On Sat, 30 Apr 2005 12:46:29 GMT, Ookie Wonderslug
wrote:

I was going to build a jon boat that has a hull like your boats. It's
good to see my ideas validated in a way. I built a scale model and
tested it in my pool and a creek and ended up skeptical about it's
benefits. To me it wasn't worth the extra trouble for dubious
results.

I wanted it to ride up on the outriggers at plane so there would be
almost no boat in the water. Instead the rear is still in the water
and the outriggers just dig in deeper causing even more drag. I think
maybe I will build another model that has wider outriggers and see
what that does.

Unfortunately my best testing area was the outflow from draining my
pool. That's 18,000+ gallons that I ain't going to flush down the
creek again this year. I will have to find another place where I can
find high flow water in a small place.

I guess there are some design considerations for the shape of the amas
(or whatever you call the "pontoons" on a catamaran). The other thing
I would consider is that flowing water may be turbulent and do things
to models that still water would not. One builder I know uses a rig
on his boat to float the model to port, and then powers up his boat.
It took him a while to get the harness right so it wasn't influencing
the model. IIRC, there was some pretty complicated math (at least
for me) to determine what 2 knots was to a 1/4 model. But it gave him
some good information for proceeding (he designed a 26' cabin cruiser
that way).

Don't give up on your idea. The main advantage I can see with the
catamaran style hull is the reduction in wetted surface, which for a
jon boat might be significant when trying to push it with an electric
trolling motor or by oars. You should contact Yoav on the Forum at
http://www.messing-about.com/forum/viewforum.php?f=3 Its an
opportunity to leverage off his experiments doing the same thing and
refine your design.
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