I have a slow cruise and a fast cruise. 4200 rpms = ~29mph/25knots at 18gph and 4800 rpms = ~ 32mph/28knots at 22gph, fully loaded, canvas on, good conditions, years of bottom paint etc.
WOT = 5800rpms, half fuel, no gear, no canvas, ~40mph/34knots maybe a little more depending on...