Advice needed about backup computers

[psychocabbage]

get another IQ 700? I have 5 of them.

Whats better to backup a unit? The same unit again! Same download cable works..

 

[Coldwater_Canuck]

Computers as any other equipment can fail; so a little redundancy won't hurt... I won't recommend you buying another model of dive computer though. Different models have different algorithms so distinct NDL and/or deco profiles, so if you use two different dive computers, which one should you follow? Which one is right?

Is it really a backup if you're having to decide which one to use?

The way I see it is you'd use your primary and only your primary, unless your primary dies then you use your backup. Sure the algorithms may not be the exact same, and moving to your backup may make you more conservative or liberal, but as long as you trust both, I don't see this as a big deal.

When my current computer becomes a backup, I make sure the batteries are charged and the settings are right for the dive (Nitrox, salt water, etc.), stick it in my BCD pocket, and forget about it unless I need it.

 

[paddler3d]

DR Nitek Duo?

 

[rmc77]

Is it really a backup if you're having to decide which one to use?

The way I see it is you'd use your primary and only your primary, unless your primary dies then you use your backup. Sure the algorithms may not be the exact same, and moving to your backup may make you more conservative or liberal, but as long as you trust both, I don't see this as a big deal.

When my current computer becomes a backup, I make sure the batteries are charged and the settings are right for the dive (Nitrox, salt water, etc.), stick it in my BCD pocket, and forget about it unless I need it.

What you do when your backup starts to "scream" because it thinks you're missing a deco stop or a NDL?? Do you stick with your primary, even though your backup may freeze and become useless for at least 24 hours??

 

[Coldwater_Canuck]

What you do when your backup starts to "scream" because it thinks you're missing a deco stop or a NDL??

The "warnings" are useless for me , the neoprene blocks my ears. And you can normally disable them.

Do you stick with your primary, even though your backup may freeze and become useless for at least 24 hours??

Mine only goes into "gauge only" mode after a "runaway" ascent, not for missing a safety stop, not sure about others. It also allows you to reset it. But I think doing deco could be a whole other story, I'm just talking recreational (which I believe the OP was).

 

[rmc77]

The "warnings" are useless for me , the neoprene blocks my ears. And you can normally disable them.


Mine only goes into "gauge only" mode after a "runaway" ascent, not for missing a safety stop, not sure about others. It also allows you to reset it. But I think doing deco could be a whole other story, I'm just talking recreational (which I believe the OP was).

If it goes into gauge mode, it's not a full dive computer anymore...without dive tables it will be useless. But not all dive computers do that; some will just leave you with an ERROR screen for at least 24 hours. Nevertheless, in both cases you'll face a decision of following or not following the backup computer... So what happen if your backup is in error or in gauge mode 'cause you choose not follow its advices (or screaming beeps) and now your primary stops working?? FYI, some computer algorithms can give you 3-4 more NDL minutes than others (some even more)... so, if you consciously choose a more forgiving computer as the backup, you should be ok in a square profile but can you guarantee they will behave the same in a multilevel dive? I sincerely cannot.
To avoid all that is why I recommended using the same computer as backup, if the OP chooses to use computers for redundancy… I personally think that having two computers are an unnecessary waist of money, only one computer and a bottom timer (or a good dive watch) with tables are more than enough… but that’s a personal opinion.

 

[ivobj]

I know this probably not the most common, but I will tell what I do... the computer is my backup, I use primarily a the Uwatec digital bottn timer and depth gauge. Not having all the functions of the computer it is relatively cheap. If you prefer to use computer as primay you can use the botton timer as backup. Of course you must know NDLs (you can memorize and for safety write in your slate), and recalculate your dive based on tables.

The reason I use botton timer as primary is because it forces me to plan my dives.

 

[Splash-X]

Well said BJ

Any computer user should be checking their dive planning mode on their computer before entering the water regardless. This will allow both you and your buddy to talk about "How Long" and "How Deep", part of the key elements of the dive plan

 

[rmc77]

I know this probably not the most common, but I will tell what I do... the computer is my backup, I use primarily a the Uwatec digital bottn timer and depth gauge. Not having all the functions of the computer it is relatively cheap. If you prefer to use computer as primay you can use the botton timer as backup. Of course you must know NDLs (you can memorize and for safety write in your slate), and recalculate your dive based on tables.

The reason I use botton timer as primary is because it forces me to plan my dives.

Maybe it's not that common, but that's the way I do too

 

[Coldwater_Canuck]

If it goes into gauge mode, it's not a full dive computer anymore...without dive tables it will be useless.

As I said in my last post, it only enters this mode on a runaway ascent: meaning you fly to the top, I think it takes like 30 feet of ascending over 60 feet per second or something. Nothing else will lock you out. I can't imagine other computers locking you out for your safety stop.

FYI, some computer algorithms can give you 3-4 more NDL minutes than others (some even more)... so, if you consciously choose a more forgiving computer as the backup, you should be ok in a square profile but can you guarantee they will behave the same in a multilevel dive? I sincerely cannot.

If you don't trust one of the computers, that's obviously an issue (it's too liberal for you, etc.). However, if you'd be comfortable diving either one of the computers, I dont see why it matters if you switch mid-day as long as both were running.

To avoid all that is why I recommended using the same computer as backup,

I don't think it's a bad idea at all (if anything, it will be less stuff to learn). However, if I end up spending $600 on a dive computer, no way I spend it again for a backup.