The Experiments on the Sailing Performance of the Sail Training Ship Nippon Maru
| Autor: | Isamu Ohsugi, Isaku Amemiya |
|---|---|
| Rok vydání: | 1988 |
| Předmět: | |
| Zdroj: | The Journal of Japan Institute of Navigation. 79:141-149 |
| ISSN: | 2187-3275 0388-7405 |
| DOI: | 10.9749/jin.79.141 |
| Popis: | The NIPPON MARU, 2650 ton 4-masted bark, was built in 1984 to replace the 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 analysing this experimental data, they obtained ship speed/true wind speed ratios for each trim angle of yards and sail condition. Secondly, they obtained aerodynamic coefficients of her sails, by solving the equilibrium equations in steady sailing conditions. The results are as follows. In respect of ship manoeuvring, she made a speed of more than 75% of true wind speed in close-hauled under full sail, when her propellers were revolving freely. Staysails 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 25Deg. of the attack angle and had a considerably larger lift and drag force 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. |
| Databáze: | OpenAIRE |
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