24' Glasply, Aluminum or Stainless.....?

[AKJohne]

I have been running a aluminum 15.25 X 15P on this boat its done ok, but has acquired some dings and thinking about replacing and or upgrading.
24' boat 20 degree deadrise, 7-8K loaded, 5.7 LX, 1.47 Alpha 1 gen 2. Typical cruise at 3200 is 24-28 MPH, WOT is 4600 and ~ 38 MPH. none of these numbers are perfect but represents the typical trend's. I had a 16 X 16 aluminum and did ok but WOT was 40 MPH @ 4400 and that seemed low, had it repitched and now 33 MPH @ 4800. I think he went to far and not sure if its worthwhile repitching aluminum props. It was a experiment. Am I chasing ghosts or can I get some gains with a different prop. Also it typically requires some trim tabs as it is a narrow hull, drive is trimmed all the way in.. Thanks......!

 

[AKJohne]

Not looking for speed, just good performance and economy, if that's possible, when I said "low" with the 16 X 16 I meant the 4400 WOT RPM might be on the low side, I had someone tell me recently that 4400 WOT is a good rpm for those motors.. thanks

 

[Texasmark]

What are you currently running in material? Whatever it is, duplicate it with a 2" pitch reduction maintaining the diameter as close as possible to the current diameter....expect it to increase slightly as in the design of props, shallower pitch usually goes hand in hand with larger diameters in maintaining the same blade area.

 

[AKJohne]

What are you currently running in material? Whatever it is, duplicate it with a 2" pitch reduction maintaining the diameter as close as possible to the current diameter....expect it to increase slightly as in the design of props, shallower pitch usually goes hand in hand with larger diameters in maintaining the same blade area.

As mentioned, both props are aluminum. A 2" pitch change would potentially raise the WOT to 5000- RPM on 15P and 4800 on the 16P, the 16 I had repitched to ~ 14.8 and now WOT is 4800. (I Was looking for a 15.5P change) I dont think a 13P pitch reduction is going to do me any good.
I ordered a 15.8 X 15P aluminum 3 blade Solas. If the cup is similar it should be about right.

 

[Texasmark]

I apologize for my error prone reply. I must have had a brain fart. Getting more frequent at my age.