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Island Hub Seasteads?

Home Forums Community Dreaming / Crazy Ideas / Speculation Island Hub Seasteads?

This topic contains 8 replies, has 3 voices, and was last updated by Profile photo of Steffen Steffen 5 years, 11 months ago.

Viewing 9 posts - 1 through 9 (of 9 total)
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  • #1140
    Profile photo of JeffM

    Take everything I say in this post with a large helping of salt, because I’m unqualified to really propose this, but also take that fact into account while you write up a sharp critique 😛

    Anyways, another form of seastead that could be very useful would be one incrimentally built up around an island hub. There are small private islands you can buy for 1-3 million dollars a pop. I know that buying an island only makes you a landowner, but the point is that a few of these islands are surrounded by a lot of shallow water. These are small, unpopulated, private vacation islands.

    Depending on annual weather and other conditions geographically attributed to any one particular island (seasonal temperatures, hurricane potential, seismic activity, etc), I believe that an island would make an excellent starting point for a seastead community, where an initial seastead institute could be set up to co-ordinate various constructions.

    The islands would be big enough, and there would be enough shallow water to build structures which would be landed, even if under or partially submerged in the water. This could be go even further, and development of this hub area could be taken to subterranean levels (this will be touched on later in my post).


    Practice makes perfect. This kind of development would help engineers formulate methods which would benefit construction of underwater structures. At sea levels with acceptable pressure, it would help the seasteading institute to put research/resources into sub-sea level construction projects. I’ve looked over the cons of this concept in the beta book and I agree with the points listed, but I still think it is an avenue TSI should explore at some point.

    However, what I did not see listed in the list of advantages was that underwater structures would not have to move, unlike submarines and other vehicles which travel beneath the ocean. If I understand them correctly, a vessel like a submarine has to be constructed to enclose a certain amount of area and maintain a certain pressure, and both factors affect how deep the vessel can go. As well, a submarine’s hull can’t be made of ridiculously thick steel or titanium because there are mobility issues to consider (so a compromise is made between material and the pressures within and outside the submarine, the result of which will determine exactly how deep it is safe to go). An underwater structure would have no such mobility issues. So, what I’m basically saying is that an underwater structure has no practical constraints in terms of, “how thick should we make this?”.

    With the proper design, efficient and compartmentalized underwater structures would probably make an interesting venture for TSI. Above sea level solar and wind power could be used to power this kind of seastead community, both above and below sea level.

    These constructions would be extra expensive though, because of things like airlocks, and the conservative amount of material that would be used based on a construction based on its level below the sea (and the pressure associated with it).

    To be clear, am I not proposing this as a substitute for the idea of floating seasteads, only as an additional concept. A powered, built to last, underwater community (incrimentally built up around, preferably, an island hub) would in my opinion be in the interests of a normal seastead at an advanced point in its development (assuming such a seastead would have nearby, below sea level areas that were at an acceptable depth, or maybe even an island).

    I know that this leads to questions of whether or not you would be allowed to secede with an island and what kind of backlash it might invite from the local government, but the islands I’m talking about are really inconsequential. No populations besides the owners and employees (although I doubt that would matter anyway).

    Longterm Development and Resources:

    Underwater constructions could, in my opinion, greatly benefit a sea city-state. Mainly, they could provide very useful mining opportunities that would decrease a seastead’s reliance on importing manufactured construction materials from abroad (or will at least offer the seastead something more to make money from). Then there are possibilities in the generation of geothermal energy (expensive and time consuming, but will probably be very rewarding). In regards to the idea of mining, these subterranean mines could connect the subterranean levels of the island hub with the below sea level structures. If citizens living down there began to feel suffocated or enclosed, they could simply go to the surface. This would also make a very easy means of evacuating those citizens if a large amount of underwater structures/compartments were somehow compromised.

    A Few Additional Points:

    What I have said in regards to the relationships between an island hub and the underwater structures addresses or at least compensates for;

    Bad Failure Mode: The connections between the island hub and the underwater structures makes evacuation simple. A compartmentalized design would also help prevent the loss of any large sections (compartment evacuation and securing procedures would be essential to prevent loss of life)

    Psychological Difficulties: When off duty/on their free time, citizens could go to the surface via the tunnels/connections and get some fresh air if they felt the need. An open, visually pleasing design for individual compartments would be recommended (otherwise I know I’d go stir crazy).

    Difficult to Get in and Out Of: In regards to transport to the surface/sea level, this has been addressed in my previous point.

    Limited Access to Energy Sources: The connection with surface structures and the island hub would make it easy to integrate underwater structures with their wind and solar power means. Underwater structures would also open up a potential avenue towards geothermal energy (if they chose to utilize it).

    So, the model I’m proposing is essentially a mix of a small land hub (and a few additional structures), perhaps some flexible, floating ocean surface structures, subterranean levels and tunnels, and underwater structures.


    Profile photo of JeffM

    When I say compartmentalized (each floor and individual section designed so that they can be shut off from compromised compartments, until a leak is repaired the the water can be pumped out), I mean in a visually pleasing design, so that people won’t reject the idea of living below sea level outright. However this of course entails a much greater use of resources, and ultimately cash.

    Thats why I said in my above post that underwater construction ventures would have to be undertaken by a normal seastead in advanced development (at the point where it is an autonomous city-state).


    Hello JeffM

    Welcome to the community. A very interesting and “talkworthy” group of thoughts that you bring up here, thanks for that. The idea that it has to start somewhere on a location with people tooling around to test it out and make it happen has been poping up several times in this community. The Belize community was on the point of take off from a land based hub, OSDI was on the point of floating a couple of barges and houseboats out to link them together to a floating community in the florida keys. King is already afloat in Singapore on a aquaculture based project, festival like temporary float out happenings are part of the seasteading idea also.

    I also like your idea that submarine seasteading is kind of a natural development that should be pushed forward. It is a point that i also agree strongly with since our firm European Submarine Structures AB builds mobile and stationary habitats for exactly this purpose. (base info concretesubmarine.com) – it is clear that submarine housing has inmediate applications in tourism, but the concept goes far beyond with Phil Nuyttens vision of Vent Base Alpha (deep sea mining base) – a concept i did not find a lot of discussion about on the forums.

    Concrete shell building for submarine structrues is in use as we speak down to a depth of 300m, it can be applied to 600m without touching the field of “special concrete” – according to our investigations a depth of below 1000m and below can be explored. That is a lot of ocean to pioneer, mine, cultivate, house in.

    You also said that submarine seasteading would be expensive. I do not fully agree on that. We currently build floating and submerged concrete shell structure living space at a cost of 331Euro per cubic meter – this is average US and European housing cost.



    European Submarine Structures AB

    Profile photo of JeffM

    Hi, thanks for the reply.

    Thats a very interesting site, I’ll have to read up more on the use of concrete. Wouldn’t concrete be more liable to break down and deteriorate over time, or is it given a coating of some kind? I’m not an expert so feel free to point it out if I’m completely wrong =]

    I always pictured a long-term, underwater structure as being a number of sizable, custom modules, the outsides of which made out of steel (or stronger materials).


    Definitly concrete is the most durable and most suitable structural building material for floating megastructures – the oil and gas industry is going away from steel platforms toward concrete platforms and barges.

    The general opinion is that a floating concrete shell structure will last 200 years maintenance free.

    This is far beyond what you can get from steel (2-3 years). You might want to check a comprehensive status report at ( ref: concrete offshore structures ).

    In fact the biggest man made permanently dived shell structure is -TROLL A -at a depth of 303m ( ref: Troll_A_platform) – a condeep concrete structure. The biggest existing barge is the -nkossa barge- a concrete barge (ref: nkossa barge) . The oldest concrete shell structure still standing is the pantheon in rome – a concrete dome structure of some 2000 years of age – still in great shape today. ( ref: Concrete_shell_pantheon)

    I agree about the modularity of underwater structures – in fact underwater tunnels are already using this principle on a dayly base. They are built as segments, floated out, connected to the other segments by divers, forming a multi-segmented tube under the sea – so there is not much new to invent for building a submarine seastead – submarine tunnels and floating bouyant tunnels do already exist and are state of the art in civil engineering. (ref: submarine tunnel segment bosporus)

    For a submarine seastead i would go for sphere segments with flat mating areas rather than tube segments.



    European Submarine Structures

    Profile photo of Steffen

    For a submarine seastead i would go for sphere segments with flat mating areas rather than tube segments.

    Hi Wil

    English is not my primary language. Can you explain what you mean by “mating areas”? I guess you are not referring to this: http://en.wikipedia.org/wiki/Mating


    The expression “mating area” is used for submarine rescue missions, the submarine has a flat area around the hatch where the rescue vessel can dock and create a seal, so the crew can be tranfered to the rescue vehicle without being exposed to the water pressure. The benefit of a flat area as “mating area” is, that vehicles of different size, make and hatch design, can get a seal as long as the contact area is just flat. So having a “flat area around the hatch” is the only “standardisation” that is needed to get segmented submarine seasteads linked together.

    Profile photo of JeffM

    I think what he meant by mating was that within each spherical segment, there would be living/work areas which would connect and be flat, so in a sense be ‘mating’ (since being a part of individual modules, those flat areas once connected would be considered counterparts, i.e mating).

    Profile photo of Steffen

    Thank you for your explanation, Wil. I find your submarine ideas very interesting.

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