New Prop Question (formulas)

[blaze]

Does any body know the formula for working out props
I want to know the difference between
19p and 13" dia
&
15p and 14" dia
how close are they, It is pretty easy to put them on the boat and try but if you happen to come across one and want to estimate what it would be like without trying
cheers
blaze

[Brett_Hoskin]

http://erienet.net/~russclara/propcalc.htm here mate give this a go?

Enter in what you know about your existing setup to calculate slip. Re enter the info with the slip and us e the program to calculate speed.