Would you mount this panel on this bulkhead?

Discussion in 'Boat Design' started by MJT, Jan 6, 2021.

  1. MJT
    Joined: Jul 2012
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    MJT Junior Member

    Hello, and thank you in advance. This site is an invaluable resource.

    I'm in the late stages of a thorough restoration of a 1970 Cheoy Lee Offshore 40, and I'm debating the location of the electrical panel with my systems guy.

    From the standpoint of electronics only, the location indicated in the photograph makes the most sense. Closest to the batteries, and the back easily accessible from the other side of the bulkhead. Also, not on a swinging door, so no flexing of wires.

    This bulkhead is on the starboard side, just about just aft of the mast. This, and the bulkhead opposite would be considered the main bulkheads. There is a set just forward of the mast which are about the same size, but just a bit smaller.

    [​IMG]

    The reason this is a debate is that I'm concerned about the cutout for the panel having an adverse affect on the strength of this bulkhead. The bulkhead is 3/4" (18 mm) Okume marine ply and glassed in properly along ceiling, cabin-top sides, under-deck, and hull.

    The mast is deck stepped on this massive mast step, which distributes the load to two steel compression posts.

    [​IMG]

    Here you can see the bottom of the posts, and the posts rest on a hefty laminated stack of white oak that, in turn, sits on the keel.

    [​IMG]

    Appreciate any insight!
     
  2. rangebowdrie
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    rangebowdrie Senior Member

    What's on the other side of the proposed cut-out space,, could a stiffener(s) be added?
    In any case I would have a nice frame around the cutout and back-mount the panel, perhaps even having a hinged or sliding plexi panel to protect the switches/breakers, from inadvertently being operated/brushed against.
     
  3. MJT
    Joined: Jul 2012
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    MJT Junior Member

    The other side is the inside of a hanging locker. I would "box off" the wiring to isolate it and be sure to not store anything wet in the locker. This is an old picture, but it shows the two hanging lockers, and that there is a bulkhead that separates them. The bulkhead on the right, with white primer, is the one I'm considering for the panel.

    [​IMG]
     
  4. gonzo
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    gonzo Senior Member

    Electrical panels should be recessed and preferably have a lid. Otherwise, people will lean or push on them and break components. If you have no problem making a box into the locker, it should be deep enough to house the whole panel and allow for a door.
     
  5. MJT
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    MJT Junior Member

    Thank you. This is good advice. I had planned on a box and plexiglass lid, but such that the front of the panel is basically flush with the bulkhead. Additional recessing would offer additional protection, and perhaps would look better too.
     
  6. fastwave
    Joined: Jan 2007
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    fastwave Senior Member

    Without calculations you can never be sure but an old rule of thumb I was told from some old school guys is too add at least as much material you removed to the frame around the hole.
    Mind you this was probably aimed for small round holes.
    Try to avoid being to close to that inboard edge of the bulkhead.


     
  7. MJT
    Joined: Jul 2012
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    MJT Junior Member

    Thanks for the conversation. The hole in the photo below is still rough, but I have since used the routing template to clean it up.

    That's not final installation, I need the screws/bolts, I need to prime and paint the perimeter of the cutout. I need to build the frame and get hinges and plexiglass.

    The back of the panel is in a hanging locker, and I'll need to "box in" the wiring. The construction of this boxing in will serve as additional reinforcement of the bulkhead.


    [​IMG]

    [​IMG]

    [​IMG]
     
  8. JSL
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    JSL Senior Member

    This may seem totally 'out there' but consider lightning protection. Appears the panel is adjacent to a chain-plate & there is no ground strip (yet): a 'strike' could arc to your panel.
     
  9. MJT
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    MJT Junior Member

    Nothing "out there" about lighting protection, especially considering that I have wooden masts, and those chainplates will be the best electrical path to ground. Each chain plate will be grounded.
     
  10. philSweet
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    philSweet Senior Member

    Looks good so far.

    Does she have fore and aft lowers? I'm guessing the main bulkhead supports the cap and mid shrouds, and the gusset supports ann aft lower, with the forward lower tied in front of the bulkhead. I'd add a cleat of plywood under the shelf and above the panel full width of the bulkhead and call it good. Run the plywood with the face grain transversely.

    You'll want plenty of room in the panel's back box. Before long, all kinds of stuff will get dead-bugged into that box. I'd build a box about five inches deep that just goes right down to the floor. Give yourself about four inches of room on the outboard side for cabling. Capture the bottom on the floor and bolt the top to the added cleat and you can get at everything in ten seconds. Try not to put the AC in that closet - it's the perfect place - but not with the panel there. If you do, I'd build another divider and maybe put 1/2 foam insulation on it.
     
  11. gonzo
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    gonzo Senior Member

    The panel is where people will be leaning against. It would be a lot less work to simply cut a rectangular hole and back mount the panel. At least you will get the thickness of the plywood for protection.
     
  12. philSweet
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    philSweet Senior Member

    ... Or at least add a teak grab handle next to it to prevent slap-happy people bapping the shower sump as they walk past.
     
  13. Squidly-Diddly
    Joined: Sep 2007
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    Squidly-Diddly Senior Member

    at airports, hospitals, etc they like to mount electrical panels on 3/4" fireproof plywood that itself is mounted over sheetrock and screwed to metal studs or concrete wall. The purpose of the wood is to give them something fairly sturdy but also easy enough to attach stuff to, or if needed bore through...panels and various cable holding stuff.

    The fireproof plywood doesn't cost barely any more than regular and I hear its also water damage resistant.
     

  14. MJT
    Joined: Jul 2012
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    MJT Junior Member

    Yes, fore and aft lowers. The compartment the back of the panel sees has the upper chainplate knee.

    I plan on making the back-box very spacious, and thanks for the reinforcement, and tips!

    I'll continue to update this thread as I make progress with my electrical system.
     
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