72 



BULLETIN 711, U. S. DEPAiITMEl\-T OF AGRICULTURE. 



Fig. 20.— Rig 



plate. 



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. 2G), 

 to which a second butt chain is 

 attached, is inserted in the main 

 line about 50 or GO feet from 

 the end of the main line or the 

 point to which the usual butt 

 chain is attached, the distance de- 

 pending on the length of the longest logs hauled. 



Occasionally, it is necessary to use a yarding block (fig. 27) to 

 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 j^arding 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 yarder. 



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 da}^, 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. 



Fig. 



28.— Yarding 

 roIliT. 



or stump 



ORGANIZATION OF CEEW. 



The number of men in a ground-yard- 

 ing crew varies by camps and in the same camp by chances. The 

 usual crew consists of the following men: 



