Backup computer w/ different algorithm

[montyb]

I have a Oceanic Datamax Pro Plus for my primary computer - I also have my old Dacor Micro brain pro that I either wear on my wrist or put in my bc pocket. Never use it except if my oceanic were to die. Hasent happened so far.

montyb

 

[DareDevil]

It's simple, if they're not the same algorithm you follow the more conservative one. (I don't think you should even push the more conservative one to it's NDL.)
...[snip]...

Hi Damselfish,

What you said is very interesting. I totally agree about the fact a backup computer is useful because if your main one stops working, you can carry on the dive (or dives) with the second one, assuming you have a ... backup of the backup in the form of tables, depth meter, watch or bottom timer.

One question about which computer to follow: it is wiser to follow the "more conservative" as general norm, but it isn't a sort of hoxymoron?

I mean you said you are ready to carry on dive(s) with your back-up, so you must trust it, correct? Than at the same time you say it is better to trust the "more conservative", which I assume it is your primary unit.

But if one has the money to buy two computer, then why not buy two identical units with the "best" (I am using double quoting because it is extremely hard to say which computer has the best algorithms, at least for me) algorithm ?

I can see a lot of benefits because the diver does not have to adjust to a different user interface/alarms and the two computer will (or should) be always in synch

Cheers,

DareDevil

 

[jagfish]

Yes, your suunto will go into deco before your pelagic. Carrying them both on the same series of dives can result in some dramatic differences in available NDL time. Whether those differnces matter depends on the diving you are doing - you may not be getting close to deco on either computer anyways.

My suunto went into deco once when my oceanic showed 15 min NDL left...

Ditto on this. I know someone who dives with a Pelagic primary and Suunto backup. He never looks at the Suunto during the dive unless the Pelagic craps out. Echoing the point above, he is sometimes locked out of the Suunto because it went into deco in his pocket while the Pelagic was still within NDL.

I don't carry a backup, but if I did, I think it would be the same computer, or a cheaper version of the same manufacterer. I see no benefit to having the more conservative in your pocket. And if you have two and one is more conservative, presumably you will always be following that one anyway.

So if I had two, I would be relatively confident that they reacted identically to dive profiles and would only break out the backup if the primary failed.

 

[SeaFlea]

I use a Suunto Mosquito as my primary computer and my older Oceanic Prodigy as my back-up. I agree you should / must use the most conservative algorithm(SP) as your primary instrument so that neither will be violated. As to why not to follow the more liberal computer as many people use this computer solo? I look at it as a more conservative diving regiment for a mid 40's diver. I chose the Suunto as I felt it would be wise to be abit more careful in how much stress / exposure I subject my body to. I have seen moderate differences between the two NDL times as I can see them both throughout the dive. Typically the Oceanic allows me an extra 10 - 15 min (sometimes more) over the Suunto. Not a big penalty in my mind. Now where the Suunto will cut you very short as compared to the Oceanic is when you ascend faster than the Suunto likes it. Suunto's algorithm does watch your ascent rate carefully.

I like having a back-up computer and think its a good idea.

 

[Damselfish]

Hi Damselfish,

What you said is very interesting. I totally agree about the fact a backup computer is useful because if your main one stops working, you can carry on the dive (or dives) with the second one, assuming you have a ... backup of the backup in the form of tables, depth meter, watch or bottom timer.

One question about which computer to follow: it is wiser to follow the "more conservative" as general norm, but it isn't a sort of hoxymoron?


I mean you said you are ready to carry on dive(s) with your back-up, so you must trust it, correct? Than at the same time you say it is better to trust the "more conservative", which I assume it is your primary unit.



But if one has the money to buy two computer, then why not buy two identical units with the "best" (I am using double quoting because it is extremely hard to say which computer has the best algorithms, at least for me) algorithm ?

I can see a lot of benefits because the diver does not have to adjust to a different user interface/alarms and the two computer will (or should) be always in synch

Cheers,

DareDevil

Well, the reason to follow the more conservative one is not because you don't "trust" the other, but to avoid the very problem mentioned at the beginning of this thread - throwing one of the computers into violation. If you push the more liberal one and have the more conservative one in your pocket, and the liberal one craps out, that other one isn't a much of a backup if it's in your pocket thinking it's bent. Other way around pretty much avoids this problem.

I agree, if you're going to go the 2 computer route, it's probably better for them to be the same or at least similar for the reasons you mention. But sometimes circumstances make you wind up with different computers, like maybe you don't start out this way and buy them at the same time. For example, I have an older Suunto air computer which I wear on my wrist. I later bought a Vyper (console) because I wanted a Nitrox computer (not to mention a backup, a new toy and a new console. ) I follow the air computer even when I'm diving Nitrox, though I often push it to the edge which I wouldn't normally, since I can look at the Nitrox one and see what the "real" time is. So I'm getting a mixture of more conservatism and more time, and the Vyper is tracking O2. (If I'm diving air, I pay attention to the Vyper as it's air times are sometimes even more conservative than the older Suunto.) That said, I do plan to replace the air computer with another Suunto nitrox computer soon, though I may buy a cheaper Gekko rather than another Vyper. Similar interface and I think it's the same battery.

 

[wfmiller]

I dive with both a Suunto Cobra on a console and a Vyper on my wrist. I actually use them both during a dive. I like having a backup, like mentioned if something should go wrong with the one then I don't have to abort a dive or dives.

But lf I had 2 different brands then I would use the more conservative but that is what I would prefer personally.