• Title/Summary/Keyword: small vessels

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Motion Response Characteristics of Small Fishing Vessels of Different Sizes among Regular Waves

  • DongHyup Youn;LeeChan Choi;JungHwi Kim
    • Journal of Ocean Engineering and Technology
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    • v.37 no.1
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    • pp.1-7
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    • 2023
  • The motion of small fishing vessels is significantly affected by small waves, leading to accidents, such as capsizing or sinking. This paper presents the results of two types of basin tests. The first test analyzed the characteristics of roll and pitch motions among regular waves with the same wave steepness using the drifting state of three (3G/T, 7G/T, 10G/T) small fishing vessels. The second test analyzed the motion characteristics of the 7G/T fishing vessel under different wave steepness. The first test showed that heave and roll motions are significant in the beam sea, while pitch motion is significant in the bow and stern seas. The second test shows that wave steepness has a linear relationship with roll and pitch motions in the bow and stern seas.

The Safety Equipment for Small-Size Vessel (소형 선박용 안전장치)

  • Park, Chun-Kwan
    • The Journal of the Institute of Internet, Broadcasting and Communication
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    • v.17 no.2
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    • pp.69-74
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    • 2017
  • These days as there are a growing vessel volume in the costal area, the marine accidents has being increased. IMO recommend that all vessels have to be equipped with the safety equipments mandatorily for the safety navigation. Almost medium and large size vessels are equipped with the safety navigational equipments, But many small size vessels are not equipped with those ones because of its owner's financial hardship or indifference. So for the safety of small size vessels in the coastal area, the marine accidents such as stranding, sinking, collision, and so on, have to be protected in advance or the occurred accidents has to be treated quickly. In this paper, the safety equipment for small size vessels having these functions has been developed. This equipment can guarantee the safety of small size vessels in defenseless state considerably by displaying these states in seamen's Smart phone or the cheap dedicated terminal and also informing the control center and nearby other vessels of these states.

A Study for Stability Criteria of Small Fishing Vessel (소형어선 복원성 판정 기준에 관한 연구)

  • 박제웅;김주남;허진호
    • Journal of the Korean Society of Marine Environment & Safety
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    • v.5 no.2
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    • pp.45-55
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    • 1999
  • The majority of fishing vessels(under 20 tonnages) in Korea have a high casualty accident of the flood and capsizing occurred by lack of stability. Actually, it is so difficult to make out the data of inclining and stability tests of small fishing vessels after building, because most of them were built on experiences of manufacturer. According to above reasons, the aim of this study is an attempt to propose a stability criteria of small fishing vessels as follows: Firstly, it is examined that the stability is driven from a transverse metacenter height of actual ships, which is able to obtain a basic drawing and stability data. Secondly, it is examined the heeling at high-speed turning, and the period of rolling according to B/D(breadth/depth). Finally, it is suggested the stability criteria by using a dynamic state which is applied in passenger boat and fishing vessels over 24 meters.

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A Study on the Lights and Shapes for the Small Fishing Vessel and the Vessels Towing and Being Towed (소형어선 및 예인선단의 등화 및 형상물에 관한 고찰)

  • Chong, Dae-Yul
    • Journal of the Korean Society of Marine Environment & Safety
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    • v.21 no.4
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    • pp.421-427
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    • 2015
  • This study aims at reviewing first the cases of marine accidents of small fishing vessels and vessels towing and being towed and, the problems concerning such lights and shapes that could be misunderstood for those in concerned Rules, or that could impair their distinctive characteristics or obstruct to keep a proper look-out. And then I wish to make a suggestion of the necessity of amending the National Laws which stipulate the rules for the ship's lights and shapes as follows; Firstly, by amending the "Standard of Construction and Equipment for the Less Than 10 Gross Tonnage of Small Fishing Vessels" small fishing vessel must be equipped with the lights and shapes that are the same as those of "vessel engaged in fishing" prescribed by Rule 26 of the "COLREG 1972" and Rule 84 of the "Maritime Safety Law Act". Secondly, "Standard of Fishing Vessels Equipment" which stipulate the rules concerning the exception of the running lights and radar reflector for the small fishing vessels must be amended to meet the requirement of Rule 20 of the "Maritime Safety Act". Thirdly, the definition of "Length of the tow" which prescribed by Rule 2 of the "Maritime Safety Act" must be amended to meet the Rule 24 of the "COLREG 1972". And also I wish to adhere to the importance of displaying the adequate vessel lights and shapes by every mariner for preventing marine accidents.

Evaluation of Maneuverability of Small Fishing Vessels Based on CFD Simulation under Standard Loading Condition (CFD 시뮬레이션 기반 소형 어선의 표준재화상태에 따른 조종성능 평가)

  • Sun woo Lee;Sang hyun Kim;Hye woo Kim;Hyung seok Yoon;Chang woo Song;Joo hyung Oh
    • Journal of the Korean Society of Marine Environment & Safety
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    • v.30 no.4
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    • pp.348-357
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    • 2024
  • Maneuvering performance is crucial for fishing vessels, especially under operational conditions that involve frequent course changes and weight variations due to catch. Small vessel accidents account for approximately 60% of maritime incidents as of 2022, mainly attributed to collisions and stranding accidents due to insufficient maneuvering performance. Especially, accidents that occur on small vessels less than 10 tons account for about 65% of all accidents. The absence of international standards presents challenges in accurately evaluating the maneuvering performance of small vessels. In this study, a 4.99-ton small fishing vessel was selected as the target, and a 3d-cad model was created. The commercial numerical analysis program STAR-CCM+ was employed to establish a simulation environment for the vessel's maneuvring motion. Based on this standard loading conditions and weight distribution were considered, 10° / 10°, 20° / 20° zigzag tests and 35° turning test were conducted. The results revealed a tendency for decreased yaw and course-keeping performance and improved turning performance as the hull weight increased. However, in partial arrival and full load departure condition, the manoeuvering performance were relatively poor. Based on this, the need for evaluation of maneuvering and standardized criteria of maneuvering performance for safe navigation of small vessels is presented. Furthermore, it is expected that the evaluation results of maneuvering performance in this study can serve as fundamental data for establishing criteria for evaluating the maneuvering performance of small vessels.

Characteristics of Hypoxic Pulmonary Vasoconstriction of the Rat: Study by the Vessel Size and Location in the Lung

  • Lee, Sang-Jin;Kim, Ki-Whan
    • The Korean Journal of Physiology and Pharmacology
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    • v.3 no.3
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    • pp.321-328
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    • 1999
  • Pulmonary blood vessels with diameters of $200{\sim}400\;{\mu}m$ produce considerably more force in response to vasoconstrictor drugs than those which are either smaller or larger. We have therefore investigated whether or not hypoxic pulmonary vasoconstriction (HPV) is more powerful in vessels of these diameters. We have also looked at the possibility that vessels from different regions of the lung respond differently. To do this we have grouped vessels according to their location within the lung as well as by size. We used a small vessel myograph (Cambustion AM10, Cambridge, UK) to study 208 preconstricted $(1\;{\mu}M\;PGF_{2{\alpha}})$ small pulmonary arteries $(300{\sim}800\;{\mu}m$ diameter when stretched to a tension equivalent to 25 mmHg transmural pressure) from 39 rats anaesthetized with 2% inspired halothane. A biphasic contraction was observed in response to hypoxia (ca. 25 mmHg $Po_2).$ The magnitudes of both the first, transient, phase (PT, peak tension) and of the second, sustained, phase (SST, steady state tension) were measured. The latter was measured 40 min after the start of hypoxia. The first phase was most pronounced in vessels with an average diameter of 423 ${\mu}m$ while the second phase was most pronounced in larger vessels (mean diameter 505 ${\mu}m).$ These maximal responses were all seen in vessels somewhat larger than reported by others. The responses of smaller vessels $(400{\sim}500\;{\mu}m)$ did not depend upon their location within the lung, but those of larger vessels $(600{\sim}700\;{\mu}m)$ showed regional differences. Those from the right lobe and those from the base of the lung gave the largest responses. It was especially noticeable that large vessels (631 ${\mu}m$ diameter) from the base of the right lung gave the biggest responses. Thus HPV seems to occur not in a uniform manner, dependent solely to the size of vessels, but it also depends to some degree on the region of the lung from which vessels have been taken. Furthermore, our results suggest that larger vessels, as well as smaller ones, may contribute significantly to HPV.

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Development of Hull form Decision Program Considering Resistance and Stability of Small Fishing Vessels Under 24m (24m미만 소형어선의 저항.복원성을 고려한 선형결정 프로그램 개발)

  • 박제웅;허진호
    • Journal of the Korean Society of Marine Environment & Safety
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    • v.6 no.2
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    • pp.33-46
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    • 2000
  • As far as fishing vessels are concerned, there are two aspects to be noted: One is the stability which is the greatest concern for the safety of fishing vessels, as the corresponding number of casualty is overwhelming compared with those of other types of vessels. To flake it worse, the feature of casualty is rather catastrophic, accompanying major fatalities. The other aspect is related to the needs of improvement of resistance performance along with the hull form development. In particular, small fishing vessels, such as under 24m in length, which is dominant size in the type, need further scrutiny to enhance the qualities mentioned above, as relevant standards/criteria on the issues are not shown clearly and, therefore, implemented for the design or assessment.

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Performance of Magnetic Compasses Installed on the Small Fishing Vessels (연안어선 자기컴퍼스에 관한 연구)

  • Hong, Jang-Pyo;Shin, Hyeong-Il
    • Journal of the Korean Society of Fisheries and Ocean Technology
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    • v.29 no.1
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    • pp.21-29
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    • 1993
  • The magnetic compass as a principal navigational instrument has been long used to fix ship's position and to determine ship's course. Particularly, in the small fishing vessels the studies on performance and rational usages for magnetic compass are requried to improve the safety and productivity of the small fishing vessels even though gyro compass is developed nowadays. For this purpose, the author examined the present condition of the magnetic compasses which are intalled on 219 small fishing vessels, and carried out a series of performance survey for each compass of them and also found the measured values of deviation by installation position of compass, respectively. The results obtained are summarized as follows: 1. The small fishing vessels less than 4 tons among the 219 small fishing vessels from 1 to 10 tons investigated were 50% of them. Only 1% of them were equipped with the deviation correctors, and 14 fishing vessels used the magnetic compasses which are more than 20 years old. 2. According to the compass installation position, the measured values of the deviation of the compass installed on the top bridge and the compass bed in bridge were ascertained to be the smallest, and those values of the compass installed on the bridge deck above engine room were larger and irregular. 3. The concomitant angle of the magnetic compasses installed on the experimented 4 fishing vessels were measured to be 6$^{\circ}$ to 16$^{\circ}$ and not accorded with the Korean standard values.

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Approaching Method for Detecting Vessels in the Korean Waters using the Panchromatic Imagery of IRS-1C Satellite (Panchromatic 위성 자료를 이용한 선박 확인의 접근 기법)

  • Suh, Young-Sang;Choi, Chul-Uong;Lee, Na-Kyung;Kim, Bok-Kee;Jang, Lee-Hyun
    • Journal of the Korean Association of Geographic Information Studies
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    • v.5 no.4
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    • pp.86-92
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    • 2002
  • The feasibility of counting number of small vessels and position in Korean waters using the panchromatic imageries derived from the IRS-1C was tested. The parameters for interpretation of satellite's imageries of small vessels were location(position), size, shape, shadow, tone, texture and pattern, height and depth, situation and association with other vessels. The position of small vessels in the sea without GCP(ground control point) was considered to be inclusive in the satellite imagery with 35 km semi-diameter, denoting rough geographical position of the vessel. The size of vessel was measured by length from stem to stern of the vessel, distinguished by following wave on the surface water. Offshore fishing vessels were separated from merchant ships by their length smaller than 100 m. The shape of vessels on panchromatic imagery of IRS-1C appeared just streamline. In case of clouds which were similar to the shape of small vessels, we were able to distinguish between vessel and cloud by shadow of cloud in the water surface. The tone of sea surface was dark black while small vessel appeared bright white. Small vessel was distinguished from the rough texture of the sea surface and the regular pattern of the waves with white capes when weather was not so good. The situation of the fishing activity was estimated by information of fishing method related to the fishing boat such as the pair trawl in the Yellow Sea.

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