Place of dive tables in modern diving

[tursiops]

No, I said if you're buying an entry-level computer, then nobody can tell you how it'll behave. It is not entirely true, of course, as you can find a DSAT computer still somewhat within "entry-level" price bracket, and DSAT is a reasonably well understood. But you can't say that about "RGBM" ones, and let's face it: what the bleep is PZ+ anyway?

3 out of 4 DCs under $200 @ LP are not running DSAT (discount the genesis module-onlies), and it's worse for under $300. (I the tech. specs on i100 @Lp, BTW: "Algorithm: not specified by the manufacturer")

PS. Which ZHL+GF computers are less expensive than Shearwaters?

The i100 runs PZ+, the only algorithm Aqualung is selling now. PZ+ is a Buhlmann ZHL-16C implementation, with unspecified GFs. In terms of NDLs (first dive only) it looks a lot like 45/95, i.e. Shearwater's Rec Low setting. I don't know if Aqualung's PZ+ has a conservatism setting like Oceanic's PZ+, but it probably does since the same guy wrote both implementations. With conservatism, it is in between Shearwater's Medium and High settings.

 

[The Chairman]

Why? Because you'll get a shorter bottom time than you would with an unused computer?

The wrong time is the wrong time. If I see it giving me such a short time while I'm planning, I'm going to distrust it the whole damn dive. What if they set things to 36 and you're diving air? This is why I travel with 2 or 3 PDCs.

Another reason I like PDCs over tables is that the PDC never gets narced, doesn't have fat fingers and if it makes a mistake it's effin obvious. Far, far more reliable than a diver using tables.

 

[Eric Sedletzky]

Until they invent some sort of sensor that they can implant in your body which can detect exact bubbles and notogen load in real time and relay it to a computer on your wrist, all of this is pretty much a crap shoot (within a lot of already done science).
It’s like hitting the side of a barn with a warped shotgun. At least in this day and age we’re hitting the side of the barn, but it’s still a generalization and far from an exact science when you factor in all the different physiologies of all the different people, age, health, etc.
People still get bent on conservative computers on the first or second day of a vacation and they were diving way within NDL’s. Explain that? You can’t.
Alert diver is full of such cases.

 

[dead dog]

Note: I am speaking strictly in the context of recreational sport diving.
I have seen several people (recreational sport divers), in real life, talking about planning a dive using tables where my observation was that they were or would be doing it wrong. One example: "Well, on my last dive I dipped to 90' for a few seconds, but my average depth was probably about 70'" and then proceeding on to use tables based on a first dive of 70', instead of 90'.

Then they were taught wrong. There is nothing wrong with using the dive tables. They go back over 60 years and further. Just use common sense.
History of decompression research and development - Wikipedia

 

[dead dog]

Just get one of these. Nice blend of tables and computer. Be sure to take it on the boat and soak in salt water first.

View attachment 447072

They work better that way. lol

 

[Kevrumbo]

. . .People still get bent on conservative computers on the first or second day of a vacation and they were diving way within NDL’s. Explain that? You can’t. . .
Alert diver is full of such cases

Unless you had prior knowledge of a PFO pathology -->dive tables, a laptop computer or dive computer won't help you in that "unexplained/unexpected" DCS condition.

Rule Out intermediate and slow tissue residual loading with subsequent consecutive dive days of multiple dives per day resulting in supersaturating those tissues into bubbling with a type I DCS symptomology, with worst case type II or AGE compounded by a PFO or right-to-left shunt condition. See Decompression Accident in North Sulawesi

 

[stuartv]

Then they were taught wrong.

So, you're saying that any person who is taught the use of tables correctly will never make a mistake in using them in the future, even if they haven't looked at or thought about a dive table in 20 years?

 

[lowviz]

@stuartv: You may wish to go back and re-read post #192. This is what I am looking for in an instructor. An open, intelligent mind.

"Charge ahead with every conviction that you hold the truth, power, and light. But forever be prepared to turn on a dime."

 

[stuartv]

@stuartv: You may wish to go back and re-read post #192. This is what I am looking for in an instructor. An open, intelligent mind.

"Charge ahead with every conviction that you hold the truth, power, and light. But forever be prepared to turn on a dime."

tursiops made a good post there.

Isn't the point that you don't have to START with a PDC to teach about deco, why it is important, and how to calculate it; the PDC is the end point of the training, not the beginning. You start by talking about on-gassing/off-gassing, and how depth and time affect that. You can make a very simple but telling point with the Rule of 120, and then point out how that is not very accurate except for one depth and for a first dive. How do you get more accurate? Bring in the rule of 192000/Depth^2=NDL for the PADI RDP.....and ask them if they really want to be underwater, watching their air, looking for their buddy, minding their depth, and doing squares and division in their head? And then add that when the dive is over, they still have some nitrogen in them, thus reducing their limits for repetitive dives. How to keep track of all this? Once they realize it is a necessary thing to do, and reasonably complicated, bingo out comes the computer. it is the tool to calculate, not the means to understand.

It seems to be a longer, more detailed version of what I said more briefly in post #155.

...
OW class should make sure they understand the basics of what is happening to the gas in their bodies as they go down/stay down/ascend/off-gas on the surface. They should learn enough to sanity check an NDL. The Rule of 120 (or pick your happy number) may be sufficient. Learn the rules of computer use (e.g. Do not change to another computer after you have already done a dive. If you only have 1 computer and it dies during your dive, sit out the rest of the day.) No need to learn tables.

 

[lowviz]

...//... You table proponents haven't mentioned Nitrox. How does it work out for you to memorize all that table data when you go somewhere to dive Nitrox? Or is Nitrox too new-fangled for you, too? ...

#155 Never got past that. Wallet stays in pocket, won't be you.