AI Computers and Backup Analog

[nv]

My suggestion for AI computer users is to have an spg as well. it can be a small 1.5" one clipped off to your waist or chest that you only need to use to verify that your computer is reading the correct pressure prior to starting your dive or in the event that your transmitter fails, link is lost, or you have a complete computer failure. Carry a watch with depth gauge (even timex make one now for $200 or less) or bottom timer as back up with tables and you should be fine, no need to sit out 24hrs especially if you are doing NDL diving.

I was considering clipping it to a D-Ring in the event of comp failure and to check accuracy of psi before each dive. It's a combo, and at the cost of a spg I might as well use that correct?

 

[RJP]

I was considering clipping it to a D-Ring in the event of comp failure and to check accuracy of psi before each dive.

If you use one to check the accuracy of the other, and they don't match, how do you know which one is wrong?

 

[herbdb]

I still dive with a full nav console on a retractor. I own it and it doesn't get in the way so why not have a complete backup.

 

[nv]

If you use one to check the accuracy of the other, and they don't match, how do you know which one is wrong?

You don't, but a wise individual will definitely continue, if they choose, by the gauge reading a lower psi.

 

[moody s]

The 24 hour rule is conservative and an easy rule of thumb to go by. If you did only one shallow, short dive you may be able to get back in after 12 hours. Yes, you may be able to use your tables as a back-up in this case.

However if you have done multiple dives and/or deeper, longer dives, then how do you stuff those dives into a dive table?

For example, 1st dive - 121' for 51 minutes, 1 hour surface interval ( SI ); 2nd dive 101' for 61 minutes, 2 hour SI; then at 10 minutes into the 3rd dive your dive computer stops working at 91'. What are you going to do on this dive?

What about dive #4 that is 2 hours after dive #3?

Please tell me how you can possible plug those dives into a dive table?

What if your dive computer is toast midway on a live-aboard trip?

It is a fair point but i did state that I thought the suggestion of 24hrs a bit much for NDL diving, so based on your scenarios even your first dive of 120+ ft for 51min is not a no deco dive, I don't even see how it is a recreational dive, i certainly can't stay at 120 for almost an hour on a single 80, at this point you should be diving 2 computers anyway (if you are intending to mean total run times then it wasn't clear and that's a different scenario entirely). If you are just on holiday and looking for a cost effective solution for redundancy I suggested the minimum I would use to feel comfortable. There are many variables and you can throw scenarios that will put a hole into every single dive plan a person can come up with. At the end of the day the op seemed like he was soliciting for different options and solutions to his described scenario and I provided him with one of many, it's up to each individual to do what they feel comfortable with and to remember that Internet advice is worth what you paid for it.

 

[Lorenzoid]

For casual recreational diving, I think having both an AI computer and an analog console on each dive is overkill and impacts streamlining. You only need so much redundancy on recreational dives before it becomes overkill. My thinking is that a diver should have the least amount of gear he can get away with safely. Computers are subject to failure, but it's uncommon enough that, on a recreational dive, it would not be much hassle to just call the dive and replace the failed computer with your analog console (or an SPG) until you can get the computer fixed. What's the big deal?

A backup computer carried on each dive would be ideal (that's what I do), but that wasn't your question.

 

[nv]

For casual recreational diving, I think having both an AI computer and an analog console on each dive is overkill and impacts streamlining. You only need so much redundancy on recreational dives before it becomes overkill. My thinking is that a diver should have the least amount of gear he can get away with safely. Computers are subject to failure, but it's uncommon enough that, on a recreational dive, it would not be much hassle to just call the dive and replace the failed computer with your analog console (or an SPG) until you can get the computer fixed. What's the big deal?

A backup computer carried on each dive would be ideal (that's what I do), but that wasn't your question.

Yeah I agree with a backup computer being ideal. That being said another computer would have to be AI.

If I don't get another AI I would definitely get an analog spg, which brings me to why I started this thread. Although I do recreational diving, it's on the deeper end. Would a combo be too much as opposed to a single spg? Granted it is a bit bulkier than an spg.

I have been thinking of getting another computer to mount on my wrist. Being that I have the puck air, should I just get the puck wrist since I'm used to it? What are your thoughts on having the same computer.

 

[Lorenzoid]

Yeah I agree with a backup computer being ideal. That being said another computer would have to be AI.

If I don't get another AI I would definitely get an analog spg, which brings me to why I started this thread. Although I do recreational diving, it's on the deeper end. Would a combo be too much as opposed to a single spg? Granted it is a bit bulkier than an spg.

I have been thinking of getting another computer to mount on my wrist. Being that I have the puck air, should I just get the puck wrist since I'm used to it? What are your thoughts on having the same computer.

My wife has an AI computer--Suunto Cobra 3. She wears a Suunto Zoop ($250, non-AI) wrist computer as a backup because we figure it runs the same algorithm, but it's generally not on her wrist; it's clipped to a BCD ring. She also owns a mini-SPG. (Nothing wrong with a larger one, but our goal is to minimize weight and volume of stuff we take when we travel.) If the Cobra 3 malfunctions (which it has not in over 100 dives), the plan is to end the dive, then swap out the Cobra 3 for the mini-SPG. She would do the next dive using the mini-SPG and the wrist computer. And we're both competent with tables if it ever comes to that.

 

[nv]

My wife has an AI computer--Suunto Cobra 3. She wears a Suunto Zoop ($250, non-AI) wrist computer as a backup because we figure it runs the same algorithm, but it's generally not on her wrist; it's clipped to a BCD ring. She also owns a mini-SPG. (Nothing wrong with a larger one, but our goal is to minimize weight and volume of stuff we take when we travel.) If the Suunto malfunctions (which it has not in over 100 dives), the plan is to end the dive, then swap out the Cobra 3 for the mini-SPG. She would do the next dive using the mini-SPG and the wrist computer. And we're both competent with tables if it ever comes to that.

I like that combo. I guess the main poin was that I got a $189 unit for $100 and wondering if I should change it to a mini-spg.

I know suunto runs the Rgbm, as does mares puck. What are your thoughts having two different computers that run same algorithm. I think suunto has its own modified Rgbm - I may be way off here.

The puck is about 175 and the zoop 250

 

[Lorenzoid]

I think you're correct. It's been said in other threads that Suunto's version of RGBM is proprietary, so we the public really can't be sure whether it's the same as another company's version of RGBM, and it most likely is not.

I don't think matching the backup with the primary is that critical. I'd rather dive with a backup computer that's not matched with my primary computer than not dive with a backup and all and be forced to resort to tables. I am lazy