Arneson drive and engine loading

Discussion in 'Surface Drives' started by jtheriot, May 25, 2018.

  1. jtheriot
    Joined: May 2012
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    Location: New Orleans

    jtheriot Junior Member

    Im am looking into the possibility of using a Asd10 with a qsc500 cummins for commercial application. The main reason for consideration is due to the need for very shallow draft in certain situations. A added possible bonus would be a significant improvement at fast cruise vs traditional inboard. A typical day consists of up to 4hrs on plane cruise (should be around 28kts w strait shaft) and 10 hrs of slow speed maneuvering (4-7 kt). My understanding is that due to only half the propeller being submerged when planed out that (in layman's terms) you would use twice the size propeller. My main concern is that the engine would be overloaded for the majority of the workday due to the drive acting as subsurface. Would this not be a concern because the engine is not typically under heavy loading until the point that the stearn squats and actually breaks plane?
     
  2. Rik
    Joined: Dec 2007
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    Location: California

    Rik Senior Member

    The propellers are not "twice" the diameter and the engines will not be unduly loaded anymore than a normal application. You will not have any issues with this to be honest.

    Call me or email me.

    415-485-0788

    Rik
     
  3. gonzo
    Joined: Aug 2002
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    gonzo Senior Member

    One solution that has been used successfully to unload the propeller when accelerating from a stop, is to put the exhaust right over the drive. It ventilates the upper blades, and lets the engine rev up. It is particularly effective with turbochargers, because they will spool up.
     
  4. jtheriot
    Joined: May 2012
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    Location: New Orleans

    jtheriot Junior Member

    Thanks for the replys. The boat is a dave sintes design Louisiana laffite style skiff. This is a very uncommon style of propulsion and I doubt it has been done before on this type of boat. Outboards have been the solution for shallow draft but I would like to stick with diesel power. Im right at 10k hrs right now on a 5 yr old 430c cummins. Between the amount of hrs and the ability to run hydros and pto pressure washer off the engine I dont think outboards are my anwser. Im open to trying something different that I think solves my issues plus I can retain the classic lines of the hull without having to alter the fantail and have two outboards. Thanks for the offer Rik , once I have more solid idea of any obstacles I will contact you.
     
  5. jtheriot
    Joined: May 2012
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    Location: New Orleans

    jtheriot Junior Member

  6. jtheriot
    Joined: May 2012
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    Location: New Orleans

    jtheriot Junior Member

    I understand the use of exhaust to induce ventilation for a easy option. Although not the cheapest, whould the use of a 2 speed zf trans be a sure option.
     
  7. Rik
    Joined: Dec 2007
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    Location: California

    Rik Senior Member

    You will not need a 2 speed transmission. To be honest, they are twice the cost, twice the weight and twice the length. This changes a lot of things as far as LCG and such.

    The boat bottom looks like a shallow deadrise, so it should do well in shallow water and should be a fast boat.
     
  8. Mr Efficiency
    Joined: Oct 2010
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    Location: Australia

    Mr Efficiency Senior Member

    Your estimate of 28 knots cruise seems rather high to me, but you are the man on the spot. You really don't think of surface drives as being suited to the lower speed ranges, they came into use for high speed, racing-type vessels, and typically they suit boats that are not overly stiff longitudinally, underway, and can use tabs to bring the bows down. If the bows are digging in with a surface drive, and not under the impress of tabs, there isn't a lot you can do to lift them, to where you might like it better.
     
  9. FredericPT
    Joined: Jan 2019
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    Location: Guayaquil Ecuador

    FredericPT New Member

    I been using a asd 8 for more than 25 years, installed in a work boat in Guayas river that is very dirty,
    Before I use to break a stern drive twice a year.
    With the Arneson the only problem I had was with the protection rubber, an it took some time to find the right prop.
    Now in my 24 ft with a Cuumins Diamond 370 with a 1.56 gear I'm doing 50 ml. max and at 2900 rpm and cruise at 38 ml at 2000 rpm
    I'm really happy with the combination especially traveling more than 1000 hours a year.
    I have a lot of experience with surface propulsion systems.
    If you think I can help please write at
    fpetrillit57@gmail.com
     
  10. jtheriot
    Joined: May 2012
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    Location: New Orleans

    jtheriot Junior Member

    Thanks for the insight. I am still exploring the option.
     

  11. Barry
    Joined: Mar 2002
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    Barry Senior Member

    Why not consider a jet?
     
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