• Journal of the Society of Naval Architects of Korea
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• v.46 no.1
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• pp.10-23
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• 2009

Korean small coastal fishing boats have the different kind of fisheries and customs against Japanese fishing boats. Those bring some influences on the principal parameters of hull form. In same displacement, Korean small coastal fishing boat has generally shorter length, draft and wider breadth than Japanese fishing boat. Furthermore, even though the parameters of each hull form are similar, it is known that the resistance performance of Korean small coastal fishing boat is worse than that of Japanese fishing boat. In this study, the representative hull forms of Korean and Japanese small coastal fishing boats are selected and compared to evaluate the resistance performance of Korean fishing boat in low-speed range. The hull form of the Korean fishing boat is modified as comparison with that of the Japanese fishing boat to confirm the partial characteristic differences between the hull forms and the resistance performances. The representative partial characteristics of hull form are the gradient of chine line, keel shape and stern length. The resistance performances of the modified hull forms are evaluated by INHAWAVE which is one of CFD program and model tests in towing tank. The results of the present study will be used to improve the resistance performance and to develop the practical hull form of Korean small coastal fishing boats as principal data in the preliminary hull form design of fishing boats.

• The Journal of Fisheries Business Administration
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• v.42 no.2
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• pp.31-45
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• 2011

Costal fisheries use small boat. The boats are frequently substituted with newly made boat or proper boat. When the boat which is substituted with another one after the fixed date for compensation is estimated for fisheries loss by public project, it is matter that which boat is the object for estimating average catch of fish. There are three ways in practical business. They are based on the date of spot probe, the date of conference for compensation and fixed date for compensation. In case of applying the first and the second ways, as the object of compensation is not fixed, there is problem that estimated result can be changed depending on changing boat tons even after the date of spot probe and the fixed date for compensation. Most of all, these ways are against Attached Form No.4 of the Enforcement Ordinance of Fisheries Law which regulate to calculate average catch of fish applying result of fishery for retroactively counted 3 years from the year before the year in which administrative measure day is. The other side, in applying boat tons based on the fixed date for compensation, estimated result of compensation will not change even boat substituted after the fixed date for compensation. Even though applying tons based on the fixed date for compensation, a problem still remains. If the boat get bigger after the fixed date for compensation, the then boat size must be applied for calculating average catch. But the boat get smaller, the changed boat size must be applied. Because changed small boat would be damaged less than the previous boat. And decrease in catch by changing boat into small one is not due to the project but due to the personal responsibility. This will help to increase objectivity and reliance on the compensation result. As the other objects are fixed based on the fixed date for compensation in the Act on Acquisition and Compensation of Land and Others for Public Project, it can be balanced with other object.

• Journal of Ocean Engineering and Technology
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• v.22 no.4
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• pp.78-83
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• 2008

In recent years, small boats used for marine leisure have been steadily increasing because of the increase in national income and the desire for marine leisure. But the repair of such small boats in dry dock has pointed out many faults in small FRP-shipbuilding in terms if workspace and manpower. Lifting a boat from the water to land is done with a crane or by hand using a sling around the bottom of the boat. But dry dock work is limited by the scale of the boat, which corresponds to the crane capacity, with carelessness making it possible to capsize a boat and endanger life. The purpose of this study was the development of a marine docking system that would improve economical efficiency and safety, for which we carried out concept design, model tests, structural analysis, etc.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.35 no.3
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• pp.323-327
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• 1999

Most of the underwater noise emitted by small fishing boat are owing to vibration of main engine and generator etc.. This paper describe on the spectrum analysis of underwater noise by engine generating in small fishing boat in order to build up comfortable environment for fisheries man and to reduce ambient noise. The obtained results are summerized as follows:1. When the underwater noise of 10ton class fishing boat measure and the frequency spectrum in varied revolution of engine 750, 900, 1000rpm analyze, the frequency pattern is similar to each other, the faster revolution of engine increase, the higher frequency spectrum level becomes. 2. In comparison of spectrum level of underwater noise between 10ton class and 14ton class fishing boat, the former level is higher than the latter. 3. Frequency spectrum pattern of two 14ton class fishing boat is similar to each other but spectrum level is a little difference, it is suggested to different by fitting condition of engine.

• Journal of Welding and Joining
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• v.32 no.1
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• pp.34-39
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• 2014

There are so many difficulties of melt bonding mainly applied for hull construction of a aluminum alloy small boat. For resolving this problem, Friction stir welding(FSW) in non-melting solid state welding Process generally is applied in the transport industry. This paper is studied the joining strength characteristics and macrostructure according to dissimilar aluminium 5000/6000 alloy joining for a small boat applied for this FSW technology. It is reported that difference of joining strength in accordance with the direction of rotation in case of friction stir welding between dissimilar metals(Al/Cu, Al/Fe) is also highly large. In this study, Test is carried out by making the specimen according to the direction of rotation of dissimilar aluminium alloy joining.

• Journal of Fisheries and Marine Sciences Education
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• v.23 no.3
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• pp.351-360
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• 2011

In order to reduce the casualties of fishing boats, the author analyzed the fishing boat accident on the 412 cases in Korean maritime safety tribunal for the 2005~2009, and then studied the relation between the weather element and the accidents. According to this studies, the occurring ratio of sea casualty for fishing boat in fog weather was appeared 1 boat per 1.6 days. It means that the restricted visibility condition gives the most influence on the fishing boat accident. The casualties in winter season from November to next January occurred 139(33.7%), and small boats less than 50tons broke out more casualties with 68.4%. From this we can find that small fishing boats are very deeply affected on the sea weather condition. According to the boat types for fishing the casualty of jig boat was ranked first, and collision accident account for first with 77.9% for the types of casualties. As mentioned above, most sea casualties for small fishing boats were resulted from the human factors such as poor watch keeping in invisibility and the bad sea condition, it is necessary for navigation operators and the manager to take more attention to the meteorological factors.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.16 no.12
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• pp.8447-8454
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• 2015

ISO 12215-5 standard describes allowable stress design specifications of monohull small boat with a length of hull between 2.5 m and 24 m constructed from fiber reinforced plastics, aluminium or steel alloys, glued wood or other suitable boat building material. If small boat hull is under 2.5m in overall length or nonstandard material is used as boat building material, structural reliability of small boat hull is assured by drop test specification, but not by structural design specification in accordance with ISO 12215-5. Drop test specification of boat hull can be applied to manufactured product. But it is difficult and complicated to apply drop test specification to structural design of boat hull. In this study, we present structural design method of polyethylene boat hull on the basis of longitudinal bending strength test specification.

• The Journal of Fisheries Business Administration
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• v.29 no.2
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• pp.163-175
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• 1998

The decrease of the fishery's business performance is due to the changes of environment-the increase of cost, the reduction of resources, the liberalization of import, the effectuation of the admiralty law Though the government has prepared the alternative policy to strengthen the competitive power of the fishery, fishermen should draw up a plan to improve the business performance. The problems of the small powered purse seine resulting from the small scale of the fishing boat is following. First, its catching activity in the sea is riskful. Second, the space to eat and to work is not enough. Third, the space to put the fish is not enough, it is hard to maintain the freshness of the fish. Therefore it is necessary to solve these problems for the scale of the fishing boat to have to be enlarged. The enlargement of the fishing boat to be required much expenditure of fund is the important investment decision to fishermen. The alternatives evaluation between the existing boat(defender) and the new boat enlarged with the new equipment(challenger) is necessary process to reduce the uncertainty of investment. The profitability of the challenger is better than that of defender due to the reduction of cost and the increase of revenue. Because the net present value of incremental cash flow is positive, it is rational for fishermen to accept the challenger.

• Journal of Ocean Engineering and Technology
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• v.22 no.4
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• pp.84-89
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• 2008

It is hard to find experimental data for a model test of small high-speed planning boats. It is difficult to verify the performance seen in a model test for a high-speed boat because the ship-model scale-ratio is very small and the flow velocity of the circulating water channel and the X-carriage speed of the towing tank are restricted. Therefore most hull-form designs for high-speed small boats depend on the sea-trial test result for similar boats or evaluation through numerical calculations. This study investigated the anti-rolling effect of the stern sub-body in a 50-knot doss planning boat. To carry out this work, new model test procedures were set up in the actual sea. Using this method, the anti-rolling effect of the stern sub-body was investigated. A stern sub-body attached to a planning boat was proved to be effective in reducing the roll and pitch angle.

• Bulletin of the Society of Naval Architects of Korea
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• v.21 no.3
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• pp.1-10
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• 1984

The computer programs of effective horsepower estimation of small fishing boat were developed, which was based on the statistical analysis of model test results. From the EHP estimation by these program and experimental model tests of practical fishing boats, the estimation accuracy was verified with maximum deviation of about 10 percent. Also, the EHP estimation accuracy was practically applied to initial design of four small fishing boats, and after the tank tests, the EHP reduction of the order of 15 to 25 percent was confirmed, as compared with existing ships. Moreover, a computer aided design procedure of fishing boat's hull form has been proposed in this study. The practical use of this procedure of fishing boat's hull form has been proposed in this study. The practical use of this procedure was demonstrated with the hull form design results of several fishing boats.