I have Traders old SF 20 with the DF 140. I have run it many years with a factory aluminum 14X21. I just put on a Powertech 4 blade 14X19. The old prop was a little beat up, but mostly I am after more stern lift and lower speed on plane. Yesterday I was able to stay on plane at 11 kts. with full tabs, half fuel and motor trimmed down. Also less stern squat and higher turns at no-wake speed. It looks like I am gaining about 2kts at my preferred 4K cruise turns. Early days yet for numbers. The mud is soft down here in NC; if I were still up in the rocky north, I would go with aluminum.

Nice tip thanks for posting...lots of us have 20's

strick

Hey Loon, what kind of top end are you getting?

Haven't had a chance to play with WOT with the 4 blade yet. I did see cruise at 4000 go from 20 to 23.

Numbers
 

Albie season ended, so played a little with the new prop. With about 35gallons of fuel and just my 180#, I had 30 Kts on smooth water. I continue to think it is a little over propped; only had about 5600 rpm at wot. I only had it wot for maybe 10 secs as I am a bit skittish since I had a driveshaft break earlier this year (old prop). I replaced the lower unit but there is a bushing in the midsection that bought the farm.
Next season I may try a 14 x 18 4-blade.