How to make lids for hopper barges?

[Rvjimd]

Question for everybody...

I have wanted to make lids (sliding covers/hatches) for my hopper barges. I am wondering about the easier method.

Make a male plug, learn about and build a vacuum table with heat source and pull them out of plastic. My buddy has a setup like this, but thought a single piece hatch might be too big to do successfully. The open area is about 18" x 4".





Here is a picture of the ends of a few covers. I don't expect to do a huge amount of detail, just the basic shape with a few of the rib shapes to look similar.



Method to, similar, do this in the oven without the vacuum source.

Three, make them from a single layer of glass cloth and resin/hardener. Would maybe try a vacuum approach again.

I have never done anything like this before, not intimidated by the thought, just not experienced to know the best approach?

I would need to make about 8 or 10 of them. I want to do at least 6 and make them one piece to keep rain out, so I could leave the barges out in the rain. I would also cut a few of them up so they would look like a sliding lid, left part way open.
They would just slip over the side walls that come up from the inner side walls.

I'm sure there are some opinions on each method, as well as others not listed here.

Thanks

Jim