Hi,

I am still a bit hung up on how much of the expense of building a boat
is tied up in the masts. I know that Rob is working on techniques, but
I haven't see him publish anything and I expect that he is still
relying on the builder not being a complete moron and fumblefingers. I
can't afford to make those kind of assumptions <grin>.

Anyway, I have uploaded a really simple idea for building a wing mast
(crude_wingmast.pdf in Files). The idea is to make the central "tube"
just like the crossbeams, out of a flat sheet, folded into a square.
The leading edge could be infused over a PVC septic pipe, and the
trailing edge of the wing would just be 2 more flat panels.

There are several really obvious problems with this, such as a
semicircular leading edge instead of a elliptical edge. Also, the
trailing edge is flat, instead of elliptical. I know this isn't
optimal, but I don't have any way to determining how much it hurts
performance. Is this something that Xfoil can do, for those of you who
have it? It would be great if we could get some numbers out that would
say how much less force the sail would produce.

Another severely non-optimal factor is that the mast would not taper
towards the top. I know it will increase weight aloft, but that seems
of little significance in a multihull which sails basically flat. It
might need to reef earlier, but I could live with that, if the
difference is minimal.

The common thread with all these suggestions is fairly obvious. I know
that there are fields where alot of effort is put into optimization,
but with marginal benefit in the real world. I know that is true with
writing software, and I am hoping that there are people here who are
knowledgeable enough to not just figure out the difference, but who
can also explain how much difference would be apparent in the real
world.

I think that the harryproa concept has hit huge performance benefits
from the basic proa concept, reducing weight and making the hulls so
slim. I wonder how much more optimization we need.

- Gardner