@Normie Living on land tends to assume that you're allowing yourself to be subjected to the laws of your local government, which is what I'm trying to circumvent for the sake of functional anarchism.
That's because people have always lived only on land though. If living on water became the norm instead, there's no reason to believe that current practices and institutions wouldn't be carried over accordingly, for similar reasons and in a similar way. Now, if this was only a small community of a few thousand people at most floating around doing this, considered irrelevant wackos by the landlubbers, then maybe you could get away with it and just trade with/buy from land dwellers without being subject to any government. There are some fringe people who basically do this on land already (look up Slab City if you don't know what that is). If you're wanting to organize all of humanity this way, though, that would change things quite a lot.