Darwin Awards of Diving

[The Chairman]

How does ones "buddy" rack up 21 minutes of deco without knowing? And how did you not have any deco?

This happens quite often, and my bet is that his buddy was diving a Suunto with a positive conservatism and he was probably diving an Oceanic product or similar. Add an average 5ft differential in depth and the disparity can be amazingly huge.

This past Saturday I dove two PDCs. One was based on DSAT and the other on Buhlmann ZHL-16C. There was an 16 minute difference in Deco. I had enough gas, but I was cold and it was the last dive of the day. I was also on O2 which was not factored in on either PDC. Sure, it locked out the one PDC, but I am not diving until this weekend.

 

[Mr Carcharodon]

Caisson workers used to do what would be the equivalent of very serious decompression dives back in the 19th century without any decompression afterward and they didn't get bent from it more than once in a while. Of course that didn't make it safe. When you're regularly taking those kinds of risks it's just a matter of time before your luck runs out.

Remember that “bent” covers a broad range of symptoms. For the caisson workers there appeared to be only reporting on the most severe cases involving paralysis and death. But if we included all minor symptoms probability of DCS in the caisson workers would have approached 100%. But then it is not relevant to compare someone who ran 500 minutes over a NDL to someone who ran 5 mintues over. Also remember that at least for the DSAT tables while a limit is established that is not a DCS threshold.

 

[Mr Carcharodon]

My wife and I are both experienced divers. I'm an aerospace engineer. I have reviewed many computers. Reviewed and started writing my own VPM-B software. I have also reviewed many many pages and documents on decompression and decompression models. So after all that research, I hope I understand what the little box on my arm is doing.

day out. Over and over, well one day he screwed up a little bit and took a major hit.

What is your probability of getting bent in this case? Still very low it would appear from the evidence. The diver involved may have just been making a different risk assessment than you would have, which may have been OK for him and not you. It is important not to be blind to the empirical evidence life gives us. You can use VPM as your gold standard but remember that the critical gas volumes are just back calculated from empirical studies as well. Some of those studies like the DSAT study defined safe limits but not DCS thresholds. So we know there is margin against them, just not how much.

Anyway I tend to be pretty conservative on ascents myself so I am not suggesting that anyone do what the diver descibed did. Because it did not appear he was making informed decisions. But paying attention to what your body tells you is important as is not putting undue faith in any black box.

 

[Blackwood]

What is your probability of getting bent in this case? Still very low it would appear from the evidence.

Exactly.

The suggestion that breaking some model gives one a good chance at being bent doesn't hold up to scrutiny. Breaking a model means you broke the model.

This happens quite often, and my bet is that his buddy was diving a Suunto with a positive conservatism and he was probably diving an Oceanic product or similar.

Or a VR3. Holy hell can those be punishingly conservative.

 

[Guy Alcala]

Yep. The funny thing is, I've read a lot of good reports about Gekkos. Not sure what I'll get to replace it, but I think I'll print out a copy of your post and show it to my LDS, and see if they can get any feedback on it.

I like Suuntos; I use an old Suunto Favor that I bought used out of a rental department and have never had any problems other than the #@$%&* touch contacts when the unit is wet and I'm trying to call up the log, but I've learned how to deal with that. I prefer the primay display on Uwatecs a bit more, as my primary interest is depth and dive time: On a Uwatec they're side by side on the top line and about the same size, on the Suuntos depth is on top (or top left), dive time is bottom right, with NDL in between. But it wasn't just the Gekkos that were having problems with the depth sensors; I know the depth sensor on the D3s were failing pretty regularly about the same time. You could search SB back about that time and find plenty of posts.

The problem seems to have been a bad batch of sensors from a supplier; I don't think it's an inherent problem to Suuntos, as I haven't seen or heard a similar volume of complaints recently. But maybe I just haven't been paying attention. If it's out of warranty you're probably SOL in any case.

Guy

 

[scubafanatic]

That is not nearly as bad as "Computer Man" as I like to refer to him.

Wife and I where on vacation at a tropical island, week of diving. Said diver gets on the boat, have the usual how ya doing get to know you conversation. Guy seemed like an OK diver, put gear together clean and smooth.

First dive of the morning, we where using 32% nitrox, said diver was using air. We do a wreck dive to 100 feet, wife and I see a huge moray eel and follow him down to 110 for a bit. Still staying within our MOD, I notice said diver following us. Wife and I had a nice dive, and headed back to the line, all the while said diver following us. When we hit the line we where really really close to the NDL. So I kind of look at my wife and she looks at me as we look at said diver on AIR doing the same profile as us. :shocked2:

I'm thinking to myself if I'm a nats behind to deco, he has got to be in deco. We accend, and start doing stops. Said diver accends past us and heads for the boat. Wife and I exchange looks and wait to hear the boat fire up and take this guy to the chamber.

Needless to say, we finish up our stops, get on the boat. Said diver is on the boat, fine as can be, starting to change over his tank for dive 2. After switching tanks I see him grab a bag, take off his dive computer and pulls out another one. He must have had almost a dozen computers in the bag. So, feeling as if I'm going to explode if I don't ask, "wow that's a lot of computers, why so many?" Said diver responds "Well, I use them and when I surface they say violation or something like that and wont work on the second dive. So I just get a new one so I can keep diving"

At that point in time I just walked away shaking my head in disbelief. I did not just hear that did I? So during our SIT I get a chance to talk to the DM in private about said diver. Needless to say he did not dive the second dive and we did not see him on the boat the rest of our trip. I don't know if he is still alive or not.

...no freakin' way dude !!! ...that's sooo awesome...really does take the cake ! ...there's no way in H*LL that's guy is still alive...NO WAY !

 

[scubafanatic]

I once witnessed a new diver surface from a dive, as he gets back on the boat he lets the DM have it for giving him a faulty octopus on his regulator set-up. When the DM asked the diver to explain what happened he stated that after his primary regulator ran out of air on his safety stop he switched to his octopus only to find that it wasn't delivering air either, forcing him to do a CESA.

OK, this one is pretty awesome too! ...if I were the DM on the receiving end of this idiot's 'rant' I'd tell 'professor' there he should have just switched to his snorkle !

 

[scubafanatic]

If the regulator was used on a stage bottle or slung pony, it's definitely conceivable that the first stage could flood, or need to be reseated/swapped for one reason or another. This probably shouldn't be a huge consideration for recreational diving, but regulators are expensive, and many people buy them taking into account the possibility of future training (and salesmen won't hesitate in listing future-proofing as a benefit while selling something).

I certainly wouldn't want to flood a regulator just to test it, but I don't think I'd go around laughing at a guy who was told by his LDS that it was doable, and tried to test it in the safety of shallow water.

I'm guessin' the LDS 'forgot' to mention doing an UW hot swap will void the warranty...I'm not aware of any product warranties that cover 'blatent abuse' !

 

[scubafanatic]

Similar passenger on our boat. But he only had TWO computers. One for the first dive, one for the second dive. "The first one always starts beeping and flashing towards the end of the second dive, so I just swap computers between dives. Completely solves the problem."

Yeah - REDUNDANCY!

...what an idiot! ....doesn't he know he can just remove the battery and reinstall it to stop those pesky alarms ? FOOL !

 

[elmer fudd]

Remember that “bent” covers a broad range of symptoms. For the caisson workers there appeared to be only reporting on the most severe cases involving paralysis and death. But if we included all minor symptoms probability of DCS in the caisson workers would have approached 100%. But then it is not relevant to compare someone who ran 500 minutes over a NDL to someone who ran 5 mintues over. Also remember that at least for the DSAT tables while a limit is established that is not a DCS threshold.

My understanding is that pretty much all the caisson workers got severely bent eventually, (and probably had numerous lesser incidents), but that was pretty much my point. They could do a "dive" that would be considered practically insane today and more often than not they got away with it. Eventually however they did get bent and their accounts indicate that long term it was a practically suicidal profession.

The guy who just ignores when his computer tells him to decompress is taking one hell of a risk IMO. If it were to happen to me once and I surfaced, I probably wouldn't freak out, but I sure wouldn't be going down for a second dive either. That would be about the time I decided to head for home, take it easy and carefully observe myself for any symptoms of DCS. When you do something foolish like that on every dive and then do repetitive dives it's just a matter of time before something's going to happen.