Subject: [harryproa] Re: 60' Trailerable Proa |
From: Mike Crawford |
Date: 7/27/2010, 2:05 PM |
To: harryproa@yahoogroups.com.au |
Reply-to: harryproa@yahoogroups.com.au |
<< I am certainly not implying any superiority of the Atlantic
design>> I
think that's all, but I'll bring up more, when they hit me. HELP!
Stop the voices. Dennis Dennis,
Hey, no worries even if you are. They are both impressive ways to
have one's cake and eat it too.
Please note that none of this is an argument for Rob's Harryproa
design. I'm just a fan of being as safe, simple, inexpensive, and fast
as possible, and most of Rob's design elements work for what I'd like
to do.
At this point, arguing atlantic-vs-
Perhaps your ideas will infect my brain, and I'll end up pining for
an atlantic rig. Actually, most atlantic proas don't appeal to me, so
it's not the rig that would sway my building plans. I'm sold on the
leeward rig.
What would cause me to consider an atlantic rig is the fact that
you've solved one issue that is close to being a showstopper for me:
how to have a trailerable multihull with an enclosed saloon, where my
wife and daughter can stay warm while I'm out enjoying a nice fall or
spring sail.
Rig now the family debate is between an Etap 32 monohull (the next
boat *must* be unsinkable) and a Harryproa. On July days when it's 80
degrees, my wife and I are both for the proa. But as soon as the
temperature dips down to 70, which means it will be cooler on the
water, My wife is set on the boat with a heated saloon.
Since I'm not willing to spend $350k on a Dragonfly, and wouldn't
want
to deal with a stayed rig even if I did have the extra cash, that puts
us at an impasse. There's no real argument going on, but we're also
not making any decisions either.
---
My current ideal boat would be your design with a leeward rig, even
if that means going to a 10' or 12' trailering width. I'd trail the
boat so little, mostly just once in the spring and once
in the fall, that I wouldn't mind getting the wide load permit.
I would probably go with scissors beams like cat2fold, which would
keep the boat together and vertical while expanding or contracting on
the water. Rafe Francke quoted me $2,500 for a license to his patent
to build a boat, and that's something I'd be willing to pay in this
case. With the scissors beams and a wider collapsed width, the leeward
hull can stay upright and "structural"
Most people seem to be planning on telescoping beams, saying they'll
cost less, and that they will be more than stiff enough. I can't
imagine them
being as stiff as the scissors beams (though they will be lighter),
while also being easy to expand and collapse, but
I'm not going to argue with anyone. I'm sure they'll both work, and
I'd always welcome the chance to be proven wrong by Robert's upcoming
build.
The 8.5' design limit would probably preclude leaving the leeward
hull attached, though. You could still use the scissors beams, but
you'd have to demount the leeward hull to trail the boat.
In any case, it's a beautiful boat. I must confess that the low,
skinny leeward hull is particularly appealing.
- Mike
On 7/26/2010 7:17 PM, Dennis Cox wrote:
From:
Mike Crawford <jmichael@gwi.
To: harryproa@yahoogrou
Sent: Mon, July 26,
2010 5:07:09 PM
Subject: [harryproa]
Re: 60' atlantic proa
That is extremely cool. Thanks for pointing out the video link. You
could probably do this with a purpose-built trailer and a stub mast in
a separate socket (1/3 full mast height, used to lift the primary mast
at its center of gravity) , no crane required.
Now I *really* want to see you build it. I've said many times that i
want the largest trailerable boat I can get, and this would certainly
qualify. Actually, I'd be willing to put up with a 12' width, but
fitting into 8.5' is even more impressive.
I had actually brought up atlantic vs. harryrproa in a post right
before the one you responded to, but for some reason the post didn't
make it. (thus my comment about ignoring my question about how the
boat goes on the trailer).
I'm partial to the harryproa design for the following reasons: a)
more space in the windward hull, b) heeling moment decreases, or
remains the same, as you fly a hull, while heeling moment increases
with the atlantic design, c) stresses are in line with the hull, while
the atlantic has to translate rig stress through the beams to that long
leeward hull, and d) the possibility of popping back up after a
knockdown.
As far as handling the sails, a leeward design might offer more
safety in a schooner configuration (from the tramp), while a single
mast would probably offer safer sail handling with the atlantic (from
the cockpit).
But I'm sure you're familiar with all that. Your design has more
than enough space to deal with masts in the windward hull, and the
taller leeward hull needed for a rig there might get in the way of your
trailering setup. As long as you don't sail on the very edge, there
shouldn't be any issues.
I wouldn't put on a pod for safety as cavalier suggests. If you're
sailing an atlantic proa hard enough to fly a hull, in anything other
than flat water, there's a good chance you'll be going fast enough to
trip over any pod small enough to justify its own weight penalty.
What are you planning for steering and leeway resistance?
- Mike
On 7/26/2010 2:43 PM, Dennis Cox wrote: