韓國 近海에 있어서의 中層트로올의 硏究 - Ⅳ - 漁具의 流體抵抗과 展開板의 性能 -

Study on the Midwater Trawl Available in the Korean Waters - Ⅳ - Hydrodynamic Resistance of the Gear and Efficiency of the Otter Board -

The authors carried out an experiment to measure the hydrodynamic resistance of the gear and the efficiency of otter board of the midwater trawl, which is the same used in the former experiment in this series of studies. The whole ressistance of the gear was measured by a 1Oton scale recording tension meter and the resistance of net by a 2ton scale underwater recording tension meter, and they were analyzed into the shearing force and the drag with relevant factors determined in the former experiments. The results obtained can be summarized as follows: 1. The whole drag of gear T(kg) and the drag of net Rn(kg) can be expressed as T=2.15v1.12 Rn=I.96v1.01(v: towing speed in m/sec) 2. The formula of estimating the drag of net deduced by Koyama's method can be expressed as RN=4.3d/ladv 3. The shearing force and the drag of otter board is about 19 to 22% and 5 to 7% of the drag of net, respectively. Whereas, the shearing coefficient and the drag coefficient calculated by the resistance and the opening of gear are 1.5 and 0.42, respectively.