Well, if that's the case, it's a good example of what Winston
Churchill said about being divided by a common language and an apology
(from this end) is in order.

I've encountered so much confusion over the years on this point, (even
from Coast Guard officers with naval architectural degrees engaged in
writing regulations) that I'm probably primed to expect it.

Since we have managed to so thoroughly confuse each other, I'm sure
almost everyone else is lost as well. For their benefit and not to
talk down to you:

Let's look at the simplest case, a catboat with an un-stayed mast. The
hull and ballast are a given and you now want to figure out how bit to
make the mast. You determine the maximum righting moment which will be
in the 35 - 45 degree range for this kind of boat. The mast is a
simple lever and maximum material stress will be at the deck. The
bending moment will exactly equal the righting moment. Once you know
the material properties, it's a quick calculation to determine the
required diameter, with a proper safety factor applied.

Now, you decide your catboat is a little slow so you decide to double
the sail area. Do you need to make the mast bigger? No. The righting
moment, which limits the force on the mast will be the same. The only
difference is that the boat can be heeled to any particular angle in
much less wind. The force on the mast will be the same at any
particular heel angle as it was before the sail increase.

Actually, because you have added the weight of longer mast, boom, and
gaff, as well as more sail material, the center of gravity will be
slightly higher. This reduces the righting moment. This is within the
fuzzy factor of the calculations as used in the real world but, if you
were to compulsively design to exact loads, stresses, and safety
factors, you would find that the boat with the larger sail plan could
paradoxically have a slightly smaller mast.

--

Roger Long



"DSK" wrote in message
.. .
Roger Long wrote:
Nope, Doug. That statement shows that you are still not getting
it.


Bull****, I've said the SAME THING that you're saying. Look it up.
Maybe you're having a bad morning and just need to feel superior?



Think it through some more. I know from your other posts that you
are smart enough to get the light to go on.


Thanks a lot.

DSK