Another Prop Question

[76Red18]

Originally Posted by Commander Coo1

Fr. Frank,
It isn't really all that uncommon to see a prop produce low to negative slip numbers. Suzuki, stilletto, and BRP Rebels just to name a few manufacturers/props are "under rated" in their pitch disignation and may produce low calculated slip numbers on a smaller vessel.

Surely the Rebel 15p I ran could not have actually measured as a 15p propeller. But unless my GPS, EMM/NMEA2k RPM readout, multiple test runs in opposing directions or 1.85 gear ratio are incorrect, I am getting the calculated slip numbers that I previously reported. I know 0% slip is basically impossible, but you can't assume that less than 8% slip is nearly impossible on a small fishing boat.

I have seen WOT slip as high as 12% (BRP Viper 19p) and as low as -4% (same Rebel 15p prop running at 4500rpm) on my setup using the same measurement methods. props can produce unexpected results and produce theoretically impossible numbers at times due to how the manufacturer designates their propeller pitch.

pair of jacks,
I think that the Enertia will do well for you, I really have been enjoying mine since I got it. Much more predictable performance than the Rebel I have! I look forward to hearing how it performs!
-James

ALL props will slip. You do know the good Father was throttle man or driver in quite a few races back in the day don't ya? He knows a little about slip numbers I would imagine.
I do agree that a few makers do understate their pitch numbers which means that the prop calculator is just a tool to get you close.