Ah... square tubing... that would be better. I recommend using 1 inch inner diameter standard modulus square tubes:
1. https://www.rockwestcomposites.com/25488-long cut to size for your 78" sections.
2. https://www.rockwestcomposites.com/25488 for the shorter 55" pieces.
and connect them together with something like this: https://www.mcmaster.com/47045T82/ I have not been able to find any carbon fiber square tube connectors out there, but I think any tough plastic or aluminum piece will do. Use a rubber mallet, and (maybe a few brushes with some sandpaper) to insert the connector into the tube. You can bond them if you want with a touch of cyanoacrylate epoxy (super glue), but I don't know if that is necessary.
As far as attaching the wood to your carbon fiber frame, I would say you will need a fastening system that is more durable and lasting for the wear and tear of life at sea. I recommend that you fasten your wood panels to the carbon fiber frame using regular metal nuts and bolts, with a flat head that is aesthetically acceptable to you. Drill pilot holes through your square carbon fiber tubes with a regular metal drill bit and a strong drill (if your tube is securely immobile, this is pretty easy).
Lastly, you will need to secure the bed frame to your boat. I would think you would want to bolt it to the floor or wall using the same method.