low rpm diesel

Discussion in 'Propulsion' started by ron17571, Jan 16, 2005.

  1. ron17571
    Joined: Jan 2005
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    ron17571 Junior Member

    Ive been doing much reading and have read about low rpm,(like a couple hundred)diesels wich direct drive to large props,mabe using a adjustable prop?seems like a way to get good fuel milage if used at displacement(lower) speeds.Thoughts?
     
  2. 40 years ago Holland had canal barges which at top speed fired once every 2 seconds as they moved. Very slow but did the job.
     
  3. B. Hamm
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    B. Hamm Junior Member

    Yep, works very well. Not many are available though, mostly due to the vibration they also produce and due to the extreme weight of these low speed diesels.

    Might do a web search for the Saab diesel, not made by the Saab car company btw, they are fishing boat engines produced in Norway. Uses a controlable pitch prop so the engine always runs the same direction and at the same fairly low speed regardless of direction of the boat or it's speed.

    Bill H.
     
  4. FAST FRED
    Joined: Oct 2002
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    Location: Conn in summers , Ortona FL in winter , with big d

    FAST FRED Senior Member

    IN the past low engine RPM was the way to longevity.

    Very low loads and simple enough that parts could be fixed or remade aboard.

    With almost 100 years of mfg behind them todays diesels are far more reliable , even at 2000 or 3000rpm for cruise than the old bangers were at 400rpm.

    Todays reduction trannys are very efficent and can match the engine RPM to shaft requirements with ease, and long life.

    A BIG slow turning prop is Still great for displacement speeds .

    FAST FRED
     
  5. Raggi_Thor
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    Raggi_Thor Nav.arch/Designer/Builder

    Search for SABB :)
     
  6. D'ARTOIS
    Joined: Nov 2004
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    D'ARTOIS Senior Member

    What about this?

    Brons - pre war - 50 Hp@200rpm
     

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  7. ZeeYachts
    Joined: Mar 2005
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    ZeeYachts Junior Member

    Check this site: http://www.farymann.de/
    I have used and repaired a number of their engines and have always been stunned by their thoughness and reliability.

    Zee
     
  8. asathor
    Joined: Oct 2004
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    asathor Senior Member

    Bukh made that type of engine in the "good old days" - If you find one you can undoubtedly still get it fixed.
     

  9. asathor
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    Location: Minnesota

    asathor Senior Member

    And if you want to go home just spin the flywheel the other way - the two strokes were nice that way.
     
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