Going into deco

[rockjock3]

TDI has a course called "Decompression Procedures", which is separate from the advanced nitrox. So, yes, there is such a thing

Naui also has "Decompression technique" in its technical curriculum.

 

[rockjock3]

repeat post

 

[rockjock3]

If you're lucky you can get the exclamation point, if not you'll get full error and it'll refuse to dive for a day or two afterwards. Got caught out with this when i entered my mix during a food break, took too long diving it, it reset to air due to time period and i forgot to check. Bent it.

Mine bends everytime I do staged deco and still lets me dive the next day. It is only gauge mode, but that is all I use it for anyways (suunto mosquito). I only use it as a tool with my tables and common sense.

 

[drbill]

I have gone into "unplanned" deco numerous times which does not bother me. Given my focus on videography, I rarely can "plan" a dive based on what I expect to see... Nature just happens at unpredictable depths.

I try to use the obligatory deco indicated on my Aladdin Pro as a guide to the MINIMUM deco time. Usually I will double or triple it to determine my personal deco time. Occasionally I will increase it ten fold if gas and conditions permit.

 

[lamont]

OK, since I'm the one who "did the crime so I did the time" I want to give the other side of the story.

First of all, my team had discussed the possibility (probability!) that we would "go into deco" per my Suunto on both dives -- which we did. We also had planned on doing minimum deco profiles on both dives -- which I believe we did.

Second, after discussing the "possibility" of going into deco, we discussed the issue of having enough gas -- and we decided that wasn't an issue.

Third, and last, since both dives were rocking, we decided to "do the crime" with the (correct) belief that we'd do enough shallow to clear any obligation. Yes, we deliberately went into "an overhead environment" without doubles, but the team had plenty of gas.

Here are the profiles of both dives:

Dive One -- I surfaced with 600+ PSI or about 24 Ft3 remaining.

Dive Two -- I surfaced with 600+ PSI or about 24 Ft3 remaining.

I loved the time I spent hanging -- did some drills with HBDivegirl, looked at the Garibaldi, had a wonderful time.

TSandM just said, these dives are a perfect example of why new divers shouldn't have big tanks!

unless i'm missing something those profiles look fine. dive #1 is actually the more concerning but it was minimal amounts of mandatory decompression and deco on 130s is about 400 psi / 10 min for 2 divers breathing fairly heavy, and peter had that leftover after doing his deco. with an 800 psi rock bottom at 80 fsw, peter had 400 psi over rock bottom which is 10 mins of deco for 2 people. that's about right.

dive #2 the suunto was just being *****y about dive #1. there's no reason for that dive to have generated 22 minutes of decompression...

 

[HBDiveGirl]

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 . . .

My Rasta-mon Atmos II was totally chillin' on all of these dives! I had no deco obligation at all, and guided the dive along the beautiful slowly rising slope that Lynne described because I know those slow ascents from 40fsw make me feel better after diving.

I don't have a print out of our profile, but I remember these details:
Dive #1: 32%. no deco obligation. Max 100fsw. Slow rolling ascent from 50. Never less than 10 minutes remaining bottom time

Dive #2: 21%. no deco obligation. Max 87 fsw. My Easy-Going Cabana-boy computer actually did lean forward from its lounge chair at about 67fsw and look over its sunglasses at me, suggesting I should head upwards within the next 5 minutes. It settled back comfortably when I rolled us up to 50fsw for a couple of minutes, and then up to 40fsw. At that point, it turned the reggae music back up and said, "'Tain't no ting, baby... enjoy yo'self in dis beautiful world." We dawdled happily from 40 to 22fsw, where Lynne and I met up with the other team (Ken, Peter, Jaye). Peter joined our team, and we accepted his invitation for a lovely, sun-filled hang at 18fsw, where I remember completely owning him at Rock/Paper/Scissors ... as the Garibaldis, half-moons, blacksmiths, and senoritas flitted about us in the clear water. Then Peter removed his mask and handed it to me.... while he hung in complete relaxation as the gentle surge swung us back and forth. He just hung there breathing, touching nothing. Sweet. He got his mask back on and cleared it. We did an S-drill. Vyper-Deco satisfied, we split for lunch at the Dockside.

Great dive.

No deco here, mon!

~~~~~~
Claudette

 

[Walter]

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

One is either diving professionally or recreationally.

 

[Diver Dennis]

The longest deco I've done was on airs dives to the San Francisco Maru in Truk. I had 22 and 24 minutes of bottom time and I think I did 53 minutes on the longest one. We were diving 110 singles but did bring an extra 80 with regs. Actually Catherine has a picture of this dive and I do too... somewhere. This was using Suunto computers and they were both within a minute of each other. Not an uncommon dive for Truk.

Going into deco is not a big deal for me since it is usually on a multi-level dive and I'm clear before my safety stop.

 

[Kevrumbo]

This was one of my Chuuk Lagoon Profiles on Air Mix (and I don't remember much about the dive because of the extreme narcosis):

(2004 Truk Odyssey Liveaboard Trip, old San Francisco Maru Dive Profile now re-calculated w/ Ratio Deco):

190' for 20min. Air mix w/ eanx50% Deco Gas
Ratio Deco 1:1, 20min. Deco Time plus 20min Set Point Adjustment equals 40min. Total Deco on 50%

190 20min.

180 to 120 ascend 30fpm

110 1min.
100 2
90 2
80 2
70 5 50% switch
60 5
50 3
40 3
30 4
20 10
10 -> or from 20' to surface @2fpm (10min.)

Need: Dbls AL80's, Stage Bottle AL80 w/ Air Mix,
Deco Bottle AL80 w/ eanx50%; and an X-Scooter.

I've gone totally to the Dark Side: I use my Vytec exclusively in Gauge Mode only, and in Metric Units as well !!! . . .perfectly comfortable utilizing Minimum Deco/Ratio Deco for initial Gas & Profile planning, and for real time on-the-fly contingencies.

 

[miketsp]

..snip..

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.
..snip..

Tabus around deco diving are very much an American hang-up probably due to the certifying agencies based there and their fear of litigation. Interesting to note that my PADI & SSI tables stop at 39m while my CMAS tables cover both longer dives with more stops and dives to 63m. It's probably also a commercial thing because by imposing limits there is room to sell a lot more courses.

There are places I visit with a lot of wrecks in the 30-40m range where deco diving according to the tables (nice square profiles) and on singles is absolutely routine and I've never heard of any incidents. Most of my friends in the UK regularly dive deco. Attitudes seem to be a little different on the other side of the Atlantic.