POWER SKIDDING 243 
be taken, and directs and assists the rigging slingers in their 
work. The head rigging slinger is the hook tender's assistant 
and working alone or assisted by one or two helpers, he unhooks 
the chokers from the butt chain when the main cable has been 
returned to the log, hooks up new turns of logs, and sets "lead" 
and other blocks when they are required. The swamper works 
just ahead of the rigging crew, knots the logs, chops out the 
small trees and brush, cuts roots and improves the runs so that 
logs can be brought in without being hung up. The chief duty 
of the choker men is to place the chokers in position on the log. 
The sniper rounds the forward ends of the logs so that they will 
more easily slide over obstructions. The chaser passes logs by 
the butt-chain blocks and unhooks the logs at the landing.^ 
The signal man transmits the orders of the hook tender, rigging 
slinger, or chaser to the engineer either by pulling on a wire at- 
tached to the whistle of a yarder or by means of an electric whistle 
control operated by batteries. 
The daily output of ground yarding equipment is extremely 
variable but ranges between 40,000 and 80,000 board feet. In 
some cases a higher output has been secured for short periods 
and in other cases it has fallen below the minimum men- 
tioned. 
High-lead yarding.^ — In this system the main cable passes 
from the machine through a block suspended 125 or more feet 
in the air from a nearby spar tree and from thence to a block at 
the far end of the run. The haul-back line follows the general 
ground level. Although this method was known in the West as 
early as 1905, it was not extensively used until about 1915 since 
which time many installations have been made.^ This method 
is not commonly employed in other regions due to the absence 
of trees of a suitable size and height for spars. The system has 
1 When the butt chain blocks are some distance from the landing an extra 
man may be needed to tend them. - Their use is becoming less frequent for 
this reason. 
2 See Fig. 77. 
' The high-lead method was used in the South some years previous to 1905. 
A patent on a high-lead system for western use was granted to H. R. Robinson 
in 1905 and in a later suit brought to collect royalty from loggers who used 
that method it was brought out that similar patents had been issued several 
years previously and that machines built imder the earlier patents were in 
operation before the Robinson patent was granted. 
