RPM - MPH Conversion?

[Bradf]

Sorry if its already been posted;
I was wondering what the mph conversion was at 4500 rpm w/ a Berk B impeller... Or what it takes to find your avg mph at that rpm...
what this boils down to is my cheap @ss not wanting to buy a cheap gps lol

[Cas]

not sure what it is but you can find the chart on the cp performance website

[Oldsquirt]

Brad, there is no direct correlation for RPM/MPH that can be universally applied to all boats. The engine/pump combination you have will provide different speeds in different hulls. More drag=lower speeds, less drag=higher speeds. All depends on weight, length, hull design, condition of bottom of hull, etc.
Cas, were you perhaps thinking of the ImpellerRPM/HP charts not MPH/RPM ?

[kp216]

The JPC will give ballpark figures IF you have reference points already established, such as if your boat has an "X" impeller turning "XXXX" rpm and the hull speed is "XX", then if you increase your rpm to "XXXX", it will require "XXX" amount of horsepower and your speed will be "XX".

[Cas]

Cas, were you perhaps thinking of the ImpellerRPM/HP charts not MPH/RPM ?
yes sir, that I was!

[Bradf]

Ahh, I see. I didnt consider all the other factors. Looks like ill just have to buy a GPS lol. Thanks guys. I appreciate the replies.

[skeeter]

Pick up a garmin 12 on ebay which will log the maximum speed obtained during a run. I have been using one for years and would throw rocks at a radar gun after realizing how accurate they are.
You can find one for around 50 or 60 bucks...