Redundant Backups

[StSomewhere]

Or... how about you save a ton of money and buy a simple SPG and simple wrist computer or two

Because some of us like the AI features?

 

[Charlie99]

How about you use the AI computer and non-AI computer, and keep an SPG in your gear bag. That way if either computer fails you can abort the dive but keep on diving after that.

Or... how about you save a ton of money and buy a simple SPG and simple wrist computer or two

That's pretty much my opinion also, except that I don't see a need to dive with 2 computers.

There are 2 reasons for redundant computer and SPG. 1) for safety 2) convenience of not having to abort the current or future dives.

You should always have enough air for both you and your buddy to safely complete the dive, so loss of air pressure readings on an AI computer should NOT be a safety issue. Just gracefully and calmly abort your dive, using your normal ascent and exit procedures. Similarly, you shouldn't be going past no-stop limits without knowing it. Should always know enough about your decompression status to complete the dive without a computer.

Even in the case where you need depth and time info to safely complete the dive, you still have your buddy. For me, a backup computer is a safety requirement only for dives with significant decompression obligations; and those dives where viz is so poor that I can't judge depth, and where buddy separation is not just a remote possibiilty.

As for the convenience side of things; if your AI computer is so unreliable that you are aborting and losing a lot of dives because of it, you need to get more reliable gear.

 

[jonnythan]

Having two comptuers but leaving one on the boat doesn't really do much good for you until the next day if the first one fails, does it?

In any case, I think the fact that the question of backing up an AI computer gets asked so often is reason enough to do without it.

 

[Charlie99]

Having two comptuers but leaving one on the boat doesn't really do much good for you until the next day if the first one fails, does it?

It would do me a lot of good ...... by telling me both depth and time on the next dive.

I would have to plan the profile of the next dive rather conservatively due to the greater ambiguity of my previous profiles.

Before you assume that you would have to end all diving upon a computer failure you should look at the effect of adding a 10 minute hang at 15' to the tail end of whatever you use for your normal ascent procedure from NDL dives. Play around with V-planner or other deco program a bit.

Obviously, this sort of "dead computer fallback plan" is something that is better to do ahead of time, when you can review it carefully and reflect upon the alternatives.

 

[RICoder]

I don't think this has been mentioned.

How about you use the AI computer and non-AI computer, and keep an SPG in your gear bag. That way if either computer fails you can abort the dive but keep on diving after that.

jonnythan is right on the mark here...that's what I do. Figure an SPG shouldn't set you back more than $100, which is worth every penny if it keeps you wet on a vacation.

 

[jonnythan]

I don't even dive with a computer anymore. I'm speaking in reference to the original poster..

 

[Mako Mark]

I use two computers, hate AI because it is just too much info in a digital format to take in at a glance (JMO).

I have only once had computers fail, and they both failed simultaneously.

 

[RICoder]

You also indicated that you are not yet certified, but will be soon. To this I have what will probably be advice you do not want to hear. In short, DO NOT make any major gear purchases for a while. I would encourage you to wait until you have about 50 dives or so before you buy anything major. During your first 50 or so dives rent lots of different brands of equipment and different styles. If you must buy gear then look at e-bay for used gear.

Yeah, I didn't notice that you weren't cerified. It is oh-so-tempting to blow a lot of money on the cool new toys, but in the long run you will end up with stuff you aren't happy with. Buy a nice reg if you must spend some money, maybe a bad-a$$ BC. Don't get a computer until you know what you want. Buy the SPG, because in the end, you are going to want to have one anyway, so it will not be wasted money.

 

[scubatwinned]

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

Hi, as a new diver learn how to dive first... bouyancy, seeing what is going on around you, watching your air, depth, dive time. The people that I have run into that are gear orientated instead of getting the basics down first - which takes at least 50-100 dives in my mind - have been shunned by other divers. They are over geared and take way to long to suit up and get in the water. 2 computers, pony bottles etc, KISS- KEEP IT SIMPLE STUPID(not meaning you) just a good rule of thumb to follow. As a new diver picking your dive buddy is probably as important to your safety as your gear.learn the tables first before diving with a computer, these will keep you right if your computer goes down. By writting your no deco limits on a slate for the planned times,depths and one shallower and one deeper if computer goes tits up your good. When you get into the water and drop a few feet below the surface the computer automaticly turns on. So there is no way only one can be used. Having the same for primary and backup is peace of mind - know one know the other - see what you need to in a glance, don't have to think about it if you are in a situation. Again KISS!!! There is lots of time to get the gear.

 

[ShakaZulu]

I dive with four Mosquito's, one on each wrist and one on each ankle...........your buddy has your backup. Just call the dive when your fail. Live to dive another day, now if you are diving solo........