Going into deco

[Walter]

you shouldn't do decompression diving unless you're deco certified ....................

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?

Lynne,

I've planned and conducted lots of staged decompression dives. Is there a "decompression" certification? I've never heard of that one, but all kinds of agencies are always coming up with lots of odd ball certifications, so I probably just missed it. As for following my computer, when I first started making staged decompression dives, no one had computers. I followed the US Navy tables and added stops and extra time at each stop. Once I started diving with a computer, I still planned staged decompression dives with tables. I'd take my Edge on the dive, but I didn't rely on it. Now, I add stops and extra time to the stops required by my computer. Did what make any sense, Darlin'?

 

[DandyDon]

We were fine, had a good long dive. Computer was miffed. So what? The dive rocked.

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)

Ignoring computer warnings does not sound as safe as diving a computer you respect....? :shakehead

 

[Sharky1948]

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)

Just take a bottom timer and "remember" the tables as you see fit.

 

[Walter]

Don,

Sometimes computers fail. I remember one dive on which I was diving with two computers, one more liberal than the other. I planned to follow my conservative computer and add in some fudge factors which is exactly what I did. The conservative computer gave me about 10 minutes of deco, but the more liberal computer started showing close to an hour of deco. My three buddies all had deco obligation on the order of 10 minutes showing on their computers. I tossed the malfunctioning computer in my luggage and stayed with the other one for the rest of the trip. While, in general, I don't recommend Bob's tongue in cheek approach, there are times it is appropriate.

 

[Blitz]

I have a bottom timer and a vytec. The vytec only gets used so I can download the profile..... and because it gives me a chuckle to bend it when I dive Helium with deco gas.

 

[Gene_Hobbs]

diving a computer you respect.

Is there such a thing?

While on the topic...

Proceedings of Reverse Dive Profiles Workshop.
Lang and Lehner (eds) 2000. Proceedings of Reverse Dive Profiles Workshop. American Academy of Underwater Sciences. 295p.
RRR ID: 4244

FINDINGS: 1. Historically neither the U.S. Navy nor the commercial sector have prohibited reverse dive profiles. 2. Reverse dive profiles are being performed in recreational, scientific, commercial, and military diving. 3. The prohibition of reverse dive profiles by recreational training organizations cannot be traced to any definite diving experience that indicates and increased risk of DCS. 4. No convincing evidence was presented that reverse dive profiles within the no-decompression limits lead to a measurable increase in the risk of DCS. CONCLUSIONS: We find no reason for the diving communities to prohibit reverse dive profiles for no-decompression dives less than 40 msw (130 fsw) and depth differentials less than 12 msw (40 fsw).

 

[fairybasslet]

I never had a deco obligation and now...for the confession part, I'm not sure I would be able to read it on my computer if I did. I have an Uwatec. Would it tell me, 10 minutes at 20 feet or something like that? I have no clue. I've occasionally thought about the fact that I don't know what the computer will look like during a deco obligation, but never thought to try it out or ask someone, or look in the manual.

 

[MXGratefulDiver]

I'm becoming more and more one of those ratio deco heretics ... after running a coupla dozen dive profiles on V-planner (VPM) and doing the ratio deco math on the same profiles, I saw enough of a pattern to have some confidence in my ability to decide on my own what my ascent rate should be for a given dive. All I really need from the dive computer is depth and time.

I'm generally more conservative than the computer anyway ... even on a planned deco dive. And like Walter said, I don't generally recommend Bob's tongue in cheek approach either ... but there are times when it's appropriate.

... Bob (Grateful Diver)

 

[Web Monkey]

my understanding is that if you have a too-quick ascent for any length of time on a 1st dive, the suunto software penalizes you on the 2nd dive. The amount of penalty is (supposedly, I don't have one of these computers) dependent on the surface interval time. So, with a momentary fast ascent and a shortened surface interval, even a relatively shallow 2nd dive can be problematic for the computer if it goes deep late in the dive or has multiple ups and downs.

That's interesting and might explain how my buddy came up with 20 minutes of deco while I had none on the same dive. She did a pretty quick ascent from 15' on the previous dive.

Terry

 

[DeepBound]

Is there a "decompression" certification? I've never heard of that one, but all kinds of agencies are always coming up with lots of odd ball certifications, so I probably just missed it.

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