International Shipbuilding Progress - Volume 27, issue 313

Authors: van Oossanen, P.

Article Type: Research Article

Abstract: In preliminary ship design studies it is frequently necessary to estimate the calm water resistance characteristics of various hull forms prior to carrying out model tests. For such estimations, use is generally made of results of well-known methodical model experiments such as Taylor’s Standard Series, Series 60, and others to determine the effect of specific hull form parameters on resistance. For small, high-speed displacement vessels designed to operate in the speed range corresponding to Froude number values of 0.4 to 1.1 (equivalent to a range in V / L of 1.34 to 3.70), these well-known …methodical series results are inadequate due to the limited speed range covered. Alternative methods must then be used. In this paper, all available and reliable data for the prediction of the resistance of small, high-speed vessels, designed to operate in the displacement mode, are presented. Included are the results of restricted and less well-known methodical series and averaged results of tests with a large number of non-systematic models, in both graphical and numerical form. Some basic considerations on how and when each of the presented methods can be applied are also presented. Show more

DOI: 10.3233/ISP-1980-2731301

Citation: International Shipbuilding Progress, vol. 27, no. 313, pp. 212-224, 1980

Authors: Flower, J.O. | Sabti Aljaff, W.A.K.

Article Type: Research Article

Abstract: In this work we obtain approximate analytical solutions of nonlinear differential equations believed to represent, firstly, the decaying oscillations of a rolling ship model and, secondly, the decaying oscillations of a column of water in a surface-piercing tube; this latter problem is relevant to some wave-power producing systems. The method used is due to Kryloff and Bogoliuboff and the forms of the analytical solution obtained are fitted to previously published experimental results with good agreement.

DOI: 10.3233/ISP-1980-2731302

Citation: International Shipbuilding Progress, vol. 27, no. 313, pp. 225-230, 1980

Authors: Ferdinande, V. | Kritis, B.G.

Article Type: Research Article

Abstract: Investigating the hydrodynamic behaviour of floating bodies, for example regarding wave power absorption or the dynamics of offshore structures, one may need the values of added mass and damping coefficients fo a wide parametric variety of geometrical forms. In order to obtain in an economical way and in a short time all needed values for heaving motion of vertical axisymmetric bodies, a case of practical importance, a suitable computation procedure has been developed. The theoretical results have been compared with experimental model data, in order to verify the accuracy of the numerical values obtained. Graphs of these hydrodynamic coefficients for …vertical circular cylinders of various draft-radius ratios, heaving in deep and in shallow water, are given for practical use, as interpolation can be readily done for any other ratio of interest. Show more

DOI: 10.3233/ISP-1980-2731303

Citation: International Shipbuilding Progress, vol. 27, no. 313, pp. 231-240, 1980