On Fri, 30 Jul 2010 11:50:17 -0500, DougC
wrote:

I have made a Freeship model of the hull I am interested in.

page with file link-
http://www.norcom2000.com/users/dcim...oat_makin.html

-or Tiny-
http://tinyurl.com/2g8h8f8

This is not the 100% final version, just a close approximation. The idea
is basically a extra-wide rowboat hull with a very flat bottom. There
will be a flat sealed floor set 6" above the hull bottom on frames
spaced every foot.

This is a inland/fla****er boat only.

Your URL links to a site that provides a ZIP file which expands to be
a FBM file. My system doesn't read fbm files.

I would get it rated for a small motor, 5 HP I think. Not very fast, but
as light & broad as the hull is, it's just not going to be safe going
fast anyway. Other 14" boats seem to be running 20-30 HP regularly. 10
MPH is okay for this, I just need a motor that's "faster than rowing"
while being and "less effort than rowing".


Why do you want to "get it rated" for a motor? Are you going to
manufacture it commercially?

One 14" commercially-made boat I found used 2mm (~.078") for the hull, I
dunno what alloy. I have no idea how thick to go for the floor. I think
the usual sheet the local metals supplier has on hand is 5052.

You can't equate length and skin thickness. You need to first develop
the actual structure of the boat and then decide the force which must
be opposed by the skin. To exaggerate - a boat with no formers or
stringers depending solely on the skin for strength, i.e., monocoque
construction, would require a totally different material then one
that used a "egg crate" type of structure..

-------

,,,,Coincidentally [if you are a USA poster] I cannot find out how to
rate a home-built boat for horsepower on the USCG website. I found the
home-builder's handbook stuff, they go into all the math to find hull
displacement and determine gear and passenger capacity and they have a
table giving weights for engines of increasing sizes,,,,, but they say
nothing about how to decide how much power to hang on a boat. Is there a
formula for this, or is it just--you ask for as much as you want, and
they make the final call?
~

I believe that the question is "why"

Cheers,

Bruce
(bruceinbangkokatgmaildotcom)