• Title, Summary, Keyword: Towing light

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Evaluation of Resistance Performance of a Racing Boat using Unmanned High-speed Towing Carriage

  • Shin Jeongil;Yang Jiman;Park Rowon;Kim Jaesung;Kim Hyochul
    • Journal of Ship and Ocean Technology
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    • v.9 no.2
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    • pp.1-10
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    • 2005
  • A light-weight cantilever type towing carriage was devised and installed in the towing tank at Seoul National University. Wireless measurement devices were also provided for appropriate data acquisition during high-speed towing tests. With the new carriage system, a series of model tests were performed to investigate the hydrodynamic characteristics of the racing boat in the towing tank and the resistance test results had sufficient accuracy so that they could be used in the development of a high speed planning hull.

A Study on the Resistance Characteristics of a Stepped Planing Hull Using a High-Speed Towing System (고속 예인시스템을 이용한 단을 가진 활주형선의 저항특성 고찰)

  • Shin, Jeong-Il;Yang, Ji-Man;Park, Ho-Won;Kim, Jae-Sung;Kim, Hyo-Chul
    • Journal of the Society of Naval Architects of Korea
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    • v.42 no.4
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    • pp.341-349
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    • 2005
  • With increasing demands of high speed transportation, recently a lot of high speed marine vehicles, such as SWATH, semi-planing craft, planing craft, hydrofoil craft, SES and so on, have been paid attention especially in high speed region over the Froude number 0.5. The resistance characteristics of the vehicles should be experimentally evaluated in the towing tank. At the Seoul National University, a light-weight cantilever type towing carriage was devised and installed in the towing tank. Wireless measurement devices were also provided for appropriate data acquisition during high-speed towing tests. With the new carriage system, a series of model tests were performed to investigate the hydrodynamic characteristics of a stepped planning hull in the towing tank and the resistance performances of the hull are introduced in this report.

A Study on Improving Discrimination of Towing line of Tug-barge for Night sailing (예부선 야간항해 시 예인삭 식별 향상방안에 관한 연구)

  • Kim, Se-Won;Jeong, Woo-Lee
    • Journal of Navigation and Port Research
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    • v.34 no.5
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    • pp.305-309
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    • 2010
  • This paper is provided to improve the discrimination of the towing line for tug-barge at the night sailing. As tugboat industry develops, marine accidents by tugboats are increasing. The main cause of accidents by tugboats is operators' negligence, and that portion is over 70 percent in total marine casualties by tugboats. The biggest cause of negligence is the passing through the towing line at night time. This paper suggests the ways to hinder operators' transit and improve discrimination of towing line(s) at night time.

Design and Fabrication of LED Navigation Lights (LED 항해등의 설계 및 제작)

  • Kim, Il-Kwon;Kim, Dong-Geon;Kil, Gyung-Suk;Cho, Heung-Gi;Cho, Kyu-Lyong
    • Journal of the Korean Institute of Electrical and Electronic Material Engineers
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    • v.25 no.9
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    • pp.743-749
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    • 2012
  • In this paper, we designed and fabricated LED navigation lights which can replace the existing ones immediately and overcome disadvantages due to use of conventional lamps. To decide the best arrangement and position of a LED module, optical systems of existing navigation lights were analyzed and refracted routes of rays were simulated. The electrical and optical characteristics of the fabricated LED navigation lights were measured and analyzed with a goniophotometer. To calculate ranges of visibility, the vertical and horizontal luminous intensity distributions were evaluated in accordance with the COLREGs (convention on the international regulation for preventing collisions at Sea). From the results, the proposed LED navigation lights showed suitable characteristics for marine environment with the power consumption reduced by 90% and the maximum luminous intensity increased by 20% compared to the existing navigation lights.

Modeling of flat otter boards motion in three dimensional space (평판형 전개판의 3차원 운동 모델링)

  • Choe, Moo-Youl;Lee, Chun-Woo;Lee, Gun-Ho
    • Journal of the Korean Society of Fisheries and Ocean Technology
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    • v.43 no.1
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    • pp.49-61
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    • 2007
  • Otter boards in the trawl are the one of essential equipments for the net mouth to be spread to the horizontal direction. Its performance should be considered in the light of the spreading force to the drag and the stability of towing in the water. Up to the present, studies of the otter boards have focused mainly on the drag and lift force, but not on the stability of otter boards movement in 3 dimensional space. In this study, the otter board is regarded as a rigid body, which has six degrees of freedom motion in three dimensional coordinate system. The forces acting on the otter boards are the underwater weight, the resistance of drag and spread forces and the tension on the warps and otter pendants. The equations of forces were derived and substituted into the governing equations of 6 degrees of freedom motion, then the second order of differential equations to the otter boards were established. For the stable numerical integration of this system, Backward Euler one of implicit methods was used. From the results of the numerical calculation, graphic simulation was carried out. The simulations were conducted for 3 types of otter boards having same area with different aspect ratio(${\lambda}=0.5,\;1.0,\;1.5$). The tested gear was mid-water trawl and the towing speed was 4k't. The length of warp was 350m and all conditions were same to each otter board. The results of this study are like this; First, the otter boards of ${\lambda}=1.0$ showed the longest spread distance, and the ${\lambda}=0.5$ showed the shorted spread distance. Second, the otter boards of ${\lambda}=1.0$ and 1.5 showed the upright at the towing speed of 4k't, but the one of ${\lambda}=0.5$ heeled outside. Third, the yawing angles of three otter boards were similar after 100 seconds with the small oscillation. Fourth, it was revealed that the net height and width are affected by the characteristics of otter boards such as the lift coefficient.

A Study on the Development of the Collision Prevention System for Aids to Navigation by Early Identification of the Tug Boat (예인선 조기 식별을 통한 항로표지시설 추돌 방지 시스템 개발 연구)

  • Han, Ju-Seop;Yu, Yong-Su;Park, Tae-Keun;Kim, Hwa-Young
    • Journal of Navigation and Port Research
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    • v.43 no.6
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    • pp.437-443
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    • 2019
  • Aid to navigation is a navigational aid facility that informs a sailing vessel of its location and direction as well as a location of a specific obstacle by means of a light, shape, color, sound, radio wave, etc. It can be valuable in improving the safety of day and night vessel navigation at sea. For the safety of the tug boat, the minimum equipment requirements for each type of tug boat are arranged. Despite these preparations, the collision accidents between tug boats, barges, and light buoys can occur when the tug boat turns due to the length of the tow-line, tidal current, and the barge's momentum etc. The purpose of this study was to propose the basic system that analyzes the physical relationship between two vessels regarding the tug boat-barge-light buoy dynamics and propagate the corresponding data through the aid to navigation management & operation systems in use at each regional oceans and fisheries.

Improving of the Fishing Gear and Development of the Automatic Operation System in the Anchovy Boat Seine- II Analysis of escaping behaviour of anchovy in relation to underwater light and towing flow velocity (기선권현망어업의 어구개량과 자동화조업시스템 개발- II 수중광 및 예망유속과 멸치의 도피반응 행동 분석)

  • 김용해;장충식;안영수;김형석
    • Journal of the Korean Society of Fisheries and Ocean Technology
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    • v.37 no.2
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    • pp.78-84
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    • 2001
  • Escape behaviour of the anchovy (Engralius japonica, total length 4-7cm) at the inside wing net and bag net in the anchovy boat seine was observed by underwater video camera in order to clarify the relationship between visual stimulus of the gear or relative water flow inside gear and reacting behaviour. The vertical attenuation coefficient of underwater illuminance in the offshore of Keoje island and Tongyoung was ranged from 0.24 to 1.03 and it could be affect visual range and visual contrast of the fishing gear. The relative water flow at the joint part between inside wing and bagnet while towing was 1.5 times higher than at the middle part of inside wing or fore part of bag net, but it was estimated under than maximum swimming speed of 4-7 cm anchovy. The mean escaping number of anchovy from end part of inside wing of 30 cm mesh to out side for a minute within visual range of video camera was 455 and anchovy swimming forward from bag net through flapper was 308. These results revealed anchovy could escape as voluntary response in spite of higher visual stimulus or higher water flow.

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