iterations, the number of bends was reduced by approximately 14% and the grouping metric by approximately 73%, while the total path length increased by only about 8%, with each iteration requiring roughly 1 min of computation. Additionally, the study confirms the practical feasibility of utilizing an on-premise open-source LLM to address industrial data security requirements. By successfully embedding expert reasoning directly into the optimization loop, this approach provides a highly adaptable, consistent, and automated framework for ship piping design.</div></div>","PeriodicalId":14160,"journal":{"name":"International Journal of Naval Architecture and Ocean Engineering","volume":"18 ","pages":"Article 100796"},"PeriodicalIF":4.4,"publicationDate":"2026-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148776829","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}