Another Prop Question

[Dave Bressler]

I have a 2008 Nitro Fish and Ski with the 115 Tracker motor.



I am looking to get better performance out of the hole for pulling skiiers. What do you guys suggest?

 

[Bob Bourget2]

There is no better prop for your "requested use" than the Mercury Hi-Five. Five blades, stainless steel, tremendous stern lift and out-of-the hole performance. This is the prop of choice for tournament ski boats. If your 115 is the 2-stroke, be sure to prop NO MORE than 5250 RPM'S. That series of motor develops a harmonic imbalance at "higher-than-that" rpm's that could lead to crankshaft failure. If you are running a merc prop now, the stainless prop would be a pitch-for-pitch application.

 

[Dave Bressler]

So you are saying stay with the same pitch and just go to five blades? I was told a different pitch might be in order. (I have the stock stainless blade, though I can't recall offhand what the pitch is.)



Thanks Bob

 

[Bob Bourget2]

Yes, staying with the same pitch is correct IF...you are turning the correct WOT RPM.....do you know what that is?

 

[Dave Bressler]

I have not calculated my WOT RPM with the current prop. Thanks for the advice!!!

 

[Bob Bourget2]

Calculating WOT rpm is VERY difficult. You can get theoretical rpm, but the slip factor can vary. Typically, most high performance applications will run anywhere from 8 to 15 percent. Without an accurate tach and speedo, you would be guessing at best......GET A TACH. It is important on that motor!!!!!:blink:

 

[Dave Bressler]

Bob - Would a hydrofoil accomplish what I am looking for? My boat is very slow to get to plane.

 

[Bob Bourget2]

A hydro-foil may help to get you on plane. It is not a substitute for the "hi-five" however.....