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NewDaScuba13
07-12-2007, 00:35
Is it an economical choice to have more than one computer? I've heard some people say that they like to have a back-up computer, and also I've heard that you can get one and be set for the rest of your life.

CompuDude
07-12-2007, 01:43
It's not an economical choice to take up scuba diving.

Two is one and one is none, as my SEAL buddies say...

(the second comp does not necessarily have to be as high end as your primary computer, but it is helpful for it to be the same brand so they measure your time limits the same way... meaning, don't mix Suunto and Oceanic, etc!)

woody
07-12-2007, 03:39
I like to have 2 computers along with me for a dive trip that I am on. If it is ever gonna fail it will be at the start of that dream trip you save your whole life for. Does that mean you have to run out and get a second computer right now? Not necessarily so. As you progress in your diving career you will undoubtedly see a new computer that has some new feature that you will want (like the BIG numbers that joe needs at his age!). When you want that new computer get it and move your old one to a backup. Just remember to dive with both computers and follow the most conservative one for your ascents& stops. If you violate required stop or something else on your backup it will be as useful as your broken one is.
<DIV></DIV>Woody.

Sawatdee
07-12-2007, 08:38
I use Suunto Vyper for recreational dives. When I do decodives, I use the Vyper in gauge mode as a bottom timer.
<DIV></DIV>
<DIV>I recently bought an Aeris XR-1 as a back up bottom timer. Cheaper than an Uwatec bottom timer and double as an air computer for mygirlfriend when she finish her OW training. </DIV>

cummings66
07-12-2007, 12:20
I don't see the point in two computers myself. In fact the computer isn't really my primary method of diving and nor should it be yours.
<DIV></DIV>
<DIV>I refer to the computer to see if what I believe to be true is, I don't push it to the limits and it's just to be honest a reality check.</DIV>
<DIV></DIV>
<DIV>If I lost it on a dive most of the time I could go back to the tables and use them so for me 2 computers (which I have and don't dive with) are not needed.</DIV>
<DIV></DIV>
<DIV>Based on the logic of 2 is 1 and 1 is none, maybe nobody should dive a single tank either with twins being the minimum configuration? Say what? You're not going for that, well, apply the same logic to the computer then.</DIV>
<DIV></DIV>
<DIV>Not to pick on CompuDude, he's brought up the perfect point about multiple devices. To be honest, a bottom timer is about the best thing you could use to back up a computer.</DIV>

ertechsg
07-12-2007, 12:58
CompuDude is correct on the economical part. Why buy 2 if it fails just take your buddies he won't mind. No reallyhave a watch for saftey count unless you dive solo you buddie can get you to the20- 15 ft range.Your suppost to stick together RIGHT.

texdiveguy
07-12-2007, 13:05
I dive 2 Dive Rite wrist Nitek Duo's...great computers without all the fluff!

CompuDude
07-12-2007, 13:18
I don't see the point in two computers myself. In fact the computer isn't really my primary method of diving and nor should it be yours.
<div></div>
<div>I refer to the computer to see if what I believe to be true is, I don't push it to the limits and it's just to be honest a reality check.</div>
<div></div>
<div>If I lost it on a dive most of the time I could go back to the tables and use them so for me 2 computers (which I have and don't dive with) are not needed.</div>
<div></div>
<div>Based on the logic of 2 is 1 and 1 is none, maybe nobody should dive a single tank either with twins being the minimum configuration? Say what? You're not going for that, well, apply the same logic to the computer then.</div>
<div></div>
<div>Not to pick on CompuDude, he's brought up the perfect point about multiple devices. To be honest, a bottom timer is about the best thing you could use to back up a computer.</div>
I agree to a point. Obviously you reach the point of diminishing returns (although I know plenty of people that just never dive singles anymore!). But a second computer is not terribly expensive (nor is it required when you're just starting out), it slips into a pocket, not taking up much room... it's just not a bad thing to have. A good BT is a viable option as well, but that brings me to my next point: What kind of diving are you doing? If you're doing easy reef dives within the NDLs, and NOT diving square profiles, cutting tables will work, but not as well as a good computer will. Likewise, what about repetitive dives? I know lots of hard-core DIR divers who are all about doubles and V-Planner when they're diving local wrecks, but when it comes time to travel to Bonaire and you're doing 5 dives per day in 45' water, trying to cut tables gets kind of pointless. Not to mention you really need a better way to track residual nitrogen for extreme repetitive dives like in Bonaire or on a liveaboard, and nothing handles that quite like a computer. The problem is, if your computer dies, you're kinda hosed. And stuck in diving paradise without knowing where to start. If you have a backup computer that you have been diving with, on the other hand, you're good to go.

Training dives in a quarry with a square profile, only doing 1-2 dives per day? A BT (or even a good watch with a depth function) may be all you need. But there are other diving circumstances where different configurations are warranted.

TxHockeyGuy
07-12-2007, 13:55
I like to have 2 computers along with me for a dive trip that I am on. If it is ever gonna fail it will be at the start of that dream trip you save your whole life for. Does that mean you have to run out and get a second computer right now? Not necessarily so. As you progress in your diving career you will undoubtedly see a new computer that has some new feature that you will want (like the BIG numbers that joe needs at his age!). When you want that new computer get it and move your old one to a backup. Just remember to dive with both computers and follow the most conservative one for your ascents&amp; stops. If you violate required stop or something else on your backup it will be as useful as your broken one is.</span>
<div></div>Woody.

Say what! Mr tech dives a computer? I thought you told me just last night that you dive tables.

Seriously I dive 2 computers for exactly the reason above. I don't want to have to switch back to tables and miss 24 hours of diving when I go on a dive vacation (which I will on September 1). That being said I still dive 2 computers even at the local quarry and even in the rescue pool sessions I'm doing now. I do this so I am accustomed to the gear I dive with. About the only things I change up on my gear is the snorkel comes off on non training dives, the compass comes off my wrist in the pool, and I might or might not have a slate with me depending.

texdiveguy
07-12-2007, 14:26
While rec diving I use one dive computer in full mode and back it up with an electronic dive watch.

While doing staged deco dives I use 2 computers in gauge mode with cut tables.

One computer for the beginner is just fine,,,take care of it and practice diving tables once in a while.

Most of all use your brain....DIVE....and have FUN!

frankc420
07-13-2007, 08:12
When using an AI computer and a non-AI computer (backup), the chances of the non-AI going into deco are pretty high, right? Or does the AI computer simply record tissue loading?

CompuDude
07-13-2007, 10:50
When using an AI computer and a non-AI computer (backup), the chances of the non-AI going into deco are pretty high, right? Or does the AI computer simply record tissue loading?

Depends on the AI computer. I know Uwatec's AI computers monitor gas usage and can tweak their algorithms to reduce your BT if you're sucking down air like crazy (they monitor temps as well). Others simply record air usage and use the same tables as non-AI computers, regardless of air usage. I'm not sure if any other manufacturers take air consumption into account with their AI comps.

So at least with Uwatec, yes, you could have less BT with one of their AI comps compared to their non-AI comps. (This is not really a bad thing, of course). If you had to switch to a non-AI backup, however, it would still be running on normal calculations, not accounting for air consumption, which it has no idea about. That's an interesting point I had not considered before.

However, either way, you would be no worse off than using the non-AI computer in the first place, since it will always be the more liberal of the two.

woody
07-13-2007, 13:27
Say what! Mr tech dives a computer? I thought you told me just last night that you dive tables.

<DIV></DIV>
<DIV>Just like texdiveguy,</DIV>
<DIV></DIV>
<DIV>I dive tables for anything Deco. It's hard to dive tables on mulit-level dives on multi-dive days for mulitple days on a dive trip. That's where a good conservative computer, nitrox and a good head on your shoulders comes in.</DIV>
<DIV>Thanks,</DIV>
<DIV>Woody</DIV>

cummings66
07-13-2007, 14:08
It's kind of an unwritten rule, woody has spilled the beans and now everybody knows it.
<DIV></DIV>
<DIV>Computers have their places and then there are places they shouldn't be, IMO. I love my VT3 and so does my buddy who owns that one. But we both use our heads first and computer second.</DIV>
<DIV></DIV>
<DIV>Was it this board I got into a hassle because I said I don't use my computer to judge my ascent rate and I used other means?</DIV>

frankc420
07-14-2007, 11:34
<div>Was it this board I got into a hassle because I said I don't use my computer to judge my ascent rate and I used other means?</div>

What other means do you use?

plot
07-14-2007, 18:38
When I buy a new computer for the new upgraded cool features or something, then I'll keep my old one as a back up.
<DIV></DIV>
<DIV>Outside of that... I don't see a point if you're only doing open water dives, where you can thumb it anytime your computer fails.</DIV>

Zeagle Eagle
12-21-2008, 08:24
Is it an economical choice to have more than one computer? I've heard some people say that they like to have a back-up computer, and also I've heard that you can get one and be set for the rest of your life.

I use two computers and so does my girlfriend as well as both of my kids. Economical? MMMM...depends on how you define that and your circumstances. If it saves the day when your primary comp. quits then it was a good idea. Pretty much every piece of dive equipment I have ever owned has crapped out at on time or another. If you can afford two then do it, if you can't well then its a moot point.

rawalker
12-21-2008, 13:04
When I dive with someone other than my wife I dive with 2 computers.
I grab her VT3 as a backup. We only dive OW non deco but I like the idea of not needing to thumb the dive due to a computer failure.
It isn't as if I've ever had a problem with any computer I've owned. All have worked flawlessly and I expect they will continue to until they don't.

As for AI vs non-AI my computers are all AI. On my Oceanics even if the transmitter fails the computer continues to work without the pressure related functions. This allows me to thumb the dive, change the transmitter battery or replace the transmitter (I do have a spare) and get back in the water imediately if all else allows me to.

Just a few days ago I came upon a sweet deal on a used Atom 1.0 and it is in the mail at this time. Now I will be able to have a backup on all dives.

Splitlip
12-21-2008, 13:54
I have had 3 computer failures. Kept tables and an aqualand watch with depth guage and dive timer as backup along with tables in a pocket.

Now I simply dive 2 computers. An Uwatech Aladin tec and a Scubapro wrist watch computer. I have a third ntrox computer as well that stays in the save a dive kit.

gbrdiver
12-21-2008, 15:51
I have had a Suunto go Er during a surface interval, a Nitek He stop counting down the deco, an Alladin discharge a new new battery in two dives and have seen many other computer issues that have affected divers repetitive dive programs. Personally I use 2 computers of different brands that often give totally different NDL's and deco times and just use the most conservative reading.

Aussie
12-22-2008, 06:46
I dive with two Suunto's. A D9 and a Vytec. I actually bought the Vytec off ebay for a steal. They are both AI which is handy but not essential. Both are set at the same Algorythm. I do get some different readings between the two computers from time to time. Tank pressure difference is only one bar and the depth difference is 10cm.

I feel more comfortable when diving a liveaboard or resort where I am doing alot of different diving, many times a day over a series of days. I have had my own computer fail a couple of times and seen alot of other divers computers fail also.

I also pack an old Aladin Pro. I bought it off a mate for couple of cartons of beer. Its good to have to lend to people when theirs fails or someone forgot to bring theirs.

Regards Mark

RoyN
12-24-2008, 12:46
Just one computer is enough for me. Now I need is a transmitter for my deco bottle.

Travman
01-11-2009, 18:30
I'm a skydiver and we are always taught to have a backup. I jump with an audible altimeter and a visual altimeter so if one fails I have the other, not mention a reserve parachute in case of a main failure and an automatic activation device in case I fail to deploy.
When I started scuba diving it just seemed second nature to me to use 2 computers. So I bought a Mares Airlab as my primary and Mares Nemo as my secondary because they use the same algorithm and I have used both on every dive since.