08-27-2019, 01:29 PM
I have a 2003 38 Open w/450 Cummins as well but with 24x28 3 blade nibrals w/full cup.. At 2100 I'm doing 21.5knots. At 2200 23-23.5knots and wide open, 2600, I'm at 27-28 knots. Very similar to your analysis. Boat came with 3 blade but have heard several owners switching to 4 blade. Was told they are smoother, less vibration, although at all speeds mine feels smooth. Not sure what the real difference is. M2C


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