Floating Cities [(C) Loren Petrich] I have a great idea for all those who hate government. They can always move to where there is no government at all. Where might that be, and what might be the most convenient places to live? If one succeeds, one can simply renounce whatever citizenship one has had, and live a life free from taxes and government regulations and other such things. In the first place, all of the existing land masses with the possible exception of Antarctica are out of the question. Some nation or other claims every landmass of any significant size with the above exception, and there are even those which have made claims to parts of it. If one turns from permanent to temporary solid surfaces, one enters into consideration the icecap over the Arctic Ocean. However, its mechanical strength is rather limited, limiting the size of habitats that can be constructed on it without turning it into the next solution to be discussed. In addition, both Antarctica and the Arctic icecap have the drawbacks of being very cold and of being very bad for surface transportation. Getting away from dry land, we notice that 3/4 of the Earth's surface is covered with water. Various nations claim sovereignty over various distances of ocean from shore; the canonical maximum distance being 200 miles (300 kilometers). Beyond that, one is outside the sovereignty of any government, with the possible exception of the United Nations. One's habitat will, of course, have to be either floating or on a very tall tower, as offshore oil rigs are; since the ocean depths are typically 5 miles (8 kilometers), one will need an extremely tall tower :-). Thus, we are left with flotation. One difficulty with that is that the oceans have currents, which can move one's habitat around. This can be gotten around by using anchors with *very* long cables, or else by moving the habitat with tugboats or even with some built-in propulsion. Where else? Underwater is a possibility, but neutral buoyancy would have to be continually maintained, or else the habitat will either float or sink. The ocean floors are good for hiding away, but they require strong walls for the habitat, because of the great water pressure. Underground? The difficulty there is that most nations make claim to what's below the surface they stake out. Disposing of excess heat is a potential problem there, because rock is solid and has a low thermal conductivity. The air? The square-cube law limits balloon size, and there is the problem that most nations claim sovereignty over the air above their territories. Outer space? Although one has a good energy supply (the Sun), there is the problem of the lack of air and the difficulty of getting supplies up from the Earth, which is necessary to get started in outer space. There are abundant supplies of water and other such essential, but volatile, materials in the outer Solar System, but getting there either takes years of travel time or the consumption of large amounts of rocket propellant. So we are stuck with floating cities for the time being. How may they be constructed? The most appropriate way to construct such a structure without running up outlandishly high costs is to try to use off-the-shelf components as much as possible. So one good source for the foundations of this city, for lack of a better word, would be barge hulls. Barges are typically rectangular-shaped, so it will be easy to tie together several barges. There is also the nice feature of modularity; more modules can easily be added to (or even removed from) the floating city as desired. Should the coupling be rigid or flexible? That is an interesting engineering question, and if the latter, there should be plenty of shock absorber (old tires might do nicely) in between the hulls. Supplies? The ideal would be to have a completely self-contained system, but in practice, that might be hard to achieve. But let us see what we can come up with. I propose that this floating city be able to support the sort of standard of living typical of late-20th-cy. industrialized countries, and not (say) the first settlers of the Pacific islands, whose technology was pure Stone Age. We must consider energy supplies, raw materials, food supplies, manufactured items, communications, trade, military, politics, and last, but not least, lifestyle. Energy? One approach is simply to import it, in the form of shipments of fuel oil. However, that is a serious departure from self-sufficiency, and it may be rather expensive, since the city's inhabitants would have to charter a ship or add the city to a ship's delivery run. An alternative is to produce usable energy at the site, and there are a number of technologies available. Solar energy is one possibility, but it is probably too dilute to be practical. However, there is a possibility which is IMO much better, Ocean Thermal Electric Conversion (OTEC) -- which uses the difference in temperature between the surface and the deep ocean to generate electricity with a turbogenerator. Since this floating city is intended for deep-ocean habitation, there should be no problem in getting the necessary temperature gradient. Since the deep oceans are near freezing, this setup will work best in tropical areas, whose warmth is desirable for other reasons :-). How much energy can feasibly be generated by OTEC will govern much of the rest of the floating city's operation. An abundance of energy will make possible various manufacturing and raw-material-recovery processes that will make the floating city very close to self-sufficient, as will be explained below; in what follows, I will assume this energy abundance. Raw materials? With sufficient energy, one can drive practially any resource-accumulation process. However, some resources are easier to accumulate than others. One can, in fact, get much, if not most, of what one wants from both the water and from the air. Fresh water is easy to obtain by boiling the water off of seawater and condensing it; one can also get table salt by this process. There are a variety of dissolved metal ions in seawater, and the rarer ones can be concentrated by carefully boiling the water from seawater, removing the condensed salts, and adding more seawater to the liquid part, which is boiled some more. Before long, the rarer metal ions in the liquid part get much more concentrated. This approach may be used to obtain such important nutrient ions as sodium, potassium, and calcium; phosphorus (in phosphate form) is relatively difficult due to its low concentration, but in theory, it can be done. However, phosphorus is a critical nutrient, and it can be obtained from catches of algae, plankton, and fish, unused plant and animal scraps, and even sewage; all that is necessary is to do some burning, and the resulting ash will contain the desired phosphorus. From the air, one can obtain carbon dioxide and nitrogen. One can collect the CO2 either by refrigerating the air until it condenses out or by bubbling the air through a tank of sodium and/or potassium hydroxide (lye). The alkalinity will force the CO2 to dissolve, and when enough has dissolved, the water can be boiled off to yield Na/K carbonate. This can then be baked to yield CO2. Hydrogen is easy to obtain by electrolyzing water. Nitrogen compounds can be obtained either by the Haber Process (combining nitrogen and hydrogen under heat and pressure with an iron-oxide catalyst to produce ammonia) or by making electric sparks and washing out the resulting nitrogen oxides. Carbon dioxide can be used as a feedstock for making (among other things) liquid combustible fuels and raw materials for plastics; all that is necessary is to combine it with hydrogen with the help of a catalyst, and one can get (for example) methanol or even some hydrocarbons. The liquid combustible fuels may be critical for the mobility of the floating city, since it will probably need to be towed by tugs; since most tugboats run on various combustible liquid fuels and not electricity supplied from outside. Some boats may use diesel-electric engines; it ought to be straightforward to connect the OTEC generators to the tugboat engines if that is the case. If it is necessary to hire some outside company to do the job, the floating city could supply all the fuel necessary, and could even produce enough fuel for payment for this service. Food supplies? At first thought, that might seem simple, because there are a lot of fish in the ocean. But the fish prefer to live in certain places, and it may be necessary to send out fishing boats to catch them. Also, a diet of fish might get monotonous. So farming might be necessary. All that is necessary is to reserve a lot of surface area for one's crop plants. Since they will not require more than a few feet of dirt, one can have a big area of rafts dedicated to farms. Alternately, plants can be grown on lower levels, with appropriate illumination, at least if the OTEC generators can produce enough electricity :-). Plants are surprisingly inefficient at utilizing sunlight; the efficiency is typically only 1% or so. This can be increased by supplying CO2, which will make the plants grow faster. The ultimate in fast growth can be achieved by growing algae in tanks filled with CO2-enriched water. One can have farm animals in addition to crop plants, but the predator-to-prey ratio, which is typically 1 to 10 or so, implies that raising a lot of livestock will be wasteful of the floating city's vegetative productivity. Manufactured items? There will have to be some on-board manufacturing of the more bulky items, if only to avoid importing them. However, relatively rare or very-durable items will be relatively easy to import, since one does not have to do much importing. The worst case, however, would be something that is commonplace and heavily consumed, but which would be difficult to manufacture in this floating city. Organic materials can be produced from biological sources (plant and animal material) or from the aforementioned CO2-hydrogen process; these can be used to make plastics and the like. Metals will be a bit difficult; the most common one will be magnesium, while some of the less common ones, like iron and copper, will require major seawater-extraction efforts. Glass seems like a very difficult case, but sand can be mined from beaches and turned into glass with enough heat. Wood would have to be imported, because this floating city would not be able to have a big forest on it. Paper would not be made from wood, but from fibrous plants. High-tech items, like computers, would definitely have to be imported. Communications? Receiving does not present much of a problem, since all one needs is a satellite dish and maybe some unscramblers. Although most communications satellites have a rather big transmission footprint on the Earth, the oceans are big enough so that this floating city may be out of some of the footprint. So one might have to arrange for some special arrangements with one of the satellites for that. That will also be necessary for transmitting, since over-the-horizon AM radio does not have sufficient bandwidth for sending pictures in anything approaching real-time. So to have at least one-way TV, to fax documents at a reasonable speed, and also to communicate with computers elsewhere in the world, it will be necessary to make appropriate arrangements with some satellite company. Trade? There will not be a whole lot that this floating city will be able to trade in, since it will be very isolated. It may be able to export OTEC-generated fuel to nearby islands in exchange for various supplies, for example, but it is unlikely that that will be very lucrative. However, there is one trade item that is much easier to transmit. Information. I note in passing that that has been the most successful commercial item for spacecraft for that very reason; consider communications and observation satellites. So what could this floating city do? It could be a major data repository and processing center; one which users could access via satellite in some reasonably transparent fashion; it could look like just another Internet site to Internet users elsewhere in the world. Furthermore, it can put the money in bank accounts in various places, such as Switzerland, whose geography is the exact opposite of this place's. Military? For this floating city to be taken seriously as an entity independent of every nation, it might have to have its own military force -- some sort of makeshift navy of some boats with various armaments. However, it will be surrounded by a very big moat, and that will keep out most potential threats. To get a big punch, it might be possible to buy some rather big-ticket weapons, such as cruise missiles or Scud-type missiles, perhaps even with nuclear warheads. Politics? Since the creators of this floating city will be wanting to get away from all governments, they will almost certainly have to declare this floating city a new nation, if only to satisfy diplomatic protocols. There is also the question of applying for United-Nations membership, or at least observer status. Even so, the freedom from all external government may prove attractive to those with anarchist tendencies, like those who hate taxes and regulations and so forth. However, on the inside, it may prove a bit difficult to maintain a community of virtuous anarchists. Lifestyle? There will be pluses and minuses. One big plus is being very near where one works; one does not have to commute a long distance every day, since all one has to do is walk or bike. However, some rather carheaded people might find this lack of driving a minus. This means more time for one's work, one's family and friends, and even oneself. Some minuses will be isolation from the rest of the world and being cooped up with a lot of people one may not like; there will be nothing but ocean for hundreds of miles outside of the boundaries of that city. However, computer-network access may at least partially make up for that.