350 
BULLETIN OP THE UNITED STATES FISH COMMISSION. 
wrought iron, is in two parts with jaws on each side, through which l^-inch bolts are 
passed and set up with nuts. When i)roperly adjusted, there remain intervals oi' 2 
inches between the jaws, and in these spaces, supported by the bolts, hang two links, 
one on each side, to which the topping lift shackles. An eye in the forward part of 
the band supports the accumulator, which is shackled to it. 
THE ACCUMULATOR. 
The accumula tor xxxi) performs the several functions of relieving the dredge 
rope from jerking strains brought upon it by motion of the vessel in a seaway, insuring 
a more uniform action of the hoisting engine and giving the first warning of increased 
tension on the rope in case the trawl fouls or buries in the soft bottom when working 
in deep water. It also acts as a dynamometer, indicating through a graduated scale 
the strain to which the rope is subjected. 
The (juide rodn c are made of a single length of round mild steel 1 inch in diame- 
ter, bent at e and /, with screw threads and lock nuts at h. The tension rod is of mild 
steel, round in section, inches in diameter, and 9 feet 9 inches net length — that is, 
measured inside the crosshead i and yoke I'. It holds 39 buffers without compression, 
and usually carries 44 in service. It has a swivel link at the lower end, to which the 
accumulator block shackles, and a screw thread and lock nuts (j at the other extremity. 
The total length of the accumulator, including the links at each end, is 12 feet 1 inch. 
The crosshead i, yoke h, and tie-])]ate I are of wrought iron; the former move 
freely on the guide rods c, the upper one receiving the ends of the tension rod d and 
scales 7)1, while the lower ones support the guide rods and scale bars. A front view 
of the tie-plate I is shown in fig. 3, the two vrpper crossheads i in fig. 4, while fig. 7 
shows the lower crosshead i with slots in each end through which the scales slide. 
The slots are made wider in the middle section to protect the painted marks on the 
scale bars. There is a brass washer b between each rubber buffer, as seen in fig. 2, 
where they are shown in section; they are 6| inches in diameter, inch thick, with 
a hole 1-1% inch diameter in the center. Hubs one half inch in length extend from 
each side of the washers (figs. 5 and 6), except those in contact with the yoke and 
crossheads, which have no hub on that side. The buffers were furnished by the 
New York Eubber Belting Company, and are composed of their No. 23 compound; 
they are 5.^ inches in diameter, 3 inches thick, and have a hole l-%g inch diameter 
through the center. They weigh 4 pounds 3 ounces each and cost 67 cents per pound. 
The scales ui are composed of two fiat bars of iron, 1| inches wide and J inch 
thick, attached to the sides of the accumulator, as shown in fig. 2. The upper ends 
are round, and carry screw threads and nuts, by which they are secured rigidly to 
the upper crosshead; thence they i)ass down through holes in the upper middle 
crosshead and through slots in the lower crosshead and yoke. The scale bars are 
graduated from the lower ends by putting gradually increasing strains on the dredge 
rope, rove through its blocks as for service, and to avoid accident under the higher 
tensions it is customary on board the Albatross to lay accumulator and blocks on deck 
or on a wharf and to use new rope; the divisions are made by painting white marks 
of different widths across the bars, the narrow ones representing 500 and the wide 
ones 1,000 pounds. The graduations once made, adjustments, incident to long service 
or climatic influence upon the material of the buffers, may be effected by the nuts at 
the upper ends of the scale bars. 
