stage tanks and OOA procedure
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MonkSeal
Contributor
We were taught to round up stops at deep part of deco and double shallow stops exchanging deco and back gas. The other version is 1.5 total deco exchanging deco and back gas.onfloat:
Going for double deco on back gas while others decoing at EAN50 doesn't make much sense from team perspective because you're potentialy raising other issues like hypothermia.
limeyx
Guest
onfloat:
I would share the bottle at each stop, 1/2 for me, 1/2 for a buddy and do 1.5x longer stops until the bottle ran out (note: I'm only trained for one deco bottle)
Better to spend less time if you can and get the benefit of the 50% down deeper where the PO2 is higher. The shallower stops on 50% are offgassing you based on a gradient, so decoing on back gas is fine there (can still do 1.5x the stops)
but yes, you could also double the stops (but then the buddy with the not-lost deco bottle is going to have to go to backgas at some point too probably)
limeyx
Guest
*Floater*:
See above, but you can hand off the reg just fine with a 40" hose.
Share it deeper is better to get the benefit of the high PPO2 (no point sharing it at 20 feet)
Why is it in this forum people ask for a DIR answer to a specific problem.
Then upon recieving such answer decide to argue or try to change the answer.
The bottom line seems to be if you don't want to hear the DIR answer then don't ask here.
As for the answer to your original post it has been answered and re-answered by more than a few of us.
So good luck to you and take a GUE class it will then be much clearer.
All these procedures and many others are covered step by step in the classes.
As stated by Limey-x The internet is not a good place to learn to deco dive.
Milo
Then upon recieving such answer decide to argue or try to change the answer.
The bottom line seems to be if you don't want to hear the DIR answer then don't ask here.
As for the answer to your original post it has been answered and re-answered by more than a few of us.
So good luck to you and take a GUE class it will then be much clearer.
All these procedures and many others are covered step by step in the classes.
As stated by Limey-x The internet is not a good place to learn to deco dive.
Milo
*Floater*
Contributor
ScubaMilo:
No one is here "to learn to deco dive" but people are taught different things by different agencies and instructors, and there's no reason not to discuss different approaches on the internet. At least GI3 never had a problem sharing his ideas on deco and emergency responses.
*Floater*:
I'm not so much saying that the question should not be asked or discussed.
But in the DIR forum you will get DIR answers.
These answers may or may not align with what you were taught(depending on the agency you learned from).
So to argue that the long hose would be traped is not a valid arguement if you donate what you breathe(DIR).
So I guess what I'm saying is without first knowing the system, the procedures give you very little help.
Therfore to try to adopt a procedure from a system you have not been trained on is not always a good Idea.
That is what I meant by learning on the internet is no good.
I think discussion is great.
But remember we are in the DIR forum questions and answers should reflect such.
Just my opinion,
Milo
*Floater*
Contributor
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?
mania:
I've actually had this happen. In that case, it was my buddy whose stage bit it. His first stage "blew up" when he turned it on and it bubbled out of just about everything except the 2nd stage.
We had just started our deco (which was reason he turned the stage on). On this particular dive we were diving nitrox (Adv EANx) and we had alternatives.
Our solution was this.
- I had already switched gasses and he was 2nd. When he went to switch we got the jacuzzi.
- I signed OK to him and he gave me "no" and remained on back gas.
- I moved in a little closer and signed if he wanted to share my deco gas.
- He signed "no" and feathered his stage on and off a few times while he experimented with if he could breathe from it or not.
- He signed to me "OK" and then something that I understood that he wanted to "feather" his deco gas until it was finished.
- I signed back to him that I would control depth so he could concentrate. He gave OK back.
- After that he proceeded to feather his stage while I watched depth until we were done with deco. i don't recall how much hang time we had, maybe it was 10 or 12 minutes or so but we finished the deco without further incident and surfaced.
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. Incidentally this happened during my first ever staged decompression dive and as a matter of fact it wasn't until after the dive that I realised that he really had a problem and it wasn't part of an excercise for the course.... LOL
R..
Soggy
Contributor
*Floater*:
First, you don't get into the water needing 75% of your deco gas. You reserve 1/3rd of your deco gas for emergencies, thus never plan on using more than 27 cft in an al40 and 50ish cft in an al80. That way, you can have enough gas to do all your deco x1.5 if a teammate loses his.
The team stays together. If you have a teammate that has lost deco gas, you would extend the time by 1.5x (2 minutes becomes 3 minutes, 3 minutes becomes 5 minutes, 4 minutes becomes 6 mins, etc). You would then do half of the original time (or 1/3rd of the extended time) on your deco gas, then pass the reg off to your buddy where they would do an equal amount of time on the deco gas. 2/3rds of the total extended time will end up being on back gas. That way, everyone has enough (or close to enough) gas and the team can stay together. The most important part, the deep stuff, is done, and if you run out, your can double your remaining stops.
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