POWER SKIDDING 229 
Other Systems.^ — There are numerous other systems of over- 
head skidding which have been developed in the Northwest, 
which differ only in minor details from each other. Some are 
used for yarding purposes and others for "swinging" or "roading" 
logs. They were first developed to solve some particular logging 
problem of an individual operator and the early types were de- 
signed to utilize available ground-yarding power for their opera- 
tion. Later improvements have led in some cases to the use of 
a special design of power and certain other working parts which 
have made the systems more efficient. 
THE SNAKING SYSTEM 
This is a ground system in which the cables are taken to the 
logs by animals. 
It has a vertical, high-pressure boiler with two, three or four 
independent skidding drums mounted either on a heavy steel 
frame and trucks or on a steel frame which is supported at the 
corners on legs or "spuds." The first type is transported under 
its own power by a chain drive, and the latter type during transit 
rests on a flat car which is drawn by a locomotive. 
The machine has a heavy pulling boom at one or both ends of 
the frame, from the peak of which blocks are suspended through 
which the skidding lines pass. The pulling booms are guyed on 
either side to give them rigidity. 
Self-propelling snaking machines are not equipped with a loading 
device but are supplied with a decking cable by means of which 
logs may be piled up along the track ready for a special loading 
crew. 
When the snaking machine is not transported on its own 
trucks, it is equipped with a loading boom and the logs are loaded 
on cars as they are skidded. The machine is elevated above 
the flat car by means of hydraulic jacks and then the corners are 
blocked up. The log cars are run under the skidder when they 
are brought to the woods and are pulled forward under the 
loading boom by means of a "spotting" cable as required for 
loading. The skidding cables are single lines which are carried 
1 See Logging in the Douglas Fir Region, by W. H. Gibbons, U. S. Dept. 
of Agriculture, Bui. No. 711 for a description of some of these systems. Some 
overhead equipment, used chiefly or solely for swinging, is described in Chapter 
XIV. 
