抄録
The samples of net disused after their usage in purse seine fishings were obtained from various fishing ports and examined of their properties in order to formulate the knowledges about the safty limit of their utility taking into account of the peculiarities in the disposition of the net as well as the circumstances in which the net is used. (Table 1)
The mesh sizes of the nets being already out of use are shown in Table 2.
The knot strength was adopted on this occasion as the measure of netting strength. To determine the knot strength each two of the four arms around a knot were gathered and streached by a tensile tester.
Now, if minimum strength allowable for netting of purse seine is denoted by Tu, we get the following equation:
Tu=κDB2
where the various letters have the following meanings respectively: κ, constant number; D, diameter of netting thread; B, the greatest depth of net.
