As I said earlier, plywood sheets are only 2440mm or 8' long. But what if you need a longer panel, for example for the side panels?
My dive boat and even the simple canoe I built, needed side panels much longer than 2440mm or 8'.
Making a Butt Block
For this I had to merge 2 pieces together using a Butt Block!
A Butt Block keeps the two side panels together
Just stick the two parts together bluntly and stick a piece of plywood or a stripe of fiberglass on top of the seam. Of course, glue everything together with epoxy.
Notice the 5 cm or 2" gap between the butt block and the edges of the panel! This is for the seam of fiber mat and epoxy.
Let the epoxy dry and harden over night or for at least 12 hrs before you may try to bend the whole panel.
Make sure that the extra piece of plywood is on the inside of the boat.