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Old 09-13-2016, 06:56 PM   #2
DavidM
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City: Litchfield, Ct
Join Date: Aug 2012
Posts: 6,785
Hard to say. One way to know is to join boatdiesel and use their prop calculator. Another way is to ask the prop shop where you bought your new prop if you bought it from one.


A rough rule of thumb is that each inch of pitch change results in 100 rpm change. But a 5 inch up pitch change plus 4 to 3 down blade change is more than any rule of thumb can handle.


My guess is less than 2,400. Going from 4 to 3 blades won't offset 5 inches of pitch.


David
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