Xpress HD16DB Prop saga

So, here's a good head scratcher. Story starts with a 16 foot with a 40 Yamaha 4 stroke. I put on an REB3 12P last year and it ran great however I had to trim out down to keep from porpoising. RPM's were at 5800-5900 with lightest load. I was happy with that.

Banged it up over the hunting season and decided to buy a new one. Went with an NREB 12P. It's the same as the REB just .25" bigger in diameter. This allowed me to go up one hole on the trim and still not bounce. This is a good thing. Now the trim is just about neutral. However, the RPM's jumped up to the tune of 6100+ sometimes hitting the REV limiter. Get your head scratching apparatus ready.

I went up to a NREB3 13P. Should have brought it down to about 5800-5900, right? Max WOT with the 13P is 5400ish now. Installed a jackplate to get some more rpm. 5550 max, with the lightest load. Speed went down as well, lost 2 mph. Had the 13P gauged by the local prop man. It's true.

Now I'm running the 12P and constantly watching my tach. Is there a better model prop that would work better with my rig? Anybody ever see rpm's change so much with one pitch? Any advice or direction is greatly appreciated!!

Repair the original prop?


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I bought the original REB3 second hand and it had 2 bent blades. I know metal weakens the more you bend it and decided not to invest in it any further. Plus I'd have to trim it down so far (plowing) just to keep the boat from porpoising.