Tank sizes, DCI, and how they relate...

[CelticRavenVA]

Brian,
yeah I see what you are saying, my point was I don't let my computer count down to 0 min, at 60' I try to keep 5 min (not that I usually have that much air) but if my NDL is 5 min at any depth it is time to start to head up.

Since I just got started diving and love it so much I would like to not get bent and be out of the water for months, or worse in the hospital or dead.....

 

[DepartureDiver]

best thing you can do is a slow ascent and nice safety stops ... a good way to do this is to divide your diving depth in half and do 1 min. there ... divide in half again and do another min. there, etc. until you get to 10' or 15' and then do a few there. Dr. Deco would add "no post dive exercise" or any type of moderate or heavy activity.

 

[pipedope]

The only way to be sure you won't get DCI is to not dive.

Most of us won't accept that option so what do we do?

Accept that DCI is 'possible'
Take precautions to make DCI unlikely
Learn the symptoms of DCI
Learn the 5 minute neurological exam
Get your buddy to learn the 5 minute neuro exam
Watch for signs of DCI in ourselves and buddies after diving
Do the 5 minute neuro if there are *any* signs of DCI
Activate EMS adn call DAN if DCI is suspected and/or confirmed by 5 minute neuro.
If in doubt, get evaluated.

If there is DCI the sooner you get treatment the better the outcome.

Again, DCI is rare in sport divers but if it does happen you want treatment quickly.

 

[simbrooks]

The only way to be sure you won't get DCI is to not dive.

Also dont go into "space" on a rocket, but that is another thing.

I think what CelticRaven was confused about was the same thing i came across from lots of other divers when you ask about getting a bigger tank than an 80. One of the first responses is that they think for some reason you will forget all your training and see how much more air you have, bust your NDL, not do deco stops and die. The response starts as "that is such a big tank, what do you need all that air for?" Then into the safety aspects using air consumption and NDL to try to make you conceed about buying a larger tank. CR, is this the reason, cos your opening statement/question made it sound like you had been fed these lines.

I have contemplated getting some 120's to use with nitrox (with my breathing rate i can only just bust the table NDL value and that would be only breathing at the max depth all the time, not including ascent or decent time - i know not realistic) and shallow dives where you can almost never bust the NDL either, then to double them when i get deco training and use them for that kind of diving - multi-purpose. Although my instructor understood my decisions behind it all, i kept hearing the same thing over and over from other divers who i had to explain it all in detail too before they realised my reasoning. BTW, I am a sane person, in control of my thoughts and actions, i wouldnt ever bust an NDL on a dive, unless i was doing a deco dive after taking the training.

 

[DepartureDiver]

and don't forget that no one has ever been hurt from having too much to breath ... but a single 120 is tall ... too much for me ... that's when I go to a dual rig.

 

[simbrooks]

Air supply, that was my other arguement.....

A 120 is ok for me, i am 6'3" and more than big enough to hold it - now if only they were selling them at a reasonable price again....in fact anytime before august.

At the moment i am thinking of getting those compact/super 80's and doubling those for a while. More than enough air for most things for the next year or two, then onto the 120's after that.

 

[DBailey]

While others have mentioned that DCI is not directly related to tank size, what about other effects on the body?

If you are breathing through a 80 and want to go to a 120 to lengthen your dives, you will be breathing in that much more dry air. The additonal dry air will dehydrate you that much more per dive.

While it not affect you, there may be people that need to consider this before making the jump to a bigger tank.

Are there any other concerns?

 

[DepartureDiver]

If you are breathing through a 80 and want to go to a 120 to lengthen your dives, you will be breathing in that much more dry air. The additonal dry air will dehydrate you that much more per dive.

A good concern. But it is addressed by staying well hydrated before and after a dive. Divers doing long decompression dives will be breathing dry air for an extended time with no ill effects. But they also know to stay well hydrated for the reason you just mentioned.

 

[CelticRavenVA]

Hell no... not trying to break any limits on a deco chart. Just still learning breath control. In fact as I stated earlier, I try to avoid coming close to them at all costs. Go re read how I do my dive planning earlier in the thread.

My dive partner is alot more experienced then I am and while I am coming up with 500 left he is still at or over half a tank. I am a very safe diver, and rely on my trainning not forget it. Just seeing how to have a more enjoyable day for everyone.

Also dont go into "space" on a rocket, but that is another thing.

I think what CelticRaven was confused about was the same thing i came across from lots of other divers when you ask about getting a bigger tank than an 80. One of the first responses is that they think for some reason you will forget all your training and see how much more air you have, bust your NDL, not do deco stops and die. The response starts as "that is such a big tank, what do you need all that air for?" Then into the safety aspects using air consumption and NDL to try to make you conceed about buying a larger tank. CR, is this the reason, cos your opening statement/question made it sound like you had been fed these lines.

I have contemplated getting some 120's to use with nitrox (with my breathing rate i can only just bust the table NDL value and that would be only breathing at the max depth all the time, not including ascent or decent time - i know not realistic) and shallow dives where you can almost never bust the NDL either, then to double them when i get deco training and use them for that kind of diving - multi-purpose. Although my instructor understood my decisions behind it all, i kept hearing the same thing over and over from other divers who i had to explain it all in detail too before they realised my reasoning. BTW, I am a sane person, in control of my thoughts and actions, i wouldnt ever bust an NDL on a dive, unless i was doing a deco dive after taking the training.

 

[simbrooks]

Hell no... not trying to break any limits on a deco chart. Just still learning breath control. In fact as I stated earlier, I try to avoid coming close to them at all costs.

My dive partner is alot more experienced then I am and while I am coming up with 500 left he is still at or over half a tank. I am a very safe diver, and rely on my trainning not forget it. Just seeing how to have a more enjoyable day for everyone.

CR, i wasnt saying that you were doing that, only that people when you suggested buying larger tanks, might have tried to argue that case with you - like they did me, i also dont go near the limits (at this time - give it a few years, more training etc).