48 THE FISHING INDUSTRY 



The otter trawl that is used by modern steam trawlers 

 is from seventy to one hundred and twenty feet wide 

 across the mouth, according to the character of the 

 fishing, and a hundred and ten feet long from the mouth 

 to the cod encT The otter trawl is shown in Fig. 17. 

 It differs from the beam trawl in that its mouth is kept 

 open, not by being attached to a beam, but by otter 

 boards, which are attached one to each side of the mouth 

 of the net. These are attached to the net and to the 

 warps by which the net is towed in such a way that the 

 pressure of the water upon them causes them to diverge, 

 thus keeping the mouth of the net open. The size of a 

 beam trawl is necessarily limited by the length of beam 

 obtainable. The size of the otter trawl, however, is 

 obviously only limited by the power of the steam 

 trawler. The otter boards measure 11 ft. by 4 ft. 6 ins., 

 are shod with iron, and weigh 15 cwts. each. The 

 warps, as the ropes are called which attach the otter 

 boards to the ship, are from three hundred to a thousand 

 fathoms long generally a little over three times as 

 long as the depth of the water in which the trawl is to 

 be used. Each board is attached to the steamer by a 

 separate warp. The upper edge of the mouth of the 

 net is attached to a strong rope, called the " head " 

 rope. The lower edge of the mouth of the net is also 

 attached to a strong rope, called the " foot " rope. As 

 in the beam trawl, the foot rope is considerably longer 

 than the head line, and forms a bosom. Traps and 

 pockets also are inserted in the sides of the net. When 

 trawling on rough ground, the foot rope is furnished 

 with large, heavy, wooden rollers, called the " bobbins." 



Trawl fishing, until quite recently, was almost entirely 

 confined to demersal fish, such as cod, plaice, haddock 

 and halibut. In recent years, however, considerable 

 quantities of herring have been caught by trawlers. 



