Should I buy a 2 blade prop?
 

I have a chance to buy a used OMC brand SS 2 blade prop, 13.5"x25", and need advice. I have a Donzi 16 with a 302 HO Ford, 200 HP, Cobra drive @ 1.58 ratio. Trimmed for speed I max out at GPS 59.4 MPH @ 4800 RPM using a 14.25"x21" SST tuned by DAH. Do you guys think I will achieve any performance gain from this prop? Any guess if the max RPM I can pull will decrease (4" higher pitch) or remain the same (3/4" smaller diameter)?

Thanks in advance for any good advice and experience you can offer, JC

>>>No, really, its not about how fast can I get this little boat to go. OK, well maybe it is!!!!!

On paper you will lose about 400 rpm but that is without looking at the propeller so the estimate really doesn't hold any water.

Your slip is low which opts for less blades. But, your hull can use some bow lift and the 3rd blade is a advantage there.

Unfortunately testing is the only way to know. I like the 3 blade option better but it would sure be fun to try the 2 blade.

Brett

Hello John,

I feel the 2 blade will be a mistake. The diameter is too small to handle the Cobra drive and the power. to weight ratio. Your slip numbers well be thru the roof, and the boat will handle poorly. I agree with those recommending 3 and even small 4 blades.

Thanks,

Thom

Thanks guys. My wife and I are recently retired and its kinda weird having no money come in except for the social security. So currently my play money is in short supply. I'm trying to find that last 0.6 MPH (to get me to 60 MPH) and I was hoping this prop would do it.

I appreciate the input.

John C