Dive Computers---Not if, But When!

[azsilver]

Go ahead and do the training. It teaches you a lot about diving that is valuable to even the recreational diver. You'll be more confident and a better diver for it.

Thanks for the information---I do believe additional training is valuable!

Knowing what to do and training for it makes one safer when something out of the ordinary happens-failures of equipment---computers---regulators---etc---training with your buddy to work as a team during an emergency saves lives.

Because in life things can and will go wrong!

Thanks,

An AZ diver

 

[MarcHall]

OK, I'll bite on this. I agree, one must know their dive profile and stick to it. What I don't agree with is memorizing tables, especially for deeper technical dives. Now, while you won't dive deeper than 100' on Nitrox, 99.9% of diver's do. Let's not get into trimix diving in this thread. Having MOD's and NDL tables in your head for deep dives goes out the door when narcosis sets in. That's why we mark our tanks with big MOD numbers and use slates, wetnotes, or computers.

Again, Marc, I know you've limited your N2 by going He below 100, but even with a clear head, relying on memorized tables is a bad idea. The problem is, you run the wrong schedule once by mistake and you're in trouble. Why not just pull out the wetnotes on every dive.

I'm sure you don't teach that technique to your students.

I fly for a living. We use checklists for every flight. Some checklists are short, some are long. After flying the same aircraft for many years up to 6 legs a day, one tends to know the checklist by heart. But, we still read them, because missing one item can kill ya.

Limiting N2 is part of the equation but not the major one. More important is to reduce the density of the gas.

Some divers may choose to dive Nitrox or Air to depths greater then 100 feet. Some divers may choose to smoke a few cigarettes before their dive as well. They won't be diving on my team.

If you keep things simple then its easy to remember them.

As an example

Since I use GUE/DIR standard gases the MODs are:
Nitrox 32 - 100 feet
30/30 - 120 feet
21/35 is used for recreational depth diving below 120 and a bit beyond.

There are no other MOD's I need to keep track of for recreational diving. There are a handful more for tech diving.

I don't memorize tables although the NDL's have been embedded in my brain for many years.

I don't use tables to develop my deco plan.

I don't keep tables written in my wetnotes.

I don't use a computer program to develop my deco plan.

I do use a rules based system and it's description is kept in my wetnotes. If I need to break it out I will.

For deco dives I do develop my deco plan before I enter the water for the planned dive and I will write it down in my wetnotes. But since the shape of my deco curves are consistant its very simple to quickly calculate what the stops should be anyway, even if there is a change in the dive profile.

I do teach a kernel of this to my recreational students. I don't teach tech diving - that's for more experienced divers to teach.

Take care

Marc Hall
www.enjoythedive.com
www.sdue.org

 

[Hobbs]

first I asume that you are diving within the NDL limits.

then if anyone of your two computers fails just end the dive and go up slowly to the surface. the chance of both of them going bad at the same time is very low, if you buy one more then you will have a third computer not to share, but to validate the one that you already have on you. then you will be able to dive with that computer
if one of yours break. just wait a day and you can use that computer instead of the broken one and still have two..
if anyone of the three breaks and you have been good buddys then that should be quite visible wich one by simply checking all three. they should not be overly off from eachother. unless you have different settings.

and of course since this is a matter of money, IF you can afford buy 2 backups and 2 primary computers that is preferable but might be overly cautious..
but you are the ones diving, YOU have to make the risk assessments.

if all computers breaks
if all else fails then do it the old style... follow the smallest bubble you can find and always look for a smaller bubble and keep the smallest bubbles pace to the surface..
thats how I was tought once upon a time..
when dinosaurs where roaming freely.
thats still ok since you have gotten to the surface WITHIN the NDL

so even if all computers break you will still survive unharmed if you are prepared mentally for it.

good luck