• Title/Summary/Keyword: Hard Chine

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Calculation of Added Mass and Added Moment of Inertia for Chine Hull by Strip Method (단일배골형선(單一背骨型船)의 부가질량(附加質量) 및 부가관성(附加慣性)모우멘트의 일계산(一計算))

  • J.H.,Hwang;K.J.,Cho
    • Bulletin of the Society of Naval Architects of Korea
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    • v.5 no.2
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    • pp.45-50
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    • 1968
  • The added mass and the added moment of inertia of a hard chine hull for heave and pitch were calculated by strip method. For the $k_2$ coefficients, Hwang's values for the straight-framed sections were used and for $k_2$ coefficients Porter's values for ellipses were used in the calculation. Comparisons on added mass and added moment of inertia of hard chine hull with those of ordinary hull form were briefly discussed. The results of the calculation for hard Chine hull give greater valves than ordinary ships at zero Froude Number. Beam draft ratio seems to be much influenced on the added mass and added moment of inertia.

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The Transverse Dynamic Stability of Hard-chine Planing Craft

  • Lewandowski, Edward-M.
    • Journal of Ship and Ocean Technology
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    • v.2 no.1
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    • pp.1-12
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    • 1998
  • A method to predict the dynamic roll stability of hard-chine planing craft is presented. Starting with the equation of motion, an equation governing small roll perturbations is developed. The roll restoring moment acting on the hull is evaluated by considering “static”and dynamic contributions. The contribution of rudders and skegs, which is significant for this type of craft, is also determined. A worked example is presented to show how the method can be used to find the maximum center of gravity height for transverse stability.

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An Experimental Study on the Section Shape of Medium Size Fishing Boat (중형어선의 단면형상에 관한 실험적 연구)

  • Lee, K.J.;Kim, J.N.;Lee, K.I.
    • Journal of the Society of Naval Architects of Korea
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    • v.34 no.1
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    • pp.87-92
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    • 1997
  • This study was carried out to develop the initial hull form for G/T 89ton class fishing boat cooperatively with Korean Fishing Boat Association. 1be resistance performance of two basic hull forms of hard chine type and displacement type are compared experimentally.

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A Study on the Resistance Property of Hard Chine Type High Speed Planing Craft (HARD CHINE형 활주 고속선의 저항특성에 관한 고찰)

  • 이창억
    • Journal of the Korean Professional Engineers Association
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    • v.16 no.2
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    • pp.1-11
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    • 1983
  • The resistance property of a high speed passenger craft (: "DOL-PIN HO" designed by the author in 1972) is investigated as follows; -. The Resistance property of the craft is determined by savitsky′s method and blount-Fox′s method. The theoretical results are also compared with the full scale data. The comparison reveals that the result when using blount/fox′s method are in much closer agreement with the full scale data than savitsky′s. -. The effects of ship speed on the positions of the center of pressure and of the longitudinal center of gravity (L.C.G.) are investigated. The investigation shows that the position of L.C.G. of the craft is almost constant although the ship speed is changed. -. The effect of transom flap on the Resistance property of the craft is studied using savitsky/brown′s method. From the study it is found that the resistance of the craft is decreased and hence speed gain (about 3% of the service speed) can be obtained, when using transom flap for the craft.

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Comparison of Hydrodynamic Performance between the Existing and Esthetic Form for the Fishing Boat

  • Lee, Kwi-Joo;Joa, Soon-Won;Park, Na-Ra;Sarath, E.S.
    • Proceedings of the Korea Committee for Ocean Resources and Engineering Conference
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    • 2003.10a
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    • pp.177-181
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    • 2003
  • Despite various forms have been developed and applied to ship hull forms, the superiority of hard chine type over other forms of fishing boat has been recognized so far. As one of the ways of forms for new concept fishing boat, this paper presents the result of a performance evaluation for newly developed forms of hull, appendage and deck house, which features that have esthetic forms.

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Bubble Wake Measurement by Acoustic Bubble Spectrometer Generated by Planing Hull at Circulating Water Channel (회류수조에서의 ABS에 의한 활주선 후류 기포항적계측)

  • Shin, Myung-Soo;Moon, Il-Sung;Nah, Young-In;Park, Jong-Chun
    • Journal of the Korea Institute of Military Science and Technology
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    • v.14 no.1
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    • pp.55-61
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    • 2011
  • This paper presents bubble wake measurement results generated by the planing hull. The bubble was generated by SNAME TMB model(No. 4876) with hard chine at the CWC(Circulating Water Channel). ABS(Acoustic Bubble Spectrometer) was used to measure bubble wake measurement. The manufactured model is one meter in length and uniform velocity to generate the bubble at CWC is 3m/s, relatively higher speed than conventional hull form. Measurements were performed successfully and measured results show well the general characteristics of bubble wake generated by planing hull. Furthermore, experimental equations are proposed for the practical use.

Application of Semi-Twin Hull Form to a Medium Size Off-Shore Long Liner (반쌍동선미선형을 갖는 중형연승어선의 저항성능에 관한 연구)

  • Lee, Kwi-Joo;Han, Jae-Ho
    • Journal of the Korean Society of Fisheries and Ocean Technology
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    • v.33 no.4
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    • pp.259-265
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    • 1997
  • The new concept of hull form for G/T 19 ton class off-shore long liner was studied with the support of special research fund of Korean Ministry of Science and Technology. Newly developed hull form of semi-twin afterbody combined with part. curvilinear type forebody shows outstanding improvement in resistance performance point of view compared with hard chine form, especially at the range of high speed.

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Sensory Evaluation of Fabric Touch by Free Modulus Magnitude Estimation

  • Cho, Gilsoo;Kim, Chunjeong;Casali, John G.
    • Fibers and Polymers
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    • v.3 no.4
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    • pp.169-173
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    • 2002
  • Fabric touch was evaluated psychophysically in order to determine the relationship between mechanical properties and subjective sensation. For subjective touch sensation, eight aspects such as hardness, smoothness, coarseness, coolness, pliability, crispness, heaviness and thickness were evaluated using free modulus magnitude estimation (FEME) technique. KES-FB was used to measure the mechanical properties of fabrics. Woolen fabric with the highest values of WC and weight was evaluated as the coarsest, heaviest and thickest. While silk crepe do chine with the lowest LT, G, 2HG, thickness and weight was rated as smoother and more pliable than any other fabrics. And flax with the highest values of LT and SMD was evaluated as hard, cool and crisp. Fabric touch and satisfaction were predicted well from the mechanical properties, especially from SMD, by regression analysis. Satisfaction for touch increased as smoothness increased.

A Numerical Study on Dynamic Instability Motion Control of Wave-Piercing High-Speed Planing Craft in Calm Water using Side Appendages

  • Kim, Sang-Won;Seo, Kwang-Cheol;Lee, Dong-Kun;Lee, Gyeong-Woo
    • Journal of the Korean Society of Marine Environment & Safety
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    • v.23 no.3
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    • pp.320-329
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    • 2017
  • In this research, we have calculated characteristics of wave-piercing high-speed planing hull, by using a RANS solver and overset grid method, for comparing with experimental measurements of that and simulating with several appendages, since the computed results of commercial CFD code look reasonable for the prediction of the performances of planing hulls on calm water in planing conditions. As a result, it is confirmed that the dynamic instability phenomena in pitch and heave motions (porpoising) occurred after a certain $Fn_V$, and effectively suppressed using some of appendages, especially the 0.5L spray rail is suppressed to 24-55 % in the pitch motion and 33-55 % in the heave motion. In spray phenomenon, 1L hard chine suppress spray effectively and it is effective to set the angle of appendages to be less than $0^{\circ}$ in order to suppress wave.