river boat progress

Discussion in 'Boat Design' started by rfleet1066, Jan 19, 2013.

  1. Angélique
    Joined: Feb 2009
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    Location: Belgium ⇄ The Netherlands

    Angélique aka Angel (only by name)

    Re post #75

    anti ventilation plate on truss long tail.jpg
    — angle your screen, or a print, or your imagination, till the waterline becomes horizontal —

    For a better water flow to the prop and less resistance, maybe the underwater end of the long-tail is only a tube that houses the prop shaft and the down end bearing ?
     
    Last edited: May 26, 2019
  2. Angélique
    Joined: Feb 2009
    Posts: 2,916
    Likes: 295, Points: 83, Legacy Rep: 1632
    Location: Belgium ⇄ The Netherlands

    Angélique aka Angel (only by name)

    Resistance in the water flow towards the prop causes the need for the prop to suck harder to get enough water, and so obstructions in the water flow in front of the prop can cause cavitation. Remedy for this is to allow for a free as possible water flow towards the prop. Hence my suggestion in the last line of post #76 for a tube underwater end on the truss long-tail, and so have no obstructing truss construction in the water in front of the prop.
     
    Last edited: May 22, 2019
  3. rfleet1066
    Joined: Feb 2012
    Posts: 136
    Likes: 10, Points: 18, Legacy Rep: 46
    Location: New Kent, VA USA

    rfleet1066 rfleet1066

    I have fabricated and installed the anti-vent plate with good results. I get a 35% speed increase with zero ventilation at the same power setting as before. Also, vibration caused by ventilation is now non-existent. My engine is loaded fully at 2000 rpm with 2400 rpm available, so I need to either tweak the engine for more HP or tweak the prop. Also, I need to install fairings on the boom to smooth the delivery of water to the prop. But I am absolutely giddy with the improvement and cannot thank you enough for the suggestion. IMG_2427.JPG
     
    Dejay likes this.
  4. rfleet1066
    Joined: Feb 2012
    Posts: 136
    Likes: 10, Points: 18, Legacy Rep: 46
    Location: New Kent, VA USA

    rfleet1066 rfleet1066

    Be advised, I didn't know the first thing about a boat, let alone a ship, when I started this project. Heavily armed with ignorance, I proceeded. This is my first try at boat building. This forum has been a valuable resource. Hey Forum! I'm one of your success stories!
    I'm not a taker. How can I repay this? Be reasonable.
     
    Last edited: Jun 14, 2019 at 6:08 PM
  5. rwatson
    Joined: Aug 2007
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    Location: Tasmania,Australia

    rwatson Senior Member

    Links to a few YouTube Videos of the whole system in operation and the boat would be a good idea. :)
     

  6. BlueBell
    Joined: May 2017
    Posts: 642
    Likes: 61, Points: 28
    Location: Victoria BC Canada

    BlueBell Ahhhhh...

    As above but keep building!
     
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