Deco Gases

[boomx5]

This is not the dir forum. So I was not assuming that. I dont know how much flexibility his dive buddies give him. What you choose always depends on your buddies. It is always best if you can all agree on the same mixes.

My mistake...I thought you knew.

 

[triton94949]

My mistake...I thought you knew.

I knew that this is not the dir forum.

Are you saying that you think Holger was trolling? Maybe he is having doubts about the mixes he has been required to use, and truly is sincere about seeking validation? Who knows?

A good troll can usually start up a conversation, however it often ends with bad feelings when the results prove awkward to the doctrine being trolled.

More to the salient point, TMX 50/25 has its advantages and disadvantages. We have discussed most of them here.

 

[jonnythan]

I knew that this is not the dir forum.

Are you saying that you think Holger was trolling? Maybe he is having doubts about the mixes he has been required to use, and truly is sincere about seeking validation? Who knows?

A good troll can usually start up a conversation, however it often ends with bad feelings when the results prove awkward to the doctrine being trolled.

More to the salient point, TMX 50/25 has its advantages and disadvantages. We have discussed most of them here.

I believe boom was saying that he believed that you knew holger used standard GUE gas mixes. I also didn't see Holger expressing any doubts about what he does or what he knows.

The absolute last thing he was doing was trolling.

 

[boomx5]

I believe boom was saying that he believed that you knew holger used standard GUE gas mixes. I also didn't see Holger expressing any doubts about what he does or what he knows.

The absolute last thing he was doing was trolling.

Yes...that's what I was saying. I'll guarantee he wasn't having second thoughts or trolling, I just thought Triton knew where Holger was coming from that's all.

 

[triton94949]

TMX 50/25 has its advantages and disadvantages. We have discussed most of them here.

I am surprised that Doc Deco never commented.

 

[HolgerS]

Fine discussion. No, I don´t have any doubt about what I am doing. Otherwise I would be extremely xxx
Yes, I am a GUE trained person. However, the deco on the fly rules I am using are my individual work. A friend of mine has V-Planner (from this incredible Ross), so I checked my rules against that. You see, Triton, we are all very close. (I personally don´t have any personal computer, just a business one with strict user rules).

My dive buddies are all DIR minded people, so we dive with same gases and deco rules. The disadvantages you are concerned about are not existing within our team (this is the DIR advantage )

Wish you all the best.

@ Ross:
In my first posting I gave 3 reasons (not scientifically written) for He in deco gases. You as the expert in this discussion, can you please tell us the comprehensive reasons for He in deco gases - mirrored your personal view?
This is the real interesting part of this discussion for me.

Thanks

Holger

 

[Dr Deco]

Hello readers:

Sorry that I did not reply to this long thread. I was in the hospital with surgery for the repair of a hernia. I am back today for a short time. :doctor:

Helium

Regrettably, I have worked primarily with altitude decompression for the last fifteen years. On a professional basis, I do not have any experience with air and helium switches and can not lend anything to the very-applied discussion.

Post Script

I do wish to say, however, that if gas switches in decompression procedures have been tested, then they can be added to the models. It is not the models that are giving the answer – it is the dives from which the models were derived. I am not aware of any radical deco procedures that have been PREDICTED by these models.

1. I have noticed for some time that many divers believe that the models - whatever they might be - are scientifically very valid. All models require an enormous amount of real data to allow certain “constants” to be fitted.

2. There is currently no way to make a decompression model based on first principles. All decompression models require an enormous input of diving data. The analysis requires very powerful computers because of the amount of data.

3. The RGBM, and the VPM, are not the only models employing two-phase dynamics. They are the ones known to recreational divers. These models were not the first, either. While a lot is said about “revolution,” much is promotional [not that this is bad].

4. The concepts underlying these models are not sufficient to develop efficient tables for multiple dives. The dives are too conservative for the surface intervals. Nuclei resolution times are apparently too short. In all models, variation in stress-assisted nucleation is totally absent. :bomb:


5. None of the models is of value for much of what is done by NASA because some of the underlying principles are incorrect. For NASA work, these deficiencies are very important and are not nit-picking.

Dr Deco :doctor:

 

[triton94949]

Hello readers:

Sorry that I did not reply to this long thread. I was in the hospital with surgery for the repair of a hernia. I am back today for a short time. :doctor:

Helium

Regrettably, I have worked primarily with altitude decompression for the last fifteen years. On a professional basis, I do not have any experience with air and helium switches and can not lend anything to the very-applied discussion.

Post Script

I do wish to say, however, that if gas switches in decompression procedures have been tested, then they can be added to the models. It is not the models that are giving the answer – it is the dives from which the models were derived. I am not aware of any radical deco procedures that have been PREDICTED by these models.

1. I have noticed for some time that many divers believe that the models - whatever they might be - are scientifically very valid. All models require an enormous amount of real data to allow certain “constants” to be fitted.

2. There is currently no way to make a decompression model based on first principles. All decompression models require an enormous input of diving data. The analysis requires very powerful computers because of the amount of data.

3. The RGBM, and the VPM, are not the only models employing two-phase dynamics. They are the ones known to recreational divers. These models were not the first, either. While a lot is said about “revolution,” much is promotional [not that this is bad].

4. The concepts underlying these models are not sufficient to develop efficient tables for multiple dives. The dives are too conservative for the surface intervals. Nuclei resolution times are apparently too short. In all models, variation in stress-assisted nucleation is totally absent...

Thanks DocD.

You are of course correct, that no deco model is perfect. The way that I and most others take this into account is by working up to new profiles very gradually. We start out relatively shallow (150 fsw) with relatively short bottom times (15 mins), and then we very gradually work our way deeper and longer, from there. Thus the deco models become our framework for our own anecdotal dive profiles and surface intervals. That also takes into account individual physiological characteristics as well.

I do not vew V-Planner as scientifically perfect.

I do view it as the best tool available to do the mathematics involved in planning multiple gasses and multiple dives. Ultimately, individual application, gradually and conservatively applied, is the first principle of necessity.

Even from dive season to dive season, I tend to start each season with short (15 to 20 min) shallow (150 to 175) dives, to get back into the swing of things for the new diving year. That goes hand in hand year round with jogging and staying in shape and avoiding a lot of pizza and beer.

Hope you are feeling better. Always good to hear from you.

 

[wgasa]

I want to thank everyone who responed with replys,however it was not my intention to start a riot and need a moderator to step in to cool things off.I do think this is a topic that should be addressed further and possibly with some input from people that are actually doing this we can make deco diving safer and more enjoyable {I feel better after using he in my 70 ft bottle}and ride it closer to the surface.Please cut some custom tables that have been done in the real world not by the virtual diver ,post them and change some minds he sale will increase and everyone will be happy and safe.Pm me with any custom tables that you use safly using a TRM 50/?/? Thank you in advance !

 

[triton94949]

I want to thank everyone who responed with replys,however it was not my intention to start a riot and need a moderator to step in to cool things off.I do think this is a topic that should be addressed further and possibly with some input from people that are actually doing this we can make deco diving safer and more enjoyable {I feel better after using he in my 70 ft bottle}and ride it closer to the surface.Please cut some custom tables that have been done in the real world not by the virtual diver ,post them and change some minds he sale will increase and everyone will be happy and safe.Pm me with any custom tables that you use safly using a TRM 50/?/? Thank you in advance !

WGASA if you are diving with TMX 50/25 make sure you have a backup O2 supply of some sort, either a reliable buddy, or a hanging bottle, or a safety diver with an O2 bottle slung for you. If you go the reliable buddy route, then it also makes sense to have two 2nd stages attached to each of your and your buddy's O2 bottle. Hopefully you noticed the disadvantage of TMX 50/25 as well as the benefit.

You did not start a riot. There was simply a disagreement on the definition of what is an "authority in scuba." I believe Ricky was reminding others not to accuse someone of having an ax to grind when there is no evidence of such. No one likes to have their idols criticized, but there is nevertheless a difference between an idol and an authority.