In answer to Mauro, I submitted a question on SJR to Chat GPT.  "What is split junk rig". I was not surprised that it was unable to provide any information on split junk rig but I was horrified that instead of returning no answer, it produced a lengthy spiel of complete rubbish including the confident assumption that the split is horizontal and for all kinds of spurious reasons, plus a lengthy spiel on all the cliche advantages which were of no relevance. That has diminished any credibility I would give to AI as a source of factual material (it has some other impressive uses, but not fact-seeking).

A Google search did better, and pointed directly to the JRA website and various online articles which were somewhat more relevant.

Well, a different AI engine called “Claude” did quite a bit better:

So have I...

Edit:
I’ll add a few ideas here, as they come to mind:

1.
The flat sail junks from the seventies and eighties performed much worse to windward than the Bermuda rigs. Everyone could see that. However, these flat sails lasted for ages and were ‘never’ improved with camber, either by using hinged battens or by making new and cambered sails. The result is that the reputation of the JR is bad, and for a good reason. I notice that new flat sails are being made by sailmakers, even today.

2. Sails are cut as big puzzles from computer programs today. It is unlikely that sail makers (big companies) will invest money on developing expensive programs for cutting out junk sails, since these have gained such a bad press over the years.
For this reason, the JR will mostly be for home-making (with a few exceptions).

This is a very goo question Guillaume!

Also in Italy (where I was born) and in Austria (where I live), junk rigged boats are inexistent and considered in best case as exotic, wired experiments.

By the most yacht sailors I spoke with, a rig other than the bermuda one with shrouds and foresails seems almost not imaginable...even when the most diffuse sailboats in their own yacht clubs are cat boats with unstayed masts and single sprit sails (the Optimist) or Marconi sails (the Laser)!

Like Paul, I've also found most comments from Bermudan sailors about this issue simply irrational.  

Anyway, there are a lot of designers that show attraction for the JR, two examples:

Tom McNaughton (http://www.macnaughtongroup.com/designs.htm)

Eric Hanseval (https://hensevalyachtdesign.jimdofree.com/monocoques-6-50m-11m/divinite-7m-exp%C3%A9/ ).

Last but not least, interestingly the english page of Wikipedia about the JR is quite up to date and points out very well some of the advantages of the JR in comparison to the bermuda rig: "Maneuverability in a junk rig is vastly beyond that of a fully stayed Bermuda sail rig..." (https://en.wikipedia.org/wiki/Junk_rig)

Good luck with your interesting project.

Mauro 

Hi Guillaume,

that is the one most frequently asked question I hear when promoting the junk rig (beside the usual "but does she go to windward?").

From a rational/technical/sailing perspective, I see no answer. I could only speculate about non-rational reasons...

Very nice that you are looking deeper into it!

Cheers

Paul