Redundant Backups

Hi,
Does anyone have any thoughts on carrying a backup computer? I'm thinking of getting an AI unit (mares MC1 or Uwatec smart com) and having a backup wrist based computer. Now I'm not sure about the necessity of doing this, but I'm going to assume its a good idea to "cover my a$$" on this. What I'm wondering as well, is should the backup be from the same company (and use the same algorithms) or whether products from 2 different companies are a better idea... if using 2 different companies computers, then only one would be used during the dive, unless it had a catastrophic failure. I'm planning a little ahead here, as I'm not yet certified (should be in 2 weeks tho), but I want to start planning future gear purchases.

Jase

If you can afford it then go for it but I would make it a later purchase. Get your other stuff first, BC, Reg, etc..... I dive with two computers of different manufactures and dive the most conservative one when underwater so as not to violate any deco obligations.

Just carry one computer and a backup depth gauge/bottom timer. If the computer takes a dump you're going to abort the dive anyway so another computer isn't really necessary and the bottom timer will still give you the max depth and time of the dive. The timers are much cheaper then another computer and gives you some kind of back up. Both OMS and Uwatek make nice units that you can find for less then $200. I bought a nice OMS unit on Ebay awhile ago for $80.

Ditto to Padipro

I've got two computers. One I leave topside and the other I put on my right wrist. I have the AI feature (that I don't use) on one and not on the other. Both happen to be made by the same company. Here is my take on the whole computer thing:


Use an SPG for your tank pressure. It's way more reliable than AI. If your computer fails then you have no way of knowing what your psi is. Dive over and you are on your way to the surface.

Know what your max bottom time/depth is for whatever gas you are using before you dive.

Learn how to shape the curve.

You will know what your profile should be. If your computer fails then you should be able to go off your buddies depth and time to finish the dive. Just be extra conservative on your profile and stops. Should you abort your dive? Up to you. If you have AI then absolutely. If it were me (and I was in NDL), I would know what my psi was and would know what my profile should be and could finish the dive albeit conservatively.

Yes I know we are taught not to use another persons computer. What happens if you lose a mask and have to depend on your buddy to help you make your ascent and stops since you can no longer see. You will be using his computer/ depth timer then. The same general rules apply if your computer bites it...

I dive 2 computers, one is AI and one is not. I also have a standard SPG which I use religiously. I really didn't care about the AI, but it came with the computer so I use it. Both of my computers are wrist mounts.

The AI is a nice handy thing since it is right there on my wrist, but, I wouldn't bet my life on it.

As previously said, get the important stuff first, don't worry about the computer. It's going to be a while before you'll be doing any diving that it will be really handy for and who knows, by then you're whole attitude about diving and the gear you need will have changed.

Quarrior:

I dive 2 computers, one is AI and one is not. I also have a standard SPG which I use religiously. I really didn't care about the AI, but it came with the computer so I use it. Both of my computers are wrist mounts.

The AI is a nice handy thing since it is right there on my wrist, but, I wouldn't bet my life on it.

As previously said, get the important stuff first, don't worry about the computer. It's going to be a while before you'll be doing any diving that it will be really handy for and who knows, by then you're whole attitude about diving and the gear you need will have changed.

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Can I pop in a question here... I am a new diver and not going to be buying a computer anytime soon (just got my BC and reg set for Xmas!!!). But... I think I would really like an AI... for ease of use... but have to admit.. .I would like the redundancy of a regular pressure gague (if push came to shove, would always rely on the SPG first and foremost). So, can you have both on one set of regs? Sorry for the dumb question.... :06: Thanks!

Amy - I have dove with Quarrior and seen his set up. Yes you can do both. Most reg 1st stages have two HP ports. You can run your spg off the left side and the AI off the right.

AmyJ, depends on your reg set. I have a ScubaPro 25/500 and it has to High pressure ports so I could have the transmitter on one port and my spg on the other (tried it but the transmitter is dead and never made it to the water, the manufacturer said Im screwed 'cause its too old. Again transmitter died before ever being used!) I also have an older Sherwood reg set that only has one port. In a perfect world where nothing ever goes wrong Id like to have an AI wrist computer (that works!) and a SS1 inflator/octo. That'd be so cool to have my primary hose and inflator hose... owell.

AmyJ:

Can I pop in a question here... I am a new diver and not going to be buying a computer anytime soon (just got my BC and reg set for Xmas!!!). But... I think I would really like an AI... for ease of use... but have to admit.. .I would like the redundancy of a regular pressure gague (if push came to shove, would always rely on the SPG first and foremost). So, can you have both on one set of regs? Sorry for the dumb question.... :06: Thanks!

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Yes, you can have both an AI and SPG on the same reg set, that is what I do. My AI works with my wrist mounted Vytec computer. My SPG is just that, an SPG and connected to a D-ring on my left waist via a clip.