Random thought of the week, underwater edition

Just thinking about weird stuff today. Why don't we build underwater?

Obviously the pressure is kind of a problem, and salt water is rather corrosive. No natural light isn't great either. 

But for hypothetical thought sake, let's say 500 feet under. That's 15.15, call it 15, atmospheres or 228psi. Kind of a lot, but we send submarines and way more technical stuff way deeper all the time. It's also available in a freshwater flavor in a few places. 

Now I would think you'd want a tether mount versus building directly on the sea floor Because stuff is always in motion underwater. It would be a neat trick to use that as a power source though. 

What do you build with though, that would last 50, 100, 500 years? Plastic? Concrete? Metal? Concrete seems the most durable, judging by all the ancient civilisations we've already found under water, but those aren't currently able to be occupied. 

But how would you build something like that out there? Even with today's technology, an aircraft carrier, a couple dive teams, and a big ass 3d printer could build on demand on the ocean surface, then drop it to level. 

Power has plenty of options, nuclear probably the easiest, but tethered floating solar or wind  farms, wave generators, there's other options. 

What's stopping it from happening? How would you do it?

I think the big issue is just expense.

You would need to build every single utility and life support system AND have crazy redundancies.

Waste water, fresh water, air, etc. 

Why so deep?  

I realize this is a thought experiment, but what problem would this solve?

I'd vote for coated steel.  Easy-ish to repair.  Fairly cost effective.  Strong, etc.

What do we stand to gain?

We're not running out of land, we're just running out of convenient land but what you're proposing would be much less convenient.

In reply to RX Reven' :

We already build underground bunkers and shelters and apartments and houses, why not? We've built whole islands just for something to do, and airports. We've got companies trying to put hotels into orbit at this point.

But really I have no real reason other than being bored on a Friday afternoon, just seemed odd to me that we pretty much ignore ~75% of the planet. 

Floating cities are cool but played out, I can get an airbnb tree house in the Amazon, there's the kilometer city Saudi or whoever is building in the middle of the desert, so why not the ocean?

Bioshock style I guess. 

In reply to RevRico :

90% of my issues with my house are due in part to water incursion. 

That is all I have to say on the subject. 

RX Reven' said:

What do we stand to gain?

We're not running out of land, we're just running out of convenient land but what you're proposing would be much less convenient.

We aren't though. 40% of the population lives in a coastal county even though it's less than 10% of the land area. This is just the US of course. 

Many don't want to live in a "flyover state," but that doesn't mean they aren't convenient in the sense I think you mean. 

This is kind of like asking why we don't replace freeways with 80 mph conveyor belts.

The technology exists, sure, but it costs a whole lot more, is very inconvenient, imposes a lot of risk (ever looked at survival rates for submarine accidents?  It's not good), and most importantly doesn't really solve any problems that we actually have.

It appeals to the '70s teen sci FI buff in me. 
Practical. Probably not. 
Never stopped homo Saipan before. 

RevRico said:

In reply to RX Reven' :

We already build underground bunkers and shelters and apartments and houses, why not? We've built whole islands just for something to do, and airports. We've got companies trying to put hotels into orbit at this point.

But really I have no real reason other than being bored on a Friday afternoon, just seemed odd to me that we pretty much ignore ~75% of the planet. 

Floating cities are cool but played out, I can get an airbnb tree house in the Amazon, there's the kilometer city Saudi or whoever is building in the middle of the desert, so why not the ocean?

Bioshock style I guess. 

Understood.

Let's start with where...we could make it a renewable power generation plant to provide the funding and the fine folks at GRM headquarters may like this as the fastest ocean currents in the world are found off the East coast of Florida and head Northwards.

This is a temperature map but it correlates well with current velocity:

 The red oval gets us both maximum current velocity and the 500' depth you're going for so this is my recommendation for the location:  

I remember reading somewhere about a hotel or airbnb or something that built underwater somewhere in the tropics, although it was only  like 20 or 30 feet below the surface.

edit:  It may have been this place, but there may be others.  It's a suite with part of it above water and a bedroom 16 feet below the surface.  https://www.hilton.com/en/hotels/mlehici-conrad-maldives-rangali-island/the-muraka/

Luxury living...

But berkeley that. Upkeep would be amazing $$$$.

In reply to stuart in mn :

$20k a night. Almost our entire years take home pay, for a single night. Plus all the travel to actually get there, so probably closer to our full yearly take home. 

I've seen it a bunch, and it always leaves me wanting to play the lottery. 

preach said:

Luxury living...

But berkeley that. Upkeep would be amazing $$$$.

If I had the money to buy a luxury submarine, the first thing I'd do is change the name from Migaloo.