Lapstrake/clinker aluminum boat plan

Discussion in 'Metal Boat Building' started by Eciton, Feb 3, 2021.

  1. Eciton
    Joined: May 2017
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    Eciton Junior Member

    Just curious about the feasibility of using sheet aluminum rivetted together in lieu of plywood or wooden planks for a lapstrake boat.

    It's not that weird, I would think someone at sometime has done it. I know I have banged up and rebent my share of Grumman canoes that had decades on me over the years so the riveting method works.

    Some wooden boat designs I just love, but i want them in aluminum. :)

    if possible what would be the equiv strength of 3/8'' marine ply?
     
  2. Mr Efficiency
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    Mr Efficiency Senior Member

    To get the same visual effect, your "planks" would need to approximate in thickness, that used in clinker wooden boats. That would mean your planks had better be hollow extrusions ( they certainly are available), otherwise the weight will kill it, alloy is 3-4 times the SG of wood. The lapping of the extrusions might also create a home for poultice corrosion, especially if unpainted.
     
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  3. Eciton
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    Eciton Junior Member

    you think? starcraft and others made stamped aluminum hulls that had very small reveals and still gave it that lapstrake look.

    i contend the aluminum plate could be much thinner and even if painted would still give the impression of a lapstrake.
     
  4. Mr Efficiency
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    Mr Efficiency Senior Member

    I know what you are saying, but to get the shadow effect, you will need fairly thick material.
     
  5. Rumars
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    Rumars Senior Member

    It's possible, just not a very bright idea. Strenght will be the last of your problems, stiffness, weight and waterproofing are more important.
     
  6. bajansailor
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    bajansailor Marine Surveyor

    Eciton, there is a huge difference between stamping out an aluminium hull in one piece, with chines 'built in', and riveting lots of pieces of aluminium sheet together.
    And unless all of the chines are absolutely perfectly smooth and fair it will look like a real bodge.

    As Rumars notes above, 'Strength will be the last of your problems, stiffness, weight and waterproofing are more important.'
    Definitely!
    Even 1.5 mm thick ally plate is strong stuff.
    And it could be riveted.
    But you won't get the stiffness of 'thick' chines by simply lapping strips of 1.5 mm plates and riveting them.
    Re waterproofing, would you use a sealant under the rivets?
     
  7. Mr Efficiency
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    Mr Efficiency Senior Member

    It is a crazy idea if only because you have a hundreds of metres of seams to deal with, unlike wood alloy won't "swell" to take up any slack. And rivets all over the place will not be a good imitation of wood clinker. And you better not use any sealing method that allows water to sit between the laps, or you will be able to hear poultice corrosion chewing into it on a quiet night. GRP has been used to make some very attractive clinker boats, but not as a one-off proposition
     
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  8. gonzo
    Joined: Aug 2002
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    gonzo Senior Member

    Stamped fake lapstrake is not the same as riveting aluminum planks. Which one do you want to make?
     
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