stage tanks and OOA procedure

[Soggy]

I have no idea how DIR divers would have done that but that was the solution we came up with given the alternatives we had at the time.

Sounds reasonable to me. In this case, his gas was not lost, it was just annoying. There are very few cases where a deco gas would be completely unusable.

 

[limeyx]

Okay but what's the DIR answer to the question of what to do if one guy loses his deco gas, but the other guy still has his - and suppose he only needs 75% of it? And what if you have a three man team and the third guy has another 25% extra of deco gas?

I assume onfloat has some GUE tech training since he answered, but I believe Monkseal and limeyx are tech 1 too, and they seem to prefer a different solution, so which one is DIR? Or are you just taught to go with team preference in DIR tech classes?

I do have tech1, and there are definitely multiple ways to handle this situation.

The simple way is to double the deco time and have one person deco entirely on back gas, the other uses their deco bottle until it is empty and then switches to back gas.

This has the advantage of being "simple" (no switching of regs around) so could be good if conditions are poor, making it hard to switch around or one person remains panicked.

However, sharing the bottle at alternate stops gets you out of the water faster, and gives both divers the benefit of the deco gas. Of course, a third diver can also be used to donate unused deco gas, so in a 3, you have more options.

GUE does not really teach one "Holy" way for deco (and standard and procedures of course do change slightly over time, so each class teaches what is the current understood practice)

The original post seemed to be what if a diver lost backgas and all deco gas. The answer to that is mostly that "it depends" (in my opinion).

Generally you would plan for a loss of either all backgas or a deco bottle and still come out with a clean deco. Any more than that and you are more into the compromise situation.

 

[nadwidny]

Okay but what's the DIR answer to the question of what to do if one guy loses his deco gas, but the other guy still has his - and suppose he only needs 75% of it? And what if you have a three man team and the third guy has another 25% extra of deco gas?

The real DIR answer is that the safety diver gives the OOG diver the gas he needs.

 

[Soggy]

The real DIR answer is that the safety diver gives the OOG diver the gas he needs.

Do you really bring a safety diver along on any dive that requires decompression? I mean, a single bottle deco dive to 150-160 certainly is a manageable failure as is a "shallow" 2 bottle dive.

 

[*Floater*]

thanks for the answers.

 

[ScubaMilo]

Okay but what's the DIR answer to the question of what to do if one guy loses his deco gas, but the other guy still has his - and suppose he only needs 75% of it? And what if you have a three man team and the third guy has another 25% extra of deco gas?

I assume onfloat has some GUE tech training since he answered, but I believe Monkseal and limeyx are tech 1 too, and they seem to prefer a different solution, so which one is DIR? Or are you just taught to go with team preference in DIR tech classes?

Limey-x and mokseal are both stating about the same procedure with minor mod's
due to divers thinking.
The DIR way would be the way they are reporting
GUE would have the divers think!!!
Milo

 

[limeyx]

Do you really bring a safety diver along on any dive that requires decompression? I mean, a single bottle deco dive to 150-160 certainly is a manageable failure as is a "shallow" 2 bottle dive.

For tech1, generally there are not going to be any safety divers.
From what I have seen, generally on a tech2 dive, it is greatly preferred that say a tech1 team gets in the water staggered after the T2 guys, timed to meet them at 70 feet on the way down (for the t1 guys).

That way if there is a problem, there is help at hand. For T2 dives, you are really talking about a very good chance of dying if you have to directly ascend to the surface from my understanding.

Even if you have a safety diver scheduled, you still generally need to plan to have all your gases for a normal dive and reasonable contingency plans because you can always drift away from the safety divers, or get stuck on the bottom or in a wreck etc.

 

[Soggy]

My point to Brian Nadwidny was that I can't imagine requiring safety divers for most dives above say, 200' or so where gas related issues are very manageable. Obviously it becomes very difficult to carry all your own gas along with contingency gas on dives exceeding 250' or so and support divers become a necessity, especially in ocean diving, simply to offload gear from you and monitor you during the lengthy decompressions.

I was also curious at what level he brings support divers along.

For tech1, generally there are not going to be any safety divers.
From what I have seen, generally on a tech2 dive, it is greatly preferred that say a tech1 team gets in the water staggered after the T2 guys, timed to meet them at 70 feet on the way down (for the t1 guys).

That way if there is a problem, there is help at hand. For T2 dives, you are really talking about a very good chance of dying if you have to directly ascend to the surface from my understanding.

Even if you have a safety diver scheduled, you still generally need to plan to have all your gases for a normal dive and reasonable contingency plans because you can always drift away from the safety divers, or get stuck on the bottom or in a wreck etc.

 

[limeyx]

My point to Brian Nadwidny was that I can't imagine requiring safety divers for most dives above say, 200' or so where gas related issues are very manageable. Obviously it becomes very difficult to carry all your own gas along with contingency gas on dives exceeding 250' or so and support divers become a necessity, especially in ocean diving, simply to offload gear from you and monitor you during the lengthy decompressions.

I was also curious at what level he brings support divers along.

Yes, I think we are agreeing, but at tech2 you most definitely (from my understanding) need to carry enough gases to handle an OOA on back gas, and a certain number of lost/malfunctioning deco bottles.

(Always remembering that in the absolute worst case you can swap regs from one tank to another U/W if you have to)

 

[Soggy]

Yes, I think we are agreeing, but at tech2 you most definitely (from my understanding) need to carry enough gases to handle an OOA on back gas, and a certain number of lost/malfunctioning deco bottles.

(Always remembering that in the absolute worst case you can swap regs from one tank to another U/W if you have to)

Yes, we are agreeing. In Tech 2 they teach bottom stage usage as well as 2 deco gases (my regular buddy just went through Tech 2). Obviously, the bottom stage only becomes necessary when you don't have enough gas to maintain rock bottom on back gas. For an ocean dive, barring something pretty extreme (nearing 300'+ where support divers become a no-brainer), I cannot imagine needing much more than an 80 of bottom gas, an 80 of 50%, and a 40 of O2 in addition to your back gas.