I'm not getting how pressure affects the seamoth and myself

[Sir Prometeus]

I'm still playing around 200m max, but at that depth, the seamoth starts to break by the pressure. Surprisingly enough, my character can swim at that depth not giving a f**** and then swimming upwards to enter the seamoth.

What's the logic behind this?

[Matias]

your suit is immune to pressure. for some reason , as for the seamoth , thats why you have pressure compensators.Once you have somethings , you can swim at 1.5Km down easily with your suit

[Waxfire]

The vehicles like the seamoth, have a pressure break point and one at which they are more vulnerable.

The player itself is immune to pressure, seems like he got a really good survival suit :) Only thing in highter depths is an increase in air consumtion which can be lowered by a rebreather.

[Lord Of Dorkness]

Originally posted by Waxfire:

The vehicles like the seamoth, have a pressure break point and one at which they are more vulnerable.

The player itself is immune to pressure, seems like he got a really good survival suit :) Only thing in highter depths is an increase in air consumtion which can be lowered by a rebreather.

Acceptle breaks from reality, and easily explained awawy given the sci-fi setting, I'd say.

Don't get me wrong, stuff like gas-mixtures, CO^2 saturation, deep preasure suits and other stuff real divers have to consider are all really interesting, but it's also really, really complicated. If Subnautica tried to incorporate a more simulation like approach it would probebly be quite neat, but it wouldn't be the same game anymore.

...I would like to at least try that game, though. I'll admit that.

[Twilight]

Let's do a reality check with physics:
Air filled stuff like submarines compresses the deeper you go.

The human body largely consists of water, so it handles pressure quite well. Only problem are the lungs: But your oxygen bottle provides you with air with a pressure from the surrounding. That way you can breath with normal lung movement.

[tranceology3]

At first, I was surprised by this too. But then it made sense; more air, more need for a pressure compensator. The suit he has is very advanced, and later on, your subs will become even more advanced to go at further depths. Remember you are trying to build advanced tech from blueprints scattered all over the ocean. The tech is there, it's just you need to find it to build it.

[Sir Prometeus]

But if your air tank gives you pressurized air to compensate pressure in your lungs, why can't your seamoth do the same?

[Lord Of Dorkness]

Originally posted by Sir Prometeus:

But if your air tank gives you pressurized air to compensate pressure in your lungs, why can't your seamoth do the same?

Well, you're suit can store... What, 35 seconds by default without a tank, right? So it's clearly some sort of survival suit, quite possibly originally intended for short-term vacum exposure.

It's hardly impossible that you simply don't have the materials that 'air suck/purification' system is made from. It's extremly efficent for its size, after all, and if nothing else your PDA was damaged in the crash.

[Alpha393]

The seamoth is a glass bubble. Not enameled, reinforced, bulletproof glass. Just plain glass. Your jumpsuit is designed to handle a vacuum for a brief amount of time if need be.

[Grim]

Originally posted by Twilight:

Let's do a reality check with physics:
Air filled stuff like submarines compresses the deeper you go.

The human body largely consists of water, so it handles pressure quite well. Only problem are the lungs: But your oxygen bottle provides you with air with a pressure from the surrounding. That way you can breath with normal lung movement.

This.

Human beings are mostly water. We can go to almost any depths. Temperature is a bigger threat to us then pressure. That's why it takes us time to decompress, our biology adjusts.

[Twilight]

Originally posted by Sir Prometeus:

But if your air tank gives you pressurized air to compensate pressure in your lungs, why can't your seamoth do the same?

Oh, nice question. It got me thinking for a bit :)
Thats my (quite possible) answer considering physics:

As the human, you start with a bottle with a fixed amount of breathable air (whatever mix). That is setup before you dive. Usually a bottle has a amount of 200 bar compressed gas in its fixed bottle volume. Thats the thing you can consume, depending on depth.

Even if, lets say, the drivers seat cabin is filled with water (quite uncomfortable!) and thus the glass section can withstand any surounding pressure i think any machine needs to have some air filled parts/compartments to work. This would result in a pressure sensitive area and therefore needs a pressure resistant shielding.

Or, how you correctly remarked, an inside pressure matching the outside pressure.

Short insertion:

At sea level, air pressure is 1 bar
10m down: 2 bar water pressure, your lung volume would be half the size compared to 1 bar ( if not 2 bar worth of pressured air would be given to you)
20m down: 3 bar
...
190m: 200 bar -> you could only afford a few breaths of 190th your normal lung volume, then the bottle is empty

( Small insertion: this is where a rebreather handles things completely differently!)

If you dive up, you have to consider that the air in your lungs is now expanding. Thats why divers have to have their lips slightly open to let the overpressure out when diving up. Otherwise you will die of severe lung tearing. Not good. Unpleasant way to go, too.

So, considering that, how does it look like for any machinery as a submarine?
The mechanism is the same, so for any compressible (ideal) gas (air) filled compartment, you have to consider the compression/decompression when changing height/depth.

If we, lets say spec our hypothetical submarine for 190m depth, that cabin would be 190 times the size at surfaced level. What a nice explosion!
And because the machines have to handle these gas expansions you would need a mechanism to not only spend air, but also recompress air when diving up. This is heavy machinery, needs big tanks, uses a lot of power with every height change, etc. *And* you will get fixed to a certain dive depth, and no further meter down.

So i assume they leave that equipment to keep things simple and failsave, have a human-friendly interior of 1-2 bars air, with the cost that the cabin and its glass windows have to be pressure-resistant.

Buoyancy will be simply regulated with a (outside pressure) submarine's diving tank that is open to the sourrounding water and again - uses carried pressured air to blow the dive tank empty to gain height. A simple mechanism. Or, as the game is science fiction, some cooler way to get water out of the dive tank. A force field maybe. Or like a mechanical fish's dive bladder that can contract like a synthetic muscle.

For the real deal, how diving works on a WWII sub and still does nowadays, i recently found a cool instructive video:
https://www.youtube.com/watch?v=Ljr_t22oOmM

Regards,
Twi

[Twilight]

Originally posted by Alpha393:

The seamoth is a glass bubble. Not enameled, reinforced, bulletproof glass. Just plain glass. Your jumpsuit is designed to handle a vacuum for a brief amount of time if need be.

Well, that reminds me of an old joke:

Hey, a spacesuit should be also really good at diving, right?

Yeah, it handles everything from zero to 1 bar :D

[Sir Prometeus]

Originally posted by Twilight:

Originally posted by Sir Prometeus:

But if your air tank gives you pressurized air to compensate pressure in your lungs, why can't your seamoth do the same?

Oh, nice question. It got me thinking for a bit :)
Thats my (quite possible) answer considering physics:

As the human, you start with a bottle with a fixed amount of breathable air (whatever mix). That is setup before you dive. Usually a bottle has a amount of 200 bar compressed gas in its fixed bottle volume. Thats the thing you can consume, depending on depth.

Even if, lets say, the drivers seat cabin is filled with water (quite uncomfortable!) and thus the glass section can withstand any surounding pressure i think any machine needs to have some air filled parts/compartments to work. This would result in a pressure sensitive area and therefore needs a pressure resistant shielding.

Or, how you correctly remarked, an inside pressure matching the outside pressure.

Short insertion:

At sea level, air pressure is 1 bar
10m down: 2 bar water pressure, your lung volume would be half the size compared to 1 bar ( if not 2 bar worth of pressured air would be given to you)
20m down: 3 bar
...
190m: 200 bar -> you could only afford a few breaths of 190th your normal lung volume, then the bottle is empty

( Small insertion: this is where a rebreather handles things completely differently!)

If you dive up, you have to consider that the air in your lungs is now expanding. Thats why divers have to have their lips slightly open to let the overpressure out when diving up. Otherwise you will die of severe lung tearing. Not good. Unpleasant way to go, too.

So, considering that, how does it look like for any machinery as a submarine?
The mechanism is the same, so for any compressible (ideal) gas (air) filled compartment, you have to consider the compression/decompression when changing height/depth.

If we, lets say spec our hypothetical submarine for 190m depth, that cabin would be 190 times the size at surfaced level. What a nice explosion!
And because the machines have to handle these gas expansions you would need a mechanism to not only spend air, but also recompress air when diving up. This is heavy machinery, needs big tanks, uses a lot of power with every height change, etc. *And* you will get fixed to a certain dive depth, and no further meter down.

So i assume they leave that equipment to keep things simple and failsave, have a human-friendly interior of 1-2 bars air, with the cost that the cabin and its glass windows have to be pressure-resistant.

Buoyancy will be simply regulated with a (outside pressure) submarine's diving tank that is open to the sourrounding water and again - uses carried pressured air to blow the dive tank empty to gain height. A simple mechanism. Or, as the game is science fiction, some cooler way to get water out of the dive tank. A force field maybe. Or like a mechanical fish's dive bladder that can contract like a synthetic muscle.

For the real deal, how diving works on a WWII sub and still does nowadays, i recently found a cool instructive video:
https://www.youtube.com/watch?v=Ljr_t22oOmM

Regards,
Twi

Great explanation, I'm really grateful for it. However, I don't know if I got everything right.

At lesser depths, like 10 meters, your air bottle should last a lot, since it uses compressed gas to store more air in the same space, but since you have to fill your lungs at the same pressure of your environment, the deeper you go, the less your air reserve last, am I right?

However, a Seamoth with a limited supply of air should work the same way. But a seamoth could carry a slightly bigger and slightly better air tanks and CO2 recyclers than a scuba diver.

I get that in our game, the seamoth extracts air from its environment using energy, possibly due to electrolysis and using the nitrogen and CO2 it already contains to not to kill you with pure oxygen. But if they add want they have in mind, which is a seamoth with limited air supply by default, we should have a seamoth able to withstand depth much better, at the expense of a limited supply of air, isn't it?

[Twilight]

Yes, you are right. If you are less deep, the bottle holds longer.

Concerning the seamoth, well, we are not only doing a 5 to 30 minutes dive in shalllow water. We go deeper, and much longer. Thats a lot of air. So even if it has the machinery, compressors, tanks and whatnot i still would also say it has some 'dry' parts that have normal air.

Well, thats speculation. It depends on the construction. But as soon you have one tiny bit of equipment that is pressure sensitive, the whole sub will have a depth limit too.

And thats independent of how it works for the body.

But to think the other way round again, Lets say, we build a Sub that is speced for 200m. So we start of with an inside pressure of 190 bar. Ok, but usually we also begin the dive with the submarine at shallower depth. Suddenly the inside pressure is much higer than the outside. So if we dive up, we risk explosion, or the sub has to be built like a tank.

So i think its just simpler to have the boat built for higher pressure outside. You can harmlessly surface up, because the only thingthat can happen is that the pressure outside is lower.
Not with the construction that we pump full of high pressure air before we go down :D
But again, you could rightfully argue, that an equalization mechanism could prevent this, and store excess air in a special sub tank. But then again you have to know *beforehand* how much pressure you need and that is again a depth limit.

Besides, someone also has to get inside that sub. And below 42m (around max. sportsdiving depth after diving tables) you risk already oxygen poisoning and nitrogen narcosis.
So if you get into that boat. that is already like a 200m depth dive but already at sea level, that would be quite a shock to the body. And you usualy also take time to dive down with a boat too. So in that time you would aready suffer all the consequences that are involved with higher inside pressure.

I guess it much more safer and simpler to do it the other way round. With the inside normal pressure, so the body won't be affected by any depth effects. Having the inside also with 200 bar, will kill you eventually.

[Cougarific]

Originally posted by Alpha393:

Your jumpsuit is designed to handle a vacuum for a brief amount of time if need be.

Yah read the description of your suit in your Encyclopedia. It explains that the suit is designed to work in any pressure from vacuum to deep sea.

[Nanostrike]

Originally posted by Alpha393:

The seamoth is a glass bubble. Not enameled, reinforced, bulletproof glass. Just plain glass. Your jumpsuit is designed to handle a vacuum for a brief amount of time if need be.

This is completely the case. The Seamoth isn't designed as a deep-sea exploration vessel at all. It was designed for zipping around in relatively shallow waters to survey, explore, and carry samples. You're literally improvising equipment to push it far beyond it's normal limits.