Carriages
Carriages
come in many different designs and sizes. ranging from simple to complex.
I'll start at the beginning, keeping in mind that this site mainly is concerned
with skyline applications there are many other types of setups that will
be not mentioned here. The first type of carriage is simply a block hung
upside down from the skyline with some chokers hooked to it, either the
skyline has to be close enough to the ground to let the chokers reach the
ground or the skyline has to be raised and lowered with each turn of logs.
The next type would be the Christy Carriage, this unit has two pulley's
inside of it where one rides the skyline and the other is for the mainline.
When this unit comes down the hill, there is another object clamped on
the skyline that is set by the choker setter to stop the carriage at his
desired location. After the unit has come to a stop, the skyline is lowered
enough to allow the crew to reach the chokers so they can pull the line
to the logs to be skidded. both the above mentioned applications work just
fine in a limited range, but there are far too many situations out there
for those to work all the time, that is where this next type of units came
to life.
Motorized carriages.
These units have a small diesel engine inside of them that runs a variety
of things, they have a hydraulic system that is used for the skyline clamp
and skid line clamp. The skyline clamp is used to hold the carriage in
place under it's own brake. The skid line clamp is used for situations
like if you have a turn of logs hung up 100 feet from the carriage and
you need to move the carriage up or down the hill, clamp the skid line,release
the skyline clamp and adjust carriage as necessary to snake the logs through
the standing tree's. These carriages have slack pulling capability, when
the unit is locked in one place on the skyline, it will then spit out as
much slack as needed to reach your logs. The almost instant adjust ability
of these carriages make them the best possible choice for select harvesting.
After that we
move on to the full blown motorized carriage. this unit has a large engine
inside of it and carry's it's own skid line winch. When the carriage is
out in the brush the choker setter signals the carriage rather than the
yarder to drop the line, and when the logs are hooked up it is again the
carriage that yards the logs up to itself. Another advantage is if you
have a lot of distance between the ground and the skyline is that the drop
line can be already putting out slack while the carriage is on it's way
down the hill. The major disadvantage used to be that these things weighed
around 8000 pounds and cost over $100,000.00 dollars. But a company called
Boman Ind. in portland oregon has just developed a new smaller model of
these units weighing less than 2 tons and a cost of around 25 thousand
dollars.
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