International Shipbuilding Progress - Volume 29, issue 333

Authors: Yamamoto, Y. | Fukasawa, T. | Arai, M. | Kajita, E.

Article Type: Research Article

Abstract: A number of ship disasters took place in succession during the past several years in the North Pacific Ocean, and investigations of ship’s responses among high waves have been done in order to clarify the mechanism of the disasters. The first two authors of the present paper and Fujino proposed a theory for determining behaviors of a ship among rough seas, taking account of impact forces due to slamming, and the special version of the theory can be used for determining rigid-body motions. Series of experiments are conducted with a model for a fast container ship of fine hull …form with prominent bow-flare; the results obtained are in good accordance with the nonlinear theory even in case of slamming. Show more

DOI: 10.3233/ISP-1982-2933301

Citation: International Shipbuilding Progress, vol. 29, no. 333, pp. 118-124, 1982

Authors: Pawlowski, J.S.

Article Type: Research Article

Abstract: The present paper presents an attempt to deal with the problem of applying analytic models of reality in decision making processes. The problem is not unknown to ship designers and research naval architects as it is their common experience that developed algorithms such as those for ship motions are employed in ship design process for checking performance after the relevant design particulars have already been decided. In the opinion of the author the knowledge embodied in such algorithms should and can be effectively applied in the essential design process of choosing the appropriate particulars. In the paper the obstacles …hindering such a use are identified by recognising the decision making process of design. The algorithms are included in a class of scientific models for which the name of structural models is used in the paper and an analysis of those models is carried out which shows their inherent inability to suit a design process. The solution to the problem is found in the identification of models specially adapted to the needs of the decision maker, for which the name of nonstructural models is employed. The process of identification of such models is discussed in general and an example of application of such a model in seakeeping is presented, which quantifies the influence of the relevant underwater ship form parameters upon the variance of relative bow motion in head waves. It is found that of those parameters waterplane area coefficient is the one of dominating importance for its effect on relative bow motion. Show more

DOI: 10.3233/ISP-1982-2933302

Citation: International Shipbuilding Progress, vol. 29, no. 333, pp. 125-135, 1982

Authors: Haddara, M.R.

Article Type: Research Article

Abstract: The coupled nonlinear pitch-roll motions in random waves are studied using deterministic and stochastic averaging techniques. The stability of the stationary solution is analysed and stability criteria are obtained. Moreover, the statistical properties of the stationary solution are obtained.

DOI: 10.3233/ISP-1982-2933303

Citation: International Shipbuilding Progress, vol. 29, no. 333, pp. 136-139, 1982