The G.O. Sars has a drop keel.
|This addition is necessary to increase the accuracy of data collection. |
|Scientists use transducers to count fish. Hull-mounted transducers function perfectly adequately in calm waters. In bad weather (high winds, storms), however, turbulence along the hull surface produces a layer of bubbles which interferes with sound propagation. These bubbles confuse the transducer recording system and the data recorded under such conditions imply that fewer fish are present. Drop keels were developed to avoid this problem. |
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| ||Ref: J. C. Novarino and D. R. Bruno: Effects of bubble layer on sound propagation, J.Acoust. Soc. Am., Vol. 72, No. 2, August 1982 |
|Much fewer fish is counted when a transducer is mounted on the hull, then on a drop keel. See plot: |