Gregg, it is for Jim's 115 HP Merc.
Don, on the national Glastron site, I did an experiment addressing the subject you mentioned, namely, taking identical props, in my case, two new 22" pitch OMC Rakers, and sharpening the blades on one of them, and leaving the another stock, and then testing them on secret Lake WBL. The one with the sharpened blades was a fraction of a MPH slower, but there are so many variables in a test run that the best conclusion to draw is that sharpening did not seem to help.
I sharpened just the tips. I need to gradually taper the thinning over a large area and that will be another winter project. Then the testing of 5 props at secret Lake WBL this spring.
Performance prop shops that rework props for really fast boats (and the faster the boat, the more worth while to have a prop reworked) check for balance of the blades and the correct pitch on all the blades, just to bring them up to factory standards as they should be sold. But reading an article by the owner of DAH prop shop, the factory quality standards are low, with many factory props lacking on these basic points. Balance is important for the long life of the engine and smoothness.
Then a good prop man knows how to improve the performance by reshaping, thinning, and taking off material in the right places (Allison cut, Bullet cut). I do not claim to know anything about this level, but have heard Steve Smith in Kentucky, the Twin Cities Performance Prop man Dave, and the DAH owner taking about how they can do things to improve the speed simply because they have worked on, say, a Laser II, many times and know the tricks.
But we are still talking only a mile or two of performance gains. Only one of many things to increase speed.
