• Title/Summary/Keyword: Offshore launching

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Influential Parameters on Offshore Jacket Structure Launching (해양 자켓구조물 진수 영향인자에 대한 고찰)

  • 조철희;김경수;김재환;이수훈
    • Journal of Ocean Engineering and Technology
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    • v.15 no.2
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    • pp.141-147
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    • 2001
  • The launching process is one of the most critical operations for large structure in offshore installation. Since as the size increases it limits the availability of offshore crane facilities, the large jacket structures are often installed by launching. As the structure approaches to tilt beam, it reaches critical load, and there are parameters to affect on launching procedure. The major influential parameters are trim, draft of barge, center of gravity, center of buoyancy and reserved buoyancy of jacket. As increasing of trim and draft, structural loads tend to decrease. The trim is found to be more contributing than draft on structural loads. Therefore the trim should be increased so as to decrease structural loads and to avoid stalling of structure and submergence of stern. During the launching process, the distance between jacket and seabed should be investigated which differs from the amount of reserved buoyancy and launching condition of barge. In this paper the effects of parameters on launching process are numerically investigated.

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An Upending Stability for Offshore Jacket (대형 해양 자켓의 직립 안정성 고찰)

  • Jo, C.H.;Kim, B.H.;Jeong, H.
    • Proceedings of the Korea Committee for Ocean Resources and Engineering Conference
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    • 2003.05a
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    • pp.203-207
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    • 2003
  • As the upending is one of the critical steps in the installation of offshore structure, datail procedure of upending operation is studied in the paper. For larger offshore structure installation, launching method is often applied. However after launching, the upending process is to be followed. To ensure successful upending operation, datail process is analysed considering various factors affecting on the operation including reserved buoyancy, free flotation position, seabed clearance, ballast and hook load. To investigate the influence of each factor on the procedure, twelve numerical jacket models with various dimensions are simulated and studied. From the study, it is revealed that the increase of buoyance and decrease of self weight generate a large seabed clearance. The law seabed clearance during flooding creates higher hook load and height. The paper also introduces a guideline for the related structure design and construction with the effects of contribution factors in the upending operation.

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Analytical Approach of Sliding Installation Method with Spar Structure

  • Lee, Jong-Hyun
    • Journal of Navigation and Port Research
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    • v.35 no.7
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    • pp.575-580
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    • 2011
  • It is important to understand the trajectory of structure in launching process because of the short time of launching process may result in unexpected accidents or damage to structures. The high risk of structural failure is not avoidable without the fully comprehension of changing forces in launching procedure. The commercial software can evaluate the motion of launching event in calm water condition but there is the limitation of research application because of the programmed commercial software. The launching process of the spar hull is suggested with stage concept that is divided into 10 stages in time domain. A force equilibrium diagram is derived for each stage where the changes of force vector and motion characteristics take place. In particular, the effects of changes in buoyancy and drag force due to the progressive submergence of the spar hull are taken into account by means of a touch length concept. The results contained in this paper provide the valuable information of the trajectory motion evaluation with suggested methods in spar launching process with sliding barge. Furthermore, the presented stage concept and touch length concept will provide basic knowledge for understanding launching process and help to develop further research area for launching analysis.

A Historical Consideration on the Evolution of Competition in Offshore Fisheries (근해저인망류어업에 있어서 업종별 경합관계 형성에 관한 사적고찰)

  • 김병호
    • The Journal of Fisheries Business Administration
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    • v.35 no.1
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    • pp.23-56
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    • 2004
  • The offshore trawl fishery is seeking its survival way to overcome current management conditions in red, resulted from the bilateral agreement with China and Japan. However, this movement magnifies conflicts between fisheries on the contrary and it is thought to be impossible to get over current situations. For all that, this study is aimed at investigating how this current situations have occurred. The management freedom as response to the change in fishing conditions of a certain fishery, in case of Korea, is affected by institutional regulations. The example of this is controls on fishing gears, fishing vessels, and fishing grounds. The most exposure of this control is a segmentation of institutional fisheries. The initial segmentation of the offshore trawl fishery in Korea was occurred in the period of Japan's colonization when the degree of use of fishing grounds was limited geographically. At that time, fisheries were divided by fishing areas, but it did not divide the fishery itself. The large - sized fishing vessels were developed politically to be more competative to Japanese fishing vessels since 1950s. During this time, the trawl fishery was merged into current Eastern trawl fishery and South - Western trawl fishery. It was also inevitable to divide into the pair trawl and single trawl fishery as a result of the physical mergency between Western trawl and Southern trawl fishery. In order to develop the trawl fishery, new licenses were issued on the shrimp trawl fishery, through which it was expected to boost the trawl fishery. As opposed, the shrimp trawl fishery was changed into the mid - sized trawl fishery, targeting on the eastern fishing areas and the large - sized trawl fishery was developed since the late of 1970s with the development of filefish processing industry. The large trawl fishery that led in development of offshore trawl fishery since the late of 1950s was started to divide into a pair trawl and single trawl according to the fishing method and capital power. It finally became an institutionally independent fishery in 1980s, respectively. Looking into these historical process, the segmentation of the trawl fishery is thought as a result of the lack of long - term perspective and as a production of trial and error resulted by unprepared policy. As a result, these segmentation of fisheries roles as critical obstacles in harmonization of fisheries and in overcoming of current situations. Therefore, the review of this institutional segmentation of the offshore trawl fishery should be taken for an optimal redistribution of fishing grounds suits with business and fishing technology. For this, the fishery must be divided into large capitalized fishery and small - mid fishery with consideration of capital, fishing method, and the condition of use of fishing grounds. In addition to this, by limiting outline of fishing ground that the large fishery can harvest, it must allow for the small - mid fishery to catch with its own boundary. Furthermore, by launching buyback programs on the trawl, eastern trawl, pair trawl, it can provide broader fishing grounds where the fishery can harvest with management freedom.

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A Study on the Determination of Minimum Welding Condition Based on Structural Strength under Launching for Tandem Blocks (선체 블록 진수 시 필요한 최소 용접 구조 강도 평가에 관한 연구)

  • Myung-Su Yi;Joo-Shin Park
    • Journal of the Korean Society of Marine Environment & Safety
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    • v.28 no.7
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    • pp.1267-1273
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    • 2022
  • Although the Korea shipbuilding industry has recently been receiving most of the orders for ships in the world, production processes are being disrupted due to a shortage of manpower at the production site. This is because the workers quit the shipyard as both work and wages were reduced due to the long slump in the shipbuilding industry. The main reason for the increase in orders was the large-scale orders for Qatar LNG carriers, and the situation in which the technical specifications required for ships are becoming more complex is also working to an advantage. Because the contract delivery time is of utmost importance for ships, the dock launch plan is the most important management item among the shipyard's major processes. The structure to be built in the dock may be a hull that has left the design work or a finished vessel, and in some cases, it is often at the level of some blocks of the hull. When launching, the hull is affected by the hogging or sagging moment due to the fluid force, and securing the safety of the structural strength of the block connection is of utmost importance. In a normal process, the connecting member launches after welding has been completed, but in actual shipbuilders, quick decision-making is needed on the conditions for securing structural safety to comply with the docking schedule. In this study, a detailed analysis method and applicability using a bending stress evaluation method and finite element analysis modelling were analyzed to rationally judge the above-mentioned problems from an engineering point of view. The main contents mentioned in the thesis can be used as good examples when conducting similar structural strength evaluations in the future.

A Study of Overseas Manufacturing Factories of Garment Vendors and the Influence of Korean Wave over the Sourcing Area - Focused on Vietnam and Indonesia - (의류무역회사의 해외생산공장 현황과 소싱지역의 한류 영향에 대한 연구 - 베트남과 인도네시아를 중심으로 -)

  • Choi, Hei-Sun;Lee, Eun-Young;Kim, Ji-Eun
    • Journal of the Korean Society of Costume
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    • v.62 no.4
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    • pp.149-163
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    • 2012
  • This study reviewed current facts on overseas manufacturing factories of garment vendors that were launched in the countries that have a great influence of the Korean Wave, and investigated the influence of Korean Wave in its sourcing area. By doing so, this study aims to present basic data in order to help fabric and garment vendors to enter into the fashion markets of different countries through a local network. For data collection and analysis, Windows SPSS 19.0 was used for frequency analysis of the facts and figures of the local manufacturing factories. In-depth interviews regarding the current facts on local manufacturing factories and the influence of Korean Wave were conducted with 16 Korean garment manufacturing factories in Vietnam and 9 in Indonesia among the overseas garment companies that were registered in the Korean Apparel Industry Association. Through the interview, it was found that new companies should investigate custom tariffs, salary level of the local employees, and infrastructure prior to launching above all. Also, as a result of analyzing competitors and competitive advantages, good treatment of local employees and a good labor environment were noted the most. As for the influence of the Korean Wave, the image of Korea was positive and favorable, but it did not directly affect the preference for Korean companies. After investigating the obstacles that prevented the entrance into local markets, it was found that the rise in the salary level was the biggest hindrance.