Place of dive tables in modern diving (Split from the basic thread)

[lowviz]

Max Depth vs. Cylinder Capacity


Edit:
You may also wish to read this post in that thread, it is quite informative: Max Depth vs. Cylinder Capacity

 

[tursiops]

Max Depth vs. Cylinder Capacity


Edit:
You may also wish to read this post in that thread, it is quite informative: Max Depth vs. Cylinder Capacity

Well, OK. I guess in the same vein I could say for new divers (as should have been said for this "rule") you shouldn't see an 80 below 60 ft, right? Isn't 60 the max recommended depth for new divers until they get more training/experience?

 

[TMHeimer]

I've use 80s well below 60' and not approached the NDL. But I'm very conservative.

 

[lowviz]

Well, OK. I guess in the same vein I could say for new divers (as should have been said for this "rule") you shouldn't see an 80 below 60 ft, right? Isn't 60 the max recommended depth for new divers until they get more training/experience?

The whole intent was to make first order (SIMPLE) approximations to the big three: Depth, Time, and Gas.

As an OW newbie, I was creeped out if I exceeded:

1) Diving deeper than my tank
2) Staying at planned depth longer than the 120 rule
3) Starting my ascent (following the buddy system) with less than Depth in ft x 10 + 300 psi

As I progressed in time and experience my 'rules' became more aggressive and harder to remember.

 

[boulderjohn]

AL 80s are commonly taken past 80 feet. Just because some people don't think it is a good idea does not make it a rule for everyone. I have taken AL 80s past 80 feet and ended up with an 80 minute dive.

Work it out: 100 ft is 4 ATM, so a SAC of 0.7 cuft/min (not a great SAC, by the way) means 2.8 cu ft/min at 100 ft. So NDL is 20 mins on Navy tables, 12-16 on other tables

US Navy tables NDL at 100 feet is 25 minutes. For PADI it is 20 minutes.

 

[BenjaminF]

Oh no, I’m sure there are people out there that could bend themselves with an 80 no problem.

This is one statement that you don't want a reaction of "challenge accepted!"

 

[The Chairman]

Pete... You saying that you... MAKE up your own safety stop times and your own way of off gassing without any specific table or computer model ?

No. Not really. When PDCs first started being popular, the agency I was teaching for told us to extend our safety stops to five minutes. I'm just opting to do the longer of the two.

 

[lowviz]

AL 80s are commonly taken past 80 feet. ...//...

Of course they are.

I mentally shifted gears to "OW think" after the mod warning bell on this thread.

I probably should have better signaled that. This thread would be better served in Advanced. [/OPINION]

 

[tursiops]

AL 80s are commonly taken past 80 feet. Just because some people don't think it is a good idea does not make it a rule for everyone. I have taken AL 80s past 80 feet and ended up with an 80 minute dive.

US Navy tables NDL at 100 feet is 25 minutes. For PADI it is 20 minutes.

Oops, yes, I grabbed the 110ft numbers. Tables may be perfect, but their operators are not.

 

[jlcnuke]

I took the OW course twice, more than a decade apart. In neither case did any "80" rule come up at all. That a small group of people think it's a "rule" or a "good idea" for "some divers only" to follow doesn't make it a rule that people know, care about, or follow. I've certainly not followed it (having never heard of it until today) and have no plans to. I don't know anyone else that's followed it either (including the guy who did his OW cert on my last liveaboard, with an AL80, who went well below 80' with it that same week). None of the crew (all but 1 or 2 I'm certain were qualified dive instructors) ever mentioned it to my knowledge either.

I looked at the links mentioned earlier and I can't see anything this rule prevents realistically if the basics from the OW course are followed (don't exceed NDLs and don't run out of gas for instance). A diver that does OW and then AOW immediately after is still going to be safe if they follow their NDLs and surface with adequate air remaining regardless of what size tank they took to >80'.