Props, RPM, MPH

[fishnowworknever]

There are a ton of variables that come into play when it comes to prop selection. But I'm hoping someone can chime in with some info.

My current setup - 17' glass boat, 90hp Yamaha with rpm range 4500-5500

Right now I have a 13 x 19 3 blade aluminum. When I am alone with normal gear full tank etc I can get up on plane just fine, trimmed out i'm hitting around 4800-5000 and usually top out around 38-40 mph.

I just purchased an aluminum 13.25 x 17 hoping to get my RPM's up near or at 5500. From what I understand if I can get to 5400-5500 I may pick up 1-2 MPH since I'm not hitting that power band using the 19 pitch...even though a higher pitch will give you a better top speed...and my hole shot should be much better with this lower pitch...

Any thoughts on this?

edited: current prop is aluminum not stainless...not sure why I typed that

[hydro]

Have you tried your new prop yet? Give it a run, see what it does,and post your results.

[luckydog25]

I just went from a 19 aluminum to a 17 stainless with extra cup. The prop shop said the extra cup not even sure what that means. Anyway I was having trouble getting on plane if my boat was loaded down. Switched to the stainless 17 and it planes perfect and gained 2-3 mph. The boat is 17 ft aluminum with a 115 optimax. It worked for me, but my only concern would be you will lose with switching to aluminum whatever you gain in the rpm's.

[fishnowworknever]

No I have not...I probably won't get the chance to try it out until Wednesday. It's a slow day at work today and I'm 2nd guessing myself with this new prop...but you're right I just need to get out and try it.

Thanks

[fishnowworknever]

luckydog25-

I edited my first post, I guess I need to verify if my original prop is a painted stainless or aluminum.

Either way the prop shop told me I need to get that motor up near the top end of the RPM range at WOT and the current one is not getting there. Maybe if this new prop pans out I'll look into a stainless with the same size/pitch sometime in the future.