On Fri, 3 Dec 2010 13:13:53 +0000, terryjohnson
wrote:


I am considering to cast myself a planing boat out of marine grade
concrete - I know they use it for sailboats with displacement hulls, but
would it work for a light boat, too?


Err... the correct term to refer to a
"concrete boat" is "ferro-cement" which comes from the way that they
are built., ferro meaning steel or iron.

A ferro boat is built by first framing the hull with steel reinforcing
bar, then covering this form with steel mesh and lastly "stuccoing
over this "armature" with concrete applied largely with a trowel.

You idea of casting a boat, disregarding the weight problem, is that
concrete is hell for strong in compression but not really worth a damn
in tensile or bending strength.

Cheers,

Bruce
(bruceinbangkokatgmaildotcom)