How much difference does diameter make?

[brusk]

Ok since I'm looking for a prop and I understand a little about the pitch I need to go down a little on pitch. Looking at props I see alot of 14" props for my Evinrude. I currently have a 14 1/2. How much of a difference does this make? If i'm looking for more out of the hole does a smaller or bigger prop help with take off.

 

[steelespike]

Re: How much difference does diameter make?

Diameter is a secondfary consideration mostly to be sure it will fit in the space.
If a prop is intended for your application the diameter will follow.
Usually diameter is a function of the design Only time to consider diameter is if the difference is around an inch assuming your staying with a reasonable pitch range of your present prop.
Generally as pitch goes up diameter goes down as pitch goes down diameter goes up.

 

[jeffnick]

Re: How much difference does diameter make?

Standard props normally are available in 2" pitch increments. Going less than 2" isn't usually significant. Don't worry about the diameter - go down in pitch for a better hole shot but less top end.

There are some props designed for non-performance boats that have large diameters which perform better at low to midrange and give better mpg there at the expense of top end.

Venting can also help your hole shot. I'm not recommending you do it yourself, or even have it done...maybe you can find one that is already vented.

I've had good luck with these guys.
http://turningpointpropellers.com/propellers_101_cm.htm