Why squirt up?

Discussion in 'Jet Drives' started by Tiny Turnip, Sep 15, 2014.

  1. Tiny Turnip
    Joined: Mar 2008
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    Tiny Turnip Senior Member

    Why is it that the exhausted cooling water is squirted up in the air like a fountain on some jet skis, rather than just down into the water? Is it just flamboyant expression in the design, or is there something more? Just curious...
     
  2. baeckmo
    Joined: Jun 2009
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    baeckmo Hydrodynamics

    Simple check that the engine cooling is working, just analog to outboards.
     
  3. PAR
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    PAR Yacht Designer/Builder

    It's more a phallic thing than any practical purpose. Some might argue that you can see the stream, but there's a lots of ways to do this without an arc of "pee" through the air. Purely a styling exercise that caught on as cool.
     
  4. rasorinc
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    rasorinc Senior Member

    perfect answer Par
     
  5. whitepointer23

    whitepointer23 Previous Member

    A few of them could line up and see who squirts the highest.
     
  6. waikikin
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    waikikin Senior Member

    Even closer to the point, I'm sure Dr Sigmund would have a view.
     
  7. Tiny Turnip
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    Tiny Turnip Senior Member

    Thanks for the replies, Baekmo, PAR - much as I feared.

    Brendan, your idea for a Jetski p**sing contest is inspired - I should think Red Bull will be on for sponsorship...
     
  8. dinoa
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    dinoa Senior Member

    Improves visibility too.
     
  9. kerosene
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    kerosene Senior Member

    I always thought it was a safety feature to make small quick craft more visible
     
  10. jehardiman
    Joined: Aug 2004
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    jehardiman Senior Member

    I thought is was so the AGM-114's would always lock.
     
  11. slow fred
    Joined: Feb 2011
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    slow fred Junior Member

    It always better to squirt up, especially when you get my age.
     
  12. WestVanHan
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    WestVanHan Not a Senior Member

    AFAIK it's only Yamahas that do it..a tell tale for the cooling water.

    My Supercharged Sea Doos and Honda FX15 turbo don't do it, a friend's 300hp Kawasaki doesn't.
     
  13. gonzo
    Joined: Aug 2002
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    gonzo Senior Member

    It is called a "rooster tail"; the equivalent to straight pipes on a motorcycle.
     
  14. Waverunner Eagl
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    Waverunner Eagl Junior Member

    That is a safety feature on yamaha ski's. The rooster tail is often visible when the ski is not. This is most notable in the evening when you get a lot of glare off the lake from the lower sun.

    It's actually not an indicator that the cooling system is working. The rooster tail water comes directly off the jet pump, not off the cooling system. Many older skis do have an indicator, but it is plumbed in after the exhaust pipe and is usually only a small stream. The newer skis mostly just have temperature senders in the head
     

  15. whitepointer23

    whitepointer23 Previous Member

    Old thread but I have a new target for the missiles. Several times I have been working peacefully on my ketch when bloody wake boats start roaring past with their 3 ft wakes and they do that all day with loudspeakers belting out some crap that is supposed to be music. Now when jetski flies past I don't even notice. :D.
     
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