Hey up, EdS
For the chapter and verse about the manufacture of any sort of natuaral fibre rope, you can,t do better than have a word with Des at Footrope Knots.
You can find him on the web, someplace.
Charmin, guy to talk to and very very knowledged, take my word for it.
I would add that , if youre wanting to mess around with hemp rope, you,ld be well advised to include a reference to Hempex, a modern, artificial-type of hemp, which, not only handles and works the same as, but, damn me , even smells the same!
Des can tell you all about that, too.
regards
Seagull