Fig.14 |
Comparisons of turning trajectories of 35°rudder angle, observed and predicted
ship mark: observed by free-running tests
dotted bold line: prediction by the proposed hydrodynamic coefficients
dotted thin line: prediction by the originally measured coefficients |
(Ship model A)
(Ship model C)
(Ship model D)
(Ship model F)
In each figures, dotted bold lines represent the simulated results using the estimated derivatives and coefficients, and dotted thin lines using the measured original data in references. Fig.13 shows the comparisons of simulated spiral characteristics compared with the measured ship motions, and Fig.14 shows the comparisons of turning trajectories of 35° rudder angle. These simulated results that are using the proposed formulas of hydrodynamic coefficients are well coincident with measured ship motions for the wide range of ship dimensions. As the results, the manoeuvring prediction method proposed here becomes a practical tool for the design, research and investigation of fishing vessels, though the size of database is not enough.
6. CONCLUSION
The authors have shown the hydrodynamic derivatives and the other coefficients, and proposed the manoeuvring prediction method for fishing vessels. The concluding remarks are summarized as the followings.
1) Linear hydrodynamic derivatives without trim can be estimated by Kijima's model. However, the Kijima's trim-corrections are not available for fishing vessels. For this correction, eq. (10) proposed here are suitable.
2) Non-linear derivatives can be estimated by the simple formulas as shown in eq. (12) - eq. (14). They can be expressed by dem/B or trim.
3) Interactive force coefficients among hull, propeller and rudder can be estimated by Cb/(L/B) as in eq. (15) and eq. (16).
4) The predicted manoeuvring ship motions that are using the above mentioned formulas of hydrodynamic derivatives and coefficients are well coincident with measured one for a wide range of ship dimensions of fishing vessels.
5) In order to make the prediction much more accurate, hydrodynamic database shall be increased.
The authors would like to express many thanks to Mr. Akihiko Matsuda and Mr. Shiro Suzuki in National Research Institute of Fisheries Engineering, Fisheries Research Agency. They successfully contributed to carrying out the model tests.
REFERENCES
[1] Taguchi, H., Ishida, S., Watanabe, I., Sawada, H., Tsujimoto, K., Yamakoshi, Y, Ma, N. "A Study on Factors Related to the Capsizing Accident of Fishing Vessel "Ryuho Maru No.5" " SNAJ, 190, pp.2l'7-225, 2001, (in Japanese)
[2] Umeda, N., Hashimoto, H. "Qualitative aspects of nonlinear ship motions in following and quartering seas with high forward Velocity", J Mar Sci Technol, 6, pp.111-121, 2002
[3] Ogawa, A., Kasai, H. "On the Mathematical Model of Manoeuvring Motion of Ship", ISP, 25, 292, pp.306-319, 1978
[4] Kose, K., Yumuro, A. and Yoshimura, Y. "Concrete of Mathematical model for ship manoeuvrability", 3rd S. on ship manoeuvrability, SNAJ, pp.27-80, 1981, (in Japanese)
[5] Yoshimura, Y., Ma, N., Suzuki, S., Kajiwara, Y. "Manoeuvring Performance of the Fishing Boat Modified by a Bulge" SNAJ, 192, pp.37-46, 2002 (in Japanese)
[6] Kijima, K., Tanaka, S., Furukawa, Y, Hori, T. "On a prediction method of ship manoeuvring characteristics. Proc. of MARSIM'93S, pp.285-294, 1993
[7] Yoshimura, Y. "Discussion on the prediction of ship manoeuvrability with a Flapped Rudder" 21st ITTC, 2, pp.89-91, 1996
AUTHOR'S BIOGRAPHY
Prof. Yasuo Yoshimura:
He was born in Japan in 1950. He graduated from Hiroshima University in 1973, and continued studying in naval architect and took a Master's degree of marine engineering in 1975. He got a Ph.D. in marine engineering from Osaka University in 1978. After graduating the university, he employed by Sumitomo Heavy Industries, Ltd and working as a senior researcher in Fluid-Dynamics Engineering Section of R & D center of the company. In 2000, he moved to graduate school of fisheries sciences Hokkaido University. He is working as the professor of Production System Control for Fisheries.
Dr. Ning Ma:
He was born in China in 1961. He graduated from Yokohama National University in 1984, and continued studying in NAOE (naval architecture and ocean engineering) and took a Master's degree of engineering in 1986. He got a Ph.D. in NAOE from the same university in 1989. He had been working in Yokohama National University as an associate professor of NAOE from 1993 to 2000. In 2000, he moved to National Research Institute of Fisheries Engineering and now he is engaging in research stability and seakeeping performance of fishing vessel.
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