--- In harryproa@..., "Todd" <ktsrfer@m...> wrote:
> --- In harryproa@..., "proaconstrictor"
> <proaconstrictor@y...> wrote:
> >
> > The pacific proa isn't generaly highly stable when flying a hull,
> so
> > it isn't going to be any faster for lack of drag. Also, as it
> cants,
> > it looses both stability and sailing efficiency.
>
> I disagree. With numbers and design

Sounds good. and the numbers and designs would be...

you can make the hull stable when
> flying the ama. Maybe not as stable as if both ama and vaka were in
> the water

Yeah, but that was the question...

but stable enough to fly the ama long enough to make a
> difference

It certainly makes a speed difference for the boat that is sialing
along nicely with it's ama out of the water, but if one ramps up the
horsepower, this same boat is going to hit it's pod, while the HP is
going to hardly notice.

. To my limited knowledge drag is everthing less the
> better. Check out Sail november 10 issue 2003 page 68. aw yeah lean
> an mean.
>
> So you have a long lean high p/c high boauyant lee hull and a wide,
> shorter in length, short in performance windward hull vs the
leehull.
> Why doesn't the shorter hull limit the leehull?

Everything limits everything. This is where my you gotta decide
point comes in. Take the Harryproa, what is this, a 40 footer, or a
28 footer? In the HP's case, it make some sense to look at say the
40 footer as an F27 sized boat with a 40' LOA because the
accomodation length, and saiplan are in a hibrid comparison closer to
what that shorter boat would offer, than a longer 40 footer. In that
sense, you have a reasonably low drag main hull, and a very efficient
long hull with a big sled effect to it. It isn't a mater of the
longer hull being slowed down by the shorter one, it is a mater of
that one long hull being an efficient piece of engineering in
comparison to amas of say 26 feet. If what you had was a catamaran
with the numbers of a 40 footer, but just one short fat hull, then
you would have a problem, but the numbers on displacement etc...
don't sing out 40 foot cruising multi, this is a pretty small boat.

Since there are as yet few people who have sailed an HP, it's hard to
know whether the exact proportion of the hulls is perfect. Rob has
said that he doesn't rule out any comaparative hull ratio. I don't
consider the equal length proa to be a different animal, in fact in
an area of lakes, where perhaps big waves are not so prevalent, it
might be more reasonable to trailer a 27 footer with a 27' lee ama.
Maybe it would be possible to make a great Harryproa ith a razor thin
windward hull, basicaly the same as the lee hull, but with the same
kind off accomaodations on it. You would end up with a narrow
walkway, and a wave piecing effect.

One thing that is hard to calc is that as you really press down on
the lee hull, and are ripping along, you have unweighted the WW hull,
how much does such a hull, unweighted drag? Does it ever ballance
out where such a hull really doesn't drag much? Not sure.

>
> Todd
>
>
> >
> > The right approach to the lee Harry hull is to ensure it has
> > sufficient displacement not to drag too much in any operating
> > environment. Which is why it is long, very high PC, high
bouyancy,
> > and fine.
> >
> > When comparing an HP to an equal length HP, the main issue is
what
> > are the numbers. Is it the lee or windward hull on the HP that
is
> > the same length as the Equal length HP. The answer makes a huge
> > difference in the comparability.