which prop do I need?

[sgtallen414]

Hi everyone!!! I am new to boating, Just got my boat up and going yay!!!! now time to fine tune this thing. I have a 1980 16ft checkmate ski boat. the prop I am using right now is a 19 pitch. the boat tops out at 38mph and only goes 5000 RPM WOT. and it is not doing good with a tube. What prop should I be using and is the number given above sound about right for the boat with a 115HP Johnson V4 2 Stroke? Also I have a 16 pitch stiletto I could try... think that will help?

 

[alldodge]

I'm seeing the 2 stroke WOT at 4500-5500 rpm

Hitting 5000 your in the good range so need to make sure your tach is accurate

If tach is accurate, is speed reading with a GPS, if not need that

If all is GPS and accurate, then your at 15% slip with 19 prop, 2.0 drive, 5K rpm

 

[QBhoy]

I have never had nor seen a check mate up close. But as far as I’m aware, they are usually quick things. I would have thought with a 115 smoker...you’d be at least mid 40’s but likely around 50ish gps well propped.
I have a glastron cvx16 (similar size and weight I think) and it had a 115 Yamaha 2 stroke on it for about 35 years or so. She now has a 150 V6, but previously she was apparently good for well into the 50’s with the 115 and well propped

 

[jimmbo]

What year is the 115? Some were crank rated, later ones were prop rated