The lower the propeller pitch, the better your “hole-shot”, or ability to get up to speed very quickly from a standstill. However, this improved acceleration comes at a price: top speed. Lower pitch will cause your engine to reach maximum rpm at slower speeds.
On the other hand, a higher pitch affects your boat performance by delivering greater top speeds, but at the expense of your acceleration or hole-shot. (Warning: lower-horsepower engines can bog down if fitted with a propeller with too high of a propeller pitch. This can cause heavy wear on the internal engine parts, who will have trouble keeping up).
If you’re changing the pitch on a recreational boat, there’s a rule of thumb often used that says each inch of pitch is generally worth 150 – 200 rpm. Lowering the pitch increases rpm and vice versa. So for instance, if you were to lower from a 23-pitch to a 21-pitch propeller, you’ll increase engine RPM by about 400 revolutions.