Method of predicting course stability and turning qualities of ships¹

Article type: Research Article

Authors: Jacobs, Winnifred R.

Affiliations: Davidson Laboratory, Stevens Institute of Technology, Hoboken, N.J.

Note: [1] This study was carried out at Davidson Laboratory, Stevens Institute of Technology, Hoboken N4 under sponsorship of the Office of Naval Research Contract Nonr 263(40) Technically administered by David Taylor Model Basin.

Abstract: An analytical method combining simplified potential flow theory and low aspect-ratio wing theory with empirical modifications for a real viscous fluid is used to predict the stability derivatives (first order hydrodynamic force and moment derivatives) of a family of hulls in order to estimate the dependence on geometric characteristics of course stability and turning or steering qualities. The hulls are Taylor Standard Series forms with after deadwood removed and have the same length and prismatic coefficient but varying length-draft and beam-draft ratios and skeg area. Comparison between the values calculated by this method and those obtained from experimental measurements shows good agreement. The analytical method can predict the relative effects of the geometrical characteristics Calculated magnitudes are slightly different from the experimental but are on the conservative side. However, since the hulls tested have the same prismatic, the empirical modification for the rotary moment derivative which is a function of prismatic coefficient has not been fully tested. Necessary refinements of the method must wait on analysis of data on series of forms with different prismatic as well as length-draft and beam-draft ratios.

DOI: 10.3233/ISP-1964-1112102

Journal: International Shipbuilding Progress, vol. 11, no. 121, pp. 414-425, 1964