31 replies to this topic

[ScubaDadMiami]

Many decompression algorithms exist out there. The longer and deeper the dive, the less testing there is in the real world to back up the algorithms.

Especially in the past, the ones employed by commercial companies that engaged in things like deep sea diving in the North Sea oil industry were developed to bring the divers as quickly and efficiently back to sea level pressure. These were often proprietary and kept secret because these are commercial companies that are concerned with the bottom line: Less deco time equals less money spent and more profit. If you can bring the deal in for a lower price, you can make more or outbid competitors.

The problem is that necrosis would not show up in former commercial divers until they became older, often years after they ceased commercial deep diving. At times, when these divers were killed by things like auto accidents, the damage could be seen at much younger ages from autopsies. As these issues came to the forefront, the profiles were modified.

There are competing interests between speed and risk when limited supplies of breathing gas or other conditions (changing ocean conditions, weather, etc.) exist. Otherwise, one could ascend from depth at such a slow speed that any risk factors are almost completely eliminated. In reaching this balance, when conducting technical dives, many elect one algorithm or the other but also throw in some fudge factors for added safety margin (additional stops, longer stops, etc.).

[SquattingRadishDM]

I think the pain in the joints is due to pain receptors in the joints. The brain does not have pain receptors --- well, not counting emotional ones.

My point was that due to the relatively small bloodflow to the joints (compared to the brain or other organs) they absorb and release gases slower and hence are more prone to micro-bubble formation.

Is it the the fact that the longer you spend working at P1, (either at D1 or at surface D0), the longer your DCT?

Yes

Is that time debt linear?

No it is exponential

there is a section on saturation decompression in the bove and davis book you ordered (in the chapter on mixed gas diving) that explains things simply. it pretty much says it's a linear relationship. bear in mind that it'd never be perfectly linear (as mathematics would suggest!!) due to the numerous variables provided by the human body.

TF Im confused, what relationship are you talking about? I dont have the books that you and Walter are referring to.

[Walter]

Is it the the fact that the longer you spend working at P1, (either at D1 or at surface D0), the longer your DCT?

Yes

Up until the point the diver is saturated, then the DCT becomes maxed out. Since this was a question about saturation diving, I believe the correct answer is no.

[SquattingRadishDM]

Yeah thats true Walter . Forgot this was Sat diving not a general DCS discussion.

[triggerfish]

radman...
the relationship between time of saturation to dive of decompression. it's what you said, only i twisted it up to make sure i confused people.

sorry.

[domino22]

This is how we did it in the Gulf Of Mexico in the mid 1980's. We dove air to 170ft. After that it was 80% helium 20% O2. Saturation mix and other depths depended on depth, we had our own tables for this. As for deco in Saturation it was 24 hrs to come up from each 100ft. I.E. 400ft took 4 days to come up. Now a days I would have no clue back then I never heard of tri mix!

[Funewgy]

Michael, great questions.

Everyone else, great insight to great questions.

Damn, I am feeling really stupid right now. Am I that dumb? Is everyone else that smart? Or do I just have a ##$% load of learning to do?

Please keep this kind of discussion coming. The funewgy in all of us appreciates this kind of opportunity to learn. Thanks again.

[SquattingRadishDM]

Am I that dumb? Is everyone else that smart? Or do I just have a ##$% load of learning to do?

Dont worry abt it man, you probably have knowledge in areas that no-one else on the board has. Kudos for starting this inlightening thread.

Domino22 I'd like to hear more about your deep procedures, isnt 20% O2 kinda high for a deep mix because of the toxicity? Was the 80%He/20%O2 mix used to saturate ur body with inert gas then u used deeper mixtures when diving?

When u say "it took 24 hrs to come up 100ft" do you mean they brought u straight up to the surface and u went straight into a chamber, back down to depth and then recompressed. Or it literally took 24 hrs to ascend inside ur diving bell, habitat or whatever they use?

[dive_addict]

For deep commercial diving the heilox mix is 90/10.

I took a tour of a local commercial diving training center (DIT in Seattle, WA) back in May. They described generic sat. diving procedures to me. Usually the vessel the divers are using has a multi-roomed chamber. When they divers arive on the vessel they're put in the chamber and taken to the equivilent pressure of the depth they will be working at. They're transported to to the actual depth via a diving bell. The divers can remain at this depth until they're fatigued or get too cold. Then back to the bell and up to the surface, all the while remaining at the same pressure, hence no need for decompression. After possibly weeks of sat. diving their decompression is done in the controlled enviroment of the chamber.

I've seriously considered becoming a commercial diver. When I'm not diving, I build bridges. So much of my experience would cross over to my new career. However, it's not the bone depletion or other maladies that are holding me back, it's the fact that I would have to live with a bunch of other smelly stinky guys on an oil platform or ship for weeks on end.

The pay can be very good. A diver gets a base salary of about $1500-2000 per week. But the real money comes from the depth pay bonus.

0-50 is company water (no depth pay)
50-100 $1 per foot
101-150 $2 per foot
151-200 $3 per foot
201-250 $4 per foot
251-300 $5 per foot

So a 300 foot dive becomes a $750.

[WreckWench]

So thats why you guys go so deep....to get away from the other stinky smelly guys! LOL!!! -ww

[BradfordNC]

So thats why you guys go so deep....to get away from the other stinky smelly guys! LOL!!! -ww

well yeah, when ya go deep, you push past where the other guys have been.



oh wait, your talking about huh?

nevermind

[triggerfish]

I've seriously considered becoming a commercial diver.

The pay can be very good. A diver gets a base salary of about $1500-2000 per week. But the real money comes from the depth pay bonus.

make sure you have really good health insurance and a wheelchair for your future, honey.

mazel tov.

[mvillanueva]

Damn, I am feeling really stupid right now. Am I that dumb? Is everyone else that smart? Or do I just have a ##$% load of learning to do?

Yes.

[WreckWench]

So thats why you guys go so deep....to get away from the other stinky smelly guys!  LOL!!!  -ww

well yeah, when ya go deep, you push past where the other guys have been.



oh wait, your talking about huh?

nevermind

WELL...I WAS talking about diving....

[triggerfish]

Damn, I am feeling really stupid right now.  Am I that dumb?  Is everyone else that smart?  Or do I just have a ##$% load of learning to do? 

Yes.

again with the long answers, mv.....