My work has been suffering similarly for quite some time.
Fortunately the affliction comes in spurts, and I can get back to my
normal life in between the episodes.
As you guessed, an una rig is a mast with a big main
and nothing else, though it tends to refer to a shaped windsurfer-type
sail, not just a tall straight one. For more information, scroll to
the bottom of this link:
http://www.transitionrig.com/rigs.htm
An una rig with a traditional boom will require
downward force on the main clew, either with a vang
setup, a very rigid boom/mast joint, or with tension on the sheet.
This is the top una rig shown on the link above. This
has the advantage of putting as much sail area down low as possible.
The lower picture is an una with a wishbone boom, like
a windsurfer. This doesn't have as much sail area down low, but it has
the unique quality of the wishbone boom being perpendicular to the
forces on the sail. If you tighten the boom, the whole sail flattens
out and generates less lift. If you loosen it, the whole sale shapes
into a foil and generates more lift. No additional lines to work or
coordinate. The sail can then be positioned at any angle of attack
without paying attention to mainsheet and vang
tensions to create the proper shape without twist. Lazy jacks can be
added from the boom to the mast to contain the sail as it is dropped.
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@gwi.net>
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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