Dual Prop Pitch vs WOT rpm?

[harringtondav]

I learned on this forum the solid rule for single props. +- an inch of prop pitch = -+ 200 WOT rpm. The rule has worked spot on for me, and I share it with others.
I occasionally get prop pitch questions from DP drive owners. I pass on an answer because I don't know.
So, is the pitch/WOT rpm rule different for DP drives?
Thanks, Dave

 

[jimmbo]

The same Rule should apply, but it would be best if they were to contact Mercury or Volvo so there is no Doubt

 

[Scott Danforth]

with VP, there are about a dozen series of DP props, many with differing hub and blade designs. They have a full manual just on props.

I know there are differing prop types for Mercruiser Bravos as well

ballpark rule of thumb is about 300 +/-100 RPM for prop jump based on my limited experience with the A, P, and C series I noted that speed change is also different in salt water vs fresh water

 

[bajaman123]

Well...the "rule" is really ONLY applicable for comparing one OF THE SAME PROP to another. The "rule" goes out the window if the model of the prop changes, number of blades, diameter, style, etc change.

 

[jimmbo]

The number of Prop Options is quite Limited for the Volvo DuoProp, and the Mercrusier 3

 

[boscoe99]

When you use the term DP are you talking about contra rotating propellers like Suzuki, Yamaha and Mercury use on some models?

 

[Scott Danforth]

in this case, since the OP has a Volvo Penta with duo-prop drive.