[TowerTalk] Taking down a tri-ex LM354

[Richard (Rick) Karlquist]

On 6/8/2014 6:12 PM, Jim Lux wrote:
>
> If you don't have heavy lifting gear, then the next thing is a falling
> derrick rig and a suitable winch/come along/tow vehicle, etc.  The
> falling derrick helps insure that as your tower comes down past the 45
> degree point, the load is still reasonable.
>
> If you have 15-20 feet of suitable tower sections, you could probably
> also rig up some sort of guyed vertical pole with a block and tackle
> anchored at the top to help lay the other tower over.

A word of caution on the falling derrick method.
If you build a falling derrick to put a tower UP, the
first 6 inches are the most difficult.  So it is
risk free to test the set up by raising the tower
6 inches and seeing if anything goes wrong.  I
did this with my 50 ft Glen Martin tower and found
out that the derrick was well on the way to buckling.
Fortunately, I had the luxury of backing down and reinforcing the
derrick before trying again.

If you build a falling derrick to put a tower DOWN,
and didn't use it to put the tower up in the first
place, you have no way to test it.  You might have
the tower within 10 feet of setting down and then
the derrick buckles or something.  In your case,
it might be a one time use derrick, where you don't
want to waste money over designing it.  Cut corners
at your own peril.  Be sure to side guy the falling derrick.
Be careful.  Borrowed tower sections are greatly preferred
over water pipe.  Very hard to predict when a pipe is
going to buckle.

Rick N6RK