Adding Side Stringer on Shell Plating

Discussion in 'Metal Boat Building' started by petlily, Feb 5, 2007.

  1. petlily
    Joined: Jul 2006
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    petlily Junior Member

    In what occasion should a side stringer be added to the shell plating says, for a small steel tug abt 26m LOA x 8.0m B x 3.6m D? Does the inclusion of side stringer governed by the depth or due to the operational requirement alone? Suppose that we add the side stringer on the shell plating, is that mean that we can reduce the scantling of the side transverse and web frame as well (for a transverse framing system)?

    I have checked numerous class rules for small vessels regarding this side stringer issues but none of them clearly stated when should a vessel requires a side stringer. Can anyone shed light on this please?. Thank you.
  2. dirkpitt
    Joined: Sep 2006
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    dirkpitt Junior Member

    there is a rule of scantling with frames. if you don't add web longitudinal, frames' unsupported length will be increased. (between floor and deck beam). But if you add a web longitudinal (stringer) this unsupported length will be decreased and required section modulus of frames' also will be decreased. This is it. But other longitudinals (if it isn't web) doesn't effect unsupported length. Because web beam, floors supports web frames; bulkheads, web frames supports web girders. other longitudinals' required section modulus can be calculated in some rule books R.I.N.A. etc. it is old post i know but i would like to answer it...
  3. TANSL
    Joined: Sep 2011
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    TANSL Senior Member

    Simply check the scantlings you get using, not using, stringers. Note that a primary element (eg a frame) must have some scantlings that depend on several things, mainly its length. And a secopndary element, such as longitudinal stringers, can never be used to reduce the light of the primary element. That is, for many stringers you add, the scantlings of the frame will not change.
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