A DESIGN FOR THE STRUCTURE OF THE NET MOUTH OF ROPE TRAWL AND ITS RIGGING TECHNICS

This paper describes a design for the structure of the net mouth of the two-panelbottom rope trawl, the method calculating the lengths of the headline, footrope andhanging line, and the rigging technics. According to the different working conditions between the headline and footrope,the following formulas are adopted. The headline (assuming the parabolic form): y =a₀x²; s=integral from x₁ to x²(1+y'~3)~(1/2)dx The footrope (assuming the catenary form): y=a/2(e~(x/a)+e~(-x/a)); s=a/2(e~(x/a)-e~(-x/a)) Where y-rope length; x-horizontal distance; a,a_0-parameter; s-headline orfootrope length The rigging technology for the headline, footrope and hanging line was designedin accordance with the characteristics of China's bottom trawl. It has been proved thatthe design and rigging described above are useful.