Now to the sail plans: thanks again for your effort! I have questions, and I hope you do not receive them as questioning your knowledge but really being interested in understanding and learning.
Arne, you wrote the mast position 300 mm forward of the WC will call for a fairly broad sail. If not constrained by the WC (as everything is above deck), would you go for a narrower sail? Why? This would of course mean a vertically stretched sail plan if the sail area should remain constant.
If freed from any constraints, would you move the mast more aft? Why?
Regarding Ingeborgs sail on Ilvy (that's the name of my Maxi 77): Would you rather reduce the sail area on Ingeborg? Why? If the 35 m² sail fits an IF, why would you think it too big for Ilvy? The Maxi 77 is definitely showing more initial stability due to the U-shaped hull than an IF, and due to the deep keel (compared to an IF) and keel bulb probably also more total stability.
Graeme, what is it that makes you vouch for the excellence of the shown SJR? Do you experience heavy upwind performance boosts or something like that?
How does it affect your sailing that your SJR only has on triangular panel? Did you ever sail with that last panel only?
As the tabernacle thingy will probably take up enough of my junk rig conversion time, I am a bit hesitating to really go for a SJR (though I really like the concept of it! I will probably end up with a huge knife in my hand, in the swedish archipelagoes, frantically cutting vertical scars into my cambered junk to make up for not having gone for a SJR...)
Luckily, me and my girlfriend Toni were able to sail on sunday with Kay from Lübeck. The opportunity really came rather quickly! He is a nice guy and was very kind to take us along in force 6, gusting 7, for a junk rig demonstration ride on the river Trave. We did not enter the open sea, but had some fun on Dassower Wiek (kind of a lake which is connected to the river Trave). It was very interesting to finally be onboard a sailing junk rigged yacht. It was a Westerly 22, with bilge keels. However, though it was fascinating to speed away downwind and on a broad reach, we were almost not able to keep our height when beam reaching. Sailing on a close reach or close hauled was not possible at all. We were not able to sail even one degree upwind... Also, from about five attempts to tack, none worked out. We lost all speed of the boat before the nose went trough the wind, so that we were bearing away involuntarily every time. Luckily, there was enough leeway to gybe. In the end, we tacked once - but involuntarily due to a brutal wind shift. This experience was quite frustrating for me, as I wanted to show to Toni that tacking up fjords in Sweden would be the easiest thing on earth with a junk rig. Now my arguments were slipping out of my hands, and me stammering theoretical aerodynamic explanations for what we just experienced also did not help. Of course, there was a lot not being in favor for that junk rigged boat: bilge keels, rather strong winds, reefed down heavily... and the rig was obviously designed to survive into the next millenium. Even me, a newbie to junk rigs, could see that the rig was way too heavy for that little boat. That was also what Kay expressed. He bought it with the rig, and is considering changing it for a lighter one. We are not talking about some racing windward abilities of carbon sail enthusiasts here, but at least some ten degrees could be possible. Really, it was quite interesting to see that this boat totally rejected to sail to windward or tack.
On the next day, Axel called me from Essen with his junk rigged BB17 "Athena". I shared my still fresh experience from sunday with him, and he couldn't believe it. His boat is running to windward as hell, easily (or almost) keeping up with an IF. He never even dreamed in his worst dreams of a tacking maneuver going wrong. He did sent me very nice drone shots of him sailing with his fine yacht. It showed impressive upwind performance, tacking angles of about 90° and smooth tacks. That was more of what I imagined...
Those videos also convinced Toni, so all is well!
Sure, "Athena" got cambered sails and mast and spars of just the right dimensions (fine work of the sailmaker "Tuchwerkstatt" in Greifswald) and also, she is quite a fast running classic yacht. A bilge keel yacht is another story, but still...