Field Experiment on Dynamics of Floating Reef" Nirai" Moored in Deep Sea South of Okinawa
九州大学大学院総合理工学研究所 小寺山 亘、 中村 昌彦、 山口 悟、 水岡 浩雄
Interdisciplinary Graduate School of Engineering Sciences, Kyushu University Wataru Koterayama, Masahiko Nakamura, Satoru Yamaguchi and Hiroo Mizuoka
郵政省沖縄電波観測所 増田 悦久、 久木 幸治、 灘井 明嗣
Okinawa branch of Communications Research Laboratory, the Ministry of Posts and Telecommunications Yoshihisa Masuda, Yukiharu Hisaki and Akitsugu Nadai
Offshore Structures & Development Section, Central Technical Office, Kawasaki Heavy Industries, Naoyuki Takatsu and Tooru Fujio
川崎重工業（株） 明石技術研究所 池淵 哲朗
Akashi Technical Institute, Kawasaki Heavy Industries, Tetsuro Ikebuchi
Key Words: Fish-gathering buoy, Deep sea mooring, Field experiment, Dynamics
ABSTRACT
A large floating buoy for fish-gathering has been developed and moored in the deep sea south of Okinawa Island. It is moored in the sea area of 1200 m depth with a composite mooring line of wire rope and chain. The displacement is about 90 ton. To establish a design method for a large buoy system, a series of field experiments were carried out. In these experiments motions of buoy, current velocity, wave height were measured with motion sensors, current meter, HF radar and wave rider buoy. Motions of the buoy obtained from the field experiment are compared with numerical simulations obtained using 3-degree freedom motion equations. The dynamics of the mooring line are calculated with lumped mass technique. Hydrodynamic coefficients of the buoy used in the numerical simulations were obtained from model experiments in a wave tank. The design method for a large buoy system moored in deep sea were confirmed through the field experiments and good effects of the buoy on the fishery were verified by researching the catch around the buoy.
