. Science of the sea. An elementary handbook of practical oceanography for travellers, sailors, and yachtsmen. Fig. 200.—Ball Dredge.(After Wyville Thomson.) Fig. 201.—Agassiz Trawl,Blake Pattern. The beam trawl is towed by a pair of spans whichare shackled to eyes in the front of the heads. Eachspan should be three and a half or four times the lengthof the beam, and as stout as the warp. The head ropeof the net is as long as the beam, and is laced to it. THE BEAM TRAWL 297. The foot rope, to which the lower edge of the net isattached, is twice the length of the beam. The endsare securely lash
. Science of the sea. An elementary handbook of practical oceanography for travellers, sailors, and yachtsmen. Fig. 200.—Ball Dredge.(After Wyville Thomson.) Fig. 201.—Agassiz Trawl,Blake Pattern. The beam trawl is towed by a pair of spans whichare shackled to eyes in the front of the heads. Eachspan should be three and a half or four times the lengthof the beam, and as stout as the warp. The head ropeof the net is as long as the beam, and is laced to it. THE BEAM TRAWL 297. The foot rope, to which the lower edge of the net isattached, is twice the length of the beam. The endsare securely lashed to the eyes at the back of the heads. 298 DREDGING AND TRAWLING As it is intended to scour the bottom, it is necessaryto make the foot rope heavy; for medium-sizedtrawls 8-inch rope is recommended, weighted by theattachment of lengths of chain. The net should be about one and a half times thelength of the beam. It is made of hemp or manilatwine of 2 to 2j inch mesh in the back and belly,and i inch double mesh in the cod end. The lowerpart of the cod end, which comes in contact with theground, is protected from chafe by an extra piece ofstout netting attached on the outside. The trawl moves comparatively slowly over the seabottom, and consequently fish which have entered thenet frequently manage to swim out again and avoidcapture. To obviate this, pockets are formed bystitching together the back and belly of the net at thesides, as indicated in Fig. 202. The net is
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Keywords: ., bookcentury1900, bookdecade1910, booksubjectocean, bookyear1912
