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prop info

Discussion in 'Props, Shafts & Seals' started by Vandalay, Sep 25, 2007.

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  1. Vandalay, Sep 25, 2007
    #1
    Vandalay

    Vandalay New Member

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    I'm being told that a 40" / 40 pitch prop will perform roughly the same as a 42" / 37 pitch.

    they will be fitted on a 96' Westship.

    anyone know if this is correct or how I can verify?

    thanks
  2. AMG, Sep 25, 2007
    #2
    AMG

    AMG YF Moderator

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    Roughly yes, but you shouldnt mix if this was the idea...
  3. Loren Schweizer, Sep 25, 2007
    #3
    Loren Schweizer

    Loren Schweizer YF Associate Writer

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    Utilizing no small amount of SWAG, I'd venture that if the 40 X 40 prop worked, that 42 X 37 would 'over prop' the boat.
    The old rule of thumb was that an inch of diameter was worth 2-3 inches of pitch, or thereabouts.
  4. Vandalay, Sep 25, 2007
    #4
    Vandalay

    Vandalay New Member

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    right, we have to replace both props. the old damaged props were the 42/37and a pair of 40/40 were offered to us and i was told they should perform nearly the same.
  5. Vandalay, Sep 25, 2007
    #5
    Vandalay

    Vandalay New Member

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    the original props were the 42 x 37 and they were damaged. a set of 40 x 40 were found and the dealer tells me they should perform about the same. i understand that the larger the prop the more "pull" and the pitch is more about speed. we were experiencing some overheating issues prior to engine max rpm so i want to make sure that i correct for that this time around. any thoughts?
  6. K1W1, Sep 26, 2007
    #6
    K1W1

    K1W1 Senior Member

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    Hi,

    Your engine overheating at full power might not be so related to Prop size that resizing will fix it permanently.

    Depending upon what you have for power and depending if this is a recent problem or it has done this since new there can be a number of reasons why they get hot.

    The condition of the Air System on the engines, the Engine room ventilation, exhaust back pressure can all play a role in giving you an overheat at full power.
  7. CaptPKilbride, Sep 26, 2007
    #7
    CaptPKilbride

    CaptPKilbride Senior Member

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    And, if your engines are still covered by a warranty, or extended warranty, you may need to have a manufacturers rep aboard for a new sea trial to ensure warranty is not voided by the new props.