Would you really know what was going on if your computer went into Deco...?

[Spectre]

Different computers may have different instructions. Mine, IIRC, doesn't tell you to go to the ceiling and wait. It gives you an ascent time, and a ceiling. It doesn't tell you to go to that ceiling.. it just tells you not to exceed that ceiling and how long to make your ascent.

 

[Northeastwrecks]

Would you really know what to do...?

Have you ever done it...?

I wonder if it might be a good idea to intentionally run it over a couple of minutes in the red in very calm and controlled conditions then work off the Deco obligation plus 3-5 minute Safety Stop as well - all as a practice & learning session?

I've asked a few, and the most common response is: "If it beeps, I'll know I have a problem to ask about." :klo:

don

No, I have never unintentionally taken my computer into deco. Moreover, since I use a bottom timer and a Stinger in gauge mode, I don't get computerized recommendations on how to bend myself.

I took a Mosquito into deco once; however, that was a rescue in which I knew that I would go into deco. I had a plan set before I dropped. I also had a buddy standing by above me and could have deco'd off a Hooka at 20 feet if I'd really needed it.

Deco diving is an overhead environment. By definition, you cannot ascend directly to the surface.

Accordingly, you could also ask (1) should I go cave diving in my AL80 single; (2) should I penetrate that wreck without training or a reel; or (3) can I go ice diving, just to see what it feels like and without building doubles? It would make as much sense and be just as potentially deadly

I agree with Spectre and the others who have posted. If you want to get used to the concept of deco stops, do them while still within NDL's.

I'd also suggest that anyone who's computer goes into deco unintentionally should proceed to the nearest shop that offers OW training and take some. That person has a very serious problem with situational awareness and dive planning.

 

[MXGratefulDiver]

Yes, I've taken my computer into deco on several occasions ... usually when doing long dives in the 100-120 fsw range. I'll typically do a 1-minute stop at around 60 fsw, then make sure I ascend no faster than 10 feet per minute after that. My computer usually clears the deco obligation before I hit 30 feet. Regardless, I still give it 5 minutes at 20 fsw and 3 minutes at 10 fsw. My body thanks me for it, even if my computer doesn't care.

... Bob (Grateful Diver)

 

[diverrick]

My new DC has a "demo" function, where you can set it up, and run it down to any depth, for as long as you wish, and then come back up and do the required deco stops. It was really interesting if you stop deeper then it required and watch how it all ends up. Much safer than going out and doing it in real time! It does this for repetitive dives, and Nitrox demos as well. So you can actually do the dive profile first, in your comfortable boat or room, and see how it's going to go, but I do agree that one should not depend completely on the DC for deco info.

 

[SDAnderson]

OK I'll expand. While diving in Cozumel, my Vyper enterred a required Deco obligation of about 18 minutes on my second dive of the day. This seemed excessive at the time but I obliged and much to the dismay of our DM (Dive Paradise).

18 minutes of unplanned deco? What kind of profiles did you have that day?

By way of example, using fairly conservative (10/85) parameters, a 30 minute dive to 100 feet on air will incur about an 18 minute deco obligation. With a 1 hour surface interval, you can do the same dive again for 20 minutes and still only incur a 17 minute decompression obligation. There are a lot of variables to consider, but Suunto just isn't so conservative that it would rack up that kind of decompression without some serious effort on your part.

That said, I would have done the deco as the computer ordered, especially if you don't know how to plan your own deco. The alternative, blowing off deco, is whoop-*** scary unless there is a chamber right next door. I'd also be very careful in the future - this stuff will kill you if you aren't careful with it.

 

[Genesis]

18 minutes of unplanned deco? What kind of profiles did you have that day?

By way of example, using fairly conservative (10/85) parameters, a 30 minute dive to 100 feet on air will incur about an 18 minute deco obligation. With a 1 hour surface interval, you can do the same dive again for 20 minutes and still only incur a 17 minute decompression obligation. There are a lot of variables to consider, but Suunto just isn't so conservative that it would rack up that kind of decompression without some serious effort on your part.

That said, I would have done the deco as the computer ordered, especially if you don't know how to plan your own deco. The alternative, blowing off deco, is whoop-*** scary unless there is a chamber right next door. I'd also be very careful in the future - this stuff will kill you if you aren't careful with it.

Actually, the Suuntos are pretty bizarre on this account.

When you cross the deco threshold, you magically get at least four minutes of obligation, because they count your 3 minute "safety stop" in the ascent time. So you go from "zero" to an ASC TIME of four or even five to six!

Now the ironic part of this is that if you start doing a deco-style ascent profile, you'll probably clear the obligation before you get to the safety stop depth!

The other thing with the Suuntos is that you will get SEVERELY penalized for rapid ascents, less than one-hour SIs, or both. If you committed one of these evils on the first dive, you could easily find yourself with an extremely short second-dive time before you enter mandatory deco.

Finding yourself with an 18 minute deco obligation that is unplanned is very un-good. As others have noted, you can bend the bejeezus out of yourself that way, particularly if you did not do the proper gas planning for it and are forced out of the water early due to lack of breathing gas.

 

[Snowbear]

I've taken my Vyper along on planned deco dives where I used a V-planner schedule. Scarey part was, on each dive, the Vyper "cleared" while I still had 5-10 minutes of deco obligation via the schedule. Conservative as it may be, I decided it was not in my best interest to trust the Vyper to calculate deco schedules for me. 18 minutes is a long deco if it was unplanned!

 

[Genesis]

The Suuntos are only conservative compared to other NSL computers.

I've found the same thing Snowbear when I've had my Vytec in "computer" mode on a Vplanner profile - the computer clears first. It may be a useful backup, but I wouldn't dive it as a primary instrument.

 

[scubasean]

I've taken my Vyper along on planned deco dives where I used a V-planner schedule. Scarey part was, on each dive, the Vyper "cleared" while I still had 5-10 minutes of deco obligation via the schedule. Conservative as it may be, I decided it was not in my best interest to trust the Vyper to calculate deco schedules for me. 18 minutes is a long deco if it was unplanned!

Although I'm not deco trained, I did several comparisons last year between vplanner and the Suunto dive manager sim software....and I vowed NEVER to use the vyper for deco, except as a bottom timer....LOL

There were much too many differences, and the vyper always had me out before the vplanner wanted me out.

 

[Scuba]

Would you really know what was going on if your computer went into Deco...?

Would you really know what to do...?

....... - all as a practice & learning session?

don

In order to know what is going on and what to do - start with the learning session. Learn decompression diving. That will answer these questions and many more. You can then practice all you want.