"Accidental" Deco

I was on a boat dive today and we had two people go into deco "accidentally". I am wondering how can you accidentally go into deco? I have had a few computers and they all say it as big as can be on the screen while you are diving how long you have until deco. If it gets low you head up as to not incur a required deco since as a basic diver you are not qualified to get into deco. I guess that this is just a big rant that if you cannot keep track of the few things that are required that you should not be diving. If you can't watch your gauges, don't go in the water. You become a hazard to not only yourself but to everyone that is with you on the dive. I don't really know any other way to get a persons attention that if you are not qualified for something don't do it. Plan your dive and dive your plan and you will live to do it again.

Yes, an untrained diver should not go into deco. However, if you do acquire a one or two minute ceiling, it's not a big deal. It will usually clear after a slow ascent. If not, you do a 5-minute safety stop instead of a 3-minute safety stop. You will live to dive again.

Some of them probably could not read the computer and do not understand all those alarm and flashing numbers!!!!
I remember many yrs ago on a safety stop after a deep dive, the local dm would not let a diver to surface after 5 mins. She had managed to accumulate 13 mins deco penalty and not realizing it.

We had one diver with about 10 minutes of deco and the other had racked up over 16 minutes of deco and we had to tell him to go up after we got his attention and checked his computer, he was completely oblivious. Most people don't realize how fast deco racks up and get caught with a lot before they even know what happened.

That's why you should know how to read a deco obligation on your computer, and what to do about it even if you don't intend to get there. Things can happen. Some divers I was with on a dive yesterday had to wait about 3 minutes for a massive school of jellyfish to clear the anchor line.

Like Vladimir said it cleared during the ascent. They were aware and knew what to do.

To answer your original question (I realize that it was essentially a rhetorical one), the #1 reason for getting into an unplanned deco situation is diver inattention. There are certainly other factors which could cause it: dive computer malfunction, incorrect nitrox setting, incorrect personal adjustment/altitude setting, helping effect a rescue, etc. In all of these cases (except for computer malfunction), the diver should still be "aware" (or at least anticipating) that he's exceeded NDLs.

Newer divers can get really flustered if their computers start beeping/flashing at depth. It's a combination of not being familiar with the deco mode of the computer in question and perhaps a touch of narcosis. I've witnessed more than one diver who freaked out a little when this happened. It can lead to a dangerously rapid ascent if the diver is not responding in a calm, appropriate manner.

One thing that some divers don't appreciate is that two divers can be diving an identical profile, i.e. have the "same" nitrogen loading, and be on either side of the "deco line." Or to put it another way, the dive profile can be such that the diver using the more conservative computer enters "deco" mode whereas the the diver with the more liberal computer could still be well within the "yellow" nitrogen-loading zone with double-digit NDLs available. Let's say both divers ascend under control, complete a 3 min. stop at 15 fsw...and then surface. The diver with the more conservative computer is in "deco violation" mode flashing arrows to the diver to descend below the ceiling immediately. In contrast, the diver with the more liberal computer is happily calculating surface interval time. In this example, which diver is exposed to the greater DCS risk?

bs63366:

...........//...... I have had a few computers and they all say it as big as can be on the screen while you are diving how long you have until deco. If it gets low you head up as to not incur a required deco since as a basic diver you are not qualified to get into deco. I guess that this is just a big rant that if you cannot keep track of the few things that are required ............//..........

Click to expand...

Start with gas management before you get too righteous.

When I "accidently" go into deco it's on purpose. What's the big deal? Deco ain't rocket science, it's not some kinda mystery. It's like a saftey stop only longer and ya gota do it no excuses if you ain't got the gas you're SOL.

bs63366:

We had one diver with about 10 minutes of deco and the other had racked up over 16 minutes of deco and we had to tell him to go up after we got his attention and checked his computer, he was completely oblivious. Most people don't realize how fast deco racks up and get caught with a lot before they even know what happened.

Click to expand...

Wow, that's surprising. Most basic divers don't have the gas to maintain a proper reserve and get into that sort of deco. What tanks were they diving? Were they day diving or was it a series of repetitve dives over multiple days? Were they diving Suuntos?

vladimir:

Wow, that's surprising. Most basic divers don't have the gas to maintain a proper reserve and get into that sort of deco. What tanks were they diving? Were they day diving or was it a series of repetitve dives over multiple days? Were they diving Suuntos?

Click to expand...

My thoughts exactly. I was thinking that they must have been low on gas as well. Gas management issues usually go hand in hand with accidental deco obligations and the slippery slope gets out of control faster and faster and on and on compounding into a nasty accident requiring more than a little harmless deco in these situations.