Barge building regulations- hull materials

I would like to build a flexible barge with a hull made of plastic and other unconventional materials.

:?: Does the hull of a barge need to be a certain material in order to be approved by the US Coast Guard?

:?: Do they look for certain things in a newly designed vessel?

:?: Does a barge need to be approved or licensed at all or is exempt when its un-powered?

If you don't know I would appreciate it if you could connect me with someone who does know.

Thanks!