| If the vang will hold the boom down under heavy sailing loads, then it
| will probably hold at least as much in the opposite direction, nyet?

Capt. Mooron wrote:
No Doug! No No No!.... look the vang may be able to hold the stresses on a
sail "down"... but it will never hold the stresses of a weight at the end of
the boom "UP".

Why not? If the boom can take the torsion in one direction, then unless
it is a very weird asymmetric structure, then it will take the same in
the opposite direction.


... The leverage just isn't there.

Sure it is. It's exactly the same in both directions.

What I'm saying is the same as saying if you can stand on a beam (let's
say a 2x6) between two sawhorses, and it doesn't break, then you can
turn the beam over and still stand on it. You're saying that it doesn't
work that way, if the beam doesn't break one way then it will definitely
break the other...

.... This is not a hydraulic arm on
an excavator! If it were the vang would be massive ... require an engine to
power the compressor and be attached to the end of the boom.

The max forces are limited by the righting moment of the boat. On a 30
footer, it doesn't need to be that massive. On bigger boats... take a
look at the vangs on IACC racers...


Look..... I can understand where your assumptions are based but I'm
thinking you have not taken into consideration the engineering incorporated
into the vang and it's intended use.

Actually, I have. It's not that complicated. Try drawing out a diagram
of moments. If you need a refresher
http://www2.umist.ac.uk/construction...xp/sfbmdex.htm


... If you have 10,000 lbs of pressure on
the main only a fraction of that force will be utilized to incur lift on the
boom. The vang is not holding down the entire pressure placed on the main.

No, it isn't... but it is holding down 100% of the leach tension, which
is very large. It also takes all the load of the mainsheet when hauled
in tight to go to windward. If it doesn't break when you honk down on an
8:1 purchase, then it should hold at least 8X your honking strength


For using the boom as a lifting device.... you will stress the vang unduly
with a set-up located that far back on the load arm.

???

... It's not designed for
that.

It should be. Anything less would not be safe for sailing IMHO.



I await your rebuttal... :-)

If I give you a re-buttal, then who was the butt in the first place?

Seriously, I'm not saying 'all solid vangs are great for lifting heavy
objects' because many aren't. But then remember Sturgeons Law '90% of
everything is crap' and then tell me why it *shouldn't* be.

Some are. I know that for a fact. And if I had a solid vang that's what
I'd insist on. YMMV

DSK