Skin on frame sailboats

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Skin on frame sailboats

Postby lncc » Fri Jun 27, 2008 9:06 am

hoz wrote:Check out Geodesic Boats for plans of all sorts of lightweight SOF boats. http://gaboats.com/. He uses heat shrink aircraft dacron coated with latex paint for covering.

The inventor, Pratt is gone but his widow is carrying on the business.


Wow hoz that sure is a great link. Thanks!

Guys look at this!
Image
10' LOA, 48" beam, WEIGHT = 27lbs!

And is sails too!
Image

The skin is the kind of Dacron used on airplane (crop duster) wings. Is such a material available here? Cloth would suffice but it might be nice if the material were available locally.

For strength I guess they put a diagonal grid of Kevlar fibers across the framework:
Image

I wonder if rattan strands would make a suitable replacement.

For the framework how about stripped bamboo? Stripped meaning as is done when building a kite.
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Postby lncc » Sun Jun 29, 2008 10:17 am

Cybernaught wrote:... I like the 27 lb sailboat pictured. Nice! :D


Glad you like it CN. I have to admit its got my mind racing. I'm thinking what if I re-engineer my CR13 for this construction method. The hull weight would probably go down at least 50% and the boat would plane in the lightest of winds. RTV here we come! Honestly, I got a lot further along and even pulled out my plan set yesterday.

Aside from the prospect of giving the guys a run for their money at the RTV, one idea I like is that with a lighter hull I could put on a bulb keel and add more sail area without making the CR13 into a rodeo horse - tame but fast. My son likes capsizing but may I have set enough PHBYC records in this area already :(. Seriously, why should only race boats have a ballasted keel.

The key issue to my mind now is what to replace the Armid tow with. The Aramid I believe serves the purpose of stiffening the hull by "cross bracing" the structure. At the Geodesic site they sell the stuff at $25 for 300 feet which does not seem to be too expensive. Polymer actually sells Kevlar cloth, which I could unravel, but at P2,500 per square meter I shudder at the thought.

Oh there is one big issue - by mast is 30 lbs ... I'd need a new mast too.
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Postby arvin555 » Sun Jun 29, 2008 12:05 pm

Believe me Lncc if you reduce your boat's weight by 50% you won't need to think about a keel or increasing SA on your boat, it will "fly". Problem is that RTV is sailed as PY, so your rating will be adjusted accordingly, but chances are the adjustment won't be equal to the performance gained at least for the first few races. Until it gets "corrected".

TTFN
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Postby lncc » Sun Jun 29, 2008 12:50 pm

That's true Arvin but I think you'll agree that it is always nice being up front. :)
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