You might be interested in the story of Radio Caroline, back in the '60s the BBC had a state monopoly on British radio and it was very stuffy and conservative. To get around this people used to set up AM transmitters and studios on ships just outside of UK territorial waters and transmitted from beyond the jurisdiction of the government. There were quite a few of these but Radio Caroline was the first and longest-lived - they lasted up to 1990 when the British government gave itself the power to raid radio ships in international waters (!) but it eventually returned with a license and is still around today.
While it wasn't exactly a dystopian floating city (quite the opposite, it was dedicated people who wanted to be there) it's still really interesting from lots of points of view I think.
Me too! One of my top-five records of all time. I was able to grab a pressing that had the original guitar version of "Radio Silence" - although I can appreciate the version that eventually ended up on later pressings I enjoy the guitar one so much more. I also saw him perform live in Baltimore pre-pandemic.
Reminds me of Radio Ceylon Hindi. All India Radio refused to play music that people actually wanted to listen to and it had a monopoly. Radio Ceylon filled the need and made millions from advertisements.
While it wasn't exactly a dystopian floating city (quite the opposite, it was dedicated people who wanted to be there) it's still really interesting from lots of points of view I think.