• KSCE Journal of Civil and Environmental Engineering Research
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• v.33 no.2
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• pp.595-608
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• 2013

This paper is proposed the computation method of moored ship motion considering harbor resonance, and estimated that the harbor resonance have an effect on moored ship motion. The computation of harbor resonance was used CGWAVE model and the computation of moored sip motion was used the Green function method expressed by three dimensions. This method was verified with the field observation data of moored ship motion, and the application of actual harbor was investigated with wave field data and down time record data in Pohang New Harbor. The resonance periods in Pohang New Harbor that obtained from wave field data were 80, 33, 23, 8 minute, which are the long waves, and 42, 54, 60 second, which are the infra-gravity waves inside harbor slip. The simulated results of harbor resonance were corresponded with the wave field data. This study was investigated on 5,000 ton, 10,000 ton and 30,000 ton ship sized in Pier 8 of Pohang New Harbor that the harbor resonance has effect on moored ship motion from simulated results of ship motion in case of included resonance and excluded resonance. In case of included resonance, the ship motion have increased by 12~400 percent when compared with results of excluded resonance. We could find that the harbor resonance have still more an effect on the surge and heave motions of a large size ship and the roll and yaw motions of a small size ship.

• Journal of Navigation and Port Research
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• v.34 no.8
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• pp.623-628
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• 2010

High speed marine vehicle, such as semi-planing, planing craft have been developed recently. These ships paid attention to the resistance characteristics, especially in high speed region. Model test method is divided to two equipment greatly, first 'Towing tank', second 'C.W.C.'. It is difficult to estimate a resistance characteristics for high speed boat. because these are made for low speed ship. This paper suggests a new model test method and system. This is real sea model test and it's comprised of eight part. Firstly, This method is tested at C.W.C that is possible to using in real sea model tes using low speed boat modelt. And then, Real sea model test and CFD calculation are performed and compared with tow way used high speed boat model. It can be a good way to estimate a performance for high speed boat.

• Journal of the Korean Society of Marine Environment & Safety
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• v.29 no.6
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• pp.672-680
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• 2023

Weight is a critical factor in the ship design process given that it has a substantial impact on the hydrodynamic performance of ships. Typically, ships are optimally designed for specific conditions with a fixed draft and displacement. However, in reality, weight and draft can vary within a certain range owing to operational activities, such as fuel consumption, ballast adjustments, and loading conditions . Therefore, we investigated how resistance changes under three different loading conditions, namely overload, design-load, and lightship, for small craft, using both model experiments and numerical simulations. Additionally, we examined the sensitivity of weight changes to resistance to enhance the performance of ships, ultimately reducing power requirements in support of the International Maritime Organization's (IMO) goal of reducing CO2 emissions by 50% by 2050. We found that weight changes have a more significant impact at low Froude Numbers. Operating under overload conditions, which correspond to a 5% increase in draft and an 11.1% increase in displacement, can lead to a relatively substantial increase in total resistance, up to 15.97% and 14.31% in towing tests and CFD simulations, respectively.

• Journal of the Society of Naval Architects of Korea
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• v.36 no.2
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• pp.72-76
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• 1999

To predict the maneuverabiliy of a ship, it is most reliable to carry out the model tests for the ship. But, at the initial design stage of ships, scene other methods of predicting the overall maneuverabiliy of ships with confined data, like principal dimensions and propeller and rudder characteristics, are required. In this paper, the authors suggested new formulas for the linear derivatives of the sway force and yaw moment, based on the captive model test carried out by the Japanese researchers. These formulas can account the effects of stern frame line shape and stern profile, when assessing the maneuverability of ships. The usefulness of the formulas are discussed by comparing the simulations with the model tests.

• Journal of Korean Society of Transportation
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• v.30 no.5
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• pp.91-100
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• 2012

Although Korea's coastal areas increasingly experience marine accident due to frequent ship encounters, increased vessel traffic and large vessel, there is a no specific model to evaluate the navigating vessel's risk for the given situation. The maritime transport environmental assessment is necessary due to the amended marine traffic law. However, marine safety diagnosis is now evaluated by foreign models. In this paper, therefore, we suggest a domestic model catering to and reflecting the characteristics of Korea's costal areas as well as those of vessel navigator's risk. We can evaluate subjective risks using this model, and can establish the model output as maritime risk exposure assessment system. We have performed analyses of variance and multiple comparison to identify the factor affecting subjective risks. As a result, measurable subjective risks of maritime traffic accident based on our suggested model can be expressed using the maritime risk exposure assessment system with geographic information system.

• Journal of the Society of Naval Architects of Korea
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• v.33 no.1
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• pp.65-76
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• 1996

A screw propeller is usually accepted as a propulsor of many kinds of ships. However, for high speed vessels, screw propeller has large cavitation area on the blades so propeller efficiency is decreased and erosion can be happened. To avoid this problem, supercavitating propeller and waterjet are generally used for high speed vessels. In this paper, we introduced the self-propulsion test procedure which has been developed for high speed vessels in Hyundai Maritime Research Institute. The model ship used in experiment represents catamaran about 5.3 m in length. To minimize the experimental errors, two impellers were driven by a single motor. Thrust was calculated by converting the measured pressure to flow rates at the nozzle exit. The test procedure is composed of resistance test, self propulsion test and analysis. In order to measure the pressure, pressure tabs were installed around the nozzle exit and connected to the pressure sensor by vinyl tube.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 2022.11a
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• pp.347-348
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• 2022

자율운항선박 도입에 관한 논의가 국제해사기구에서 본격적으로 시작됨에 따라 자율운항선박 관련 기술개발이 세계적으로 활발하게 진행되고 있다. 그러나, 통신, 보안, 고장진단, 유지보수 등의 기술개발이 아직 미흡하여, 자율운항선박의 상용화까지는 많은 시간이 소요될 것으로 예상된다. 이러한 기술들은 문제가 발생할 경우 선박에 막대한 피해를 발생시킬 수 있으며, 특히, 연안을 항해하는 선박보다는 대양을 항해하는 선박에 더 치명적이기 때문이다. 본 연구에서는 대양항해 시 자율운항선박에 발생할 수 있는 문제들을 극복하기 위한 방안으로 여러 척의 선박을 하나의 그룹으로 묶어 항해하는 그룹항법시스템을 제안한다. 하나의 그룹은 한 척의 유인선박인 리더선박과 여러 척의 무인선박인 추종선박으로 구성되어 있으며, 항해하는 동안 일직선 형태를 유지한다. 리더선박은 출발지에서 목적지까지 미리 설정된 변침점을 따라 항해하며, 추종선박은 리더선박의 경로를 추종하여 항해한다. 선박의 침로를 제어하기 위한 타각 제어기는 선박에서 주로 사용되는 PD 제어기를 구현하여 사용하였다. 그룹항법시스템을 검증하기 위해 선박해양플랜트연구소에서 공개한 KVLCC2의 축소 모형인 L-7 모델을 사용하여 시뮬레이션을 진행하였다.

• Journal of Navigation and Port Research
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• v.47 no.6
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• pp.305-314
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• 2023

In this study, a mathematical model of a 9.77 G/T small fishing vessel was established based on captive model tests. The powering and manoeuvring performances of the vessel in the harbor and coastal sea were focused on, so captive model tests were conducted up to the full-scale speed of 8 knots. Propeller open water, resistance, and self-propulsion tests of a 1/3.5-scaled model ship were performed in a towing tank, and the full-scale powering performance was predicted. Hydrodynamic coefficients in the mathematical model were obtained by rudder open water, horizontal planar motion mechanism tests of the same model ship. In particular, in static drift and pure yaw tests which were conducted at a speed of 2 to 8 knots, the linear hydrodynamic coefficients varied with the ship speed. The effect of the ship speed on the linear coefficients was considered in the mathematical model, and manoeuvring motions, such as turning circles and zig-zags, were simulated with various approach speeds and analyzed.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 2018.11a
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• pp.7-8
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• 2018

파 중 선박 조종운동시험을 위하여 선박해양플랜트연구소 공학수조 내 자유항주시험 시스템을 구성하였다. 모형선 내에 제어계측 장비와 PC를 탑재하고 육상 관제 PC에서 원격 통제, 모니터링하며, 레이저 추적 방식으로 모형선 실시간 위치를 계측하였다. 준비된 시스템으로 KVLCC2 1/100 축소모형선의 규칙파 중 선회시험을 수행하였다. 파 중 선회성능은 초반의 전진거리, 전술직경, 정상선회 시의 궤적밀림 거리, 각도 등으로 지수화할 수 있다. 각 지수를 추출하여 분석하였고, 동일한 파장 조건에 대한 궤적밀림 경향은 유사함을 보였다.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2000.10a
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• pp.388-399
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• 2000

본 논문은 정수계획 문제로 수리모형화 되는 선박운항 일정계획 문제에 대한 컴퓨터 그래픽 기반의 상호 대화식 모델링 시스템의 개발에 관해서 논한다. 선박운항 일정계획 문제는