Minimum Gas & Lost Deco Gas

[Lazlo]

They only have one bottle of deco gas.

DiverA lost all his back gas at the start of the ascent. Diver B started the ascent with just enough gas to get 2 divers to the 21m switch.

Don't get this bit. Diver B should have planned to complete all his stops without a deco bottle (or with 1/3 backgas left over, whichever is greater). Without getting a calculator out, wouldn't that imply rather more gas than "just enough to get 2 divers from 45m to 21m?

[Leg Of Salmon]

Maybe I'm getting confused but my understanding of Min Gas is that it gets you and your buddy to the surface? Or have I got it wrong.

As far as I know it gets you to the next gas source. One of "them" will fill us in I am sure .

[SoggyFox]

Maybe I'm getting confused but my understanding of Min Gas is that it gets you and your buddy to the surface? Or have I got it wrong.

i think its supposed to get you to the next available gas, ie your deco bottle.

[nickb]

Why do they have no back gas?

Diver B's back gas should be enough to get both of them to the surface so one dive goes on breathing the gack gas. The other decos out. Once one has deco'd out they swap gas and the other diver decos out

'Cos minimum gas gets them to the switch depth not the surface.

In all likelihood there will still be backgas available but them's the minimum deco rules so Leg's asking what the solution is.

[Mal Bridgeman]

Why do they have no back gas?

Diver B's back gas should be enough to get both of them to the surface so one dive goes on breathing the gack gas. The other decos out. Once one has deco'd out they swap gas and the other diver decos out

Depends, Minimum Gas should be enough gas to get two divers to the *next* gas source. which can be 50% at the 21M stop. In reality it's unlikely to be so tight since MG is calculated conservatively.... and they had left the bottom before the catastrophic and instant gas loss, so the one minute of bottom pfaff is removed.

In a set of doubles I cannot see how the catastrophic and instantaneous gas loss could occur either.

But this is the internet, not reality

Mal

[Scuttler]

As far as I know it gets you to the next gas source.

My mistake...you're right

[SoggyFox]

As far as I know it gets you to the next gas source. One of "them" will fill us in I am sure .

but this isn't in 'that' forum

[SoggyFox]

In a set of doubles I cannot see how the catastrophic and instantaneous gas loss could occur either.

you said 'doubles'.....take yourself to a dark corner of the interweb and give yourself a talking too.

[nickb]

Why is the deco gas unusable? If it's just a fucked reg both divers have two each on their backs that could be used - unlikely they're all knackered too.

[thermocad]

So they've got one set of backgas and one set of deco gas?

Blow off the deep stops til about 9m, adjust the remaining deco by a suitable "oh f**k" factor and each diver swaps between the remaining deco bottle and remaining back gas. Buddy breathing a deco bottle would probably end in a mess.

For that sort of profile the deco isn't going to be major.

What he said.....