The effect of forebody section shape on ship behaviour in waves¹²

Article type: Research Article

Authors: Swaan, W.A. | Vossers, G.

Affiliations: N.S.M.B. at Wageningen

Note: [1] Publication No. 192 of the Netherlands Ship Model Basin.

Note: [2] Paper presented at the Spring Meeting of the Royal Institution of Naval Architects, London, March 1961.

Abstract: Experiments have been carried out with a series of six models. These models had the same principal dimensions and displacement, but differed in section shape in the forebody and in prismatic coefficient. Results are presented from tests in head seas and in bow seas. Measurements have been made of pitch, heave, motion of the bow relative to the waves, thrust increase, and midship wave bending moments. It is concluded that U-shaped sections are advantageous as regards wetness, speed loss, bending moments and even as regards slamming on some occasions. V-shaped sections are advantageous as regards motions, especially in waves longer than the ship (i.e. for small ships). Furthermore, it is found from the experiments that decreasing the midship coefficient is unfavourable in regard to wetness and the tendency to slamming. To reduce speed loss a low midship area coefficient is to be preferred for fast vessels and a large value for slower ships. Experiments with a model having extreme flare above water in the forebody showed only a small influence on the motions. The extreme flare, however, made the model much more susceptible to slamming.

DOI: 10.3233/ISP-1961-88301

Journal: International Shipbuilding Progress, vol. 8, no. 83, pp. 279-301, 1961