Buying my first Dive Computer need a little help

[stuartv]

BSAC on their Ocean Diver (equivalent to OW + AOW) teach tables that include Decompression areas for calculations, and then Sports Diver (think of it a Advanced AOW & Rescue) teach Planned decompression on a single gas. You can then get an additional qual of Accelerated Decompression (which I surmise but don't know would be similar to AN/DP) so as a rec diver under BSAC you do get involved with Mixed gas.

Personally, I would no longer consider that to be recreational (i.e. recreational sport) diving. I would term that (any diving involving planned decompression) technical diving.

 

[dmaziuk]

There's a murky area where e.g. BSAC considers 50m recreational depth whereas my recreational computer's stated "algorithm depth" is 40m whereas some other tables go to 60. Or if you overstay your computer's idea of NDL because you know this "other algorithm" considers this couple of minutes perfectly OK... does it make it "planned decompression" if you know in advance this may happen on a particular dive. And so on.

 

[stuartv]

To me, it doesn't matter how you plan it. If your plan is by computer or tables, and it includes a deco stop, then it's a tech dive. If it's a NDL dive in open water (i.e. No overhead, real or virtual), then it's a rec dive.

 

[KeithG]

To me, it doesn't matter how you plan it. If your plan is by computer or tables, and it includes a deco stop, then it's a tech dive. If it's a NDL dive in open water (i.e. No overhead, real or virtual), then it's a rec dive.

I agree. No overhead is a significant key.

In the old days they called it "no stop" diving. Theory was that you could go directly to the surface any time you wanted (non of this optional but highly mandatory-ish safety stop stuff). "Do not pass Go. Do not collect $200" diving was forbidden for us OW peeps. You could go to the surface at any time you wanted.

Back then, we had people pushing the edges of the tables. Now we seem to have people riding the NDLs of their computer and looking for less conservative (more aggressive!) algorithms / settings. And then wondering why they get bent?

 

[scubadada]

I agree. No overhead is a significant key.

In the old days they called it "no stop" diving. Theory was that you could go directly to the surface any time you wanted (non of this optional but highly mandatory-ish safety stop stuff). "Do not pass Go. Do not collect $200" diving was forbidden for us OW peeps. You could go to the surface at any time you wanted.

Back then, we had people pushing the edges of the tables. Now we seem to have people riding the NDLs of their computer and looking for less conservative (more aggressive!) algorithms / settings. And then wondering why they get bent?

I believe that all of the commercially available decompression algorithms are safe when observed for rec diving. There is no data to suggest there is a difference in the rates of DCS. I was hoping that DAN's Project Dive Exploration might shed some light on this topic, it still may with the expanded database. DAN website suggests results are forthcoming.

On the other hand, there are significant differences in individuals and susceptibility to DCS. Unexplained (previously, undeserved) episodes of DCS occur with all brands of computers and decompression algorithms. Choice of a more conservative or a more liberal computer is a personal decision, but at least, should be an informed one.

 

[Diving Dubai]

I couldn't agree more. This is why I get so irritated when people take a simplistic approach, i.e. this brand is too conservative and this brand is more liberal.

How many people I wonder take into account other factors like:

Are you a fit 20s or a slightly overweight middle age person
Do you dive regularly or occasionally
Are you diving warm or cold water? - I didn't realise until @DevonDiver posted an article that warm water divers could be more predisposed to a DCS


The two times I've witnessed a DCS the overriding factor has been dehydration, both in warm climates, with people underestimating the effects of heat and humidity.

 

[dmaziuk]

My favourite so far is this: Gender differences in circulating bubble production after SCUBA diving. - PubMed - NCBI -- I wanna be a girl when I dive.

 

[stuartv]

Back then, we had people pushing the edges of the tables. Now we seem to have people riding the NDLs of their computer and looking for less conservative (more aggressive!) algorithms / settings. And then wondering why they get bent?

Since all the recreational computers are, I believe, more conservative than the PADI RDP tables, why do you imply that people riding the NDL on their computers is being more aggressive than how people behaved "back then"?

 

[scubadada]

Since all the recreational computers are, I believe, more conservative than the PADI RDP tables, why do you imply that people riding the NDL on their computers is being more aggressive than how people behaved "back then"?

DSAT is essentially the PADI RDP for computers

 

[RainPilot]

Since all the recreational computers are, I believe, more conservative than the PADI RDP tables, why do you imply that people riding the NDL on their computers is being more aggressive than how people behaved "back then"?

Hey Stuart. I suspect its because with tables, the whole dive was at max depth. I used to get out, check the time and the indicator needle on my depth gauge and use that to work out my repetitive dive times. Since none of my dives were ever square profile, almost always ascending during the dive, I for one was a LOT more conservative then than I am now where I actually end up riding the NDL.

I know a lot of divers that get to NDL-1 then ascend a little up the reef and repeat till gas gone or surfaced. While that is not unsafe as far as Im concerned, it is definitely more aggressive than if you calculated the same dive on regular tables.