| 摘要 |
Mesh bars (35, 283) of a trawl (13, 263) include at least a portion having a corkscrew-shaped pitch which exhibits a hydrofoil-like effect. Such mesh bars (35, 283) are preferably formed from a material having a substantially incompressible cross-sectional shape. By appropriately selecting the lay and leading edge of mesh bars (35, 283), movement of the trawl (13, 263) through the water entrained environment creates a pressure differential and lift across that portion of mesh bars (25, 283) which exhibit the hydrofoil-like effect. The lift thus created increases performance characteristics of the trawl (13, 263) including increased trawl volume, improved trawl shape, and reduced vibration, noise, and drag. Obtaining the greatest improvement of trawls (13, 263) requires controlling a pitch range for twisted product strands (e.g. twisted ropes) (36, 37), and for straps (284) forming mesh bars (35, 283). For straps (284), control of a width to thickness ratio also significantly affects performance of the trawl (13, 263). |
