• Title/Summary/Keyword: High speed craft

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Comparative Study on the Motion Responses for a 40ft Class Cruise Leisure Boat (40ft 급 크루즈 레저보트의 운동성능 해석 및 모형시험 비교 연구)

  • Kim, Dong-Jin;Rhee, Key-Pyo;Yum, Deuk-Joon;Zhang, Yang
    • 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.

A Study on the Effects of Weight and Center of Gravity of a Planing Craft on Running Attitude (활주선의 하중 및 무게 중심 위치 변화가 항주 자세에 미치는 영향에 대한 연구)

  • Kim, Dong-Jin;Rhee, Key-Pyo;Park, Han-Sol
    • Journal of the Society of Naval Architects of Korea
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    • v.46 no.3
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    • pp.335-342
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    • 2009
  • Motion characteristics of a planing craft are sensitively changed according to its weight and longitudinal center of gravity. In this paper, planing craft model tests were performed in calm water for various test conditions and Froude numbers. Sinkage and trim were measured to analyze the relations between the attitudes of a planing craft and the weight and center of gravity of it. Theoretical formula for the prediction of the attitudes of a prismatic planing hull was modified so that it can be applied to the prediction of the attitudes of a non-prismatic planing hull, and the calculation results by the modified formula were in good agreements with the experimental data.

A Study on Conceptual Structural Design of Wing for a Small Scale WIG Craft Using Carbon/Epoxy and Foam Sandwich Composite Structure

  • Kong, Chang-Duk;Park, Hyun-Bum;Kang, Kuk-Gin
    • Advanced Composite Materials
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    • v.17 no.4
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    • pp.343-358
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    • 2008
  • This present study provides the structural design and analysis of main wing, horizontal tail and control surface of a small scale WIG (Wing-in-Ground Effect) craft which has been developed as a future high speed maritime transportation system of Korea. Weight saving as well as structural stability could be achieved by using the skin.spar.foam sandwich and carbon/epoxy composite material. Through sequential design modifications and numerical structural analysis using commercial FEM code PATRAN/NASTRAN, the final design structural features to meet the final design goal such as the system target weight, structural safety and stability were obtained. In addition, joint structures such as insert bolts for joining the wing with the fuselage and lugs for joining the control surface to the wing were designed by considering easy assembling as well as more than 20 years service life.

A study on the development of resistance and pitching improving device for high speed fishing vessel (고속어선의 저항 및 핏칭 개선장치 개발에 관한 연구)

  • 이귀주;오훈택
    • Journal of Ocean Engineering and Technology
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    • v.11 no.3
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    • pp.89-94
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    • 1997
  • In the design of high speed fishing vessel, its hull form has to be decided from a view point of resistance and propulsion performance without negelction of seakeeping characteristics. In spite of many efforts, the performance improvement by hull form itself has its limitations, specially for high speed craft. In this paper, the development of performance of resistance and seakeeping improving appendage for high speed planing hull on behalft of the hull form of fishing vessel has been introduced. The developed appendage verified its effectiveness in the full scale test.

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Study on the Design of Shaft Strut for Naval Ships with Twin Screw (2축 함정의 스트럿 설계에 관한 고찰)

  • 박명규;신영균
    • Journal of the Korean Society of Marine Environment & Safety
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    • v.8 no.1
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    • pp.81-87
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    • 2002
  • High speed naval ships are configured with open shafts The shafts, bearings, and propellers are supported by shaft struts. Proper design of struts involves issues of structural, vibration, and hydrodynamic analysis and design. Strut arm cavitation in high speed occurs because of a misalignment of the strut arm with the local incident flow. Proper selection of the strut section can minimize the generation of cavitation. This paper describes issues in the design struts and notices based on the design of Patrol Craft and Amphibious Ship.

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A comparison study on the deck house shape of high speed planing crafts for air resistance reduction

  • Park, Chung-Hwan;Park, Hee-Seung;Jang, Ho-Yun;Im, Namkyun
    • International Journal of Naval Architecture and Ocean Engineering
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    • v.6 no.4
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    • pp.867-875
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    • 2014
  • Planing crafts were specifically designed to achieve relatively high speeds on the water. When a planing craft is running at high speed, dynamic pressure on the bottom makes the boat rise on the surface of the water. This reduces the area of the sinking surface of the boat to increase air resistance. Air resistance means the resistance that occurs when the hull and deck house over the surface of the water come in contact with the air current. In this paper, we carried out a CFD numerical analysis to find optimal deck houses that decreased air-resistance on the water when planing crafts are running at high speed. We finally developed the deck house shape of high-speed planing crafts that optimally decreased air resistance.

A feasibility study on the improvement of performance for high speed fishing vessel (부가물에 의한 고속어선의 성능개선 가능성에 관한 연구)

  • 이귀주;박원미
    • Journal of the Korean Society of Fisheries and Ocean Technology
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    • v.38 no.4
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    • pp.289-292
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    • 2002
  • In the design of high speed fishing vessel, it's hull form has to be decided from a view point of resistance and propulsion performance without neglection of seakeeping characteristics. In spite of many efforts, the performance improvement by hull form itself has it's limitations, specially for high speed craft. In this paper, a study on the improvement of performance for high speed planing hull type fishing vessel has been introduced.

Eco-friendly selection of ship emissions reduction strategies with emphasis on SOx and NOx emissions

  • Seddiek, Ibrahim S.;Elgohary, Mohamed M.
    • International Journal of Naval Architecture and Ocean Engineering
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    • v.6 no.3
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    • pp.737-748
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    • 2014
  • Increasing amounts of ships exhaust gases emitted worldwide forced the International Maritime Organization to issue some restricted maritime legislation for reducing the adverse environmental impacts arising from such emissions. Consequently, ships emission reduction became one of the technical and economical challenges that facing the ships, operators. The present paper addresses the different strategies that can be used to reduce those emissions, especially nitrogen oxides and sulfur oxides. The strategies included: applying reduction technologies onboard, using of alternative fuels, and follows one of fuel saving strategies. Using of selective catalytic reduction and sea water scrubbing appeared as the best reduction technologies onboard ships. Moreover, among the various proposed alternative fuels, natural gas, in its liquid state; has the priority to be used instead of conventional fuels. Applying one of those strategies is the matter of ship type and working area. As a numerical example, the proposed methods were investigated at a high-speed craft operating in the Red Sea area between Egypt and the Kingdom of Saudi Arabia. The results obtained are very satisfactory from the point of view of environment and economic issues, and reflected the importance of applying those strategies.