曳網中のヨーイングについて(日本航海学会第29回講演会)

抄録

The authors wish to show, in this report, the relation between the yaw-angle and the rudder angle during towing the net, which is thought to be one of the problems of basic importance specific to the fishing-boat, through the comparison of the records collected during towing with those during the ordinal navigation free from towing any net, although we know the occurrence of the phenomena probably with somewhat similar nature observable in the ships other than fishing-boat, for example, tug boat, etc. The details of towing the net vary with the fishing methods ; but, here, the authors take up the case of trawling, because the net is towed along straight line, consequently trawling is thought to be the simplest case and is easiest to analyze. While special attention should be paid to the fact that trawl-net is supported by "the towing block" on her stern at starboard side. So far as the present study has concerned, the following tendencies are found out: 1) In order to keep the ship with less stability of her head on her appointed course, towing makes the ship require the rudder angle larger than in the case towing no net. 2) The rudder angle during towing changes nearly in proportional to the yaw-angle with less deviation than in the case towing no net. 3) Undamped oscillation can be found during towing in either yaw-angle or rudder angle.