エビ漕網の基礎的研究-II
エビ漕網の海上実験
1974 年 40 巻 10 号 p. 993-997
詳細
1974 年 40 巻 10 号 p. 993-997
Field experiments were carried out uslng a polyethylene shrimp drag in order to make clear the differences in the towing resistance between the gear with a cover-net for mesh selection and one without the covernet. The experiments were conducted in the waters with a muddy bottom under calm sea conditions. We measured the warp tension at its foremost end in relation to the towing speed under drag trawling condition and also when keeping the gear in the layer dose to the surface. The results indicate that in the ease of the gear with the cover-net the towing resistance increased by about 20% in comparing with the resistance when the cover-net was detached from the gear, and also the frictional resistance amounted to about 35% of the whole towing resistance.
