What is the "bulkhead deck"?

Discussion in 'Class Societies' started by ldigas, Dec 27, 2011.

  1. Alik
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    Alik Senior Member

    If You post Your calcs, some of us might have a look...
     
  2. Perm Stress
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    Perm Stress Senior Member

    If your prototype was not classed, the bulkheads well could have been made by "common sense" of builder and/or designer.
    There are quite a few boats, made to "common sense" of owner/builder/whoever with weird structural arrangements.

    If your prototype was classed to rules of other society, or for inland instead of for offshore use ....

    If those bulkheads were not designed as watertight, (i.e. compartments are there only for practical use of boat, not to enable her to survive serious hole in bottom), quite different set of loads and scantlings are applied.
     
  3. MikeJohns
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    MikeJohns Senior Member

    How many watertight bulkheads do you expect? Is this supposed to be unsinkable offshore?

    I'd expect a crash bulkhead fwd, and a fore and aft engine compartment bulkhead up to a steel cabin sole and no others actually required for watertight subdivision.

    The rest are then stiffening bulkheads for the hull and not for watertight integrity.
     
  4. ldigas
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    ldigas Senior Member

    Yes, that has been my reasoning too (crash blk. + two watertight sealing off the engine room; the others being there for hull stiffening and space separation). However, from what I read in the rules, non-watertight bulkheads are dimensioned according to the same rule

    5.3. Non-watertight bulkheads

    Components of non-watertight transverse or longitudinal bulkheads, wing bulkheads or such which serve to stiffen the hull are to be dimensioned in accordance with the same formulae.
     
  5. Petros
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    Petros Senior Member

    any horizontal floor diaphragm structurally attached to the bulkhead will be a bracing element, be it the uppermost deck or not. this will reduce the stress on the bulk head so less structure is required. So the free height of the bulkhead between the structural deck levels will determine the stress on the bulkhead elements.

    The GL rules have different levels of strength required for different classes and different types of ships or yachts, so the strength depends on the intended use.
     
  6. Alik
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    Alik Senior Member

    It might be treated as accommodation bulkhead attached to side frames, so there is no need to comply with requirements.
     
  7. ldigas
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    ldigas Senior Member

    So, if I'm to understand correctly ... if the bulkhead is attached to the frame/deck beams etc. etc., i.e. it is not a bulkhead, but more of an accomodation bulkhead then it is not dimensioned according to the same rules, but more according to the common sense of the nav. arch.?

    Although some stiffeners are still good to have, even on those.

    Am I somewhere close with this?
     

  8. Alik
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    Alik Senior Member

    Accommodation bulkhead does not need to comply if there is enough structural elements. We use accommodation bulkheads in plywood on aluminium craft... Stiffeners -those might be just used to provide stiffness of bulkhead.
     
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