Dead computer - No backup

[patnee]

my uwatec dive computer failed on the second dive of the day
when i saw it i just went up to 15 feet for 30 bar and then surfaced
i was annoyed as it had 80% battery so i knew it was broken
i have a pressure depth/gauge on my regs which combined with a computer is all the back up i need
why people feel they need 2 computers is beyond me
just one more thing to lose,maintain and get stolen
i lost half of one dive and did not dive 4 the rest of the day thats all

 

[water_monkey]

An easy and relatively cheap solution is to have an analog spg and depth gauge. There are quite a few relatively small ones and yes, while you will have extra baggage, it is easy to keep in place. You won't have a computer, but you will know how deep you are and know how much air you have. Even with a computer, I still bring my watch, so you even have timing.

 

[Freerolling]

I just bought a back up computer because of this thread.

I started diving a couple of years ago and quickly adopted a wireless Vytec as my only source of air/depth/etc information. I really liked the reduction in hoses and the ability to have everything on my wrist. I since sold my Vytec in favor of a D9...why, you ask? Because it looks cool and chicks will dig me underwater.

Anyway, after reading all these posts, I decided that the time my computer craps out I will at a minimum be inconvenienced on a dive vacation; if I'm in mid dive, I'll have to get my buddy to take me up; and I could get myself into a nasty situation.

I therefore made a resolution to get a back up device. I started by thinking I needed an air pressure gauge. Gotta know how much gas I got if my computer craps out. Then I thought, depth is pretty important too in case the one time my computer craps out I just happened to have triggered decompression requirements for my ascent. So, by the time I realized I wanted air and depth in a console, I just felt I might as well opt for another computer altogether and get the best redundancy possible.

I bought a Suunto Cobra to go with my wireless D9. I'm finding quickly that I'm not the only wireless fan who has done this. Now my dive vacations are better protected from computer failure, since I could dive with either piece of gear by itself if I had to. More importantly, I feel much better knowing that if I have an underwater computer failure, I won't have to abort the dive.

Anyway, thanks to all who posted here. I really felt like it helped me make a good decision that I'm very happy with so far.

 

[tschmitt]

Thanks for posting this thread. As a recently certified diver, this is exactly what I was thinking about. I purchased an air-integrated Suunto Cobra. Love all the computer features and how it keeps track of everything. Got me to thinking, what if it craps out on a repetitive dive at 60'+? I can see how too much computer reliance can easily put you/buddy in danger.

I decided to purchase a small backup SPG to go along with my Cobra. I have a SP MK25 1st Stage and it has another HP Port. The only thing I don't like is the SPG runs along the right side, possibly to be confused with a second stage hose (in reg recover event, etc.). I like the idea of an analog backup of some sort for gas and depth, although two computers should provide adequate redundancy for rec. diving.

Does anyone have this kind of setup? (Air-Integrated Computer + backup SPG)

Should I just go for dual cpus ? If so, can anyone recommend a reasonable backup dive computer?

 

[peterbj7]

The reality is that at any point in your dive you should have a reasonable idea of how much air you have and how much remaining no-decompression time. Then there's no panic if all your instruments fail, you just make a gentle ascent. Of course this comes with experience, but it's a skill set well worth acquiring.

 

[Tigerman]

The reality is that at any point in your dive you should have a reasonable idea of how much air you have and how much remaining no-decompression time. Then there's no panic if all your instruments fail, you just make a gentle ascent. Of course this comes with experience, but it's a skill set well worth acquiring.

Yup.
But having tested this on purpose I could see quite well how easilly you can screw up royally if you DONT pay attention to your timers and gauges..

 

[ba_hiker]

The simple solution (assuming your dive computer has a user serviceable battery) is to always carry an extra battery with you.

Two years ago in Curacao my daughter's Aeris ATMOS AI indicated low battery during the pre-dive check. We simply dug out a quarter and opened the battery port, replaced the button battery, replaced the battery port and we were all set to go.

Computer failures are extremely rare (excluding low battery which is preventable by having a spare).

Diving conditions where I live are similar to yours but somewhat colder (as cold as low 40^o F).

I was on a live aboard dive boat on a three day dive trip when my AI computer failed. the boat crew wouldn't let me dive for the rest of the day, even though I had and replace the battery.

The problem, as they saw it, was that my residual nitrogen loading was no longer known, and thus I could not safely calculate my NDL or safe bottom time. Luckily, for me, It was the next to last dive of the day, so I only missed one dive.

My next live aboard trip (a 5 day trip with a company known to be strict about requiring computers to dive), I had redundant computers. Both are the same brand using the same brand and use the same battery (keep spare parts list short!). I pair both with a single pressure transmitter. I have a SPG to provide backup pressure info. Still in my infinite paranoia I really would two computers from different companies, to reduce the possiblity of common mode failures...

What I found interesting is that both computers indicate similar depths. At about 100 ft they read within 2 feet. The newer one always indicates the deeper depth. Two feet is close enough for me.

 

[gaudencio]

March 08, I was diving in PG with my almost new ( just had 16 dives ) TEC 2G uwatec compputer also have with my my dive watch.. this was my first dive for the day and when we were at around 80 ft. my comuter registered error. ( with a wrench) on the dial. i informed my dive-guide and showed him my computer. But we continued the dive. I just surfaced with them at the same time and had the regular 3 min deco. What I was thinking is luckily that this dive was not done in the Canyons of PG. Which has a strong down current. What if ending the dive and we all ascended and the group got separated and there was a fast down current where you cannot tell if you are ascending or not. I can only sense that I am decsending bec. my eardrums are tightening and its getting darker and darker. With this scenario it would be very hard to ascend at normal 60 ft/min. Since your smallest bubbles are descending with the current.
So having this thought, I am planning to buy a backup oil filled depth gauge console together with an SPG. This way I can monitor my depth and still be safe after my computer breaks down.

 

[peterbj7]

By far the simplest way to achieve redundancy is to wear two computers, one at least preferably watch style as they're smaller. Plus a normal SPG. But as I've said before, I don't know why anyone should need their air pressure on their arm - most experienced divers only check it a very few times a dive.

The problem, as they saw it, was that my residual nitrogen loading was no longer known, and thus I could not safely calculate my NDL or safe bottom time

So don't tell them!

 

[ba_hiker]

So don't tell them!

Well the real issue is tracking you residual nitrogen loading. This is particularly important in a multi dive multi day trip. If you don't know this in when doing multiple dives, you can easily exceed your no-deco limit.

I often reach 80% or more of my nitrogen load after a three dive day. This means that I could easily exceed my no deco time on an additional short shallow dive.

Do you calculate your repetitive dive group on every dive with a computer? If you don't know this at the start of a dive, then a SPG, depth gauge and clock are not a backup.