Nice summary,
You can go a long way in that extra 40 minutes to rig and derig. Much
more than the half to one knot difference the rig could make. For
bigger boats the difficulty in handling the weights of the masts may
reduce the rigging time difference.
regards,
robert
--- In harryproa@yahoogroups.com.au, Mike Crawford <jmichael@g...>
wrote:
>
> <<all this looks as if the schooner rig efficiency is much less
than the
> one of the una rig.>>
>
> That's tough to tell at this point. That second sail obviously
isn't
> contributing a whole lot past 16 knots, but once such a small
> non-planing boat goes past 16 knots, there could be other limits at
play.
>
> The trick would be to get a taller una rig and then see: a)
where the
> boat's top speed lies, and b) how it compares to the schooner in
light
> wind. The schooner's extra sail area, at lower apparent wind
speeds and
> higher apparent wind angles, will probably then register.
>
> The big question would become reefing versus dealing with two
sails.
> A tall una will be great in low winds, but will require more
changes to
> increase and decrease sail area as conditions vary, when compared
to the
> lower center of effort of the schooner. The schooner will require
more
> effort on every tack.
>
> The una rig clearly would require less effort to shunt, and that
means
> a lot. If the boat does have a limit past which it isn't likely to
be
> pushed, it makes a lot of sense to skip the second mast and save
the
> time and effort required to rig it and tend it. When trailering an
> Elementarry, sailing it, and trailering it back home, the effort
savings
> could contribute noticeably to the day's fun.
>
> - Mike
>
>
>
> dominiquebovey wrote:
>
> > Hi,
> > all this looks as if the schooner rig efficiency is much less
than the
> > one of the una rig. My feeling is that the forward sail disturbs
the
> > rear sail to the point the latter could actually be almost only
drag
> > and no propulsion. This assumption could be supported by the fact
the
> > una-rigged proa seems much less constrained in sailing ("flies
over
> > water").
> >
> > I would really be interested to see an easy rig compared to the
una,
> > but I am starting to think it might not be much more efficient
than
> > the una. But hey, in racing even 0.1kn is something. On class C
wing
> > masts you almost always have "deflectors" in the wing mast leading
> > edge, to force the air going faster on the extrados (depression
side)
> > of the wing. In an easyrig the jib plays this role.
> >
> >
> > --- In harryproa@yahoogroups.com.au, "Rob Denney" <proa@i...>
wrote:
> > >
> > > G'day,
> > > Went sailing on Sunday in Elementarry to assess una rigs vs
> > schooners. 15 knots of breeze, solo, with 11 sqm/118 sq' of sail.
> > This is half a Tornado sail area but the sail itself probably less
> > than 75% as effective due to the mast and the set up.
> > >
> > > Simply amazing. It is a different boat. Flies over the water
rather
> > than trying to force it's way through it. Steered itself, the
bows
> > were up upwind and top speed was not a lot different to the
schooner
> > rig (16.4 knots max, vs 16.8 with the schooner in similar
conditions).
> > Followed a Tornado upwind, was pointing as high, but going slower.
> > Quicker than a racing Hobie 16 reaching. Not many other boats
were
> > sailing. Not much sea, but occasional large wakes from
powerboats.
> > Handled with aplomb, although wet if the beam hits the wave top.
> > >
> > > I steered using only the aft rudder which was similar to
steering a
> > conventional boat, the forward location making up for no
daggerboard,
> > the oversize rudder making up for the lack of lever arm.
Shunting
> > was very easy (a nuisance going to leeward to lift and lower the
> > rudders), never got close to getting into irons or caught aback.
> > Downwind, it just got up and went. Occasionally buried the bow,
but
> > did not slow it down. It is now definitely a boat anyone could
sail
> > solo and one which I look forward to teaching my 4 year old
daughter
> > how to sail on. Should also be able to look at the gps while
sailing,
> > rather than only the max speed at the end of the day.
> > >
> > > Interestingly, I only flew a hull once or twice the whole time
(too
> > lazy to get off the windward hull, too amazed by how comparatively
> > easy it all was to bother with pushing the limits), which suggests
> > that the rig is under utilised, something supported by looking at
it.
> > A new wing mast will help this. I was going to increase the una
rig
> > sail area, but think I will go with the same area, but with a wing
> > mast, maybe forward raked to reduce sheet loads. Also building a
> > single rudder setup so I don't have to raise and lower them each
shunt.
> > >
> > > The single rig is quicker to rig and derig; An hour and a half
from
> > arriving at the ramp to sailing, but at least half of this was
one off
> > jobs that needed doing. Also easier to right after a capsize and
4
> > grand cheaper.
> > >
> > > I am not a lot wiser about how long boats should be for a given
sail
> > area, but am pretty certain that it is much longer than they
currently
> > are.
> > >
> > > I think this was not so much a comparison between schooner and
una,
> > more between lots of sail and less, although 2 is definitely
twice the
> > effort of one.
> > >
> > > Apologies for cross posting.
> > >
> > > regards,
> > >
> > > rob
> > >
> >
> >
> >
> >
> >
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