• Journal of Navigation and Port Research
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• v.34 no.8
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• pp.629-634
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• 2010

Mathematical model of maneuvering motion for a Mobile Harbor is established and versatile applications to the special situations of maneuvering are attempted. The Mobile Harbor in this research has twin Azipod thruster and twin bow thruster. In order to predict the maneuverability of Mobile Harbor, a mathematical model was developed on the basis of MMG model, and some model test results were adopted for the simulation of Mobile Harbor. As a result, the turning motions of the Mobile Harbor were successfully calculated. and the optimal berthing system was completed.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 2016.05a
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• pp.71-74
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• 2016

선박이 대형화됨에 따라 안전과 효율 측면에서 항내 선박 조종의 중요성은 점차 커지고 있다. 항내 선박 조종은 저속 또는 극미속 상태에서 이루어지며 항만 혼잡도에 큰 영향을 받는다. 항내 선박 조종시 예선과 선수미 스러스터, 기관과 키를 사용할 때, 항해사와 도선사들이 전심을 모멘트의 레버리지 중심으로 생각하고 있다. 전심은 전통적으로 선박이 전진할 때 선수에서 1/3L, 후진할 때 선미에서 1/4L 부근에 위치한다고 알려져 있으나 조류, 바람, 예선 등 외력의 힘이 작용했을 때 전심의 위치는 변하게 된다. 본 연구에서는 전심의 위치를 다양한 사례를 통하여 조사하여 선박조종에 활용상의 문제점을 밝히고 이 대신에 선체의 수저항 중심을 선박조종상 예선, 키, 쓰러스터 등에 의한 힘들의 중심 사이에 작용하는 우력으로 제안하고 이를 항내 선박 조종에서의 활용할 수 있는 사례를 제시한다.

• Journal of the Society of Naval Architects of Korea
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• v.57 no.1
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• pp.52-59
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• 2020

This study aims to investigate the bow thruster performance of the research vessel "NARA" by full-scale maneuvering trials. The thruster test method refers to ITTC's recommended procedures and guidelines. Turning tests with the bow thruster are performed at speed conditions of 0, 2, and 4 knots. The test results indicate that the Rate of Turn (ROT) increased when the ship is in a higher speed condition. Due to the position of the propeller and the housing of the bow thruster, there is difference in the efficiency of the bow thruster according to the turning direction. Zigzag tests with the bow thruster were conducted at speed conditions of 2 and 4 knots. At speeds above 4 knots, it seems difficult to change the course only with the bow thruster.

• Journal of the Society of Naval Architects of Korea
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• v.57 no.6
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• pp.345-352
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• 2020

This study aims to investigate the crabbing motion of the research vessel "NARA" by full-scale maneuvering trials. The crabbing test method refers to ITTC recommended procedures and guidelines. In order to minimize the fluctuation of the heading angle due to the external force acting on the hull during the pure lateral motion, the tests are conducted using the dynamic positioning system applied to the ship. The test results are analyzed by applying a low-pass filter to remove the noise included in the measurement data. Three conditions are set to define the steady state of crabbing motion. The index to be derived from the crabbing test is quantitatively presented. The ship is confirmed to be capable of the lateral motion of up to 0.844m/s in Beaufort 3.

• Journal of the Korean Society of Marine Environment & Safety
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• v.28 no.1
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• pp.10-18
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• 2022

With the increase in world trade through ships, the destruction of the marine ecosystem and socioeconomic damage due to invasive alien species (IAS) are continuously increasing. In particular, marine organisms attached on the hull surface and niche area increase the friction resistance of ships as well as the invasion of non-indigenous species, and causes a decrease in operational efficiency and an increase in GHG (Green House Gas) emissions. The International Maritime Organization (IMO) has recently begun revising guidelines for the control and management of ship's biofouling, and New Zealand and California in the United States are already regulating biofouling management under their own laws. This study investigated the management status of the submerged surface of ships and marine organisms attachments on five international ships entering South Korea, and analyzed species group and coverage (%) of biofouling communities to evaluate the LoF (Level of Fouling) rank. Macroflouling was observed on all ships surveyed, and specially, the adhesion of macro organisms in niche areas such as bow thruster, bilge keels and sea-chest gratings appeared to be at a serious level. This study proposed the management direction our country should take with regard to ship's biofouling and the improvement measures for evaluation of LoF rank and inspection methods of hull and niche ares.