: Can i use plywood for my bulkheads if i cover them with fiberglass

Yes you can use plywood and no, you don't have to cover them with fiberglass, but coat them with epoxy, both sides and the edges prior to bonding in place. Of course you can cover them with glass if you feel the need, but covering only one side is not adding much strength at all. If you are trying to beef up the strength, you need to do both sides.

Position them and hold them in place with a few dabs (or maybe blobs) of hot melt glue, then bond them in place with a fillet of epoxy/woodflour/cabosil mixture. I find it most convenient to mix to consistancy of peanut butter, place in a plastic baggie and force to a corner of the baggie, cut the corner off and squeeze the mixture out like using a pastry bag. Finish off the fillet by smoothing with a rounded end of a scrap strip, or a tongue depressor.

Make sure you fillet both the front and back of the bulkheads.

Many builders prefer to fiberglass the bulkheads in place for strength. Believe me, the epoxy fillet is going to bond those bulkhead in place and they are never going to go anywhere. (unless your fillet is very very skimpy) A 1/2" radius, or 1/4" up the bulkhead and 1/4" to the kayak will be more than sufficient.

Tom