80 REPORT OF COMMISSIONER OF FISH AND FISHERIES. [78] 



They are bolted to a block of wrought iron 5J inches in length, 2J inches 

 in width, and 2^ inches in depth, having a hole If inches in diameter 

 through its center in which the shackle bolt d is secured. This bolt 

 acts also as a swivel. The sheave b is made of composition 21£ inches 

 total diameter, 18 inches at the bottom of the score, and 2J inches in 

 width. The pin c is of cast steel, and is surrounded by six cast-steel 

 frictiou rollers i, 1\ inches in diameter, which work on the inner surface 

 of a wrought-iron bushing in the sheave. The guards h are used on 

 the block at the boom end, to prevent the dredge rope from flying out of 

 the score, and the arm j is used on the accumulator block for the for- 

 ward guy which hooks in the eye k. The absence of the guards h in 

 one block, and the arm j in the other, constitute their onty points of 

 difference. 



THE ACCUMULATOR. 



The apparatus shown in Plate XLIV performs the double function of 

 accummulator and dynamometer for the dredge rope. 



NOMENCLATURE. 



a. Buffers. 



b. Washers. 



c. Guide rods. 



d. Tension rod. 



e. Link. 



/. Swivel link. 

 g. h. Lock nuts, 

 i. Cross-beads. 

 j. Yoke. 

 k. Tie. 



The accumulator is shackled to the topping-lift band 13 inches below 

 the futtock band on the foremast, and is suspended directly forward of 

 the mast. Its total length, including the links e and/, is 11 feet 1 inch. 



The guide rods c c are made of one piece of round mild steel, 1 inch 

 in diameter, bent at e and Jc, with screw threads and lock nuts at h h. 

 The tension rod d is also of mild steel, round in section, 1^ inches in di- 

 ameter, and 9 feet 9 inches net length, that is, measured inside the 

 cross-head i and yoke j, and it will take thirty-nine buffers without com- 

 pression. It has a swivel link at the lower end, to which the accumu- 

 lator block shackles, and a screw thread and lock nuts g at the oppo- 

 site extremity. 



The cross-heads i i i, the yoke j, and the tie k are of wrought iron ; 

 the former move freely on the guide rods, the upper one receiving the 

 end of the tension rod, and the others support the guide rods. Figs. 

 3 and 4 show a front and side view of a cross-head. 



There is a brass washer h between each pair of buffers, separating 

 them from each other, and keeping them from contact with the tension 

 rod, as seen in Fig. 2, where the washer and buffers are shown in sec- 

 tion. 



