Place of dive tables in modern diving

[AfterDark]

If we were talking the third or fourth dive? First dive is easy, more surface intervals second dive.... you need to track your dives, computer or old school. Set computer in gauge mode and it will work like a bottom timer depth gauge. Collects exact same data, you don’t get any handy dandy calculations. Of course if you are running tables in your head you never set off your spouses computer, you are going to massively over compensate. Round to the next highest everything. What you will do is have much longer SI and much shorter bottom times

If we're talking 3 or 4th dives we're talking shorter BT / longer SI times, with or without a PDC. Any diver with the amount of experience and dives you have knows their air consumption well enough to use it as a indicator of time at a given depth. I know because it was exactly what I did pre-PDC dives when I forget to set/check my watch.
Even depth can be approximated closely enough if one knows the site well enough.
Like OldSchool the use of tables for decades transforms a diver into their own PDC to a degree.

 

[CT-Rich]

You say that like it is a bad thing.

In my current medically compromised (temporary) state, I find that I have been diving less but enjoying it much more.

Forces one to really plan a "cookie" dive and enjoy it. I am surprised at how much I now enjoy those. If I live long enough, I think that I will finally figure out this 'diving thing'.

I much prefer choosing to relax on the waters edge than being beached unnecessarily.. Reducing task load while giving me more bottom time and adding safety all come out of PDC use. Why wouldn’t I embrace that? MOST divers are going to stay within the NDL because of air consumption, at least on dive one. The math is easy and a computer is a fun accessory. But after that, you get freedom, a real time graphic display about where you are in relation to the NDL and you can choose to walk as close to that line as you want (yes the computer is only giving you an approximation, but it is based on very real data).

I am sure there are a few engineers who look with disdain at calculators and remember whistfully about how you get a better feeling for load calculations doing them long had with a slide rule (I bet those were all dead by 1985).

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

 

[oldschoolto]

3 - 4 - 5 dives a day? Two a day with a nice nap and food is how I dive now.. I guess it would have been nice to have a PDC back in the day..

And, I never thought I'd see the day that someone would call navy tables conservative.. LoL..

Jim...

 

[RayfromTX]

The devil is in the details and so is the angel of mercy.

All discussion of deco, PDCs and tables in a thread like this are so limited by the format that we are just taking nibbles around the edges because of the number of qualifying factors with any position statement. Almost any opinion expressed here will be surrounded by a bunch of "yes buts". I still find it interesting but for those that are new to diving,(this thread is in basic scuba) we must realize that most of this makes sense because of a substantial learning curve that backs up what we are reading and if any experienced members want to help those new members not be lead down a risky path, it will be hard for it not to sound like an argument.

Still it is better that this thread got split off from the original thread that was a question about a new dive computer recommendation. Dive safe and read lots y'all.

 

[CT-Rich]

With all the rounding up and basing all calculations on max depth, a lot of conservativism gets built into the dive plan (unless you actually dive a true square plan or choose not to include that conservatism). With any diving you are going to build in a comfort margin. Just like with nitrox you can decide if you are going plan on a max PO2 of 1.6 or 1.4. You choose where you set your personal limit.

3-5 dives a day? I have vacation on the brain.... going to Gran Cayman in a couple of weeks. But that is where I expect to get best value out of a computer. How precise would my nitrogen load be on a computer versus tables? Tables will send me to the bar when a computer will send me on a night dive.

Virtually none of my summertime shore diving requires any gauges other than an SPG. Two dives in a day above 60’ usually around an hour each, lunch in between... I like having the data for my log book, but I don’t really need that for anything either.

 

[lowviz]

The devil is in the details and so is the angel of mercy.

...//... I still find it interesting but for those that are new to diving,(this thread is in basic scuba) we must realize that most of this makes sense because of a substantial learning curve that backs up what we are reading and if any experienced members want to help those new members not be lead down a risky path...

I'm glad someone explicitly pointed this out. Much of what I coulda/woulda/shoulda said never made it to the keyboard as this thread is in Basics.

I read the OP as asking the question "Do tables have ANY value at all anymore for anything?" For some divers, myself included, they do indeed. But having said that, almost all of those who believe tables still hold value, routinely dive a computer.

@oldschoolto: I would be willing to do my two, maybe three dives using USN Table 5 and Table 4 for repetitive dives and feel safer than if I were to aggressively fly my dive computer if set to most liberal. I bet I could rash myself and not hear a peep from it...

 

[Sam Miller III]

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

 

[agilis]

With all the rounding up and basing all calculations on max depth, a lot of conservativism gets built into the dive plan (unless you actually dive a true square plan or choose not to include that conservatism). With any diving you are going to build in a comfort margin. Just like with nitrox you can decide if you are going plan on a max PO2 of 1.6 or 1.4. You choose where you set your personal limit.

3-5 dives a day? I have vacation on the brain.... going to Gran Cayman in a couple of weeks. But that is where I expect to get best value out of a computer. How precise would my nitrogen load be on a computer versus tables? Tables will send me to the bar when a computer will send me on a night dive.

Virtually none of my summertime shore diving requires any gauges other than an SPG. Two dives in a day above 60’ usually around an hour each, lunch in between... I like having the data for my log book, but I don’t really need that for anything either.

A vacation for me is only partly for diving. I enjoy the unspoiled tropics as much out of the water as in it, so I don't go to places where there is not much to do beside diving anymore. Dominica and similar places where the above water natural world is as seductive and beautiful as the reefs have become my vacation spots. A one or two tank dive in the morning is perfectly adequate for me, with the rest of the day spent exploring the rain forest. Some days I'll skip diving altogether for a hike into the interior to see boiling lakes or long abandoned manor houses, or for an hours long snorkel trip along some intriguing shoreline. I always rent my own house and a 4wd vehicle. A computer which facilitates 4 or 5 dives in a day is utterly useless to me, and so are groups of happy divers drinking and socializing.

 

[tridacna]

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

Nope. I have a backup computer. Sorry Sam, but that's an old specious argument. Solution: Check your batteries before you go diving.

Besides, in hundreds of dives over the past years, I've seen more regulators fail than computers (zero in fact). And they're much more reliable than many people's brains that I've seen.

 

[CT-Rich]

A vacation for me is only partly for diving. I enjoy the unspoiled tropics as much out of the water as in it, so I don't go to places where there is not much to do beside diving anymore. Dominica and similar places where the above water natural world is as seductive and beautiful as the reefs have become my vacation spots. A one or two tank dive in the morning is perfectly adequate for me, with the rest of the day spent exploring the rain forest. Some days I'll skip diving altogether for a hike into the interior to see boiling lakes or long abandoned manor houses, or for an hours long snorkel trip along some intriguing shoreline. I always rent my own house and a 4wd vehicle. A computer which facilitates 4 or 5 dives in a day is utterly useless to me, and so are groups of happy divers drinking and socializing.

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....