That wharram rig is a funky thing, isn't it? I don't
know whether to like it or be scared by it. It has been well tested,
though. There are a lot of cats out there with a lot of miles on that
rig, and many with low-tech materials for their spars. Few people
would argue that these rigs haven't stood the test of time.
To be honest, I'm a lazy, tech-head, safety freak. Thus, I'd go for
a wing mast with a fully-battened main sail either on cars or on an
efficient slide system like the Tides marine system.
The tech-head in me would choose a Pentex sail because
it's a nice compromise between a fragile high-modulus sail and a sturdy
good old Dacron sail, and has the same UV resistance as
Dacron as well. Kevlar, carbon, and such look great, and perform well,
but they're fragile when bent or flogged, and UV light just kills most
of the high-tech materials. The safety freak would want to be able to
put several reef points in the sail, and get it up and down easily
without messing with the luff. The lazy part of me wouldn't want to
put the sails away at the end of the day, and would just want to flake
them and zip them up instead.
I don't see stiff/mylar sails jiffy-reefing with a pocket luff, and
I'm not sure I'd trust a zippered luff over time. I'd also be
hesitant, or remove and stow a pocket luff sail (especially in big
weather). Thus, a battened sail with a car/slide system.
I'd love to see someone try a wharram rig, though. I'm
not sure you could come up with a simpler, more efficient design, for
less expense. He is a master of designing for the criteria he has
chosen. He's a good reminder of what's important whenever one starts
to consider plumbed toilets with heated seats.
I have no idea about proportion of sail area -- that's beyond my
knowledge. I'd probably go with less rather than more, if only to have
smaller poles up if a gale comes through.
- Mike
Robert wrote:
My sentiments also. The finer points are the shape of the sail. Do we
go the way of the windsurfer with a square top with batten
arrangements akin to a sprit rig like the Elementarry Rob is sailing
or a thinner tip like Elementarry 1. Do we go pocket luff or wing
mast. If wing mast, what proportion of sail area. According to Tom
Speer you go low or high but not in between. For racing it matters
for getting the last bit out of the rig but for cruising reliability
is probably the greatest concern as they all work. So what is the
most reliale combo? Much of this depends on quality of construction
and I suspect that this may be the dominant factor, but for me at the
moment I am vacillating between a Wharram type rig with an
elliptically curved gaff and a large area wingmast.
Robert
snip
> Many people will argue for either design. It all depends upon
what
> your priorities are. For that matter, every rig mentioned so far
in the
> debate is a good choice, especially the easyrig (which offers a
very
> rare combination of performance and ease of use)..
>
> My personal priorities are as follows: the best possible
performance,
> for a given height limitation, with the fewest strings to pull,
and
the
> easiest way to dump wind quickly, while being generally
forgiving.
A
> schooner wishbone rig is not the absolute fastest rig, nor the
absolute
> easiest to shunt. But it does come close to both, which is why I
like
> it. Change the priorities, though, and the best rig will also
change.
>
> - Mike
>
>
>
> David Howie wrote:
>
> >
> > Question : in the Harry sized boat will all the components
fit in
a
> > container
> > with the easy rig? with the Schooner?
> > Anybody like to clarify what Rob is wanting to try when he
says
una
> > rig next.
> > Is it a single mast with a big main and nothing else?
> > By the way these boats are ruining my worklife, I spend all
day
> > building it in
> > my head and no work gets done.
> > Personal preference is still the schooner with wishbone, but
I'm
a
> > long way
> > from having to commit and like the debate, For me Rob could
turn
me to the
> > easyrig if it were significantly cheaper, again one of the
attractions of
> > Harry is simple/cheap. I can't see the point in making it more
> > complex/expensive than is absolutely necessary.
> > As an aside, the local multi fleet is booming with a new 8.5
m
box rule. I
> > won't be doing it (I'm a cruiser now) but it would be
interesting
to
> > see if a
> > proa could fit in their box then blow them all out of the
water.
> >
> >
> >
> > ------ Original Message ------
> > Received: Fri, 20 Jan 2006 08:51:07 AM MST
> > From: "Mike Crawford" <jmichael@g...>
> > To: harryproa@yahoogroups.com.au
> > Subject: [harryproa] Re: sailing Elementarry
> >
> >
> > You make good points with respect to stays and headsails.
However,
> > one could also make the case that technological developments
in
the
> > past fifteen years have made stays and headsails less
important
than
> > they used to be.
> >
> > Arguments for a wishbone boom, unstayed, wingmasted una rig
(in
> > either a single or schooner setup):
> >
> > - It's common for boats competing for the speed record to
lack a
> > headsail, and instead use a variation of an unstayed,
wingmasted,
> > shaped main.
> >
> > - The speed record current is owned by a windsurfer using a
wishbone
> > una rig. Granted, Maynard uses a planing board the size of a
large
> > spoon, but he's still using an una rig.
> >
> > - A lower speeds, Wyliecat boats (catboats that use a single
> > wishbone-boomed una rig) have beaten larger boats upwind,
when
many
> > people would argue that a headsail will really help.
> >
> > - The una rig, especially if nicely tensioned, presents a
very
> > efficient swept back profile that works well without a
headsail.
> >
> > - Stays generate a surprising amount of drag without
contributing
> > anything to forward motion. While a portion of a flexble
unstayed rig
> > will also generate drag when the rig flexes leeward, it will
pop
right
> > back into generating lift once a gust passes.
> >
> > - The wishbone una rig is particularly adept at generating
lift, and
> > should require relatively light winch loads unless running.
With
the
> > sail being self-vanging, the only load on the mainsheet is
that
which
> > is required to pull the sail just past the point where it
luffs.
> >
> > - With only a boom tensioner and a mainsheet, the wishbone
una
> > requires less time and effort to achieve optimal sail shape.
Unless
> > you have a full crew to pull strings all the time, the
simpler
design
> > is likely to enhance speed over the course of a race.
> >
> > - The ability to fly the windward hull is actually much more
> > critical to reducing overall drag than extra sail area or
stays.
But
> > keeping that hull airborne, or just skimming the water, is a
delicate
> > balancing act. In this scenario, you're much more likely to
be
able
> > to hold that balance with a rig that can absorb gusts than
with a
rig
> > that doesn't give at all.
> >
> > - The lower center of effort on a schooner una rig, as
compared
to a
> > taller easyrig, will likely allow it to generate more lift
for the
> > same heeling moment. Given that both boats use two sails,
and a
> > stayed easyrig will have some additional drag of its own, the
lift to
> > drag ratio of the schooner rig will probably be equivalent or
better.
> >
> > ---
> >
> > With that said, I do love the easy rig -- it's hard to
dislike
a rig
> > that's so darn easy to sail.
> >
> > It's just that any boat in my future plans needs to fit
under
65'
> > bridges, and a 64' easy rig on a boat the size of the
visionarry
isn't
> > going to give me the light wind performace I'd like. Thus,
I've
> > adopted a schooner rig with wishbone-boomed mains as my new
dream, and
> > have in the process become quite a fan of the una rig.
> >
> >
> > - Mike
> >
> >
> >
> > --- In harryproa@yahoogroups.com.au, "dominiquebovey"
> > <dominiquebovey@y...> wrote:
> > >
> > > Hi,
> > > I agree with the safety associated with a flexible rig,
for
cruising.
> > > An easyrig without lateral support just would do it. Or
a
schooner
> > > rig with unstayed masts.
> > > But I feel this is not adapted to racing. To go fast,
you need
> > > "finesse" (I think it is said also in english, isn't
it?). It
is the
> > > ratio of the perpendicular aero force to the planar
force of a
> > > sail/wing/foil.
> > > Or you need lots of unstayed sail area to compensate for
the
relative
> > > inefficiency of such a rig, which increases weight and
drag too.
> > >
> > > And look at the C-class cats with their wing rigs, they
easily
sail 3x
> > > the speed of windm 8whern they do ot break down.
> > >
> > > And there is the "foil" effect associated with the jib
on the
leading
> > > edge of the mainsail. It accelerates the airflux on the
lw side
of the
> > > mainsail and increases the propulsive force. And it
balances
the rig
> > > with regards to the efforts to do winching...
> > >
> > > So for me the rig I would consider:
> > > - easyrig
> > > - boom and balstron are articulated separately
> > > - fore vang to be able to stiffen the forestay and aft
vang to
flatten
> > > the main
> > > - lateral running stays, hookable on several points on
the LW
hull
> > > (one must be able to sail the boat safely without them)
> > > - thick mainsail: a "double cloth" sail with soft foam
battens,
going
> > > on two tracks on the mast
> > >
> > > Hope to be able to try this one time...
> > > Dom
> > >
> > > --- In harryproa@yahoogroups.com.au, "Robert"
<cateran1949@y...> wrote:
> > > >
> > > > 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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