Mechanical properties of a rectangular purse seine in a normal operation

The mechanical properties with factors of forces (tension; F and drag; D), velocity (v) and distance (s), in a normal operation were studied. Normal operation means pulling both ends of the purse line by a winch during the pursing stage and the hauling stage. The mechanical pro-perties at the equilibrium condition of the force were expressed in the pursing stage (suffix “1”) as; η1=e-πμ1, F1=(Fwcosθ1)/2, D1=πη1Fwcosθ1, v1=(Vwcosθ1)/(πη1) and s1={(Vwcosθ1)/(πη1)}t, where θ1=sin-1 (W/Fw), and in the hauling stage (suffix “2”) (vertical pulling) as; v2=1.0, F2=Fw/2, D2=Fw-W, v2=Vw and s2=Vw(t-t1). Where η1 and η2 are the mechanical ef-ficiencies between the purse line and the ring, μ1 is the kinetic friction coefficient between the purse line and the ring, Fw is the tension of the winch, W is the weight in water of the fishing gear, Vw is the velocity of the winch, and t1 and t2 are the time lapses during a fishing operation. If the factors μ1, Fw, W, Vw, t1 and t2 are given as known constants, each factor of the mechanical pro-perties can be calculated.