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Opinions for Underwater Exhaust Deflectors

Discussion in 'Technical Discussion' started by comship, Dec 8, 2007.

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  1. comship, Dec 11, 2007
    #41
    comship

    comship Senior Member

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    Not again, the only thing I said was
    and it was going to Garry. It was just a reference to the term he used. I told him that the right term for <<ventury>> is the exhaust thrust slot and together with the WET EXHAUST SYSTEM was invented by Cpt. George Vonwidmann. I have never said that these deflectors are Vonwidmann products
  2. comship, Dec 11, 2007
    #42
    comship

    comship Senior Member

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    The arnesson surface drives because of their nature are operating inside the turbulent flow of the water , which is stronger near the sea surface( I am refering to the boundary water layer). Thus, always in my opinion, devices like that wouldn't be necessary for surface drives.
  3. comship, Dec 11, 2007
    #43
    comship

    comship Senior Member

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    Anyway I want to ask sorry from Yacht Forums and its Members, as the temper lost because of misunderstanding
  4. vonwidmann, Sep 27, 2010
    #44
    vonwidmann

    vonwidmann New Member

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    Clearing up a mis-understanding

    To clear up some mis-understanding as to my design the statement of only being used on sport fish yachts is not really true . It is true we started in the sport fish market but have moved on to the large motor yacht market.
    Our first large yacht was the Broward 105' back in 2001 and our lastest is the new Palmer Johnson 171 . Our designs are also being desiged into the new Palmer Johnson 210' and the new Trinity TO-61 with the new MTU M-93L 20V4000 Series @ 5780 hp. The 171 Palmer Johnson yachts have the MTU 16V4000 M-93L @ 4600 hp .

    Over the years we have done a number of re-fits from 98 to 130'

    Hope this clears this miss-understanding up.

    Link Removed

    Attached Files:

  5. K1W1, Sep 27, 2010
    #45
    K1W1

    K1W1 Senior Member

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    Hi,

    I have just driven 1780 Km straight and am rather done in, it does bring a smile to my face and perk me up however to read such a post as No 45 from our esteemed leader.

    Keep up the good work Carl.
  6. John Oldrino, Oct 5, 2016
    #46
    John Oldrino

    John Oldrino New Member

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    Punta del Este
    Hi:
    We are refitting an antago 22.5 meters and need to upgrade the underwater exhaust because of vibration.
    Could you please send more pictures or info regarding this issue? Also if you have a lateral picture to see the shape.
  7. Capt J, Oct 5, 2016
    #47
    Capt J

    Capt J Senior Member

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    Some Lazzara's experience terrible cavitation getting on plane and vibration from the cavitation they put a 1" thick lip around the underwater exhaust to direct it away from the props and it helps considerably.
  8. Pascal, Oct 6, 2016
    #48
    Pascal

    Pascal Senior Member

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    Correct. On the 84 I run now, you have to accelerate gradually to avoid th exhaust being sucked in an causing cavitation. Boat has the bigger C32 and will be on plane at 1500 in a very short time but if you are heavy handed the cavitation will be horrendous.

    During sea trial, the management company "rent a capt." Was one of those heavy handed sport fish jock who just pushed the throttles forward. Had to back off and then be told to try it again slowly. It's kind of like stepping hard on th gas of powerful car with traction control off. You ll just spin the tires.

    I was told by people familiar with the design and who work at the factory that They tweaked the design adding a fence and a lip to divert the exhaust. It's hard to see in th pic but the fence is about 4" tall and extends aft about 4' or so

    Attached Files:

    Last edited: Oct 6, 2016
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