about water pressure

**Chitose** · Nov11-09, 07:07 AM

Hello, Chitose the curious chick again.

This is not my home work, but something I keep wondering since I watch movie 'The Abyss'.
http://en.wikipedia.org/wiki/The_Abyss

first the picture. (I draw it with photoshop, hope you guys don't get confuse)

And the question.

I wonder which zone that I can swim safely without being crush by water pressure?

I know that 'zone A' is safe, but why? as long as I have air around and above my head, no matter how deep I am water presure can't harm me?

I know that 'zone D' is DEAD zone, so out of the question.

what about 'zone B' and 'zone C'?
'zone B' have Steel panel surrounding it, 'zone C' have entire structure cover above it.

I'm not sure if water pressure is squeeze object form up to down cause of water weight or from all direction?

Does zone A, B and C have much different in water pressure? If i'm in 'safe zone' and point my finger through 'Dead zone', what gonna happen? can I feel light pressure to heavy pressure in just a few centimeter?

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P.S. English is not my native language, so please forgive me If i'm wrong in gramma or spelling.

P.S.2 I can't use Technical word by myself, but I can understand when you guys useing it, don't worry

**Danger** · Nov11-09, 07:14 AM

Hi.
Unless there's an airlock system in place, the pressure is equal in all areas. All zones are therefore equally safe. If there is an airlock, and the air pressure is lower than the external water pressure, you would have to undergo extensive decompression to re-enter the habitat. Having air around your head has nothing to do with it, other than allowing you to breathe without respirator gear.

**J.ofalltrades** · Nov11-09, 09:17 AM

I see what Danger is saying. The pressure inside the underwater lab is high enough to keep the water from flooding, therefore your body is already accustomed to the pressure. So swim all you want, just as long as you don't swim immediately from the underwater lab's pool straight to the surface. I think the safe rise rate is somewhere between 60 - 30 feet per minute, and the deeper you are, the faster you can rise from the deepest parts. Meaning the closer you get to the surface, the slower you should go from a deep dive.

**Chitose** · Nov11-09, 12:38 PM

So umm... If my body is accustomed to the pressure of dept level , I'll become like fish? can swim through even in zone D than?

**James Leighe** · Nov11-09, 12:56 PM

Originally Posted by Chitose

So umm... If my body is accustomed to the pressure of dept level , I'll become like fish? can swim through even in zone D than?

What he meant is that all areas are equally UN-safe, the pressure would kill you pretty bad.

**Borek** · Nov11-09, 02:08 PM

Originally Posted by James Leighe

What he meant is that all areas are equally UN-safe, the pressure would kill you pretty bad.

Just like it killed Comex divers at over 500 meters back in eigthies... Wait. They survived, so something is wrong.

**James Leighe** · Nov11-09, 02:33 PM

Originally Posted by Borek

Just like it killed Comex divers at over 500 meters back in eigthies... Wait. They survived, so something is wrong.

Fair enough, but would a diver survive at 1000 meters? I don't even think 500 meters would be very pleasant...

"In 1992 Comex diver Theo Mavrostomos achieved a record of 701 MSW (2300 ft) in an on shore hyperbaric chamber. He took 43 days to complete the dive."

Extremely impressive, but I would like to see him go 1km. He needed a hyperbaric chamber and ~22 days of slow progress to get to 2300ft (~700 meters). Either way it's seriously pushing the limit at the least.

EDIT: It's awesome by the way that the OP drew a picture for us!

**Borek** · Nov11-09, 02:55 PM

Very likely at higher deeps there will be effects we are not aware of yet - I think I remember reading that at 100 atm cods lost haemoglobine from the red blood cells or something like that - so there are possible problems that we have no idea of.

However, I was just pointing to the fact that high pressure doesn't have to be dangerous. I feel like OP has some misconceptions about the pressure and its effects.

**Chitose** · Nov11-09, 05:50 PM

Okay, back to question. I'm bit confuse here

I didn't dive straight from surface like comex diver.

I'm in that facilities, and my body are accustomed to air pressure inside.

I jump into pool in zone A, I'm sure I'm safe (assuming that I can endure to any low temparature)
and if I'm dive to zone B, C and D

what happen?

which zone that water pressure gonna kill me?

water pressure canbe so different in just a few yards?

**James Leighe** · Nov11-09, 05:57 PM

Originally Posted by Chitose

Okay, back to question. I'm bit confuse here
I didn't dive straight from surface like comex diver.
I'm in that facilities, and my body are accustomed to air pressure inside.
I jump into pool in zone A, I'm sure I'm safe (assuming that I can endure to any low temparature)
and if I'm dive to zone B, C and D
what happen?
which zone that water pressure gonna kill me?
water pressure canbe so different in just a few yards?

Well, we are not sure it would kill you...

Either way the pressure is the same everywhere in your drawing. So if your gona die in one zone, all zones are deadly. (even the one with air, since the air has to push agensed the water (with equal force) to keep it from flooding into the 'research facility')

Here is a drawing:

The idea here, is that the two arrows (of pressure) MUST be equal, so everywhere is super high pressure.

**Danger** · Nov11-09, 06:03 PM

I think perhaps the problem here is that your zones are ill-defined. All water and or air at an equal depth is at equal pressure (within the parameters of your diagram). Your zones should be differentiated vertically rather than horizontally. As shown, the pressure in zone B will be higher than the pressure of zone D that is parallel to zone A.

edit: Hi, James. You sneaked in while I was composing. Nice example. My only disagreement with it is in reference to what I just posted. The pressure won't be exactly equal at varying depths.

**russ_watters** · Nov11-09, 06:04 PM

Originally Posted by Chitose

Okay, back to question. I'm bit confuse here

I didn't dive straight from surface like comex diver.

I'm in that facilities, and my body are accustomed to air pressure inside.

I jump into pool in zone A, I'm sure I'm safe (assuming that I can endure to any low temparature)
and if I'm dive to zone B, C and D

what happen?

which zone that water pressure gonna kill me?

water pressure canbe so different in just a few yards?

Again, as long as you don't go up or down by more than a few yards, the pressures in all of those zones are very close to equal, so you will notice no difference in swiming from one to another.

**russ_watters** · Nov11-09, 06:06 PM

Originally Posted by Borek

Very likely at higher deeps there will be effects we are not aware of yet - I think I remember reading that at 100 atm cods lost haemoglobine from the red blood cells or something like that - so there are possible problems that we have no idea of.

However, I was just pointing to the fact that high pressure doesn't have to be dangerous. I feel like OP has some misconceptions about the pressure and its effects.

Certainly at 1000m you can no longer breather air (the oxygen at that pressure will kill you), but there is probably a mixture of gases that would be breathable.

**Borek** · Nov11-09, 06:59 PM

Originally Posted by russ_watters

Certainly at 1000m you can no longer breather air (the oxygen at that pressure will kill you), but there is probably a mixture of gases that would be breathable.

Yep, probably something similar to trimix. Or something not similar

**Count Iblis** · Nov11-09, 07:47 PM

Sperm whales can dive to a depth of 3 km

http://en.wikipedia.org/wiki/Sperm_W...ion_and_diving

**Chitose** · Nov11-09, 08:51 PM

Oh I get it, If there are an open hole direct connect to water, air inside that room must equal with water to prevent from flooding.

So, the movie is pure fantasy than? or 1,000m is just too deep?

If we increase air pressure bit by bit for body that can accustomed to pressure, how high human body can take?