Necessity of a back up computer/watch for NDL diving

[dmaziuk]

So... you have all of the formulae in ZHL-16 between your ears? That's rather impressive. Kudos.

If I were pushing the limits on 4 dives/day for 4 days straight and my computer died, what I have between my ears would tell me to not go on a dive that could put me close to the limits. You know, sit one out, enjoy the sun, have a beer, run ZH-L16 formulae on my laptop.

 

[BlueTrin]

So... you have all of the formulae in ZHL-16 between your ears? That's rather impressive. Kudos.

He has a pressure gauge integrated ... integrated between the ears

 

[caruso]

If I were pushing the limits on 4 dives/day for 4 days straight and my computer died, what I have between my ears would tell me to not go on a dive that could put me close to the limits. You know, sit one out, enjoy the sun, have a beer, run ZH-L16 formulae on my laptop.

See that's the issue entirely. Your brain cannot calculate and process the massive amounts of data nearly as precisely as a dive computer. The best you can do, using tables is to make an educated guess which will still include a fair amount of rounding off because let's face it, no dive is a perfectly square profile.

If I'm on a dive trip that I paid a lot of money to go on, and went through the trouble of lugging my dive gear sometimes thousands of miles away, I'm going to dive. As much as possible. Others might be ok to skip an intended dive here or there and sit on a beach chair drinking beer and playing car racing games on a computer- but I'm not one of them. It would seriously bum me out if I had to skip a dive because I "wasn't sure if I could do it" because I didn't spend the $75 for a backup computer which can answer the question for me, and most likely say "yes you can dive". Thank you Mr. Backup computer, you were money well spent.

 

[scubadada]

It's personal, I don't want to skip part of one dive, let alone interfere with a series, and I don't have to.

 

[Steelyeyes]

I thought it was broken because I didn't see a needle.

Oh wow. I forgot about those. I'd have a tough time seeing the bubble line now days but that's what I started with. We used the J valve tanks. It was a big step up when my dive buddy bought an SPG.

I embrace technology and always have. I just missed the slide rule days when I started my training in the nuclear power program in the Navy, those newfangled electronic calculators were just fine with me. I operated old school power plants and had to synchronize generators with a scope. Now it's automated, and it works better than an average operator did.

I dove tables and gauges. Now computers do far more calculations on a dive than I ever did and keep track of multi level dives better than I could. They safely (in 300 dives or so anyway) have done their job and the benefit as far as I can see it is more bottom time. Having a second one when you're far from a dive shop is just part of a save a dive kit as far as I'm concerned. Everyone's milage surely varies. Dive and let dive.

 

[MargaritaMike]

I just missed the slide rule days when I started my training in the nuclear power program in the Navy, those newfangled electronic calculators were just fine with me.

This is interesting. I just rebuilt my slide rule day on Monday. Still works like a champ! With or without batteries.

Having a second one when you're far from a dive shop is just part of a save a dive kit as far as I'm concerned. Everyone's milage surely varies.

I have only needed to rent from a dive shop on one occasion. The computer I got worked fine in the shop and on the boat. In the water it was less than worthless. Fortunately, I had a watch, depth gauge, and SPG. I did the dive and then basically advised the shop to put their computer in a location where computers are seldom found. Since then I have ALWAYS had at least 2 computers. As I said earlier in this thread, redundancy is part of a Save-A-Dive TRIP kit.

Cheers -

 

[WarrenZ]

Just remember a dive computer has no idea what is actually happening inside the wearers body, a backup computer only knows about the dives it has been on. If it is in your bag for half the trip then you have to do the 12 hour wait the same as if you were switching to tables.

 

[broncobowsher]

So the title of the post askes about the necessity of a back up computer,
But the survey asks if you wear one.
I find this flawed.

While I don't need a back up computer for NDL diving, I still have one and use it.
Not that the second was bought as a backup, but rather I got a modern computer and the old one still works. It could have value. Actually more work to remove than to leave in place as well.

 

[dmaziuk]

If I'm on a dive trip that I paid a lot of money to go on, and went through the trouble of lugging my dive gear sometimes thousands of miles away, I'm going to dive. As much as possible.

I would take 2 computers on such trip myself. (Edit) What does not follow is that I need two computers because I can't accurately figure out my accumulated gas loading. The argument is actually that I need two computers because someone out there dives like that. Sure, and if my auntie had a schlong...

 

[Clayton122]

Hi Clayton,

With my Oceanics, there is default switch that can be turned off so the computer does not default to 21%. The 21% default is turned off on all of ours.

dive on,
mm

Thanks! Good to know. Im actually going to sell my Oceanics as I just bought a Shearwater Perdix AI.