deco buddy

[Soggy]

How long would you extend the deco for intermittent backgas switches?. Would you treat it like air breaks?

It depends on the gasses you are breathing. With certain standard gasses, like 50% and 21/35, the deco for 50% is basically half that of the 21/35 deco. So, if you run out of your 50% at 20 ft, you would just double your remaining deco. If you are living in a world where your VR3 runs your dive, I have no idea what the 'proper' procedure would be.

 

[JeffG]

I was a casual observer of this scenario recently. I was part of a different team doing a completely different dive.
The extended deco was the result of the diver not being able to make gas switches on his VR3 so he did the deco for backgas.

He had the gas, but couldn't do it on his computer?

How long would you extend the deco for intermittent backgas switches?. Would you treat it like air breaks?

I wouldn't treat it like air breaks. I would start off as calculating it as being on BG and nibble away at that number depending on what gas (50 or 100) that I used and if in doubt...do it all as if it was BG.

 

[JeffG]

So, if you run out of your 50% at 20 ft, you would just double your remaining deco.

(Just don't mention Ratio Deco though )

 

[Soggy]

(Just don't mention Ratio Deco though )

Sssshh....I was hoping if we didn't give it a name, they'd miss that.

 

[JeffG]

Sssshh....I was hoping if we didn't give it a name, they'd miss that.

Oops...My bad

 

[Diver0001]

The extended deco was the result of the diver not being able to make gas switches on his VR3 so he did the deco for backgas.

You mean he was riding his computer on a deco dive.....

R..

 

[MSilvia]

Sounds that way.

 

[jtivat]

First this person should not be doing deco dives if there gas planning is this bad. And B they should not be doing deco dive's if they are solely relying on a computer to figure there deco for them.

 

[Hyper-limits]

So I guess the lesson here, is always have back up plan on a slate or wet notes.
Still I would have switch to my deco gas, just to be on the safe side and because the dive was in our cold water I doubt that his run time was longer than 70 minutes making the chance of a CNS hit very unlikely.
I would stay in the water with my buddy but he has to buy me lunch somewhere expensive.

 

[matt_unique]

First of all, if your buddy runs out of deco gas (and has to switch to a back gas deco contingency), and you continue your deco with your planned gas, you will not be at the same depths at the same time. You would not be able to hand off your deco gas unless you descended back down to his deco level. You do not want to be doing that.....

I would make sure a buddy joining me on a deco dive is properly trained and properly equipped to handle this textbook contingency. He goes to switch to his deco gas, he has no gas for whatever reason, he then reads a few lines down on his slates and executes deco on back gas. I verify he is all set, wave by-by, then ascend to my next deco stop. I would finish my dive as planned but remain in the water, on the surface, keeping an eye on him.

One more thing - if I were diving with the VR3 - I would still carry my two slates with the same deco plans. I personally use just slates with profiles generated from V-Planner for deco diving.

--Matt