About 6 years ago I bought a used 13x15 three blade prop because I was very unhappy with my 13x7 two blade sailorman prop that came with the boat. I thought at the time that it(the new prop)was probably over pitched but I put it on anyway. The difference was apparent the first time I put it in gear. But it vibrated and I couldn't get to full engine speed so I throttled back a little and did well enough. Last winter I took it off and had it re-pitched and reconditioned. It was in bad shape as far as pitch was concerned. one blade was at 15 another was 14+1/2 and the third was 15+1/2. Now they are all at 13 and the man who did the work said that for a 40 year old prop it was in excellant condition. We splashed the boat today and were pleased to find that we have reduced prop walk and vibration, an increase in top speed from 5.5 to about 6kts. and a somewhat slower speed at idle, down around 1.5 all on the gps on the river at high tide so the current was not significant.I had determined that the prop was out of shape just with a tape measure but I didn't realize it would make so much difference.