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Thread: Prop efficiency

  1. #1
    mikelytle1077's Avatar
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    Prop efficiency

    Has anyone noticed after a certain rpm range your prop feels like its no longer moving enough water ? I currently have a 14/19 at 8600 rpm I have a 15/20 on the way just feels like the 14/19 can't keep up with the revs


  2. #2
    Vikesfan's Avatar
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    Sounds like you need that 15/20. You can bend your 14/19 to get your RPM's right, but the 15/20 should be much closer.

  3. #3
    AtoMIC_OraNGE greenbullet's Avatar
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    the 15/20 is what you need.. the root angle of the 14/19 isnt the same as the 15/20 .. you put the wordds right in your mouth.. the prop feels like it isnt moving water anymore ....... you need a 15/20+1 mm and your good maybe 1.5 depends on your ski and you

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    h2jim's Avatar
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    No way a 14/19 is enough. What are your numbers? Afrs, rpms and speed.

  5. #5
    I have fairly high speed data logging on my ski with GPS support. I find that up top my ski pulls right at 123 RPM per MPH With that sort of data logging capability, it gets fairly easy to to sort this stuff out. Without logging, it gets fairly tough.

    FYI, these boats get less prop slip the faster that the speed is. I never really expected to find that. At 50 MPH it is more like 160 RPM per MPH.

    Have fun tuning

    Andy

  6. #6
    Boost-A-Holic's Avatar
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    what you feel is a 3-seater. That fat ass is dragging in the water... your doomed bro.

    Marco from Trapoja told me this

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  7. #7
    mikelytle1077's Avatar
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    Quote Originally Posted by h2jim View Post
    No way a 14/19 is enough. What are your numbers? Afrs, rpms and speed.
    currently speed is 77.0 @ 8550-8600 afrs are 11.7-11.9 i can feel the strong pull around 7500-8300 after that it just flat like its out of prop. hopefully the 15/20 will help i want a 80mph 3 seater

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