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bnkellogg
08-10-2009, 02:01 PM
"I have a new pontoon boat (Bennington Sedona 20 ft) that has a 4 stroke T60 Yamaha engine. A 13.75 diameter prop with a 11 pitch produces 20 mph and 6300 RPM.
I tried a 14 diameter with 13 pitch and the speed drops to 19mph but the RPM drops to 4700.

Manufacturer recommends 5000 to 6000 RPM. I would like to find a 12 inch pitch prop that would fit the motor to come up with an RPM in the middle. Any suggestions?


Barry Kellogg

barrykellogg@gmail.com ("")"

texas_larry
08-12-2009, 02:40 PM
A good prop shop should be able to "cup" your 11" prop and give you what you are looking for.

Cliff C
08-12-2009, 03:36 PM
"Hello Barr,

the rule of thumb when selecting a prop is for every 2 degrees you gain or loose 400 rpm (only a guide line) but something do sent seem right the diameter make little difference when you test use gps for speed or forget about it all together and are you sure about the degree's??"

texas_larry
08-12-2009, 04:04 PM
"Cliff's correct that 2 inches of pitch should not make that much difference in RPM. Are both props that you tried made of the same material, i.e. aluminum or stainless?"