Two Data Points, Priop Suggestion?

Chris1956

Supreme Mariner
Joined
Mar 25, 2004
Messages
28,188
I have two data points, and want to choose the best prop for fuel economy.

The boat is a '98 21 Seaswirl Dual Console with a '98 150V6 Carb'd Johnny. The boat is decidedly bow heavy, but with that Looper has great hole shot.

It came with a standard OMC Alum. prop of 17" pitch. I get 5200RPM and 39.2MPH (GPS) at WOT.

I put on a 19" Pitch standard Merc/Michigan alum prop and got 4500 RPM and 39.9 MPH at WOT. The OMC prop allowed more trim w/o slip however.

The motor is mounted in the top standard bracket holes. (No jackplate), and has the AV plate showing at planing speed. It might be a bit high, but has good water pressure.

I plan to run the Merc Prop to see how it performs. The 4500 RPM at WOT is the minimum WOT operating RPM, according to the OEM Service manual.

I would like a prop suggestion to give more bow lift. And top speed (economy)
 
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