These are the measurements taken from a Heddon 3/2 #17 Black Beauty in 8 1/2' length and a size 2f ferrule. Designated for line HDH or E which is a 6DT and whatever "E" is. I subtracted .004" for varnish. Chris McDowell 1" .078 5" .094 10" .106 15" .122 20" .137 25" .146 30" .159 Ferrule 36" .174 40" .189 45" .204 50" .217 55" .230 60" .250 65" .264 Ferrule 70" .286 75" .299 80" .310 85" .324 Swell begins at about 89" (.346) 90" .395