Decompression Tables

[Meng_Tze]

...

Why does ANYONE dive Navy Tables?

Machismo, Ignorance, Cyberdiving??? Pick one.

 

[LeadTurn_SD]

Hi Howard.

One of my tanks does still have a J-valve as a matter of fact ... I've never used a horse collar, but would have loved to own one back then.... but I dove "sans" BC when I started

From your avatar (way, way cool by the way!!), I'd have to guess you are taking/accepting much higher risks on any given dive than my very sedentary, typical single Al80, 2-dive, 60'-or-less multilevel shore dives. My biggest risk these days is falling and getting scraped up on the lava when I enter and exit....

Again, I'm not advocating Navy tables or RDP over a current dive computer. I use them or the PADI RDP simply as a backup.... and the majority of my dives can be made without a computer at all.

The OP just asked what folks used. That is what I use.

Best wishes.

 

[HowardE]

Hi Howard.

One of my tanks does still have a J-valve as a matter of fact ... I've never used a horse collar, but would have loved to own one back then.... but I dove "sans" BC when I started

From your avatar (way, way cool by the way!!), I'd have to guess you are taking/accepting much higher risks on any given dive than my very sedentary, typical single Al80, 2-dive, 60'-or-less multilevel shore dives. My biggest risk these days is falling and getting scraped up on the lava when I enter and exit....

Again, I'm not advocating Navy tables or RDP over a current dive computer. I use them or the PADI RDP simply as a backup.... and the majority of my dives can be made without a computer at all.

The OP just asked what folks used. That is what I use.

Best wishes.

I do not take unnecessary risks. I plan my dives, using software. I can print a table out, and run my dive with a bottom timer and the tables I cut. Whether I dive a rebreather or open circuit, I try to minimize the risk of DCS.

So - the decompression tables you use are computer. What kind of computer, and what deco model does it use?

I wasn't necessarily picking on you at first, but seriously... several people have advocated using the Navy table, or the Naui table for deco. Those tables are 30 years old, and really - most if not all modern decompression models implement more stops and starting your decompression deeper, and in general - longer (if you're deco-ing out on Air - which most people don't do anymore).

 

[LeadTurn_SD]

I do not take unnecessary risks. I plan my dives, using software. I can print a table out, and run my dive with a bottom timer and the tables I cut. Whether I dive a rebreather or open circuit, I try to minimize the risk of DCS.

So - the decompression tables you use are computer. What kind of computer, and what deco model does it use?

I wasn't necessarily picking on you at first, but seriously... several people have advocated using the Navy table, or the Naui table for deco. Those tables are 30 years old, and really - most if not all modern decompression models implement more stops and starting your decompression deeper, and in general - longer (if you're deco-ing out on Air - which most people don't do anymore).

Hi again Howard,

I was just messing with you a little But I do envy you your rebreather!

My computer is a no-frills Aeris XR-1. It is based on the Modified Haldanean Algorithm.... but I'm not terribly concerned with it's deco model because I use it mainly as a timer/depth gauge. Reason: My dives are WAY within deco limits.... available gas is always the limiting factor rather than depth, and they are multilevel, usually 40' or less, often single dives.... hardly the stuff that VPM was designed for I'd guess

I agree with you 200% regarding Navy tables for deco. Been there, done that... way back in 1977 at the tender age of 18. I'd never do that again today. There are much better alternatives.

Today, if I was doing the dives I'd guess you and others are doing, I'd probably be using the same apprach you use. But I'm a shallow water wuss these days (gotten older, sigh).

Best wishes.

 

[DCBC]

But I'm a shallow water wuss these days (gotten older, sigh).

Tsk tsk LeadTurn I'm 6 years older than you and recently passed an insurance hyperbaric medical for saturation diving to 1000 ft. Age doesn't necessarily stop you from deep diving. Sorry, but I didn't want people to think that it's a game reserved for the young. In-fact I'd much rather dive with an older guy with the experience.

 

[DCBC]

Great discussion everyone; thanks for your input!

 

[HowardE]

Tsk tsk LeadTurn I'm 6 years older than you and recently passed an insurance hyperbaric medical for saturation diving to 1000 ft. Age doesn't necessarily stop you from deep diving. Sorry, but I didn't want people to think that it's a game reserved for the young. In-fact I'd much rather dive with an older guy with the experience.

I agree... I'm a young guy at 40... and my dive buddy for a few deep dives is 57.

 

[LeadTurn_SD]

Good points guys, thanks (regarding this topic in general, and age). Good topic.

Best wishes.

 

[captain]

Sorry, double post

 

[captain]

Regarding reasons for using Navy tables :

1.) That was what I was trained on in the 70's
2.) Bends risk was/is acceptable if you don't push the limits!
3.) We were informed about the risks when we first started using the tables for the exact reasons mentioned in previous posts, and #2 above was strongly emphasized.
4.) Based on #2 & #3, most of us built in a "buffer" that was more conservative than PADI's current RDP.
5.) Unlike PADI's RDP, we used the Navy tables to plan and execute deep air deco dives. (And no, I would not do that today!)
6.) The Navy tables are based on a square profile, we used them on multilevel dives; so in general my profiles using Navy tables were more conservative than my current dive computer for the same dive.
7.) Now I just refer to them (or PADI RDP) for planning purposes, and carry them in my dive bag "just in case".

Best Wishes.

Exactly. If you use the Navy tables to the NDL limit on one square profile dive the DCS risk is higher than current tables. The thing is we did dives that were not square but multi level but used the deepest depth and next longest time of a square profile but in actuality were nowhere near the NDL. Doing repetitive dives was not an issue because on repetitive dives the Navy repetitive dive tables are more conservative than most current tables.
Now you can say we lost a lot of dive time using Navy tables but you can't say we were less safe.

I first started using the Edge computer in about 1985 and the hardest part was getting past not trusting the computer on repetitive dives because of the experience using the Navy tables. The repetitive dive time were so much longer with the computer compared to the Navy tables.