Place of dive tables in modern diving

[BRT]

When your dive computer batteries fail you have lost your electronic brains....
If you want to continue diving during that once in a life time vacation to a far away tropical paradise

You can use the old fashioned dive tables --- If you have a set and know how to use the dive tables

SDM

You cannot use the dive tables to continue diving if your current dive data shows you are deep in decompression by the tables.

 

[agilis]

Hey, thanks for the disdain... in 38 years since certification, I take ONE dive specific holiday and I get grief like I am a drunken scuba bum. What if I said I was volunteering on an Agean wreck excavation or doing a reef study? That would not make the tables more precise or the computer less useful. And sure you could set a computer to its most liberal settings and dive the tables more safely, but why?

If you are not comfortable with the computer calculating everything for you and giving you a safe multi dive profile, why would set it at its most liberal settings? Don’t dive out of your comfort zone.

I said understanding the tables are valuable. If you are going to go near or beyond the NDL, you need to PLAN and have reliable back up bth in gas and a way to measure depth and time. For a lot of divers that means two computers or a watch and depth gauge. Those are a belt and suspenders situation.

Other than diving, I have absolutely NO PLANS. I would invite you along, but sadly the trip is full....

I'm not sure where you found distain in my post, but apologize for anything you found objectionable. I honestly thought I was making it clear that I'm not as zealous a diver as many other people, and that I don't do more than two dives in a day, one more often than not. I don't enjoy being in a group of divers on vacation. I find herpetologists, ichthyologists, and birders more interesting, perhaps because their experiences are more varied and unique.

I have a computer and I use it when appropriate. On a single dive to 80 feet all I need is a watch , a depth gauge, and an spg. I take the computer with me, and use whatever parameters are most conservative, especially during safety stops. I tend to calculate based on square profiles, though not always. On sawtooth profiles I use my very conservative computer, but I'm always aware of what the tables would indicate.. I'm not anti-computer, but I do think divers should know how to use the tables and understand the physiological basis that informs them. If the tables and the computer differ a diver should be immediately aware of any discrepancy and undertake determining why it exists.

I'm not sure what you meant to suggest with your Aegean plans, but I hope they are not charging you anything for the volunteer experience, the same with your reef study. Thanks for the abortive invite. I appreciate the thought.

 

[BRT]

Do the tables and the computer ever differ?

 

[lowviz]

...//... Dive how you enjoy, but tables are much more restrictive than the computers and far less precise....

Well, yah.

Most first approximations are exactly that. But tables do, IMHO, aid in understanding. DCs are inscrutable unless you are a programmer and want to pick apart some of the open source code that is easily found on the internet. Much too much trouble.

I dive a PDC while mentally comparing what it allows me to what I would have been limited to by US Navy tables. If I'm starting to get way too much extra time, I call it. Probably means that I'm screwing around too much with respect to depth.

 

[KeithG]

Well, yah.

Most first approximations are exactly that. But tables do, IMHO, aid in understanding. DCs are inscrutable unless you are a programmer and want to pick apart some of the open source code that is easily found on the internet. Much too much trouble.

I dive a PDC while mentally comparing what it allows me to what I would have been limited to by US Navy tables. If I starting to get way too much extra time, I call it. Probably means that I'm screwing around too much with respect to depth.

Which part of the tables helps you? The list of depths and NDLs? Or the crazy remember your group , flip it, over follow the column and the make sure you add the right numbers together part?

And once again you are confusing deco algorithms with NDL limits. There is never any need to look at dive computer source code. You just flip into plan mode and it will tell you the NDL limits. Just like if you looked at one corner of your tables. Except it will not let you forget or lie about your prior dive profiles and your SI.

 

[lowviz]

Which part of the tables helps you? The list of depths and NDLs? ...//...

Yes, that.

I can't accidentally change conservatism or gas mixes when using tables. Simple sanity check. Nothing more.

Yes, I could do it on plan mode, but what it gives me is based on the same error.

 

[agilis]

Do the tables and the computer ever differ?

Sure, almost all the time.

 

[BRT]

Sure, almost all the time.

Yeah, mine never match either. So I use the computer. If you are going to follow the tables why own the computer?

 

[KeithG]

Yes, that.

I can't accidentally change conservatism or gas mixes when using tables. Simple sanity check. Nothing more.
.

So if all you are using is the list of NDLs then you really are not "using" tables. You are using a trivial part of the tables. The part that will be wrong for your second dive of the day...

The computer plan mode will correctly adjust that list of NDLs for your second dive.

 

[TMHeimer]

You cannot use the dive tables to continue diving if your current dive data shows you are deep in decompression by the tables.

Yes, but as I mentioned, you probably don't have that problem with square profiles.
Another way to look at the old "tables vs. computers" thing is that knowledge of tables COULD help. Like most knowledge, at least it can't hurt.