My Honda 40hp twins have 11 1/4 x 13 stamped on the three-bladed aluminum props. I only recently obtained the boat...
I've tested it to 28mph at 5800-5900rpm with about 800lbs (quick estimate) loaded aboard. It was very smooth, though loud and obviously I didn't want to push it further. The ocean was glass that day.
5,000rpm is a sweet spot for my boat compared to >5500, though I'm usually running at 4500rpm or less of course.
I recently ordered replacements for a spare and they incorrectly sent me a 11.1 x 13 prop which is, suprisingly, very different in shape. I'm curious about it, it's a Honda prop, while the ones I have on now don't appear to be the Honda name brand.
I'd like to move to stainless eventually though I am in no hurry.
Mike