TX Flats Boat Rebuild - Stringers & Sole

Discussion in 'Boat Design' started by Corey Fields, Mar 19, 2019.

  1. Corey Fields
    Joined: Mar 2019
    Posts: 1
    Likes: 0, Points: 1
    Location: Houston

    Corey Fields New Member

    Hi guys,

    I'm re-building a 16' TX flats boat. I pulled some rotten deck up tonight and saw it was sitting on 2x4 laid athwartship and stood on end on 1' centers. The 2x4 sit directly on 5 glass stringers on 10" centers and span 69" and are tabbed into the hull sides. Are the athwarship members also called stringers?

    That spacing seems like a lot doesn't it? The boat, which is of unknown make and era, currently has 1/2" ply with what appears to be only one layer of mat. I was planning on using 1/2" ply with one layer of 1708, and maybe vail on top of that. Think I could to 2' centers?

    Or is there a better way altogether?

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  2. Blueknarr
    Joined: Aug 2017
    Posts: 1,383
    Likes: 361, Points: 83
    Location: Colorado

    Blueknarr Senior Member


    No on the 2 foot centers under 1/2 inch ply. Those wide centers would require plywood 1 1/2 inches thick

    1708 is a little overkill bot will wear longer. So an OK idea.

    I found that if one plywood is rotting then all the plywood is rotting. Check the stringers and beems for rot thourally. Also check your transom's plywood core.
  3. messabout
    Joined: Jan 2006
    Posts: 3,273
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    Location: Lakeland Fl USA

    messabout Senior Member

    Corey; if the boat has 2 x 4 s on ten inch centers it is unnecessarily heavy. You can replace the crossmembers (beams) with 1 x 4 without sacrificing much stiffness. Save some weight and a litlle bit of money that way. A beam has what is called a moment of inertia which is the measure of stiffness of the element being examined (beam) . It is calculated by multiplying the width times the depth raised to the third power, that quantity all divided by the number 12. (W x D^3)/12

    With that simple equation you can see that the width of the beam is far less important than the depth. A ratio of 1.5 to 42.8........ The 2 x 4s were clearly overkill perhaps done by a builder who was using excesses in order to make the boat earthquake proof. Leave the original spacing as it is. That too may be overkill but I would not want to make the spacing much wider. The spacing choice is closely related to the thickness of the bottom and somewhat concerned with the thickness of the flooring and how well the flooring is attached to the beams. .....Think of the collective structure as a long, wide, I beam.
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