"groundropes" - 1 õppematerjal

Traapüük

Skväär Kere Kere Pära 10 11 12 The essential elements of twin rig trawl gear are set out in Figure 11. This gear is generally used for target species tight on the bottom, such as angler, flatfish and Nephrops. By towing two nets side by side the effective swept area, and hence catch, is increased. As with the single demersal trawl above, otter boards (a) provide the horizontal spreading forces and floats and groundropes the vertical forces. The obvious difference in rigging is the third wire or central warp (b), which runs from the vessel to the clump (c), a heavy weight which can consist of short lengths of chain cable shackled together or a custom made device (Fig. 12) designed to roll rather than be dragged along the bottom. Warp length/water depth ratios are similar to those used with the single demersal trawl and bridles/sweeps (d) can be steel wire, combination wire, chain or a mixture of all three