muskyfvr - 2/21/2011 10:40 PM

I have a 1850 Fishhawk with a 135 Optimax with a 14 1/2 X19" prop.
I would like to get a stainless steel prop. Should I stay with the 19" prop.
Or go to a 13 3/4 X 17" prop. I'm told that a 17" will give me a good hole
shot but slower speed. Is this correct? Thanks for any help.



Hiya,

In the situation you are working with, going down 3/4" in diameter will help keep your rpms up when you switch to steel. So in your case, you would see roughly a 300 - 500 RPM drop due to a switch to steel in the same pitch, but roughly a 300 RPM gain for reducing diameter (every 1/4" is roughly 100 RPMs). Should almost come out in a wash if you stayed 19 pitch, but there is a point of diminishing returns in this and performance goes down significantly if you get too much pitch for the motor. Going to 17 pitch might reduce your overall speed a little (very little... I think), but your hole shot would be great as compared.

In the aluminum prop, chances are you are not getting the full 19 inches of pitch that the prop is marked at anyway...reason for this is due to how much aluminum will flex, and aluminum props slip quite significantly, reducing the efficiency of the motor (result, wasted gas) While under load, that 19 pitch aluminum is probably running more along the lines of a strong 17 pitch anyway due to the flex.

I would say going to the 17 pitch in steel is a good move. The steel will not flex anywhere near as much which means the prop will be running at a true 17 pitch. With most steel props, there is a designed cupping on the trailing edge and fin tip, which will essentially make the prop hook up more, which reduces the amount of slip in the prop with the water. It will lift the entire boat out of the water more, and the prop will not ventilate anywhere near as much as compared to an aluminum prop in a turn. A cupped prop in 17 pitch would then act more like an uncupped 18 pitch. The other benefit of running steel....you can usually raise your motor up off the transom a couple of holes...especially if you find a prop that hooks up really well in all RPM ranges.

The best thing you can do, though, is find a dealer that has a demo prop program (demo props in many cases I have experienced are blue), try different brands, diameters and pitches, and head to the lake for a day of testing. One prop will stick out above the rest in terms of speed, hole-shot and overall handling. The process can get tedious, but well worth the time, since the prop that performs the best is the most efficient prop as well.

Good luck, and I hope this helps you out some..

Steve