Proposed changes to a bulkhead! Thoughts-Warning-Shouts Appreciated.

Discussion in 'Sailboats' started by wesley Sherman, Jun 18, 2021.

  1. wesley Sherman
    Joined: Jan 2020
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    wesley Sherman Junior Member

    Inkedalbergbulkhead_LI.jpg I am contemplating a bulkhead change idea!
    The white area is the area I would like to remove. The black line I am thinking is a glassed epoxied in support to reinforce the arch. Maybe it's not needed, there is going to be a bit of cabinetry around these areas.
    This is not my Alberg however I am too far from the boat to take a picture so borrowed someone else for this example. Hope they won't be mad!! but it is exactly the state of my interior at the moment.
    Is this dangerous? the amount of bulkhead on the port side is 11" wide by 3' Starboard side 6" by 3'
    I am not sensitive so please comment!
     
    Last edited: Jun 19, 2021
  2. JRD
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    JRD Senior Member

    Is that bulkhead supporting your mast? If so you probably need a rigorous design check to ensure the rigging loads don't exceed the material strength after you increase the unsupported span of the roof.
     
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  3. Blueknarr
    Joined: Aug 2017
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    Blueknarr Senior Member

    JRD is absolutely correct.
    That arch is structural. It will need some beefing up.
     
  4. wet feet
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    wet feet Senior Member

    I agree with the previous posts and I will add that any bulkhead cutout should have generously radiused corners and not sharp square ones.
     
  5. TANSL
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    TANSL Senior Member

    There seems to be a very strong beam that could be sufficient to support a mast. But it would be necessary to check it. On the other hand, if the bulkhead were completely eliminated, the frame on which it is now supported would always remain, or which is probably enough to support the existing loads in that area. In principle it seems that the planned opening could be viable. I use the word "seems" because, in my opinion, some calculation would have to be carried out to validate the solution adopted (but you should always round the corners of the cut. I agree with @wet feet).
     
  6. wesley Sherman
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    wesley Sherman Junior Member

    I should have explained better what bulkhead I am looking to change..

    This is not the bulkhead supporting the Mast Stepped Beam, rather it's the bulkhead on the cabin side The big beam or Mast Beam in the picture is on a bulkhead by the v berth forward of the bulkheads I am considering the cutaway.

    Inkedalbergbulkhead_LI.jpg
     
  7. fallguy
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    fallguy Senior Member

    What loads are supported by the bulkhead you wish to remove?

    Sort of an open ended impossible question.

    Just sayin.
     
  8. bajansailor
    Joined: Oct 2007
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    bajansailor Marine Surveyor

    And another question - why do you want to make this cut out?
    Is it to allow extra elbow room when making your way forward in the boat?
    I presume that the heads will be in the space between the two bulkheads - how will this be affected by the proposed cut-outs?
     
  9. wesley Sherman
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    wesley Sherman Junior Member

    I am laying out the interior for just me, no one else, not for resale or anything else. My plans were to place the head in the v berth ( yes I've thought this out and for me, it's the best solution) I know all the pros and cons of this choice. My thoughts for plans were to incorporate the galley amidships port and aft from the area between the bulkheads and into the galley area. The Settees are to be at the base of the companionway port and starboard. The reasons are I don't want the engine encased port and starboard by the galley and refer that was originally there. The cutouts are needed for the opening enough have counter cross the bulkhead a small amount. I've made a mock-up with heavy cardboard and have a layout that looks good and works well. Yes, venting is sorted out for the galley. Stove on the port side in the original head location on the port side, The refer on the starboard side on the cabin side of the starboard. The starboard side between the two bulkheads will a cabinet. I've thought of all the cons and pros of all the changes, I have weights sorted out to balance the boat.
    For the technical questions of what loads are sup0ported by the bulkheads, I have no knowledge of such things of that technology. Asking questions to get information of whether this is an easy or difficult thing to consider and if i need to sort out a NA then I will do that. Just basic feeling is that this cabin bulkhead is form supporting and that possibly removing this small amount might be possible. It seems the arch and step up is a pretty strong structure for the deck. Right now there is little to no support between the bulkheads that I want to cut out making me feel it is possible. But then this is why I come here not to express my knowledge but to get suggestions for possiblities. I am but a layman business owner that never graduated college guy that is enjoying my hobby from the aspect of a user, not a builder.
     
  10. fallguy
    Joined: Dec 2016
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    fallguy Senior Member

    You have to understand the loads.

    Take pictures of the real thing.

    Determine the loads that you understand. I don't mean anything complicated. If people walk, that is a walking load, if the mast is there, etc...

    In general terms, and that is all, you only cut what you must. For a countertop, you would never cut higher than the existing cutaways and then there is no reason to square cut the inside top, but you can leave a radius, etc.

    But, also, in general terms, there are times when no cutting is permissable. That is generally no cutting up higher...and your white lines are cutting higher than the existing...and that is a general no as well. Someone calculated the loads already and determined they needed a certain amount of BH above the opening..

    Too hard to say more..just don't plan on cutting higher for sure..
     
  11. wesley Sherman
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    wesley Sherman Junior Member

    The only weight in this area would be an emergency life raft suitcase which is 103 lbs, if the raft was not there the weight would be my weight of 250lbs. So lets say the life raft case is there and for some unknown reasons I stepped on the raft total weight would be 250+103.
    The original layout only had a 3/4 piece of teak crossing the bulkhead span and it was only a top jam for the door. so the span of 24" had no support.
    Would this make more sense Possibly?
    Inkedalbergbulkhead_LI.jpg
     
  12. TANSL
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    TANSL Senior Member

    Indeed, that is the question. I assume you are considering the loads that may be on the deck. One of them, perhaps the largest (that, at least, is what you say), is the weight of a person on the deck. But you have to take into account the accelerations to which the ship is subjected, which could double or triple that load. But sometimes it could be the case that there are 2 or more people on the roof of the cabin. It is something that only he who uses the boat can know. When I calculate a deck, in general though not always, I assign it a design pressure of no less than that due to 4 people/m2.
    But there is another small question to be taken into account. It is very possible, that is what is always done, that the transverse reinforcements of the deck have been calculated to support those loads on the deck, whatever they may be. In such a case, the bulkhead does not have to support those loads.
    But let's look at another aspect of the matter. If it is the bulkhead that must support these loads, we find a bulkhead that works in compression, with loads located in the same plane. Is the bulkhead material, the orientation of its fibers, adequate to withstand such compression loads? Because the normal thing is that the bulkhead is calculated to support loads perpendicular to its plane. A bulkhead is not usually designed to work in compression.
    In summary, it is very likely that the loads on the deck are not supported by the bulkhead so you could do what you want with it. But of course, the first thing to know is the function that the designer assigned to the damn bulkhead.
    So, indeed, "You have to understand the loads".
     
  13. wesley Sherman
    Joined: Jan 2020
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    wesley Sherman Junior Member

    TANSL
    Why this aggressive comment? I am guessing that everyone here is supposed to know more than I know? Guess this is your way of saying what are you doing here? I guess I came here to get an answer to why the damn bulkhead cant be slightly modified? or how to find out how to get the information to find out if I could modify the damn bulkhead.

    It's not your fault that I am an idiot and don't know anything, I am the non-graduated, unedumacted shrimp among all the whales.

    I stopped posting here for a while once before because your very critical and sarcastic, I guess I need a Senior Member Tag to get your respect. No disrespect to you but you could do well not comment on my posts. You're not beneficial to my sub-par intellect.
     
    Last edited: Jun 19, 2021
  14. Rumars
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    Rumars Senior Member

    There's no need for all the drama. Cut away as you like, glue a nice thick hardwood trim on all three sides of the cutout, be happy. If properly glued on the trim will act as a flange stiffening the bulkhead and restoring any lost strength.
     
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  15. fallguy
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    fallguy Senior Member

    what drama?

    Cuz tansl said damn?

    Or because guy wants to cut a hole in boat and someone said where and how much?

    silly
     
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