Info Why are tables not taught in OW classes anymore?

[lowwall]

Something I do always wonder about is why the little bit of extra conservatism using tables vs. computers is not mentioned in courses and materials. I'm not talking about square profiles vs. multi-level computer dives or any of that. I mean that when you do a maximum dive of say 90 feet you may be right on the bottom once in a while (oh yeah, never ever touch the bottom....). But most of the time you are at maybe 86-87 feet. Now when you figure 90 feet with tables you aren't really at 90 much at all, even with a very square profile. So, you have a little edge there. With the computer, you get the theoretical "exact" bottom time remaining on the screen. There IS no leeway if you mistakenly let it go down to 0 or close to 0. It is what it is. This is NEVER mentioned.

Except all the computers build in a conservatism factor to their algorithms. They won't give you the same time that a table shows if you did the maximum possible dive (i.e. squarest possible profile to the maximum depth for one of the table settings).

 

[inquis]

There IS no leeway if you mistakenly let it go down to 0 or close to 0.

Use of tables add a variable bit of cushion by virtue of being shallower than planned. The computer yields a consistent bit of cushion via various other means. Cushion is cushion, IMHO.

 

[Doc]

Cushion is for the pushin’

 

[Eric Sedletzky]

The one problem I see with modern day computer use is that some people will always want to “milk” every last drop of bottom time out of every depth. This is known as “riding” your computer. I think this could lead to hyperbaric stress, especially over several days in a row.
Computers allow for that even being used correctly, tables do not (if used correctly). But that’s not to say that tables were not abused either by people ignoring the rules or trying to outsmart themselves by coming up with some “averaging” solution to try and make tables work like a computer. Tables also don’t beep or lock you out so there is a lot more personal responsibility and self control to make sure you’re using them correctly and paying attention. When I started diving I thought it was kinda cool to be doing something dangerous enough that I had to pay attention, be responsible and keep track of depth and time.
In todays world people can’t be bothered with anything more than they have to do. Tables would be a disaster.

 

[rx7diver]

I work at a university (actually, at the system offices for a university system consisting of four research campuses), and one message that I try to leave with students who are taking (or contemplating taking) the scuba course taught at the flagship campus just down the street from me, is that scuba can be done safely without requiring the purchase of a lot of expensive, optional gear (like PDC's, IMHO)--despite what the students might read to the contrary from what some people post in on-line forums.

Students--anyone--absolutely can partake in this activity, safely, without breaking the bank! (I, myself, learned and made my first gear purchases when I was a graduate student living on GRA and GTA stipends!) Cost will NOT be a barrier to admission to this activity, if purchases of extraneous, unnecessary gear are avoided.

IMHO, students should be more concerned about just how they will prepare the game fish they speared, for the evening feast after a day of local diving at Bull Shoals Lake, AR. For example.

FWIW,

rx7diver

 

[Divedoggie]

We teach tables for all our Open Water Classes. This is a segue into a thorough presentation and discussion on dive computers. Kind of like having a basic understanding of math before using a calculator. The students are also taught that as long as they record all their dives, they can switch to dive tables if their computer fails.

Friends don't let friends dive with operators who will take them out without a computer or a dive plan.

 

[TMHeimer]

Use of tables add a variable bit of cushion by virtue of being shallower than planned. The computer yields a consistent bit of cushion via various other means. Cushion is cushion, IMHO.

Point taken-- I see what you mean. So in effect, if one's DC reads 0 bottom time you aren't really quite at 0?

 

[johndiver999]

The one problem I see with modern day computer use is that some people will always want to “milk” every last drop of bottom time out of every depth. This is known as “riding” your computer. I think this could lead to hyperbaric stress, especially over several days in a row.
Computers allow for that even being used correctly, tables do not (if used correctly). But that’s not to say that tables were not abused either by people ignoring the rules or trying to outsmart themselves by coming up with some “averaging” solution to try and make tables work like a computer. Tables also don’t beep or lock you out so there is a lot more personal responsibility and self control to make sure you’re using them correctly and paying attention. When I started diving I thought it was kinda cool to be doing something dangerous enough that I had to pay attention, be responsible and keep track of depth and time.
In todays world people can’t be bothered with anything more than they have to do. Tables would be a disaster.

It seems like people brag about this activity on this forum. Maybe I am misinterpreting what they mean.

So for example, riding the computer would be maxing out the no deco time at 100 feet (or close to it), then come up to 60 feet, dive there for a good while and then come up to 40 feet and spend a good bit of time there. I get the feeling this sort of thing is not that unusual?

 

[lowwall]

It seems like people brag about this activity on this forum. Maybe I am misinterpreting what they mean.

So for example, riding the computer would be maxing out the no deco time at 100 feet (or close to it), then come up to 60 feet, dive there for a good while and then come up to 40 feet and spend a good bit of time there. I get the feeling this sort of thing is not that unusual?

I've done a lot of tropical dives where you get close to NDL at approx 30m/100', then work your way up to the top of the reefs at around 10m/33' and hang out there for 10-15 minutes before ascending for a safety stop.

That kind of profile is creates less decompression stress on the body than if you had ascended straight to the safety stop from the deepest part of your dive.

 

[Edward3c]

I was overseeing a student in planing their depth progression dives to 30 and 35m last Saturday. Yes we used tables as the planing mode of most computers don’t give the deco times needed for gas planing.

These were recreation dives not technical.