"Accidental" deco with 1-day group, what to learn?

[geoff w]

OMG! a professional that is even more of a Suunto renegade than we are! Shudder......

Once again fellow divers this is not an approved computer tweak, Suunto approved modification, or a ScubaBoard sanctioned procedure.

Or an indication to the OP kalleth that dive pros and guides aren't necessarily any smarter than you are! Ultimately you're more responsible for your own safety than anyone else, so being knowledgeable about what's going on with the computer you're diving is a good thing

 

[fmerkel]

There are people that are keenly aware of how their computer works and what algorithm it utilizes and how that relates to their decompression safety.

I'm going to take a wild guess that the number is around 15%, probably less. Most people can't even sort out all the different computers, let alone get a working grasp of all the conflicting algorithms utilized IF, you can even find out which one a computer uses since lots of them simply don't make that available. I am NOT criticizing those people. I only have a fumbling grasp of the material. It's complicated. The whole field is a technical mess and even the most well informed and brightest do not agree. For evidence I offer you the thread on deep stops for some eternal and mostly boring reading.

 

[scubadada]

It's easy to be nonchalant about DCS as a novice diver.... and that's partly the fault of the dive industry.

Entry-level scuba courses do their utmost to 'sell' diving as a safe and fun activity. Dive professionals are also in the business of selling divers more diving. Being 'real' about the risks isn't good for sales. The 'real talk' doesn't become transparent until much later, usually.

Scuba diving is a statistically safe activity. That said... many millions of dives are conducted each year. That means...statistically...and in reality... many hundreds of divers get rushed to recompression chambers around the globe annually.

There's nothing on a 'fun dive' that warrants risking life in a wheelchair... especially not an "extra" few minutes underwater gained by pushing NDLs to the limit (or buying a less conservative computer that simply re-defines where those NDLs stand).

Dive to X depth for Y minutes and you have Z risk of DCS.

A conservative computer, versus an aggressive computer, merely defines where in a grey zone that Z is deemed acceptable. It's not black or white.

I fully understand that if a diver has limited opportunity to dive, then their instinct is often to cram as much underwater time as they can on their vacation etc. There are potential consequences to pandering that instinct.

I mean... seriously... just how awesome is that last 5 extra minutes of a dive?

People want to get their 'moneys worth' from a dive. I get it.... and the focus is entirely on the time they spend underwater. I think that's short-sighted.

Getting your 'moneys worth' from a dive is where a dive operator shows you an amazing time underwater and keeps you safe. A great guide dive will show you more in 30 minutes than a crappy dive guide will show you in 45 minutes. A great dive guide will entertain you and educate you. THAT is value for money. Not some d1ckhe@d divemaster who'll risk putting you in a wheelchair in the hope that appealing to people's tendency towards instant-gratification will swell their tips from the trip...

DCS is just not 'frightening' enough... is it? It's very hypothetical from a novice diver perspective (and some not so novice divers...). But dive enough and you'll see it happen... to you or someone you're with.

DCS and other hyperbaric maladies don't trigger an instinctive fear response... like, for instance, you'd get in other outdoor sports like rock climbing, parachuting or white water kayaking. It's hard to gauge risk when you don't get an instinctive, sensory warning of something that can kill you.

Run out of air underwater and you're likely to soil your wetsuit. Aggressively push your off-gassing tolerances and you won't even break a sweat. The more you get away with it, the more silly it seems to fear it... it becomes some sort of 'old wives tail'.... except it's not.

Conservatism is good. Keeping dives shorter and shallower is prudent. As competency grows, don't get more aggressive with the diving... get more intelligent about how, when and why you can extend your limits. Nitrox is good... if used to extend dives conservatively. It's no benefit if it's just another means to make dives more aggressive...and retain the same risks for an extra little bottom time..

Technical diving is the final step... complete freedom to dive as long as you'd ever want. People think tech is just about diving deep... it's not. Technical diving opens up your options for really long and really safe dives....

Hi Andy,

Do you have data to support that a relatively liberal decompression algorithm, like DSAT, has a higher rate of DCS than a relatively conservative algorithm, like Suunto, Mares, or Cressi?

You can always dive a liberal algorithm conservatively, there's nothing you can do with a conservative algorithm, but follow it.

Thanks, Craig

 

[scubadada]

There are people that are keenly aware of how their computer works and what algorithm it utilizes and how that relates to their decompression safety.

I'm going to take a wild guess that the number is around 15%, probably less. Most people can't even sort out all the different computers, let alone get a working grasp of all the conflicting algorithms utilized IF, you can even find out which one a computer uses since lots of them simply don't make that available. I am NOT criticizing those people. I only have a fumbling grasp of the material. It's complicated. The whole field is a technical mess and even the most well informed and brightest do not agree. For evidence I offer you the thread on deep stops for some eternal and mostly boring reading.

The discussion of the NEDU trial has nothing to do with recreational diving

 

[rjack321]

You can always dive a liberal algorithm conservatively, there's nothing you can do with a conservative algorithm, but follow it.

Or trick it by falsely entering a slightly higher nitrox mix (or in tech diving a lower Helium fraction). Or bend it. Or revert to tables. Or follow your buddy's computer. Or skip dives.

Nobody is forced to follow anything. Sometimes the human attached to the wrist actually knows more than the brick on the wrist (sometimes not, but this is the advanced subforum)

 

[scubadada]

Or trick it by falsely entering a slightly higher nitrox mix (or in tech diving a lower Helium fraction). Or bend it. Or revert to tables. Or follow your buddy's computer. Or skip dives.

Nobody is forced to follow anything. Sometimes the human attached to the wrist actually knows more than the brick on the wrist (sometimes not, but this is the advanced subforum)

I would not advise anyone do any of these things. Why not just choose the correct algorithm for you and dive it?

 

[rjack321]

I would not advise anyone do any of these things. Why not just choose the correct algorithm for you and dive it?

This is funny
Oh tell me which is the correct algorithm? Just sticking within the Suunto line should I chose L0, L1, L2 or L3 conservatism? What happens when my buddy is using something different?

 

[scubadada]

This is funny
Oh tell me which is the correct algorithm? Just sticking within the Suunto line should I chose L0, L1, L2 or L3 conservatism? What happens when my buddy is using something different?

Do your homework, educate yourself regarding available algorithms, choose your risk tolerance and choose your algorithm. Then dive it without faking it out, manipulating it, or violating it. How difficult is that?

 

[redacted]

This is funny
Oh tell me which is the correct algorithm? Just sticking within the Suunto line should I chose L0, L1, L2 or L3 conservatism? What happens when my buddy is using something different?

It is not that there is a "correct" algorithm. What we have to choose from is a number of safe algorithms that produce varying safe results under various conditions. But if you step off into the unknown by cheating on the gas mix, then it is no longer clear if and how much added risk is incurred for that and subsequent dives.

 

[doctormike]

This is funny
Oh tell me which is the correct algorithm? Just sticking within the Suunto line should I chose L0, L1, L2 or L3 conservatism? What happens when my buddy is using something different?

Actually, all of those algorithm's are equally "correct", in that they don't result in a significant DCS rate in recreational divers. You can argue about the relative merits of bubble models vs. Buhlman, etc... but the fact of the matter is that any model that is incorporated into a dive computer has a good bit of theoretical work and real world experience to back it up.

Randomly changing one parameter (like diving one gas while telling the computer you are diving another) doesn't have that same support behind it. It's not known how that will affect the underlying algorithm and math. And while a diver may be fine doing that within a certain limited range of parameters (like following another divers computer), it's just not good practice and shouldn't be encouraged.