sidemount solo, how low is safe

[flots am]

I dive Side mount and some times, on a day where the vis is above average and i'm on EAN 40 i like to stay down as long as possible, who doesn't. the question is just how low would you guys consider safe.

How much gas do you need to get back to the surface safely, from any point in the dive, including handling any deco obligation and any possible entanglements, if you lose one of your tanks?

Once you have this number, you'll know.

Sorry for the non-answer, but it's completely irrelevant how much gas anybody else needs. What matters is what you need.

For a shallow no-deco dive, the answer might be "none." For a deeper/longer dive with potential deco or overhead, the answer might be "You need bigger tanks"

 

[Phil_C]

:I have multiple dive's there where i have pushed the limit down to 30bar in each tank ( thats still more tank 50/bar together) and feel comfortable, but the other day i had a talk with one of my dive mentors and we talked about complacency and how as we dive more and more we start to feel more and more comfortable pushing limits and how its good to sometimes see if we're pushing them too far

This comment, your mindset that you have 50 bar in total, is exactly why I would actually throw my hat in the ring and say that you are pushing the limits too closely. I echo very strongly what others have said about gauges reading way off at low pressures - I haven't personally checked on high pressures - I might now - but I have certainly had tanks start to breath hard when the gauge said they had 20-30 bar left so I should have been ok.

So lets assume you are at the edge of that old incident pit - you cannot access all of your air because you have a reg failure/freeflow etc. unlike manifolded doubles you cannot isolate one regulator and still have your 60 bar across both tanks. In side mount IF a regulator free flows - you have to turn it off, so you have lost half of your redundant gas, IF the gauge on your remaining tank is not accurate you could easily NOT have 30 bar left to play with.

OK - you can do a CESA and get to the surface without air, so you won't drown, but as you are pushing your dive times to the max - you are also pushing your chances of DCS if you don't do a safety stop and ascend properly.

So 30 bar in each tank might not drown you if things go belly up, but it might earn you a trip to the chamber.

Based on that I would say 30 bar each is too low and is not a defensible gas management plan. - Phil

 

[MXGratefulDiver]

Wrong question ... asking how low you can "safely" push your tanks for solo diving indicates a mentality which is anathema to solo diving.

Personally, I'm far more conservative in terms of minimum gas on solo dives than I am when diving with a buddy ... if I lose a tank for any reason, I want to make damn sure there's plenty in the other tank to get me back to the surface.

If you're concerned about bottom time to the point where you have to cut your margins that thin, you need bigger tanks ...

... Bob (Grateful Diver)

 

[Bob DBF]

If you want more bottom time, bring more tanks. As a solo diver, your only friend is how much gas you have left. I always carry one more tank to the dive site than the dives I plan in case I find something interesting, I can go back rather than take a chance pushing my gas.

I've been known to run my gas down a lot on a benign 15' shore dive, but with my tank empty and no air in my wing I'm positively buoyant so I just kick into the beach. The more variables the more air I keep in reserve.



Bob
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I may be old, but I'm not dead yet.

 

[Wannabedivebum]

Im by no means an expert diver, but that little gas in each tank seems, excuse my language, stupid. As others have said gauges are more of a guide than a for sure dead on thing. Ive had a gauge tell me 400psi, when the tank was empty. Thankfully on dry land. I dive with thirds, for any and all dives. If you require more bottom time, breathe less, or bring more gas.

 

[gekodivebali]

Your initial post clearly shows you do not master the skills necessary for solo diving. You should refrain from this activity until you retrain.
What is your SAC?
How do you plan for your gas (rule of thirds or more conservative?
What are your procedures for contingencies (entanglement, another diver in an OOA situation, etc)?
Do you carry full redundancy?