[MHml] New Maxi-Tri Banque Populaire

[Dave Culp]

The first time I saw this was on the 60' speed sail boat "Slingshot" in
1978: http://www.dcss.org/speedsl/crossbow.html

I spoke to the designer at length about the boat while in Weymouth (he was a
pro submarine designer!); he designed it with the sailplan further aft, and
the cg aft as well, specifically expecting the rig's forward pitch to bring
it down on its lines at speed. This was a flat water boat, of course, but
shows that designers were thinking about rig pitch, even back then.  FWIW,
the boat did not sail as fast as expected--Crossbow handily beat her--but
the boat had some very interesting bits to her--the proa/trimaran/proa setup
for one (lots of mechanical difficulties, but this idea often rears its
head, never lasts long enough to be optimized); also an early use of planing
main hull (very much like Farrier main hull lines). The boat planed early,
as do Farriers, but many felt the wider sections, versus those of Crossbow,
limited her top speed. The amas carried almost none of her displacement, of
course.

I disagree with you, Paul, regarding "only difference is there is hull where
there would be a spin pole." You make a good point, in flat water, but in
the rough, fining out the hull allows moving small amounts of buoyancy
forward, allowing much finer entry than a long poled boat's necessarily much
"blunter" entry. This long entry is available when it's needed, but stays
unwet when the going is light and wetted surface rules.

Dave

On 12/12/06, Paul Nudd <paulnudd at actionpotential.com.au> wrote:
>
> RTHUTCH at caltex.com.au wrote:
> > Is this really "pushing back" sail plan or building boat where there
> would
> > ordinarily be a spin pole? The boat instead of pole gives access to
> fitting
> > and gives longer waterline, simplified support for tip as no whisker
> wires
> > or bob stay needed. This also explains the "short" floats.
> -----------------------------------------------
> I think you are right Bob.
> Lock Crowther tried the Mast aft solution with the 'Twiggy 31' which was
> still a predominantly mainsail driven boat but with quite a lot of main
> hull in front of the forestay. This maxi BP is nothing like aft mast but
> simply has a nice amount of main hull in front of the forestay.
> Long bowsprits are driven by LOA limitations. If you are limited to 60
> ft LOA then you can extend the loa of the rig with a bowsprit, giving
> more performance for your 60 ft LOA. If you remove the LOA restriction
> you can build a longer main hull and have the same rig and the
> additional benefits as described above.
> What we have here is a 37 metre tri with the appropriate rig for its
> size with a 3 metre bow extension on the main hull in lieu of bowsprit.
> Paul Nudd
>
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