• Title, Summary, Keyword: Holding Power

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The Holding Power of the Oil Boom Anchor (오일 펜스 Anchor의 파주력)

  • CHANG Duk Jong
    • Korean Journal of Fisheries and Aquatic Sciences
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    • v.36 no.6
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    • pp.743-748
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    • 2003
  • An oil boom was set up in order to contain diffused oil from spills and for the retrenchment of damage caused by oil Pollution. Therefore, the oil boom anchor needed proper holding power to endure high resistance from flowing streams and to secure the oil boom around the spill, and must dredge directly into the seabed when it is dropped and block oil outflow immediately. This study investigated the holding power of the danforth anchor and the coastal fishing vessel anchor used for oil booms in the KMPRC (Korea Marine Pollution Response Corporation). For each type, a 30 kg and 20 kg anchor were used. The holding power of the danforth anchors were measured by dropping both weights 10 times. However the coastal fishing vessel anchors were dropped only 5 times each, because no substantial differences were found between drops. In the results of the danforth anchors, an anchor awoke occurred in 2 drops of the 30 kg anchor and in 4 drops of the 20 kg anchor, wherein there was no holding power to be measured. With exception to the anchor awoke cases, the maximum holding power of the danforth 30 kg and 20 kg anchors was 250-520 kg and 123-233 kg, respectively. In the case of the coastal fishing vessel anchors of 30 kg and 20 kg, throughout the experiment, there was no occurrence of an anchor awoke. For the 30 kg and 20 kg anchors, the maximum holding power was measured to be 209-230 kg and 155-170 kg, respectively. Therefore, the holding power of the coastal fishing vessel anchor was shown to be much poorer than that of the danforth anchor. However, the holding power of the danforth anchor was very unstable. Due to the occurrences of anchor awoke, there was no holding power and the measurement value of maximum holding power showed too much variation among the drop tests. Also, after the maximum holding power was achieved, anchor awoke occurred easily. In the case of the coastal fishing vessel anchor was much more stabile, because there was no anchor awoke and no instance where holding power failed. Also the maximum holding power was reached quickly and almost no variation occurred among the drop tests.

Model Experiments for the Coefficients of Holding Power of the Hall`s Type Anchor and a Chain Cable (Hall 형 묘 및 묘쇄의 파주력 계수에 관한 모형실험)

  • Kim, Se-Won;Kim, Ki-Yun
    • Journal of the Korean Society of Fisheries and Ocean Technology
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    • v.27 no.2
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    • pp.97-104
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    • 1991
  • Generally, the coefficients of common holding power of an anchor and a chain cable have been reported too higher in their values in the safety of the shiphandling. The model experiment was carried out to find the most suitable coefficients of holding power of the Hall's type anchor and the chain cable in various kinds of seabed. The results obtained are summarized as follows; 1) The coefficients of holding power of the anchor and the chain cable were 4.05, 0.75 in the mud, 3.95, 0.66 in the sand and 3.61, 0.72 in the pebbles respectively. 2) The experimental coefficients of holding power of the anchor and the chain cable were 0.4~0.6 times the values of the coefficients of common holding power. They were almost same as the values of the coefficients of safe holding power in the mud and the sand, but in case of the pebbles, they were 1.4~1.8 times the values of the coefficients of safe holding power. 3) It is considered useful for the safety of the shiphandling to draw curves of the holding power with maximum limits holding power at the various wind forces and the coefficients of holding power.

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A Study on Theoretical Consideration to the Holding Power and Holding Power Coefficient of War Ship Anchor (함정 묘의 파주력과 파주계수에 대한 이론적 고찰에 관한 연구)

  • Lim, Bong-Taek;Ko, Jae-Woo;Kim, Byoung-Suk
    • Journal of Navigation and Port Research
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    • v.39 no.1
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    • pp.1-6
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    • 2015
  • In this study, with the awareness of the limitations set in the currently operated calculations of holding power and the holding power coefficient of anchors of naval ships due to its simple application of a specific value, various factors that impact the holding power and its coefficient were verified based on existing data analysis of literature research and numerous experiment results from anchor manufacturers, research institutes and academic community in order to overcome the aforementioned limitations. In addition, holding power and holding power coefficient were compared and analyzed by the shape of anchors. As a result, we came to know that the holding power of AC-14 type anchor is stronger than that of ASS type anchor or U.S. Navy Standard type anchor which makes it possible to reduce the weight of the anchor and therefore ease the process of naval shipbuilding. Furthermore, we confirmed the fact that U.S. Navy Standard type anchor does not react sensitively to the weight change of the anchor. Lastly, we found out that Danforth type anchor's holding power coefficient is in inverse proportion to the weight. Moreover, instructions for managing anchor are arranged easily for your information. The results of this study is expected to provide anchor - operating naval crew with a reliable theoretical basis pertaining to an anchor's holding power and its coefficient and contribute much for the safety of their act of anchoring.

Difference of holding power of concrete weight used in shellfish shell fishery by its shape characteristics (패류껍질어업에서 사용 중인 멍의 형태적 특성에 따른 고정력의 차이)

  • LEE, Gun-Ho;CHO, Sam-Kwang;KIM, In-Ok;CHA, Bong-Jin;JUNG, Seong-Jae
    • Journal of the Korean Society of Fisheries and Ocean Technology
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    • v.54 no.1
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    • pp.25-31
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    • 2018
  • In this study, the differences of holding power according to the shape and weight distribution of concrete weight used in shellfish shell fishery were investigated through the experiments. To investigate the differences in shape, five bar-shaped concrete weights with the same length and different cross-sectional shapes were produced. The sectional shape of each weight was square, triangle, circle, small cross, and large cross (SQ, TR, CI, CR-S, CR-L). Ten rectangular parallelepiped weights with different bottom area and cross-sectional area were produced. To investigate the differences by the weight distribution, the holding power on the square model (SQ) with six 50 g weights at different positions was investigated. All the holding power was obtained by measuring the tensile force generated when the concrete weight was pulled at a constant speed on the sand. As a result, there were no differences in holding power between the ten rectangular weights. However, the experiment on weights with different cross-sectional shapes showed differences in holding power. The holding power was higher in the order of CR-L > CR-S > CI > TR > SQ. In the weight distribution test, the holding power was higher as the front side of the weight was heavier. Generally, the frictional force is the same even if the shape is different, when two objects have the same value in the weight and the roughness. On the other hand, it seems to have a large impact when the shape of the bottom is deformed in the course of pulling the object. Particularly, the larger the degree of protrusion like cruciform weights, the more the holding power increased while deeply digging the bottom. It is also likely that the holding power increases as the front weight increases.

The Comparative Analysis of Holding Pace and Decision Factors of Tractor in Korea and Japan (한.일 트랙터의 보유속도와 수요요인 비교)

  • 강창용;김남욱
    • Journal of Biosystems Engineering
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    • v.25 no.5
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    • pp.391-398
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    • 2000
  • This study was performed to analyze the holding pace and decision factors of tractor in Korea and Japan, which probably should be used for making master plan of agricultural mechanization. The logistic function is used for holding pace estimation of tractor, and log-log function for analysis of decision factors. The results of this study are as follows: First, the increasing rate of the total amount of holding tractor power in Korea has been over that in Japan during 1980∼、94 which is now, however, under Japan. So, it could be forecasted that the per tractor holding power in Japan will increase continuously, and will be over 30PS in the short run. Second, the most important one of decision factors to support tractor demand is agricultural income in Korea, but on the other hand Non-Agricultural Income in Japan. From these, the fast increase of total amount of holding power of tractor in Korea could not expected, because Korea Agriculture has some difficulties to increase Agricultural Income. There are differences on the holding pace and decision factors of tractor between Korea and Japan, therefore, the plan of agricultural mechanization should be made in accordance with self-features.

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640TEU 컨테이너서느이 묘박설비와 외력크기의 비교에 대한 고찰

  • 강봉석;정효진;오지설;박은아;박인성;김세원
    • Proceedings of the Korean Institute of Navigation and Port Research Conference
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    • pp.151-158
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    • 2000
  • 1. Instruction. 2. Investigation about holding power in Da san mooring area. 3. Weather condition in Da san anchorge. 4. Calculation of Externer power. a. Calculation of Container ship' holding power in mooring. 6. Comparison of Container ship' External power and holding power. 7. Conclusion.

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Analysis on Attraction Power and Holding Power of Exhibition Areas at Science Museum(II) - Focused on Analysis on Exhibition Method of Exhibition Spaces - (과학계 박물관 전시공간의 흡입력과 지속력 분석(II) - 전시영역별 연출매체의 분포특성 분석을 중심으로 -)

  • Lim, Che-Zinn;Choo, Sung-Won;Park, Moo-Ho
    • Korean Institute of Interior Design Journal
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    • v.20 no.4
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    • pp.174-182
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    • 2011
  • This study analyzed visitors' behaviors in the viewpoint of Attraction Power and Holding Power of exhibits on the basis of exhibition layout of real science museums. Through the analysis, the study grasped efficiency of analysis index and exhibition environment elements which might have an effect on planning the exhibition space of a large-scale museum and producing detailed ranges of exhibition. The main indicators used are: 1. Attraction Power: it indicates the relative incidence of people who have stopped in front of an object/exhibit during the exhibition tour. It is calculated by dividing the number of people who stop by the total number of people who have visited the museum or gallery. 2. Holding Power: it measures the average time spent in front of an information/communication element. It is calculated by dividing the average time of stay by the time "necessary" to read an element. As a result of analyzing the exhibition areas of National Science Museum (Daejeon) and National Museum of Emerging Science and Innovation(Tokyo), the Holding Power was found to be relatively lower than the Attracting Power. This means that 3.5 out of 10 visitors stop in front of the exhibit in 6 exhibition areas, and among these, only 1/10 is used when compared to the user required time of the exhibits. In other words, like the method of deriving an analysis index, the stage of viewing can be categorized as Attracting Power and Holding Power, and because the stage from Attracting Power to the stage of Holding Power are strongly linked, it shows that it is not easy to display a meaningful result. Except, the general distribution of Attracting Power was shown to be high from the entrance area of the exhibition hall based on the standard of viewing sequence. Also, the Holding Power became sequentially lower according to the sequence of exhibition viewing and displayed a meaningful interrelationship with the distribution ratio of island exhibits. In the case of island exhibition method, it is less influenced by the movement flow of visitors when compared to the wall type method of exhibition and can be understood as an exhibition method that provides spatial chances enabling stopping and viewing.

Experimental Study of Embedding Motion and Holding Power of Drag Embedment Type Anchor (DEA) on Sand Seafloor (해성 모래지반에서 Drag Embedment Type Anchor Model의 파지 운동 및 파지력에 대한 실험적 연구)

  • Lee, Jae-Hoon;Seo, Byoung-Cheon;Shin, Hyunk-Young
    • Journal of the Society of Naval Architects of Korea
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    • v.48 no.2
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    • pp.183-187
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    • 2011
  • As larger the commercial vessel is, and rougher the marine environment becomes nowadays, drag embedment type anchor (DEA) of more stable performance and higher holding power is requested to be applied on the vessel. But, the performance of DEA has not become well known to academy and industries so far, that the basic study of DEA performance and holding force for the development of new DEA of higher performance is insufficient that required. In this paper, three types of same holding category DEA model (HALL, AC-14, POOL-N, scale 1/10), which are generally applied on the commercial vessel nowadays, were tested by being horizontally dragged on the test tank, on which sand was being floored with sufficient depth, and measured the holding force of each anchor simultaneously using load cell and D/A converter. With the test results, the embedding motion was analyzed to have three different stages and the holding force of each anchor was analyzed with respect to the anchor geometry, such as shape and weight of each type of anchors, and final embedding depth.

Analysis on Attraction Power and Holding Power of Exhibition Areas at Science Museum - Focused on Analysis on Exhibition Method of Exhibition Spaces at Gwacheon National Science Museum - (과학계 박물관 전시공간의 흡입력과 지속력 분석 - 국립과천과학관 전시영역의 연출매체 분석을 중심으로 -)

  • Lim, Che-Zinn;Choo, Sung-Won;Park, Moo-Ho
    • Korean Institute of Interior Design Journal
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    • v.20 no.1
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    • pp.165-172
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    • 2011
  • Visitors' behaviors within an exhibition space are a substantial means to grant spatial arrangement and validity of exhibits. Therefore, the study analyzed visitors' behaviors in the viewpoint of attraction power and holding power of exhibits on the basis of exhibition layout of real science museums. Through the analysis, the study grasped efficiency of analysis index and exhibition environment elements which might have an effect on planning the exhibition space of a large-scale museum and producing detailed ranges of exhibition. The main indicators used are: 1. Attraction power: it indicates the relative incidence of people who have stopped in front of an object/exhibit during the exhibition tour. It is calculated by dividing the number of people who stop by the total number of people who have visited the museum or gallery. 2. Holding power: it measures the average time spent in front of an information/communication element. It is calculated by dividing the average time of stay by the time "necessary" to read an element. As a result, It was expected that attraction power and holding power of exhibit would be increased when moving line of seeing was inductive. However, when the traffic movements of seeing was inductive, repetitive seeing of exhibit was almost never realized and visitors had a strong tendency which viewed on their way of moving without viewing on their way of stopping. On the other hand, it may mean that density of exhibit is low or size of exhibition space is small that most of exhibits within exhibition space have high attraction power and holding power. As Gwacheon National Science Museum, when a museum is composed of many large-scale exhibit halls, it should be formed by separating the main moving line of seeing from the optional moving line of seeing through visitors' natural choice of exhibit and proper inducement of moving line of seeing. In such structure, exhibition environment of the main moving line has an effect on attraction of exhibit and the use of optional moving line acts as a factor to increase attraction. In addition, it is thought that attribute of exhibit and proper arrangement of rest space within exhibition space will increase holding power of exhibit.

A Study on the Holding Power Coefficient of AC-14 type and ASS type Anchor in Actual Ships (주묘 사례를 통한 AC-14형과 ASS형 앵커의 파주계수 비교에 관한 연구)

  • Jung, Chang-Hyun;Lee, Yun-Sok;Kim, Jong-Sung;Kong, Gil-Young
    • Journal of Navigation and Port Research
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    • v.35 no.8
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    • pp.613-618
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    • 2011
  • Vessels on anchoring are sometimes dragged due to the increased external forces. For preventing the dragging, it is required to enhance the holding power of the anchor. The holding power depends on the type and weight of the anchor and the seabed condition. Especially, the holding power of AC-14 type anchor is known to be 2~2.5 times bigger than that of ASS type anchor. However, these coefficients was determined nearly by the result of the model test, so there is a need to verify that by sea trial. Therefore actual dragging case was analyzed and then compared with the coefficients in use, it was found that the two of them are much alike.