The single part epoxy and the two part epoxy are both compatible with wood.
I have used the single part (clear) from Home Depot quite a bit and it penetrated well and forms a good surface and good finish.
The acrylic epoxy just need a clean surface to work well. I have used it particularly to seal the sides of plywood to keep it sealed and tight.
For the floor on my 16' Scamp
I used two part laminating epoxy and glass fiber fabric on both sides and the edges before I installed it to make sure it was sealed ans as waterproof as I could make it. I the bonded the fiber glassed floor to the shell with strips of fiberglass fabric and the same epoxy.
The single part garage floor epoxy (clear also seems to give a pretty good finish if built up properly. It seems to soak in well enough to seal especially when two or more coats are used.
I have not used this over fiberglass or painted wood, but epoxy sticks to pretty much everything that is clean and free of oil and grease. If you rough it up it will probably work OK.
If you use the stuff they make gloss and satin finish. I had some mixed to touch up a Kubota deck and forgot to make certain that they did not add the flattener so I have a satin mower deck. It has held up pretty good though!