'Blind Date' specifications are correct,
though difficult to believe. The materials list, ex sails, freight,
wastage and taxes totals $Aus25,000/$US14,000. Materials lists on new
boats are notoriously difficult to calculate and are invariably low.
Based on any other 15m/50 footer these weights and costs seem ridiculous.
Based on Harrigami (see Harrigami)
they are much easier to believe. (more
about Visionarry design)
'Hurry Up' our Racing Harrigami is in one piece. The demountable
kiri/carbon beams are installed in sockets in each hull. Not super rigid,
but at 6.5m wide it wasn't expected to be. Windward hull (strip planked
kiri/glass) weighs aboiut 50 kgs/120 lbs. It won't be much fun to live
in, but could not be any smaller and meet the rules
The top half of the 15m telescoping mast is built and bends in
static tests exactly as predicted. It is a bit heavier than predicted,
but Rob attributes this to the learning curve. Lower mast halves are
built and the bearings are inserted. There are a bunch of tests to do
to ensure the telescoping will work, but should all be in one piece
soon.
This mast was built using a new technique which Rob has developed. It
results in a mast which is lower cost than an equivalent weight aluminium
spar, and is much stronger and stiffer.
The technique requires very little in the way of moulds or expertise
and uses vacuum pressure to ensure a void free, well compacted laminate
that is not far off what we would expect from heated, pressure moulded
prepreg laminates. It is, however, fairly time consuming. The 7.5m top
mast on Hurry Up took the best part of twenty hours to build. This did
include a fair bit of learning. It is very cheap. Hurry Up's two piece,
unstayed mast weighs about 50 kgs/110 lbs. The material cost is about
$1,500. This is $AUS30/kg $US7.50/ pound (bit difficult to be exact
at this stage due to errors, unfinished rolls and the cost of flying
in the carbon instead of shipping it). Cost would be $14,000 if it was
built using conventional techniques.
'Hurry Up' showing full sail, one reef, and deep reef using the telescopic
mast.
So, although the prognosis is good, there is a fair bit of testing to
do before selling plans for masts. The testing is a 3 stage process.
First, Bruce (harry proa engineer) has stipulated the laminate schedule
to be used and some static tests to perform. Second, the mast will be
tested on Hurry Up in the worst conditions we can find. Third, we are
sponsoring 4 students at the University of Western Australia engineering
deprtment to analyse some samples built using the technique. This is
a long term project under the supervision of Associate Professor Xiazhi
Hu, a very experienced and helpful composites expert.
The rig on Hurry Up is not an Easy Rig. It is an experiment to see if
the gains of a taller mast in light air are worth the increased capsize
moment in heavy air and the extra work and gear needed to make it work.
It is not worth doing in a short handed boat where the EasyRig reigns
supreme. However, the racing rules stipulate 4 crew, so the una rig
was tried. If nothing else, it gives the extra crew something to do.
Making it telescoping complicates the analysis of the buiding technique.
Hopefully, these complications can be allowed for.
New rudder design: Rob reckons he has tried over 20 different
rudders on his various proas. All were a search for the holy grail of
proa rudder design. This would be a rudder that kicks up in both directions
in the event of grounding or hitting something Can be raised or lowered
and still be steered Has no holes below the waterline Can be raked aft
or raised for helm balance Is cheap and easy to build and install The
new rudders look like doing all these things. Testing should happen
on Hurry Up before Xmas.
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