NDL diving with onboard DIL-OUT? Smaller than 40/50's

[211ratsbud]

I have heard there may be some changes or new philosophy reaching the recreational rebreather world.

What I heard suggested that 3l x 2 will be manifolded and used as dil/bail.

has anyone else set up a onboard bailout rig using something smaller than 40/50's?

i think the min gas qty of 2 x 3l sounds questionable, but for boat/wreck diving with a mooring, or shore diving, perhaps it can work.

even 30's manifolded wouldnt be too bad.

thoughts?

 

[Tassi Devil Diver]

For years I have been diving my rEvo with on board 3L dil as bailout for NDL open water dives to a max depth of 20m. I really enjoy jumping with that configuration going on long shallow dives.

 

[slimshady]

Intersting, isn't two 3L about the same as a 40? Chest mount with a slung 40.

 

[PEDiver]

Just going to ask the obvious question: why?

Not trying to be facetious either - I guess I just don't understand the mindset around "what's the minimum amount of gas I can bring on a given dive and still make it out alive?"

Is it to streamline the diver? Is it to make rebreather diving more palatable for recreational divers who are accustomed to only one tank?

Maybe I am approaching it too much from a technical diving perspective - but even on a "recreational" NDL dive, I like to have plenty of gas to get me to safety, to solve problems, to help a buddy, etc.. I just don't see the practicality of only utilizing a couple 3L bottles as bailout and I can foresee divers getting into trouble using that setup.

 

[mr_v]

I am with @PEDiver. I never understood the "let's bring the minimum gas we can." Also, I am probably one of the few folks here who has a 72AL bailout as a standard. rEvo + 72AL on the left is my NDL rec config. Why? You know what NDL dives are good for? Drills. If I am on a rec dive, you bet I'll practice running in SCR mode, performing a bailout ascend, and other emergency drills. Yes, that's on every rec dive.

 

[justinthedeeps]

Are you doing much shore diving? I find it nice to walk my bailouts to/from shore separately.

Totally possible to connect your BOV to your onboard 3 litre diluent cylinder(s) via extra LP hose from the reg and a reachable quick disconnect (QC6). Immediate sanity/panic breaths on safe gas. But only minutes worth.

At 40 litres per minute 'panic SAC', on a ~20 metre deep recreational dive, you will breathe half of a single onboard 3L cylinder in ~2.5 minutes [3L * 100bar / 40 barL/min / 3atm/1atm]. If you're relaxed (≤20L/min), ~5 minutes. 40, 1.5 minutes.

So you're taking some OC breaths while you find your offboard bailout regulator (on an S40 or larger). With no BOV, you are holding your breath or breathing a compromised loop in the meantime. Fine for practice drills .... ....

You could also rig the corresponding QC6 connector onto the offboard bailout, allowing you to pre-plug to it, and/or switch the BOV to it rather than deploying a regulator. Just clip on the S40 or S80 as a stage.

I would do this instead of trying to manifold things, unless you are going deep and running out of places to put other cylinders.

The exception is big strong-backed people, and/or those who just want to pack all their deepest bailout onto their back and aren't doing a lot of shore diving.

 

[flymolo]

I have heard there may be some changes or new philosophy reaching the recreational rebreather world.

What I heard suggested that 3l x 2 will be manifolded and used as dil/bail.

has anyone else set up a onboard bailout rig using something smaller than 40/50's?

i think the min gas qty of 2 x 3l sounds questionable, but for boat/wreck diving with a mooring, or shore diving, perhaps it can work.

even 30's manifolded wouldnt be too bad.

thoughts?

I've noticed a big difference in the total weight of my rig when using AL40s instead of LP50s for the backmounted BO cylinders. Since they are similar in length they don't seem to alter the way the rig dives. The only possible issue is that you may be light if you are wearing heavy undergarments and need to bail out and breathe the gas down.

 

[Whitrzac]

I use to do this when I had a BOV. Now I just take along an al40 on anything deeper than 20ft.

Tech divers tend to forget that the best option for an issue on a NDL dive is to just surface and you only need a few breaths to get there.

 

[rjack321]

I have heard there may be some changes or new philosophy reaching the recreational rebreather world.

What I heard suggested that 3l x 2 will be manifolded and used as dil/bail.

has anyone else set up a onboard bailout rig using something smaller than 40/50's?

i think the min gas qty of 2 x 3l sounds questionable, but for boat/wreck diving with a mooring, or shore diving, perhaps it can work.

even 30's manifolded wouldnt be too bad.

And the oxygen tank goes exactly where?

thoughts?

That diver's have too much time on their hands to eff with stuff despite zero rationale reason or objective

 

[Cio]

Why 2 x 3L, for rec? 1 x 3L is fine and accounts for any single failure.