In order to understand the applicability of the speed correction method of the ITTC 2021, the experimental requirements and correction process of the speed correction method of this method during the test of ship speed are introduced and compared with those of the ISO 15016∶2015. Speed correction programs for the two methods are developed through programming based on the principle of speed correction. The trail data of three typical ship types are then analyzed by using the two correction methods, summarizing the effects of the two correction methods on the correction results under different environmental factors such as wind, wave, tide, temperature, density, and water depth. The results show that the correction method of the ITTC 2021 is more reasonable than that of the ISO 15016∶2015. And the resulting speed corrected by the ITTC 2021 method is slightly higher than that by the ISO 15016:2015 correction method for these three ship types, while the newly added correction method for the added resistance in waves is the main factor causing the difference of the analysis results.

The structural analysis of the Ro-Ro access demands further investigation due to its complexity and the applicability problems in the requirements of the vehicle deck size of the China Classification Society Rules for Classification of Sea-going Steel Ships. The plate, beam structure and primary supporting members of the Ro-Ro access are studied to establish the descriptive requirements of the vehicle deck plate thickness and the stiffener scantlings by using the theoretical formula derivation and the numerical fitting method. At the same time, the direct calculation requirements for the primary supporting members of the access that meet the unified requirements of the International Association of Classification Societies (IACS) and cover all kinds of loads are formed and then verified through case calculations. The results show that the optimized descriptive requirements and direct calculation requirements have good applicability. This study is of great significance for improving the safety and lightweight level of the Ro-Ro access structure design.

Since the successful application of the IMO's Goal-Based Ship Construction Standard (GBS) in the hull structure rules for oil tankers and bulk carriers by the International Association of Classification Societies (IACS), the GBS has gradually been promoted to various maritime fields and the development of specifications for all types of seagoing vessels. The state-of-the-art of the GBS in the research of rules for seagoing vessels at home and abroad is summarized to deeply analyze the technical characteristics of the hull structure rules based on the GBS. A framework is accordingly proposed for adoption of the GBS in the hull structure rule system of the China Classification Society (CCS).

The optimization of ship resistance is an important method to reduce the fuel consumption and improve the ship energy efficiency. The wind resistance of container ships accounts for a much larger proportion than that of other ships, which is a nonnegligible important part. The installation of a fairing at the bow has a significant effect on the wind resistance of the container ship. The total resistance and the wind resistance of a fully loaded container ship sailing at the design speed are calculated by using the computational fluid dynamics (CFD) technology. The mechanism of the resistance reduction using the fairing is analyzed by studying the reduction of the wind resistance and the total resistance due to the fairing when facing the wind at different wind speeds. The fairing can guide the flow and delay the flow separation, which effectively reduces the pressure resistance between the front and rear of the ship. The reduction of the wind resistance due to the fairing is stable at about 40%. The reduction of the total resistance due to the fairing gradually increases with the increase of the wind speed, and the resistance reduction can reach 2.91% under the wind speed of scale 8. The results can provide references for the practical design application and resistance evaluation of the fairing of container ships.

Aiming at the energy conservation and emission reduction of the ship, a marine solar photovoltaic flexible support which can be laid on the deck has been designed based on the parameters and operation conditions of the KVLCC2, and the vibration response characteristics are analyzed. The effects of the wind load and the pitch and heave of the ship on the vibration response characteristics of the flexible support are studied by using the fluid-structure interaction decoupling calculation method. The results show that the amplitude and the average internal stress of the steel cable are the largest under the pitch condition, which have an adverse effect on the flexible support, followed by the pitch and heave conditions, and the lowest under the heave condition. The maximum structural stress occurs at the boundary of the steel cable support, and the plastic deformation will occur earliest if the external load increases further. The average stress and amplitude of the steel cable in the middle of the flexible support are the largest, and fatigue failure may occur under the cyclic stress and strain. The above conclusions provide a basis for the design, manufacture and daily use of the marine solar photovoltaic flexible support.

A software has been developed to predict the inherent longitudinal vibration characteristics of the ship shafting. The software is developed using the QT platform, with the core solver written in MATLAB and the solution algorithm using the Holtz method. The results are compared and verified with the simulation results of ANSYS and the longitudinal vibration calculation results of an actual shafting system. On this basis, the developed software is used to discuss the variation of the longitudinal vibration characteristics of the shafting under different shafting properties. The results show that the properties affecting the inherent longitudinal vibration characteristics of the shafting mainly include the crank radius, crank thickness, longitudinal stiffness of thrust bearings and material elastic modulus. The relevant research results can provide references for the vibration and noise reduction of the ship shafting.

The contra-rotating rudder propeller has the characteristics of good maneuverability and high propulsion efficiency, which is usually applied in ship types, such as science research vessels and offshore engineering ships. The open-water characteristics of the contra-rotating rudder propeller are simulated by using the improved delayed detached eddy simulation (IDDES) method, with comparative analyses based on the model test results. The results show that the numerical simulation errors of the thrust coefficient and the torque coefficients of the propulsion unit at the design point are within 3%. It is observed that the rudder angle has smaller impact on the open-water characteristics of the front propeller but larger impact on those of the aft propeller based on the open-water tests under different rudder angles. The transverse force of propulsion unit is 0 at the rudder angle of 2.5° in the current case. The influence of the strut on the tip vortex of the front propeller is studied through the cavitation model test. The cavitation is significantly enhanced when the tip vortex of the front propeller meets the blades of the aft propeller or the tip vortex of the aft propeller. Based on the interaction of all components of the contra-rotating rudder propeller, the induced velocity correction coefficient is introduced to transform the design of the blades of the contra-rotating rudder propeller into the design of the blades under the given incoming flow condition.

During the thermal launch operation of offshore launch platforms/ships, they will be subjected to the combined effects of rocket impact, wind, waves, and currents. Due to different arrangements of mooring systems, the motion response and mooring stress state of offshore launch platforms/ships are affected, which in turn affects the safety of the platform/ship-arrow. Therefore, this article explores the mooring arrangement of offshore launch ships under the coupling of multiple factors, including the arrangement of mooring point positions and changes in mooring line lengths, and their effects on the motion response and mooring stress state of offshore launch ships. Research has found that placing the mooring point below the waterline of the launch vessel and appropriately increasing the length of the mooring line will be more conducive to the conduct of offshore launch operations, providing technical references for the future layout of offshore launch vessel mooring systems.

5059 aluminum alloy has become the preferred choice for the ship structure due to its excellent mechanical properties and corrosion resistance. However, the current code lacks the S-N fatigue curve of the 5059 aluminum alloy, imposing difficulties on the fatigue evaluation of the 5059 aluminum alloy ship structure. The 5059 aluminum alloy and a typical marine welded joint are designed to carry out the fatigue tests at the room temperature and the low temperature (-35℃). The corresponding fatigue S-N curve is fitted by the least square method based on the test data. A finite element model of the specimen for fatigue test is established, and the stress obtained by the finite element analysis is extrapolated to obtain the hot spot stress. The fatigue life of the fatigue specimen is predicted by using the fitted S-N curve and compared with the result from the fatigue test. The results show that the proposed S-N curve of the 5059 aluminum alloy material and the welded joint can be used to predict the fatigue life of the ship structure under the low temperature environment.

The vortex-induced vibration (VIV) of a cylinder with mass ratio 2.6 and damping ratio 0.0036 at different reduced velocities has been numerically simulated based on the overset grid method. The amplitude, frequency ratio, wake vortex shedding modes and nonlinear characteristics of the VIV response are systematically analyzed. With the increase of the reduced velocity, the VIV response of the cylinder switches four times, but only once the phase difference between the transverse flow vibration response and the vortex force coefficient changes abruptly, which causes the wake vortex shedding mode to change from “2T” mode to “2P” mode. In addition, the velocity variation range of the VIV of the cylinder is smaller than its displacement variation range under any reduced velocities. When the reduced velocity is 4.0, the VIV of the cylinder is chaotic in both the streamwise and transverse directions. When the reduced velocity is 8.0, the VIV of the cylinder is also chaotic in the transverse direction, but still is self-limited. Under the other reduced velocities, the vibrations of the cylinder are regular and stable in the streamwise and transverse directions.

The positioning speed of the life buoys equipped on the ship in case of a shipwreck plays a great role in the efficiency and even the success rate of rescue. It is important to grasp the hydrodynamic characteristics of life buoys in waves for the positioning speed of the life saving. In this paper, in order to improve the navigation speed of life buoys, the hydrodynamic characteristics of self-develped integral self-propelled buoys are investigated with different trim angle and navigation speed under the still water and regular waves by numerical method. It is found that the drag force on self-propelled floats in still water and regular waves increases nearly linearly with the increase of sailing speed, and the drag force on regular waves is generally larger than that in still water. The motion response of a self-propelled float is further induced by the increase of the high-pressure region, the emergence of the low-pressure region, and the alternation of high- and low-pressure regions around the float by wave action. The motion response of the self-propelled floats is greatly affected by the draft, and the longitudinal oscillatory motion of the floats is more pronounced at smaller and larger initial drafts, while the vertical oscillatory motion of the self-propelled floats is more and more pronounced as the draft increases. The conclusions of the study can provide the necessary data support for the research and development of self-propelled floats.

An omnidirectional unmanned ship platform is designed based on four paddle wheels to address the problems of large turning radius of existing garbage cleaning ships, especially poor maneuverability in small and narrow waters. A kinematic model has been firstly established for the dynamic analysis of the ship. The paddle wheel is stably controlled by using the fuzzy adaptive proportional-integral-derivative (PID) control algorithm, combing with the real-time motion data of the direct current (DC) motor encoder. The experimental results show that the omnidirectional USV can achieve transverse, longitudinal and oblique motion without changing heading angle. The trajectory tracking accuracy is high, with an error of within 10 cm, and the actual trajectory conforms to the expected one. This ship has advantages such as zero turning radius and shallow draft, which is suitable for garbage cleaning in small narrow waters.

Hydroelastic experiment is an important method to investigate the hydroelastic response of ships. The state-of-the-art of the hydroelastic experiment of ships at home and abroad has been summarized, with focuses on the widely used segmented keel beam model, including the structural design, hydrodynamic module design, loading types and experimental result measurement. The applicability of different segmented keel beam models is then analyzed. The key technologies of the segmented keel beam model in the experimental design stage are summarized to provide the design indicators for the main contents based on the team experience, in order to provide references for the design of the hydroelastic experiment for ships.

Polar marine equipment is the main carrier for human participation in polar activities. The suggestions for the division of the polar marine equipment system are provided in the current study. The key directions for future polar marine equipment in China are found based on the historical development of China’s polar marine equipment and the comparative analysis of similar equipment types at home and abroad. Nine technical disciplines for polar ships are proposed and three major technical requirements are listed and elaborated by combining with the engineering research and development of heavy icebreakers. It can provide references for the research and development of relevant equipment technologies in China.

The advancement of computer performance and the development of artificial intelligence technology have promoted the transformation of the shipping industry towards intelligence, and more and more ships are equipped with intelligent systems. Ship intelligent systems can replace crew members to perform various repetitive and harsh work, and play a very important role in improving work efficiency and safety. With the development of ship intelligent systems, there are significant differences in the intelligence levels of different systems. It is necessary to assign reasonable tasks based on the evaluation level of intelligence so that intelligent systems can autonomously complete them. Therefore, accurately evaluating the ability of intelligent systems is very important. This article first outlines the current research status and significance of ship intelligent system level assessment, and then introduces and analyzes existing intelligent system level assessment methods. Next, a cobweb model based on “task + ability” for evaluating the intelligence level of ship intelligent systems is proposed, and finally, this cobweb model is employed to assess the level of intelligence of the intelligent system installed on a specific scientific research vessel.

Whether in times of war or peace, cross domain maritime transport activities are important actions related to national interests, and the ship formation configuration is a key issue that needs to be paid close attention to during the cross domain operations. A quantitative analysis method is used to model the interception of sea targets by the convoy vessel. The formation size and position of convoy vessels are analyzed when two ships are accompanied. The formation configuration conditions for the convoy vessel and carrier formations are obtained while ensuring interception of targets. Based on actual situations, key issues that need to be paid attention to in the formation configuration of cross domain carrier formations at sea are proposed. The conclusion not only provides qualitative but also focuses on quantitative decision-making support for the command of cross domain maritime transport operations.

Under the background of the first shipboard application of the medium voltage direct current (DC) integrated power system, the technical principles and characteristics of several high-power medium voltage DC test loads that were successfully developed in China recently are studied aiming at the mooring test load requirements of the large-capacity marine medium voltage DC power station. The performance of these test loads is then summarized and compared. Finally, suggestion of designing an energy-feedback combined load system is proposed together with the actual application conditions of the test loads in the shipyard mooring test and the development of the marine test loads. The test load function can be achieved while reasonably utilizing the energy generated during the power station test, in order to provide a preliminary scheme of the load system. It can provide theoretical references for the selection and application of the subsequent large-capacity medium voltage DC power station test load.

In order to meet the high requirements of vibration isolation index and layout of the engine room pump set for a quiet ship, the design of the regional vibration module of the engine room pump set of the ship is studied by utilizing the advantages of compact equipment layout, high space utilization and good vibration isolation effect of the regional vibration isolation module. A design calculation and analysis process for the regional vibration isolation module with high vibration isolation performance is established from the aspects of the general arrangement of the regional vibration isolation module, finite element modeling, modal analysis of the middle raft, module modal analysis, module static analysis and module harmonic response analysis. The design of this type of regional vibration isolation module and the calculation and evaluation of vibration isolation index have been completed, and its vibration isolation performance has been tested. The results show that the vibration isolation performance of this type of regional isolation module can meet the design requirements of the high vibration isolation index of the engine room pump set for the quiet ship.

A set of shipboard helicopter integrated logistic support helicopter integrated logistic support(ILS) methods adapting to extreme environmental conditions, such as polar low temperature and icing, is proposed in order to meet the increasing requirements of ILS for helicopters on polar ships in China. The current common polar rules, standards and ship configuration are studied to identify their incompatibility with extreme polar environments. Targeted improvement plans are then proposed based on relevant domestic and international systems. These improved helicopter ILS methods for polar ships can be selectively applied to the design and construction of new generation polar ships.

The maximum ship bridge impact force and its relationship with influencing factors are of great significance for the reduction of the harm to the personal security and safety of their belongings caused by ship bridge collision. The finite element model of the ship bridge collision has been established by using ANSYS/LS-DYNA to calculate the ship bridge impact force under different impact velocities and impact angles. And the calculated results are compared with those from the rules of various countries. A model for the prediction of the maximum ship bridge impact force is then established under three training parameters of the maximum impact force value, impact angle and impact velocity by using the Back Propagation (BP) neural network technology together with the simulation data. Finally, an empirical formula of the relationship between the maximum impact force and the impact velocity and impact angle is fitted by analyzing the scatter diagram of the impact velocity and the impact angle. And the results of the empirical formula are compared with the finite element simulation results and the neural network prediction results to validate the accuracy of the empirical formula. It provides a rapid method for evaluating whether the ship bridge collision will have catastrophic consequences.

The bearing capacity of typical plate panel have been studied based on the statistical data of large size ships. The influence of the length and width of the plate panel and the boundary stiffener scantlings are separately analyzed based on the load characteristics of the plate panel, in order to summarize the laws affecting the bearing capacity of various plate panel. By creating a look-up table of the influence coefficients for each variable, the relationship between each variable and the bearing capacity of the plate panel has been established for the rapid evaluation of the bearing capacity of the plate panel under the lightweight equipment bracket. This method can simply, efficiently and quickly determine whether the plate panel under the lightweight equipment bracket needs to be further strengthened.

High-speed crafts need to apply regulations that are different from conventional ships due to the characteristics of high speed, light weight and special operations. The International Code of Safety for High-Speed Craft issued at 2000 ( 2000 HSC CODE), as a relatively complete rule applicable to the high-speed craft, is widely accepted by various Maritime Administrations as the design basis for the high-speed craft. The safety principles of the 2000 HSC CODE and the applicability to various Maritime Administrations are briefly introduced. Then the accident types and causes of the high-speed craft are analyzed through domestic and international high-speed craft accidents. And the risk control and design measures applicable to the high-speed craft are further introduced, including general design requirements such as operation restrictions, damage stability, fire protection and evacuation analysis, for understanding the safety principles and guiding the design of the high-speed craft.

The intake duct is one of the main components of a waterjet, and the hydraulic loss in the intake duct is an important part of the total loss of the waterjet. The geometry structure of the intake duct induces non-uniform inflow of the propulsion pump, which has adverse effects on the hydraulic efficiency and dynamic excitation of the waterjet. The intake duct of the waterjet is numerically simulated by using the adjoint method, the flow equations are first solved in the forward direction, then followed by the reverse solution of the adjoint equations. The flow region most related to the inflow is obtained based on the field of the adjoint operator. The method to capture the inflow surface of the waterjet duct based on the adjoint method is then established and verified. The duct geometry is optimized through the adjoint method by taking the boundary of the intake duct as the design input variable and the non-uniformity of the outflow as the objective. After 8 iterations, the non-uniformity of the outflow relatively decreases 18.7%, which validates that the adjoint method can effectively optimize the geometry of the intake duct.

Thruster is the core equipment of ship navigation, and the choice of thruster is the core factor affecting the combat effectiveness of ship. The state-of-the-art of typical thrusters has been outlined based on the development of the equipment and technology of high-performance ships. It focuses on the relationship between the propulsion system and the ship hull with a systematic analysis from two aspects: the influence of requirements of ship multiple operation conditions, high speed and low noise on the development of the propulsion technology, and the improvement of the performance of ships by the development of propulsion technologies such as special propeller propulsion and waterjet propulsion. The effects of using propellers and waterjets on the resistance, maneuverability and noise of the ship are compared based on the full-scale and model test data of a 600 t law enforcement platform and a Swedish Navy Vessel. Combined with the state-of-the-art of high-performance ships in China, the development of the thruster technology is finally prospected to meet the requirements for the overall performance improvement of ships.

Facing the development needs of efficient propulsion systems for new-type ships, the traditional modes have been replaced by the energy conversion mode with a higher energy density by combing the counter-rotating impeller with the waterjet propulsion technology. The steady internal flow field analysis and unsteady impeller interference characteristics are studied for two different propulsion schemes with similar basic parameters and different front and rear impeller energy distribution ratios by using the CFD numerical simulation method. The results show that the propulsion efficiency of the counter-rotating waterjets with two different energy distribution ratios are basically the same, with a wide range of speed and a wide range of high-efficiency. The front impeller plays an adjusting function and reduces the influence of the non-uniformity of the inlet flow field on the rear impeller. The unsteady performance of the counter-rotating waterjet can be improved by increasing the load of the rear rotor and reducing the energy distribution mode of the load of the front impeller, with significant reduction of the impeller exciting force and pressure fluctuation amplitude.

Surf-riding/broaching is one of the five stability failure modes newly included into the Second Generation Intact Stability Criteria by the International Maritime Organization. It is considered to be the most complex one among the five failure modes due to its strong nonlinearity and chaotic characteristics, hence having high academic research value. This paper introduces the researches related to the surf-riding/broaching in recent years, elaborates the research progress of the theoretical prediction, numerical simulation, model test and specifications, as well as the research developments concerning the influence of the surf-riding/broaching on the ship design and ship operation. The key problems that have not been fully solved and the bottleneck technologies that need to be broken are analyzed based on the state-of-the-art of the ship surf-riding/broaching. It can provide references for the key research directions in the future.

The difficulty and cost of the installation of offshore wind turbine (OWT) increases with the rapid development of the scale of the global offshore wind industry, the continuous enlargement of the capacity of the wind turbine and the development of wind farms towards deep sea. The installation methods suitable for large wind turbines (10 MW and above) in deeper waters and harsh sea conditions shall be thoroughly studied and refined to address this situation. Therefore, this article introduces and discusses the main installation methods of OWTs and the characteristics of OWT installation vessels, as well as their future development needs. On this basis, the installation difficulties of current OWTs are summarized. The research progresses in the numerical simulation of the OWT installation are further reviewed. The scheme of combining numerical simulation with the planning and on-site construction stages of wind turbine installation is discussed in detail to ensure safe construction and improve installation efficiency.

The mathematical models of the marine riser lowering blowout preventer (BOP) and the drill string lowering subsea Xmas tree are studied based on new type of cylinder hoisting system, in order to explore the feasibility of accurate operation and the performance of the auxiliary underwater equipment with drilling string compensation function. A simulation model of a cylinder hoisting system under the subsea installation condition is built on the AMESim platform. The subsea installation is simulated when the active drill string compensation is opened and closed under the class 4 sea condition. The maximum safe operation height of a single lifting and lowering operation is analyzed to discuss the impact of different sea conditions on the subsea installation. The results show that the cylinder hoisting system greatly improve the safety of the subsea installation due to its own active compensation function, and the sea condition has a great influence on the operation window and limit operation height. The research results can provide certain theoretical guidance for the national engineering implementation and the field application of the cylinder hoisting system.

An automatic modeling method for solid model of structure is proposed based on the frame model of the lashing bridge structure created by parameterized templates, in order to improve the efficiency of 3D design of lashing bridges in CATIA V6. The geometric features and parameter properties of the components of the structure frame model are analyzed and reviewed. An automatic modeling program is then developed for the lashing bridge by using the professional interfaces that are provided by the secondary development tool component application architecture（CAA） together with the out of the box functions of building solid model of the structure on the CATIA V6 platform. The feasibility and efficiency of the automatic generation technology for the structure detail model（SDM） of CATIA V6 are verified based on the 3D design of the lashing bridge for a 16 000 TEU container ship. This automatic modeling technology improves the 3D design methodology of the lashing bridge based on CATIA V6, resulting in higher modeling efficiency and accuracy than the manual modeling technology with reduced implementation cost of the 3D design, indicating that the technology has strong engineering practical value.

An experimental platform of an unmanned planning craft equipped with multiple sensors and control systems is proposed aiming at the insufficient system verification and evaluation of the path planning and obstacle avoidance control of the unmanned surface vehicle in real environment. The developed experimental platform integrates the LiDAR, depth camera, global positioning system(GPS), ultra wide band (UWB) positioning system, gyroscope and other sensors, and uses main controllers and bottom controllers based on the robot operating system(ROS) and Free_RTOS operating system. The experimental platform consists of the planing craft itself, the sensing system, the bottom controller and the remote monitoring system, including the upper positioning algorithm, the path planning algorithm and the actuator control algorithm. A comprehensive experimental platform including mapping, positioning and remote monitoring is built on the unmanned planning craft equipped with various sensors. The effectiveness of the path planning and obstacle avoidance control algorithm is verified by the navigation experiment of the planning craft. It is supposed to provide theoretical references for the technological development and application of unmanned surface vehicles.