how to pick the right prop?15+17 or 14+19 ,14+21 ss or coped?

[MR GIBBS]

i have a 15+17 ss prop on a 200 hp evinrude wot is 5300 rpm at38 to 41 mph whould a14+19 or a14+21 ss cuped increase top end and more bite the 15+17 seems to gavate when trimed up the boat is a 21 deep v 3400lbs total thank you what do the numbers mean on the prop

 

[wilde1j]

Re: how to pick the right prop?15+17 or 14+19 ,14+21 ss or coped?

Most OMC v4 and V6 outboards want to run 5500 to 6000 RPM WOT. If you're now running a 15X17" prop which maxes at 5300, you want a lower, not higher pitch. Each 1" pitch reduction will gain around 150 RPM, so you should be looking at a 15X15" prop, not a 15/21". Cupping slightly reduces the RPM gain, but is helpful in preventing cavitation.<br /><br />The first number is the prop diameter in inches, the second is the pitch, also in inches. Pictch is how far a prop would advance (theoretically, with no slippage) in a single complete rotation (360 degrees).

 

[RJS]

Re: how to pick the right prop?15+17 or 14+19 ,14+21 ss or coped?

Wildone,<br /><br />I also have a 21 footer with a Merc 200 EFI. It's a 3 blade prop with a pitch of 17. It turns ~5200 RPMs. Max recommended is 5800 RPMS. I would like to increase hole shot and cruising speed. How would a 4 blade prop fit into the equation.<br /><br />THanks

 

[Spidybot]

Re: how to pick the right prop?15+17 or 14+19 ,14+21 ss or coped?

Hi Guys,<br /><br />Look here http://www.iboats.com/cgi-bin/ubb/ultimatebb.cgi?ubb=get_topic;f=17;t=015097 and pick your desired link.<br /><br />Lotsa good info...