Which can be called a "seastead" according to professor Petrie’s definition?

F: Have you ever dreamed of living on a man-made island away from the hustle and bustle of big cities? Is it possible and what are the pros and cons? This is New Ideas Today with me Zeinab Badawi. Talking about it tonight is George Petrie, a former professor of naval architecture at the Webb Institute in New York. Welcome, professor Petrie. It’s kind of like sci-fi scene living on an island built by humans, isn’t it?
M: You may find the idea a bit futuristic, but it’s not completely crazy. First of all, I would like to introduce the idea of "seasteads". (1) Seasteads are new cities on the high seas, like you said, man-made islands. Large maritime structures that resemble seasteads already exist. We already have giant cruise liners host thousands of guests on lengthy voyages in luxurious surroundings. There’s also offshore oil platforms providing floating accommodation for hundreds of workers amid harsh weather and high waves.
F: If we’ve already got something similar to, uh, seasteads why there aren’t any by now?
M: The examples that I gave, cruise liners or offshore oil platforms falls some way short of the permanent, self-governing and radically innovative ocean-based colonies imagined by the seasteaders.
F: Seasteaders?
M: That’s people who dream of living on seasteads. (2) To realise their dream they must overcome some tricky technical, legal and cultural problems.
F: What are the technical problems? Since similar structures already exist, I don’t expect to be faced with many of that.
M: Seastead designs have three categories: ship-shaped structures, barge-like structures based on floating pontoons and platforms mounted on semi-submersible columns, like offshore oil installations. Ship-shaped structures can pack in more apartments and office space for a given cost than the other two types of design, but they tend to roll in choppy seas. Pontoon-type structures, or giant barges, are the cheapest of the three options, but they are even more vulnerable than ships to choppy seas. (3) Structures built on floating columns are the most rugged, but they are more expensive than ship- or pontoon-type vessels.
F: So the tendency to roll of the first two structures and the cost of structures built on floating columns are the drawbacks.
M: Yes. Even once a viable blueprint for the structure of a seastead is produced, the technical challenges are not over. The more it relies on land-based supplies of fuel and water, the more dependent it will be on existing governments. Since seasteaders are the libertarians dreaming of escaping the evil ways of governments, it’ll be thus harder to achieve their dreams.
F: OK. Would you tell us something about the legal problems seasteaders will have to overcome?
M: The limit of countries’ territorial waters is 12 nautical miles offshore. (4) So, if they don’t like the control of the governments, they should build seasteads more than 12 nautical miles offshore. But building too far from the land can make travelling to and from the seastead too long. And the laws of the sea give countries powers to enforce some criminal laws up to 24 nautical miles out and to regulate some economic activities in a 200-mile "exclusive economic zone".
F: It’s by no means easy to escape the invisible hand of governments.
M: Right. Until the legal problems can be solved, they won’t realize their dream even if there were no technical problems.
F: You also mentioned cultural problems. What are they?
M: For example, how should seasteads attract enough people to live on it? After all, there’re not many seasteaders. Every place should have a unique culture to its own, if seasteads can’t provide it, why on earth would people give up their city lives? Linguists quip that a dialect is a language without an army and a navy to enforce its status. Seasteads may end up as wannabe sovereign states without the means to defend their autonomy against land-based governments.
F: Given all these problems, do you think that it’s possible to solve them?
M: I’m confident enough. If some people are willing to try it out, that is. (5) Nobody anticipated the immense variety of uses that would be dreamed up for the internet, yet it has become indispensable to our daily life. All that is lacking is for the first one to go into the water and say, "Hey, come on in, the water’s fine."
F: Nice words there. Maybe it’s not a distant dream. Thank you for joining us.
M: You’re welcome.
F: Time to wrap up today’s programme. We would like to hear from you. What do you think of seasteads? Email us at newideastoday@bbc.co.uk. Thanks for watching and have a lovely evening. Bye!