Same prop, two different outcomes

I bought a 2001 bass tracker 175 xt with the 50 hp 2 stroke Mercury on it, when I bought it, it had a Solas Amita 11"x15p aluminum prop on it. Motor runs good, but turns 46-4800rpm. So a guy I work with said he had tracker 165 with the 40 on it that was the same prop spline. So we decide to take his Apollo 993407 10 3/8"x14p stainless try on my boat. Worked flawless, rpm 5500, felt good taking off, turning and all. So I come home and order the same prop and hub kit he has. 993407 prop and 114 xhs hub kit. So we put my prop on and take it for test run. Same amount of fuel and gear, and my rpm will pull 5000, no higher at w.o.t. but with his prop we got 32 out of it and mine got 32.9. my question is, are these props pretty consistent from one to the other? I can't figure out why rpm dropped and speed went up with two of the same prop.

Sounds like your new prop had a better bite on the water. Could be the other prop you used had some nicks or dings on the edge changing the water flow enough to give differences.

also could be water was smoother or rougher , wind from different direction meaning the conditions and weather !!! has a lot to do with it also !!!

Very true. A little chop on the water certainly can increase your top speed

I also would agree with both explanations above. 0.9 MPH and 500 RPMs is easily credited to wind, water conditions, and smoothness (both on the edges and surface) of the new prop.

The blades on his prop are splayed out some from use, less cup I guess would be the correct term. If he had a stainless prop and you ordered a stainless prop, you wouldn't see the variation unless his was damaged.

Both of our props are stainless, same everything,i ordered exactly what he had, that's why I'm puzzled. Different water conditions might be the culprit, I'm gonna give it another go Friday maybe.

I misread your original post. I saw aluminum prop but see now that was your original prop. His prop may still have some of the cup gone compared to yours.

have your buddy try your new prop on his boat