Help choosing prop

[66stingray]

Hello,

New member and relatively new boat owner. I have a 2005 tracker marine Tahoe 254. Its considered a deck boat with a 350 Mag mpi, 300hp and bravo one sterndrive. The gear ratio is 1.5 and the boat weighs approximately 2,800lbs without engine, roughly 3,800 with the engine and has a 63 gallon gas tank. Its mainly used in a Bay environment in NJ. Wot is approximately 4,800 to 5,000 rpms. I have taken the prop off during winter storage and want to replace with a new aluminum 3 blade. Current prop is a 3 blade aluminum 14.5 with 19" pitch. My performance at the moment is good, gets up to plane quickly. I am considering sticking with the current spec (14.5 - 19") or changing to 15 - 17" pitch, still 3 blade. By changing diameter and also pitch, the 2 should remain at the same rpm range. What advantages/disadvantages will the difference in diameter have if at all? Looking for all around performance, don't want to lose any top end speed.

 

[SkiDad]

RPM will probably go up on the 17 and speed down. I would stick with the prop you have and just get a new one of the same brand and model

 

[Georgesalmon]

Diameter makes very little difference pitch is the big one. If you go to the 15 pitch you will likely over rev the engine at WOT.

 

[Bondo]

I am considering sticking with the current spec (14.5 - 19") or changing to 15 - 17" pitch, still 3 blade. By changing diameter and also pitch, the 2 should remain at the same rpm range. What advantages/disadvantages will the difference in diameter have if at all?

Nope,.... It don't work That way,....

Prop sizes run by Pitch, the diameter is adjusted by the design engineers, generally more diameter as the pitch drops,....
It's Still a 17" pitch prop, 'n yer rpms will go Up,....

 

[Watermann]

If you're using the original prop then buying a new one with the hub kit is the way to go. Quicksilver black diamond or Michigan Wheel they both interchange with the same hub kit. It makes prop replacement easier, cheaper and to have a spare you just have a prop shell. The newer props over the ones from a decade ago have some advantages like increased cupping and a more aggressive rake which will also lower RPMs because the prop will bite into and hold the water more effectively. The casting process is improved too. Even so I agree to stay with the 19" pitch as 5k wot is close to over rev if the tach is correct.

 

[Sea Rider]

Which are your current wot numbers while lightly loaded and just one man up on flat calm no wind water cond, that's with a healthy tach ? If at the top or near wot range stay with that prop, bear in mind that as soon you start to add more weight or passengers wot rpm will drop accordingly. If wanting a family oriented prop will need to test under that cond and check achieved wot numbers, depending on results can go for a prop maximization playing with less prop pitches to increase lost top wot rpm while testing alone to suit your particular boating/family oriented needs.

Happy Boating

 

[66stingray]

Thanks for the responses. Good info. Was not aware of the pitch/ diameter difference not being linear. That is a 17 pitch prop still raising rpms despite diameter increase, So I will stick to the current 14.5 to 19 pitch that I am running now. Just thought now would be the time to experiment with different set ups if im getting a new prop. Going to go with a quicksilver black diamond.