decompression without training

[TSandM]

I would highly recommend Mark Powell's Deco for Divers as a single, extremely readable resource on decompression theory.

But understanding gas planning for a decompression dive (remember, you HAVE to have enough gas to complete your deco), and planning a safe profile, are things you can learn from a book.

What you can't learn from a book is that, once you have incurred a decompression obligation, you are truly OBLIGATED to remain underwater, and at a prescribed depth, if you want to finish the dive healthy. This means you have to learn to solve problems at depth, calmly, and without losing buoyancy, trim, position, or track of your team. Can you cope with a freeflow, or losing a mask, or the mouthpiece coming off a regulator, or other like problems, without hanging onto anything and without coming off your depth, and keep enough bandwidth to remember where you are on your schedule and when you need to move up?

Diving under an overhead, whether virtual or real, is the province of people with a fair amount of experience and enough training to be prepared to handle the unexpected, at depth, calmly, expediently, and still manage their dive.

 

[Dr Wu]

Too important to not have more of a safety margin than "a few inches" between a scheduled stop and where I might stray to. But I am an NDL diver, so I'll accept it if you tell me that people routinely hold their stops that well. Clearly too, I will remain an NDL diver, because I am okay with a safety stop that ranges anywhere between 14 and 16 feet, for example.

It's a good thing you understand your limitations. Were you to stray even a few inches from the required deco stop depth this would happen to you; YouTube - Alien - Extended Chestburster

No way around it.

 

[Thalassamania]

Large variation in a safety stop that you really don't have to make anyway is fine; safety stops only exist because recreational divers were routinely making ascents in excess of 120 fpm and a safety stop was a way to slow down the ascent and get them in control for the even more critical last twenty feet or so. Real decompression stops should be handled as careful as possible with respect to depth and so whenever I can, I use a line that tracks the surface as well as it might.

 

[Gilldiver]

If you are diving single tanks such as 72 or 80's it is real hard to get into a decompression range unless you are doing your 3 to 5th dive of the day and hitting the 50-100 foot range. If you are doing one or two dives, it is real hard to get into deco period, but it can be done.

If you are using a big single - 100-135 or have moved into doubles, then we need to have a long talk about gas plan, accent plan/technique, etc. In other words we need to talk about your plan period.

When I started diving, it was a SPG, US Navy tables, a depth gauge, and a watch - you kept track of all that and modified your dive as required. You planed your dive, but if gas got low, you started heading up.

Next, not all computers are equal. Some will have you in deco before others, some have the ability to set conservatism, so you can dive strict tables or add buffers. So two dives doing exactly the same dive can have different accents. One does a safety stop at 10 ', the other had a deco stop at 10 feet or deeper.

As was said earlier, if you are doing a 3 to 5 minute safety stop, you just did a 3 to 5 minute deco stop, they are no different.

But if your computer says you are into deco, then follow that computer and do the deco if you have the gas. Don't panic, just do the time. If you are with a dive master, let him know, if you are with your buddy, let him know, if you are by yourself, we need to have another talk. On a well run boat, they should have a spare tank ready for events like yours, it may even be hanging over the side already, if you are short on air, use it.

 

[AfterDark]

scubasteve0011, in your profile you are AOW / Nitrox. Am I to understand you received no training in decompression during these courses? I hold no such certs so I have no frame of reference of what the training involves.
You should have some kind of training to understand what is happening to you and what you are doing. Going along with a person or people whom are willing to go slow and train you is an excellent way to learn. Doing your own research beforehand gives you an edge.

 

[dkktsunami]

thanks for all the advice.. from what Ive read so far seems like occasionally going into deco is not a deadly sin, but I should get some training before planning to do a deco dive

"Occasionally going into deco" by accident or inattention is okay but "planned deco" requires training? Realignment of priorities and logic might be a better goal in this case.

 

[Web Monkey]

Well I guess there is your answer to the question of "going into deco" if you have a "bad" computer. Apparently you are going to either "get lucky", bent or die. You might also drown (option two) but apparently that is different from death so keep that option in mind should the opportunity arise.

If you're going to be snotty about something, at least be accurate.

It's entirely possible to drown and not die. That's one of the reasons pools have lifeguards and not body bag dispensers.

That's with a "bad" computer.

So make sure you get a "good" one.

The point wasn't that a good computer makes a good diver, it's that a bad computer could give the diver a potentially fatal surprise.

Finding that your computer can call for 20 minutes of deco when you have 3 minutes of gas left isn't something you want to discover by accident.

Terry

 

[UCFKnightDiver]

scubasteve0011, in your profile you are AOW / Nitrox. Am I to understand you received no training in decompression during these courses? I hold no such certs so I have no frame of reference of what the training involves.
You should have some kind of training to understand what is happening to you and what you are doing. Going along with a person or people whom are willing to go slow and train you is an excellent way to learn. Doing your own research beforehand gives you an edge.

AOW and Nitrox as a rule does not come anywhere near decompression etc.

 

[AfterDark]

AOW and Nitrox as a rule does not come anywhere near decompression etc.

Thanks for the info. I'm still trying to digest it, seems unbelievable to me. What is advanced about AOW? Isn't Nitrox for staying down longer and/or going deeper? No decompression talk there either. OK then thanks again. WOW

 

[UCFKnightDiver]

yeah to be honest the Advanced in Advanced Open Water is a joke as well as the class imo, it ought to be called Open Water 2