The outer bumper makes them look stronger than they really are. They look like a big steel box but inside there's just a minimal amount of ribbing that is only supposed to take forces straight on. They're designed so that if they get loose in a flood and hit something, they'll crumple and sink.

The outer bumper makes them look stronger than they really are. They're designed so that if they get loose in a flood and hit something, they'll crumple and sink.

Like I said, they're only slightly thicker than dumpsters. An inner floaty box with an outer bumper.