Dominic Lawson · Knows English:
A ‘drafts’ man (USA) or ‘draughts’ man (UK) is referring to the ‘Drawings’ created. Drawings are draughts in old Latin.

We still use it in everyday language, meaning to make a rough drawing. A draft.
#iweb3 #draftsperson
https://www.quora.com/Why-is-there-an-s-in-the-middle-of-draftsman-What-is-the-semantic-origin-of-it/answer/Dominic-Lawson-25?ch=10&oid=1477743635083555&share=9abedc5b&srid=uNtVLI&target_type=answer