Cambered and modified Junk rig. How to marry a Junk rig with a Dyna rig.

[toni ruiz]

Hi friends.

I am very interested on developing alternatives to existing JUNK RIG DESIGNS based on a compromise reuniting the following premises:
1)The simplicity and easy of maneuver of the junk rig ( HARD IF NOT IMPOSSIBLE TO BEAT!)
2)Afordability of the same.
3)Windward performance of the wing or as a second... a well tuned up marconi.
4)The toughness of the gaff AND ITS EASY REPAIR.
Is that possible? Probably not as a whole but maybe ther are workable compromises.

That is what I am driving to, hopefully with the group's help....here it goes....

1) Imagine a junk rig were the mast is located at the center of the sail like a Dyna rig instead as on the traditional junk.
2) The battens would not be part of the mast like on Maltese Falcon but would slide up and down as on a traditional junk. Tha sail being well supported could be made of fairly light material.
3) the battens would be permanently CAMBERED AT ABOUT 5/8 DEGREES and MADE OF A fairly stiff BUT LIGHT MATERIAL, ALL PARALELL TO EACH OTHER, and prtactically horizontal, 6 to 8 of them controlled by JUNK LIKE PARRELS, on each tack very much like a Dynarig
4)The mast would be naturally UNTAYED, allowing the sail to swing with each tack and to lay flat againts the wind running and broad reaching. The rig would allow for a possible removable back stay to be use to reduce mast wipping in heavy weather or as an ssb antenna. THa sail would JIBE INSTEAD OF TACK, ON EACH TACK SIMPLIFING AND LOWERING THE RISK OF EQUIPMENT DAMAGE and making it self cocking
TWO SET UP OF PARRELS "COULD" help modify somewhat the camber if so designed.
5) The sail shape WOULD ALLOW FOR A MUCH IMPROVED winward shape on each tack (when compared with a standard camberered junk) an excellent when sailing downwind, same or very similar ease of reefing to the traditional junk.
5) one single sail per craft ( up to a moderate size boat) better performing that multiple set ups, more economical and manageable. The mast alway to leeward bu when running.

These are simply some "elocubrations" to open the forum/////

ANY TAKERS?

[Bertrand FERCOT]

Hello Toni

Bolger and a few other people have imagined a such rig, have a look at this web page :
http://www.proafile.com/view/weblog/comments/rig_options_bolger/
and their conclusion is this rig is very difficult to control.

Personally I'm very interested to generate the sail force mainly with a deep curved sail with no or minimum angle of attack. It's why I've tested on my tender this rig :

The problem is as the mast is in the middle of the sail axis, the sail is not steady : with no angle of attack the sail force is on the middle and with an angle of attack the sail force moves toward the luff. In light wind conditions I can control the tender, but in heavier winds + pitch, roll and gusts, the angle of attack changes very quickly and the leech sheets are unable to control the sail angle because there is not a continuous tension on the sheets as with a configuration with the mast near the luff.
Perhaps with a heavy hull it's possible, but with my light tender, I'm unable to tack facing the wind excepted in light winds. At my eyes, a boat unable to tack facing the wind is a dangerous boat.

Bertrand

[toni ruiz]

Hi Bertrand
Let me start by saying that I admire your dedication to the site and involvment with Wharams and Junk rigs.
Thank you.
Regarding your answer, I believe that is very much to the point and very useful.
I am familiar with Bolger having built a couple of his designs, as well as having read about the rig in question. I was not familiar with any test, for which the one you sent is very enlighting. I need to re read it with more time but it definetely shines a good deal of light into the issue. Also your own experiences sounds very interesting.

I also though long and envisioned possible problems with luft tension as well as camber shape. Naturally to any new idea (and old for that mater) you can come up with possible issues and that is the reason for me opening this forum subject., to try to find , if possile alternative to what sounds like a potentally good option. ( By the same token is somewhat disappointing top think that the Chinese, held the similar design for hundreds of years practically, remaining unchanged...or were they/are they as conservative as we are?)
In Maltese Falcon the idea works but of course its sail control is totally different. Very high tech, read expensive. Each panel is controlled individually, the battens are solidary to the mast rotating with it etc, etc.

The issue that you mentioned about the luft moving forward, that is worrisome...could it not be minimized/controlled by applying les chamber to the upper battens and or reducing their length?

just elocubrating