New prop for 170W Lowe

[podcast]

Hey all, had this boat out 3 times last fall and once this spring. I bought it knowing it needed a prop since it's the original and fairly beat up.

The old prop is a 13x19 and I'm turning 5,800 rpm at 36mph. My motor is a 2001 70hp Yamaha. From my research this is near the max rpm for this motor.

My question is opinionated. So, in your opinion and/or experience, would a 13x21 do this setup good? Possibly take the rpm to 5,500 and 38-40mph?

Thanks for the responses.

[Princeton_Man]

You don't say if that's a 2 or 4-stroke Yammy?? If it's a 2-stroke, I'd say you're right where you wanna be. I looked up the newer 4-stroke and as odd as it is, they show a WOT top end RPM of 6300 while the 2-2troke max is 6000. I don't think you'll pick up more than a couple mph and an increase in pitch will slow your hole shot. If at all possible you should see if you can try before you buy.

[podcast]

OK, make sense.  I think I'll stick with the prop I have.  Not that speed matters all that much but it seems that I'm slower than most with a 70 on this setup and I'm a really little guy so passenger weight is not the reason 

Also considering the new prop will be in, well, new shape and this prop is fairly worn it's likely it will hit the sweet spot.

Thanks again.