The multimarine L-7 does use pultruded i-beams for its akas. It's a
neat little boat designed to be as fast and inexpensive as possible.
Details at:
http://multimarine.
However, I'd worry about i-beams for the akas on a big proa.
i-beams are great at resisting an up/down bending moment in the same
direction as the main flange of the i-beam, and so may cost less than a
box beam for the same strength.
i-beams are not as good as a box beam in torsion, though, and there
will be torsional stresses on these beams that you won't find in a
trimaran.
You might be able to look at taking two pultruded eglass beams and
joining them in a box with a layer or two of carbon around the outside,
but I'm not sure if that would end up saving any weight or money. Once
you take into account the labor and materials to create a box beam out
of two c-beams, the standard beams as designed and analyzed by fea
might be a better choice.
Unless there are some good pultruded box beams out there...
- Mike
jrwells2007 wrote:
I think that Mike at Multimarine in the States does a small tri using
I beams
--- In harryproa@yahoogroups.com.au , carlos Solanilla
<carlosproacarlos@...> wrote:
>
> I always thought that if the parameters are know for the crossbeams
then you could take those requirments and shop for a
poltrudedfiberglass I Beam that fi these requirements. It should save
time and buy you piece of mind. One day while web surfing I stumble on
a small trimaran using pultruded I beam which made a lot of sense to me
>
> I used to have a link to a vendor who did custom work but when my
computer crashed it got lost
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