correct prop size???

[fbait4562]

I need help deciding which prop to put on twin 225 Optimax installed on a 31 foot boat. I currently use 19 pitch but think I might get better perfomance from a larger prop. Any ideas?

 

[Bob_VT]

Re: correct prop size???

Let your tachometer be the deciding factor. Are you achieving WOT? Add your tach reading to this post along with the boat weight/length/type and people will advise you. A higher pitch will lower your rpms and a lower pitch may raise the rpms too high. There are occasions where a lower pitch will achieve higher performance by allowing the engine to reach WOT at optimum RPMS.<br /><br />Bob

 

[Dennis4b]

Re: correct prop size???

If you have no problems reaching the high end of your max operating range for the engines (carrying normal or less than normal weight), i.e. you have some throttle left to spare, you could try larger props.<br /><br />You'll only get more performance out of it if you would currently be able to run at a higher rpm than allowed, those rpm's will then be reduced and used to push you further per revolution. Be careful not to overprop, and don't buy them until you have tested them and are happy with them!

 

[fbait4562]

Re: correct prop size???

Thanks for the input. My tachs are reading 5750 at max. The boat weight is approx 7500lbs, 31' legnth and it is a Jupiter 31 Cuddy. Appreciate any other advice.

 

[Tracy Coleman]

Re: correct prop size???

jupitercatcher<br />You are perfect on top rpm. Are they aluminum or stainless?<br />Backfire

 

[Dhadley]

Re: correct prop size???

Jupitercatcher -- I may have some Stiletto's and Turbo's that I can get you a good deal on especially if you are looking for a four blade set. We have some "once tested" props that are perfect but have been on a boat for testing. <br /><br />You can e-mail me at dhadley50@aol.com if you like.<br /><br />Good luck!

 

[fbait4562]

Re: correct prop size???

The props I'm using are stainless. They are the same ones I was using on Merc 225 EFI which maxed out at 5500 RPM. they worked great and topped the boat out at 55MPH.