Inboard Air cooled Surface Drive

Discussion in 'Surface Drives' started by flathead65, Jul 11, 2022.

  1. flathead65
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    flathead65 Jeff Thompson

  2. bajansailor
    Joined: Oct 2007
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    bajansailor Marine Surveyor

    Impressive videos!
    What is the rated power output of the engine?
    Do you steer the whole engine, in similar fashion to the Thai longtail boats?
     
  3. flathead65
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    flathead65 Jeff Thompson

    The engine is a 22 hp V-twin. Yes you steer the whole engine.
     
  4. DogCavalry
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    DogCavalry Soy Soylent Green: I can't believe it's not people

    Fantastic videos! How is she getting on the plane? How big a prop? How fast, how heavy?
     
  5. baeckmo
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    baeckmo Hydrodynamics

    Nice setup, good job!
     
  6. flathead65
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    flathead65 Jeff Thompson

    The boat gets right up on step. The prop is a 9"x5. I would guess mid 20's mph ( I haven't done a gps). The boat is 16ft. x 48" all welded .125" so, quite a bit heavier than most your typical jon boats. The engine weighs 100 lbs all stock except for the exhaust.
    22hp. gets her moving right along.
     

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  7. flathead65
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    flathead65 Jeff Thompson

    Thanks baeckmo.
     
  8. DogCavalry
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    DogCavalry Soy Soylent Green: I can't believe it's not people

  9. flathead65
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    flathead65 Jeff Thompson

    Thanks again.
     
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  10. philSweet
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    philSweet Senior Member

    How did you get your hands on a Briggs Vanguard? I've got two broken ones I'm having to rebuild because new ones are unobtainable. No one can even tell me when they can get me one - just "not in the next six months." I just ordered about $400 worth of parts today to rebuild one of them.:( We get about 6000 hours out of them at 2850 rpm. But I can't stop the guys from winding them up to 3000rpm.
     
  11. flathead65
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    flathead65 Jeff Thompson

    It's a Harbor Freight Predator. Interesting about the Briggs though. I wonder what all the mudmotor manufacturers are doing for engines?
     
  12. flathead65
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    flathead65 Jeff Thompson

    The shallow water capabilities of the drive.
     
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  13. flathead65
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    flathead65 Jeff Thompson



    In "The Dewdney" video you can see the extension spring absorbing bottom strikes. It also suspends the engine up against the manual trim adjuster. That coupled with trim tabs on the protective skeg keep the prop in the water and provide a very neutral tiller. The gimbal gives ample steering and there is plenty of trim adjustment. The shaft assembly comes about a foot out of the water. I wanted to build the direct coupled shaft /engine gimbaled arrangement of the Thai longtail with the thru transom design of the Burmese boats for low shaft angle. The shaft is 32" more like the American outboard surface drives. So far it is working for my purposes.
     
  14. flathead65
    Joined: Apr 2014
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    flathead65 Jeff Thompson


  15. flathead65
    Joined: Apr 2014
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    Location: Mission B.C. Canada

    flathead65 Jeff Thompson

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