Question about dbl tank hose config and single SPG

[yceltikci]

Hi, Salute from Turkey.

I have one question that I could not figure it out myself.

In the above config. there is standart DIR hose system is shown. And there is only ONE SPG which is connected to the backup reg.

What if 1st stage of backup reg. breaks and the diver has to turn of that valf and the manifold to save the air on the left tank? (I'm refering the picture so right means backup and left means the primary reg with long hose)

At this moment, the left tank has no connection with SPG and SPG is out of order already. How does the diver know hom much air he/she has left?

Thank you in advance for the answer.

Regards
Yener

 

[TSandM]

You are right. If the diver has to close the left post, he loses pressure information. However, he should know what his pressure was at the time he closed it, and know what his gas consumption is at that depth (or to that point in the cave) so he knows what it will take to exit. It is always possible that enough gas was lost during the problem to get him BELOW the amount required to exit, but that is why an unfixable post failure is a non-negotiable reason to end the dive and begin the exit. Team members need to be aware of the failed post and the possibility that that diver may be low or run out of gas, and therefore the failed post diver is put in the middle position, where he has easy access to either of the other two in the event he goes OOG.

 

[yceltikci]

Thanx... This was approximately what I thought. But remembering DIR is most of the time about redundancy, I was expecting to see a second SPG somewhere around

Rgrds
Yener

 

[LiteHedded]

well at that point you're going to thumb the dive and it doesn't really matter what your pressure is

 

[Rick Inman]

Thanx... This was approximately what I thought. But remembering DIR is most of the time about redundancy, I was expecting to see a second SPG somewhere around

Rgrds
Yener

The spg is the redundancy.

 

[b1gcountry]

But remembering DIR is most of the time about redundancy, I was expecting to see a second SPG somewhere around

Actually, compared to a lot of people's tech setups, DIR configurations eschew redundancy that is not likely to make any difference. Once your right (backup) post goes, you are ending your dive. Even if you had an SPG on the left post, you would still head to the exit/anchorline with your team, and surface without unnecessary delay. If you have planned your gas properly, and didn't lose too much when you lost your post, you should still have enough to surface. If you had an extra SPG, it would give you a nice warm fuzzy, but you would do exactly the same thing.

Tom

 

[rjack321]

Once your right (backup) post goes, you are ending your dive. Even if you had an SPG on the left post, you would still head to the exit/anchorline with your team, and surface without unnecessary delay.

By convention, the posts are described as left and right as worn by the diver, not how they are viewed by the buddy.

 

[b1gcountry]

I know, I was keeping the same terminology as the OP based on his comments.
Tom

 

[rjack321]

I know, I was keeping the same terminology as the OP based on his comments.
Tom

Gotcha. I suppose I should have started there :doh2:

 

[MonkSeal]

Thanx... This was approximately what I thought. But remembering DIR is most of the time about redundancy, I was expecting to see a second SPG somewhere around

Bottom timer (+consumption rate knowledge) 1st one, SPG 2nd