LARGE PLANKTON NETS iii 



the circumference, although in practice, to make sure that the net is completely strangled, 

 a somewhat longer drop is required. Equally effective throttling can be obtained by 

 either arrangement, but of the two the second is much to be preferred, since with its 

 shorter drop it is less inclined to strain the gear — a matter of major importance where 

 heavy deep-sea apparatus is concerned. 



Until it has come into play, that is while the net is still fishing, the stray line is coiled 

 small behind the release gear and stopped off with sail twine, otherwise its loose bight 

 might become involved in the twisting warp, or by fouling the closing mechanism 

 precipitate release. The arrangement of the stray line is shown in Figs. 2 and 3. 



Fig. 3. Large closing nets: details of the arrangement of the gear behind the closing mechanism, a, stray 

 line ; b, throttling rope ; d, bridles ; h, hauling rope to net ring ; r, closing mechanism ; w, warp. 



It is interesting to recall that an internal closing arrangement, acting in the opposite 

 direction but essentially similar in principle to that which has just been described, had 

 been employed by Kemp^ some ten years previously for sending down large mid-water 

 nets closed and opening them under water. 



So far the new internal throttling arrangement had only been employed with the 

 young-fish trawl, mounted as already described on a 2-metre ring: whether it could be 

 applied as it stood to the much larger and heavier N 450 with an opening five times the 

 area was a matter for some concern, for to close the N 450 as it would normally be 

 closed, that is by throttling at the canvas band (Fig i ,/) where the circumference is 50 ft., 



^ Kemp, S., loc. ctt., p. 202. 



