International Shipbuilding Progress - Volume 22, issue 254

Authors: Vermeer, H.

Article Type: Research Article

Abstract: The main theme of this paper is to outline a mathematical evaluation of the motions of the ship and the tensile force in the warp, upon the occasion a beamtrawl becomes suddenly ‘fastened’ in an abrupt manner on an obstruction on the seabed e.g. a wreck during the operation of trawling. In addition to the linearization of the problem the many approximations and assumptions made in this study will be outlined or considered. This analysis has revealed a number of preliminary conclusions relating to ships stability and the strength of gear, which could well be of importance for …both regulatory and design purposes. Show more

DOI: 10.3233/ISP-1975-2225401

Citation: International Shipbuilding Progress, vol. 22, no. 254, pp. 331-339, 1975

Authors: Flower, J.O. | Towhidi, A.

Article Type: Research Article

Abstract: The maximum likelihood method of identification of parameters of dynamic processes was introduced in 1965 and has been used for numerical identification of a selection of industrial processes since that time. As the authors know of only one other attempt to apply this technique in the shipping world, this report presents the background theory of the method before describing its application to investigate the rolling and steering characteristics of a 2300 ton displacement vessel. Although these results do not lead to definitive conclusions, they reveal the potential of the method in an area in which easily applicable techniques are sparse. …The biggest advantage of this technique is that it is reasonably undemanding on ship’s time and, in fact, may be applied without seriously interfering with the normal operation of the vessel. Show more

DOI: 10.3233/ISP-1975-2225402

Citation: International Shipbuilding Progress, vol. 22, no. 254, pp. 340-348, 1975

Authors: El Gammal, M.M.

Article Type: Research Article

Abstract: None of the damage concepts in current use for estimating the fatigue life of a ship takes into consideration the complete history of the stress spectrum of that ship. The work presented in this paper is an attempt to establish a method that takes into consideration the whole spectrum in the estimation of the fatigue life of a ship. Discussions of the effects of corrosion allowances, stress concentrations, the ratio of hogging to sagging as well as the effect of load variation between ballast and full load conditions are also presented. The method is applied to predict the fatigue …life in a number of practical cases. Show more

DOI: 10.3233/ISP-1975-2225403

Citation: International Shipbuilding Progress, vol. 22, no. 254, pp. 349-363, 1975