trolling speed

[Bduck]

I have a Yamaha 9.9 high thrust that came stock with a 3 blade 7 pitch prop. For a while I was considering changing prop opting for slower speed but procrastinated until 2knots Alan contacted me he did change his. His motor is also the Yamaha 9.9 high thrust. I followed what he did with good results of slower speed. We both went to a 4 blade 10"x 5 pitch dropping speed into the 0.7 range. Also what changed was RPM's going higher for example if using 1.6 than what it was with previous prop. It doesn't hurt anything but it does take some getting use to hearing the motor rev a little higher tune.