Re: prop question?
The prop is similar to changing gear ratio's........
Yes is you go up in pitch (in theory) your speed could go up IF you have the horsepower to turn the prop. Notice the big if. If you were riding a 10 speed bicycle there is a gear that you are capable of turning as fast as you can say one of the lower gears and if in the highest gear....... you do not have the physical power to use it to take off or max out.
If you install a prop too large (high pitch)it will not perform and just lug the motor which is bad........ if you install a prop too small the motor will rev too high which is also bad.
Prop swaps need to be done with a tachometer installed to insure you are running and capable of running at WOT. There is no rule of thumb since every hull and every boat carries a different load. Boat weight, hull design and people all have an effect.