Design aluminium shallow water

Discussion in 'Jet Drives' started by Gian Milan, Jun 20, 2011.

  1. hoytedow
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    hoytedow Fly on the Wall - Miss ddt yet?

    Nau mai, mohawk!
     
  2. Gian Milan

    Gian Milan Previous Member

    Hi mohawk!
    TU for your interesting advise.
    I posted a link to youtube about your little jetboat! I'm happy to know you!

    Now, with necessed time, i the links u make me have.

    T.U.
    Gian
     
  3. mohawk
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    mohawk Junior Member

  4. Gian Milan

    Gian Milan Previous Member

    Shallow water jetdrive, diesel

    Hi
    Please, post all mistakes you can see.
    In the boat (18*6) I want install a castoldi drive 238 and a Mercedes diesel 2900 rpm about 50 hp.

    Grazie a tutti!
     

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  5. hoytedow
    Joined: Sep 2009
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    hoytedow Fly on the Wall - Miss ddt yet?

    I like it.
     
  6. mohawk
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    mohawk Junior Member

  7. Gian Milan

    Gian Milan Previous Member

    TU mohawk.
    But when the boat go on, tunnel is not water full?
    If the tunnel will be filled with air, it might be ok for surface propeller?
     
  8. mohawk
    Joined: Jun 2011
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    mohawk Junior Member

    As the boat moves forward the tunnel will fill with air . Its very important to keep the flow of water to the unit clean. For low speed shallow water boating a 5-10 deg v bottom is good, no tunnel.
     
  9. hoytedow
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    hoytedow Fly on the Wall - Miss ddt yet?

    If cavitation plate over propellor is level with or slightly below lowest point on transom you should have no problem.

    Never mind.
     
  10. anthony goodson
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    anthony goodson Senior Member

    hoytedow I think you may be at cross purposes here ,the man wants to install a 238 castoldi ,mohawk understands this ,and is correct.
     
  11. hoytedow
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    hoytedow Fly on the Wall - Miss ddt yet?

    Oops. Sorry.
     
  12. thudpucker
    Joined: Jul 2007
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    thudpucker Senior Member

    Somebody yell out loud to straighten me out here.

    In AK we had a heckuva lot of Jet boats for Rivers, slow and fast, and lakes.
    None that I ever saw or owned had a Tunnel.

    We like the stern to be a hi-surface design so the Jet inlet is the only thing even slightly below the surface. The wider the flat bottom, with little crown, the better the boat goes over rocks etc.

    So why the Tunnel on the Europeon design. Are we missing something?
     
  13. hoytedow
    Joined: Sep 2009
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    hoytedow Fly on the Wall - Miss ddt yet?

    I may be wrong again, but I think he is going for the water ski effect of less wetted surface to lessen friction, as I did in my latest design.
    The boat is designed to perfectly fit the bed of a 2007 Toyota Tacoma while it pulls a teardrop trailer. The bow is rounded so it never touches the trailer while driving.
    It is designed for two passengers with low horsepower outboard motor on calm water like slow moving lowlands rivers, estuaries or lakes.

    http://www.boatdesign.net/gallery/showphoto.php/photo/16306/ppuser/32990
     
  14. thudpucker
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    thudpucker Senior Member

    Thats a good lookin thing you drew up there. I got kinda lost looking at it though. I thought it was an optical illusion at first. ;)
    That rounded front is better than the squared off front. It should be a little higher if your gonna run rivers with it because you'll be dipping into wave trough's near Rocks and dont really want a Submarine in them there parts.
    Also when you run up on a log etc the hi bow makes it a little easier to keep going.
    Pulling up on the beach it's good too because some beaches are two feet hi or so. :)

    I still think a good River craft needs all the wetted surface it can have where the weight is centerd over.
     

  15. Gian Milan

    Gian Milan Previous Member

    I thank you all for your valuable answers and I'm sorry for my English, probably difficult to understand.Why I give you some data about the boat and what I want obtain. Dimensions in meters:
    Length 5.5 width 1.7 height 0.8.
    TYPE OF RIVER SAILING:
    The boat is designed to navigate rivers slow, some with extremely low water. Navigation not fast, average consumer must be very low . It's a boat made to sail with the whole family on a Sunday, making up to 30 miles. The engine should be a 238 Castoldi, but if an outboard propeller surface he could fish in the tunnel, would be appreciated.
    In the U.S.A. SJX has a tunnulle and a mercury jet.
    Someone built shallow water boat with tunnel and outboard engine; I don't understand the propeller:
    http://www.dreamboats.net/
    http://www.flatscat.com/

    Ciao a tutti Voi!
     
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