The influence of the inclination of the sides of a ship on her motion in a seaway¹²

Article type: Research Article

Authors: Radosavljević, Lj.B.

Affiliations: Faculty of Mechanical Engineering, Belgrade University, Yugoslavia

Note: [1] This paper has been presented by the author on the 4th of June 1956 at the III Yugoslave Congress of applied Mechanics in Bled, and on the 5th of September 1956 at the IX International Congress of applied Mechanics in Brussels.

Note: [2] In this paper are given the definition of the problem, the assumption upon which it has been considered, a summary of the solution to the problem, as well as a summary of the results obtained and the conclusions. Two appendices have been deleted. These represent together with the paper a complete work. In them has been demonstrated the mathematical treatment of the problem which is given in this paper (the deduction of the differential equations of the additional oscillations of a ship, determination of the constants which depend on the geometrical form of the ship and on the length of the waves, and so on). These appendices can be obtained on application to author.

Abstract: The influence of the inclination of a ship’s sides to the vertical in the vicinity of the flotation surface on the motion of the ship in a seaway was discussed by A.N. Kriloff [1], I.G. Boobnov [2] and F. Horn [3]. Their discussions were limited to the calculation of this effect for particular ships only of given dimensions and forms. The author deduces the differential equations of motion for additional oscillations caused by the above mentioned factor in the way shown by I.G. Boobnov [2] and substitutes the real frame lines at the ship’s ends by approximate analytical curves corresponding to the main characteristics and dimensions of the ship. The inclination of these lines varies considerably. The author shows (for the case when the length of the waves λ is equal to that of the ship L): a. that in ships of usual form the influence of the deviation of the sides from the vertical is considerably smaller than that of the Smith Effect, and compared to it can be neglected, and b. that the ratio T/L has a contrary influence on the Smith Effect as compared with the correction due to the deviation of the sides from the vertical.

DOI: 10.3233/ISP-1957-43804

Journal: International Shipbuilding Progress, vol. 4, no. 38, pp. 542-550, 1957