Jerry,
Thanks for going through the detailed analysis and
sharing/recapping. Since harryrproa is the only list I follow, this
is a big help.
It does look as if there could be two lines to adjust the camber.
Since they say "easy camber trim" instead of "automatic camber
trim", this would be my first guess.
However, there's another possibility. It also looks as if the
luff might automatically rotate slightly to windward as the boom is
pulled to windward. That could happen all by itself with a lot of
wind on the sail, and then assisted by manually rotating the mast a
few degrees if the wind is light.
This would explain why the luff moves as the boom moves when they
show the boat at the dock from 34s to 36s. Unless they have a crew
hand out of sight pulling strings while the fellow on camera moves
the boom, but I'd hope they wouldn't be intentionally misleading
like that.
The illustration doesn't look to be too helpful because it appears
to be from the old Omer design that used a cylinder to help maintain
camber. Unless there's a cylinder below decks that helps to rotate
the mast to one side or another, the way the gas-charged cylinder in
a Hoyt jib boom pushes it forward once you get it pat the center
line. That would be neat.
Ahh, speculation.
It looks as if that particular sail would be about 2' high when
filly stowed. In fact, I'd bet that it would be compact enough to
convince me to go with a woven dacron, pentex, or dyneema instead of
mylar -- I question how long mylar will last if it gets that
crinkled up each time you stow or reef the sail.
---
What matters most to me is seeing this sail in action. As
recently as last week I was completely on the fence about whether to
go with a soft wing sail or a normal fully-battened main on a wing
mast with track.
The single-skin sail seemed to be the path of least resistance,
but I also think it would be really nice to:
- Go with a fixed mast instead of a rotating mast -- less
expense and complexity, fewer things to break and maintain. Maybe
add a rotating boom to handle vertical loads, maybe go with the junk
rig system for even more simplicity.
- Skip the sail track and slides.
- Have round bare poles so the boat sails itself less in a
crowded mooring field.
- Gain the efficiency of a wing.
This new Ori sail would do all that. It might not be perfect, but
it works really well, and is nice additional proof of a useful soft
wing sail.
I'd probably have to go with the junk-rigged-wing, though. That
top crossbar adds weight, windage, and complexity I'd like to skip.
I'd be especially worried about shock loading that T joint during
gusts in a lumpy sea -- there's just less stress and less to go
wrong with a straight pole.
But I'm particularly cautious, and thinking about getting stuck
out in a storm far from land, and am not necessarily the target
market.
In any case, I'm very excited to see how the sail works with those
nice flexible battens. I'm convinced that a wing sail is workable.
I think it might even allow me to skip the schooner rig and just go
with a single sail, which would be wonderful for tacking up an
inlet.
- Mike
Mike,
We already had a big discussion on the multihulls list about this but I’ll recap. I did a frame by frame view of the video on my big monitor. They are very careful not to show much of the top inside of the sail. If you look at the still pictures on the site you’ll notice there are four halyards going up to the crossbar. One goes to the front of the sail, one to the back to raise and lower it. The other two go from the deck, to just aft of the mast on the crossbar. From there they run down to the top of the sail, to what I think are blocks on either side of the top of the sail. Those are the dark areas in the video. From the blocks it looks as if they go to the front of the sail where there is probably a prod that moves right or left to adjust the leading edge of the sail. On the bottom of the sail the bottom most rib is a set of two half sections, one from the mast aft and the other from the mast forward. Just below the forward section is another prod that moves the leading edge. So they have control of the leading edge of both the top and bottom of the wing. Then you’ll notice that the intermediate ribs have a pivot point/hinge where the battens are attached. It looks to me that to adjust the camber they move the nose and with the flexible battens the whole sail takes the right shape. Things I wonder about is if it is better to rotate the whole mast as they did, or to make just the crossbar at the top rotate? How high is the stack when the sail is fully down?
Jerry Barth
