Lat Nov I was returning from a Race south of me in Seattle, was heading north in 20-30 knot winds, full main and 155 up. Heard a thumping sound for a bit, figured out it was the prop, ie my max prop turning. At the time doing upper 6 to low 7 knot water speed. HullSpeed is 6.6 or there abouts, ie 24.5' WL. Put the trans in revers, thumping stopped, soon after gained some .5 to 1 knot speed, within a minute! Eventully as the wind piped up, we were doing low to mid 8's, even in to the 9's!
While I understand the reason for a fixed like Main sail mentioned, crab/lobster pot issues, for many of us, the foler/feathering prop will net some speed, not matter the speed we are going, or wind speed!
She drives me boat,
I drives me dinghy!