Article in March 2006 issue of Scuba Diving

Thus spake sytech@yahoo.com :

>Dan,
>
>I don't have the article handy but it just "seemed" that maybe the
>author's emphasis on "theroretical" problems might have been overstated
>but I've heard enough here to get the point.

I want to live in Theory. Everything works in Theory.

>
>Towards the end of the article the author advocated that because of all
>these" theoretical" problems that could develop, it's probably not a
>good idea for many people to board the boat with all that heavy gear on
>because the effort required could excerbate any nitrogen retension
>issues that may be at play.

The amount of exertion is minimal. I wouldn't do those 100 pushups
immediately aftwards, but climbing out of the water certainly won't do
anything to most people who were at least a little concious of their
nitrogen loading. And the others are going to get hit one way or
another anyways.

>
>Any thoughts on that?

Be aware of your nitrogen. As a newbie, I'd recommend diving well
within the tables. More room for error when you do screw up, and you
will.

>
>Sy
--
dillon

I didn't climb to the top of the
food chain to become a vegetartian.

Thus spake "Greg Mossman" <mossman@qnet.com> :

>"www.save-money-diving.com via ScubaMonster.com" <u21233@uwe> wrote in
>message news:5f70bc286243d@uwe...
>> sytech@yahoo.com wrote:
>
>> First off .. the most important rule in scuba diving is breathe
>> continuosly and Never hold your breath.
>
>Never? How else do you hold perfectly still to take a photo?
>
>> After your saftey stop ... ascend slowly ... if your going faster then
>> your
>> bubbles ..slow down ... this is not
>> a race ... when you reach the surface ... inflate and relax ... don't
>> stress .
>
>Why not stress? On the surface is where you're most likely to get bitten by
>a shark, run over by a boat, or entangled in a mass of jellies or
>bluebottles.
>

NOT TRUE. I was a good six inches underwater when I ran into the
jelly.
--
dillon

I didn't climb to the top of the
food chain to become a vegetartian.

Theoretically all dive have almost all dives have a degree of nitroigen
supersaturation. With any degree of supersaturation there is always a
risk of bubble nucleation. The dive tables are based on what chance
there is of a large bubble nucleation. Being on safe time does not mean
no bend. However in safe time means the risk of nucleation of a bubble
and the size of the bubble are PROBABLY within an acceptable limit.
One of the biggest risks to bubble nucleation is a fall or bump after
getting out of the water. Think of the bang on the side of a bottle of
coke.
The effect of a bend depends where the bubble forms. In muscle tissue
leave it any decompression risks the bubble moving to a more sensitive
area. Better to be live with a small numb dead spot of muscle than a
cerebal bend.
Bob M

On 30 Apr 2006 13:36:39 -0700, "Bob M" <molab@ww.co.nz> wrote:

>One of the biggest risks to bubble nucleation is a fall or bump after
>getting out of the water. Think of the bang on the side of a bottle of
>coke.

Shit! I never thought of that.
Not much chance of avoiding that on a thirty or more mile return to
port in rough water.

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.

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

Again, I agree with the theoretical risk. I simply dont see people
coming up so fast from their safety stop that they risk barotrauma.
Even from 5m, you'd have to hurtle like mad for this to happen.

So possible - yes.
Likely - no.

For me, this falls in the category of "dont climb onto the boat with
your own tanks" or whatever... the theory is fine, but odds of anyone
staying within their NDLs on a single tank and pretzeling themselves
doing this are probably lower than the odds of being molested by an
amorous dolphin.

I guess my problem is not so much in the concept being pointed out - I
actually make it a point to tell my OW students to come up slowly in
the last 5m (used to be on the old PADI OW exams as well - not in the
newer editions, though) - but in the way it *appears* to have been
presented (keep in mind, I havent read the article - if it is balanced
piece, mea culpa and apologies).

Vandit

Thus spake "VK" <vandit.kalia@gmail.com> :

>
>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"?

Hell, on 6th Street here in Austin it seems like there's a bar every
10 feet.

>
>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.
--
dillon

I didn't climb to the top of the
food chain to become a vegetarian.

"Benoit T" <invalid@noos.fr> wrote in message
news:44578AA5.85037E1@noos.fr...
> mike gray a écrit :
> >
> > VK wrote:
> > > mike gray wrote:
> > >
> > > 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!
>
> Tell that to the NASA engeeners about Mars Climate Orbiter ...
>
> Benoît, who use Metric system ...

There were lots of other problems on that mission, besides just the units.
IEEE Spectrum had a nice article on it a few years back

Dennis

VK wrote:

>
> Going for those 30-diver cattleboats, are you? Easier to meet chicks
> there, though, I reckon....

Six pack. The Explorer, mostly



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.


This is Boca Raton. I can easily have that fixed.