"Riding your Computer Up" vs. "Lite Deco"

[halocline]

How does one do that? Follow a recommended procedure or just make stuff up?

It's recreational NDL diving, so spending any extra time at a 10 ft stop is optional and doesn't need to follow any sort of deco plan. Basically, the longer I spend on the stop (within reason) the less N2 load I'll have when surfacing. This makes me feel better, less fatigued. So if that's 'making stuff up' I guess I'm guilty.

But, for those who demand some sort of plan, one possible procedure might be to stay at the stop until the computer's N2 bar graph gets out of the 'yellow' and into the 'green' zone, if your computer has something like that. I've done that in the past.

 

[halocline]

Diving deeper than 60' is also not taught in OW certification classes.... Nor night diving. Nor diving with Nitrox or Drysuit (though those are sometimes taught in conjunction with OW cert classes).

Oh jeez.....60ft limit is a 'recommendation', night diving is specifically taught in OW class but is NOT discouraged, nitrox requires a separate cert (I fail to see any relevance)....but diving without a buddy explicitly breaks the safety protocols taught in OW class. You should know all this, you took OW class not too long ago.

 

[bumcikaz]

All right lowviz, gloves are off....here it is! Just kidding.

Before I embarked on technical training, the majority of my dives probably fell into this "light deco" category. When I was doing this most actively, it was the early-mid 90s so nitrox had not really caught on (at least in my area), and there was virtually no public information available on using oxygen or EAN for deco. So, the vast majority of my dives and deco were just done on air. We'd just go out and pick sites at random and dive them on a single AL 80. A very typical profile for me was 130' for 10-12 min of bottom time and a total run time of maybe 28-30 min. Most of my 15' hangs were under 10 minutes and I let my Orca EDGE calculate the dive for me. The longest hang I ever had was 30 min when I messed up. I just dove too many deep repetitive "light deco" dives that day and was a little surprised on my last dive when my computer gave me a much longer hang than expected. That experience and subsequent training taught me that I really like dive planning!!!

Where in MD did you dive to 130'? Which sites?

 

[RyanT]

Hey bumcikaz: I didn't do any 130' dives in Maryland. I'm a somewhat recent transplant to MD. I'm a southern boy originally, so all the dives I was talking about were in the Gulf of Mexico. With that said, there are several 130' + sites out here. Off the MD/Delaware coast there is the Marine Electric at 125ish and the Redford at 140'. I haven't dove these wrecks yet, but hoping to hit them in 2017.

 

[stuartv]

Oh jeez.....60ft limit is a 'recommendation', night diving is specifically taught in OW class but is NOT discouraged, nitrox requires a separate cert (I fail to see any relevance)....but diving without a buddy explicitly breaks the safety protocols taught in OW class. You should know all this, you took OW class not too long ago.

Right. And the point is that there are a lot of things, like Solo, that are part of recreational diving but are not taught in OW class and require or have available a separate cert. Solo diving does not require a cert any more than night diving does. Nitrox generally does require a separate cert and it's still considered "recreational" diving.

Like I said, I would just like to see some substantiation of the statement that all the major agencies define solo diving as not recreational.

Orrr.... we are really OT and can just drop it. You're not going to convince me that solo diving is tech diving and I'm not going to change whatever you think.

 

[boulderjohn]

h

Seems like we have been through this many, many times now. Going into deco accidently is a mistake, one you may or may not be prepared to handle. Going into a short deco obligation on purpose, with appropriate planning and gas is a choice you are responsible for. Just when I was going to give @boulderjohn credit for being reasonably flexible in the rec/tech discussion, I am disappointed.

I am still showing that flexibility, but you have to think it through.

I stand by my posts about doing some light deco in comparison to safety stops. Read it carefully and you will see that I am talking a few minutes of deco. In life we all take chances. I just learned a couple of hours ago that every human with no history of illness has a shockingly high chance of having a seizure at any time--including while diving. We take a chance every time we cross a street or even just drive a car. As some people know already, not many months ago I was at a stop sign in a dangerous intersection, and after doing my best to ascertain that it was safe to proceed, I went forward into the intersection with the 30 MPH speed limit and flashing warning signs. Witness estimates of the speed of the motorcycle that hit me ranged from 80-100 MPH. How am I to avoid that? Never leave bed and risk bed sores?

If I am only talking about a couple minutes of deco as opposed to a safety stop, I am willing to risk not having a redundant air supply. The odds are damned good that I can surface in a flash and be just fine. Go beyond that, and I am going to start getting more serious about the planning.

So here is the conflict. I think some people are too concerned about getting into a little deco. I think some people are not concerned enough. I would love to teach both groups a course, but that isn't going to happen, so I do the best I can.

 

[BRT]

h


I am still showing that flexibility, but you have to think it through.

I stand by my posts about doing some light deco in comparison to safety stops. Read it carefully and you will see that I am talking a few minutes of deco. In life we all take chances. I just learned a couple of hours ago that every human with no history of illness has a shockingly high chance of having a seizure at any time--including while diving. We take a chance every time we cross a street or even just drive a car. As some people know already, not many months ago I was at a stop sign in a dangerous intersection, and after doing my best to ascertain that it was safe to proceed, I went forward into the intersection with the 30 MPH speed limit and flashing warning signs. Witness estimates of the speed of the motorcycle that hit me ranged from 80-100 MPH. How am I to avoid that? Never leave bed and risk bed sores?

If I am only talking about a couple minutes of deco as opposed to a safety stop, I am willing to risk not having a redundant air supply. The odds are damned good that I can surface in a flash and be just fine. Go beyond that, and I am going to start getting more serious about the planning.

So here is the conflict. I think some people are too concerned about getting into a little deco. I think some people are not concerned enough. I would love to teach both groups a course, but that isn't going to happen, so I do the best I can.

I'm curious. If the odds are so high of having a seizure, how come so few of us have them?

 

[DevonDiver]

So here is the conflict. I think some people are too concerned about getting into a little deco. I think some people are not concerned enough. I would love to teach both groups a course, but that isn't going to happen, so I do the best I can.

So, the effect of (percieved) over-zealous algorithmic conservatism is creating a scenario whereby computer users are provoked into second-guessing, or disregarding entirely, the no-stop limits provided by their instrumentation?

Advanced divers are a relatively self-selecting demographic. Those with truly significant experience develop an intimate understanding of their personal relationship with factors like DCS, narcosis, O2 toxicity, task loading and stress management. They limit accordingly and prudently...even if/when such limits are beyond the 'norm' thresholds.

The danger for lesser experienced divers, especially when faced with human factor failings, dive agency marketing hype, a surplus of dive information and superficial peer empowerment from social media, is that they can easily over-estimate their physiological relationship with hyperbaric issues... and mistakenly select themselves for diving thresholds that can damage them.

 

[Diving Dubai]

.

If you are going into deco intentionally, then you are tech diving intentionally.

Only by the definition of US agencies. BSAC teach it as part of the (AOW/RD)
equivalent.

Knowing how to do something - understanding everything about it - and actually doing it are two different things sometimes.

You Stuart are a smart guy, and I suspect can suck up knowledge like a sponge from the text - but how do you know that you've learn't all you need to learn?

One thing about sitting formal training, is that you get an exam for the theory and an assessment for the practical. These obviously allow you to determine what you know and what you don't.


When I complete my rescue diver, both my wife and I scored 100% on the theory. You can learn it by rote almost. You don't need to understand fully the theory, just recognise the text in the given answers.

The BSAC papers are a different kettle of fish. The questions and answers are wordy, the answer's aren't a cut n paste of the text in the books. You have to understand fully the subject and the theory exams are a test of that. In the end I scored 86% but it was a hard score to get. It took a ton of reading and asking of questions, to make sure I understood the finer details.

Often its the fine details that are important.

While I don't subscribe to the commercial model of courses for everything (but understand why this has come about with the customer demanding shorter cheaper "bite size"courses) Certain aspects of divign and improvement of skills really do need to be taught, or at least examined formally.

Deco is one of those subjects - but only in my opinion

 

[KenGordon]

If you're going to have a ceiling, then you should (per tech training) have a redundant gas supply that is more "reliable" than your buddy. With an NDL dive, if you go OOA and your buddy has disappeared around a corner just at that moment, you CAN go straight to the surface. That is not an acceptable answer (going straight to the surface) when you have a deco obligation and you need to be able to, well, live and not get bent if you go OOA and your buddy has disappeared around a corner.

Round here if your buddy disappears around a corner they are generally gone for good. Proper buddy protocol says when you lose your buddy then have a quick look then surface to find them, so the dive is over. Thus a buddy IS available when you go OOA. Anything less is reckless diving, maybe that is what 'rec' really means.

Good luck with heading for the surface from those depths when out of gas.