Anyone running non-factory prop on R25/27 classic?

[NorthernFocus]

I'm contemplating re-powering our 2008/9 R25. As part of the exercise I've been studying prop alternatives for the engines I'm considering. And as part of that exercise I've been running the calculations vs historical performance of the boat. The boats have been around for a few years now so thought I'd ask what other real life experience people have gained.

So the question is simply per the thread title. Anyone running props other than the originally supplied 3-blade Acme? On the 25s the original wheels were either Acme 3-blade 17x15 or 17x14 both with 0.105 cup. Not sure but I believe the later R27s with the 200hp engine came with 3-blade 17x17 with 0.105 cup.

 

[Red Raven]

I had my prop on our R27 Classic re-pitched from the 3 blade 17x17 0.105 cup to 17x15.5 0.105 cup last winter because I could no longer reach the 4000 rated rpm (was only getting 3750). The boat seems much happier with the reduced pitch and runs at a lower temp though I think it now may be slightly under propped. Speed is a knot+ less (12kts) at 3400rpm but fuel burn is down as well. My max rpm lightly loaded is now 4150 and around 4050 with our typical gear. Pretty happy with it. The only thing I would add is for some reason it seems the RT boats get more increase in rpm for each reduction in pitch than expected. I was told to expect this from the ACME Propeller tech who said don’t overdo it. The local prop shop wanted to go to 15 inches as he expected 200 rpm increase for each inch in reduced pitch. I said I was more comfortable with16 based on ACMEs comment and we compromised on 15.5 with the promise he would re-pitch by .5” for free if needed. I still may have him make it 16 this winter when I pull the boat as I think that would be spot on.

IHTH,

Curt