Dive Computer + Air Integration – Yay or Nay?

[Blackcrusader]

What I'm referring to is, if you do, oh, say, 2 morning dives in a live-aboard, and your dive computer craps out, you may be looking at 2 or 3 more dives that day (2 afternoon, 1 night). But...your body has accumulated nitrogen from your first 2 dives of the day.

1.) Stop diving for the day.
2.) Keep diving (whether applying some educated guess work with tables).
3.) Or the politically incorrect alternative of assuming if he hasn't been hitting NDLs on the usual dive regimen, he'll just take his chances).

1 or 2. Any diver is responsible for their own diving. If their DC craps out then tables are what are used. After all there were no DC's around when I started diving in the 1980's that' s why people still have to learn dive tables. Keep diving and breathe 100% O2 between dives if you are really concerned.

I do not bring a second dive computer on NDL or short deco dives just my Perdix AI and my Cressi Console. Not to say failures cannot happen but I have never had my Perdix or Cressi fail on a dive. For my upcoming TDI advanced nitroc and deco course my Cressi is accepted as a backup to my Perdix AI for the dive. Each dive does require a two devices though that have bottom time and depth. A DC is the preferred device but not mandatory. Square profile deco dives are in any case planned using tables and time and depths for pre dive planning.

 

[drrich2]

If their DC craps out then tables are what are used. After all there were no DC's around when I started diving in the 1980's that' s why people still have to learn dive tables.

From a U.S. perspective, years ago I heard people taking OW courses (PADI, I suspect) were given the choice between a tables or computers version. I was already certified and trained with tables, yes, but my point is, a lot of people did OW training after dive computers were in common use, and I think many of them never learned to use tables.

Even if they did make a mental note of their max. depths from dives 1 and 2 that day, the tables tended to make the diver plan nitrogen loading groups based on the assumption of a square profile dive where the full time was spent at the max. depth. That carried a heavily penalty.

I wonder what % of OW divers certified in the past 10 years in the U.S. ever learned to use tables? I have no idea; sincere question.

 

[Blackcrusader]

From a U.S. perspective, years ago I heard people taking OW courses (PADI, I suspect) were given the choice between a tables or computers version. I was already certified and trained with tables, yes, but my point is, a lot of people did OW training after dive computers were in common use, and I think many of them never learned to use tables.

Even if they did make a mental note of their max. depths from dives 1 and 2 that day, the tables tended to make the diver plan nitrogen loading groups based on the assumption of a square profile dive where the full time was spent at the max. depth. That carried a heavily penalty.

I wonder what % of OW divers certified in the past 10 years in the U.S. ever learned to use tables? I have no idea; sincere question.

How many OW divers are taking LOB trips? Not too many I know some require AOW and Nitrox preferred as a minimum but not all.
Some will offer AOW & nitrox courses on board. I have been offered one LOB for this May that does not have nitrox for their LOB trip.
If your CD fails then using a different DC for dives on the same day would not be accurate for NDL times as the previous dives are not logged. If your DC failed on the second dive you could still do a later afternoon and night dive but just keep to shallower depths.

 

[Blackcrusader]

I wonder what % of OW divers certified in the past 10 years in the U.S. ever learned to use tables? I have no idea; sincere question.

I cannot say. I can say that at a few places I dive with in Asia OW students are taught tables and are given RDP tables and it's part of their course requirement. Although they are given DC's for their course they dive without DC's after they finish their courses. Many OW students don't buy a DC before becoming certified.

 

[drrich2]

Some do, but again from a U.S. perspective, someone certified at the OW level who goes on to get AOW still won't likely encounter tables, and I doubt most of those taking nitrox will, either. For practical purposes, tables don't exist for a lot of fairly recently minted recreational divers.

I can say that at a few places I dive with in Asia OW students are taught tables and are given RDP tables and it's part of their course requirement.

Ah, sounds like this is a regional variation issue. So your suggestions might work well in the area you are accustomed to. In the U.S. and Caribbean, tables are seldom seen where I've dove (in fact, it's practically assumed everyone's diving a computer, from what I can tell).

I don't know what the BSAC or CMAS folks are doing these days with OW level training. Interesting topic, even if tangential to the thread.

Richard.

 

[Blackcrusader]

I don't know what the BSAC or CMAS folks are doing these days with OW level training. Interesting topic, even if tangential to the thread.

Richard.

BSAC tables

Safe diving guide

www.bsac.com

BSAC releases gas density tables

BSAC has released three sets of gas density tables for members. Considered an important source of safety information based on empirical research, the tables are intended to inform planning for safer deeper diving (>40m).

www.bsac.com

 

[GreggS]

I wonder what % of OW divers certified in the past 10 years in the U.S. ever learned to use tables? I have no idea; sincere question.

I can't speak of other agencies but when I did my OW and AOW (both less than 10 years ago) thru SDI. we never even looked at tables although they were provided in our OW kit. They were mentioned as to being how divers used to plan their dives, but SDI advocates using DCs to all trainees now.

 

[Joneill]

How many OW divers are taking LOB trips? Not too many I know some require AOW and Nitrox preferred as a minimum but not all.
Some will offer AOW & nitrox courses on board. I have been offered one LOB for this May that does not have nitrox for their LOB trip.
If your CD fails then using a different DC for dives on the same day would not be accurate for NDL times as the previous dives are not logged. If your DC failed on the second dive you could still do a later afternoon and night dive but just keep to shallower depths.

Exactly why I dive with 2 AI DC's (Perdix AI and Teric) and 2 transmitters - I have to travel to dive (no cold water diving for me) so I don't ever want to have to cut a dive short or miss subsequent dives because of a DC failure. I also carry my old SPG in my bag - just in case.

 

[Joneill]

I can't speak of other agencies but when I did my OW and AOW (both less than 10 years ago) thru SDI. we never even looked at tables although they were provided in our OW kit. They were mentioned as to being how divers used to plan their dives, but SDI advocates using DCs to all trainees now.

I did my PADI OW in 2015 and we did study and were tested on how to use tables as part of the online and in-person class work. My instructor also went over my DC with me to make sure I understood how to set it up and read/use it properly - both in the class/pool and again before we did the 4 OW dives.

 

[doctormike]

I have to travel to dive (no cold water diving for me)

I think I see your problem.