The Campaign Builder's Guild

One of the recent talks regards expanding our cities to colonize the oceans, which many find to be more feasible than colonizing another body in space. So far, we have not gone as building a permanent, metropolitan establishment, but when that comes, some issues obviously need to be addressed.

Fishing and greenhouse farming have been considered, so finding food is not a problem.

Other problems are not so straightforward to solve. In the maximum depth of 500 feet, pressure is added, perhaps close to human tolerance, so what our main facilities need is an architectural shape best suited to withstand that kind of pressure. By deciding the three basic shapes--pyramid, box and dome--which one suits best?

In relation, glass does not react well to added pressure, either. That's why deep-sea diving submersibles have thick windows that are small in area and/or circumference. At a maximum depth of 500 feet, would a window in a permanent underwater city also need to be small and thick, too? If so, by how much?

Certain materials withstand pressure differently. Roman concrete has this unique ability to harden as it gets older and keep water out, which may explain how it has survived the past 2,000 years. Would this work in a marine city with a maximum depth of 500 feet, or would something else make for a more durable foundation?

Another problem is how to get a constant supply of oxygen. I could personally suggest planting each main facility with a chimney tall enough to break the surface, but is that feasible?

If one wants to spend the rest of his life beneath the surface, he would prefer to be dry. So how does one open and shut doors without drowning the entire corridor in the process?

The one final issue is finding fresh, drinkable water. I have no idea how that could be accomplished.

How would all those listed issues be addressed and solved?

Quote from: JohnWDaileyGLE
One of the recent talks regards expanding our cities to colonize the oceans, which many find to be more feasible than colonizing another body in space. So far, we have not gone as building a permanent, metropolitan establishment, but when that comes, some issues obviously need to be addressed.

Fishing and greenhouse farming have been considered, so finding food is not a problem.

Other problems are not so straightforward to solve. In the maximum depth of 500 feet, pressure is added, perhaps close to human tolerance, so what our main facilities need is an architectural shape best suited to withstand that kind of pressure. By deciding the three basic shapes--pyramid, box and dome--which one suits best?

In relation, glass does not react well to added pressure, either. That's why deep-sea diving submersibles have thick windows that are small in area and/or circumference. At a maximum depth of 500 feet, would a window in a permanent underwater city also need to be small and thick, too? If so, by how much?

Certain materials withstand pressure differently. Roman concrete has this unique ability to harden as it gets older and keep water out, which may explain how it has survived the past 2,000 years. Would this work in a marine city with a maximum depth of 500 feet, or would something else make for a more durable foundation?

Another problem is how to get a constant supply of oxygen. I could personally suggest planting each main facility with a chimney tall enough to break the surface, but is that feasible?

If one wants to spend the rest of his life beneath the surface, he would prefer to be dry. So how does one open and shut doors without drowning the entire corridor in the process?

The one final issue is finding fresh, drinkable water. I have no idea how that could be accomplished.

How would all those listed issues be addressed and solved?

(I will not make Bioshock references.... I will not make Bioshock references.... I will not make Bioshock references....)


Honestly, I think it's perfectly feasible to build an underwater city. Although for right now I could only imagine it being more like 200-300 feet in depth.

Architectural wise, I honestly could imagine a more cone like shape than a pyramid or a sphere. Cones are very hydrodynamic. It would'nt be hard for water to flow around it at all, which is what you want, other wise you wind up with a similar situation that skyscrapers face with wind.

I personally see more of a hydro-friendly plastic or polymer being used over concrete. Metal is out of the question, because all metal oxidizes.

As for oxygen, I think a chimney isn't a very good idea. You would have to have an oil rig like structure that connects to the city from the surface that acts as an air vintilation facility, and it had better be armed to the teeth, and protected like a tortoise, because if anyone attacked that place, the city would be suffocating rather quickly.

Salt water can be filtered, but from what i've researched, it's hard to do. But I imagine with the right incentives someone will invent a way to make it more efficient.

The only thing that concerns me is sun exposure. Humans can't live without the sun, believe it or not.

What about the glass?


What did you research on the saltwater filtration?


As for men without sunlight...https://www.youtube.com/watch?v=yVkyfC_AOLI

http://www.popularmechanics.com/technology/infrastructure/a17040/how-it-works-desalinating-ocean-water/
This is what it said about the big seawater filtration system.

As for glass, that's what I mean. Building the city from super strong plastics, and using clear plastic for windows.

Also an underground city would be a good basis for Bioshock 4.

"In relation, glass does not react well to added pressure, either. That's why deep-sea diving submersibles have thick windows that are small in area and/or circumference. At a maximum depth of 500 feet, would a window in a permanent underwater city also need to be small and thick, too? If so, by how much?"


You didn't answer that.

Quote from: JohnWDaileyGLE
"In relation, glass does not react well to added pressure, either. That's why deep-sea diving submersibles have thick windows that are small in area and/or circumference. At a maximum depth of 500 feet, would a window in a permanent underwater city also need to be small and thick, too? If so, by how much?"


You didn't answer that.

Fair enough. I guess it would depend on the glass. I don't know if any glass that could withstand the pressure over a wide, thin surface.

Are your questions formulated assuming access to current technology only, or are you interested in speculative/SF answers? Because if the latter I feel things get a lot easier. Water? That's what the hyper-efficient desalinating nanoporous membranes are for. The windows? Those aren't glass, they're ultra hard Gorilla Glass 13, except the ones made from synthetic diamond. Air? Haven't you seen our ventilation micro-wormholes to the surface? Or the hydroponic mega-parks full of bioengineered trees?

Quote from: Steerpike
Are your questions formulated assuming access to current technology only, or are you interested in speculative/SF answers? Because if the latter I feel things get a lot easier. Water? That's what the hyper-efficient desalinating nanoporous membranes are for. The windows? Those aren't glass, they're ultra hard Gorilla Glass 13, except the ones made from synthetic diamond. Air? Haven't you seen our ventilation micro-wormholes to the surface? Or the hydroponic mega-parks full of bioengineered trees?

Underwater security surveilance will be handled by the Genetically Enhanched Hyper Psionic Orcas. Why orcas and not dolphins? Because orcas

This thread is going to go in weird directions now, I can feel it.

Is there any particular reason why you'd need windows at all?  At 500 feet, light penetration is probably going to be rather poor.  There's probably not going to be a lot to see except dark water.

As for oxygen, it's estimated that 70-80% of atmospheric oxygen is produced by marine plants, and most of that is algae.  Instead of ventilating the city with a "chimney," you could produce oxygen internally with algae bioreactors.  This is already-existing technology, and all an algae bioreactor needs is sunlight (which you can produce artificially) and a little bit of plant food.  By placing these algae scrubbers throughout the city, you also avoid or at least diminish the need for the massive re-circulation system that you'd require if you were attempting to oxygenate an entire city through a chimney.  As an added benefit, you get to have bright green tubes/tanks/columns everywhere, which is pretty sci-fi looking if you ask me.  Who wouldn't want the hallways of their underwater city to look like this:



Desalinization is very energy-intensive, and we've also got to shine light on our algae continuously (not to mention our people), so this city really needs a highly productive and reliable power supply.  At the bottom of the sea, the only thing that seems to fit the bill would be fission/fusion.  Of course, the algae farms can also produce biomass for conversion into biodiesel very efficiently, but burning biodiesel requires yet more oxygen and I don't know if that would be too great a burden on our bioreactor system.  If it's in an appropriate zone you could get some power by putting pipes down below the seabed and tapping geothermal power, but it seems unlikely that this would be enough on its own.

"Is there any particular reason why you'd need windows at all?  At 500 feet, light penetration is probably going to be rather poor.  There's probably not going to be a lot to see except dark water."


500 feet is still within the Sunlit Zone.

Quote from: JohnWDaileyGLE
"Is there any particular reason why you'd need windows at all?  At 500 feet, light penetration is probably going to be rather poor.  There's probably not going to be a lot to see except dark water."

500 feet is still within the Sunlit Zone.

0.5% light at 330ft, that's basically nothing.

http://oceanscape.aquarium.org/explore/subecosystems/sunlit-zone

All that says is that light can reach 200m. Not how much, so that doesn't contradict my point. 0.5% of light is still above 0% of light.

500ft = 152.4 meters.

First Link: Below about 100 meters (approximately 330 feet), most areas of the ocean appear dark.

Second Link: Most of the visible light spectrum is absorbed within 10 meters (33 feet) of the water's surface, and almost none penetrates below 150 meters (490 feet) of water depth, even when the water is very clear.

As she moves downward, the UV, green, and violet wavelengths disappear, and the light becomes an intense, almost laser-like, pure blue.

So basically you have a miniscule fraction of light, only in the blue wavelength left.

0.53% of the surface light reaches a depth of 100 meters (330 feet) & 0.0062% of the surface light reaches a depth of 200 meters

So somewhere between 0.53% and 0.0062% of surface is the amount of light we're talking about.

Graph

So please, link me more.

Quote from: JohnWDaileyGLE
Fishing and greenhouse farming have been considered, so finding food is not a problem.

Aquaculture, greenhouses (probably aeroponics or hydroponics?), algae farms, seem like they could safely generate enough nutrients. Not sure how dense of a population it could support.

Quote from: JohnWDaileyGLE
Other problems are not so straightforward to solve. In the maximum depth of 500 feet, pressure is added, perhaps close to human tolerance, so what our main facilities need is an architectural shape best suited to withstand that kind of pressure. By deciding the three basic shapes--pyramid, box and dome--which one suits best?

A dome is the most structurally sound shape. A box and pyramid have their own issues. However this also all depends on materials and size.

Quote from: JohnWDaileyGLE
In relation, glass does not react well to added pressure, either. That's why deep-sea diving submersibles have thick windows that are small in area and/or circumference. At a maximum depth of 500 feet, would a window in a permanent underwater city also need to be small and thick, too? If so, by how much?

A window is a terrible idea, it's a structural weak spot. There would be so little to see at that depth that they would not serve a practical purpose. Better off putting LED screens that are connected to a camera.

Quote from: JohnWDaileyGLE
Certain materials withstand pressure differently. Roman concrete has this unique ability to harden as it gets older and keep water out, which may explain how it has survived the past 2,000 years. Would this work in a marine city with a maximum depth of 500 feet, or would something else make for a more durable foundation?

Concrete would not be a suitable material for this application. It would suffer from severe erosion. Other problems would be corrosion.

Quote from: JohnWDaileyGLE
Another problem is how to get a constant supply of oxygen. I could personally suggest planting each main facility with a chimney tall enough to break the surface, but is that feasible?

This would be unlikely to work. A 500ft shaft would have a large pressure differential between the top and the bottom. Due to this free flowing air wouldn't be enough to circulate the oxygen/carbon monoxide safely. A mine uses blower fans that suck air down. This would be feasible but power intensive. This also ignores the structural problems with a 500ft tower rising from the ocean floor. The best solution would be to have air scrubbers similar what the ISS or a Submersible uses.

Quote from: JohnWDaileyGLE
If one wants to spend the rest of his life beneath the surface, he would prefer to be dry. So how does one open and shut doors without drowning the entire corridor in the process?

This is actually pretty easy. Airlocks, just like on spaceships/the ISS. A lot of parallels can be found in space habitat design and underwater design.

Quote from: JohnWDaileyGLE
The one final issue is finding fresh, drinkable water. I have no idea how that could be accomplished.

Water filtration and recycling, like on the ISS. You can convert salt water to fresh water, however as Polycarp said it is expensive and power intensive. Perhaps the location of the underwater base is near a geothermal hotspot and can harness that for energy. Other solutions would be a nuclear reactor.

Didn't you read what I said about ROMAN concrete?  Also, if that's not the answer, then what material is?