Teaching Dive Tables (including Nitrox)

[Valeriy_Kulaha]

Tables do exist separately from physiology.

When you teach scuba, you teach physiology, and you teach decompression theory.

Then you teach how to manage decompression. It could be with tables. It could be with computers. It could be with both.

In many cases, instructors taught decompression theory along with how to use tables, so many people mistakenly believe that that are the same thing, but they are not. Mark Powell wrote an entire book (Deco for Divers) on decompression theory without once teaching how to use tables for NDL dives.

The tables are a quantitative measurement of decompression in meters and pressure.

 

[Valeriy_Kulaha]

Although this is a bunch of nonsense, your tables know none of this, either. And if you've been guzzling beer, but insist on going diving, you are more than likely to miscalculate using your tables anyway. So a computer would still be the best way to go.

In the army, my tables were calculated by the dive director. He also monitored my dive from boat. I could only refuse the dive due to poor health.
Later I planned my dive myself:
- what depth and duration
- calculation of the amount of air for each stage of the dive
- when to start the ascent and the duration of stops
My craziest activity was collecting rapana shells in Varna, Bulgaria in 1991. Going out in the morning on a boat I had up to ten cylinders for several hours. At three o'clock a shell buyer arrived at the port. I understood that I was slowly killing myself, but I needed money to live during the devastation after the USSR.

 

[Valeriy_Kulaha]

Can I please get your tables that take into account alcohol consumption and hangovers? Asking for a friend.
:ура:

The world is changeable and no computer can calculate what awaits me around the bend in the road!
My advice: after looking at the computer, listen to your own ass - maybe it's just time to go to the toilet. :пьяные:

 

[Valeriy_Kulaha]

Although this is a bunch of nonsense, your tables know none of this, either. And if you've been guzzling beer, but insist on going diving, you are more than likely to miscalculate using your tables anyway. So a computer would still be the best way to go.

The computer also doesn't know about the beer you've drunk! Because its memory only contains the same tables!

 

[The Chairman]

The world is changeable and no computer can calculate what awaits me around the bend in the road!

This makes absolutely no sense. PDCs do a great job of dealing with multi-level dives, and excel if/when your target depth is wrong. I remember where I've neem dropped off in 60FSW only to end up going to 100FSW. Tables aren't flexible enough to keep up with that safely. They're even more important where you don't know the depth you're going to, like in a cave. Up, down, up down, I'm following the cave's profile and can't keep to a specific depth.

Yah, I don't buy into your luddite approach, and I doubt that many do. I love my Shearwaters.

 

[gschaut]

How to stay alive during a dive and not get decompression sickness - is this unnecessary and unnecessary for a student? The computer knows everything? And if the computer goes out at depth, then we are all mortal.
Thus, pedagogy turns from science into charlatanism.

For what it's worth, this is page 1 of my primary computer's owner manual.

 

[GreggS]

No computer can plan an upcoming dive. Therefore, it cannot calculate the required air supply for the dive. And if you have an increased air consumption, your computer will not help you!

I missed this little gem from earlier in the thread. This could not be more false. My Shearwater Peregrine TX keeps track of my air pressure, air consumption, and depth amongst other vital information. Using all this information, it tells me exactly how much time I have until I reach 500 psi. I can see all this information in a quick glance at the computer. Could something happen to the computer? Sure, anything is possible. But I carry another computer as a backup that gives me the same information as the primary. Could something happen to the transmitter that both computers read to give me this information? Again, yes. But if that happens, as @boulderjohn said, if neither computer is giving me the information I need, I simply go to the surface. I will not be so low on air that I can't slowly and safely make it to the surface when that happens.

But you be you and trust those tables. My computer gives me the information I need and I trust it.

BTW, I was never taught tables in either OW or AOW nor when i certified for Nitrox. I've been to over 100 ft (33 m) deep on many occasions and have never had a problem nor taken a DCS hit.

 

[boulderjohn]

The tables are a quantitative measurement of decompression in meters and pressure.

I have no idea how this responds with my statement to which you were responding. Not the slightest.

I also don't understand what it means, and I can't begin to estimate how often I have taught tables.

 

[tursiops]

I have no idea how this responds with my statement to which you were responding. Not the slightest.

I also don't understand what it means, and I can't begin to estimate how often I have taught tables.

If V_K is not a very poor AI bot, then he is a very good imitation of one.

 

[Belzelbub]

The tables are a quantitative measurement of decompression in meters and pressure.

No. The tables are a simplification of models done with depth/pressure and time. They were developed as a (relatively) easy way for divers to stay on the safer side of things. Originally from studies done, then the different agencies tweaked them a bit for additional conservatism.

And what do you think the computers are doing? They are measuring pressure and time and making calculations throughout the dive about what might be happening with the diver's tissues. They can't know for sure what is going on with the diver's body, but neither can the tables.

The world is changeable and no computer can calculate what awaits me around the bend in the road!

You are right, the world is changeable (changing?). Yet you seem to argue the other way. The diving world has largely moved on from tables and has embraced computers. If diving with a computer instead of tables was as dangerous as you seem to think, then I would expect that the accident statistics would show a significant increase in DCI. Yet, everything I've seen doesn't support your hypothesis.

My advice: after looking at the computer, listen to your own ass

This might be the only correct statement I've read from you in this thread. You are absolutely right. No dive computer, dive table, or rule of thumbs can predict what is actually going on in the diver's body. The diver needs to use their head (assuming not permanently inserted in their ass) to decide what is safe for them. The computer, table, etc. are only tools that can provide the diver with information that could help in a decision making process.


I first learned to dive using a dive computer. My first 100 or so dives were done without a computer. I just consulted the tables. I still have my original OW table and my Nitrox table, but haven't used them to plan or execute a dive in a real long time. I've used computers since then. They are just a lot more convenient, and can actually take into account some level of changing conditions on a dive. In real-time.

For example, suppose a diver goes a bit deeper than their planned depth. It shouldn't happen, but I've read enough stories to know it happens all the time. They got a bit distracted following the reef line, and didn't pay close enough to their depth. The diver that planned with the table (that's up top on the boat) may have a bit of a dilemma. Are they still within NDL, or do they have a stop they should be taking. Unless they've memorized the tables, I guess they'll find out on the boat. For the diver with a computer, they will know whether they have exceeded NDL, or if they are still OK to continue. They have an updated plan of how to get safely to the surface.

Divers should be taught the basis of what happens during a dive. They need this to be safe. This can be accomplished with the accompaniment of tables or through the use of a computer. More often than not it's the computer today. When my daughters were first learning, I was a bit surprised that there wasn't as much of a focus on tables as when I first learned. Then I thought about it and realized I'm OK with it. The world has changed. So many aspects of life today are different than they were years ago. Why should scuba diving be different?