Is Deep Air / Light Deco (bounce?) Discussible on ScubaBoard?

[DevonDiver]

Actually they DO.... provide fly by wire or whatever the hell that means. That is one of the dangers of this type of diving. It is very simple.. follow the computer, exactly like you do when doing a recreational no-deco dive..It is misleading to say that modern dive computers can not be used to execute deco dives (especially short ones at moderate depths). If that were not so, I most certainly would be dead.

And what will that computer tell you to do if you didn't have enough air to complete the deco? Or... or...or... or....

What I meant was... the computer will tell you the depths to stop at, the time to wait... but it cannot tell you how to achieve that. It won't provide any variables, if you need variables. It won't consider or cater for, any contingencies. It won't provide any assistance other than providing calculated ceilings and stop times.

That information alone isn't sufficient to ensure you can do the deco.

Untrained, relatively ignorant divers can simply follow their computers.

...until the day something goes wrong.

...until the day their computer fails.

...until the day they need an alternative option.

...until the day that their dive skills are proven inadequate to follow their computer.

However, we also have to recognize that if you have problems, run low on air, can't control bouyancy etc. the little computer isn't going to do much for you.

Exactly. Recognition of that fact is what makes this a technical diving debate, rather than a recreational ​diving debate.

 

[MXGratefulDiver]

Actually they DO.... provide fly by wire or whatever the hell that means. That is one of the dangers of this type of diving. It is very simple.. follow the computer, exactly like you do when doing a recreational no-deco dive..It is misleading to say that modern dive computers can not be used to execute deco dives (especially short ones at moderate depths). If that were not so, I most certainly would be dead.

Untrained, relatively ignorant divers can simply follow their computers. I had an uncertified buddy who taught himself to snorkel and then to scuba and then to dive short deco to 165 ft all without much more than being somewhat of an athlete and also reading the computer manual. I did deco dives with him on his boat and never knew he had no training (nor even a competent mentor) for like a year before I found out. He was not much of a reader and i don't know if he even read diving books.

However, we also have to recognize that if you have problems, run low on air, can't control bouyancy etc. the little computer isn't going to do much for you.

All of this is assuming, of course, that they understand what their computer is telling them. There are very few ... if any ... standards in dive computers. Most divers who use them don't really understand how they work, and can't be bothered to find out. It's all very easy ... you just read the numbers and base your dive on what the computer is telling you.

Until it isn't.

I did a dive with this fellow a few years back ... pretty experienced diver, so we did an aggressive profile on one of our area's better walls. We're cruising along at 120-something feet when he suddenly takes off up the wall ... without any warning or attempt to indicate to me what the problem was. Thinking he might be running low on air, I followed him up at a rather fast pace till we reached the top of the wall at about 40 fsw ... at which point I stopped and watched him continue upslope toward shore. I decided that we'd been down there a while, and I didn't want to risk injuring myself since he was clearly headed in and didn't attempt to look at me or indicate what the problem was. I waited a few minutes, then began slowly making my way upslope toward where I had last seen him heading. At about 25 feet I see him swimming back down toward me ... and when we reunited he signaled for us to head back down. I waved him off and signaled that we maintain depth ... after a few minutes we headed to safety stop, and then surfaced. Upon surfacing I asked him what that was all about. His answer ...

"I looked at my computer and it was telling me to go to 10 feet and wait 6 minutes. So I did."

:shocked2:

The dude was a divemaster at a local dive shop, and didn't comprehend the meaning of "ceiling". I had to explain to him what his computer was really saying ... then had a few words to say about the "wisdom" of chasing off upslope without letting your dive buddy know what was going on.

That dive did make me wonder how many people using dive computers to shape their profile actually understand what the computer is telling them ...

... Bob (Grateful Diver)

 

[VooDooGasMan]

NWG this is why the RDP should be taught in OW, and even go further and teach what to do if you do go into deco, so navy tables or alike.
I can trust my air consumption and depth of a dive in shallows if a computer and timing, analog depth gauge all failed, enough to stay down to accomplish deco.

Divemasters are taught how to teach scubaskills and get there card, and just really need to be taught so much more.

Knowing the navy tables gives the whole deco a great perspective on how to plan the dive with the amount of gas you have and after so many times it is automatic on how deep you go and how much gas you use for that area of diving(cold or warm water) Without knowing the deco tables, I can see how divers get confused on what the computer is reading. I wonder how many times the diver slows down when he reads the warning blinking to slow ascent from bringing the gauge up to fast to read it.

 

[boulderjohn]

Knowing the navy tables gives the whole deco a great perspective on how to plan the dive with the amount of gas you have and after so many times it is automatic on how deep you go and how much gas you use for that area of diving(cold or warm water) Without knowing the deco tables, I can see how divers get confused on what the computer is reading. I wonder how many times the diver slows down when he reads the warning blinking to slow ascent from bringing the gauge up to fast to read it.

Over the past few days I have been trying to get you and others who advocate deep air diving to define what you mean by deep air bounce diving. If you look at post 243, you will see that I asked people to answer some questions that will define what we are talking about. Since I asked those questions, several people have answered with their own personal responses, but I suspect those answers do not represent what people like you believe. I am particularly interested in your views because I am not sure how you have been defining the practice in your many posts on the subject. I would really appreciate it if you would tell us exactly what you mean, and I would especially love it if you would answer those questions specifically.

 

[MXGratefulDiver]

NWG this is why the RDP should be taught in OW, and even go further and teach what to do if you do go into deco, so navy tables or alike.
I can trust my air consumption and depth of a dive in shallows if a computer and timing, analog depth gauge all failed, enough to stay down to accomplish deco.

Divemasters are taught how to teach scubaskills and get there card, and just really need to be taught so much more.

Knowing the navy tables gives the whole deco a great perspective on how to plan the dive with the amount of gas you have and after so many times it is automatic on how deep you go and how much gas you use for that area of diving(cold or warm water) Without knowing the deco tables, I can see how divers get confused on what the computer is reading. I wonder how many times the diver slows down when he reads the warning blinking to slow ascent from bringing the gauge up to fast to read it.

NAUI tables already give you contingencies for accidental deco ... but we stress these are strictly emergency procedures.

I do not advocate teaching deco procedures to brand new divers ... there are simply too many skills to learn that require bottom time before attempting deeper, more aggressive dives ... and explaining too much too soon WILL be taken by some as an advocacy for trying it.

I do go into some detail about decompression during the deep diving portion of Advanced Scuba Diver, but I also emphasize that this class in no way conditions or qualifies them for decompression diving ... and that such dives are to be avoided until they receive further experience and training.

... Bob (Grateful Diver)

 

[ajduplessis]

I would like to add to these very good points around DC used as a guidance tool.

On my previous dive complacency caused me to make mistakes in DC settings. You see the previous dive I did was a sea level (A0) and I never changed it to the dive we planned (now @1500m/4900ft above, A1 or even A2) and on nitrox 29. To add to the mix we also discussed to do a light deco as NDL at this altitude runs out quickly diving to 30m/100ft. I also adjusted my Suunto RGBM to 50% the previous day to do some tests and never changed that back either. Diving at altitude with ean29 to 100ft with deco obligations on a sea level and algorhytm reduced DC settings. Thrust me this happens quickly ... you set the nitrox after testing the gas without checking the rest and eager to get wet.

Needless to say when my buddy indicated 15min deco/ascent time and I still had 20min NDL left I knew something was wrong. We ascended and I followed his profile out with a extended O2 stop. We both dived doubles with O2 deco stages.

In short what l want to get at is that DC is a tool and will guide you based on predefined parameters, it has no understanding of whats happening around you. There is no substitution for proper dive planning and running things through old school tables to doubles check basics.

My few cents to this well debated thread.

=DevonDiver;6119154]And what will that computer tell you to do if you didn't have enough air to complete the deco? Or... or...or... or....

What I meant was... the computer will tell you the depths to stop at, the time to wait... but it cannot tell you how to achieve that. It won't provide any variables, if you need variables. It won't consider or cater for, any contingencies. It won't provide any assistance other than providing calculated ceilings and stop times.

That information alone isn't sufficient to ensure you can do the deco.



...until the day something goes wrong.

...until the day their computer fails.

...until the day they need an alternative option.

...until the day that their dive skills are proven inadequate to follow their computer.



Exactly. Recognition of that fact is what makes this a technical diving debate, rather than a recreational ​diving debate.

 

[dumpsterDiver]

I would like to add to these very good points around DC used as a guidance tool.

On my previous dive complacency caused me to make mistakes in DC settings. You see the previous dive I did was a sea level (A0) and I never changed it to the dive we planned (now @1500m/4900ft above, A1 or even A2) and on nitrox 29. To add to the mix we also discussed to do a light deco as NDL at this altitude runs out quickly diving to 30m/100ft. I also adjusted my Suunto RGBM to 50% the previous day to do some tests and never changed that back either. Diving at altitude with ean29 to 100ft with deco obligations on a sea level and algorhytm reduced DC settings. Thrust me this happens quickly ... you set the nitrox after testing the gas without checking the rest and eager to get wet.

Needless to say when my buddy indicated 15min deco/ascent time and I still had 20min NDL left I knew something was wrong. We ascended and I followed his profile out with a extended O2 stop. We both dived doubles with O2 deco stages.

In short what l want to get at is that DC is a tool and will guide you based on predefined parameters, it has no understanding of whats happening around you. There is no substitution for proper dive planning and running things through old school tables to doubles check basics.

My few cents to this well debated thread.

Another very good example of how easy it is to do a deco dive with a computer and how easy it is to just follow it and how easy it is to get hurt blindly following a computer.

I have never argued that inexperienced recreational divers should be doing deco, just the opposite, but the computers make things seem deceptively easy. I myself do use a computer to do some short deco dives and never look at tables, but I have done the same or similar dives dozens and dozens of times and I have an intuitive feel for what is reasonable and what is not. I will know (I hope) if the computer gives me wacko info. Another reason why it is so critical to gradually step into this and develop experience slowly.

For example, I have ZERO working knowledge of altitude diving, so if I were to use a computer and nitrox, I would be double checking with tables or something, because I don't put blind trust into a computer..

 

[MXGratefulDiver]

I once did a dive to 230 fsw with my computer set to EAN32 for backgas ... it was very ... very ... unhappy ...

... Bob (Grateful Diver)

 

[waterpirate]

I was still using my nitek duo last year in fla. Forgot to push the button at gas switch and it got pissed off for two days.......
I think most of us get it. It is a tool that has its place but it is not to followed blindly by the un informed.
Eric

 

[RTee]

Here is my two cents on many subjects discussed in previous posts:

First ... my definitions:

Bounce dive: A dive that is accomplished with the sole aim of seeing if one can reach a specific depth he or she has set as a target. Might come with various degree of planning ranging from spur of the moment to ad nauseum planning (depending on how knowledgeable the individual(s) is /are). To me, the dive profile best representing this type of dive is the one done by free divers ...down to as deep as they planned or can go and then straight back up. It may involve deco obligation or not and the amount is mainly unknown unless the individual has set-up a max floor for his dive and then revert to specialized software or US Navy tables for worst case deco obligation(s). For the uninformed or ill-informed diver, it will probably means flying the computer with very little before thoughts/afterthoughts regarding gas management and deco expectation. At the other end of the spectrum you end up with an individual who has done all his planning and dive so equipped.


Light deco dive. I would probably say +1 to the definition given previously to the effect that it is a dive that does incur a deco obligation at depth but would be cleared by the time the diver ascends from the depth he is at (30FPM) up to and including the three minute safety stop. Therefore, in my mind, it could means a deco obligation of some sort at 20 ft and 10 ft considering that it is also the range of depths recommended for safety stop (10 - 20 ft). I included the safety stop for the simple reason that while it may only be recommended for most profiles, certain agencies make it a hard requirement for dives up to and within 3 pressure groups of NDL and those deeper than 100 ft. This type of dive would either be planned or be the result of an unforecasted delay at depth (that would still have been considered as a contingency as part of the pre-dive planning). This dive could range from a very deep deep dive (greater than 130 ft) of very short duration to a slightly shallower dive of greater duration).

Where should we discussed these?...+ 1 with Jax'analogy to sex. We can pretend that if we do not talk about it, non-technical certified divers will not attempt these types of dives (oestridge syndrome). But I think we all know better. In the case of sex, kids talk about it among themselves and will gladly experiment on their own. No doubt that same is already happening worlwide with this type of diving but I am not sure in what proportion though. I am not convinced that by talking about it, it will motivate them to do so. Perhaps quite the opposite for most but those who will attempt it are probably those who enjoyed experimenting about sex in the backyard or the backseat of their car anyway.

Should deco be discussed in greater detail in more basic diving classes? I personally think so, as it is something they should not fear but rather respect, knowing that if one day something does happen while they dive, it will not mean that their entire world will become all loom and gloom and as long as they follow some basic principles they should be OK...Should as any dive table or dive computer manual ever produced always contain that so popular notice that even if you follow these to the letter, it does not guarantee not experiencing DCS.

The reason why such approach might not be possible might be tied to scuba diving becoming an industry of its own many years ago resulting in courses being dumbed down to the lower denominator in order to facilitate voir encourage mass producing and revenu generating especially at the OW level. Not necessarily sure it has been for the better based on the horror stories I read on SB and what I have witnessed personally locally and on vacation. As long as the main motivation will reside in pumping ''certified OW divers'' in 2.5 week (two sessions per week), five weeks (one session per week), two weekends or five day concentrations, there is no doubt that such concept cannot be discussed in greater depths during these courses and no instructors will feel comfy doing so.

Doubles vs air redundancy. I think the underlying principle is to have...redundancy in case of equipment failure. For some it might be doubles, for others, a large capacity single tank with one or two additional bottles (normally referred to as stage) of applicable gas (could very well be air for dive and a mix of air/EAN for ascent/deco based on applicable PPO)


Flying the computer...who can fault these individuals when some agencies seem to be moving away from tables to promote electronic type of dive planner and/or dive computer planning. To understand a concept, it first must be taught, mastered and then you can introduce tools to complement it. It is somehow interesting to note that when individuals decide to make the leap to tech training, one of the first thing they are being taught is to use tables, depth gauge and bottom timer(s) first and use computer as back-up (for those who promote such use).