Hi,
James Brett here.
Doug, I will take that as a compliment. My proa is far from a piece of crap. In fact it's about the only proa around these parts which can sail any reasonable distance without breaking or running into some kind of trouble.
As far as rigs go, the junk rig is by far my favourite, and I have sailed with a huge different variety of rigs. Every time I sail with the junk rig I come back completely amazed and stoked with its performance.
Having the sail pressed against the mast really has no noticeable effect on performance, as the sail kind of fairs in with the mast to create a fairly smooth curve anyway. Maybe if you tested it in a wind tunnel you could detect a difference in performance between tacks, but in the real world its not worth worrying about. I have got rid of the wrinkles and excessive twist that my sail used to have by adding a 4:1 downhaul system. The boat now performs just as well to windard as the vast majority of sloop rigged boats.
For most modern proas, the only way to balance the helm properly is to have some sail area forward of the mast (which is why all the una-rigged proas I have seen have had steering problems) and the junk rig is a nice easy way to do that.
Regards,
James Brett
--- In harryproa@yahoogroups.com.au, Doug Haines <doha720@...> wrote:
>
> For the unbelievers, I might say that the thing looks like a pile of crap - but somehow seems to go alright (James Brett's NZ proa on youtube) and get's favourable comments. How can the sail have good curving when it has to go on one side of the mast - which looks ok one one tack/shunt, but then it pushes into the mast and must make a huge kink in sail shape when on your other tack(shunt)? The battens would be pushed up hard against the mast (like sail against spreaders on normal boat). The tack with the wind cxominjg from ......need drawing. Wondering if we could infiltrate Sailing Anarchy, just so as to use more photo uploading things DOug
>
> --- On Fri, 27/5/11, Jerry Barth <shredderf16@...> wrote:
>
> From: Jerry Barth <shredderf16@...>
> Subject: RE: [harryproa] Re: Swing-wing rig
> To: harryproa@yahoogroups.com.au
> Date: Friday, 27 May, 2011, 2:18
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> I’m thinking about the junk rigged
> soft wing for a biplane cat project I’ll start when I get done with the
> wife’s new bathroom (couple of years, at least). I’ve been
> thinking of ways to control the trailing edge of the sail without having to go
> to a jungle of Chinese style sheets. Among the things I’ve thought
> of is connecting four or five of the wishbones (so maybe three sections of five
> on a 35’ tall sail) at the trailing edge with say an inflatable
> tube that could be deflated to allow lowering the sail. I guess you could
> also use some kind of rigid tube (carbon, pvc etc) if you tapered the sail
> enough to allow the tube from the section below to extend above the lowest
> wishbone of the next upper section when the sail is dropped. In any case,
> the idea is that instead of 10-15 sheets you end up with three or so each
> controlling a section of five wishbones. The next thing is how to control
> camber of the sail from the hinged tail of the wishbones. I think what
> might work is putting pneumatic actuators such as are used by pig farmers (they’re
> stainless, check out Farmtec.com) mounted on the hinge area of the lowest
> wishbone in each section. The last thing I thought of was of how to keep
> the three sheets you have left from becoming a nice spider web for you to walk
> into each time you go forward. Since in a junk rig the sheet loads are
> fairly low, maybe they could be mounted on a “tower” on top of the
> cabin top, at least high enough to get the lowest one just above head
> level. These are all just thoughts I’ve had over the last six
> months or so, no actual drawings or tests. I do think the junk soft wing
> is the way to go, I’d just like a little neater setup. A last
> observation is that 3/8 inch diameter fiberglass fence posts (used here for
> electric fencing) might make some good wishbone rib material. Here’s
> the link:
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> http://www.tractorsupply.com/electric-fencing/electric-fence-step-in-posts/sun-guard-ii-fiberglass-post-3600980
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> Thanks,
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> Jerry Barth
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> From: harryproa@yahoogroups.com.au [mailto: harryproa@yahoogroups.com.au ] On Behalf Of Mike Crawford
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> Sent: Thursday, May 26, 2011 6:28
> AM
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> To: harryproa@yahoogroups.com.au
>
> Subject: [harryproa] Re:
> Swing-wing rig
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> Ben,
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> While both the Omer and Swing-Wing have similar shapes on the outside
> (with Omer looking a bit better, actually), there are some notable differences
> in the implementation, both in terms of design complexity and sailing
> complexity:
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> - Three panels. Omer
> uses three sail panels: forward, aft port, and aft starboard. You can see
> them in this image with the sail stowed: http://www.omerwingsail.com/lib/8887033.jpg
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> - Reefing. Because
> of this three-panel design, reefing requires hauling down and tensioning three
> separate sections. That'is a lot more time-consuming than reefing a junk
> rig, where you let off a halyard, allow the weight of the wishbones to drop the
> sail, cleat the halyard, and tug the downhaul. Having read Ann Hill's
> description of her ability to single-handedly raise and reef the junk rig sails
> on Badger, even in a storm, I find this most impressive.
>
>
>
> - Hardware. The
> three sail panels require four sail tracks, with the cars to go with them, and
> the structure required to support those tracks out there away from the mast, as
> well as the battens/frames shaping the sail. The swing-wing requires just
> a mast and the wishbones. Much less to build and take care of. The
> wishbones could be wood, glass, carbon, whatever. And while they may
> eventually fail or rot, you could patch them up anywhere in the world with
> local materials. Try that with battcars...
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> - Piston-controlled.
> Omer uses an electric or hydraulic piston to adjust the boom/sail angle on
> every tack: tack, introducing more parts, complexity, and effort during
> tacking. Also, a potential point of failure in terms of sailing
> efficiently if the piston stops working. The Swing-wing will just flop
> over with the force of the wind, no hydraulics required.
>
>
>
> ---
>
>
>
> Of all the soft wingsails proposed, the swing-wing is the only I've seen
> that deals with raising, reefing, and tacking, without resorting to extra
> mechanical devices. No computer, hydraulics, or electrics required, and
> when it's down, there's zero risk of the boat sailing on its own while moored.
>
>
>
> It's also the only wing sail I could see myself being comfortable
> handling when a squall picks up out of nowhere. Drop. Done.
> Raise a bit. Done. Even my wife, who weighs 105 pounds, could do it
> easily if I were injured or incapacitated. That means a lot if we want to
> go any distance that will require one of us to single-hand the boat for hours
> at a time while the other sleeps.
>
>
>
> Assuming Omer's polars are correct, and it can exceed true wind speed
> with relatively little sail area and heeling moment, the soft wing is a serious
> improvement over a single skin. Even if the swing-wing is only half as
> good as the Omer, it would be a most impressive rig (again, especially when you
> include its low cost, complexity, and ease of use).
>
>
>
> - Mike
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> bjarthur123 wrote:
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> thanks for the info. i'll book mark it. seems similar to omer's wing sail:
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> http://www.omerwingsail.com/
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> ben
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> > The swing-wing is a soft wing sail, essentially a junk rig supported
>
> > by snowshoe-like wishbone frames to give the sail a double-skinned
>
> > airfoil surface for its leading edge.
>
> >
>
> > Because it works like a junk rig, it's easy to reef -- just let the
>
> > halyard down another segment, pull on the new downhaul, and you're
>
> > there. With a portion of the "wing" in front of the mast, it's
> at least
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> > partially balanced. Because it has a great leading edge that naturally
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> > orients to windward, it doesn't suffer the questionable upwind
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> > performance of a junk.
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> >
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> > The design is by Bertrand Fercot, implemented on his Wharram Tiki 30.
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> > He reports that his boat tacks easily and sails faster than a standard
>
> > Wharram Tiki 30. Details are at:
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> >
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> >
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> > http://wharrambuilders.ning.com/profiles/blogs/sailing-with-pha-tiki-30-n119-1
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> >
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> > Kim and Rudolph aren't really related to the design. I just like to
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> > mention them because they're the ones who convinced me it's a great
>
> > idea. Kim is the person who first mentioned the design in this forum,
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> > and Rudolph is the person who pointed out a lot of benefits that I
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> > wouldn't have noticed otherwise.
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> >
>
> > The original discussion can be found here:
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> >
>
> > http://au.groups.yahoo.com/group/harryproa/message/7314
>
> >
>
> > ---
>
> >
>
> > For a quick summary, it's the only soft wing sail I've seen that:
>
> >
>
> > - Can be raised and reefed with a single halyard,
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> >
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> > - Can be reefed or stowed simply by letting out on the halyard and
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> > tugging on one of the downhauls,
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> >
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> > - Can use soft heavy-duty sailcloth because the wishbones, not the
>
> > sail, create the shape,
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> >
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> > - Automatically shapes itself to the wind without hydraulics or
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> > additional control lines,
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> >
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> > - Has the added benefit of the low sail/sheet stresses of a junk rig,
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> >
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> > - Delivers the partially-balanced forces of an easy rig,
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> >
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> > - Reduces those forces further by creating a double-skinned airfoil,
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> >
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> > - Eliminates both the boom and sail track, which are noticeable
>
> > expenses once you include all the attendant hardware, and
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> >
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> > - Uses a fixed mast (no bearings!) and thus: an easier mast to build,
>
> > erect, and remove.
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> >
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> >
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> > Cons:
>
> >
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> > - Not as efficient as a solid wing,
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> >
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> > - Definitely requires some labor for the creation of those wishbone
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> > frames,
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> >
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> > - Not as established as other designs that have been tested for years,
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> >
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> > - Will therefore likely require some experimentation, and
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> >
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> > - May be tough to use as a schooner rig; it looks like those
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> > mainsheets need to be lead aft, and not just to the windward cockpit.
>
> >
>
> > ---
>
> >
>
> > Personally, I'm largely sold on this design if I go for a single
>
> > mast. I love the efficient shape, lack of many moving parts, and lower
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> > cost (if you don't count labor and experimentation).
>