Re: Purchased our new toon. Have some beginner questions.
Ok..IF, you are htting the rev limiter, the 200 rpm rule is not going to apply, because what you don't know, is what the rpms would have been had it NOT been stopped by the limiter. The other thing, is that depending on where you are in the power band on the motor, the rpm drop may not follow the 200 rule....is just a rule of thumb.
The pitch value literally means that with each revolution of the prop, the boat with travel X number of inches. So, a 10P prop will move a boat forward 10 inches with each revolution and an 13p will move the boat 13 inches. This rule assumes NO slip, or in other words, no loss in efficiency, which you will always have. The other thing that happens is that aluminum props tend to lose their shape and flatten out at higher revolutions. So a 10P prop really becomes more like a 9p or even an 8P prop if it spins fast enough. Stainless prop remain fixed and don't lose their shape.
As you increase pitch, you place more load on the motor and make make the motor work harder and the rpms will drop. This is why you don't always get more speed by changing prop.
In your case, you are hitting the limiter, so you are leaving power on the table so to speak. You know you will have the right prop, when at WOT your motor is making the most possible rpms w/o hitting the limiter. IMO, the perfect spot should be just above 6,000. Its not the pitch that matters so much, as the rpms.
