Exceeding the NDL during recreation diving

[LI-er]

What were your identified risk factors and mitigations?

Not understanding the question.

As I said I carry a redundant gas supply and I have plenty of gas remaining to satisfy my DECO obligations.

 

[Nick_Radov]

The conservatism settings on some dive computers such as Garmins are a bit confusing or mislabeled. Using a lower GF Low % isn't necessarily more conservative. If you exceed the NDL then it will increase the depth of your first deco stop relative to the nominal ZHL-16c algorithm. But more recent research indicates that maybe isn't safer from a DCS standpoint.

Gradient Factors in a Post-Deep Stops World

World-recognized decompression physiologist and cave explorer David Doolette explains the new evidence-based findings on “deep stops,” and shares how and why he sets his own gradient factors. His recommendations may give you pause to stop (shallower).

indepthmag.com

 

[happy-diver]

As I carry an auxilliary bottle due to divers asking crew how is it that guy dives alone when nobody else does

I fill it with 50% and do not go out of my way to go into deco but breathe from it when I choose deco or not

Yeah, if I build it and own it, then I'm going to pump with it boost through it and breathe underwater from it

without paying some dude to show me

How's my fifty year old brand new CCCP 3phase electric lubricated with glycerine O2 booster

 

[tursiops]

You said this; my comments beneath your post indicate my concerns.

I am not tech certified but I do carry a 19 or 30 cf pony bottle, many or even most of my dives are solo.

I often exceed NDL limits and incur anywhere from a 1 to 10 minute DECO obligation, most of which is offgassed before I even get to the required stop depth which is always 10' for a minute or two.

In fact when I dived Truk Lagoon last year, I found that it's commonplace for recreational divers to go into DECO on almost every dive, due to the large steel tanks and depth of the wrecks and the numerous dives per day. The practice is certainly not discouraged by the dive charter we used for a week long liveaboard trip.

Whether you allow yourself to go into DECO or avoid it, and thus shorten virtually every single dive you ever do is completely up to you and your level of risk tolerance. Of course you need to have good gas management. You don't want to be in a situation where you've got a 5 minute DECO obligation but only 500 psi in your only tank.

Sure, dive charters will say "if you go into DECO you're done for the day" but as long as you clear your computer before you surface, they aren't going to know. Unless you're diving with an over zealous intrusive dive guide in which case you might have to dive more conservatively.

There's no PADI police down there.

• You are not tech certified; I assume that also means not tech-trained. You have presumably learned your deco procedures on your own, from reading. Do you know what you don't know?
• You refer to your 19 or 30 pony as a redundant air supply. Yes, for NDL diving, as taught in all solo courses which do NOT teach deco as a solo procedure.
• Good divemasters will usually know if you;ve gone into deco and cleared it before you surface, and will almost certainly know if you did an actual deco stop.
• You refer to an over-zealous dive guide.....so you are ignoring their responsibility for you during a dive.

This post also referred to the above post

Textbook example of normalization of deviance.

And received multiple Bullseyes and Likes.

You responding by saying this, which was actually a useful thing to say, but it ignores the fact that your knowledge and experience gained was on-your-own so possibly if not likely incomplete

Textbook example of gaining knowledge and experience and applying it to enhance the experience.

So I gave you a caveat rather than allowing you to say you had complete knowledge and experience.

Partial knowledge and inadequate experience.

Your response:

Do I know you? Do you know me and my level of knowledge and experience?

Didn't think so

Your posts say volumes about your knowledge and experience. You appear to be an untrained tech diver that assumes you know it all. Steinbil was right:

Textbook example of normalization of deviance.

 

[crofrog]

Not understanding the question.

As I said I carry a redundant gas supply and I have plenty of gas remaining to satisfy my DECO obligations.

When discussing risk tolerance, it's essential to first identify all possible threats that contribute to those risks. Risk tolerance isn't just about deciding what level of risk you’re willing to accept; it’s about systematically recognizing every potential hazard and developing clear mitigation plans. This process helps you fully grasp the scope of what you're dealing with, ensuring that you have accounted for every variable that could impact your safety.

Without a thorough risk assessment, simply having a redundant gas supply might not adequately address all potential scenarios. Identifying risks is the first critical step in understanding and managing your overall risk exposure.

1. Have you identified all potential failures that could occur during a decompression dive with a single cylinder and a small pony bottle? For example, how would you handle a situation where both your primary and pony regulator systems experience issues?
2. In your current setup, how many simultaneous failures can you realistically manage?
3. What’s your plan if you experience a high-stress situation that significantly increases your gas consumption during decompression? How does your current gas supply account for unplanned delays or increased workload?
4. What’s your plan if you’re delayed leaving the bottom dealing with a failure?

 

[LI-er]

You said this; my comments beneath your post indicate my concerns.

• You are not tech certified; I assume that also means not tech-trained. You have presumably learned your deco procedures on your own, from reading. Do you know what you don't know?
• You refer to your 19 or 30 pony as a redundant air supply. Yes, for NDL diving, as taught is all solo courses which do NOT teach deco as a solo procedure.
• Good divemasters will usually know if you;ve gone into deco and cleared it before you surface, and will almost certainly know if you did an actual deco stop.
• You refer to an over-zealous dive guide.....so you are ignoring their responsibility for you during a dive.

Yes I have learned my deco procedures on my own, from reading and from experience. Is there something wrong with that? Does everything have to be taught be a real live person in order for it to be valid?

The question is of course, rhetorical.

You are saying that divers don't do DECO as solo divers? Wow who knew.

Good divemasters won't know if a diver has done a DECO stop if the diver is not under their supervision, which would be the case if they're diving solo. You really need this spelled out?

I referred to an overzealous dive guide, who happened to be below me on the line, I did not dive with this DM and was not under his supervision- as clearly explained in my post that you apparently missed.

 

[LI-er]

When discussing risk tolerance, it's essential to first identify all possible threats that contribute to those risks. Risk tolerance isn't just about deciding what level of risk you’re willing to accept; it’s about systematically recognizing every potential hazard and developing clear mitigation plans. This process helps you fully grasp the scope of what you're dealing with, ensuring that you have accounted for every variable that could impact your safety.

Without a thorough risk assessment, simply having a redundant gas supply might not adequately address all potential scenarios. Identifying risks is the first critical step in understanding and managing your overall risk exposure.

1. Have you identified all potential failures that could occur during a decompression dive with a single cylinder and a small pony bottle? For example, how would you handle a situation where both your primary and pony regulator systems experience issues?
2. In your current setup, how many simultaneous failures can you realistically manage?
3. What’s your plan if you experience a high-stress situation that significantly increases your gas consumption during decompression? How does your current gas supply account for unplanned delays or increased workload?
4. What’s your plan if you’re delayed leaving the bottom dealing with a failure?

We're talking a mild DECO obligation, which is usually cleared on the way up or perhaps would require less than a 5 minute stop at 10'.

In the almost infinitesely small likelihood that both my primary and redundant gas systems failed during that maximum 5 minute stop at 10' leading to an immediate and catastrophic loss of air I would be forced to surface and risk getting bent. What would other tech divers do if diving solo and experiencing an immediate and complete loss of gas in both their main and second cylinders while still having a DECO obligation?

How many simultaneous failures can I realistically manage? What sort of failures other than the immediate and total catastrophic loss of the contents of both cylinders would I possibly be exposed to?

I don't get stressed to the point that I would increase my gas consumption to the point that I would use up a full 19 or 30cf pony bottle before meeting a 5 minute or less DECO obligation.

What sort of failure would delay me leaving the bottom? And any such failure would have to be reckoned with during literally ANY dive, whether the diver has 1 cylinder and no DECO obligation or two tanks with a short DECO obligation.

 

[LI-er]

And received multiple Bullseyes and Likes.

Wow! 5 people liked the post! Go have a cookie.

Do you think the earth is flat? A lot of people believe it is.

 

[tursiops]

Yes I have learned my deco procedures on my own, from reading and from experience. Is there something wrong with that? Does everything have to be taught be a real live person in order for it to be valid?

The question is of course, rhetorical.

What you've learned may be completely valid, depending on the source. There is a lot of quite incorrect info out there that should be ignored. . It is what you have NOT learned, or is incorrect, that may kill you.

You are saying that divers don't do DECO as solo divers? Wow who knew.

No, I did not say that. I said that Solo courses only teach NDL diving.

Good divemasters won't know if a diver has done a DECO stop if the diver is not under their supervision, which would be the case if they're diving solo. You really need this spelled out?

I referred to an overzealous dive guide, who happened to be below me on the line, I did not dive with this DM and was not under his supervision- as clearly explained in my post that you apparently missed.

I guess I do not understand. You are on the same deco line...but not under that DM's supervision? Was he a private DM for someone and not the DM for the group?

 

[LI-er]

I guess I do not understand. You are on the same deco line...but not under that DM's supervision? Was he a private DM for someone and not the DM for the group?

There were a dozen or so divers on the Duane, some of which were a group led by a DM. I was diving solo.

The DM happened to be below me on the mooring line at the safety stop (not a DECO stop or DECO line) and glanced at my pressure gauge.

I said that Solo courses only teach NDL diving.

Yes, of course that's true. Not sure why you mentioned it in the first place?