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29 December 2025, Volume 12 Issue 4 Previous Issue   

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Introduction to Military Model Making: Taking the Type 05 Amphibious Armored Assault Vehicle as an Example GUO Sixing, LI Yuting, LI Jiaqiang, et al 2025, 12 (4):  1-9.  DOI: 10.12087/oeet.2095-7297.2025.04.01 Abstract ( 169 )   PDF (4871KB) ( 42 )   By documenting the entire process of building a scale model of the 05 amphibious assault vehicle—from information gathering and 3D modeling to final fabrication—this project illustrates the distinctive value of military modeling in naval and military-engineering education. It seeks to spark students' interest in ocean engineering and, ultimately, to cultivate the interdisciplinary talent required by China's national strategy of strengthening the country through human capital development. The work also serves as an important popularscience resource for military engineering education. Related Articles | Metrics

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Naval Battle Model Production: A Conceptual Naval Battle Model Based on Aircraft Carrier Formations GUO Sixing, SHOU Hai, CHEN Zehan, et al 2025, 12 (4):  10-17.  DOI: 10.12087/oeet.2095-7297.2025.04.02 Abstract ( 202 )   PDF (5239KB) ( 38 )   Against the backdrop of the evolving international situation and the continuous enhancement of naval combat capabilities, this project takes hypothetical future naval battles as a blueprint to design, fabricate, and demonstrate a scaled-down model of a partial naval battle scenario. This paper aims to demonstrate China's growing naval equipment capabilities and its future combat processes by creating scaled-down partial naval battle models and supporting wargames. This initiative is designed to popularize knowledge about the combat processes of aircraft carrier battle groups among students and strengthen patriotic education. Related Articles | Metrics

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Structural Design of an Offshore Floating Base under a Modular Concept ZHANG Shutian, CHEN Zehan, TIAN Yutao, et al 2025, 12 (4):  18-31.  DOI: 10.12087/oeet.2095-7297.2025.04.03 Abstract ( 214 )   PDF (6327KB) ( 50 )   To address the issues—high construction costs, limited flexibility, and difficulty in meeting the maintenance demands of large naval vessels such as aircraft carriers—associated with traditional ultra-large floating docks, this paper proposes a modular, self-propelled, multi-functional offshore floating-base structure based on the concept of very large floating structures (VLFS). This platform consists of multiple small floating dock modules, each equipped with its own lifting, self-propulsion and dynamic-positioning systems. These modules can be flexibly combined according to mission requirements to form an ultra-large floating operation platform with comprehensive support capabilities. This paper elaborates on its overall architecture, buoyancy design, power configuration, ship guidance system, and structural connection scheme. Furthermore, its structural safety and operational feasibility are validated by means of hydroelastic-response analysis and transverse-strength assessment. This design provides an important reference for the future engineering implementation and educational application of mobile offshore bases. Related Articles | Metrics

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Jacket Horizontal Non-Skidway Construction and SPMT Loadout Technology LI Bing 2025, 12 (4):  32-37.  DOI: 10.12087/oeet.2095-7297.2025.04.04 Abstract ( 188 )   PDF (8901KB) ( 41 )   The non-skidway construction of jackets and self-propelled modular transporter (SPMT) loadout technology has features such as not occupying skidway resources, not requiring sliding equipment, a fast loadout speed, requiring less prefabricated process equipment, and the ability to reuse it. Compared to conventional construction methods, this technology has better economic advantages and can increase the production capacity of the construction site for jackets. Currently, there are no relevant engineering cases for reference in China. In this regard, taking a hundred-meter jacket project that uses this technology as an example, the critical techniques of this engineering case are systematically introduced from aspects such as process equipment design, foundation settlement prevention, and SPMT loadout plan design. This case can provide certain technical support for the subsequent application of this technology in China. Related Articles | Metrics

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Analysis of Cable Tension and Cable Shape of Emergency Buoy Rescue System for Manned Submersible XING Dan, QU Wenxin, HU Zhonghui, et al 2025, 12 (4):  38-43.  DOI: 10.12087/oeet.2095-7297.2025.04.05 Abstract ( 173 )   PDF (1490KB) ( 39 )   When a manned submersible fails to surface in an emergency, the emergency buoy acts as the final safeguard, establishing a connection between the submersible and the rescue vessel on the surface, providing both position indication and a tow line for subsequent rescue operations. The rationality and effectiveness of the emergency buoy design are particularly critical. In this paper, a mathematical model of the cable of emergency buoy rescue system is established, and the cable shape and tension distribution of the emergency buoy rescue system of manned submersible under different working conditions are calculated and analyzed. The variation patterns of cable shape and tension are obtained for different deployment depths of the emergency buoy, different net buoyancies, and different cable diameters. This study can provide a reference for the design of manned submersibles. Related Articles | Metrics

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Commissioning and Application of Jacket Pile Gripper System for Offshore Wind Power Project BI Hangming 2025, 12 (4):  44-48.  DOI: 10.12087/oeet.2095-7297.2025.04.06 Abstract ( 171 )   PDF (1096KB) ( 33 )   With the comprehensive green transformation of economic and social development and the pursuit of China's “dual carbon” targets， offshore wind power project development is gaining momentum and playing an increasingly important role and finding wide application in the global energy transition. Taking a European offshore wind power jacket foundation project as an example， this paper presents the commissioning process of the jacket pile gripper， highlights the differences in gripper commissioning between offshore wind and offshore oil and gas projects， describes the associated test equipment and materials， and summarizes key operational precautions， thus providing a useful reference for similar offshore wind developments. Related Articles | Metrics

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Experimental Study on the Dynamic Response Characteristics of Buoys in Floating Wind Turbine Mooring Systems under Current Loads LI Xiaoyong, ZHANG Hang, JI Weidong, et al 2025, 12 (4):  49-54.  DOI: 10.12087/oeet.2095-7297.2025.04.07 Abstract ( 198 )   PDF (3766KB) ( 33 )   The mooring system of floating offshore wind power structures is a key component ensuring their long-term stable operation. In recent years， to enhance mooring performance and reduce construction and maintenance costs， optimized mooring system designs incorporating auxiliary buoys have attracted widespread attention. Based on a comprehensive review of related studies both domestically and internationally， this paper focuses on the dynamic response characteristics of buoys under ocean current effects. A series of current-induced load experiments were conducted in a circulating water channel using a 1∶25 scale buoy model. The pitch angle of the buoy and the mooring line tension were measured under different current velocities， and the variation law of the current load coefficient with current velocity was analyzed. The experimental results indicate that the buoy exhibits significant current-induced vibrations at high current speeds. The mooring tension shows a continuous increase in the horizontal direction， while in the vertical direction， the tension demonstrates non-monotonic variation due to vibration effects. The obtained dimensionless current load coefficient ranges from 1.056 to 1.538. These results provide essential parameters for the design of buoys in floating wind turbine mooring systems， thereby improving their safety and cost-effectiveness. Related Articles | Metrics

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Research and Application of Emergency Pressure Recharging Technology for ROV in Subsea Production System ZOU Jianwen 2025, 12 (4):  55-63.  DOI: 10.12087/oeet.2095-7297.2025.04.08 Abstract ( 147 )   PDF (7800KB) ( 36 )   This paper addresses the abnormal pressure drop in the low-pressure loop chemical injection of a subsea production system in the South China Sea by proposing and implementing a comprehensive emergency pressure recharging solution for the first time. Through systematic solution selection， stabplate modification， and the design of a dedicated pressure recharging device， combined with validated onshore simulation test， the offshore emergency pressure recharging operation was successfully completed. Practice demonstrates that this emergency pressure recharging solution effectively maintains system pressure stability， avoids the risk of automatic wellhead shutdown， and ensures the safe and continuous operation of the subsea production system. This study not only resolves a practical engineering issue but also provides valuable technical methods and practical experience for handling similar pressure abnormal in subsea production systems， and is of great significance for ensuring the reliability and safety of subsea production systems. Related Articles | Metrics

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Standard Comparison between Mechanical Gauging and Pressure Testing for Subsea Pipelines CAO Juhang, ZHANG Jie, LI Jian, et al 2025, 12 (4):  64-71.  DOI: 10.12087/oeet.2095-7297.2025.04.09 Abstract ( 170 )   PDF (2741KB) ( 37 )   Given the significant importance of mechanical gauging and pressure testing for submarine pipelines in offshore pipeline construction， this study focuses on reviewing the requirements for mechanical gauging and system pressure testing as outlined in the ASME， API， and DNV standards. By explaining the principles of submarine pipeline mechanical gauging， the calculation methods for gauge-plate diameters under different standards are analyzed. Based on the principles of pipeline pressure testing， it is clarified that test pressure and holding time are the two critical parameters in pipeline pressure testing. The magnitude of the test pressure depends on the size of the defects that need to be detected during the test. The duration of holding time is influenced by multiple factors， including the size of leaks， pipeline volume， and pipeline diameter. Although ASME， API， and DNV share similar general principles for submarine pipeline pressure testing， differences exist in the selection of test pressure and holding time， which necessitates an analysis of their applicability in engineering practice. Related Articles | Metrics

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Feasibility Study on the Application of Free-Fall Lifeboats on Cylindrical FPSO MA Huihao, TIAN Feng, LV Jinbo, et al 2025, 12 (4):  72-76.  DOI: 10.12087/oeet.2095-7297.2025.04.10 Abstract ( 183 )   PDF (1887KB) ( 34 )   A preliminary selection of the lifeboat type was made based on design specifications， the environmental conditions of the Liuhua oil and gas field project and the specific parameters of the cylindrical floating production storage offloading（FPSO) and lifeboat device were introduced. The motion of the lifeboat during the release process was analyzed， and based on the application of lifeboats on SEVAN cylindrical FPSO， it was demonstrated that the application of free-fall lifeboats on Liuhua's cylindrical FPSO is feasible. Related Articles | Metrics

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Safety Assessment of Large Structures Hoisting and Unloading from Vessels NI Pinghu, CHEN Silin, FAN Xiangbin, et al 2025, 12 (4):  77-82.  DOI: 10.12087/oeet.2095-7297.2025.04.11 Abstract ( 201 )   PDF (4300KB) ( 38 )   With the development of the offshore construction industry， many 100-ton large structures need to be transported to the assembly site by sea. In the unloading and transfer process， the barge is affected by the wind， waves， and currents， which will produce six-degree-of-freedom motion， so that the suspended load moves relative to the ground， causing the suspended load to sway， which affects the crane operation， resulting in operational inefficiencies and a series of potential safety hazards. In this paper， for hoisting and unloading of large structures， numerical simulation is used to analyze the barge movement and the dynamic characteristics of the lifting process， to assess in advance the safety of the operating envelope and sling forces throughout the operation， and to propose countermeasures for the main safety risks， in order to provide reference for the construction of subsequent similar projects. Related Articles | Metrics

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Latest Progress and Perspective in Analysis Technologies of Floatover Installation System QIN Licheng, LIANG Xuexian, FANG Xukai, et al 2025, 12 (4):  83-95.  DOI: 10.12087/oeet.2095-7297.2025.04.12 Abstract ( 250 )   PDF (8149KB) ( 34 )   With the rapid development of offshore engineering technology， offshore platforms are developing towards large-scale and integrated， which also puts forward higher requirements for offshore installation technology， and floatover installation technology also comes into being under this background. It is of great significance for the design and implementation of offshore platform installation to carry out sufficient research on the floatover system. This paper introduces the numerical and experimental modeling and analysis of the floatover system， including the hydrodynamic analysis， the modeling of the load buffer device， and the research of the nonstationary nonlinear multi-body system. Some views on future development trends are also provided. Related Articles | Metrics

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Key Nodes in the System Commissioning of Offshore Oil Platforms ZHANG Chun 2025, 12 (4):  96-103.  DOI: 10.12087/oeet.2095-7297.2025.04.13 Abstract ( 233 )   PDF (2452KB) ( 35 )   The commissioning of an offshore oil and gas production platform system is a critical task preceding mechanical completion of both onshore fabrication and offshore installation. The thoroughness and outcomes of the commissioning work will have a direct impact on the safe operation of the oil and gas fields. This article primarily addresses the preparatory work and overarching principles prior to system commissioning， alongside the key tasks that require focused attention during the commissioning phase. The primary framework encompasses platform power transmission and reception， crude oil generator commissioning， EMS (emergency management system) commissioning， central control logic testing， and the commissioning of water circulation and other utility systems. These cover areas such as power， process， utilities， and instrumentation controls. It provides a detailed elaboration on the pre-commissioning activities pertinent to conventional offshore oil and gas production platforms， the main elements of the commissioning process， and the objective of employing commissioning to promote construction progress and quality， thereby ensuring the seamless completion of the commissioning work. Related Articles | Metrics

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Study on Oil Flushing Process and Method Optimization WANG Ziyang, WANG Xiaohua, GUO Chongxiao, et al 2025, 12 (4):  104-115.  DOI: 10.12087/oeet.2095-7297.2025.04.14 Abstract ( 182 )   PDF (4786KB) ( 31 )   In the offshore engineering construction， the cleanliness of equipment and instrumentation pipelines plays a vital role in the safe and long-lasting operation of production platforms. Oil flushing as an efficient pipeline cleaning method， the existing studies have focused on analyzing the oil-flushing process itself， while paying little attention to improving flushing efficiency or optimizing the methodology. In this manuscript， the oil flushing equipment， construction process， factors affecting oil flushing efficiency are studied. Then the characteristics of series and parallel flushing methods are compared. Finally， an oil flushing device that can be used in multiple parallel flushing is proposed， and numerical simulation of the oil flow characteristics in the device is carried out based on ANSYS Fluent. According to the results of the simulation， three optimized forms of single column structure， symmetric structure and staggered structure are proposed， and the flow distribution characteristics of the three optimized structures are compared with those of the original structure. The research results show that the flow distribution consistency of the oil in the form of symmetric structure is the highest， and its four branch flow basically meets the flow requirement of 43.73L/min， which can realize multiple parallel flushing. Related Articles | Metrics

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Study on the Stability of Riprap Protection at Pile Foundations in Uniform Flow QIN Yaling, YANG Xinzhu, CHEN Xiaohui, et al 2025, 12 (4):  116-123.  DOI: 10.12087/oeet.2095-7297.2025.04.15 Abstract ( 172 )   PDF (2997KB) ( 36 )   Riprap protection is regarded as one of the most widely used methods for erosion protection of hydraulic foundations such as bridge piers in water. To accurately predict the scouring depth at the pile foundation after the implementation of riprap protection not only provides a calculation tool for the riprap amount for pile foundation maintenance engineering design， but also provides a means for the safety assessment of pile foundation for riprap protection design. This article experimentally explores the variation characteristics of the maximum scouring depth in the riprap layer at the pile with factors such as pile diameter， riprap particle size， flow depth， and approach flow velocity， respectively. The flume experiments show that in order to improve the stability of the riprap layer， the thickness of the riprap layer should beat least as large as the bedform height， and the range of the riprap layer should be at least larger than 5 times the pile diameter to avoid bedform destroy. Under these conditions， the larger the size of the riprap， the better the protective effect would be， and the larger the pile diameter， the greater the scour depth would be. Finally， a formula for calculating the maximum scouring depth after riprap protection is proposed， which would provide reference for future engineering design for riprap protection. Related Articles | Metrics

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Research on Key Technologies of Offshore Construction for Mooring Systems of Floating Wind Turbines CHEN Wei, WANG Zhizhou, WU Hehe 2025, 12 (4):  124-132.  DOI: 10.12087/oeet.2095-7297.2025.04.16 Abstract ( 147 )   PDF (13568KB) ( 40 )   This paper conducts research on the offshore construction of floating wind turbine mooring systems， identifies key issues in the construction process， addresses offshore construction challenges， ensures safe and efficient installation， achieves high-quality deployment， and provides technical references for domestic floating wind power projects. Focus on the four key issues of precise penetration of suction anchors， accurate laying of anchor chains， rapid reconnection of floating bodies， and precise tensioning of moorings， conduct comprehensive process research， formulate construction plans relying on full-slewing crane ships， and make detailed technical preparations. The precise penetration of the suction anchors was achieved， and the anchor chains were laid along the route without torsion. Finally， the position of the floating body， draft depth， and anchor chain tension all met the design requirements， and the mooring system operated stably. The construction technology formed by the research can ensure the offshore construction of floating wind turbines， save project costs， and improve the domestic floating wind power construction. Related Articles | Metrics

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Fatigue Life Analysis of Steep-Waveform Flexible Riser with Full Coupling FENG Meng, Liu Xinghua, YANG Shuai, et al 2025, 12 (4):  133-140.  DOI: 10.12087/oeet.2095-7297.2025.04.17 Abstract ( 162 )   PDF (6251KB) ( 44 )   During the long-term service of flexible risers， problems such as permeation in the annular layer and interlayer friction may occur. Under alternating loads， the fatigue damage of the tensile armor wire will accelerate. This paper conducts a safety assessment for steep-waveform flexible risers. By establishing a global-local-failure finite element model that takes into account interlayer friction and corrosion effects， the dynamic response and fatigue life of the flexible risers under the full coupling model are mainly studied. The results show that both interlayer friction and corrosion effects will affect the in-service life of the flexible risers. Interlayer friction mainly increases the stress amplitude of the tensile armor wire， while the corrosion effect not only reduces the cross-sectional size but also requires the selection of the corresponding S-N curve due to the presence of the corrosive environment. The corrosion effect has a greater impact on the fatigue life. Therefore， when conducting in-service riser assessment， interlayer friction and corrosion fatigue issues should be fully considered， and effective measures should be taken to manage the integrity of the flexible risers. Related Articles | Metrics