100m dive bailout

Pierre Farrugia

Hello all,

Till now my diving had been in the region of 60m to 80m range. For bailout I always managed with a pair on 7 liters, a trimix mix and deco mix. Now we are planning for a 100m dive, which will be with max bottom time of 10min, so more a bounce dive sort off. Was playing with some profiles and seems that at least one needs 3 mixes, deep bailout, travel and deco mix. What you guys are you using as bailout mixes for these kind of dives? For deep bailout do you use a best mix, or use same as CCR, which could be even used as diluent?

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Pierre Farrugia

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CCR900

Try using the Ali 11ltrs, slightly bigger than the 7ltrs but the 11ltrs sit better in the water anyway.

You mentioned travel mix, are you just talking about your travel back up? I assume you are not using a travel mix on the way down being CCR and all?? Think about taking just 2 tanks and setting your PO2 on your bailout bottom mix to 1.6 so your FO2 in the mix is as high as possible for the ride up.

Rgds

Fil

Richard Lundgren

Hi

When it comes to CCR and bailout, how do you calculate the size of reserve/bailout gas needed to get the job done?

Do you carry reserve/bailout gas for your personal need or for two divers?

Take the 10 min @ 100 m dive as an example.

Also, I ask this out of curiosity and to get a better understanding on how CCR divers in general plan for this. No political stuff.

Thank you
Richard Lundgren

schford

For me I carry enough Gas for myself upto 3 stage's worth. Upto One bottom mix, one travel mix and one very high eg 80%+ O2.

If the dive is gnarly enough that the above doesnt cover the deco then I go with a team bailout strategy.

Bailout is such an individual thing.....Truth be told I would much prefer a BOB....

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CCR900

I can only speak for myself but these are few points I will consider:

• Depth
• Time
• RMV (mine is cr*p)
• Use of 100% of gas available in bailout, no reserve
• Enough for 1.5 O/C bailouts from bottom shared between 2 divers
• Drop tanks available if yellow SMB deployed
• O2 on board

Rgds

Fil

Johnny Christensen

My personal beliefs :

I carry enough to get myself out of the water plus a small reserve. That is based on that there has to be several things going wrong, before going completly open circuit all the way up.

If the loop has gone bad from CO2. Get off loop, take OC sanity breath untill you are in good shape again.
Flush the loop while you are OC.
Return to loop, if there is the slightest rise in your loop CO2 content, start SCR while you get your butt up to deco depths. If that is not sufficient, go completly OC via BOV.
If at that time, my buddy should have a problem that requires him to get some gas from me. I can help him, but only in limited quantities.
If he needs gas from me, while I'm only in SCR bailout. Then the amount of gas for him is of course bigger ( by the factor of whitch I'm recirculating my gas in SCR)

If I should carry enough OC gas to get myself AND a buddy out of the water on OC all the way. The size of the tanks I need to carry, would be increasing the drag and equipment load, thereby making it more likely to run into a problem.

Yes it would be nice and so much more safer / comforting to have unlimited OC gas supply for every man underwater. But there is a limit to how much I will be willing to carry on my person.

Regards
Johnny

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Richard Lundgren

Is this really true? Wouldn't a simple leaking loop force you to go OC? I was under the impression that virtually every system are quite prone to have a single failure point. I don't know if this is true but more interesting is if most CCR divers rely on the fact that the might recover from Rebreather malfunction and thus reducing the bailout gas?

Ok, but you base your bailout on OC consumption right?

Agree that you would increase the task loading if not used to it but the problem would different in nature from not having enough gas.

Agree that in some situations it would be almoast imopssible to carry this gas thus having to depend more on a strong surface suport.

Take care
Richard Lundgren

Richard Lundgren

10-4. So you carry 1.5 times the actual bottom gas needed to ascend to deco for 1 diver (can be shared with team diver). Same Principe for deeper deco gases? On the shallow stops you rely on the surface suport.

Thanks for the info
Richard Lundgren

decoweenie

Richard,

It is not different than a twinset diver if he is diving 1/2 + 50 bar (as an example). No one/system AKAIK could individually carry adequate bail-out for 2 divers on ocean dives per diver.

So, in short, for ocean dives, each diver should carry enough OC bail-out gas to surface safely from max depth + max BT for himself. If his unit AND his buddy's unit flood at the same time, there is only enough gas for one person to surface safely without surface support (from each diver).

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Mark Chase

Each diver should carry his own requirement in gas. Personally i prefer to match gas with my dive buddy so there is at least the potential for reserve gas if we ascend together.

Some dives will be carried out using team bailout. This will involve the two divers carrying enough gas to get one diver safely to the surface. Obviously this relies on only one CCR breaking down at any one time.

I don't like team bailout because buddies are unreliable. I lernt this the hard way.

There is no need for each diver to carry double gas and in a lot of CCR diving it would not be possible.

ATB

Mark Chase

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