[TowerTalk] Tie ropes to rotating mast?

[Dan Levin]

I have a 70' HD crankup with a 16' high quality steel tube mast sticking out
the top.  The bottom 8' of the mast is in the tower (24' total mast length),
rotated by a T2X and supported by a thrust bearing.

I have two tall trees on my property.  If you were looking down at the
property with the tower as the center of the clock, the trees are at 3:00
and 7:00 or so.  I want to run ropes from each tree to the tower to use as
supports for vertical wire antennas.  I strongly prefer to attach the ropes
to the tower above the top of the tower itself, in order to achieve greater
height.

My current installation involves a 6' piece of pipe that sticks into one of
the legs of the tower.  I then tie off the ropes to the top of this pipe.
It works fine, but the pipe takes a great deal of stress from the ropes, and
is only 6' above the top of the tower.

I am thinking about bolting a metal block onto the mast, and the putting a
lubricated bearing of some sort above that with the ropes tied to it.  The
idea here is the the block will keep the bearing from falling down.  The
bearing will probably be a couple of pieces of delrin bolted together to
form a sleeve over the mast, with a teflon bearing surface between the
delrin and the mast and the delrin and the steel block.  The block will
rotate with the mast, the delrin will stay in place and the mast will rotate
inside of it.

The advantages here are that I get to use the mast, which is mechanically
strong, instead of the 6' pipe, which is less strong; and that I could mount
the ropes higher than 6' above the top of the tower.

The obvious questions are:

1) Will the delrin prevent the mast from rotating?
2) Will the pull of the ropes on the mast create a problem of some kind?
NB: The total force of the ropes is very small relative to the force
generated by the C-3E at the top of the 16' mast :-)

Thoughts, suggestions, etc. welcome.

As always, thanks much in advance.

             ***dan, N6BZA


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