• Bulletin of the Society of Naval Architects of Korea
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• v.32 no.1
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• pp.36-39
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• 1995

본고에서는 고속선의 항행 안전성과 관련된 공통의 문제로서 파랑중 조종성능에 관해서 언급하 고자 한다. 파랑중 조종성능이 문제시되는 것은 선박이 추파(following seas) 또는 추사 파(quartering seas)를 받으면서 고속으로 항해할 때이다. 보통의 속도 범위에서 운항되는 일반 선박중에서도 컨테이너선, 어선 등과 같이 비교적 속력이 빠른 선박은 추사파중에서 선수 동 요가 크게 일어나며, 보침을 위한 조타량이 커짐과 동시에 힁동요가 심하게 일어나는 것으로 알려져 있다. 이러한 불안정 현상은 정도의 차이는 있을지언정 고속선에서도 마찬가지 경향을 보이고 있다. 파랑중 조종성능을 요약하면 추파 또는 추사파중에서의 복원성과 보침성 문제에 귀착된다, 추사파중에서의 복원성 문제는 선체 중심이 파정에 위치할 때 복원력 저하로써 설명될 수 있으며, 이러한 현상은 파장과 선체 길이가 거의 같고 선속이 파속과 거의 같은 조건하에서 일어난다고 알려져 있다. 이러한 조건을 만족하는 선속은 Froude수 0.4 정도로서 고속선의 운항 범위에 미달되는 속도이다. 추사파중에서의 보침성 문제는 브로칭(broaching-to) 현상으로써 설명될 수 있으며, 브로칭 현상은 파장이 선체 길이의 2배 정도이고, 선속과 파속이 거의 같은 조건하에서 일어난다고 알려져 있다. 이러한 조건을 만족하는 선속은 Froude수 0.56 정도로서 고속선의 운항 범위와 일치하는 속도이다. 따라서 본고에서는 고속선을 대상으로 하기 때문에 복원성 문제는 다루지 아니하고 브로칭 현상에 관해서만 간략히 기술하기로 한다.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 2022.06a
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• pp.115-116
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• 2022

자율운항선박 원격제어시스템 구현을 위해서는 통신네트워크의 활용은 필수적이다. 하지만 현재 VSAT, LTE, WIFI를 활용한 통신네트워크의 방해요인중 하나는 시간지연이다. 다양한 연구를 통해 시간지연의 측정과 감소를 위한 연구가 진행중에 있다. 본 연구에서는 이러한 시간지연에 따라 항해사의 제어형태를 파악하기 위한 준비단계로 해양사고 재결서를 통해 분석한 결과를 바탕으로 시나리오를 개발하여 시뮬레이션을 통한 선박조종성능 만족도 평가를 시행하였다. 향후 이를 바탕으로 시간지연에 따라 원격제어자에게 선박조종성능을 저해하는 요인을 식별하고 이를 제거 및 방지하기 위한 방법에 대해 제안하고자 한다.

• Journal of Navigation and Port Research
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• v.40 no.6
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• pp.353-360
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• 2016

The International Maritime Organization (IMO) has issued international standards for ship maneuverability and stability. These have been established to improve marine safety and influence the direction of research. The previous literature has been researched, but there are few studies on the relationship between ship maneuverability and stability. This study carried out a fundamental experiment to quantitatively evaluate that relationship. Radius of turn and maximum heel angle depending on changing were analyzed through a turning test using a free running model ship. The test results show the change tendency of decreasing turn radius and increasng maximum heel angle according to a GM decrease. A rough estimate equation is proposed to predict the change tendency on radius of turn and angle of maximum heel as GM decreases. Many ships can suddenly experience reduced GM due to unexpected reasons during sailing. The results in this study can be used as fundamental data to estimate a ship's tactical turn diameter and variable heel angle for steering as GM decreases.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 2020.11a
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• pp.72-74
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• 2020

일반적으로 선박조종에 필요한 중요한 성능으로 보침성능, 변침성능, 선회성능, 정지성능을 중요하게 여긴다. 이러한 조종성능은 선체의 선형과 함께 타와 엔진으로 표현될 수 있으며 특히 엔진의 성능은 선박의 안전운항과 직결되어 있다. 따라서 선박이 충분한 출력을 확보하지 못하면 항내조선시 선박의 안전을 담보하기 힘들며 또한 황천항해시 외력을 이기고 선박을 안전하게 조선하기 힘들다. 본 연구에서는 2020년 4월 6일 발생한 밀라노브릿지 사고를 통해 선박의 엔진출력을 저해하는 요소인 프로펠러 레이싱, 공전현상, 벤틸레이션 현상에 대하여 고찰하고자 하며 이를 통하여 선박의 조종성능에 미치는 출력을 중요성에 대하여 강조하고자 한다.

• Proceedings of KOSOMES biannual meeting
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• 2003.11a
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• pp.141-148
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• 2003

Yaw-checking and course-keeping ability in IMO's ship manoeuvrability standards is reviewed from the viewpoint cf sole navigation Three kinds of virtual series-ships, which have different course instability, are taken as test models. The numerical simulation on Z-test is carried out in order to examine the correlation between known manoeuvrability in spiral characteristics and various kinds of overshoot angle. Then simulator experiments are executed with series-ships in a curoed, narrow waterway by six operators(five active pilots and one ex-captain) in order to examine the correlation between known manoeuvrability and degree of manoeuvring difficulty. IMO criteria for yaw-checking and course-keeping ability are discussed and revised criteria are proposed.

• Journal of the Korean Society of Marine Environment & Safety
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• v.14 no.2
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• pp.157-162
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• 2008

The ship's maneuverability is the important factor to avoid ship's collisions. The ship's maneuverability is usually measured in a deep water, and the turning ability is decreased and the course stability is improved in a shallow water. The variation of the turning ability could cause the risk of collision. In this paper, we proposes application technique of Variable Safe-Guard Ring to consider the shallow water effect and to be simple to estimate the grade of collision risk simultaneously. Through the mathematical simulation, the availability of new method was varified. Therefore this method is expected enough to support a maneuver for collision avoidance.

• 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 the Society of Naval Architects of Korea
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• v.35 no.1
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• pp.46-53
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• 1998

In this paper, we studied to improve Inoue's[1] and Kijima's[2] model used to predict ship's manoeuvrability at initial design state. To perform this work, we carried out PMM(Planar motion Mechanism) test and rudder open water test for 12 models of low-speed blunt-ship which have horn type rudders and bulbs in afterbody. As we adopted MMG(Mathematical Modelling Group) model, we could analyze hydrodynamic and MMG experimental coefficients. The regression analyses by principle parameters were carried out for hydrodynamic and MMG experimental coefficients. The regression analyses by principle parameters were carried out for hydrodynamic and MMG experimental coefficients and the equations by regression analysis wee used to search sensitivities and to estimate ship's manoeuvrability. We had simulated ship's manoeuvrability to check revised MMG.

• Journal of the Korean Society of Marine Environment & Safety
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• v.19 no.2
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• pp.193-199
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• 2013

Course keeping ability of ships under wave are analyzed with wave. The simulation with three degrees of freedom is developed and 3-D source distribution method is applied to get wave force for the simulation. The simulation is conducted with the restriction of maximum rudder angle and time delay of control and regular wave and irregular wave are considered as the source of external forces. Simulations with ships which have different maneuverability with tuned hydrodynamic coefficients are developed to assess the variation of the course keeping ability depending on the ship's maneuvering characteristics. The course Keeping ability is evaluated by comparison of distance while the ships are simulated with autopilot control.

• 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.