3 blade to 4 blade - questions?

[alwhite00]

I have a 86 Seville 21 MC - 260/Alpha 1 with a 14.25 X 21 3 blade aluminum prop on it right now. Tops out at 40mph @4,500RPM and I cruise around 25mph @ 3,300-3,400 or so.

What could I expect switching to a 4 blade prop? (same pitch & diameter if available) Or do I need a different pitch?

Wouldn't mind getting out of the hole a little quicker but don't want to throw money away either.

Thanks for any comments.


LK

 

[CV-23]

You will get more stern lift and on plane faster but may loose some top end speed. You'll have to also drop two pitch sizes to keep your rpms up.....21 to 19P if you stay aluminum. Mercury makes a good one, Mike.

 

[alwhite00]

Thanks for the input - Even if I go stainless I should drop 2 pitch sizes? Just wanted to clarify.

LK

 

[sr330daguy]

Good info here........www.propgods.com