[Fr. Frank]

You've gotten some good advice here. One more thing I'd like to add: Even when you've think you've found "THE" prop, don't be afraid to keep testing and experimenting.

I ran a 17" Mirage on my V6 200 hp Mercury on the back of my 20' Seafari, and was amazed at how much better it was than the stainless 19"P Michigan I got with the motor. I tried a bunch of props before finding the Mirage. I went from 5500 rpms at 38 mph with the Michigan to 5750 rpms at 43 mph with the Mirage.

But then one day the owner of the local Mercury dealership offer to let me try his 4 blade 15x17" PowerTech he was running on his 19' Aquasport cuddy with a 200 efi Merc. That was even more amazing! I ran 5600 rpms at 45 mph, but minimum plane went from 18 mph down to 13 mph, and time to plane went from 7-8 seconds down to 5 seconds.

So I called PowerTech, and spoke with an engineer, and sent him photos of my hull, along with actual weight and balance data for normal usage, nose-cone design, etcetera; and they made me a custom one-off 15.25" diameter x 16.5" pitch 3 blade with a very aggressive rake progression on the trailing 1/3 of the blade and heavy cupping. It cost me a little over $700.

My new top speed was 53 mph at 6050 rpms with 10 gallons of fuel and one 200 lb driver, at 40F into a 7-8 mph headwind with a light chop. Time to plane was still 5 seconds, or just under, and minimum planing speed was now 14-15 mph.

I could have just stopped experimenting with the Mirage. But the Michigan I started with was "in the zone" for rpms, speed, and all that stuff. I just knew I could do better. I gained 15 mph in top speed, reduced my minimum planing speed by 4 mph, and reduced my time to plane by 2 seconds or more. [And the incidence of rake progression and cupping on the new prop threw a 25' high rooster tail at 50 mph :-) ]

Okay, it did cost me over $700. Worth every penny.