Abstract: 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).

Abstract: Mesh cells (30) for machine-made netting (51) use pairs of mesh bars (35) made from a continuous length of material and meet at a common coupler (34). Such mesh bars (35) have a lay with a common direction throughout the length of material. In a zig-zag pattern used in knitting machine-made netting (31), the longitudinal axis of symmetry (38) of mesh bars (35) turns at each coupler (34). Towing such mesh bars (35) causes water to flow past pairs thereof in two different directions with respect to their common lay. The directions of water flow are neither parallel nor perpendicular to the longitudinal axis of symmetry (38) of the mesh bars (35). As water flows past the mesh bars (35), the cross-sectional shapes of the mesh bars (35) produce a net component of force that is oriented in a direction perpendicular to a combined drag component of force for the mesh bars (35).