Do I need a backup computer?

[ClayJar]

won't say what comp i use, but i had a serious violation on my 3rd dive with it (current and sea state contributed to this) o got locked out for 24 hours, but for some unknown reason i had brought my wifes regs and guages so i got to complete the other dive for the day.

This will likely sound a bit presumptuous, but I'm genuinely curious: Why dive with the computer at all if you're going to ignore it?

The problem with the Suunto transmitter is that the code-changing procedure is turning the pressure below 15 bars and quickly (within 20 secs) turn it up again.

Somehow, I can just see an OW student with their valve mostly closed resetting their code as the pressure bounces each breath.

 

[Cheekymonkey]

I use a vtpro for all of my rec diving, and have only lost sync a couple times in a couple hundred dives with it, and it has synced back up within about 4 seconds each time.

 

[MartianBeerPig]

I just use a watch for back up. Oh and a ribbon tied to the string of my safety sausage. Logic is that if my dive comp goes, it's time to abort the dive. I use the watch for the safety stop. If the watch goes too, I let loose with the sausage and measure my depth with the ribbon and count.

 

[NiNbubble]

Sigh...I have resigned to buying a backup....and attaching it to the other HP port on my first stage. Will probably get another Suunto ...perhaps a Cobra. I am just wondering if it is overkill? kinda makes the D9 wireless seem like a accessory/fashion statement.

A cobra would be serious overkill. The only thing failing is AI and not knowing your remaining cilinder pressure is a reason to abort the dive. A spare SPG of around $50 is actually all you need, the D9 will still function without transmission. If your D9 fails completely, you can just rely on your buddy's depth gauge/compass to end the dive safely.

I'd say spend the $400 or something else

 

[NiNbubble]

Maybe another reason not to go for a cobra is that it's good practice to abide by the most conservative computer you're using. If you use the RGB50 option in the D9, the cobra will get you out of the water much more quickly...could as well give the D9 to me

 

[Colliam7]

"I have an expensive wireless AI primary computer. BUT, should it fail, I'm ok for gas readings because I have an analog SPG at all times. … No need for another spendy AI computer, just a small, inexpensive backup from the same company.

I agree. Personally, I prefer having an analog SPG as my primary pressure information source. I dive a Vytec and every once in a while have had some syncing problems (4 times in 3 years). I replaced the battery on the transmitter and haven’t had problems since, but that is possibly serendipity and they may occur again. In any event, the problems were never dive-ending events, because I had my analog SPG / depth gauge. Plus, the computer still worked, it just didn’t provide air info.

When I started tec, I added a non-AI computer as a back-up (Nitek He). And, when diving doubles, I don’t use the transmitter anyway. For rec diving, I find that the AI feature is convenient – it is on my wrist, easy to check quickly, etc., - but definitely not essential.

Sigh...I have resigned to buying a backup....and attaching it to the other HP port on my first stage. Will probably get another Suunto ...perhaps a Cobra. I am just wondering if it is overkill? kinda makes the D9 wireless seem like a accessory/fashion statement.

Interesting outcome. Individually, I would say it is overkill, as a number of others have suggested. But, you are the one who needs to be comfortable with the choice. For recreational diving, it seems a tad expensive to have a back-up, air-integrated computer instead of an analog SPG.

 

[Eskasi]

Well, its only overkill......I'll see what I can get in Malta. The prices there for gear seem pretty good compared to the rest of Europe and the UK.

Thanks for the advice. I just hate that I chose to go wireless and now have a darned hose for my backup??! Unless I call the dive if there is a failure, surface safely, attach the SPG I have in my gear bag and continue? Is that the recommendation?

 

[diver 85]

Honestly, a computer(much less a backup one) is not necessary........There are tables for diving, just use the old brain & you'll make it.......But the DIR's won't believe that, just ask them........Remember, though, that's J'sDT(Joe's Diving Theory), not many read that book.....lol........A computer is just another trick to put in your bag, & also, @ what point do you quite carrying backups for backups.......I'm thinking @ 16 redundant tanks & regulators you'll be 100% safe(assuming your buddy is equally equiped,lol).......

 

[Eskasi]

lol...talk about being an Octopus (instead of having one)

 

[NiNbubble]

Honestly, a computer(much less a backup one) is not necessary........

I agree, a computer is for convenience. Adding a backup computer induces risks because you could get the habit of ignoring the most conservative one and switching the one you actually use between dives.

I always hook an spg to the second hp valve and tuck it safely away in my bcd just in case. It's no use keeping it in your gear bag and switching between dives, because this would be the same as reconnecting your D9 to your transmitter. Always take both.