Because Tailleur asked about it at dinner tonight: draw originally meant 'pull' or 'drag'. The sketching sense of draw arose around 1200 from the sense of pulling a pencil or pen across the page. Draught and the later spelling draft are nominalizations of the verb (following the same pattern as drive–drift and give–gift). The alternation between w, gh, and f (and in some other words, y) seems pretty weird, but it all goes back to a g in West Germanic. Between back vowels /g/ eventually became /w/, between front vowels it became /j/, and before some consonants it became /x/ (like a German or Hebrew ch), which was often spelled gh in Middle English), which then either disappeared or turned into /f/ in some instances.
