Methods for the Theoretical Calculation of Wing and Door Spread of Bottom Trawls J. Dalmendray Gómez and J. R. Valdés Jiménez
Department of Fishing Gears, Center of Fishing Research
Barlovento, Santa Fe, Ciudad Habana, Cuba
Source - Journal of Northwest Atlantic Fishery Science, Volume 16: 41-48
ISSN-0250-6408
Baranov's (1969) and Carrothers' (1980) methods of theoretical calculation of trawl door spread and methods to calculate the wing spread are discussed. Baranov's formula was simplified and a correlation between the net drag of the trawls (as a measure of the system's size), and the differences between the measured values of door spread and its calculation by Baranov's equation was found, thus making it more accurate. For four-fifths of trawl nets under study the value of those differences were below 7%. It was evident that Baranov's formula fitted better than that of Carrothers' for the experimental door spread values of the sample. An empirical formula is proposed for estimating wing spread of bottom trawls. The differences between calculated and measured wing spread values are under 17% in 90% of cases. Since the order of accuracy obtained with described formulae is within the range of variation of experimental results, the level of agreement is felt to be acceptable.
Language - English
Publisher - Northwest Atlantic Fisheries Organization (NAFO), Dartmouth, N.S., Canada
Publication Date - July 1994
Publication Type - Journal Article
Descriptors - bottom trawl, gear, trawl geometry, wing-door spread