Shipmotions in longitudinal waves¹

Article type: Research Article

Authors: Gerritsma, J.

Note: [1] Publication no. 14 of the Shipbuilding Laboratory, Technological University, Delft.

Abstract: In this study on shipmotions, three methods are used to determine the frequency response function of a shipmodel in longitudinal waves. In the first place, heaving and pitching motions of three shipmodels of different fullness have been measured in regular waves. The second method is based on the assumption that heave and pitch can be described with sufficient accuracy by a set of two coupled linear differential equations of the second order. The coefficients in these equations have been determined by means of experiments, and the solution of the equations of motion gave the frequency response function of the shipmodel. Here again, three models were used to test the assumptions. The third method is based on the assumption that the response of a shipmodel in irregular waves may be found by a linear superposition of motions in regular waves. Consequently, the frequency response function may be found by analysing the result of tests in irregular waves. This has been done for one shipmodel only. The results of the three methods are compared. For the sake of completeness some of the results of earlier work are also given in this publication.

DOI: 10.3233/ISP-1960-76601

Journal: International Shipbuilding Progress, vol. 7, no. 66, pp. 49-71, 1960