著者

雨宮 伊作 大杉 勇

出版者

公益社団法人 日本航海学会

雑誌

日本航海学会論文集 (ISSN:03887405)

巻号頁・発行日

vol.79, pp.141-149, 1988-09-25 (Released:2017-01-15)

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The NIPPON MARU, 2570 ton 4-masted bark, was built in 1984 to replace former NIPPON MARU as a sail training ship for the cadets of Institute for Sea Training, Ministry of Transport, Japan. The authors have carried out the experiments to measure her sailing speed, leeway, apparent wind direction and speed and others in trade-wind zone of the North Pacific Ocean. In analyzing these experimental data, we have got ship speed/true wind speed ratio for each trim angle of yards and sail condition. Secondly, we have got aerodynamic coefficients of her sails, by solving the equilibrium equations in steady sailing conditions. The results are as follows. In respect of ship maneuvering, she made a speed of more than 75% of true wind speed in close-hauled under fullsails, when her propellers were revolving freely. Stays'ls were effective when she sailed in the range from close-hauled to beam reach condition. In following wind condition she made a speed of 20% of the true wind speed under fore and aft sails only. In respect of aerodynamic performance, her sails stalled at 25 degrees of the attack angle and had a considerably larger lift and drag forces than those by wind tunnel test. Her thrust force coefficient was maximum at close-reaching because of no interference of the aft sails to the fore sails, and thrust force mainly depended on her sail area.