a floatable foamie?

Why not? It could be for ponds and small lakes, or canals (hey Brits! a shortie foam weekender narrowboat?)
If a foamie was epoxy/fiberglass on the bottom and about 12" up the sides, it would float, I bet. You could also inject some floatation foam in strategic places to make it unsinkable (if it already wasn't). I would rest it on the trailer, and tie it down with cargo straps.
If a foamie was epoxy/fiberglass on the bottom and about 12" up the sides, it would float, I bet. You could also inject some floatation foam in strategic places to make it unsinkable (if it already wasn't). I would rest it on the trailer, and tie it down with cargo straps.