BoatBanter.com - Geodesic Airolite Boat with a twist

Snowman,

Having built 4 or 5 of Platt Monforts ultra light canoes, I have a few
observations:

The concept of Kevlar wrapped foam ribs would probably be do-able, but
I guess I'm wondering what you hope to gain. Are you trying to make it
stronger? lighter? I'm wondering, how much weight can you expect to
save on a 14 pound boat? If the only reason is to avoid the heartbreak
of broken ribs during construction, it hardly seems worth the bother.

As for bending the ribs, I'll share my secret recipie. First, you must
realize that every wood bending method will likely result in some
breakage - the question is - can the number of ribs broken during the
bending process be kept to an acceptable limit? I always make 3 or 4
extra ribs for a 12 ft canoe which requires 16 ribs, total. Sometimes
I'll need one or two of my extras, but I've never needed more than
that.

Whatever wood you use, it will have to be selected for straight grain
- very little or no run out. I have had very good success with
SASSAFRASS (that's the secret ingredient). I know this is not a
standard item at Home Depot, but there are two lumber dealers in my
hometown of Springfield, Missouri where I can buy decent sassafrass
boards. Find out where your local cabinet makers buy their lumber -
sometimes it's sold as a substitute for ash (you can make a positive
ID by the smell). If you live in the southeastern US, inquire at small
local lumber mills.

Sassafrass is lighter than most hard woods, though a tad heavier than
the soft woods suggested by Montfort. It's an excellent wood for boats
- weather resistent, glues and finishes well, easily worked with hand
tools, and bends beautifully. At first I steamed my ribs in a PVC pipe
rigged up to a metal gas can (NEW - NOT USED!) on a Colman stove, but
I discovered this is unnecessary. Now I just run a few inches of hot
water in the bath tub and submerge them for a few hours before
bending. If it's a really tight bend, I might put a presoaked rib in
my PVC pipe, now capped on one end, and pour a teakettle of boiling
water over it for a few minutes just before bending.

Good luck,
GW

(Snowman) wrote in message . com...
I'm looking at building a Geodesic Airolite Boat, (see www.gaboats.com
by Platt Monfort) but I'm considering an interesting idea and I'm
wondering what you all might think. Instead of using wood strips to
form the geodesic structure I am thinking about using foam strips
wrapped in Kevlar tape and epoxy.

I have been reading about the construction of these boats and found
that some people have trouble with bending the ribs to shape without
breaking, (and this is with better quality wood that I am able to
source). I'm thinking I can bend foam cores easily to shape and then
once assembled in a frame start wrapping it all in Kevlar tape,
forming a makeshift Kevlar tube frame.

I'm still considering using wood for the stringers and gunwales as I
can form those with little or no problem. Having the stringers and
gunwales constructed out of wood would also make forming the foam ribs
much easier as it would give me something solid to work the foam
inside.

-Does anyone foresee a problem with pursuing this type of
construction?
-How will Kevlar wrapped foam compare to the equivalent
cross-sectional wood piece in strength?

Thanks
Jordan Richardson