| | new prop update for pontoon 11p to 9p
I had and 11 pitch prop and was only reading 5300 for my Yamaha f70 (5300-6300 rpms). My top speed was 20mph with just me. I just got a 9 pitch and my rpms went up to 5800 and kept my mph 20 mph using gps. the performance is a night and day difference. with about 300 pounds more of people it drops to 5700 and 18mph. turns so much better while keeping my mph at 17 instead of dropping down 13. last prop I had to have it trimmed up above middle now its down past half way and I can actually feel it hook up better doing so. I'm on the lowest hole for the engine.
Overall I'm happy with the 9p mercury calc. says 6% slip compared to I think it was 16%. would still love to get up to 6300rpms. but according to mercury calculator I would only gain 2 mph with a 9p.
I would love to try a mercury spitfire but they only go down to 10 pitch but diameter is slightly less. You think it would help or hurt top speed?