Subject: [harryproa] First building quote for the 60' Seabattical charter proa
From: "Rob Denney" <>
Date: 4/30/2008, 11:05 AM


Got the first quote in for the build of the Seabattical charter proa.
Ballotta in Peru will build the two hulls, decks and beams, with
bulkheads and floors, all LPU painted and joined together for $96,000
(all prices US dollars). Ballotta make some of the lowest cost
quality cats in the world. Their 14m/46' cat to the same stage is
$135,000, their 11.5m/39' cat is $99,000.

Materials were priced from the USA and were expensive compared to
buying and shipping them from Australia. A saving of $10,000 for the
foam option, $16,000 for Polycore, plus whatever time and material
savings are available from the new build system (see below).

The proa will be easier than the cat to fit out as the windward hull
is all on one level and flat. It will be built on the workshop floor,
then lifted and bonded to the hull. However, it has 4 double cabins
with ensuites, compared to 3 in the cat, so the end result will
probably be similar. The 39' cat ready to to sail costs $275,000, the
46'ter $350,000. The 18m/60' proa with the same fit out, (see but a lot more space and
performance, will be somewhere between them.

Of particular interest is the 46' cat's stayed alloy rig cost of
$52,000. We expect to beat this price with 15% more sail area in an
unstayed schooner rig. A quote for the complete boat will be
available when I finish the drawings, at which stage I will also be
looking for feedback on layout etc from list members. Construction
should start later this year.

The 2.4m/8' long quarter scale model of one half of the charter proa
lee hull is completed. The system worked a treat. Took me 90 minutes
to mark out (2 measurements every 250mm/10" on the model) and glass
each side, and another 30 minutes to join them along the keel line.
The gunwhales were then lifted to near vertical and the bows squeezed
together. The below water shape was close to what I had drawn, but
the bilges were slacker (more Vee'd). As expected, it had 20mm/three
quarters of an inch of negative rocker 600mm/24" back from the bow,
tapering to nothing in the middle.

I rested 25 kgs/55 lbs across the gunwhales above the negative rocker
and left it overnight. Next morning, the rocker was straight, the
bilges more rounded and when I laid the panels down flat, they were
noticably compounded. Glassed the inside in under an hour, then
flipped it and glassed the outside in 40 minutes. Profiled the bow
and cut the sheer and it was essentially done. It is typically
rough, the full size hull will need some supporting (I just sat it on
he floor) but fair. The section shapes are very flat U sections (no
floors required) and close to what I had drawn, no reason to believe
that anything between this and a V could not be achieved. No doubt
that Polycore (and presumably foam) can be compounded quickly and
accurately for rockerless hulls with vertical stems. The Polycore
soaked up 200 gsm of resin per side, a little less than H80 foam
(250gsm), but with a much stronger bond. Photos when I find the
cable for the camera.

Next time I will taper the keel joining glass towards the bow to
avoid the hard knuckle I ended up with. If a polystyrene nose piece
was included, which I think is an excellent idea, then the shape for
the last 200mms or so (which is where any mistakes show up) would not
be a worry.

The full size panels will be done on a vacuum table. Maybe infused,
maybe not as I think it will be quicker overall to bag it twice and
have a mould finish on both sides of the panels.



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