72 
BULLETIN 711, U. S. DEPARTMENT OE AGRICULTURE. 
As a rule, one choker is used with each log. One. two, and 
occasionally three, chokers are attached to a butt chain. Where 
more than one butt chain is re- 
quired, a rigging plate (fig. 26), 
to which a second butt chain is 
attached, is inserted in the main 
line about 50 or GO feet ir< m 
the end of the main line or the 
Fig. 
-Rigging plate. 
point to 
the usual bu.t 
) to 
chain is attached, the distance de- 
pending on the length of the longest logs hauled. 
Occasionally, it is necessary to use a yarding block 
side line the logs around stumps or other obstruc- 
tions, or to pull them backwards until they are clear. 
In the case of exceptionally large logs it is sometimes 
necessary to increase the power of the yarding engine 
by the use of a yarding block, When this is done, 
the end of the main line is attached to a tree along the 
road at some distance from the log in the direction of 
the yarding engine, a yarding block is hung in the bight 
of the line, and the shackle of the block is attached to 
the log. After the log has been moved up to the point 
where the line is attached to a tree, a new " tail-hold " 
is taken on another tree nearer the yarcler. 
The butt chain lead block, or bull block, has been re- 
placed to some extent by yarding or stump rollers (fig. 
28). This device allows the same speed with less fric- 
tion, and does away with the services of one man. By placing three 
rollers on the arc of a circle, it is possible and practical to log 
directly back of the landing without the 
use of a lead block. It has been estimated 
by an operator that the use of these rollers 
instead of lead blocks increases the output 
of a yarding crew between 9 and 10 logs 
per day, not taking into account the fact 
that the crew is reduced by one man. Of 
course, there are many chances where the 
use of a stump roller would not be prac- 
tical. 
Fig. 27. — Yard 
ing block. 
• ; . 
».i 
Fig. 28. — larding or stump 
roller. 
ORGANIZATION OF CEEW. 
The number of men in a ground-yard- 
ing crew varies by camps and in the same camp by chances, 
usual crew consists of the following 1 men : 
The 
