If a computer fails at depth, and you have a decompression obligation...

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Posted by CalAbDiver on July 20, 2001 at 13:36:15:

In Reply to: Re: Different take on "No Computers" posted by Reefraider on July 20, 2001 at 13:08:13:

...THEN you are in a world of hurt.

Stop, Breathe, Think, Act. You still have a lot of gas left in your tank.

If your loss of your dive computer means you lost your SPG and your depth gauge also, you are REALLY in a world of hurt, and if you didnt have backup gauges, then you would need the help of a buddy to egress safely, because you cant do it very well alone.

if this was a solo dive, and you didnt have equipment redundancy, then see you at the deco chamber, if you make it that far before your stroke. you might try very slowly to follow the small "champaign bubbles" using 10 deep breaths as an approximation for 1 munute of time, and timing your ascent so that you give back all the deco obligation by a slow ascent. but even then, see you at the deco chamber.

if you have a spare lift bag in your B/C pocket and a reel, you could run up a line, and then pull yourself up slowly, using arm spans as a depth indicator. you could subtract them from your last know depth before the computer failed.

If your dive computer was a wrist model, thats not as bad. You still have information on the amount of pressure in your tank(s) presumably from your analog SPG. you might not have another clock, but 10 deep breathes per minute is a good approximate clock, if you need a clock.

did you memorize your decompression plan before you dived it? If yes, then just go ahead and execute it from memory, using your breathing as a clock.

if not, then begin your egression. Compute how many stops you need to make in 1/2 increments from depth. so if you are at 127 fsw, your first stop will be at 63 fsw, your second at 31 fsw, your third at 15 fsw, etc for deeper depths, which you shouldnt be diving deeper without additional certification.

a 63' and 31' and 15' stop totals 3 stops, so consume 1/3rd of your gas in psi at the first stop, 1/2 of the remaining gas at your second stop, and all but 200 psi of your gas at the third stop.

i hope your analog SPG is accurate enough so that 200 psi gives a valid reading of remaining gas. the advantage of this regimen is that you dont need a watch to compute it, and in all likelihood when you lost the functionality of your dive computer you lost your only clock also. due to decreasing ambient pressure, you will be staying proportionally longer at the shallower stops, which is good.

Stop, Breathe, Think, Act. that will get you out of almost any jam.

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