Graduate School of Fisheries Sciences, Hokkaido University, Hokkaido 041-8611, Japan
The calculated velocity of a jig hauled with a commercial hexagonal drum and a regular nonagonal drum on an automatic squid jigging machine, was compared with the measured velocity. The measured and calculated leader line velocities were found to be in agreement, however, the calculations failed to reproduce the vibrations that were observed in the leader line due to jigging.
The variations in jig velocity for a constant velocity drive were small for the regural nonagonal drum, which had a hauling effect similar that of a cylinder, whereas the variations were marked for the hexagonal drum, which was rhombic. It was found that when using an accelerated drive with the hexagonal drum, the guide roller needs to be set appropriately in order to increase the jigging effect.
To induce the magnitude of jigging required for catching squid requires a rotational velocity of 20-110rpm, besed on manual rotaion of hauling drum. In the operating conditions in this study using a 0.4kW motor, it was not possible to vary jig velocity in a single rotation of the hauling drum.