巾着網の網成りと環網に働く張力について

Abstract

In order to find out the most fruitful method for studying the state of the purse seine in operation, the test were made in the water with under-water current on 1/150 and 1/50 scale models by Tauti's principle and the real seine. The results obtained from those experiments are as follows: 1) As shown in Fig. 1 the force acting on the corkline was concentrated chiefly on wings and back (Max; 10kg/m). 2) From the model experiments, the tension of the purse line in operation depends on under-water current. In actual observations the tension was 150kg in setting, 325kg in hauling and 1750kg in surfacing. Those figures confirm the results obtained from the model experiments. 3) The sinking velocity of the bottom margin was about 7.0m/min and the sinking depth of the net foot was almost 102m. 4) As shown in Fig. 5 the normal transformations by operation of the net were influenced by the current, and the conditions most favourable for operation were Type A (no current), and B (mashio).