New to propping... Need help with an old crest

[srxr700]

Hey guys, need some prop help. I have an old 78 crest pontoon. 21ft with a 95 mariner 50 triple. I'm running 4400 rpms with a 10.75x12 prop. What would be a good option to get the rpms up?

[teecro]

Ballpark is for every one inch of pitch you drop you will gain approx 200 RPM... 21 foot with a 2-smoke 50 is going to be working pretty hard reguardless... Keep in mind that dropping too much pitch might bring up the RPM but can cost both speed and bite to which you end up with a boat that is harder to steer at slow speed.

[srxr700]

Sounds like its more or less trial and error. I think im going to try a 12.25x9 and dial it in from there. I know that the 12p I have on there is bogging the motor down.

[srxr700]

Just in case someone reads this someday who is looking for help...I ran the 12.25x9 last night. Really settled the motor down and I saw around 4900 RPMS at full throttle. So the 12.25x9 was a good choice I believe.