Going into deco

[BRANDY]

Okay . . . It's confession time. This came up over the weekend, where my husband did a repetitive dive and racked up what his Mosquito told him was 22 minutes of deco (which is kind of absurd on a dive with a max depth of 90 feet, but where the vast majority of the dive was spent around 50 to 60, but that's what the instrument said). Since it wouldn't give him any credit for time served below 20 feet, he ended up with about a ten minute hang at 10 feet, which he did. Gas was no issue.

Yeah, I know, I know, you shouldn't do decompression diving unless you're deco certified and are diving doubles and have appropriate decompression gases and do your gas management ahead of time. But I suspect that Peter's not the only one who's ever done this. In fact, I know Catherine does deco from time to time.

My question is: Who has deliberately gone into deco on a recreational dive, and how did you figure out how much deco to do? Did you do what your computer asked for? Did it make any sense?

Same thing for me this weekend. My suunto hit me for about 11mins of deco on a 100Ft dive and gas was a problem. Needless to say I blew off about 8 mins of it.

 

[liuk3]

1. Communicate to your buddy that you have a deco obligation ... do this by tapping your computer, holding your hand up with pinkie finger extended (ASL sign for D) and then use your fingers to signal how many minutes of deco obligation you have. Then you must ...

Is this the right signal for D? According to this, the sign for D is index finger pointed.
http://en.wikipedia.org/wiki/American_Sign_Language_alphabet

Just wondering if your recommendation is universally known, or something that you and your dive community have come up with.

 

[1_T_Submariner]

Never hit it yet. I have been within 3 minutes but that was close enough on single (120).

Edit:

Oh By the way this thread is being monitored by the Scuba police. If a Black SUV with tinted windows shows up in front of your house and there are big guys with nice suits and sunglasses on (at night). Just give them all of your scuba gear and C-cards.

 

[diver 85]

Okay . . . It's confession time. This came up over the weekend, where my husband did a repetitive dive and racked up what his Mosquito told him was 22 minutes of deco (which is kind of absurd on a dive with a max depth of 90 feet, but where the vast majority of the dive was spent around 50 to 60, but that's what the instrument said). Since it wouldn't give him any credit for time served below 20 feet, he ended up with about a ten minute hang at 10 feet, which he did. Gas was no issue.

Yeah, I know, I know, you shouldn't do decompression diving unless you're deco certified and are diving doubles and have appropriate decompression gases and do your gas management ahead of time. But I suspect that Peter's not the only one who's ever done this. In fact, I know Catherine does deco from time to time.

My question is: Who has deliberately gone into deco on a recreational dive, and how did you figure out how much deco to do? Did you do what your computer asked for? Did it make any sense?

Out of 16 dives in CZM recently(only time out of 900+ dives I had a computer), I deco'ed the VEO I was wearing 3 times- just followed the time @ 10' for the time it told me & made the computer happy, I guess.........lol..............wonder how many other times I've deco'ed without knowing it.........

 

[TSandM]

What's sort of funny about this is that ALL of us did deco on the dive . . . I planned six minutes of deco up from 30 feet (double the shallow stops for repetitive dives) and actually did more, because the contours and sea life were such that spending time at any given shallow depth was just more absolutely delightful diving.

There ARE no non-deco dives. It's just that the system I use gave me six minutes of deco, and the computer Peter dove gave him 22 for a very similar profile. I don't think any of us minded the hang in the shallow, sunlit, relatively warm water, except that by the time I got out, the restroom was looking AWFULLY good . . .

 

[nereas]

What's sort of funny about this is that ALL of us did deco on the dive . . . I planned six minutes of deco up from 30 feet (double the shallow stops for repetitive dives) and actually did more, because the contours and sea life were such that spending time at any given shallow depth was just more absolutely delightful diving.

There ARE no non-deco dives. It's just that the system I use gave me six minutes of deco, and the computer Peter dove gave him 22 for a very similar profile. I don't think any of us minded the hang in the shallow, sunlit, relatively warm water, except that by the time I got out, the restroom was looking AWFULLY good . . .

Yes, this is precisely an advanced notion, that all dives are deco dives.

The manner in which you deco, either by a gradual 30 ft/min ascent or less, and a safety stop, and additional time, and even a pony with deco mix (EAN 50) in it, is a matter of safety and choice.

It is especially amazing to compare software deco plans with USN tables. That gives you a special appreciation for all dives being deco dives, with the deco being relative to the safety you prefer to implement.

That is what the dive computer on your wrist is telling you -- that even though the USN tables of yore say you could ascend even so the modern algorithms are telling you that you need more safety time.

 

[Mo2vation]

So I take it I should plan to use my Oceanic computer while down there ??? I know ... I'll bring 'em both ... if I manage to bend one I'll just toss it in the box and use the other one ...

... Bob (Grateful Diver)

Now you're talking.

Can't wait for your guys. We had some amazing dives out there. More Nudis than I've EVER seen, and I've done a zillion dives there.

Its gonna rock!

---
Ken

 

[DandyDon]

Out of 16 dives in CZM recently(only time out of 900+ dives I had a computer), I've deco'ed the VEO I was wearing 3 times- just followed the time @ 10' for the time it told me & made the computer happy, I guess.........lol..............wonder how many other times I've deco'ed without knowing it.........

The VEO gives suggested safety stops. Do you know the difference between that reading and a Deco Required reading?

I'm not going to try to tell a veteran diver how to dive, but I do encourage newbies to study their manuals and computers until they know them very well - hide the card so you won't try to use it, and run Simulations.

 

[fairybasslet]

The important thing is to understand WHAT the computer is telling you if you should see the numbers. It will usually flash some part of the display ... which is to get your attention that you have gone beyond NDL. It will then display two numbers ... one which is the "ceiling" (usually 10 feet), and one which is the deco time (usually displays where your NDL is typically displayed).

It means ... "don't go above 10 feet until you have stayed there for this many minutes". You should generally, at that point, begin your ascent in an orderly manner. Depending on the computer's algorithm, it may start to credit you with offgassing time after you've reached about 50% of your max depth ... or it may continue accruing deco time until you've reached a relatively shallow depth (20-30 feet). Either way, there are two important things you should do ...

1. Communicate to your buddy that you have a deco obligation ... do this by tapping your computer, holding your hand up with pinkie finger extended (ASL sign for D) and then use your fingers to signal how many minutes of deco obligation you have. Then you must ...

2. Keep a close eye on your available air supply ... running out of air is worse than getting bent. Let your buddy know how much gas you have ... in fact, the two of you should each know how much the other has, because chances are if you're low, so is your buddy.

Do not hurry to your safety stop depth ... unless your gas supply mandates it. If you have sufficient air, remain at safety stop depth until your computer "clears" which means it will go back to the display you're used to seeing at your safety stop depth. Then surface normally .... actually, this would be a very good time to practice surfacing from your safety stop as slowly as possible ...

... Bob (Grateful Diver)

Thanks Bob.

 

[grazie42]

My question is: Who has deliberately gone into deco on a recreational dive, and how did you figure out how much deco to do? Did you do what your computer asked for? Did it make any sense?

Leaving aside the whole definition of recreational diving coupled with deliberately going into deco...

Yes I have. I have a Suunto Vyper, which I like. It doesen´t happen a lot when I dive locally because we tend not to do more than two dives per day but in tropical waters with 3 or 4 dives a day it tends to start getting cranky on the last dives...

I tend to do the time it asks for as long as I know that I haven´t done any of the things I know it dislikes but that I consider "ok"...sometimes I´ll do more...My level of fatigue after a day of diving tells me whether I´ve dived good profiles or bad ones. I tend to feel more refreshed after a day of "technical" dives than "recreational" ones...