Article in March 2006 issue of Scuba Diving

mike gray wrote:
> When you ascend from, say, 99 fsw to 66 fsw the pressure change
> is from about 59 psi to about 44 psi, a one-quarter reduction
> which will result in a 25% expansion of the air in yer lungs.
>
> But when you ascend from, say, 33 fsw to the surface the
> pressure change is from about 29.4 psi to about 14.7 psi and the
> halving of pressure will double the volume of air in yer lungs
> in the same 33 feet of ascent.

Good grief... isnt life so much easier with "1 bar every 10m", as
opposed to "14.7psi every 33 ft"?

Am sending an OW student down your way to Splashdown, btw. If someone
is there, asking for you to learn more about DIR, blame me for that :)

V.

VK wrote:
> mike gray wrote:
>
>>When you ascend from, say, 99 fsw to 66 fsw the pressure change
>>is from about 59 psi to about 44 psi, a one-quarter reduction
>>which will result in a 25% expansion of the air in yer lungs.
>>
>>But when you ascend from, say, 33 fsw to the surface the
>>pressure change is from about 29.4 psi to about 14.7 psi and the
>>halving of pressure will double the volume of air in yer lungs
>>in the same 33 feet of ascent.
>
>
> Good grief... isnt life so much easier with "1 bar every 10m", as
> opposed to "14.7psi every 33 ft"?

No. I can figger out in my head that it's 29.4 psi every 66
feet, but what the hell is it at 2 bar?

This is America! Speak American!
>
> Am sending an OW student down your way to Splashdown, btw. If someone
> is there, asking for you to learn more about DIR, blame me for that :)

I don't dive Splashdown any more.

VK wrote:
> mike gray wrote:
>
>>When you ascend from, say, 99 fsw to 66 fsw the pressure change
>>is from about 59 psi to about 44 psi, a one-quarter reduction
>>which will result in a 25% expansion of the air in yer lungs.
>>
>>But when you ascend from, say, 33 fsw to the surface the
>>pressure change is from about 29.4 psi to about 14.7 psi and the
>>halving of pressure will double the volume of air in yer lungs
>>in the same 33 feet of ascent.
>
>
> Good grief... isnt life so much easier with "1 bar every 10m", as
> opposed to "14.7psi every 33 ft"?

No. I can figger out in my head that it's 29.4 psi every 66
feet, but what the hell is it at 2 bar?

This is America! Speak American!
>
> Am sending an OW student down your way to Splashdown, btw. If someone
> is there, asking for you to learn more about DIR, blame me for that :)

I don't dive Splashdown any more.

VK wrote:
> mike gray wrote:
>
>>When you ascend from, say, 99 fsw to 66 fsw the pressure change
>>is from about 59 psi to about 44 psi, a one-quarter reduction
>>which will result in a 25% expansion of the air in yer lungs.
>>
>>But when you ascend from, say, 33 fsw to the surface the
>>pressure change is from about 29.4 psi to about 14.7 psi and the
>>halving of pressure will double the volume of air in yer lungs
>>in the same 33 feet of ascent.
>
>
> Good grief... isnt life so much easier with "1 bar every 10m", as
> opposed to "14.7psi every 33 ft"?

No. I can figger out in my head that it's 29.4 psi every 66
feet, but what the hell is it at 2 bar?

This is America! Speak American!
>
> Am sending an OW student down your way to Splashdown, btw. If someone
> is there, asking for you to learn more about DIR, blame me for that :)

I don't dive Splashdown any more.

VK wrote:
> sytech@yahoo.com wrote:
>> The point the author makes is that "the trickiest part of your dive
>> might come after the safety stop".
>
> In theory yes - as the biggest pressure gradient occurs in the
> shallowest few meters.
>
> That being said, I dont think too many people are getting bent coming
> up a bit too fast from 5m to the surface..

to me, bent is a long term effect.

the short fast ascent will not produce N2 effects,
but rather pressure effects,like pnemothorax,
Respiratory barotrauma, Air Embolism, Mediastinal Emphysema,

> Vandit
>

VK wrote:
> sytech@yahoo.com wrote:
>> The point the author makes is that "the trickiest part of your dive
>> might come after the safety stop".
>
> In theory yes - as the biggest pressure gradient occurs in the
> shallowest few meters.
>
> That being said, I dont think too many people are getting bent coming
> up a bit too fast from 5m to the surface..

to me, bent is a long term effect.

the short fast ascent will not produce N2 effects,
but rather pressure effects,like pnemothorax,
Respiratory barotrauma, Air Embolism, Mediastinal Emphysema,

> Vandit
>

VK wrote:
> sytech@yahoo.com wrote:
>> The point the author makes is that "the trickiest part of your dive
>> might come after the safety stop".
>
> In theory yes - as the biggest pressure gradient occurs in the
> shallowest few meters.
>
> That being said, I dont think too many people are getting bent coming
> up a bit too fast from 5m to the surface..

to me, bent is a long term effect.

the short fast ascent will not produce N2 effects,
but rather pressure effects,like pnemothorax,
Respiratory barotrauma, Air Embolism, Mediastinal Emphysema,

> Vandit
>

mike gray wrote:
> No. I can figger out in my head that it's 29.4 psi every 66
> feet, but what the hell is it at 2 bar?

Some comedian was going on about how single-minded the Chinese must be.
His argument was that they *had* seen shovels and pitchforks and so,
despite having realized the potential for a more effective eating
utensil, the fact that they stuck with chopsticks implied a certain
fixednes of purpose.

The Chinese, OTOH, claim that learning to use chopsticks as a child
helps develop not only physical dexterity but develops the brain
(probably through better motor skill development).

This is the scuba/US equivalent of chopsticks. My peanut brain cannot
handle all that stuff.

> I don't dive Splashdown any more.

Going for those 30-diver cattleboats, are you? Easier to meet chicks
there, though, I reckon.... my biggest complaint about diving with you
and Lee those years back was that neither of you is a hot,
large-breasted young lady... atleast, neither of you were back then.

V.

mike gray wrote:
> No. I can figger out in my head that it's 29.4 psi every 66
> feet, but what the hell is it at 2 bar?

Some comedian was going on about how single-minded the Chinese must be.
His argument was that they *had* seen shovels and pitchforks and so,
despite having realized the potential for a more effective eating
utensil, the fact that they stuck with chopsticks implied a certain
fixednes of purpose.

The Chinese, OTOH, claim that learning to use chopsticks as a child
helps develop not only physical dexterity but develops the brain
(probably through better motor skill development).

This is the scuba/US equivalent of chopsticks. My peanut brain cannot
handle all that stuff.

> I don't dive Splashdown any more.

Going for those 30-diver cattleboats, are you? Easier to meet chicks
there, though, I reckon.... my biggest complaint about diving with you
and Lee those years back was that neither of you is a hot,
large-breasted young lady... atleast, neither of you were back then.

V.

mike gray wrote:
> No. I can figger out in my head that it's 29.4 psi every 66
> feet, but what the hell is it at 2 bar?

Some comedian was going on about how single-minded the Chinese must be.
His argument was that they *had* seen shovels and pitchforks and so,
despite having realized the potential for a more effective eating
utensil, the fact that they stuck with chopsticks implied a certain
fixednes of purpose.

The Chinese, OTOH, claim that learning to use chopsticks as a child
helps develop not only physical dexterity but develops the brain
(probably through better motor skill development).

This is the scuba/US equivalent of chopsticks. My peanut brain cannot
handle all that stuff.

> I don't dive Splashdown any more.

Going for those 30-diver cattleboats, are you? Easier to meet chicks
there, though, I reckon.... my biggest complaint about diving with you
and Lee those years back was that neither of you is a hot,
large-breasted young lady... atleast, neither of you were back then.

V.