Recreational Scuba Deco Diving

[Edward3c]

@rx7diver

1. Often
2. Both
3. Both
4. Buddy
5. Single with pony or a 50% deco gas.
6. I plan the profile then dive it, whether that involves mandatory deco or not.
7. Leisure, anything else is classed as commercial in the UK (including Artifact hunting, Scientific/research, Teaching diving for reward (PADI etc)).

The term ‘technical’ is just a marketing term to increase the number of income streams.

 

[Miyaru]

Crossing the NDL is not a big deal. Anyone can do it. Those who do, usually ride their computers.
Extending the NDL is what most divers do with nitrox.

Fixing problems when you're beyond the NDL requires time.
And when you're posting here, after getting into trouble beyond the NDL, you obviously had that time. Those who lacked time, won't post about it. Because the replies would probably contain words like stupidity.

 

[Rollin]

1. Often
2. Both shore diving, boat diving
3. Marine
4. solo diving/ buddy diving 50/50
5. Back-mounted isolation-manifolded doubles on air (no eanx where I dive often)
6. No plan, riding my DC, gas calculations on the fly (with margin).
7. Video and photo

I'm qualified to do extended deco, even on 100%. But I almost never bother. Gas consumption is around 10l/m and with double 10l tanks, dive time is more than long enough.

 

[rx7diver]

Hmmm. This thread isn't going the way I had hoped. There have been only a relative handful of posts that address my OP. I was/am hoping to learn how prevalent RSDD-type diving is, and how people who do it, do it.

In my own case, I didn't begin decompression diving until I moved to the Great Lakes region of the US (in the early 1990's) and began diving the shipwrecks there. Almost immediately came the purchase of a drysuit, followed by extended range diving initially with 100% oxygen accelerated decompression and, later, with both EANx and oxygen deco gases on a single dive.

Everyone I was diving with was learning to do things this way. The primary motivations were two, I think: First, to exit that extremely cold water (Great Lakes Huron, Michigan, and, especially, Superior) as quickly as safely possible. And, second, to surface as quickly from a deep dive as safely possible because the Great Lakes can turn seriously disagreeable very quickly!

I wonder, though, if I had begun deco diving somewhere else (where the water was not so cold and the seas were less likely to turn violent without a moment's notice), if I would simply have chosen to pursue a RSDD approach.

I was/am hoping to learn if other divers are RSDD diving whenever they don't "need" to approach things using a more complicated/involved approach, and if they are, how exactly they are doing their RSDD diving.

rx7diver

 

[tursiops]

Hmmm. This thread isn't going the way I had hoped. There have been only a relative handful of posts that address my OP. I was/am hoping to learn how prevalent RSDD-type diving is, and how people who do it, do it.

You seem to be learning, instead, that people do not generally think it is a good idea, and that it is mostly done by the untrained or those trained a long time ago or those that can't be bothered to take input that may save their butts.

 

[Angelo Farina]

This was for me the standard way of diving since when I started (1975) until when I got too old (2010) and converted to low-effort, small depth diving.
Here my answers:
1. Often. Some years it was more than 200 dives. Some others "just" 60 or 70...
2. Boat. Usually a small inflatable (Zodiac or the like). I do not like shore diving, too fatiguing. And I do not like a boat of which I am not the captain.
3. Marine (Mediterranean sea, where the best is below 40 meters) - being deep dives only with air, never used Nitrox for deco recreational dives.
4. Buddy always (I am not certified for solo, and always found it dangerous). My wife is my permanent buddy since 1977. It was like diving together with a siren, a pleasure by itself, even if the site had nothing to be seen. Later on, also our sons became our dive buddies, of course.
5. Initially, in the seventies and eighties, it was a twin 10+10 liters. The standard twin-tank used since the first course, with two valves and two independent regs. Starting around 1985 I switched to a 15-liters steel single, again with two valves and two fully independent regs. I never used a tank with just one valve, I find it quite unsafe.
6. Exposures you typically plan for: usually max depth was known, bottom time was planned in a range (say 15 to 25 minutes at 50m - the choice when ending the dive was usually driven by the amount of air remaining), and the duration of the required deco stops was evaluated after reaching the first stop (using tables).
7. Typical activity: Photography, Video, archeological artifact hunting.

 

[boulderjohn]

Hmmm. This thread isn't going the way I had hoped. There have been only a relative handful of posts that address my OP. I was/am hoping to learn how prevalent RSDD-type diving is, and how people who do it, do it.

This may relate in part to something I posted in another thread a few days ago, which I will explain after an anecdote.

A few years ago I made a post about my practice using my Shearwater computers while on recreational dives. I noted that when I did a recreational dive, I left the computer in technical dive mode and never bothered to change the settings (gradient factors), and those settings were much more conservative than is typical for recreational diving. As a result, I went into deco before the others with whom I was diving. Because I understand how those things work and have other settings on those computers to guide me, I pretty much ignored the fact that I was in deco and completed the dive with my buddies. I knew that I was only in deco because I had not bothered to take the minute or so I would have needed to change the settings to those more typical of recreational diving.

Man, was that a mistake! A former SB regular, whose primary purpose for posting on SB seemed to be to make my life Hell, started an entire new thread to attack me for advocating unsafe diving by telling people that it is OK to ignore deco limits on recreational dives. He started a new thread so that they people reading it would have only his description of what I had written to go on; they did not see what I had actually written. I did not discover the thread for 3 days, during which time people generally agreed that I was a total SOB for advocating such dangerous practices. When I found the thread, I linked to my original post, and people who posted after that said, "Oh! That is different! Never mind!" However, I am sure many people who participated earlier never returned to the thread and never saw what I wrote.

As a result, I now do change the settings so that I do not go into deco super early, just so anyone seeing ti does not freak out like that.

In the post I referenced earlier, I said that a lot of highly experienced and highly trained divers are reluctant to describe personal practices that are borderline over the edge, and that is why.

 

[Searcaigh]

My regular diving generally has a first dive to 28-30m, with regards to deco obligations;

1. Occasionally
2. Boat diving
3. Salt water
4. Buddy diving
5. Single AL80 or Steel 12L backgas (EAN34) with AL30 for deco (EAN50)
6. Planned 30-40 min bottom time depending on what the objective is.
7. Photography.

 

[rjack321]

I was/am hoping to learn if other divers are RSDD diving whenever they don't "need" to approach things using a more complicated/involved approach, and if they are, how exactly they are doing their RSDD diving.

Most recreational divers are taught to avoid deco - and even in the agencies that do teach "light easy backgas deco" (tm) its not part of their OW and AOW curricula.

There are actual decompression courses that teach you this stuff so you don't have to wing it. Once you have access to higher fO2 mixes doing a 7 minute bottom time kind of dive at 150ft because you only have a modest amount of gas in your single cylinder starts to seem pretty silly. So the course gives you access to the proper tools and mindset, and you're surprised that people take advantage of that.

Maybe you should take or retake AN/DP or NAUI Tech1 or GUE tech 1 or PADI tech40 or one of these entry level deco courses. You'll probably learn more than via a scubaboard thread.

 

[rx7diver]

This may relate in part to something I posted in another thread a few days ago, which I will explain after an anecdote. ... In the post I referenced earlier, I said that a lot of highly experienced and highly trained divers are reluctant to describe personal practices that are borderline over the edge, and that is why.

Thanks, @boulderjohn. This hadn't occurred to me. Yes, this can explain why more people aren't responding. I suspect that many people on here are doing RSDD diving--even though the posts in this thread are not corroborating my suspicions.

Regarding my own diving: When I returned to mid-Missouri (from SE Michigan) in the late 1990's, where there still remains no easy access to nitrox and oxygen fills, I decided to try to approach my deco diving in a different way, in a RSDD way: I first used only my air-filled isolation-manifolded double HP 120's (no pony/bailout/deco cylinder).

But then, since I was diving solo, I decided that using my HP 120's as air-filled back-mounted independent doubles (still without pony/bailout/deco cylinder), was a safer RSDD approach for me. I was making shore dives in Army Corps of Engineers lakes in SW Missouri and NW Arkansas.

HP 120's are overkill for me for this type of diving, but this RSDD approach (i.e., using air-filled back-mounted independent doubles) turns out to be the perfect approach (for me).

However, I began my family in 2001, and shortly after that I ceased doing deep/deco dives altogether.

rx7diver