Diving Plate Modification of Blake (Beam) Trawl for Deep-Sea Sampling

During bottom trawling at great depth, it is often necessary to attach heavy weights ahead of the trawl to reach the bottom with the wire available. These weights effectively decrease the wire angle and increase the depth of the bottom which may be sampled. During Cruise 6 of the National Science Foundation-sponsored Antarctic research ship, the USNS Eltanin, it was found that a 272-kg block attached ahead of either the 1.5-m or 3-m Blake (beam) trawl reduced the wire angle but caused the trawl to tumble when on the bottom, resulting in poor hauls, in which the net was torn or fouled or the trawl was lost. Two trawls, with blocks, were lost during Cruise 6. Further reduction of wire angle could be achieved by drifting during the trawl, but this often resulted in a fouled net.