• 한국항해학회지
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• 제12권1호
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• pp.71-84
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• 1988

For traffic proceeding in random directions on a plane surface the frequency of collision, if no avoiding action in taken ,is approximately proportional to the square of the traffic density and directly proportional to the size and speed of the ship, Avoiding is normally taken and the rte of collisions is therefore also governed by additional factors such as the visibility, the effectiveness of the collisionavoidance rules, the competence of personnel or watchkeeping attitude, the maneuverability of the ship and the efficiency of radar and other equipments. From the viewpoint of watchkeeper who is responsible for maneuvering, watchkeeping attitude such as lookout and action to avoid collision is the most controllable factor among those mentioned above. In practice, according to the investigation of the institution of marine courts, about 50% co collisions occurred is caused by disorbedience to steering and sailing rules of international regulations for preventing collision at sea including lookout. So we classify the process of collisions with first sight of another ship , assessment of risk of collisions and action to avoid collisions and make a factural survey about lookout and action to avoid collisions from the point on "time" and " distance", namely relationship among ship's size, speed, first sight time of another ship, action to avoid collisions ,and distance from sight of another ship to collision occurred. According to the results of the actual survey , we come to conclude that most of collisions occurred are due to improper lookout and ineffective action to avoid collision which means time lag from first sight of another ship to time of action taken to avoid collision is relatively long. is relatively long.

• 한국해양공학회지
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• 제35권3호
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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.

• 한국항해학회지
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• 제24권3호
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• pp.123-132
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• 2000

In order to improve the ship maneuverability, It is important to estimate precisely the hydrodynamic coefficients of added mass forces acting on a ship especially in shallow waters, and simple methods for predicting such hydrodynamic forces Is also very desirable. In the previous paper using 3-Dimension potential flow theory, it has been demonstrated that potential calculation is available to estimate added mass coefficients. The present work is aimed at the suggestion of the simplified formulas for predicting the translation and lateral motion of added mass coefficients in shallow water. So, 3-D potential flow theory is also used to calculate the added mass coefficients in deep and shallow waters for Series 60 model which has 5 different kinds of block coefficients (0.6-0.8), SR196 model and T/S HANNARA. After some series computation, simplified formulas for Predicting the added mass force in shallow waters is suggested based on the computation results of Series 60 model. The formulas consist of the combination of principal dimensions and the water depth; d/B, Cb, d/H. The predicted results are compared with the Computation results for SR196 model and T/S HANNARA. The precision of predicted results by simplified formulas are good enough for the practical use. (d/B : draft-Breadth ratio, d/H draft-Water depth ratio, Cb : Block coefficients).

• 대한조선학회지
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• 제21권4호
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• pp.10-20
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• 1984

When the hydrodynamic coefficients of the ship maneuvering equation are estimated by captive model test, it is difficult to take account of the scale effect between model and full scale ship. This scale effect problem can be overcome by processing the sea trial data with system identification. Extended Kalman filter is used as a system identification technique for the modification of the simulation equation as well as the estimation of hydrodynamic coefficients The phenomena of simultaneous drifting of linear coefficients occur. It is confirmed that two coefficients in each pair-$(Y_v',\;Y_r'-m'u'),\;(N_v',\;N_r')$-are simultaneously drifting and all 4 coefficients are drifting together. Particularly simultaneous drifting and 2 coefficients in each pair is more significant. It is also shown that the simultaneous drifting of 4 coefficients can be reduced by choosing the input data which have the random v'/r' curve and 4 coefficients are estimated within $2{\sim}4%$ error, which may be noise level. So, it is recommended to operate the rudder randomly in sea trial or model test for the application of system identification technique.

• 한국해양공학회지
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• 제38권1호
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• pp.10-17
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• 2024

This study assessed the potential for crabbing motion in waterjet ships by exclusively employing stern thrusters. The theoretical considerations were validated through practical sea trials on the naval vessel PKG (Patrol Killer Guided missile) equipped with three stern thrusters. The control forces were calculated using the force equilibrium equation. The results showed that the hull exhibited rotations and lateral movements under wind influence. The port tail exhibited a leftward turning tendency due to the wind. This phenomenon arises from the dominance of the rotational force generated by the stern thruster over the lateral force exerted by the hull, making it challenging to maintain force equilibrium. In the sea trial, the hull rotated by 10° and moved 10.8 m laterally, with a longitudinal movement of 0.26 m. Remarkably, the lateral movement surpassed the longitudinal displacement, indicating the success of the trial. The substantial lateral travel distance provided tangible evidence that the crabbing motion of the ship is achievable using only stern thrusters. This study contributes valuable insights into enhancing the maneuverability of waterjet ships, offering practical applications for naval operations and maritime activities.

• 수산해양기술연구
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• 제47권4호
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• pp.428-434
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• 2011

To establish a vessel safety management system for improving the safety of vessel's traffic and preventing vessel's traffic accidents, the state of marine traffic in the Busan South Port was investigated and analyzed as preliminary survey of the countermeasures. As a result of the study, there are 1,158 vessels in a day, 48 vessels in an hour, and the maximum traffic is about 118 vessels between 16:00 and 17:00 hours everyday, which requires to establish and operate a traffic control system necessarily for ensuring vessel's traffic safety. Furthermore, passages of tanker, passenger ship, cargo vessel and government vessel showed to sail along main traffic lane to be obtained enough sea depth at the survey area. However, passages of fishing vessel and launch showed to sail freely at all survey area owing to outstanding maneuverability and a shallow draft. Some vessels of launch sailed along main traffic lane, but other vessels crossed to sail it. The passages to cross main traffic lane is higher the risk of collision. Therefore, safety measures are urgently needed for the operation of the Busan South Port management system and the prevention of marine pollution.

• 한국항해항만학회:학술대회논문집
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• 한국항해항만학회 2018년도 추계학술대회
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• pp.12-13
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• 2018

안전운항을 위해 항해사가 숙지하고 있어야하는 것은 선박의 조종성능이다. 선박이 조우하는 상황이나 위험상황에 처했을 때 피항동작을 취하기 위해 변침을 하게 되는데 그러한 조치를 취하기 위해 타각을 얼마큼 줄 건지를 판단하고 직진상태에서 타각을 사용한 이후 정해진 방향으로 바꾸는데 필요한 시간과 어떻게 운동하는지를 예측할 수 있어야 선박의 안전을 확보할 수 있다. 실습선 한바다호의 조종성능을 확인하기 위해 IMO에서 제시하는 $10^{\circ}/10^{\circ}$ 및 $20^{\circ}/20^{\circ}$ 지그재그 테스트와 좌현/우현 선회시험을 시행하였고 실선계측을 통해 이 때 나타나는 선박의 운동을 함께 측정하여 항해사들이 적절한 피항동작을 취할 수 있도록 실습선 한바다호의 조종성능과 선박운동의 정보를 제공하고자 한다.

• 한국정보전자통신기술학회논문지
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• 제17권3호
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• pp.130-140
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• 2024

본 논문에서는 해상상태 환경에 따른 카메라 센서 인식의 오차를 제어하고 보정 하기 위해 칼만 필터를 적용한 방법을 제시한다. 먼저, 함정의 제원을 기술하여 롤링에 따른 오차 정도를 측정하였다. 모델로 선택한 함정인 PKMR-211을 통해 시뮬레이션에 필요한 수면으로부터 현등까지 거리를 제시한 후, 피드백 제어 시스템에서 카메라 오차값을 변수로 삼아 오차 보정을 수행하였다. 실험에서는 함정의 롤링 정도를 각도로 나타내는 변수인 𝛼, 𝛽로 표기하고, 거리에 따른 각도 변화를 비교하였다. 해상 상태 3의 상황에서 칼만 필터를 적용하기 전과 후의 오차를 비교했을 때, 거리와 무관하게 적색등에서는 +1.5556°에서 -1.1544°까지 줄어들었고, 녹색등에서도 동일한 결과를 확인하였다. 이를 통해, 해상 환경에 따른 함정의 움직임을 고려하여 계산을 수행하고, 오차 보정 이후 함정의 향후 기동 안정성을 제시하였다.

• 해양환경안전학회지
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• 제23권6호
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• pp.652-660
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• 2017

최근 총톤수 16만 톤급 이상의 대형 크루즈선이 국내 항에 정기입항하고 있다. 크루즈를 이용한 국내 관광객이 증가함에 따라 정부에서는 크루즈산업 활성화를 위해 항만기반시설 확충에 많은 노력을 하고 있다. 현재 국내 주요 항구에서 크루즈전용부두 공사가 진행되고 있다. 그러나 국내 항만 및 어항설계기준에는 크루즈선 및 접안시설에 대한 표준제원이 제시되어있지 않다. 대상선박의 표준제원이 제시되어있지 않아 전용시설물 설계 및 인허가에 많은 어려움이 예상된다. 그래서 본 연구에서는 크루즈선에 대한 표준제원을 제시하기 위하여 현재 운항중인 크루즈선의 톤수별 대표선형의 제원을 분석하고 PIANC 사례 및 국내 항설기준을 비교분석 하였다. 분석결과 크루즈선은 연안여객선과 선박제원 및 선박조종성능에 차이가 있음을 알 수 있었다. 따라서 크루즈 전용시설물 설계를 위해서는 반드시 대상선박의 제원이 국내항설기준에 반드시 포함되어야 한다. 그리고 선박의 범위를 산정하기 위하여 크루즈선 평균제원 값에 커버율(75%)을 적용하여 크루즈선 표준제원과 수역시설물에 대한 기준을 제시하였다.

• 한국항해학회지
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• 제20권2호
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• pp.1-13
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• 1996

Most of the ShipHandling Simulators of full-mission-bridge system need vast area to install and even PC-based maneuvering simulators are often equipped with Steering Wheel or Engine Telegraphe etc. of data input interface, which necessarily makes the user face with excessive financial burden. These have been one of the obstacles for the officers, captains, pilots and students in access to maneuvering simulation whenever they want to try it in advance prior to actual ship maneuvering. Subsequently, all the officers and captains come to have little chances to train themselves until they arualified as a pilot after a long period of time of realship maneuvering practice on board, which means they have to control they have to control their own ship at sea without clear understanding on her maneuverability when they are forced to do it on the way. And these lack of capability for maneuvering have used so often to result in marine casualties of collision with other ships or pier facilities while maneuvering in harbor. To prevent those accidents by means of enhancing their maneuvering ability, PC-based DeskTop Simulator that allows anyong to access readily at anytime is needed and in conformation to such demand this simulator has been developed. The Software this simulator written in Turbo Pascal Ver. 5.0 has adopted MMG mathmatical model theoretically in part and also it was designed to make it possible that all numeric data inputs and outputs with graphic presentation for maneuvering operation be carried out just only with keyboard and monitor console. With the Simulation software, all the officers, captains, pilots and even students who has a proper computer at hand are expected to be able to make an attempt to simulate the maneuvering of their ownship or any other types of them at any port in which they want to do it.