• Journal of Ocean Engineering and Technology
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• v.21 no.3 s.76
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• pp.40-45
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• 2007

This study was performed to investigate the effect of various propeller tunnel shapes on the propulsion performance of a fishing boat. The propeller tunnel reduces the problem resulting from the open propeller accidentally catching the waste net and cable on the sea, as well as increasing the cruising speed. For 3 different tunnel geometries, the model test is conducted in the circular water channel, and the potential based panel method was applied to analyze the hydrodynamic characteristics of propeller. Also, both results are compared with each other to represent the difference between results of the model scale test and the potential theory. It is expected that these results could be referenced in the design of the propeller tunnel in consideration of the hydrodynamic interaction between the propeller and the tunnel.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.59 no.3
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• pp.206-214
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• 2023

Fish school monitoring technology is utilized for various purposes, such as boat fishing and resource surveys. With advancements in information and communication technology, this technology has expanded its application to remote areas. Its significance has grown in fishing sites, particularly for improving the efficiency and cost-effectiveness of set-net fishing. Set-net fishing gears are not limited to coastal areas, but are also installed in inland and remote sea regions. Consequently, fishermen require technology that allows them to quickly transmit information about approaching fish schools and enables them to perform long-term monitoring. The development of remote monitoring technology for set-net fish schools must consider crucial design factors such as communication range, transmission speed, power consumption of information modules, and operational expenses. In this study, we developed a low-power remote monitoring module for set-net fish school based on WCDMA. The module was specifically designed to minimize power consumption, allowing for communication over long distances and extended operation times in set-net fishing applications. Furthermore, we developed a web server software application that enables remote access to fish schools and provides real-time weather information. The performance of the developed module was evaluated through set-net fishing site application and experiments with moving ships on the sea. The experimental results demonstrated that the remote monitoring system, consisting of the developed low-power remote monitoring module for set-net fish school based on WCDMA and a fish finder, had an average power consumption of 4.6 W, a maximum communication range of 22.84 km, and a data transmission and reception rate of 98.79%. The maximum fish school information transmission and reception rate was 97.26%

• Journal of the Korean Society for Marine Environment & Energy
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• v.9 no.4
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• pp.253-262
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• 2006

In this paper, collision analysis is carried out between two FRP fishing boats. A computer simulation with finite element method is used to accomplish this objective. At first, a detailed geometric model of the boat is constructed using 3-D CAD program. The formation of a finite element from a geometric data of the boats is carried out using HYPERMESH that is the commercial software for mesh generation and post processing. Twelve collision configurations are established by combining two kinds of contact angle($90^{\circ},\;135^{\circ}$) and three different speed(5, 10, 15knot) for small and large boats. Collision analysis is accomplished using DYNA3D. Stress distribution and deformation shape are investigated for each collision condition. In general, $90^{\circ}$ collision angle generate larger stress than $135^{\circ}$ case and the collision for two moving boats showed larger maximum stress than the case that one is moving and the other is stationary. When analysis is carried out until 150ms contact parts of two boats are broken for 10 and 15knot collision speed, in which maximum stress is larger than ultimate strength of the material.

• Journal of Advanced Marine Engineering and Technology
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• v.41 no.4
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• pp.316-322
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• 2017

The primary objective of the current study is to develop outstanding hull form on resistance performance by using numerical analysis code. Model tests were conducted to assess the resistance performance of the developed hull form. The investigation of an existing vessel was performed for validating the actual ship design based on the drawing. The operating displacement and speed were mainly confirmed through investigation of the existing vessel. The resistance performance of the existing vessel was analyzed using numerical code. The developed vessel was derived through studies on wave improvement of the bow shoulder, the balance of displacement distribution, the modification of the frame shape, and the size and shape change of the center skeg. Based on the results of a computational fluid dynamics analysis, the resistance performance of the developed vessel showed an improvement of 15% over the existing vessel at a speed of 11 knots. Resistance tests were conducted to evaluate the performance of the existing vessel and the developed vessel in the towing tank. Finally, the effective horsepower of the developed vessel showed an improvement of 17% over the existing vessel.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.54 no.1
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• pp.1-11
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• 2018

This study was conducted in order to improve fishing gear for existent net of the anchovy boat seine. Field experiments were performed to observe geometry of nets by catcher boats. When the distances between the two ships were 100, 300, and 500 m, and the speeds of towing nets were 0.6, 0.9, and 1.2 k't, respectively. The vertical opening and actual opening of each part of the existent net was as follows: the middle part of the wing net, 12.9-26.6 m, 19-39%; the entrance of the inside wing net, 23.3-35.3 m, 40-60%; the square and bosom, 18.4-24.2 m, 37-49%; the entrance of the bag net, 19.0-23.3 m, 79-96%; the flapper, 13.2-15.3 m, 142-161%; and the end of the bag net, 13.2-15.7 m, 51-61%. The actual net opening of each part of the existent nets used in this study was lower than that of the design net height, due to the low net height of the wing net and the inside wing net, it limited a range of the net height of the square and bosom. The opening of the entrance of the bag net caused the net pocket shape and inflated some parts of the nets. The tension of towing nets was measured between 4.4 and 11.0 tons, and it is necessary to reduce the structure and improve the structure of the bag net.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.52 no.4
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• pp.347-355
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• 2016

In this study, a new designed propeller was applied on 24 ton class squid jigging vessel to reduce of fuel consumption. The selected squid jigging boat was under construction at the shipyard to determine the resistance of the hull through the model experiment. The propeller design was carried out by using the experimental data and ITTC procedures. Sea trials were performed by measuring the speed and the horsepower required by the condition of five power levels of engine load, namely 70%, 80%, 90%, MCR and maximum engine power. The speed and delivered horse power were compared between the conventional propeller and the new design propeller. Delivered horse power by installing the new propeller takes 90% engine load at start-up conducted by decreased 9.06%. The measuring speed is increased up to the 0.6 knots in the low-speed range to high range. This study showed that only the design and installation of a new propeller can improve the propulsion efficiency of the boats; furthermore, reduce fuel costs can be achieved at the same time by improving the increased cruising speed.

• Proceedings of KOSOMES biannual meeting
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• 2005.05a
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• pp.155-159
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• 2005

Analysis target ship is not introduced yet in domestic as steel yacht that is getting into the spotlight by leisure life in Australia or Japan. Sailing yacht or Yacht for leisure time made of FRP into controlling power fare mainly and the design and made of latest fishing boat and something of domestic is consisting mainly. To need investigated for concept is various kinds overall strength as that use mainly steel wire material structurally of steel yacht by small crafts about Longi strength, Transe strength portion even of design safety factor at subject to do Rule's allowable stress enough stable structure accomplish. But it is assessment of part intensity that become refer to most in small size ship.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 2012.06a
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• pp.225-226
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• 2012

Recently, In the domestic is used mainly fiberglass reinforced plastic(GRP) and is built for maritime leisure vessel & structures. but it less attention is insufficient for ship of structural strength assessment of maritime leisure vessel. Therefore, The structural strength evaluation suitable for the domestic situation formulate and is applied to domestic regulations of "Guidance for Recreational Crafts" of Korea register of shipping(KR) & "Reinforced plastic line structure standards" of Ministry of Land, Transport and Maritime Affairs. the structural design and finite element analysis(FEA) to ensure the reliability.

• Journal of the Korean Magnetics Society
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• v.24 no.6
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• pp.197-201
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• 2014

As the importance of rare metal is increasing globally, Japan introduced the concept of Strategic Elements in 2004, and started Strategic Elements Project in 2007. The Goal of this project run by MEXT (Ministry of Education, Culture, Sports, Science and Technology) is to develop high-function materials and components that do not use rare or harmful elements by studying the role and characteristics of the elements that compose materials and components and decide their functions and characteristics. In September 2010, Japanese coast guard arrested a Chinese fishing boat near Senkaku Islands (Diaoyudao Islands by China), which escalated to the territory issue and eventually a big diplomatic and economic conflict. In order to put pressure on Japanese Government, China used an economic option, which is the ban of rare earth export to Japan. This incident doubled Japan's motivation to develop Strategic Elements and put more efforts into this Project. MEXT set the following three research areas in February 2012: Study of alternative materials using sufficient and harmless elements, Study of applications for the high-functions of Strategic Elements, Study of practical design for components using Strategic Elements. Through a course of gathering the opinion of professionals, MEXT settled down with the following 4 research and study areas for the Strategic Elements Project in June 2012. 1. Magnetic materials to replace Dy, Nd. 2. Catalyst/Battery materials to replace Pt, Rh/Li, Co. 3. Electronic materials to replace In, Ta. 4. Structural materials to replace Nb, Mo. This paper deals with the first area and reviews the results of the research and study as of now.