120 Part III. — Twentieth Anniuil Report 



the net) when fishing would be normally 80 feet. At Aberdeen five sizes 

 of otter-trawl are in use, the size being determined mainly by the size 

 of the vessel, as follows : — 



The last, which is used by a few of the smaller boats, is larger than the 

 otter-trawl as originally introduced, in which the headline was 75 feet in 

 length and the ground-rope 120 feet. There has thus been a consider- 

 able increase in the dimensions of the mouth of the net during the 

 seven or eight years it has been in use. The length of the net has not 

 increased in the same ratio; the largest measure abovit 145 feet in 

 length, viz., 90 feet for the square and top wings, 30 feet for the belly 

 and baitings, and 25 feet for the cod-end. The length of the large 

 beam-trawl nets (with a beam of 52 or 54 feet long) was about 115 or 

 118 feet, viz., 66 for the square, 25 for belly and baitings, and 24 for 

 cod-end, while the ground-rope was 120 or 124 feet in length. The size 

 and power of the trawling vessels have also increased ; it requires more 

 power to drag the otter than the beam-trawl. 



The attempts made to ascertain the di.stance between the boards, when 

 the net was fishing, by measuring the angle between the warps as they 

 diverged from the towing block, gave variable results. Some of the 

 cases may be referred to. In fishing in from 6 to 8| fathoms with a net 

 having a headline 102 feet in length, and Avith 37 fathoms of warp from 

 the towing block to the boards, the distance between the warps at a 

 point 22 feet 6 inches from the block was 5 feet 7 inches, indicating an 

 apparent distance between the boards of about 55^ feet. On this occa- 

 sion a cord 80 feet long, stretched between the boards, came up 

 unbroken. Another trial with the same net in eight fathoms indicated 

 an apparent distance between the boards of a little over 47 feet ; and on 

 this occasion a cord 70 feet long, stretching between the boards, was 

 found to be ruptured when the net was hauled, but this might have 

 occurred while shooting the net, or accidentally. On another occasion, 

 with a net having a headline of 108 feet and with 56 fathoms of warp 

 out while fishing in eight fathoms, the divergence of the warps indicated 

 a distance between the boards of 46| feet. 



Experiments were also made on board the " Garland," in January 

 1901, with a small otter-trawl having a headline 64 feet in length, the 

 otter-boards measuring 4 feet 6 inches by 3 feet 1 inch. In these cases 

 a bladder was tied to each boaixl with a string sufiiciently long to allow 

 it to float on the surface. Two row-boats were then stationed one on 

 each side of the course with a string between them, and the distance 

 between the bladders as they passed was measured. The particulars are 

 as follows : — 



I. Depth, 13i fathoms. Length of warp, 373 feet. 



(1) Ordinary speed. 



a Apparent distance between boards, calculated from divergence of warps, 



50-8 feet. 

 h Distance between bladders attached to boards, 35 feet 1 inch. 

 c String between boards, 45 feet, came up unbroken. 



(2) Full speed. 



a Apparent distance between boards calculated from divergence of warps, 



26 '& feet. 

 h Distance between bladders, 32 feet, 7 inches. 

 c String between boards, 40 feet, unbroken. 

 {3 Full speed. 



a Apparent distance between boards, calculated from divergence of warps, 



36 feet. 

 & Distance between bladders, 32 feet 7 inches. 



,, ,, ,, (again tried), 34 feet 5 inches. 



,, ,, ,, ,, 34 feet 7 inches. 



