International Shipbuilding Progress - Volume 23, issue 263

Authors: Flower, J.O.

Article Type: Research Article

Abstract: A perturbational process is applied to the non-linear rolling of a ship in a sea described by the power spectral density of its waveslope; this produces a formula which is simple to apply. The results indicate that the roll power spectral density is “harder” than that predicted from linear theory which appears to be in keeping with measured data previously published.

DOI: 10.3233/ISP-1976-2326301

Citation: International Shipbuilding Progress, vol. 23, no. 263, pp. 209-212, 1976

Authors: Shaher Sabit, A.

Article Type: Research Article

Abstract: Graphical and analytical methods have been previously provided for the hull surface generation and calculation of the main geometric particulars of the SSPA cargo liner series [1,2]1 1 Numbers in brackets refer to References listed at the end of this paper. . Graphical methods have been presented by the SSPA for the calculation of the resistance and propulsive coefficients of any series form [3,4]. However, certain simplified assumptions were used, the analysis involved extrapolation beyond the limits of the series and corrections due to deviations from the standard LCB position were not given. Numbers in brackets refer …to References listed at the end of this paper. This paper presents the results of the regression analyses performed on the resistance and propulsive coefficients data of the SSPA cargo liner series, which aimed at developing analytical expressions not involving unvalid assumptions and provide the necessary corrections to account for variations in the LCB position from the standard adopted. These regression equations are subsequently used to form a computer program for the calculation of the resistance and propulsive coefficients of any intermediate form within the range of the series, and are compatible with the generated hull forms provided from earlier analysis. Show more

DOI: 10.3233/ISP-1976-2326302

Citation: International Shipbuilding Progress, vol. 23, no. 263, pp. 213-217, 1976

Authors: Oosterveld, M.W.C. | van den Berg, W.

Article Type: Research Article

Abstract: The improvement in performance which can be obtained by application of ducted propellers on bulk carriers and tankers depends very much on, the afterbody-nozzle configuration. Investigations carried out so far on these applications are mostly restricted to isolated cases. In this paper, based on systematic tests performed in the Depressurized Towing Tank of the Netherlands Ship Model Basin, information is given about the influence of nozzle length, nozzle shape, propeller diameter, hull-nozzle clearance and about the influence of adaptation of the nozzle to the wake flow on the performance of large ships.

DOI: 10.3233/ISP-1976-2326303

Citation: International Shipbuilding Progress, vol. 23, no. 263, pp. 218-231, 1976

Authors: Cummings, D.E.

Article Type: Research Article

Abstract: A great deal of effort has been devoted in recent years to study of the deformation of the wake from propeller blades. Relationships between loading, vortex rollup, contraction, and pitch variation have been studied. This paper discusses analytical and experimental developments, and emphasizes the effects on design and performance of high speed high thrust subcavitating propellers.

DOI: 10.3233/ISP-1976-2326304

Citation: International Shipbuilding Progress, vol. 23, no. 263, pp. 232-241, 1976