From: Robert

To: harryproa@yahoogroups.com.au

Sent: Friday, January 20, 2006 10:20 AM

Subject: [harryproa] Re: sailing Elementarry

For Elementarry , the limit on speed seems to be the forces that bury
the bow: drag on lw hull, height of coe of sail power, fore aft
righting moment. Making fatter or taller bows to improve fore aft
righting moment may not do any good as it increases drag (In fact
Nacra have gone the other way and chopped off the top of their bows
but kept or possibly increased the lower bouyancy); Going longer
means a bigger boat; reducing depth and drag of rudders should do
something; replacing a schooner rig with a una rig will lift coe of
sail power and make it worse, unless through increased efficiency of
the rig there is less drag on the hull and foils in preventing
leeway. Can't see it myself unless you go to wing.
Regards
Robert


--- In harryproa@yahoogroups.com.au, "Rob Denney" <proa@i...> wrote:
>
>
>   G'day,
>
>   Not much difference in speed, although I have no real numbers to
compare as I have not used an Easyrig on Elementarry.  Cost is
probably similar, the easyrig maybe a little cheaper. Ditto ease of
construction.  I would be quite happy cruising with either.  Suspect
neither is as fast as a wingmasted una rig, which is the next one to
try..   
>   I found it was easiest to drop the jib and sail with the main
only when I needed to reef. This would not work on the schooner where
the aft sail would be reefed first.  It is pretty easy to sail the
schooner on the front sail, very difficult on the rear one.
>
>   Polycore butt joins with bog or nothing.  It will require a lot
of resin to fill the gap if infusing so some form of filling is
probably required.
>
>   Compounding Polycore may be possible with an iron, or with
slits.  Need to do some tests to see. 
>
>   Regards,
>
>   Rob
>
>   I must admit the schooner rig appeals to me as well, though when
I pushed Rob
>   he seemed to favour the easyrig (Harry) and after all it's his
baby and he
>   probably has more time sailing both rigs than all of us. What
happens to the
>   balance of the easy rig with two reefs, or if you are running
with the main
>   down in heavy air?
>   Would really appreciate a detailed comparison of the two with a
few numbers
>   thrown in (speed, cost, ease of construction).
>   Another question about the poly-core, how do you do butt joins?
how do you
>   form compound shapes? Sorry if this makes me sound like a Wally
who knows
>   nothing but it's big project for me.
>   Cheers
>   David
>
>   ------ Original Message ------
>   Received: Tue, 17 Jan 2006 09:26:03 AM MST
>   From: "Robert" <cateran1949@y...>
>   To: harryproa@yahoogroups.com.au
>   Subject: [harryproa] Re: sailing Elementarry
>
>   For cruising I still prefer the schooner rig. Yes extra sheets
and
>   sheet loads but you can bring sails closer to deck as you don't
need
>   clearance for the forward part of the boom and you can couple the
>   sheets and use a small winch. Overall significantly lower c of e
of
>   rig and therefore less capsizing moment for given sail area. Also
for
>   shallow water sailing there is some directional control with just
the
>   sails. Whether to go for a wingmast or a round mast with pocket
luff,
>   I am ambivalent. Wing mast probably more efficient but I like
>   simplicity and reliability of pocket luff, Wharrams are pretty
happy
>   with them (OK I know that is not necessarily an argument about
how
>   well they sail but it is an argument over there reliability) I am
>   even tempted to go for a Wharram type gaff rig only using a
nicely
>   curved carbon tube for the top spar. I like the idea of the
unstayed
>   wishbone boom
>
>   Down wind for cruising it has to be a kite. Lifting bows instead
od
>   depressing them. On a long downhill section put all other sails
away
>   and relax unless you want to get that little bit more out of the
kite
>   by figure of eight flying. No worries about leaping off the top
of
>   the wave and plowing into the back of the next one, stalling and
>   pitchpoling as you haven't let go of the screecher in time and
the
>   apparant wind has doubled. With a kite your bows stay up and if
you
>   do stall into the back of the next wave the kite will pull you up
>   insead of over --- In harryproa@yahoogroups.com.au, Mike Crawford
>   <jmichael@g...> wrote:
>   >
>   >
>   >   For going fast, I'm more a fan of Rob's schooner rig than the
>   easyrig.
>   >
>   >   This is partially because there are no concerns about
forestay
>   > tensions, and fewer concerns about rig stiffness, and mostly
>   because it
>   > provides for more sail area, with better foil shapes, and a
lower
>   center
>   > of effort.  When tacking downwind in light wind, two battened
foil
>   > shapes are going to generate more lift than a main and jib, and
>   when
>   > running the schooner could present quite a wing-on-wing profile.
>   >
>   >   The schooner rig will require more winch work than an
easyrig,
>   but
>   > only when lazy sailing.  if you want to be competitive, you'd
need
>   all
>   > sorts of additional strings on an easyrig anyway.  I'd rather
go
>   with a
>   > pair of extra-tall mainsails for light wind, and reef them in
>   normal
>   > wind, than to try to stiffen an easyrig with running stays and
>   attempt
>   > to fasten additional headsails.
>   >
>   > ---
>   >
>   >   Speaking of rig stiffness, I do feel the need to weigh in on
the
>   > comments about Rare Bird's rig.  Yes, it's pretty flexible. 
>   However, as
>   > the owner of a lightweight 27' cat, which can only be righted
by
>   another
>   > boat if capsized, I can appreciate a rig that will allow some
of
>   the
>   > gust energy to pass by the boat.  Going over on a beach cat or
>   > Elementarry is wet and inconvenient.  Going over on a 9+ meter
boat
>   is
>   > tremendously uncool.
>   >
>   >   If you've got everything right on the edge, with the windward
>   hull
>   > just skimming the water, it takes *very* little extra gust
energy
>   to
>   > suddenly whip the boat over.  The only solution is to be
lightning
>   quick
>   > with the mainsheet, but that's a tall order if you're going to
be
>   doing
>   > it for more than ten minutes at a time.  Flying a hull is great
>   fun, but
>   > any look at the Stiletto nationals will turn up some boats that
>   didn't
>   > hold that fine balance in a gust.  Even the skippers of the
>   Reynolds 33
>   > lose it now and then.
>   >
>   >   When cruising, going past this edge is entirely
unacceptable. 
>   It's
>   > much better to have a flexible rig, with the addition of
perhaps an
>   > outleader kite, than to risk gust-induced capsize (fool-induced
>   capsize,
>   > of course, is rig-independent).
>   >
>   >   When racing, though, there's still something to be said about
a
>   boat
>   > that can handle the gusts.  Let's say you can fly a hull with
40 sq
>   m of
>   > canvas with a stayed rig, and 50 to 60 sq m of canvas with a
more
>   > flexible rig.  The flexible rig provides two advantages. 
First, in
>   a
>   > gust, the flexible rig will either allow you to keep sailing
>   without
>   > adjustments, or give you lots of time to adjust, while the
stayed
>   rig
>   > will require quick reflexes in order to avoid a capsize. 
Second,
>   those
>   > extra 10 to 20  sq m of canvas will come into play nicely in
the
>   lulls,
>   > do so automatically, while the stayed rig will need to either
>   unreef or 
>   > hoist an extra sail to keep up.
>   >
>   >   Supporters of a stayed rig will point out that the extra
canvas
>   will
>   > create extra drag, so in theory the stiffer rig will beat the
>   flexible
>   > rig in some conditions.  This is true.  But a capsized boat
>   eliminates
>   > all rig advantages.  Besides, we don't all sail in exactly 15
knots
>   of
>   > trade winds, and changing wind conditions will likely favor the
>   extra
>   > sail area and self-adjusting nature of the flexible rig.
>   >
>   > ---
>   >
>   >   The one change I would make would be to go with an unstayed
>   wishbone
>   > rig like they have on the Wyliecats.
>   >
>   >      http://www.wyliecat.com/info/wishbone_rig.html
>   >
>   >   One adjustment line automatically handles sail shape, leech
>   tension,
>   > and mast bend, with very little stress on the boom.  Sail
shaping
>   is
>   > very quickly done, the boom creates its own lazy jack pocket
when
>   taking
>   > the sails down, and a reduction in heeling moment can be
achieved
>   either
>   > by reefing, flattening, or both, allowing for some quick sail
>   > adjustments for a minimal amount of time and effort.
>   >
>   >   However, I've never sailed a Wyliecat, so I can't speak from
>   > experience.  I just love the idea of it.
>   >
>   >        - Mike
>   >
>   >
>   >
>   > dominiquebovey wrote:
>   >
>   > > Hi,
>   > >
>   > > Boats as light and canvassed as HP's mostly sail "close-
hauled"
>   due to
>   > > their high speed, so they need a rather flat sail profile.
But to
>   > > start you need a hollow profile, so the sail should be
tunable
>   quickly.
>   > >
>   > > I would see a 8.5m proa (maximum of M2 class) for 3 crew
(minimum
>   > > number for racing on Lake Geneva), with easyrig, around 30-
40m2
>   sail.
>   > > I am persuaded the easyrig is OK for racing, provided it is
stiff.
>   > >
>   > > One of the crew would be adjusting the sail permanently
(making it
>   > > hollower in the lulls, flattening it when speed increases).
>   Another
>   > > crew would be running up/down the tramp to keep the LW hull
just
>   above
>   > > the water, and the 3rd one steering.
>   > > And all crew could be going on trapezes when needed. So you
need
>   > > running sidestays which can be attached to several selectable
>   points
>   > > on the WW hull or on the beams.
>   > > To go on trapeze, you unhook them off the boat, and hook them
on
>   your
>   > > trapeze pants/harness whatever-the-word-is.
>   > > Naturally the rig must be self supported without the runners,
for
>   easy
>   > > cruising.
>   > >
>   > > I know it is quite a new boat, something between Harrigami
and EL,
>   > > with more displacement. The Elementarry lw "sinks" about 1cm
for
>   15kg,
>   > > for the 8.5m the figure should be 20-25kg, so a less fine lw
hull.
>   > > The Elementarry is unfortunately a little too light for 3
racing
>   crew
>   > > I am afraid, as we discussed last year.
>   > >
>   > > Regards
>   > > Dom
>   > >
>   > >
>   > > --- In harryproa@yahoogroups.com.au, "Rudolf vd Brug"
>   <rpvdb@f...> wrote:
>   > > >
>   > > > Hi,
>   > > >
>   > > > Possibly the difference in sheeting in between you and the
>   Tornado
>   > > lies in the fact that they where flying a spinnaker.
>   > > > That sail is so much fuller in shape it would redirect the
wind
>   > > passing it much more than a flatter sail (or no sail at all)
>   would.
>   > > >
>   > > > Some time ago I read an interesting article on a una rigged
mono
>   > > with a wing mast. It was designed not to fly downwind extra's.
>   > > > The owner did have a gennaker but it only gave him one knot
of
>   extra
>   > > boat speed. It was concluded the tighter sheeting angle of
the
>   main
>   > > might be responsible for this. The gennaker would generate so
much
>   > > disturbance of the air passing at the leeward side it doesn't
>   attach
>   > > to the main any more. Therefore the main doesn't generate
lift as
>   it
>   > > does whith no head sail in front and is only  producing drag
which
>   > > helps downwind but not as much as lift would.
>   > > >   ----- Original Message -----
>   > > >   From: Rob Denney
>   > > >   To: harryproa@yahoogroups.com.au
>   > > >   Sent: Monday, January 16, 2006 2:19 PM
>   > > >   Subject: Re: [harryproa] Re: sailing Elementarry
>   > > >
>   > > >
>   > > >   G'day,
>   > > >
>   > > >   Not sure the kite would have helped much as the apparent
was
>   well
>   > > forward of the beam.  Still intend to try it because they are
such
>   > > great fun.  Interestingly, the Tornado was strapped in hard,
>   traveller
>   > > on the centreline, whereas i was quite eased on the same
point of
>   sail
>   > > and at the same speed.   Lots to learn...
>   > > >
>   > >
>   > >
>   > >
>   > >
>   > >
>   > >
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