Just thought i'd share my experience here. 1998 18' bowrider, 3.0L 4 cylinder, Alpha One Gen II, family of 4, beach gear, full tank of gas (30 gallons). Prior prop was a Michigan Wheel 21 pitch 3 blade aluminum in excellent condition, boat was pretty slow to get on plan, wouldn't pull me up on a wakeboard (it wouldn't plane), and top speed was 38mph at 4600rpm but if I trimmed out all the way it would porpoise. I purchased a Solas Amita 4 blade 19 pitch, with the same load as before the boat quickly gets on plane at 17mph and holds it, top speed is 38mph at 4800rpm (didn't stay there for more than a couple seconds!), and it no longer porpoises.. Also, in turns it is much more "on track", idle speed in gear is slower and it's much more controllable at idle speeds, and I must say, that 4th blade makes the propulsion as smooth as a Cadillac. Haven't had a chance to try wakeboarding behind it yet but so far I am VERY impressed with the improvement in performance.
