14.5kc魚群探知機と、尖鋭ビームを有する200kc魚群探知機による同一海面に於ける測量図の対比(日本航海学会第19回講演会)

抄録

If the survey is made by the 200kc echo-sounder with sharp beam, the almost true shape of sea bottom is obtained within the error of 4% for the slope of bottom of 50° and 1% for 20°. We made survey by the 200kc fish-finder at the fishing-ground off Sanno, Odawara City on occasion of late. The difference, between the survey map by the 200kc fish-finder and that by the 14.5kc fish-finder the beam of which is not so sharp, is clear at the station where the shape of sea-bottom is complicated. The former is much more detailed and shows more closely the depth obtained by fisherman's experience than the latter. And the survey is easier by 200kc than by 14.5kc.