EQUIPMENT. 
31 
when there is a great weight in it, or when the vessel is pitching. 
The curve made by the wire rope, as it leads from the vessel 
to the trawl, is of itself the best accumulator, as a com- 
paratively slight strain will constantly tend to change 
the form of the catenary. It is only while hoisting 
the dredge that the accumulator is useful, and long 
before it works to its full power the changes of form 
of the catenary of the wire rope, from an easy winding 
in of the dredge to the fouling of the same, will pro- 
duce a greater or less strain, entirely unnoticed, on the 
accumulator, if (as in our case) the strain is less than 
two thousand pounds. The friction of the steel rope 
against the wire, even when two or three thousand 
fathoms of wire are out, is far less than the breaking 
weight (eighty-six hundred pounds) of the steel-wire 
rope (one and one eighth inches circumference) used 
on the “ Blake.” 
The steel rope was hoisted by a small double-cylin- 
der winding-engine, with a surging-drum, from which 
the rope then passed to the reel, where it was coiled 
as closely as practicable. The reel was managed by 
a pair of small engines used to wind the line, and by 
a friction-brake when the rope was lowered. 
In dredging, the dredge or trawl was invariably 
lowered independently of the winding-engine, from 
a reel built especially for the work. This reel, built 
of iron, consisted of a hollow axle two feet in diam- 
eter, four feet long, flanked by flanges extending 
eighteen inches above it, capable of winding about 
four thousand fathoms of one and one eighth inches 
steel-wire rope. The axle upon which the reel ran 
was supported upon bearings carried upon a strong 
КҮКҮ ҮРЕ кЕ n 
Ett ШЫ БШ БШ ШН ЖЫ БЫ ЮШ ЭШ ЧЕП ЕШ ӘН ЧӘ" 
ti 
Fig. 28.—Ac- 
cumulator. 
(Sigsbee.) 
iron frame securely bolted to the deck; the reel was checked 
by a band friction-brake, by which one man could readily con- 
trol the velocity of the steel rope as it was unwound and could 
accurately regulate the speed. The brake was of 
sufficient 
strength to stop the dredge even at a depth of nearly two 
thousand fathoms; and while dredging or trawling, the brake 
