Paul Thompson wrote:
The only modern (relative) developments that I am aware of was the adoption of cotton for sails and the Hongkong Parrels to put back diagonal stiffness that the cotton sails took away.
There seems to be 4 or 5 methods the chinese employed to keep sail shape, Hong Kong parrels just one of them. I don't think any of them relied on the fabric itself to hold rig shape, except the Hasler/McCleod flat sail design. (I have Worcester btw)
I suspect when the Cantonese (Hong Kong region) got their hands on good cotton fabric they altered the design thus invented the Hong Kong junk rig. Its larger panels/fewer battens was the key, better performance i suspect.