No Deco Cave Diving... worth it?

[victorzamora]

One thing I found, despite not wanting to do any deco diving, was that it becomes well worth it when you start cave diving. Not all of your dives will require deco, especially if you're diving Mx frequently. It seems to me like most dives in Peacock don't require any deco (or little deco).

Deco training, for me, is worth it....and here's why: The emergency situation you described (get stuck, take longer to exit, accidentally hit deco). I dive very conservative settings, and I do so intentionally. If I have to blow some deco, I can do so without too much stress because I'm diving conservatively whereas more liberal settings would probably have me out of the water. Maybe too safe, but it's worth the extra few minutes to me to help mitigate the risk. The biggest one, to me, is deco training unlocking O2. I, personally, am a fan. Having a little 40 of pure O2 in the cavern zone makes me feel warm and fuzzy, even on dives planned to be NDL dives. It's nice to have at the dive site even if you don't take it in the water with you. Deco training can't hurt, and actually helped me (extra time coaching with a good instructor). Just because you have the training doesn't mean you have to do deco dives....or long deco.

 

[TSandM]

I've been cave diving in Mexico for the last 7 years. I have turned two dives total because we were going to end up in deco if we kept going. My average dive is between 2 and 3 hours. So yes, there is LOTS of great cave diving that doesn't involve doing staged decompression!

 

[phoenix31tt]

I've been cave diving in Mexico for the last 7 years. I have turned two dives total because we were going to end up in deco if we kept going. My average dive is between 2 and 3 hours. So yes, there is LOTS of great cave diving that doesn't involve doing staged decompression!

does the ability/training to do deco dives ease your mind when cave diving?

 

[markmantei]

While the others have answered your question pretty thoroughly, I would add this. There is no magic to "deco" diving, essentially even recreational dives are deco dives to a some extent. The technical training you do will show you how to prepare for and manage the additional risks. Having a decompression obligation means having a virtual ceiling, you can't go above a certain depth. Being in a cave you have a physical or hard ceiling. Frankly in many respects the cave diving is more dangerous than having a decompression obligation (obviously both have their risks and this is highly dependent on the cave and/or dive plan).

 

[ucfdiver]

biggest thing to think about regarding unplanned deco is this.
You plan a dive to NDL's using full thirds, or even sixths, but we'll use thirds because that's full cave limits. So you go in a third, out takes about a quarter usually, but you turn assuming it will take same amount of time in and time out. Say 20 minutes in, 15 minutes out, puts you 5 minutes ahead of your NDL's. What happens if you have a siltout, lose your buddy, have an emergency where you are out of air, and it takes 10 minutes to fix that situation and now your exit instead of 15 minutes is 25 minutes. You've just blown deco on a dive that shouldn't have gone in. Now you have the psychological issue of having blown NDL's without being deco certified compounding the other issues that have already happened. You aren't likely to run out of gas, but just because you're deco certified doesn't mean you have to do planned decompression, just that if it happens, it's no big deal.

Are you seriously stressing over staying 5 minutes longer than your NDL in an absolute worst case scenario dive? In 100ft of water that's 3-4min of deco or (more reasonably) in 60-80ft average depth that's <3min deco.

That's a perfect example of measuring with a nanometer and cutting with an axe.

 

[tbone1004]

I'm not stressing, all I'm saying is that some people get wooged out when they blow NDL's, so if his wife is already not wanting to do decompression they either have to cut the dives way short to allow for the extra time at depth for conflict resolution and still not blow ndl's, or just take a basic back gas decompression course to remove the possibility of worrying about your NDL's compounding an already bad situation.

 

[nimoh]

yeah, those 3 hour NDL cave dives in Mexico are way too short

 

[boulderjohn]

If the concern about taking a course teaching decompression is a fear about the horrors of going into decompression, then maybe the best reason to take the course is to get rid of that fear. Open Water training does a great job of scaring the bejeezus out of students in terms of staying within decompression limits, and open water dive operators keep that terror going by repeatedly warning divers not to go into deco on their scheduled dives. This can cause fears to be blown out of proportion.

I took a liveaboard trip to the Galapagos a number of years ago, and my roommate/dive buddy suddenly started heading to the surface without warning. I went up after him, catching him at 40 feet to see what was up. His eyes wide with terror, he showed me his computer. It was a model I knew well, and I saw nothing of interest. He did not look at it himself--he just started to ascend again. I stopped him again just above 20 feet, and he again showed me his computer, which was now counting down a 3 minute safety stop. WTF? We reached the surface, and he told me, his voice choked with terror, that he had almost gone into deco! It turned out that at depth, he had seen he had only a few minutes of NDL time remaining, and he had immediately started a panicked ascent. When I caught him, of course, the computer was now saying he had about 45 minutes of NDL. When I told him that, he refused to believe me--how could he have had more time after ascending than he had when he started? He spent the rest of the surface interval telling everyone how close he had come to going into deco, still believing his rapid ascent had saved him from a horrible death. It took a lot of convincing to make him believe that the worst case scenario he would have faced with a minor violation of the NDLs was a modest increase in his safety stop time.

If the reason people are avoiding a decompression procedures class is a fear like that, then such a course is exactly what is needed.

 

[TSandM]

Boulderjohn has a good point! In addition, the physical skills of a decompression class -- managing a slung cylinder and doing gas switches -- are relevant to even non-decompression cave diving. Even with my SAC rate, I can't do three hours in a cave on two backgas tanks .

And yes, having an understanding of decompression and training in staged decompression diving makes me much more comfortable about something like our dive in Regina, where we turned on accumulated time and depth, and I wouldn't have been unhappy to have done a little backgas deco in the cavern zone, if I thought it would be helpful. (I want to go back one of these days with an O2 tank, because the cave was just getting absolutely spectacular where we had to turn.)

 

[phoenix31tt]

Spoke to her about the discussions here... her response was oh so deco diving is when you have to do the extra stops etc when ascending... turns out what boulderjohn said was absolutely right... it's the fear instilled in us while open water diving she was just thinking about that...

she doesn't feel so about deco now and she did say it makes sense to know it rather than need it and NOT know what to do...