• Title/Summary/Keyword: High speed craft

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Thermo-economic approach for absorption air condition onboard high-speed crafts

  • Seddiek, Ibrahim S.;Mosleh, Mosaad;Banawan, Adel A.
    • International Journal of Naval Architecture and Ocean Engineering
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    • v.4 no.4
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    • pp.460-476
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    • 2012
  • High-speed crafts suffer from losing a huge amount of their machinery energy in the form of heat loss with the exhaust gases. This will surely increase the annual operating cost of this type of ships and an adverse effect on the environment. This paper introduces a suggestion that may contribute to overcoming such problems. It presents the possibility of reusing the energy lost by the ships' exhaust gases as heating source for an absorption air condition unit onboard high-speed crafts. As a numerical example; the proposed method was investigated at a high-speed craft operating in Red Sea between Egypt and the Kingdom of Saudi Arabia. The results obtained are very satisfactory. It showed the possibility of providing the required ship's air condition cooling load during sailing and in port. Economically, this will reduce the annual ship's operating cost. Moreover, it will achieve a valuable reduction of ship's emissions.

Numerical Prediction of Running Attitude and Resistance of Planing Craft (수치계산에 의한 활주선의 항주 자세 및 저항 추정)

  • Oh, Gwangho;Yoo, Jaehoon
    • Journal of the Society of Naval Architects of Korea
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    • v.50 no.2
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    • pp.95-103
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    • 2013
  • Prediction of the running posture is important to evaluate the resistance by the numerical calculation for a high speed vessel. Especially for a planing craft having a large variation of running attitude it becomes more essential, but it can not be obtained easily because the running posture and the hydrodynamic forces including the resistance are interacted with each other. So iterative calculation to obtain the dynamic forces according to the changes in attitude is necessary, in this study, considering the calculated hydrodynamic force at the assumed draft as the additional buoyancy the corrected draft is calculated through satisfying the equilibrium between the buoyancy and the hull weight. To verify the derived method three kinds of hull forms were used with the results of model tests, R/V ATHENA and 150 tons class guide vessel for middle-speed semi-planing crafts, 28 feet fast boat for a high-speed planing boat. For all cases with several iterations the converged value of draft can be obtained, lastly the resistance and flow around hull were simulated by using VOF method.

Hydrodynamic Forces Acting on Porpoising Craft at High-Speed

  • Katayama, Toru;Ikeda, Yoshiho
    • Journal of Ship and Ocean Technology
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    • v.3 no.2
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    • pp.17-26
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    • 1999
  • An experimental investigation on hydrodynamic forces acting on a porpoising craft at high advanced speeds up to Froude numbers Fn=6.0(Fn=U\ulcorner:Lo\ulcorner denote overall length of ship) in calm water is performed. Captive model tests and forced motion tests are carried out to measure the hydrodynamic forces. The results show that significant nonlinear effects for motion amplitudes appear in the restoring, the added mass and the damping coefficients. The experimental results are compared with the results of a prediction method of the hydrodynamic forces include the nonlinear effects, and show a good agreement with them. A simulation using the predicted hydrodynamic forces in a nonlinear motion equation is carried out to obtain the porpoising motion of a craft in calm water. The calculated results are in fairly good agreement with experimental ones.

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Study on Preliminary Structural Design of Light Weight Small Scale WIG Craft (경량화 소형 위그선 구조 예비 설계에 관한 연구)

  • Kong, Changduk;Park, Hyunbum;Kim, Juil;Lee, Seunghyeon;Yun, Jae-Hwi
    • Journal of Aerospace System Engineering
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    • v.1 no.1
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    • pp.36-44
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    • 2007
  • This study was performed on preliminary structural design of a small scale WIG craft which has been developed as a next generation high speed maritime transportation system in Korea. A composite structure design using the foam-sandwich for main wing and tail fins and the honeycomb sandwich and skin-stringer-ring frame for fuselage was applied for weight reduction as well as structural stability. A commercial FEM code, NASTRAN for was utilized to confirm the structural safety for the reiterate design modifications to meet design requirements including the target weight. Each main wing was jointed with the fuselage by eight high strength insert bolts for easy assembling and disassembling as well as for assuring the required 20 years service life. For control surface structural design, the channel type spar, the foam sandwich skin and the lug joint were adopted.

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On the impact hydrodynamic load on the bottom of high-speed small craft (고속정(高速艇)의 선저(船底)에 작용(作用)하는 충격하중(衝擊荷重)의 추정(推定))

  • S.J.,Yim;J.G.,Shin
    • Bulletin of the Society of Naval Architects of Korea
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    • v.15 no.3
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    • pp.1-7
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    • 1978
  • The dynamic pressures on the bottom of high speed small crafts are studied. Using the dynamic load factor the dynamic pressure can be replaced by equivalent static pressure. Assuming that (1) the system is undamped with a single degree of freedom and (2) the load is applied triangularly, we obtained the max, value of the dynamic load factor of 1.455. We believe that this method could provide a guide to the designer who has no data on the craft in the preliminary structural design stage.

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