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Posted: 6/12/2002 10:07:58 AM EST
Link Posted: 6/12/2002 10:13:34 AM EST
[#1]
Link Posted: 6/12/2002 10:16:35 AM EST
[#2]

hmmmmm....it's been many, many years since my basic SCUBA course, but if I remember correctly, for every 33 feet you descend, the pressure increases by 1 atmosphere.  So, at 40 feet you'd be at a little over 2 atmospheres of pressure, at 60 feet you'd be at almost 3 atmospheres....

Basically, what this means is that if you are sitting in 33 feet of water, take a full lungfull of air from a tank and ascend while holding your breath...then the amount of air in your lungs would double by the time you reach the surface....result would be a blown lung or an embolism....neither of which is desireable :-)
Link Posted: 6/12/2002 1:40:07 PM EST
[#3]
Quoted:
Water gains or loses .433 psi per ft.

HTH


gains going down, loses going up
View Quote

Going under is exponetial.
GG
Link Posted: 6/12/2002 2:38:31 PM EST
[#4]
Link Posted: 6/12/2002 2:41:40 PM EST
[#5]
14.7 psi at 33 feet
Link Posted: 6/12/2002 2:43:48 PM EST
[#6]
Link Posted: 6/12/2002 3:09:03 PM EST
[#7]
Isn't 14 and something psi the air pressure at sea level?
Yep I think its 14.7


Water info I remember from SCUBA diving
14.7 psi at 33 feet  =     .445 psi per foot
checks pretty close to
Polyaks answer
Water gains or loses .433 psi per ft.
Link Posted: 6/12/2002 3:17:22 PM EST
[#8]
Link Posted: 6/12/2002 3:25:02 PM EST
[#9]
No, the problems potentially arise in diving with pressurized air only.
Link Posted: 6/12/2002 3:38:23 PM EST
[#10]
Using these non SI units, and assuming that we're talking about fresh water:
[Edited because I really ought to express all units:"

34 feet of depth in water=1 Atmosphere,
1 Atmosphere=14.7 pounds/square inch (psi)

14.7psi/34feet of depth=.432 psi/foot of depth

So, at 40 feet:  40feet*.432psi/foot=17.28 psi
This is the gauge (hydrostatic) pressure.

The absolute pressure must include the column of air that is stacked on the water, so we add
17.28psi+14.7psi=31.98 psia (pounds/square inch abosolute)
Link Posted: 6/12/2002 3:40:35 PM EST
[#11]
1 psi per 2.3 ft. of water or 0.435 psi per ft of water.
Link Posted: 6/12/2002 3:53:51 PM EST
[#12]

Water pressure at depth is linear, because a liquid can’t be compressed.


About 32psi at 40 feet and about 40.5psi at 60 feet.


R/K
Link Posted: 6/12/2002 3:59:38 PM EST
[#13]

I should quantify that answer includes atmospheric pressure and like
IMHO pointed out, would be absolute pressure.


Link Posted: 6/12/2002 6:39:16 PM EST
[#14]
As mentioned before...
1 atm= 14.7 psi (sea level)
2 atm= 29.4 psi (33 feet deep)
3 atm= 44.1 psi (66 feet deep)
4 atm= 58.8 psi (99 feet deep)

This information was obtained from [u]Jeppesen's Open Water Sport Diver Manual[/u] that was given to me when going through my SCUBA lessons.  Hope this helps!!!
Link Posted: 6/12/2002 6:51:44 PM EST
[#15]
Link Posted: 6/12/2002 9:28:38 PM EST
[#16]
What has always puzzled me is to see fish swimming about in the oceans deepest waters and knowing at those same depths a steel hulled submarine would be crushed. I know there is a scientific/mathematical answer,  but It still amazes me.
Link Posted: 6/13/2002 3:44:19 AM EST
[#17]
Quoted:
What has always puzzled me is to see fish swimming about in the oceans deepest waters and knowing at those same depths a steel hulled submarine would be crushed. I know there is a scientific/mathematical answer,  but It still amazes me.
View Quote


I believe it's due to that the fish has equal  internal and external pressure. Whereas the sub requires 'air' within, hence the pressure difference.
Link Posted: 6/13/2002 4:05:43 AM EST
[#18]
Thank your Older_Crow.  Am-O-Tramp
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