Considering second/backup dive computer

[rprice54]

I'm considering a new dive computer. All of my diving is recreational, I don't see me getting into complicated/technical stuff any time soon. I have my AOW/Nitrox cards. I currently have a console mounted zoop which, while basic, has served me well and does what I need it to do. But I'm also interested in having a backup/alternate computer. I went on a recent trip to San Salvador, and had a great time, but we were in the middle of nowhere, doing multiple deep dives every day. If my zoop went out or had a dead battery I would have been stuck. Resorting to Dive tables would have cut me out of several dives, not really an ideal option when you've spent $$$ to get out there.

Plus my son just got his Jr OW card, so we'll be taking trips and will need another computer at some point. I'm thinking about getting a wrist worn computer. When it's just me diving, I'd use the wrist and keep my zoop as a backup, but when it's the two of us he can take the zoop and I'll use the wrist. For the time being all of his dives are going to be relatively shallow anyways. I could just buy him a cheapo $200 computer for himself, but I'd rather spend a little more on my gear and hand down the Zoop.

Of course, the wife goes- "You already have a computer, why do you need another?"

Just curious how many of you guys/gals are diving with a backup computer? Is that common practice or are they reliable enough most folks forgo it? I do carry an analog depth gague in my BC pocket as an emergency backup in case the computer goes caput, I can still use it for max depth/ ascending/safety stop, etc. and tables if absolutely necessary.

It looks like there are a few Oceanic OCS still floating out there with a decent discount since they've been discontinued for the AI version, I really have no need for AI. My SPG works. I've read where they can be a little wonky, so I don't think I'd ever forgo the SPG even if I had AI. I'd probably get the OCS or Geo. Unfortunately my LDS only carries Suunto D4i and D6i (small town in the middle of a landlocked state, not a ton of dive shops around) and I'm just not ready to spend $800+++ for a wrist computer.

 

[ronscuba]

Buy 2 Petrel's. 1 for your main computer, the 2nd as a backup. Use the Zoop as a paperweight.

 

[djtimmy77]

Definitely get a petrel for a backup. (Don't be like me and use a two zoops/gekkos for recreational diving.)

All sarcasm aside (based on other recent SB threads), an inexpensive computer that matches well with your primary what I would suggest for a backup. You can get Zoops for <200 new and ~100 used. There are other options in the same price range that may appeal to you more so make sure to look at what is available.

 

[Wookie]

No reason to spend the bucks on a Petrel when Predators are starting to go for $450. That's a completely reasonable price for a backup computer which will become your primary in one dive. You don't have to use the fancy bells and tech diving whistles, set it for 32% and forget it.

 

[Water Boy76]

Regarding your question about needing a second computer the answer is yes. I always run two computer with similiar profiles.
Good luck deciding which computer to buy. Just remember there are many more options available than the one's always pushed on SB.

 

[Damselfish]

We have dove with backup computers for a very long time. When you are doing multiple multilevel dives for days on end, a depth gauge and tables are not much of a backup, practically speaking. Some people will insist they are, but I suspect many of those people have not done that style of diving. A backup computer can save dives, which is good when you have traveled a long way and spent a lot of money to dive. I think for people doing heavy recreational tropical diving, 2 inexpensive computers can be of more utility than one expensive one, if that's the choice. (And it sucks less when a cheap computer floods.)

If you want to get a fancier computer and use the zoop as a backup that works. If you just want to buy another zoop type computer that works too. Similar algorithms are usually more convenient for a backup or for 2 people diving together - though while I've always had Suunto's I don't know that I'd use that argument to tie yourself to Suunto with all the other options out there. (I'd probably go a different route now if we didn't have so many of them kicking around.)

I think if someone has the money and wants to spend it on an expensive toy that's great. But if someone can't or doesn't want to spend a lot on a computer they shouldn't be led into thinking it's necessary. For a long time the mantra on this board was "a computer is unnecessary." Now it's "buy a Petrel." Neither recommendation usually paying any attention to the persons circumstances. It's getting to be right up there with "buy a BP/W."

 

[AdivingBel]

I didn't dive a backup computer until I started liveaboard diving (multi-day, multi-dive, long way from land based resources, etc.). For land based recreational diving with dive shops etc. nearby, I always figured if I had a problem I could rent a computer to fill in. If I was in the midst of NDL pushing dives (single or multi), then I would sit a dive out, if necessary, to get back on track. I've found DCs very reliable and would keep an extra battery with me if I needed it. It worked out well for me in those situations. I do liveaboards now, so I have a backup. YMMV. Safe diving.

 

[Tbar]

You need to consider the actual use of the back-up. If your primary shows you are still within your NDL but your back-up says you need deco what do you do? If you skip the back-ups deco does it lock-out? If so what is the point of the back-up, possibly it is of limited use if you keep diving or you must skip dives until it lets you dive. I use two computers but they are the same model and have the same firmware version. I have found that can the firmware can give quite different NDL. I still find they vary, on my last dive one showed the need for deco the other did not, so I did the 2min at 3m stop then the 3min safety stop.

If you already have a Zoop, that is commented on as very conservative in repetitive dive profiles, you may want another Zoop... If you get a less conservative computer you may want to use the Zoop as the main computer otherwise it may be a locked-up paperweight.

---------- Post added June 11th, 2015 at 08:13 AM ----------

I didn't dive a backup computer until I started liveaboard diving (multi-day, multi-dive, long way from land based resources, etc.). For land based recreational diving with dive shops etc. nearby, I always figured if I had a problem I could rent a computer to fill in. If I was in the midst of NDL pushing dives (single or multi), then I would sit a dive out, if necessary, to get back on track. I've found DCs very reliable and would keep an extra battery with me if I needed it. It worked out well for me in those situations. I do liveaboards now, so I have a backup. YMMV. Safe diving.

Sorry if I have misunderstood the post, but the comments seem dangerous. You cannot just change to another computer when you are in the midst of repetitive dives, that new computer will have no record of the nitrogen level (or O2 if on Nitrox). You need to wait until your body will have released the residual nitrogen, and hence the computer and your body are in a common state.

As far as taking an extra battery, this is good but changing the battery before the trip may avoid the need to change the battery during the trip. I am not sure all computers will keep the current diveplan/residual nitrogen when the battery is changed. I have not tried it with my Puck but given it does not keep the time set I would have concerns that it would not correct nitrogen level.

 

[rprice54]

Thanks for the replies.

I went on a trip with my brother who has an oceanic and while he usually had a few more minutes of bottom time, we both usually ran out of air before time, except when we didn't get good surface intervals- that was on us. It wasn't this dramatic difference. I'm happy to dive conservatively. I can adjust the Suunto 'up' a bit or the oceanic 'down'. I dove with a guy who figured out if he put his 'conservative' Suunto at 23% oxygen vs regular 'air' on his liberal computer he got very similar bottom times. I'm sure some of you just had a seizure. I'm not sure I need to squeeze that blood out of that rock myself.

All that to say I don't mind sticking to the more conservative computer. i personally leave myself a cushion and don't push the limits. I do this for fun.

Maybe I spend a little more on the D4 then. Maybe I give the kid the zoop and I just dive with whatever I want and save the backup for another day. I like the oceanic 'BUD' idea but seems like a high price when I could by another full blown computer for the same price.

Thanks again.

 

[AdivingBel]

Sorry if I have misunderstood the post, but the comments seem dangerous. You cannot just change to another computer when you are in the midst of repetitive dives, that new computer will have no record of the nitrogen level (or O2 if on Nitrox). You need to wait until your body will have released the residual nitrogen, and hence the computer and your body are in a common state.

I belive I said if I was doing repetitive dives or dives that pushed NDLs that I would sit out the necesary dives to clear my system. Sorry if I didn't make that clear. If I'm doing shallow reef dives well within NDLs (based on tables) , I wouldn't have any issues continuing my diving as I have dived on tables & bottom timer before I owned a DC. It's great to have DCs but there was diving long before they existed.

As for changing batteries before every trip...that would be a lot of batteries as I dive travel several times a year. I prefer to change them more or less on an annual basis or sooner based on the amount of usage.