Taylor and Wells. — Preservation of Nets and Lines. 63 



Copper oleate being by far the lighter of the more effective 

 preservatives, has a great advantage over tar, and deserves 

 further study and consideration as a preservative for large heavy 

 seines where tar is now used. 



RESISTANCE AGAINST FOUIvING BY BARNACLES, HYDROIDS, ETC. 



It has already been shown that in those circumstances where 

 stiffness and weight of lines was not a very important factor, 

 numerous preservatives were available to prolong their strength 

 and wearing qualities. It is only in the case of traps, pound nets, 

 and stationary gear of various kinds that stiffness and weight 

 are of minor consideration. But since the nets remain in the 

 water for long periods, another important factor arises, namely, 

 fouling by barnacles, hydroids, and other attached organisms. 

 The disadvantages brought about by the growths are numerous. 

 (1) They greatly increase the weight of the nets, thus increasing 

 the labor and time required to fish them; (2) the extra weight 

 (which may greatly exceed the original weight of the net) puts 

 an added strain on the net ; (3) the accumulation of growths on 

 the net increase the collection of floating debris from the water, 

 thus further straining the nets; (4) the net offers greater re- 

 sistance to stream and tide flow when fouled, and is consequently 

 put under greater strain ; (5) these growths, especially barnacles, 

 injure the fishermen's hands. 



Tarred lines, though fairly well preserved in strength, yield 

 readily to fouling with barnacles and hydroids; so do lines treated 

 by Petroleum Products Nos. 1 and 2, Bull's method, and Gilso- 

 nite. Those lines treated with preservatives which contain copper, 

 even in small amounts, resist fouling. Lines treated by the 

 Dutch method fouled somewhat in four months at Beaufort. 

 Those tested with copper paint, and all those treated with either 

 of the copper oleates, were, after the fourth month in the sea 

 water at Beaufort, entirely free from all attached growths visible 

 to the eye. The tiny amount of copper which remained in the 

 lines (2 to 4 mg. per yard, as shown by a determination of the 

 copper present) shows the effectiveness of copper in preventing 

 fouling. Of course, copper oleate can and should be applied in 

 much heavier concentration on lines to be exposed continuously 

 in the water. The advantages brought about by this single point 

 of superiority would, even if there were no others, alone justify 

 the use of copper in lines for continued submersion. 



