Mania(Offline)

OK I have a question concerning OOA procedures with stages.
Let's imagine 2 divers team. Gas switch. First diver switches to stage. shows OK. Now the second diver. switches and -let's imagine - the first stage of the regulator broke down (which is possible). So now two questions:
1. What is OOA procedure? You can't use the bottom gas and the long hose because it would be blocked by the stage hose running on top of the long hose and only half of it would be released.....
2. Both divers planned deco gas properly so there is enough for both of them. But how do you share the deco gas using really short stage tank hose?

I was looking for a detailed procedures of OOA in case of using stage tanks but couldn't find one....

Mania

Alastair(Offline)

Just want to check the scenario - Diver-1 is on their stage. Diver-2 switches but the reg doesn't work because the first stage broke on their stage.

A) Diver-2 can go OOG and diver-1 will donate their stage reg and switch to their backup. Diver-2 is then on a gas supply on a 40" hose - which is not that short, perfectly long enough to share given you'll typically be monitoring each others gas switches closely and will therefore be pretty close. Diver-2 can then work out he has two working regs on his twinset, and use one of them, he's then got time to re-try his stage.

B) Diver-2 notices his deco bottle doesn't work. Theoretically his long hose is still in his other hand so he just swaps back to it. He can then try and fix his stage and try again.

Donating a stage reg is very straightforward - same principle as with the long hose you just hand off the known working reg from your mouth and switch to your backup.

In terms of deco - if you want to share the deco gas then the easiest solution is to increase your stops and split the time. e.g. we each do 1/2 of the stop time using the deco gas and spend the other 1/2 on our backgas.

Cheers
Al

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MonkSeal (Online)

Or he can goes for his backup if long hose is clipped off, sort-out what he has to and then return to long hose (depending if stage is fixable or not).

rjack(Offline)

Is this why the UK folks are using 80s for 50% deco in tech1? And are able to push single deco gas times up into the 40+ minute range?

So with one deco bottle you are sharing at each stop and then adding some percentage to your total time? How much time are you adding and where in the profile do you add it?

(BTW, This is not how we're being taught to plan nor resolve this issue over here in the US. My T1 class wasn't that long ago -1.5 years.)

Ahmed Adly, Marlin Inn DC(Offline)

You should multiply stop times by 1.5, then split the stage time in half between you and your buddy.

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maccajim(Offline)

hiya
In my tech1 training if u have problem with deco gas switch to backgas and double the deco time. If diver who loses deco gas is very stressed hand her/him your bottle and double your own deco on backgas.

Ahmed Adly, Marlin Inn DC(Offline)

AS far as I can tell, these are not standard procedures at all. But the one I mentioned dose work. We have needed it a few times.
The funniest time was a diver who um..... lost her stages And I mean plural as in 2 deco gases went missing that day.

Also, I always make sure I have enough deco gas for just this situation. It is pretty easy actually as long as you are using O2. But as I have been gathering, the tech 1 is not advanced enough yet to qualify a person for multi gas deco.

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It has just dawned on me.... We are all just recycled stardust
Ahmed Adly,
www.deepvoyage.com

Mania(Offline)

To make myslef more understandable...

I'm trying to imagine the situation - which after all is not impossible - that diver 2 lost all his gas. Both - the bottom one and the deco one.
If the dive was properly planned diver 1 has enough gas to get both of them out.
Now what is the procedure?

My point was - the routing of hoses in this case in fact blockes the long hose. So diver 1 has to either handle the stage tank (with deco gas) to diver 2 and switch himslef to the bottom gas. Or has to unroute the long hose (which means talking regulator out, maybe switching to his backup one, then get the long hose from UNDER the stage one, handle the long hose and get back to deco gas). The second situation for a panicked diver that has no gas at all is way too long....
And it's easy of there is only one stage tank. What if we have two or more????

Still no clear procedure. We have clear procedure - step by step for an easy OOG situation but I can't find a step by step procedure for such situation.

Mania

MarkT(Offline)

Sorry, just to restate it as the conditions seem to have changed, you are assuming that diver 2 has had a failure on both his left and right posts on his back gas and also a failure of his deco gas at the point where Diver 1 has already switched to his deco gas?

This is way outside my training but it would seem obvious in this situation for diver 1 to pass the reg from his deco gas to diver 2 and switch onto his own back gas as the first step.

Even with a short hose on the deco gas it would be faster than any other solution. Once both divers have gas again you can move the deco bottle over if needed to reduce the effect of the short hose.

The long hose on diver 1 is now free to be deployed so diver 2 can pass the deco gas back and switch to diver 1's long hose when it is diver 1's turn to complete deco time on the deco gas, or am I missing something obvious?

Ahmed Adly, Marlin Inn DC(Offline)

+1

If a diver was to loose all back gas he would have redundancy with his buddy. If he then went on, to loose all his other stages, he would have redundancy with his buddy as well. And/Or, you have several failure within a team, that is generally sloppy with their gear (they would be a likley team cause no one else would dive with them).

__________________
It has just dawned on me.... We are all just recycled stardust
Ahmed Adly,
www.deepvoyage.com