Minimum practical thickness of aluminium?

Discussion in 'Metal Boat Building' started by Raggi_Thor, Dec 14, 2005.

  1. Raggi_Thor
    Joined: Jan 2004
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    Raggi_Thor Nav.arch/Designer/Builder

    What is the minimum practical thickness of aluminium?
    It seems like even the smallest boats are built of minimum 2mm alu?
    I ask because "aitchem" asked for an aluminium version of the Backman 18.

    I have always thought that for small light boats it's the local stiffness that is the dimensioning factor while for large (long) heavy boats you also have to look at the global stiffness (the hull as a beam supported at each end).
    If 6mm plywood at 3kg/m2 is a practical minimum, I can't see how small aluminium boats can be as light as a plywood boat.

    Any comments from the metal boat builders?
     
    Raggi_Thor, Dec 14, 2005
    #1
  2. Raggi_Thor
    Joined: Jan 2004
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    Raggi_Thor Nav.arch/Designer/Builder

    Did I post to the wrong forum?
    Is 3mm the minimum practical thickness to weld?
     
    Raggi_Thor, Dec 15, 2005
    #2
  3. alyne
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    alyne Junior Member

    Not sure about sheet alluminium, but I have just had a frame tig welded together using 16guage (approx 1.6mm) thick aluminium tubing. Worked a treat!
     
    alyne, Dec 15, 2005
    #3
  4. Thunderhead19
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    Thunderhead19 Senior Member

    Being able to weld it is the real issue on small boats. Riveted hulls can be as thin as 1mm. 3mm makes a good easily, inexpensively, weldable, durable hull, 4mm and you can go ramming other boats.. well not quite..
     
    Thunderhead19, Dec 16, 2005
    #4
  5. Raggi_Thor
    Joined: Jan 2004
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    Raggi_Thor Nav.arch/Designer/Builder

    Thanks to both of you, maybe riveting or gluing is the way to go in very small boats?
     
    Raggi_Thor, Dec 16, 2005
    #5

  7. gonzo
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    gonzo Senior Member

    Palmer Johnson used to build 12M boats in glued, lapped aluminum.
     
    gonzo, Dec 17, 2005
    #6
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