http://junkrigassociation.org/photo_gallery?id=9416620&dh=256&cppr=3

Is this the ‘perfect’ sail for a proa?

The area in front of the mast could be increased to give an almost balanced sail.  This would give a minimal movement of the CoE between shunt. 

It has a good windward performance, apparently as good a cruising Bermudan rig.  It can be readily reefed and can feather to the wind, so ideal for any multihull.

I think it would be improved by using wishbone battens.  There is a pointy-headed version of this in the latest JRA magazine, refered to as an Aerojunk.

Regards
Mark

If the split Junk is as powerfull as the balanced lug it should be a very good sail for a proa. There is always the balance of “torque” vs “rpm”. The low aspect traditional sails have lots of lift at low windspeeds and is perfect for medium to heavy boats. They loose some performance at higher speeds due to apperent wind-angle and flutter in the leading and trailing edge.
Compare this to large Caterpillar marine diesels and high rpm motorcycle engines. They both develop 200 hp.

Cheers
Johannes

I think that there’s potential here as well…

It’s definitely the one I intend to use.  the 35% chord it can have in front of the mast combined with a mast set a bit to windward of the Vaka, and I think I can attain good balance with both rudders always down and interlocked.  The ultimate short shunter, and I believe an excellent performer as well.

Tom

Lets see some drawings, Tom.  Where are you now with the design?

best,
chris

This is where I parked a couple of months ago.  Like I said, I’m in the process of purchasing a shop with a small house attached 😉  I was going to get serious once that was locked down.  I’m waiting for the bank to get off their dead ass and accept my offer.

It’s just short of 24’ overall.  as drawn, it’s 24” across the bottom, 48” across the top.  Topsides are 48” wide panels.  I drew it for maximum load capacity on 24’ while still carrying @ 10:1 at the load waterline.  I might narrow down to 16” on the bottom and 32” tall topside panels.  I’ll definitely increase the rocker to match 1/2 the maximum bottom width to (I.E. 8” rocker for a 16” wide bottom, 12” rocker for a 24” bottom etc….

I might even swap the motor and mast locations.  I definitely need to make the well a bit deeper, or get a longer shaft motor that the 5hp eska I measured that I currently own.

I would do the sheeting the same way Brett did, or a close facsimile.  I’ll need extensions at each end to bring the anchors to windward to get a tight enough sheeting angle.  Obviously lots of details yet to work out, but this is the basic concept.

Tom