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MnM_Divers
06-09-2009, 13:34
If using a wireless AI computer is there any reason you couldn't keep a set of analog gauges attached to one of the high pressure ports and the wireless transmitter connected to the second hp port? I realize this adds a hose and offsets some of the advantage of using wireless but it also seems like it would be nice to have the redundancy in case of issues with the AI computer.

MSilvia
06-09-2009, 15:42
If that makes sense to you, go for it. As an alternative, you could go without, and just abort the dive if the AI fails. So long as you don't try to continue the dive without knowing how much gas you have, you shouldn't need to treat it as a major crisis. Just keep a buddy close during ascent in case you need to share.

MnM_Divers
06-09-2009, 16:25
Thanks for the reply. I suppose computer reliability probably makes this overkill, I was just wondering if anybody else did this.

The Great Kazoo
06-09-2009, 16:31
I do ONLY if I am diving deep (or solo)..and or..(with Dbls). I use a back up computer as well as an Analog. But, diving Rec, I just use my AI and Back Up Computer..

MSilvia
06-09-2009, 16:45
Thanks for the reply. I suppose computer reliability probably makes this overkill, I was just wondering if anybody else did this.
I wouldn't think of it in terms of whether or not it's overkill, but in terms of what you hope to accomplish with it, and if the cost is justified. In other words, how much is it worth to you to be able to continue a dive in the unlikely event of a computer failure? If you're on a liveaboard, it might be worth quite a bit to have a backup. If it's thirty minutes into a shore dive that's 1/4 mile from a LDS, maybe not so much.

plot
06-09-2009, 16:56
It's not an uncommon setup, so go for it.

As MSilva pointed out though, if something fails, you generally abort the dive... so unless you're in an overhead environment, it doesnt add much of a safety factor.

MnM_Divers
06-09-2009, 17:20
I was mainly thinking that it may be nice to have gauges to keep diving if you're out on a dive boat doing multiple dives and your computer crapped out on the first dive, not so much for continuing a single dive. I agree that it would be best to abort the dive when the failure occurs. I am a relatively new diver and my wife has 40+ dives but most were in the early 90's. We were discussing various situations/setups and I appreciate the feedback.

plot
06-09-2009, 17:26
If your computer craps out and you havnt been paying attention to your guages (and don't have a bottom timer on top of all that), how will you know how much bottom time you have for the second dive? ;)

comet24
06-09-2009, 18:39
I would worry about it. In the unlikely event your computer fails it time to abort the dive anyway.

UofTOrange
06-10-2009, 08:22
My limited experience advice would seem to coincide with others here. It would be nice to have in the boat diving scenario. You would just call the first dive then dive with the gauges for the others. Otherwise, it really seems to defeat the point of the AI computer to me

chilly willy
06-10-2009, 09:00
You could just carry the SPG in your SAD kit in case you are out on a boat and the computer goes south and you still want to continue on subsequent dives. If the computer quits while diving just abort the remainder of the dive.

MSilvia
06-10-2009, 09:44
You could just carry the SPG in your SAD kit in case you are out on a boat and the computer goes south and you still want to continue on subsequent dives. If the computer quits while diving just abort the remainder of the dive.
I was thinking that, but it probably makes more sense to just hook it up if you have the spare HP port, so you don't have to abort in the first place.

obrules15
06-10-2009, 10:31
I always have an SPG available when using an AI, I don't add it on to my setup I just have it in my bag with the requisite tools to change it out in the event of a failure.

MnM_Divers
06-10-2009, 13:19
My wife is almost always my dive buddy and we generally stick pretty close so depths and bottom time from the first dive would be available unless she had a failure as well, at which point it is probably time to give it up for the day. Keeping the gauges as part of the SAD kit is certainly an option that would probably work just as well for the senario I was discussing. Thanks.

Byte Me
06-10-2009, 13:47
When I first bought my computer (Oceanic VT3) I was curious about redundancy as well. I called Scuba Toys and talked to either Larry or Joe explained where I was in my dive "life" and where I expected to be diving. Their response - "If your computer craps out you abort anyway - why spend the extra $$ if you don't need to". Since then I've discovered that I really really love diving and want to do it more so I'm thinking of getting an SPG because I now have a depth gauge and bottom timer on my dive watch so I wouldn't necessarily have to abort a dive and could make subsequent dives in the day.

I do believe I'm going to go that route and get an SPG, HP Miflex hose and try to stay as streamlined as I intended from the start which is why I went AI in the first place. If you don't care about extra hoses you may not have gone AI to begin with just to avoid the cost of it.

plot
06-10-2009, 15:53
As I was alluding to earlier, without a proper depth guage and without timing your dive, having a backup SPG is useless if your computer fails unless you wait 24 hours before jumping back into the water. Otherwise, how are you going to do your tables to figure out your bottom time?

obrules15
06-10-2009, 16:08
I always have an SPG available when using an AI, I don't add it on to my setup I just have it in my bag with the requisite tools to change it out in the event of a failure.


As I was alluding to earlier, without a proper depth guage and without timing your dive, having a backup SPG is useless if your computer fails unless you wait 24 hours before jumping back into the water. Otherwise, how are you going to do your tables to figure out your bottom time?

Sorry, I should have added to my post -- I always dive with a backup wrist computer so in event of failure I only need SPG.

MnM_Divers
06-10-2009, 16:51
As I was alluding to earlier, without a proper depth guage and without timing your dive, having a backup SPG is useless if your computer fails unless you wait 24 hours before jumping back into the water. Otherwise, how are you going to do your tables to figure out your bottom time?

Since my wife I are always dive buddies she would have the dive time and using the max. depth and tables would be pretty conservative relative to the computer. Obviously if there was any significant differences in our dive profile that would need to be accounted for or future dives would be aborted.

rawalker
06-10-2009, 18:51
Redundancy is a matter of risk management given the type of diving you are doing.
Yes for a single dive in open water failure of the computer is fairly simple to manage by aborting the dive but this may not be the only impact to your day of diving. Unless you have an alternate means of checking your depth and bottom time you may be done diving for 24 hrs.
In this case using gauges and a dive watch may allow you to continue diving using tables.
For this reason I keep multiple backups with me on all but local dives.
I use an Atom 2.0 on my wrist as my primary with an Atom 1.0 on my shoulder D-ring. I keep an extra transmitter in my save a dive kit along with extra batteries. If a computer fails I do keep a gauge set in my reg bag, my everyday Casio sports watch is 200m rated and tables are in my log book.
I'd hate to be on a nice trip and need to miss a dive that I did have to.

Splitlip
06-10-2009, 21:24
As I was alluding to earlier, without a proper depth guage and without timing your dive, having a backup SPG is useless if your computer fails unless you wait 24 hours before jumping back into the water. Otherwise, how are you going to do your tables to figure out your bottom time?
Quite correct Plot. I have not embraced the AI computer yet. neither hoseless or hard wire. The hoseless seems cool to have everything in one place, but I handled that by moving my brass and glass to my left should d-ring when my hands are occupied.

People say the feature of telling you bottom time remaining based on psi is priceless. But how doe it know if you are diving an lp 120 or an al 60. Maybe you can program tank volume~pressure. I don't know, nor do I think that is a crucial function.

I have had 4 computer failures in 10 years. I have no need to thumb a dive. I wear either 2 computers or a watch with dive timer and depth gauge. If I wear the watch, I have tables in a pocket.

sooooo to answer the OP. I would dive with an SPG which as he stated kind of negates one of the bennies of the AI. Then he should also carry 2 computers or a computer and dive timer, depth gauge and tables. Other wise he is still thumbing the dive if the AI fails even with the back up spg.

I say keep it simple. As I said, my SPG ios on my hip or shoulder. My computer(s) and/or dive timer are on my wrists. "whewww":smiley36: TMI

Splitlip
06-10-2009, 21:32
Redundancy is a matter of risk management given the type of diving you are doing.
Yes for a single dive in open water failure of the computer is fairly simple to manage by aborting the dive but this may not be the only impact to your day of diving. Unless you have an alternate means of checking your depth and bottom time you may be done diving for 24 hrs.
In this case using gauges and a dive watch may allow you to continue diving using tables.
For this reason I keep multiple backups with me on all but local dives.
I use an Atom 2.0 on my wrist as my primary with an Atom 1.0 on my shoulder D-ring. I keep an extra transmitter in my save a dive kit along with extra batteries. If a computer fails I do keep a gauge set in my reg bag, my everyday Casio sports watch is 200m rated and tables are in my log book.
I'd hate to be on a nice trip and need to miss a dive that I did have to.

:smiley36: And my buddies call me BATMAN. I'm gonna guess yours is bigger than mine (save a dive). I don't keep a gauge set, but I keep an extra 2nd stage on an octo length hose.

(sorry for the hi jack)

UCFKnightDiver
06-11-2009, 08:22
It's not an uncommon setup, so go for it.

As MSilva pointed out though, if something fails, you generally abort the dive... so unless you're in an overhead environment, it doesnt add much of a safety factor.

I wouldnt say it really adds a saftey factor in a overhead either if using 1/3rds you should have plenty of gas to get out.

thor
06-11-2009, 10:32
If you don't have a pressure gauge attached, it is a good idea just to have a spare gauge in your spare parts bag, that way if your air integrated computer fails on one dive, at least you still have a pressure gauge for the next dive.

rawalker
06-12-2009, 04:02
People say the feature of telling you bottom time remaining based on psi is priceless. But how doe it know if you are diving an lp 120 or an al 60. Maybe you can program tank volume~pressure. I don't know, nor do I think that is a crucial function.


The computer doesn't need to know the tank size the computation is based on rate of consumption, depth and tank pressure.

Oh, and my save a dive kit has an extra 2nd stage also.