owning multiple computers

[Antmany2k]

If you want to do the kind of diving that really needs two computers then one of them probably wants to do more than one gas.

The zoop does nitrox. As for the aqualung i think i will sell it. The consensus seems to be i dont need a 2nd and if i do it should be same make as my primary

 

[doctormike]

If you happen to bend one then dive the other.

Not sure that this is good advice for a new diver!

 

[Antmany2k]

Don't worry doc im not bending anything

 

[stuartv]

What is the reasoning for saying that diving with 2 computers means they should have the same or matching algorithms? I don't see any reason for that at all. Especially if the OP is comfortable following the more conservative one (which, as has been said, is probably going to be the Zoop).

I'd say all the OP needs to learn how to do is set the FO2 on both computers, so when he does dive, he can have both set correctly for the gas he's using, so they'll both correctly track his inert gas tissue loading.

I definitely don't feel like diving with 2 computers is dangerous or anything where I would tell someone "you shouldn't dive with 2 computers because it's too risky for your experience level." Has anyone here ever heard of any diving accident ever that stemmed in any way from a diver having 2 computers?

If you plan to dive more than 1 dive per day, then you can choose to dive with 1 computer or 2. If your computer dies during dive 1 and you aren't wearing a backup, then (if you follow your training) you will end your dive and, if you choose to dive again within 24 hours, you will have to try and figure out your max depth and your total dive time of dive 1 from your buddy and then dive tables. That means your next dive(s) will likely be much shorter than if you had been carrying a backup computer. And you'll still have to buy, rent, or borrow another computer or bottom timer to use.

If you dive with 2 computers and 1 dies during dive 1, you continue with your dive and any subsequent dives, with no change in plans. If both of them die, well, then you're back to diving with tables.

Whether any individual chooses to dive with 2 computers is totally a personal decision that has to be based, at least in part, on how important it is to them to have their dives be uninterrupted and to not have to cut subsequent dives short because of planning using tables.

My personal risk/reward/cost/benefit analysis is that if I have flown somewhere for a vacation that involves any amount of diving, I will take and use 2 computers, so that I can be pretty darn confident my diving plans will not be cut short in any way because of a computer problem. If I have 2 computer problems, well, then I'll be screwed, at least to some degree.

@Antmany2k: I would keep and dive both. You might even find that once you get used to it, you prefer the AL and want to sell the Zoop and replace it with a different backup - maybe one that has an algorithm matching the AL or maybe even one that is a bit more liberal.

 

[RainPilot]

I raised the "matching " issue first here, mostly to prevent frustration when you are diving 2 very different algorithms. If you adjust conservancy on them till they kinda resemble each other then it's a little less annoying in the long run.

Not absolutely necessary to be identical just close-ish.

 

[doctormike]

What is the reasoning for saying that diving with 2 computers means they should have the same or matching algorithms?

The purpose of the OP carrying a dive computer on a rec dive is to track N2 loading and say when it is time to ascend, based on an algorithm that is chosen either after careful study or because it's the one that they have. The purpose of carrying a second computer is redundancy - you can continue to dive if one computer fails. Why would a new rec diver want two computers telling him different things?

I'd say all the OP needs to learn how to do is set the FO2 on both computers, so when he does dive, he can have both set correctly for the gas he's using, so they'll both correctly track his inert gas tissue loading.

How can they both be correct if they are doing different calculations based on different theories of decompression? They can both be generating a safe ascent profile within an acceptable margin of error. But this statement implies that there is some gold standard "true" tissue loading that different computers compete to accurately measure.

I definitely don't feel like diving with 2 computers is dangerous or anything where I would tell someone "you shouldn't dive with 2 computers because it's too risky for your experience level." Has anyone here ever heard of any diving accident ever that stemmed in any way from a diver having 2 computers?

C'mon, Stuart... it's OK to give people advice on how to do things without the old "you're gonna die" meme!

Whether any individual chooses to dive with 2 computers is totally a personal decision that has to be based, at least in part, on how important it is to them to have their dives be uninterrupted and to not have to cut subsequent dives short because of planning using tables.

My personal risk/reward/cost/benefit analysis is that if I have flown somewhere for a vacation that involves any amount of diving, I will take and use 2 computers, so that I can be pretty darn confident my diving plans will not be cut short in any way because of a computer problem. If I have 2 computer problems, well, then I'll be screwed, at least to some degree.

Right, I agree. I don't thing that it's a standard recommendation for new divers, but if you have the money it's reasonable to carry a second computer so that you won't miss dives if one of them fails.

 

[stuartv]

I raised the "matching " issue first here, mostly to prevent frustration when you are diving 2 very different algorithms. If you adjust conservancy on them till they kinda resemble each other then it's a little less annoying in the long run.

Not absolutely necessary to be identical just close-ish.

I don't see a need or even a real advantage to that. It might actually be good to keep the more liberal computer on its default settings, just so you can start to develop a sense of how conservative the more conservative computer really is. If they stay close, cool. If you start seeing a trend that the conservative computer is really cutting into your bottom time, that would be data to support a decision to sell the more conservative computer (assuming you want to start having longer bottom times).

I'm a bit OCD. I dive with two different computers, but if they are both set to the same GF, then I want them to show really dang close results. But, if I were diving 2 computers with different algorithms, I would not find it frustrating that they show different results. Though I might start to feel frustrated if I were consistently ending my dives when the more liberal computer was still showing lots of NDL left. But, that's a good thing to learn, not a reason to set the computer to be extra conservative. To me, anyway.

 

[RainPilot]

We are on the same page, I was thinking more of making the "dive-ender" more liberal since I would always obey the limiting DC. (Really don't need a lockout on a dive vacation, kinda defeats the object of having two).

 

[stuartv]

The purpose of the OP carrying a dive computer on a rec dive is to track N2 loading and say when it is time to ascend, based on an algorithm that is chosen either after careful study or because it's the one that they have. The purpose of carrying a second computer is redundancy - you can continue to dive if one computer fails. Why would a new rec diver want two computers telling him different things?

For the same reason an old tech diver would want it? So it's there in case you need to look at it.

How can they both be correct if they are doing different calculations based on different theories of decompression?

So, the AL is correct if you're only using that, but it's wrong if you also carry the Zoop with you?

They can both be generating a safe ascent profile within an acceptable margin of error. But this statement implies that there is some gold standard "true" tissue loading that different computers compete to accurately measure.

Well, that would be wrong and if you interpreted my statement that way, well, it wasn't what I meant. There is a gold standard "true" method of recording the depth and time and gas being used. Both computers should do that accurately and the same. What they calculate after that is up to each computer. But, the point is that if you do what I said (set both to the correct FO2 and dive with both), then either one can die and you can go on with dive #2 with the one that is still working. And it will correctly calculate your NDL and ascent based on its algorithm (unless it dies, too). If you don't take both on dive #1, then whichever one stayed on the boat cannot correctly calculate your NDL for dive #2 (if it's within 24 hours).

C'mon, Stuart... it's OK to give people advice on how to do things without the old "you're gonna die" meme!

Fair enough. But, "you're gonna die" was really implied by someone else when they told antman that, with his number of dives, he shouldn't carry 2 computers. At least, that's how I took "I wouldn't complicate things by carrying two dive computers." It's one more complicated before you get in. It's really not any more complicated after you get in. If you're really worried about it, you could suggest that he stow the extra computer in a pocket of his suit or BCD, so he can't even see it during the dive.

 

[Basking Ridge Diver]

stow the extra computer in a pocket of his suit or BCD, so he can't even see it during the dive.

Which is what I do - I just don't see a need for both on my arm(s) - one more thing to bump or scratch while I am reaching into a hole for a lobster...
But I am not doing deco - so maybe I would feel differently then....