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Propeller Clearance

Discussion in 'Props, Shafts & Seals' started by golden_fox, Sep 9, 2007.

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  1. golden_fox

    golden_fox New Member

    Joined:
    Sep 25, 2006
    Messages:
    46
    Location:
    Maldives
    Hi Everyone!

    Can anyone give me an indication as to what is a recommended minimum clearance between the propeller blade tip and the bottom of hull? And if the propeller is in a tunnel, does this vary?

    Thanks a lot and appreciate any input.
  2. CODOG

    CODOG Senior Member

    Joined:
    Jan 25, 2007
    Messages:
    399
    Location:
    Bournemouth, southern England
    I would suggest a generalised tip clearance of 1/6th of prop diameter, for both a tunnel and non-tunnel application. Also, I'd use the same ratio of clearance as a minimum from trailing edge of prop blades to leading edge of rudders.
    I've seen successful installations with more and less clearance, but the above is a good starting point. Too little clearance is worse than too much usually.
    Are you buying a prop / props off the shelf or purpose made ? Is this a tunnel application ?
  3. Booker

    Booker New Member

    Joined:
    Sep 25, 2007
    Messages:
    1
    Location:
    New Orleans
    15% of prop diameter is a good rule of thumb.