CH. l] 



THE EXPLORATION OF THE SEA 



19 



the form of the two instruments is the same. A useful modifica- 

 tion of the shrimp trawl is the " shank net," which is essentially 

 a trawl, the mouth of which is kept open by a, fi-ame of wood 

 about ten feet long by one and a half to two feet wide and one 

 side of which drags on the ground. 



In a small steamer or a sailing vessel the trawl is towed by a 

 rope of hemp or steel wires which passes over the rail through 

 towing chocks and is coiled loosely round the bollards. The trawl 

 rope is attached to the bollards by means of a " stopper." This 

 takes the strain of the tow^ and should the trawl catch on any 

 obstacle on the sea bottom and be " brought up " the increased 

 strain is thrown on the stopper, which then parts, warning being 

 then given to stop the vessel and get the net loose. In this case 

 the slack of the warp is taken in and the vessel then sails round 

 the obstacle, when the trawl is usually detached. 



In Fig. 9 I give a diagram of the arrangement of the trawl, &c. 

 on the deck of the ship when it is in readiness for " shooting." 



Fig. 8. Diagram of an otter trawl. 



The beam lies along the starboard rail, the after iron projecting 

 over the counter and the forward iron just inside the rail. The 

 latter is lashed to a stanchion and the former to a small davit 

 over, which the rope is passed when the net is being hauled. 

 The bridles are loosely coiled up on deck out of the way of any- 



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