I've been following the Seasteading Institute since it has been in existence. I grew up on the water in New England and spent my summers teaching sailing, exploring the estuaries to collect crabs and mussels and even making the occasional sand castle or two .
It seems to me that most people on the seasteading institute group are focusing on platforms for creating artificial land. I also grew up with family in Biloxi Mississippi. Has anyone here visited there before Katrina? There were many many many floating casinos and hotels on your typical barges. Post Katrina, well, Biloxi was basically a heap of trash everywhere. Blocks and Blocks inland were now filled with a mix of sand, debris, and casino pieces.
With that in mind, when I first found that the idea was cement barges, I just shook my head. In the open ocean environment off of San Francisco, that would be a terrible idea, while weather and seas are maybe sorta stable, what if something unexpected happened? What if a Tsunami happened and shifted the seafloor resulting in even a 10 foot wave coming to say hello to the structure? Well most of the designs would basically fail.
That, is troubling for many a reason.
I'm proposing something slightly different. You see, life in the sea and in the air doesn't think how us Humans do. We think in terms of linear area. While the fish and the birds are not restricted to our two dimensional thought process but three dimensions. I like to think of it as thinking volumetrically.
When thinking volumetrically, biomimicry is much easier.
When looking at the great oceans, it is easy to notice certain things. Fish form balls, Ice floats, and well the water gets deep.
The most efficient way to build volume is as many have noted on here and elsewhere is with a geometric dome. I'm suggesting the Geodesic sphere be the standard for which things are built for "seasteading." In addition to the strength and material per volume, it is also extremely efficient in terms of stability with an environment with potential extreme weather.
I'm suggesting that these Balls, be tethered to a weight, and or use a ballast. This would stabilize the bottom point, but also allow for the submergence of the structure. Yes, I'm suggesting that we build spherical submersible dwellings. This way a breakwater is less needed. In the case of a bad storm or extreme waves, the structures can go underwater to take a gentler ride through the disturbance. Similar to a surfer diving under the passing wave.
Depending on the ballasts the structures could be at a variety of depths and waterlines. It does complicate the systems initially, but allows for much more resilience, also, extremely easy to rearrange and move said structures by towing.
I have spoken directly to the individual who makes the GIANT open ocean fish pens that people have mentioned on here from time to time, and he believes that his structures could be modified for my use case scenario. Each section between supports can be customized as well, be it an access hatch, or a tow point, a window, or really anything you can imagine.
Cost for an initial test unit is somewhere between $25,000 for just a shell to upwards of $2.5 million for a large stadium sized structure that could be used both for residential and commercial.
Anyways, these are some unpolished thoughts. It doesn't seem that the forum is very active. Maybe It is filled with people and I can't find the threads, or maybe everyone on here has never sailed a boat before. Needless to say, I believe trying to make a floating city is foolish, but a group of spheres very functional.