Interesting Paul.

It would seem to me that the amount of 'drift' from centre of the anchor point would relate directly to the desired yard angle.
Do you have the numbers on that relationship if it is indeed the case?

x 'drift' = y yard angle.

David, yes, it is fully possible to screw up when making a Johanna-style sail.
It seems that quite a few just pick elements of my designs and then drop others.
The results are often ‘interesting’.
The standard failure is to not fit the parrels correctly, HKP THP and even the YHP. Then they drop fitting the tack-line and make a 6-part sheet to own design with no anti-twist in it.
Then there are the super-tall sails with almost vertical sheets, some even set on forward-raking masts, and schooners with too little clearance between the sails. I could go on (...yes, omitting the important boltrope   -  and of course the telltales, and, and , and...).

However, if they just pick one of my master sails, and follow the instruction, they stand a good chance. After rigging the sail by the book, so to speak, without pushing the limits, there is very little tweaking to be done afterwards. I stress; a sail is not completed until it has been correctly rigged.

There are of course other ways of making good junksails with cambered panels and straight battens. Paul Thompson seems to make very fine sails, and more and more of Slieve McGalliard’s Split Junk Rigs appear to be fully operational and very good, these days. And then there are some successful amateurs spread around the world following their own ideas.

As for Martin Simmons(?) and his Taiko, I have no idea. I don’t know his boat and have never been contacted by Martin.

Arne

David,
the high peaking of the yard is not the point; it is how the sail looks like below the yard.

I understand that Annie had quite some problems with getting Fantail’s sail set well, and that HK parrels used to bend the battens upwards. Fantail’s sail has much in common with the mainsails of the Hong Kong schooners in being very low-AR, very unbalanced (with respect to mast) and in being fanned all the way down to the boom. As can be seen on photos of the HK-junks, they used HK parrels, which clearly saw huge loads. Therefore, the battens were beefed up substantially: One can see they are made up of bundles of bamboo  -  and they still bend quite a bit. On Fantail’s similar sail (not that extreme, though) the battens were clearly undersize, so could not stand up to the needed tension from the HK parrels. Clever use of luff-hauling parrel(s?) sorted it out.

The Johanna-type sail  -  my take of Hasler and McLeod’s standard sail, is a different animal than a true fan-sail. Only the top three panels are fanned, while the lower 3-5 ones are not much different from those in Weaverbird’s or FanShi’s sails.

It is true that the loads on the THP and LHP were considerable in the sail of Johanna. However, I learned from this and increased the halyard-to-slingpoint drift on later sails. This both let me move the halyard’s slingpoint about 5% aft of the middle of the yard, and the YHP was moved 2/3 up. These two measures have reduced the forces in both the YHP and THP, maybe with 50%. Below the top section, the parallelogram panels live an easy life. The Hong Kong parrels now only work as lightly loaded (fixed) stabilizers. When sailing up and down my fjords, I never have to touch the THP or YHP underway, except when adjusting the sail area.

Initially, getting the rigging right on a Johanna-type sail is no rocket science: Anyone who can read, can find how it is done in chapter 7 of TCPJR. It’s all there in plain Stavanger-English.

Conclusion:
I simply don’t buy that the Johanna-type rig with straight battens and cambered panels is some sort of expert’s rig, best kept inshore. Too many deep sea voyagers have proven that it is seaworthy.

Arne

I move to here from  the «Pottering is...» thread
There, David Tyler wrote 27.6.2021:

“Arne,

I'm corresponding with a JRA member who has just completed a 2800 mile passage and thinks his baggy sails, made to your specs, may be suitable for fjord sailing, but are are more trouble than they are worth for ocean passages, and wants to go back to hinges.

Horses for courses.”

David, I might have bought that argument if no other vessels had had success with sailing across the oceans with cambered panels only. However, I haven’t heard any complaints from deep-sea sailors like Alan Martienssen or Roger Taylor. I have seen some cambered panel sails that look bad, but most of their owners have not completed the rigging properly, like fitting THP, HK parrels, or getting the sheets right.

Arne

David,  going back to your previous comment, why would you not first add the pocket to the end of the sail roll, then sew on the next panel?   Thus only a rolled up panel to pass through the machine and nice flat seams. 

For a cambered sail, the main panels could be joined by a lens shaped panel to which you first sew the batten pocket.  The lens shaped panel gives the camber, and can be made out of a lightweight nylon to  be more stretchy.  With contrasting colours for main panel and lens panels you would have a pretty funky looking sail!

(having yet to make a sail, hope this is not a stupid comment!)