Speed question

[boatfreak]

Is there a formula for speed with a prop change. I don't mean top speed but rather say the difference between a 32 and a 34 Bravo at a given rpm, say 4500 or 5000. I quess you would have to say the two sets are exactly the same other than pitch.

[Philm]

http://www.go-fast.com/Prop_Slip_Calculator.htm

[boatfreak]

Thanks, I have used that before but forgot all about it.