Coursekeeping and broaching of ships in following seas¹

Article type: Research Article

Authors: Wahab, R. | Swaan, W.A.

Affiliations: Netherlands Ship Model Basin, Wageningen, Holland

Note: [1] Publication No. 224 of the Netherlands Ship Model Basin, Wageningen, Holland.

Abstract: This paper containes an investigation of the dynamic stability of ships in following seas. It has been assumed the component of the ship’s velocity in the direction of wave propagation is equal to the wave celerity. The linearized equations of motion of ships in smooth water are used, extended with terms which take into account the exciting forces due to the presence of the waves. These terms are calculated using the Froude-Krylof hypothesis and the assumption that the width and the draft of the ship are small in comparison with the wave length. The ship is assumed to be symmetrical and to have vertical frames at the waterline. Attention is paid to the influence on the maneuverability of heading, wave length, wave height and the application of an autopilot. The linear treatment applied in this paper shows clearly the difficulties connected with navigation in following seas with low frequencies of encounter.

DOI: 10.3233/ISP-1964-1111901

Journal: International Shipbuilding Progress, vol. 11, no. 119, pp. 293-302, 1964