Thanks. Yes, I found the Hydrus 13" prop on the Evinrude website, with that same part number.
There was also a Hydrus 14 x11:
http://shop.evinrude.com/product/598004 ... ntoon_11RH
OK, so that must be the difference. You are using pontoon props. EZ and myself are using standard props, so that is why our results correlate.
Do you think there is a big advantage to the pontoon props? The write-up on the Evinride website says that they are designed for maximum thrust and stability, for pontoon boats and work boats.
I'm happy with what I experienced today with the standard 13.75 x 13 prop. I did some s-turns at WOT, and it felt good. Accelerating from a dead stop, it seemed to bite well, although I didn't try a hole-shot. Coming into port, I had to shift into reverse to avoid a kid in a dinghy who was stuck in irons, and that maneuver went well. I was traveling at about 4 kts, and was able to stop quickly.
But if the pontoon prop provides a big improvement, I may consider it.