REDUCING THE VERTICAL MOTION IN WAVES OF ROUND-BILGE BOAT WITH CONTROLLABLE TRANSOM FLAPS

Article type: Research Article

Authors: Lin, Wu-Qiang | Dong, Zhu-Shun

Affiliations: Beijing Aviation & Astronautics University, Engineer of Navy Research Center, China | Professor of Naval Academy of Engineering, China

Abstract: A controllable transom flap on round-bilge boat not only may reduce the resistance at cruising speeds in still water, but also could be designed to make a boat run at or near optimum attitude in various environmental condition which results in a motion reduction in waves. The study is to design a suitable automatic system of controllable flaps to reduce the motion of round-bilge boats in irregular waves. In this paper, considering the controllable flap as an exciting force and moment, the motion equation of round-bilge boats with controllable flaps have been based on a modified strip theory. The purpose is to improve the feasibility and effectiveness of the controllable flap as a means of pitch- reducing. Model tests make use of an oscillating flap instead of a controllable flap for checking up the effects of pitch- reduction of flaps. Model tests carried out in the ship model towing tank of Huazhong Science & Technology University have shown that using an oscillating flap would reduce pitching motion effectively, if a suitable phase could be established between flap exciting forces and wave disturbances.

Journal: International Shipbuilding Progress, vol. 49, no. 1, pp. 37-51, 2002