Pitch and heave with fixed and controlled bow fins

Article type: Research Article

Authors: Vugts, J.H.^*

Note: [*] Publication no. 30 Delft Shipbuilding Laboratory.

Abstract: A method of calculating the effect of bow antipitching fins on the motions of a model is presented and compared in detail to the results of measurements. The agreement is quite satisfactory, both for the case of fixed and for controlled fins. Next this method is applied to a general cargo ship of the Sixty Series equipped with fixed and with activated fins, respectively. The activated fins are controlled by a nonlinear feedback signal of the pitch velocity. The absolute and relative ship motions in regular and irregular long-crested waves are computed and compared to the motions without fins. The results show a pitch reduction of about one third, while the heaving is not significantly changed. The additional advantage of activated over fixed fins is only slight. Also some particulars of the flow pattern about the fins are established by underwater photographs.

DOI: 10.3233/ISP-1967-1415302

Journal: International Shipbuilding Progress, vol. 14, no. 153, pp. 191-215, 1967