Either help the OP or give facts, a diagram, or a formula that
presents your worries and concerns. Continually repeating that
someone is wrong solves nothing, helps nothing, changes nothing.

Perhaps you did not notice that OP intends to try his original
concept - win, lose, or draw. He will be watching for empirical
evidence that he is underdesigned.

I would point out that I just loaded on my trailer two pieces of
2x2x1/4 wall twenty foot sticks that had been unloaded with a
single choker at mid point. They both have a permanent 2-3" crown
in them. Too good to toss, too bent to use without
modification/adaptation. Could not be used on this job for their
original intent.


^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
Keep the whole world singing . . . .
DanG (remove the sevens)




"Bill Schwab" wrote in message
news
Chris,

Bill Schwab wrote:

snip


You mean C:\docs\davit_calc2.jpg? If so, isn't that the pin
you said doesn't act on the beam? If that's the case, then
we're back to the missing horizontal force.


The pin does not transmit the horizontal component of the
tension to the top end of the column, if you accept the
idealised joint I proposed. This does not mean that the pin is
unable to transmit any horizontal force to the column. It does
provide a horizontal reaction which opposes the compression in
the horizontal beam. This is a subtlety of the idealised joint,
which you may like or dislike, but the FBD is consistent with
the idealisation.

I call it quits.

What you describe is almost certainly either unsupported, or
statically indeterminate. Even if you have designed something
that is determinate, it is by no means a simplification relative
to the what was presented to you in your mechanics classes. If
you think the pinned frame is complicated, you didn't learn the
material.