Greetings another hassel,
I have no idea. Just a buzzword I heard and thought it was cool. I first heard it from Fr. Frank who suggested my Seafari would perform best with a stern lifting prop. He's probably rigged more hi-performance boats than I'll ever see, so I believe him. I'm guessing he'll chime in after seeing my butchering of this very hydro-dynamic subject.
In simple terms some boats ride better when their bow is down a bit (deep-V)and some only want the aft in the water (bass boat or flats boat). Some boats are just bow heavy and some are stern heavy. Differences in propellers can make them achieve their maximum capabilities. A bow heavy boat will just plow water below cruising rpm if it can't rise to say 3-5 degrees off level. By getting the bow up a bit it will reduce drag and enable it to get on plane at lower rpms, thereby increasing efficiency. If a boat has too much weight aft, the rear of the boat is pushing water and needs a means to level it out to get on plane. This can be done with a hydrofoil, trim tabs or with a stern lifting prop.
In very general terms, a propeller that has more rounded blade tips and cupping at the front of blade will tend to have bow lifting characteristics, while those with a straighter back edge thus a sharper blade tip (semi-cleaver)and cupping on the back of the blade may have more stern lifting capabilities. AS to the why? part, well that's more hydrodynamic physics than I can wrap my meager mind around.
Do a search for "stern lifting propellers and you'll likely find a boston whaler site called continuouswave.com There is a pretty spirited semi-technical discussion there among engineers and boatsmen, certainly far more depth than I can offer.
Still others will say there is no such thing as a stern lifting prop. If not, there are some great marketeers out there...
