• Journal of the Korean Society for Marine Environment & Energy
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• v.16 no.3
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• pp.202-210
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• 2013

As incomes increase, interest in ocean leisure picks up. As a result, a lot of research and developments on hull form design and production of planing boats, mostly used for ocean leisure, are needed. Analysis in researches on resistance of planing boats shows that resistance characteristic of planing boats is different from resistance characteristic of general boats because the former is fast, and its wetted surface is very small. Using Savitsky formula widely used in the calculation of effective horse power in shipbuildingyards, and propulsion system and engine manufacturers, this study calculated total resistance of a research planing boat. Then it analyzed the flow characteristics of the planing boat through theoretical analysis and wind tunnel experiment, and computed air resistance and lift force by changes of speed and trim angle. It also compared and analyzed result of theoretical analysis and experiment of the ratio of air resistance to total resistance under variations of velocity and trim angle. When the study is used to estimate more accurate effective horse power, it is expected to remedy abuses of unnecessarily installing high-powered engine. As nature disasters due to abnormal changes of weather increase, interest in greenhouse gas grows. International Maritime Organization (IMO) legislated Energy Efficiency Design Index (EEDI) and Energy Efficiency Operational Indicator (EEOI) to reduce ship greenhouse gas emissions. But this index will be applied to over 400 tons ships, small ships, emitting more greenhouse gases than larege ships per unit power, will dodge the regulations. Thus, this study indicated a problem by calculating greenhouse gas emissions of an ocean leisure planning boat (a small ship), and suggested the need for EEDI of small ships.

• Journal of Advanced Marine Engineering and Technology
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• v.33 no.5
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• pp.762-769
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• 2009

A canoe is one of the most popular boats in leisure on the water. Generally canoe has been built by good wooden strips. And canoe built by FRP is used for business recently. But by the users' demands for good quality and the restriction to environmental pollution the wooden canoes are required for personal and canoe building business. The modern wooden canoes were built by the strip construction method are used typically. However it is not suitable for the mass productivity requires effective resource operations and managements of men, materials, times, and price. On this paper the new construction method, called the piling-up laminated construction method, is studied to building a canoe using the piling-up with the laminated wooden plates gives more productivity than the others. First a canoe with various curved surfaces is designed from 3D design system. And the hull of canoe model is divided horizontally to generating the laminated plates that will be converting real wooden plates available from the market and will be routed by the manufacturing machine. After the simulating and analyzing of piling-up with the laminated plates, the canoe is building with less times, less men, less resources, and lower price than other method, avoid of the requirements of additional building tools. On the next paper the constructing of a real canoe using the manufactured wooden plates will be studied.

• 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.

• Journal of the Society of Naval Architects of Korea
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• v.50 no.4
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• pp.240-247
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• 2013

Hydrodynamic characteristics of a planing craft are very sensitive to the hull form variations, especially when the craft navigates with high-speed. Therefore, we need to verify hydrodynamic performances of the craft during the process of hull form design. In this paper, motion performances of a 40ft class cruise leisure boat are evaluated by both model tests and theoretical analyses using two different methods. Model tests are carried out at calm sea and regular wave conditions using high speed towing carriage installed in SNU towing tank. Theoretical methods used are a empirical method proposed by Martin (1976) and a potential method based on Rankine panel (DNV, 2010). The results from the theoretical methods are compared with and verified by those of model tests. Results of empirical formula showed somewhat larger motion RAOs and resonant frequencies than those of model tests. Potential based method showed even larger discrepancies with the model test results. From the analyses of comparison results, we could confirm the limitation of each theoretical method and suggest the way of improvement for the better prediction of motion performances.

• Journal of the Society of Naval Architects of Korea
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• v.60 no.3
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• pp.175-185
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• 2023

Many small vessels such as fishing boats operate in the world's oceans; accordingly, interest in these small vessels' exhaust-gas problem is increasing. Research on the application of electric-propulsion technology has been steadily conducted; however, the subject is limited to research ships or leisure boats, while research on application efficiency remains insufficient. This study attempts to apply lithium-battery electric-propulsion technology to small ships. A gross tonnage of 9.77, a representative fishing boat, is to be redesigned as a fully electrified ship. Without changing the main cabin's dimensions and fuel tanks, the ship's propulsion system is redesigned based on a lithium-battery electric-propulsion system. In addition, the redesigned system is compared with the original sample ship's diesel-propulsion system for application-effect analysis. The results indicate that under controlled sailing conditions, the weight and volume of the electric-propulsion system are 9.5 and 10.5 times those of the diesel-propulsion system, respectively. These values indicate that the system cannot meet fishing boats' high endurance requirements. Therefore, under the existing technical conditions, applying the full lithium-battery electric-propulsion system to solve the problem of high emissions from fishing boats shows limited feasibility.

• Journal of the Society of Naval Architects of Korea
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• v.51 no.4
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• pp.291-299
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• 2014

In the design process of ship or its comprising components, the key to the successful design is how to guarantee the structural safety satisfying the international standard and regulation, which sometimes is not clear enough to cover the detail designs. This study deals with the design procedure for submersible viewing window installed in catamaran. As the window material, the Plexiglass, a type of reinforced plastic, is considered to satisfy the design requirements of international standard. Window thickness is calculated using geometric nonlinear finite element analysis, in order to take into account possible large deformation due to low stiffness of the Plexiglass, and the results are compared with those determined by the procedure specified in ISO12216. Finally, for the validation of proposed design, the pressure test had been carried out following the procedure specified in the standard, and structural safety was checked.

• Journal of the Society of Naval Architects of Korea
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• v.48 no.6
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• pp.479-489
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• 2011

Leisure boat and yacht should be designed to meet the domestic regulation and international standards as large merchant vessels do. Recently, each countries are encouraged to follow the regulation of International standards organization. Furthermore domestic organization has not yet announced the design rule and regulation for FRP-catamaran yacht design. Therefore, it has been required to make the regulation for domestic situations of FRP-catamaran. This study deals with the structural strength evaluation of 50ft catamaran by using finite element analysis. Design load of the regulation of International standards organization are compared with the regulation of Korea Register of shipping and Lloyd's Register.

• 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 Society of Marine Environment & Safety
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• v.30 no.4
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• pp.365-372
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• 2024

The South Korean marine industry is emerging as a significant market, driven by the growing popularity of various water leisure activities, including sailing. This trend suggests a rising demand for sailing yachts. Consequently, since 2022, the design and development of a 28ft sailing yacht have been ongoing, supported by the government and the Ministry of Oceans and Fisheries, to promote yachting culture in South Korea. The Velocity Prediction Program (VPP) analysis was conducted using WinDesign during the preliminary design stage to evaluate performance and determine design parameters. The hydrodynamic model used for this vessel is based on regression methods developed from years of experience in naval architecture and yacht research at the Wolfson Unit, providing reliable estimates for most modern yachts. However, owing to the lack of specific hydrodynamic data from towing tank tests or CFD numerical analysis, verification of the hydrodynamic model has faced some challenges. Additionally, an incomplete weight estimate resulted in variable VCG values, potentially affecting stability and overall performance. The optimal boat speed for this vessel was determined at true wind speeds (TWS) of 4, 8, 12, 16, and 20 knots, using both the jib (up to 120° TWA) and the spinnaker (from 80° TWA). The optimized speed of the yacht was found to be comparable to that of international similar-class yachts.