• 대한조선학회논문집
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• 제61권3호
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• pp.161-169
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• 2024

In order to investigate cavitation performance for the azimuth thruster in Large Cavitation Tunnel (LCT), the cavitation test apparatus was designed and manufactured. Generally the model scale is determined by the pod dynamometer with about 70mm diameter. Recently as ships with azimuth thruster have become bigger, the problem of the model ship installation was occurred. The model ship with pod dynamometer couldn't be installed in the LCT test section. The cavitation test apparatus and technique which can conduct the cavitation test without pod dynamometer were developed. The cavitation tests were conducted in torque identity method instead of thrust identity method. The target ship with azimuth thruster is 18K LNG bunkering vessel. As the full-scale ship test was conducted, the model cavitation tests were conducted at the same operating conditions. The fluctuating pressure levels of the full-scale ship were compared to those of the model tests. Another model cavitation test was conducted in the foreign institute and the cavitation observation results were compared to those of LCT. Through the comparison with the existing results, it is thought that the cavitation test for the azimuth thruster can be conducted in torque identity method.

• 한국항해항만학회:학술대회논문집
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• 한국항해항만학회 2006년도 Asia Navigation Conference
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• pp.49-55
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• 2006

Kinematic GPS provides quite good accuracy of position in cm level. Though K-GPS assures high precision measurement in cm level on the basis of an appreciable distance between a station and an observational point, but it has measurable distance restriction within 20 km from a reference station on land. So it is necessary to make out a simple and low-cost method to obtain accurate positioning information without distance restriction. In this paper, the velocity integration method to get the precise velocity information of ship is explained. Next two experimental results (Zig-zag maneuvering test and Williamson turn) as the ship's maneuvering test and also the experimental results of leaving and entering port as slow speed ship's movement were shown. In these experimental results, ship's course, speed and position are compared with those obtained by kinematic-GPS, velocity integration method and dead reckoning position using Gyro-compass and Doppler-log.

• 대한조선학회논문집
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• 제50권6호
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• pp.429-435
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• 2013

Recently, to improve the safety and maneuverability at fairway around harbor the POD system has been equipped on a ship. And the interest about maneuvering characteristics of a cruise ship has been increasing. In this paper the mathematical model of maneuvering motion of a cruise ship with twin POD system in general speed and slow speed are presented. And the maneuvering coefficients of mathematical model are obtained from the captive model tests using CPMC(Computerized Planar Motion Carriage). Computer simulation using mathematical model in general speed and slow speed are carried out and compared with the results of free running model test with the same model ship. The differences between the mathematical models are compared and discussed. In this paper the mathematical models, the results of captive model test and simulation results are presented.

• 한국시뮬레이션학회논문지
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• 제19권3호
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• pp.17-25
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• 2010

선박 조종 시뮬레이션을 구성하는 기동 모델은 대상 선박의 동역학적인 특성을 현실에 가깝게 구현해야 하며, 신속한 계산 및 결과 처리가 가능하여야 한다. 다중 선박을 대상으로 하는 실시간 조종 시뮬레이션에서는 계산 시간 단축을 위해 일반적으로 선회각이나 선회율, 또는 전진 속도에 대한 1차 미분방정식 모델을 사용하여 선박의 움직임을 구현하게 된다. 본 논문에서는 대상 선박의 선회 시험 정보가 주어져 있을 경우 이를 이용한 선박의 단순 기동 모델링 및 계수 추정법을 제안하였다. 전진속도가 일정한 모델과 전진 속도의 변화를 고려한 모델의 계수 추정법을 수학적으로 전개하였으며, 실선 선회 시험 자료를 이용하여 제안된 모델의 유용성을 검증하였다.

• 한국항해항만학회지
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• 제44권5호
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• pp.363-374
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• 2020

In the past, various research on the effects of waves generated by ships has been investigated. The most noticeable effect of the waves generated by a passing ship is the increase of the hydrodynamic forces and the unwanted large motion of the moored ship and high mooring forces that occur. Thus, it is crucial to investigate the effect of the waves generated by the passing ship near port on the motion of the moored ship and the tension of the mooring lines. A model test was performed with virtual ship-generated waves in a square tank at CWNU (Changwon National University). The IMU (Inertial Measurement Unit) and Optical-based system were used to measure the 6DOF (Six Degrees of Freedom) motion of the moored floater. Additionally the tension of mooring lines were measured by the tension gauges. The effects of the wave direction and wave height generated by the virtual ship-generated waves on the motion of the moored floater were analyzed.

• 수산해양기술연구
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• 제60권2호
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• pp.179-185
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• 2024

The model ship of this study, the Baek-Kyung fisheries training ship of Pukyong National University, has a length between perpendiculars of 85 meters, making it not subject to the IMO maneuverability standards. However, understanding the maneuvering characteristics of the vessel is essential for safe navigation. In this regard, this study was conducted to analyze the results from the sea trials of the model ship conducted in accordance with the IMO maneuverability standards. The results of the turning tests met the standards well while in the zig-zag tests, the first overshoot angle exceeded the standard in the 10°/10° test; however, such results met with a difference of 1.8° in the 20°/20° test. Additionally, using the course-stability discrimination formula, the calculated value was -0.0051, indicating unstable course-stability. The results of the stopping tests met the standards well. It is hoped that the analyzed maneuvering characteristics of the model ship from the study results will contribute to the safety of ship navigation.

• 한국항해항만학회:학술대회논문집
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• 한국항해항만학회 2017년도 추계학술대회
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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.

• 한국해양공학회지
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• 제23권3호
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• pp.53-58
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• 2009

A scale model test for ship Infra-Red signature measurements at sea is impossible, because it is sensitive to the environment. Since we can't control the meteorological environment of the real sea, it can't be carried out with the desired maritime environments. Therefore, in the sea, we made measurements of the weather, operating conditions of the ship, and ship IR signatures under given conditions, and then analyzed them. Conversely, we compared the results of the test with a prediction for a given scenario condition. This paper describes the test items, procedures, and measuring instruments of the experiments at sea and the results from basic researches for methods of estimation and analysis of the measured data.

• 대한조선학회논문집
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• 제45권3호
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• pp.247-257
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• 2008

In this paper, a free running system, which is developed recently for a 2m-class ship models, will be introduced. For the remote control of hardware, GUI of software packages was developed using Visual Basic 6.0, and Host PC with Positioning Board manages Servo drive. Then the drive operates propeller and rudder. Its control performance will be shown. Also its adaptability to the resistance, manoeuverability and seakeeping model tests will be considered through the installation on a KTTC standard ship model from MOERI.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2004년도 추계학술대회논문집
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• pp.727-730
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• 2004

Reduction of a ship's rolling is the most important performance requirement for improving the safety of the crew on board and preventing damage to cargos as well as improving the comfort of the ride. A mass driving anti-rolling system (MD-ARS) might be one candidate of several systems against the ship's rolling. In this paper, three types of MD-ARS, two passive and one active devices, are developed for small ships. After they are installed on the cabin of the small leisure boat, respectively, a series of test is conducted before and after operating them. Through the test, it is confirmed that the roll responses of the ship are pretty well reduced by the system.