owning multiple computers

[doctormike]

the zoop is pretty conservative and tells me no fly time but not sure about inert loading.

Tracking your inert gas loading is what a dive computer does, it is why you use one. Many of them have a "no fly" feature which is a simple countdown timer (generally set to 18 or 24 hours) that starts after you surface, but that's really not part of the dive computer itself. You don't need a dive computer to remember not to fly within that time frame.

At your level, I wouldn't complicate things by carrying two dive computers. Fiddling with algorithms to get the dive you want is a complicated and controversial discussion with MANY threads here... If you keep a fresh battery in your Zoop (which you know and love), it's pretty unlikely that it will fail, and in that worse case scenario, you might miss the second dive that day. Each computer has it's own menu tree, display preferences, etc... and having you learn two of them at this point seems unnecessary. eBay the i300 and spend that money on a couple of extra dives...

 

[rongoodman]

stupid question but how do i find out if its the same algorithm or get them to match up?

Both my Shearwater and back-up Liquivision X1 are running standard Buhlmann GF or VPM, so all I have to do is match the GFs or conservatisms. Otherwise, you're going to be stuck trusting what the manufacturer tells you. Buying two of the same model should work, different models from the same manufacturer might work.

 

[doctormike]

stupid question but how do i find out if its the same algorithm or get them to match up?

Just so you know, getting two computers with different algorithms to "match up" isn't as simple as it sounds, and if you drill down, not even really possible. Yes, you can play with the various factors that each computer allows so that they both show the same planned NDL for a given depth and mix at the start of a dive, but that doesn't mean that they will stay in sync throughout the dive. Different algorithms give different outputs based on the actual dive profile.

Long complicated topic, but the short answer is that with less than 50 dives (assuming your count is correct) and only a few dive trips per year, I would just use one computer and not deal with learning and following a second one, simply because you got one as a bonus. If you really like the i300 more than the zoop, then learn and carry that one, but nothing wrong with sticking with a computer that you already know...

 

[teknitroxdiver]

thanks, ok so is that set or can i get them to match?

You can't change the algorithm on these computers. So if you dive both, you just follow the limits of whichever one has less dive time remaining (almost certainly the Suunto).

One solution if you do want to have two might be to sell the i300 and get another Zoop. Then everything is identical. And I think it would be easy to do that swap with no extra cost.

 

[doctormike]

One solution if you do want to have two might be to sell the i300 and get another Zoop. Then everything is identical. And I think it would be easy to do that swap with no extra cost.

Why would a new rec diver carry two computers? I mean, there are some scenarios where that might help a bit, but they are pretty rare, and this isn't a standard recommendation from any agency that I know.

The fact that he has an item which can be sold for the cost of a second Zoop doesn't really change the analysis in my opinion. It would be the same discussion if we told him to sell a set of golf clubs to buy a second dive computer...

 

[teknitroxdiver]

Why would a new rec diver carry two computers? I mean, there are some scenarios where that might help a bit, but they are pretty rare, and this isn't a standard recommendation from any agency that I know.

The fact that he has an item which can be sold for the cost of a second Zoop doesn't really change the analysis in my opinion. It would be the same discussion if we told him to sell a set of golf clubs to buy a second dive computer...

It's a minor investment to hedge against a failure causing a missed dive or two. Similar to traveling with an extra first stage. I probably wouldn't suggest that he go out and buy a computer outright to do this, but since he already has it it's as simple as throwing the spare in a pocket or on the other wrist and going diving. I agree that it's not a huge benefit either way, but if he's already got it and doesn't need the cash, there's no harm. Swapping out for a matching Zoop would be icing on the cake.

 

[BoltSnap]

I don't see the problem with having a backup computer especially and specifically since the OP is a traveling diver and losing a day of diving, or even a single dive, due to any computer downtime is very costly. This cost for missing a dive during a dive vacation may probably be more expensive than the cost of the backup computer. Computers do fail or stop working for several reasons including unexpected battery failure just like any other piece of dive equipment. They may also experience erratic behavior due to component malfunction or due to faulty design. No brand or model is immune to failure, it may differ in probability only.

There is merit to having two different computers from two different manufacturers with different algorithm/software as backup for each other to help reduce the risk of two similar computers from the same manufacturer both failing or behaving erratically at the same time due to component batch issues or faulty programing. Having different computers from different manufacturers not helps in case of one computer failure but also provide indication to the diver in case there is a system software issue that may not be very clear if one of two computers are of the same make and model.

 

[Steve_C]

I do not want to loose dive 2, or have to cut dive 1 short due to computer failure.
Typically I am not diving the next day.

For historical reasons I have a zoop (bought in an emergency situation on a trip) and a second different computer. Have watched the two on a lot of dives. They are essentially the same on dive 1. Zoop is more conservative on dive 2.

Clear both on dive 1. On dive 2 depending on depth the other computer may have 10 minutes or more NDL. Depending on the dive, dive number 2 is on the zoop, OR number 2 is on the other computer but I clear the zoop, OR number 2 is on the other computer with an extra long safety stop but zoop not quite cleared and I am not diving the next day.

Note that if other computer dies while zoop is in NDL I dive the zoop. If other computer dies when zoop is in mild deco, I immediately go up and clear the zoop on the way and at the hang bar. I know from experience that this would actually have me within NDL on the other computer. Note that this scenario only happens when I am spending some extra time looking at stuff within close proximity to the anchor line so immediate ascent is always possible.

Not for all but what I do if my computers are determing things.

People I dive with regularly have large tanks, dive nitrox mixes richer than I do, and are good on air. Of course if a buddy needs to go up because of NDL on his computer we go up.

 

[doctormike]

It's a minor investment to hedge against a failure causing a missed dive or two. Similar to traveling with an extra first stage. I probably wouldn't suggest that he go out and buy a computer outright to do this, but since he already has it it's as simple as throwing the spare in a pocket or on the other wrist and going diving. I agree that it's not a huge benefit either way, but if he's already got it and doesn't need the cash, there's no harm. Swapping out for a matching Zoop would be icing on the cake.

Gotcha. I agree that it's good not to miss a dive.

Just to be clear, are we recommending that all new open water rec divers have two computers for this reason, as an insurance policy against a missed dive? That's fine if you feel that way (I don't, but it's certainly a defensible and reasonable suggestion). If that isn't your standard recommendation, why is the OP different, especially if you are suggesting that he sell the computer and buy a second Zoop? Should every new diver asking for computer recommendations be told to buy two computers?

 

[teknitroxdiver]

Gotcha. I agree that it's good not to miss a dive.

Just to be clear, are we recommending that all new open water rec divers have two computers for this reason, as an insurance policy against a missed dive? That's fine if you feel that way (I don't, but it's certainly a defensible and reasonable suggestion). If that isn't your standard recommendation, why is the OP different, especially if you are suggesting that he sell the computer and buy a second Zoop? Should every new diver asking for computer recommendations be told to buy two computers?

I would put it under the "not a bad idea" heading. The OP may have 50 dives now, but he says he plans to do over 100 dives per year with up to 4 dives a day, and is pursuing at least some amount of advanced certifications (deep). That's not your average one-week-in-Mexico vacation diver. So, yes, if a newer diver expressed those circumstances, I would suggest it if it's within their means.

As for selling it for a Zoop, the only reason for that is to make both computers the same. And non-Novo Zoops are so cheap it probably wouldn't cost anything extra to make the change.