Sorry to be picky but you actually said "I would sit a dive out, if necessary," not 'a dive' 'if necessary'. This may be many dives and if repetitive will be necessary. The reason I pick on this is to ensure newer divers don't think it is okay just to sit out one dive.
Considering second/backup dive computer
- Thread starter rprice54
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Sorry to be picky but you actually said "I would sit a dive out, if necessary," not 'a dive' 'if necessary'. This may be many dives and if repetitive will be necessary. The reason I pick on this is to ensure newer divers don't think it is okay just to sit out one dive.
AdivingBel
Diver
If I wasn't concerned with clearing nitrogen from my system, why would I sit out a dive at all? I fully understand the concept, and if new divers didn't get that, I apologize. If that is your only message, I applaud it, but in my reply I made that very clear. Now it just seems you want to take me to task to show YOUR knowledge. I don't see how that is very helpful or productive. IMHO. Safe diving.
eelnoraa
Contributor
I agree with tbar here. If you intend to have a backup, you may want to think about these options:
- whether you want to bring that with you on every dive, so that when the main breaks down during a dive, you have a backup. You back up will have the same profile, same diving history as your main. In this case, you want your backup to be exactly the same as your main, so that you backup won't get into deco and lock you out in case you need to use it. Or you back up to be in gauge mode and you have some knowledge about using tables.
- if you don't carry the backup on your dive and live it on the boat/shore, you will have to abort the dive when the main breaks down. Then you have to figure out how many dives you want to sit out before you can jump in again with your backup.
Personally, I would use back up in gauge mode and use table for the rest of the dive if needed. I think everyone should have knowledge of using table and the concept behind it. Even if you use DC, you should somewhat know what the DC is trying to do. Blindly trust the DC for that NDC time is just nut.
- whether you want to bring that with you on every dive, so that when the main breaks down during a dive, you have a backup. You back up will have the same profile, same diving history as your main. In this case, you want your backup to be exactly the same as your main, so that you backup won't get into deco and lock you out in case you need to use it. Or you back up to be in gauge mode and you have some knowledge about using tables.
- if you don't carry the backup on your dive and live it on the boat/shore, you will have to abort the dive when the main breaks down. Then you have to figure out how many dives you want to sit out before you can jump in again with your backup.
Personally, I would use back up in gauge mode and use table for the rest of the dive if needed. I think everyone should have knowledge of using table and the concept behind it. Even if you use DC, you should somewhat know what the DC is trying to do. Blindly trust the DC for that NDC time is just nut.
K
KeithG
Guest
You find the hard core divers here, so having a backup is likely much more common on SB than in the general scuba population. I imagine there is a significant percentage of divers that do not even own a computer.
We go on "dive vacations" as opposed to "vacations that include some diving". For us a backup computer is considered essential to prevent unwanted down time on a liveaboard.
As already noted, it makes sense for the primary and backup to either be the same or run the same algorithm. Ours are all "the same". We use old school Uwatec Aladins and the cost of used backup computer is insignificant ($35 to $70 on ebay). For us, cost is not an issue.
Damselfish
Contributor
A backup computer that doesn't go diving with you all the time isn't really a backup - it's a spare. Having the backup in gauge mode (if it even has it) loses a lot of the benefit of having a backup computer. Perhaps you can get your data out of it and figure out where you are on the tables, but if you've been diving lots the tables will probably suggest you're dead. And at least some computers I don't think you're able to change out of gauge mode right away, so you still wouldn't have a "computer" to use from then on.
We have also bought most of our current computers used. I'm sometimes tempted by shiny objects, then I just go buy something on eBay or wherever. One of these days the shiny object will probably win.
We have also bought most of our current computers used. I'm sometimes tempted by shiny objects, then I just go buy something on eBay or wherever. One of these days the shiny object will probably win.
seaseadee
Contributor
I just purchased the Subgear XP3H as my backup to my oceanic VT4. I've had pains with my oceanic and I needed to get a backup. It's about the size of an SPG with a boot on it, so it clips off to my hip D-Ring and I can forget about it. I was very impressed with the User Interface as it only took one quick read through the manual to figure out what I needed.
XP-H On Leisure Pro
XP-3H On Liesure Pro
XP-H On Leisure Pro
XP-3H On Liesure Pro
Ignore the Petrel haters. They are just jealous. 
If I understand you correctly you potentially need two computers. One for your son and a backup for you. Either way, and if you son will mostly be diving with you, it is helpful to have computers with similar algorithms. Or at the least you will need to use the least conservative computer as your backup, otherwise you risk putting it in deco and depending on the computer, in lockout mode. Then it will be useless to you until it clears.
An Oceanic or other "liberal" computer would work as backup to your Zoop if you can't match computers. I can't imagine a dive scenario that a Zoop would accept but not a computer set for DSAT. A second alternative would be a dive computer similar to the Geo that has multiple algorithm setting. You can then select the algorithm and SF/CF to more closely match dive buddies or your primary dive computer.
I think you will find though that having your primary computer on console and wrist computer as backup will be less than ideal.
Third option is to give the Zoop to your son as you mentioned then buy two similar computers for yourself, a console and wrist mount. This would probably be the simplist and in the long run the cheapest and least confusing option.
If I understand you correctly you potentially need two computers. One for your son and a backup for you. Either way, and if you son will mostly be diving with you, it is helpful to have computers with similar algorithms. Or at the least you will need to use the least conservative computer as your backup, otherwise you risk putting it in deco and depending on the computer, in lockout mode. Then it will be useless to you until it clears.
An Oceanic or other "liberal" computer would work as backup to your Zoop if you can't match computers. I can't imagine a dive scenario that a Zoop would accept but not a computer set for DSAT. A second alternative would be a dive computer similar to the Geo that has multiple algorithm setting. You can then select the algorithm and SF/CF to more closely match dive buddies or your primary dive computer.
I think you will find though that having your primary computer on console and wrist computer as backup will be less than ideal.
Third option is to give the Zoop to your son as you mentioned then buy two similar computers for yourself, a console and wrist mount. This would probably be the simplist and in the long run the cheapest and least confusing option.
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Could I suggest, as another option, you both take a min deco course. No computer required just a timing device and a depth guage. No sharing, no lock out , simple and easy.
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Sent from my iPhone using Tapatalk
ajduplessis
Contributor
Give the Zoop to your son and buy a Petrel. I would also not bother with a backup if Petrel is used for rec dives, they don't fail and batteries are user replaceable and they use any AA battery type. If you really require a backup rather buy a bottom timer instead. If you go down the tec route you just add a slate.
If you have to use two computers make sure they are the same brand and operate the same.
Try to avoid getting confused with different screen layouts, button operations and algorithms.
When you dive on shallow reefs you do not need more than one computer. If you're diving within the ND Limits and your computer fails and you do not have a backup you can simply ascend slowly and do a safety stop for a few minutes before getting out of the water.
I have used two identical computers in the technical realm for years and recently replaced one of the two with a simple bottom timer and slate with the necessary deco plans. The verdict is still out on what works better. I find slates with plans better when diving in teams as everybody has a common goal and plan.
My advice is simple: Give the Zoop to your son and buy a Petrel. You can leave it in Rec mode if you're not going to use it for technical diving. I don't believe that you need more than one computer for NDL sport diving.
Try to avoid getting confused with different screen layouts, button operations and algorithms.
When you dive on shallow reefs you do not need more than one computer. If you're diving within the ND Limits and your computer fails and you do not have a backup you can simply ascend slowly and do a safety stop for a few minutes before getting out of the water.
I have used two identical computers in the technical realm for years and recently replaced one of the two with a simple bottom timer and slate with the necessary deco plans. The verdict is still out on what works better. I find slates with plans better when diving in teams as everybody has a common goal and plan.
My advice is simple: Give the Zoop to your son and buy a Petrel. You can leave it in Rec mode if you're not going to use it for technical diving. I don't believe that you need more than one computer for NDL sport diving.
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