Bottom Timer Vs. Dive Computer

[BigJetDriver]

Cave Diver once bubbled...


It all depends on what you are wanting to do. I've planned several dives that *most* computers won't let me do. I've "bent" my computer on a couple of occassions. However since it was just along for the ride to provide profile download capability, it was of no real consequence.

NOTE: IT IS A RULE OF THUMB AMONG THE HYPERBARIC MEDICINE FOLKS (AND SINCE I DO HOLD A DMT TICKET, I CAN SAY THIS WITH CERTAINTY) THAT COMPUTERS NEVER GET BENT, DIVERS DO!

And the use of depth gauge and bottom timers is hardly archaic, as a lot of those people still use computers. They use them to generate profiles before the dive, they dont just take them u/w with them.

NOTE: AS I HAVE SAID BEFORE, AND WILL SAY AGAIN, BACK-UP CAPABILITY (I.E. DEPTH GAUGE, SOME KIND OF BOTTOM TIMER, AND TABLES IN YOUR POCKET) IS A MUST! REDUNDANCY IS LIFE!

There are a few dive computers with capabilities for handling more advanced dives, but most of them are $$$ and I can't justify the price vs. any percieved advantage. I've spent a lot of time running profiles using dive software on my PC and I've gotten a fair understanding of how they generate and I can anticipate a lot of outcomes when I make changes.

NOTE: NO HUMAN BEING CAN EQUAL THE COMPUTATIONAL SPEED AND ACCURACY OF A GOOD DECO METER, ESPECIALLY ONE READING REAL-TIME PO2 AND RECOMPUTING EVERY FEW SECONDS. IF THERE IS SUCH A PERSON, PROFESSOR XAVIER WANTS TO MEET HIM (OR HER)!

I think that is an important factor, because if something goes sideways when I'm in the water, I have a clue on how to deal with it instead of blindly relying on a computer to save my bacon.

NOTE: NO ONE CAN BREATHE FOR YOU, SWIM FOR YOU, OR THINK FOR YOU! ALWAYS STOP, BREATHE, THINK, THEN ACT! (TOM MOUNT, IANTD)

In regard to G.I. I've personally never met the man and most of the comments I've seen him make are very abrasive. But it's very hard to argue with his methods when you see the end results.

NOTE: THANK GOD FOR GEORGE AND HIS FELLOW CRASH TEST DUMMIES! THEY ARE DOING SOME GREAT EXPERIMENTS ON THEIR OWN BODIES. GEORGE IS QUITE PLEASANT IN PERSON. NOW, IF SOMEONE COULD JUST STOP HIM FROM EXPOSING THE SOCIOPATHIC SIDE OF HIS PERSONALITY ON THE INTERNET, HE WOULD HAVE A MUCH BETTER REPUTATION THAN HE DOES AT PRESENT!

/B]

Although this may sound like strange advice, coming from someone who does what I do for a living: "DON'T WING IT! PLAN THE DIVE, AND DIVE THE PLAN!"

Just remember, have a good computer, and use it to its maximum advantage! Just don't use it to replace your brain!

As Mr. Natural used to say: "Get the right tool for the job, kids!"=-)

 

[Cave Diver]

BigJetDriver69 once bubbled...


Although this may sound like strange advice, coming from someone who does what I do for a living: "DON'T WING IT! PLAN THE DIVE, AND DIVE THE PLAN!"

Sounds like we funamentally agree on our diving styles, we just use slightly different methods of accomplishing it.

 

[BigJetDriver]

Cave Diver once bubbled...


Sounds like we fundamentally agree on our diving styles, we just use slightly different methods of accomplishing it.

I believe you're right, but hey, as my diving guru, Frans Vandermolen (IANTD International Advisory Board) says: "Analyze it, test it rigorously, and if it works reliably and well for you, use it!" Or again, as one of our other "Cavers" says when quoting the great explorer Sheck Exley: "What works, works!" (...as quoted by Caveseeker7).

Actually, I remember both Frans and John Orlowski laughing like hyenas at me while I ripped stuff off my rig one time after a run through the caves. After all, they HAD kept saying: "Simplify! Simplify!"...and I had said: "Hey, this has worked well so far (as a deep trimix rig)!" But, as they say, that's another story!

As Tom Mount often says: "If we ever stop learning, we die!" To which I can only say: "Amen!"

 

[Cave Diver]

BigJetDriver69 once bubbled...
As Tom Mount often says: "If we ever stop learning, we die!" To which I can only say: "Amen!"

Yet another thing we agree on.

I see you're in the Houston area. Do you ever dive with any of the swampers out at Twin Lakes?

 

[BigJetDriver]

Cave Diver,

My current rig (when not teaching basic scuba) is an Extended Range Inspiration with seven liter tanks, a Widolf commercial FFM, and OTS military through-water comm gear. Running mixed gas as I generally do, it is not very suitable for the depth regime found at Twin Lakes.

I usually go over to Florida, or down to Belize (Protech on Ambergris Caye) for my personal diving. If you want some great deep open water stuff, give Peter Jones or Roni Lieberman a try at <www.protechbelize.com>! Cheers, mate!

 

[BigJetDriver]

peter_steinhoff once bubbled...

...Write down the maximum allowed bottom time for all depths in your wetnotes and try to remember them if possible. (Try to remember them if possible??????...Ed.)

Make your first dive and during the dive check your time and depth now and then and try to memorize them. If you (sic) diving a square profile it's easy. If not you're probably starting deep and moving up shallower in which case you can use your average depth. It doesn't have to be super accurate - deco theory is a blunt tool.

(SO, IF DECO THEORY IS SUCH A BLUNT TOOL, THEN TEN OR FIFTEEN MINUTES DIFFERENCE AT SAY TWENTY METERS, OR SIXTY METERS FOR THAT MATTER, SHOULDN'T MATTER! AFTER ALL, AS STATED ABOVE..."it doesn't have to be super accurate..."!!)

Anyway, for the second dive you take the depth from the first dive, the bottomtime and the surface interval and put it in your table. Calculate a new set of maximum times and write them down. If you don't remember the times you can take up your wetnotes and look at them during the dive. Or write them on a wristslate if you like that kind of stuff.

And then you carry on like that. What you will see in your table is that you are pretty much clear from nitrogen after a couple of hours. So you'll start over from the beginning again.

Also after you've been diving like this for a while you will notice that you often end up with the same numbers. Mostly because you're diving the same size tanks, profiles etc. Also remember that a minute here or there doesn't matter. Just check the variation on different brands of computers and how much time they say you have left

What does matter however is how you dive, how you feel and your activites during and after the dive. I think Dr Deco wrote some good stuff about that.

And that's the big advantage of using tables. Besides making you more aware of your profiles you can also adjust them according to workload, cold, fitness level and whatever you can think of. As you learn more you can incorporate that into your profile. Maybe throw in a couple of deep stops on the way up, ascend ultra slow the last 20 feets and things like that.

(SINCE YOU ARE ALREADY IN THE EXPERIMENTAL MODE, WHY NOT THROW IN SOME REALLY BIZARRE STUFF LIKE REVERSE SAW-TOOTH PROFILES AND FAST ASCENTS?? AS A DMT, I AM ALWAYS INTERESTED IN UNUSUAL CASES WHEN WE PLAN TREATMENT IN THE CHAMBER.)

Gasplanning is also a breeze because you already know what you are allowed to do (depth/time) before you actually do it.

The downside is that this is not for everybody, just like cave diving or tec diving.

(AS ONE OF OUR OTHER WRITERS HAS POINTED OUT, THIS IS DEFINITELY NOT FOR EVERYBODY. THIS IS TRULY WAVE-OF-THE-HAND JEDI MIND-TRICK STUFF AS PRACTICED BY THE DEVOUT OF THE "AMISH DIVING SOCIETY"! DON'T TRY THIS OUTSIDE THE CHURCH, KIDS!)

The upside is that all you ever need is a $99 bottomtimer and if you start with technical diving, you already have a lot of good skills and habits that you are going to need.

Best,
Peter Steinhoff [/B]

LVX,

If my interjected comments seem a bit sarcastic, I apologize! I am simply trying to debunk some mysticism here!

Let me see if I can make these points more formally:

(1) A diving computer is NOT truly a computer, as we think of it in terms of desktops or laptops. It is a single-purpose miro-processor with a specific program or algorithm built into it. Its job is to do the computations that you have been taught to do when using the tables. The benefit is that it can, and does, sample real-world parameters (depth and time, at a minimum) and constantly re-calculate your totals, usually at an interval of one to three seconds. (If you can calculate faster than it can, Professor Xavier has a place for you in his school!) REMEMBER, HOWEVER, THAT A GOOD DECO METER IS JUST A TOOL. IT IS A GOOD TOOL, BUT STILL JUST A TOOL!

(2) The computer is a piece of mechanical equipment, like your regulators, or lights, etc. It can fail, and if it does, the question is: "What are ya gonna do now, soldier?" It then follows that you should have an understanding of your tables, how they work, and what they do for you. This is where you take out your back-up tables, and refer to your back-up bottom timer and depth gauge! As Tom Mount of IANTD says: "Stop, breathe, think, then act!"

To sum up: "Is a good dive computer an excellent diving tool? Mais certainement! Absolutely! But should you blindly utilize one without understanding the basics? Not only no, but Hell no! That makes about as much sense as blindly following the rantings of the Great God Trey in the "Amish Diving Society"!

As Mr. Natural used to say: "Get the right tool for the job, kids!"=-)

 

[Cave Diver]

BigJetDriver69 once bubbled...
Cave Diver,

My current rig (when not teaching basic scuba) is an Extended Range Inspiration with seven liter tanks, a Widolf commercial FFM, and OTS military through-water comm gear.

Wow! Say that three times fast! lol Well I guess I wont see you at that mud puddle. Maybe I'll catch you in Florida some time.