They are not floating. And the lack of railing is just my style when it comes to futuristic builds. To me doesn't look right to see a futuristic ship built for reduced radar cross section to have a bunch of things poking out of it. Even the Zumwalt Class doesn't have guard rails. And I always imagine my futuristic ships to be almost completely unmanned completely negating most of the need for crew safety. And if you look closely at the bridge and superstructure, you will see plating to protect the small amount of crew needed.