• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 2017.11a
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• pp.19-21
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• 2017

Ship maneuvering performance is usually estimated in calm water conditions which provide valuable information about the ship maneuvering characteristics at the early design stage. However, the course-keeping ability and the maneuvering performance of a ship can be significantly affected by the presence of waves when ship maneuvers in real sea condition. Therefore, it is necessary to understand the maneuvering behavior of a ship in waves in the viewpoint of ship safety in the design stage. In this study, the force and yaw moment acting on a moving ship in regular waves with different wave length and wave direction will be performed in the square wave tank in Changwon National University. The results of this study can be used to help a person to design a ship hull with the best ship maneuverability in waves and disseminate knowledge on predicting ship maneuvering in regular waves in various wave directions.

• Journal of Advanced Research in Ocean Engineering
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• v.4 no.3
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• pp.105-114
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• 2018

In the past, traditional methods of research on ship maneuvering performance were estimated in calm waters. However, the course-keeping ability and the maneuvering performance of a ship can be influenced by the presence of waves. Therefore, it is necessary to understand the maneuvering behavior of a ship in waves. In this study, the force acting on a moving ship and a rudder behind the model ship will be performed in regular waves in Changwon National University (CWNU). In addition, the prediction force acting on the rudder in calm waters was carried out and compared with those of Computational Fluid Dynamics (CFD). Model test in regular wave was performed to predict the force acting on the ship and the rudder behind the model ship in various wave directions. The effects of wavelength and wave direction on hydrodynamic forces acting on the ship hull versus rudder angle is discussed.

• Journal of Ocean Engineering and Technology
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• v.35 no.3
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• pp.173-182
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• 2021

The maneuvering performance of a ship on the actual sea is very different from that in calm water due to wave-induced motion. Enhancement of a ship's maneuverability in waves at the design stage is an important way to ensure that the ship navigates safely. This paper focuses on the maneuvering prediction of a Russian trawler in wind and irregular waves. First, a unified seakeeping and maneuvering analysis of a Russian trawler is proposed. The hydrodynamic forces acting on the hull in calm water were estimated using empirical formulas based on a database containing information on several fishing vessels. A simulation of the standard maneuvering of the Russian trawler was conducted in calm water, which was checked using the International Maritime Organization (IMO) standards for ship maneuvering. Second, a unified model of seakeeping and maneuvering that considers the effect of wind and waves is proposed. The wave forces were estimated by a three-dimensional (3D) panel program (ANSYS-AQWA) and used as a database when simulating the ship maneuvering in wind and irregular waves. The wind forces and moments acting on the Russian trawler are estimated using empirical formulas based on a database of wind-tunnel test results. Third, standard maneuvering of a Russian trawler was conducted in various directions under wind and irregular wave conditions. Finally, the influence of wind and wave directions on the drifting distance and drifting angle of the ship as it turns in a circle was found. North wind has a dominant influence on the turning trajectory of the trawler.

• Journal of the Society of Naval Architects of Korea
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• v.55 no.2
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• pp.103-115
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• 2018

This paper performs a numerical computation of ship maneuvering performance in waves. For this purpose, modular-type model (MMG (Mathematical Modeling Group) model) is adopted for maneuvering simulation and wave drift force is included in the equation of maneuvering motion. In order to compute wave drift force, two different seakeeping programs are used: AdFLOW based on Wave Green function method and SWAN based on Rankine panel method. When wave drift force is calculated using SWAN program, not only ship forward speed but also ship lateral speed are considered. By doing this, effects of lateral speed on wave drift force and maneuvering performance in waves are confirmed. The developed method is validated by comparing turning test results in regular waves with existing experimental data. Sensitivities of wave drift force on maneuvering performance are, also, checked.

• Journal of the Society of Naval Architects of Korea
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• v.48 no.6
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• pp.516-527
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• 2011

This paper considers a numerical analysis of ship maneuvering performance in the high amplitude incident waves by adopting linear and nonlinear ship motion analysis. A time-domain ship motion program is developed to solve the wave-body interaction problem with the ship slip speed and rotation, and it is coupled with a modular type 4-DOF maneuvering problem. Nonlinear Froude-Krylov and restoring forces are included to consider weakly nonlinear ship motion. The developed method is applied to observe the nonlinear ship motion and planar trajectories in maneuvering test in the presence of incident waves. The comparisons are made for S-175 containership with existing experimental data. The nonlinear computation results show a fair agreement of overall tendency in maneuvering performance. In addition, maneuvering performances with respect to wave slope is predicted and reasonable results are observed.

• Journal of the Korean Society of Marine Environment & Safety
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• v.21 no.2
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• pp.215-222
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• 2015

To improve the ocean waves of the ship maneuvering simulator, we study and summarize the visualization elements of the ocean waves and the overall direction of their implementation in detail. We categorize the visualization elements of the ocean waves into five groups, including wave surface, wave breaking, interaction, lighting effects, and underwater. We also analyze the design and implementation issues of the visualization of the ocean waves for ship maneuvering simulator with respect to realistic and real-time ocean visualization, ship dynamics, and application purposes. Through the analysis, we have found that the realistic visualization of ocean waves plays an important role in the generation of immersiveness, more accurate ship motion, and the various and controllable simulation scenarios for the ship maneuvering simulator. Additionally, we have confirmed that there are many visualization elements, methods, and limitations to be considered for the visualization of the ocean waves for ship maneuvering simulator, and we have concluded that the systematic design is required before implementation.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 2018.11a
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• pp.4-6
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• 2018

Traditional methods of research on ship maneuvering performance were estimated in calm water. Ship maneuverability in waves is of vital importance for navigation safety of a ship (ITTC, 2008). The accurate estimation of force and moment acting on the ship and rudder behind propeller are necessary because the rudder, propeller and hull interaction is of key importance. In addition, course-keeping ability and maneuvering performance of a ship can be significantly affected by the presence of wave. In this study, the model test is performed in the regular wave in the square wave tank in Changwon National University and the hydrodynamic force acting on the ship hull and rudder behind the propeller in various wave directions is investigated. The effect of wavelength and wave direction on hydrodynamic force acting on ship and rudder behind propeller in regular waves is discussed.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• v.1
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• pp.285-290
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• 2006

This paper presents an adaptive neural network based controller and its application to Dynamic Positioning (DP) control system of ship. The proposed neural network based controller is developed for station-keeping and low-speed maneuvering control of ship. At first, the DP system configuration is described. And then, to validate the proposed DP system, computer simulations of station-keeping and low-speed maneuvering performance of a multi-purpose supply ship are presented under the influence of measurement noise, external disturbances such as sea current, wave, and wind. The simulations have shown the feasibility of the DP system in various maneuvering situations.

• Journal of Korean Port Research
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• v.5 no.2
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• pp.39-63
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• 1991

A PC-based ship maneuvering simulator was developed which was configured in a high performance IBM PC compatible i486 and i286 computer with a TMS 340 graphic signal processor and 10 MBPS Ethernet Cards. A real-time ship maneuvering simulation program was developed which includes computer generated imagery (CGI) for bird's eye view type and perspective view type. The simulator H/W was designed and manufactured and S/W for interface of various navigation equipments was made Especially, programs for output, analysis, and assessment of simulations results were developed. Communications between PC's are made by using Ethernet bus type LAN system. Simulations could be performed under various environments (current, wind, wave etc.) using data base of harbors and ships. This system can be used for various purposes such as crew's training, harbor and waterway design, and assessment of ship maneuverability in harbor.

• Proceedings of the Korea Committee for Ocean Resources and Engineering Conference
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• 2003.10a
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• pp.232-236
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• 2003

The anchor is laid on seabed and the main engine is worked to against incident environmental loads in typoon. As the main engine is broken down in the storm, the anchor chain is cutted and the vessel is drifted. Although a ship is moored by two point mooring lines to keep the her position, a ship is crashed into a rock because of typoon and the accident of oil spilling may be occured. In this paper, we studied the position-keeping of a ship which is analyized based on the slow motion maneuvering equations considering wave, current and wind. The direct integration method is employed to estimate wave loads. The current forces are calculated by using mathematical of MMG. The two point mooring forces are quasisatatically evaluated by using the catenary equation. The coefficeints of wind forces are modeled from Isherwood’s emperical data and the variation of wind speed is estimated by wind spectrum. The nonlinear motions of a two point moored ship are simulated considering wave, current, wind load in time domain.