Entry Level Dive Comp

[ls1dreams]

Just to comment I do think that divers who use computers still should know tables. In the event of a DC failure, you could fall back on knowing your max depths/times over your first couple of dives and use tables with a conservative square profile to estimate how much surface time you need for future dives that day, rather than being totally stuck.

 

[GreggS]

Just to comment I do think that divers who use computers still should know tables. In the event of a DC failure, you could fall back on knowing your max depths/times over your first couple of dives and use tables with a conservative square profile to estimate how much surface time you need for future dives that day, rather than being totally stuck.

Not a bad suggestion, but some agencies don't even teach tables anymore. SDI, which is my certification agency, is one of them. A dive table was included in our OW package, and the instructor did mention them, but we did not go over them since SDI stresses computer diving. And while some here say redundancy is unnecessary, I always have 2 computers running the same algorithm when I dive so I have a back-up in the event that my main computer should malfunction.

I have looked at my dive tables a few times and am starting to understand them , but haven't really taken the time to learn everything about them. Maybe I will some day before my computer kills me.

 

[dmaziuk]

Just to comment I do think that divers who use computers still should know tables. In the event of a DC failure, you could fall back on knowing your max depths/times over your first couple of dives and use tables with a conservative square profile to estimate how much surface time you need for future dives that day, rather than being totally stuck.

Knowing that my dive on El Aquila was about one hour long with max depth of around 100 feet, I have to conclude I died from DCS two years ago.

 

[EireDiver606]

First of all just to let you know sometimes I come across as more aggressive than I am. I apologise.

@BurhanMuntasser I meant to say decompression theory instead of tables, thank you for pointing that out.

@JohnnyC if you’re diving to let’s say 30m for 25 mins @ nitrox 32, and after you hit 25 mins on the bottom timer, you know “ah” I have to ascend as I only have 5mins NDL left or that your gas is turned pressure. So you ascend to 15m no faster than 9m/min and then ascend for 30secs on/off at 3m per min ascending slowly until you finally do a minimum deco stop at 3m for 1 min if you want?. For that do you really need a computer? This is not a loaded question I promise, but from my GUE course I got the impresssion that you don’t need a computer for rec diving (my instructor didn’t say this) as you just need a comp and timer. Please enlighten me if I am completely wrong and please explain why. Thank you.

Just to clarify, I still dive with a computer but I’m saying it’s better to know your deco in your head, what time you can stay at what depth and record it with a bottom timer to create the thinking diver as opposed to relying on a computer if you have no deco theory at all.

A lot of new divers have no understanding of deco theory (myself included until fundies) and rely solely on a computer.

 

[ls1dreams]

Knowing that my dive on El Aquila was about one hour long with max depth of around 100 feet, I have to conclude I died from DCS two years ago.

Ha, ya, in multilevel dives (like most are), the best you could probably do is roughly estimate an average depth and use that to calculate it, and then just try to be realllly conservative on future dives.

 

[Centrals]

Just to comment I do think that divers who use computers still should know tables. In the event of a DC failure, you could fall back on knowing your max depths/times over your first couple of dives and use tables with a conservative square profile to estimate how much surface time you need for future dives that day, rather than being totally stuck.

I use two cheapies for rec dive and two bottom timers for tec dive.
I did use table for deco dive initially when tec computer was NOT a viable option. And gradually progressed to rely on deco software.

 

[Dan_P]

To put it in perspective, the only agency that actually uses the term DIR anymore is UTD. And they certainly don't do a whole lot of stuff "right." The latest decompression studies quite sufficiently prove that the idea of a human running decompression calculations as taught the "DIR way," is in fact, more dangerous than a computer running a modern algorithm.

Let me try to phrase a question with which I'm hoping solely to illustrate a difference of context (deep stop emphasis versus PDC-free):
If you're running RD and I'm on a GF (whichever GF) and the ascents are similar, how is it more dangerous to run RD?

 

[KenGordon]

First of all just to let you know sometimes I come across as more aggressive than I am. I apologise.

@BurhanMuntasser I meant to say decompression theory instead of tables, thank you for pointing that out.

@JohnnyC if you’re diving to let’s say 30m for 25 mins @ nitrox 32, and after you hit 25 mins on the bottom timer, you know “ah” I have to ascend as I only have 5mins NDL left or that your gas is turned pressure. So you ascend to 15m no faster than 9m/min and then ascend for 30secs on/off at 3m per min ascending slowly until you finally do a minimum deco stop at 3m for 1 min if you want?. For that do you really need a computer? This is not a loaded question I promise, but from my GUE course I got the impresssion that you don’t need a computer for rec diving (my instructor didn’t say this) as you just need a comp and timer. Please enlighten me if I am completely wrong and please explain why. Thank you.

Just to clarify, I still dive with a computer but I’m saying it’s better to know your deco in your head, what time you can stay at what depth and record it with a bottom timer to create the thinking diver as opposed to relying on a computer if you have no deco theory at all.

A lot of new divers have no understanding of deco theory (myself included until fundies) and rely solely on a computer.

Tables work for square dives.

Computers work for dives with either unpredictable profiles or just plain multi level profiles. If you go on holiday and do four dives a day of tropical reefs where all you know before you get in is the depth of the bottom then tables are basically useless.

If you holiday is a bunch of wrecks in 60m then tables (ok, dive planning SW) are probably as good as tables. Or take two computers and dive to a planned max TTS.

Cheap (compared to the cost of a holiday in Truk or the Galapagos) dive computers have changed how people really dive rather faster than agencies courses. The agencies are catching up with the real world thankfully.

Teaching tables is not teaching deco theory. It is teaching how to operate a complicated manual system. Computers can take away that manual part. If your accountant insisted you turn up in person with paper invoices and a Casio to do your taxes you’d laugh and find another one.

You think you have learned the rule of 60, or seen enough profiles you know in your bones how long a dive should be? How about on day 4 of a four dive a day liveaboard?

 

[BoltSnap]

First of all just to let you know sometimes I come across as more aggressive than I am. I apologise.

I had a deep fuzzy feeling that deep down, you are basically a nice guy

 

[EireDiver606]

I had a deep fuzzy feeling that deep down, you are basically a nice guy

Hahaha the same thing with you. I phrase things in a way that aggravates people I know but I can’t help it!.....