[TowerTalk] Gin Pole Strength

[Gary McDuffie, Sr.]

On Sat, 3 Apr 1999 02:59:37 +0100, Hans K0HB wrote:

> Wrong.  Just plain wrong.  While the block and tackle gives
> you a mechanical advantage, the gin pole is carrying
> *only* the weight of the antenna (200 pounds), either with
> a single pulley at the top, or with the multiple pulley
> arrangement of the block and tackle.  In fact, the added
> weight of the extra pulleys and rope places a greater
> strain on the gin pole than just a single pulley at the
> top.
> 
> 73, Hans, K0HB

Hans, I said the same thing, but I think I've been converted.  I'm the
one who first posted a rebuttal to the original comment about decreasing
the load with a 3:1 block and tackle.  I really thought I was right and
anyone would be a fool to disagree.

However...

The latest revival of this thread got me thinking.  I didn't believe it
until I thought of it this way:

If you hang a 200 pound weight from the gin pole (tied off at the top),
the gin pole would have 200 pounds pulling down on it (forget the weight
of the rope and extra stuff).  Now, if you untie the rope and hang a
weight on the end of it (through the pulley), you would have to hang 200
pounds on the end of it to keep it balanced (or move it).  You would
then have 400 pounds hanging on the gin pole.

It still confuses me to think of it!  Anyway, see what you can do with
that method of looking at it.  I'm really curious about this now.  I had
thought this started off as a very simple thread with an answer I knew
was right.  Now, I'm thinking I was wrong (and my apologies to the
person I originally rebutted).

Gary
-- 

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