Depth: 95 ft, In Deco, 500 psi, No Buddy

[Steve_C]

I think that this is a good post to show what is possible if you find yourself low on air, near or at deco, and at 100 ft or so. Stay calm, relax, etc is an important message.

For all the posters who criticized DD let me remind them that he used his video as a demonstration of what can be done in a certain situation. DD was not actually in that situation. He had a full pony with him all the time. So he was never really about out of air. At any moment if he needed it, which it turned out he did not, he could switch to the pony.

 

[uncfnp]

The lesson from the video is moniter your NDL and psi. Focusing on a task to the exclusion of situational awareness is not good diving procedure. Experienced divers like DD can get away with this but it should never be considered acceptable dive practice.

 

[redacted]

Great post. But it should be recognised that 18 cu ft at 95 ft is more than enough gas to safely surface, even with a 5+ minute SS or deco stop. When I see divers rushing towards the surface, I assume they are OOA or close to it.

 

[Hawkwood]

The lesson from the video is moniter your NDL and psi. Focusing on a task to the exclusion of situational awareness is not good diving procedure. Experienced divers like DD can get away with this but it should never be considered acceptable dive practice.

Best post so far.

Perhaps consider "did get away with this", rather than "can...".

 

[Storker]

Everyone says, "never let yourself go into deco or never run out of gas", but guess what? It still happens.

...if you don't monitor your gas & NDL, and/or don't include proper gas planning in your dive plan.

IM(NSH)O, there's no excuse for going OOG, or "accidentally" going into deco. If either of those happens, you haven't been planning your dive and diving your plan. I've been a bit low on gas (less than 50 bar at the safety stop) a couple times, but I've never gone OOG. If I ever were, I'd be properly embarrassed. And I'd have a darned good reason to. I have, however,on more than one occasion adjusted my depth and/or cut my dive shorter than planned due to higher gas consumption than anticipated. Because I make sure to monitor my SPG. and my PDC. Even if I'm shooting pictures or hunting.

 

[redacted]

...if you don't monitor your gas & NDL, and/or don't include proper gas planning in your dive plan.

IM(NSH)O, there's no excuse for going OOG, or "accidentally" going into deco. If either of those happens, you haven't been planning your dive and diving your plan. I've been a bit low on gas (less than 50 bar at the safety stop) a couple times, but I've never gone OOG.

I have gone OOG a number of times, but it has always been planned and in a safe environment. I like to test all of my regulator setups so I know of any surprises. Turning the valve off just is not the same.

Mk7s honks at 400 psi then stops delivering breathable gas through the primary at about IP, but the alternate is still OK. My unbalanced piston on my pony starts to give me warnings around 500 psi - plenty of gas for a slow trip from the SS to the surface. Balanced pistons with balanced 2nds sneak up on you with little warning.

 

[jzipfel]

Best post so far.

Perhaps consider "did get away with this", rather than "can...".

I have been holding this post for an hour, and I still think it is worth saying:

If this thread was started by someone very few people knew, had maybe 50 dives, and was lobstering, how many would be saying " good job staying calm" and would instead be saying "why did you purposely stretch the limits of your gas and your NDL??"

I think I understand the purpose of DD's post "stay clam, NDL does not mean shoot to the surface" but I think the intended audience will miss this and instead only see that he was lowish on air (for most rec divers), stayed down to accomplish a task, went into deco, made it to the top.

To put a further exclamation point on it, there has been a semi-active post about ponys. The general consensus appears to be "don't use the pony in your gas planning, use it as a redundant air source. DD implies (intended or not) that he was OK because he had his pony almost (but not quite) implying his pony was part of his primary gas planning and not a redundant or second source IN CASE the stuff hits the fan.

Other then say OH! 500 psi was plenty to get to the surface. Again the pony discussion, many and prob not the poster here, the majority of people say anything less tank 40 CuFt (more than 500 psi in a 109) is the bare minimum.

I just think that this post and the responses is quite contradictory on may levels and does not assist the newish diver. Especially when one steps back and objectively looks at the general conservative bent of safe diving protocols.

OK. I've said my peace. I feel better now.

PS. Please read the first part of my post again. I think I understand the intent of DD's posting but maybe the approach could be better.

 

[redacted]

Other then say OH! 500 psi was plenty to get to the surface. Again the pony discussion, many and prob not the poster here, the majority of people say anything less tank 40 CuFt (more than 500 psi in a 109) is the bare minimum.

I doubt if you will find many who would say a 40 is a bare minimum for a pony. Many will say why not a 30 or a 40. (I do know of at least one dive boat that will not allow a pony larger than a 30.) I suspect the majority will say that a 19 is adequate.

 

[jzipfel]

Maybe I just have this one stuck in my head. You are correct not everyone, but there are some who do

From the most recent Pony Bottle discussion
Pony bottle

@jzipfel it depends on how much reserve you have. I believe in Rock Bottom calculations mostly and if I do the calculation at 100ft with a sac of 1, I get 20cf needed. I always reserve at least 500psi in my tank for regulator performance. Where I disagree is 1 minute to assess, I prefer at least 3 mins so you can get to the other end of the wreck, or calm a buddy down, or whatever you choose to do. If I were to dive with a pony bottle, I would use that as my source of air, i.e. no octo on my back gas regulator which means I need that to have enough time at the bottom for me to stabilize everything. AL40 is the minimum I would go with for a pony bottle because even following the Dive Nerd calculator, you need 34cf to get up. No problem, an AL40 will suffice and cut it close. That said, if my regulator explodes and I'm on my pony and I have an AL40, but only diving to 100ft where that calculator says I need 20cf, if I'm on that bottle and everything is going fine except my regulator blew up, then I'll do my ascent as normal because my pony bottle will have at least as much gas in it as my backgas tank would have if it didn't blow up so why change your ascent plan? Only time I have a "do not pass go, do not collect $200" moment is if someone thumbs the dive *we always use the turn around sign to start an ascent unless in an emergency*. A failed primary regulator to me is something that immediately causes the dive to end, but if you have ample gas and you go up from 100ft to 60ft and there is something cool at the top of the wreck, I have no issue stopping for a minute or two. That said, I'd be diving doubles on that dive and not have to worry about it, but I have buddies that use pony bottles and that is something you have to discuss and weigh against your personal risk aversion.

 

[northernone]

I appreciate the post now and I find it an appropriate demonstration for a life saving message. I say this since an old diver passed that exact message on to me as a child diving. Panic and you wind up dead. I always appreciate a plan C tool even if I never intend in needing plan B tool after a good plan A.

Just like the forum, have a few extra tools around doesn't hurt the discussion. ; )

And +1 for prevention.

Thanks for sharing.
Cameron