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Old 04-29-2008 | 11:53 AM
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Default Prop Help

Guys trying to help a frend with a smaller boat, he has a 21 footer and is looking to upgrade his prop.

He currently has a 13.5 x 23 pitch prop and wants to go to a 14.5 or 15 diameter but needs to know where that would be as an equivelent pitch.

His hope is the bigger diameter will help on the bottom end with out loosing top speed. Its a 3400 lb boat with a merc 5.7 ( 210 HP) and Alpha 1 drive. He it running aboiut 52-53 MPH at 5500 RPM now.

Last edited by JBoat; 04-29-2008 at 11:55 AM.
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Old 04-29-2008 | 11:59 AM
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21P is what most 5.7L 21' boats run.
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Old 04-29-2008 | 01:13 PM
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21P by what diameter ? If you know off hand.
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Old 04-29-2008 | 05:33 PM
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I would say max of 14.25" on a 21 ft. boat.

Julie
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Old 04-29-2008 | 07:34 PM
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I don't think he can run that much diameter on an Alpha drive.
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