39 foot cat
12,000 lbs
Running small pulleys 850-900 HP
Arneson 8's set up for Merc SM #6 props
Ratio 1 to 1:32

What would be the expert's calculation for pitch and diameter for a set of:

4 blades

5 blades

I have no idea.
but you could try using a prop calculator and see what you get, Mercurys site has one.good luck,sorry we could not help.

There are a few members here that would probably have a idea and are not even prop experts.

Expresscat39,

Do you have dyno runs on the motors?

What is the peak torque rpm and peak HP rpm?

Based on the numbers you gave above I would expect a top speed of about 110. I need to know what rpm the motors will run at WOT to give you a recommendation on a prop.

Matt

why does it seem impossible to find prices and info on Props for #6 drives? Both 4 and 5 seems hard to find out anything about

The #6 drives are becoming more popular. We deal with more and more of them all the time. We work with a number of race boats and high horsepower personal boats with #6 drives so we have experience with them. If you have any questions about a specific application please give us a call.

There are a few more variables with the #6 drive props than there are with Bravo drive props that have to be taken into account. The price of the props for the #6 drives is more than the price for the Bravo drives.

If you are interested in prices for #6 drives give us a call and we can help you out.

Matt

We have the curves.

900+ lbs torque @ 6000 RPM.