• Journal of the Korean Society for Marine Environment & Energy
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• v.9 no.2
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• pp.92-97
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• 2006

Hull forms of a high speed small boat have been developed through numerical studies. A round bilge type hull form has been drived form a using chine hull form with HCAD, a hull form variation software. Wave resistance and the flow fields around the ships have been computed using well-known software, WAVIS. This software employs Rankine source method with non-linear tree surface condition as well as dry transom boundary conditions. The round bilge hull form showed better resistance performance than to the chine hull form for the whole speed range. However, considering the building and labor costs of the small shipyard, the chine hull form has been selected and its wave resistance characteristics has been improved by modifying the bow regions and applying the stem wedge. It is found that the effect of stem wedge is quite satisfactory to improve the resistance characteristics of high speed chine hull form.

• Journal of Ocean Engineering and Technology
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• v.17 no.5 s.54
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• pp.88-94
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• 2003

A series of tests of 5 model ships, selected from a data survey of 10 Gross Tonnage actual fishing boats, were performed in two circulating water channels (Chosun University in Korea and WJFEL in Japan), in order to develop the basic hull form of a 25 knots-class fishing boat. Resistance tests, trim and sinkage measurements and wave pattern observations etc., were included in each I1wdel test, and the model test results were compared and analyzed. The result was as follows: P-4 hull form ship changed into Deep V type bow is the best hull form with good performance, especially with regard to ship's resistance efficiency.

• Special Issue of the Society of Naval Architects of Korea
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• 2009.09a
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• pp.65-70
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• 2009

In case that tug boat pushes side structures of other large vessels to maneuver, it is required that contacted side structures of the maneuvered vessels have enough structural safety against tug push loads. The objective of this study is to evaluate the structural effect of carling which is installed between side longitudinal stiffeners. A comparative study of side structures with carling and without carling is performed to evaluate the effect of carling member by both FE analysis. According to the result, it is found that the carlings play effective role in the strength of side plates and side longitudinal stiffeners against tug push loads.

• Journal of the Korean Society of Marine Environment & Safety
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• v.20 no.5
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• pp.552-557
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• 2014

The objective of the This study is to access the speed performance employing the sea trial test and CFD with the our own designed and manufactured one-man boat. The overall design process including hull form design was explained. The sea trial was carried out with a manufactured boat in the clam sea. Brake power at the design speed of a boat through the sea trial was measured as 1680 W. The flow computation was conducted considering free surface and dynamic trim using a commercial CFD code(STAR-CCM+). The result of computation provided the information that residual resistance is bigger than fraction's at design speed. The total efficiency were predicted based on the sea trial and CFD. The Total efficiency was divided into shaft efficiency and quasi-propulsive efficiency. By using quasi-propulsive efficiency, it becomes possible to predict speed performance of boat in future. The results can provide information regarding hull form design, performance analysis and development of a boat in future.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2014.05a
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• pp.413-416
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• 2014

Recently, demand for various leisure sports gradually increases, as people's sense of values changes into leisure-centered one according to the change of given social circumstance and the change of customer needs all over the world. The actual condition is that an interest and participation rate especially in water leports during the summer increases. And needs for various hull design of standardized boat for water leisure increase. Therefore, this paper is intended to develop a recommendation system to design a boat for water leisure by using the collaborative filtering technique in order to make it possible to actively cope with the change of various customer needs for hull design. To this end, emotion relating to kayak design was selected through consumer survey, and emotion was derived by factor analysis and assessment, and then a kayak design layout in the aspect of customer's emotional preference was presented. Besides, an analysis was made according to the elements such as hull, body, and propulsion system of kayak in order to select emotional words according to the kayak design reflecting user's preference, and then a boat model for water leisure in conformance with user's preference was presented.

• Journal of the Korean Society of Marine Environment & Safety
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• v.17 no.3
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• pp.269-274
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• 2011

The purpose of hull stress monitoring system(HSMS) is to lead hull structure to be safer at lower cost. We proposed a hull stress monitoring system for leisure boats using fiber-optic bragg grating(FBG) strain sensor. Fiber optic sensors are well suited for structure monitoring system, due to their ability to withstand harsh environments, immunity to electromagnetic interference, and reduce cabling installation cost when employing wavelength multiplexing. This paper presents an overview of current research and design of hull stress monitoring system for leisure boats.

• Journal of the Korean Society of Marine Environment & Safety
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• v.19 no.6
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• pp.674-680
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• 2013

As the range of marine leisure activity gradually expands to ocean-going, a habitable cruise boat has been getting the limelight. Advanced countries in the marine leisure industry in Europe and North America have already secured their competitiveness in designing and building cruise boats by elegant design, ergonomic structure and fuel efficiency through the adoption of light-weight hull materials. In contrast, mostly small power boats are developed and built in Korea, and GFRP take up the most of hull materials. This study inquired into the design and characteristics of a 50ft-class CFRP that ocean-going is possible. The hull-form of the CFRP cruise boast were analyzed to propose a hull form for the designed ship (MMU-C.B), and based on that, the design model of the MMU-C.B was built. Finally, the MMU-C.B's characteristics of the resistance performance and hull-planing were found by comparative reviews with the results of model tests of GFRP pleasure yachts.

• International Journal of Naval Architecture and Ocean Engineering
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• v.4 no.2
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• pp.162-171
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• 2012

A method of hydrodynamic discrete sources is applied for two-dimensional modeling of stepped planing surfaces. The water surface deformations, wetted hull lengths, and pressure distribution are calculated at given hull attitude and Froude number. Pressurized air cavities that improve hydrodynamic performance can also be modeled with the current method. Presented results include validation examples, parametric calculations of a single-step hull, effect of trim tabs, and performance of an infinite series of periodic stepped surfaces. It is shown that transverse steps can lead to higher lift-drag ratio, although at reduced lift capability, in comparison with a stepless hull. Performance of a multi-step configuration is sensitive to the wave pattern between hulls, which depends on Froude number and relative hull spacing.

• Proceedings of the Korean Society for Agricultural Machinery Conference
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• 1993.10a
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• pp.148-157
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• 1993

A study was conducted to evaluate the effect of enamel coating on boat hull drag. The results were compared with drag required for varnished uncoated boats. Models of rice barge and fishing boat were used in this study. The speed range of 0.6 to 1.5㎧ at different loads varying from 6 to 9 kg for rice barge and 4.6 to 6.4kg for fishing boats were used during testing. The total weight of the coated and uncoated boats were kept the same. It was observed that the drag force required by the coated boats was less than identical uncoated ones at all speeds and loads. For both uncoated and coated the drag required increased with speed. The maximum recorded reductions in drag were 26% for the rice barge and 28% for the fishing boat model.

• 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.