Rec Diver splurge? Cheapo, Petrel 2, or OSTC Sport

[Tbar]

I run big computers for living. IME if your computer failure is quite common, the most cost-effective solution is to find a different vendor.

If your computer failure is quite common, firstly do environmental and other checks...
Running big computers for living, I expect you use an n+1 model.

 

[Centrals]

I'm curious as to why/when one of your Aladins expired and the other one didn't.

Are you suggesting that if I bought two identical equipment manufactured at the same time and use them together under identical conditions then they should last the same distance?

 

[dmaziuk]

If your computer failure is quite common, firstly do environmental and other checks...
Running big computers for living, I expect you use an n+1 model.

Yes, all obvious suspects eliminated first and all that. But we only run a few in n+1 setups, actually, and more because it looks good on the annual reports: we just have proper hardware properly set up (edit: and rotated off before it gets too old), so the only downtime is maintenance reboots. Plus you have to realize that 100.0000000% uptime between the rack and the switch is 100.0000000% useless when a backhoe bites into the fiber uplink outside.

At some point you just have to let it drop and deal with the fallout. The trick if figuring out where that point is.

 

[dmaziuk]

Are you suggesting that if I bought two identical equipment manufactured at the same time and use them together under identical conditions then they should last the same distance?

Give or take, of course. And depending on what it is, too, but yes: why wouldn't they?

 

[Tbar]

At some point you just have to let it drop and deal with the fallout. The trick if figuring out where that point is.

Agreed, that is why I have two dive computers. Just one the failure of the dive computer will stop diving until 24 hours have elapsed, assuming the computer can be fixed or another is available that has no RNT by dive time. Generally for recreational diving, for other gear (reg, bcd, tank) a failure will abort the dive but if it can be fixed or replaced there is no other restriction to diving. (I do carry spare 1st & 2nd stages, hoses, SPG, batteries and parts kits/tools on most trips. If diving dry I have spare seals.)

If I pay thousands of dollars for travel and a live aboard trip in some exotic location I do not want to miss a single dive - the boat moves on and the opportunity is gone. And with computers the price they are why not have two each. The best average cost I have managed on a live aboard is about $AU100/dive (included flights and trip cost) but I would say most are over $200AU/dive. A recent Galapagos trip the average cost per dive (and I did all 20) was $275AU. Loss of 24 hours is 4 dives missed on these trips. I have paid less than $200AU per computer.

 

[dmaziuk]

Fair enough.

Where/how I dive, dead computer may make me thumb the dive, but most likely I'll finish on my buddy's time. I'll then rent a computer from the op and may up its conservatism factor dep. on how far into the trip I am by then.

Flat battery, OTOH, is a failure mode that is both likely and cheap to fix. I always have a couple of spares with me.

 

[stuartv]

I'm with @Tbar. Even if it's just a 2-tank dive down in NC. If my computer dies during dive 1, renting/borrowing a "clean" computer for dive 2 would require me to be so conservative on my second dive that, while I would still probably do the 2nd dive, it would likely end up so short that, well, I just choose to avoid the problem - by diving with 2 computers. I would rather have a cheap 2nd computer in gauge mode than nothing at all. At least with that I would get out after the 1st diving really KNOWING what my max depth and dive time were. Maybe even able to download the first dive's profile to properly plan a 2nd dive on a tablet or laptop.

I have dived there enough to have a pretty good idea what my first and second dive profiles should be. But, I still wouldn't dive on my buddy's computer. It just wouldn't be worth it, to me. In the grand scheme of scuba spending, having a second computer for backup is really a drop in the bucket.

 

[dmaziuk]

2nd computer in a gauge mode will want you to wait 24 hours before its (no-)deco calculations become valid. If you want to adjust for residual loading you up its conservatism, making it no different from 'renting/borrowing a "clean" computer for dive 2 would require me to be so conservative on my second dive that' it's just not worth getting wet in the first place.

Are you sure you don't want to run your perdix and tx-1 in dive mode both? (They'll both read the same tank transmitter(s) too, right?)

 

[stuartv]

2nd computer in a gauge mode will want you to wait 24 hours before its (no-)deco calculations become valid. If you want to adjust for residual loading you up its conservatism, making it no different from 'renting/borrowing a "clean" computer for dive 2 would require me to be so conservative on my second dive that' it's just not worth getting wet in the first place.

Are you sure you don't want to run your perdix and tx-1 in dive mode both? (They'll both read the same tank transmitter(s) too, right?)

I understand. What I meant was, that if I only had 1 computer and I didn't want to shell out for another "expensive" computer just to have as a backup, then I would rather have a cheap computer in gauge mode than no backup computer at all. If I were only diving Nitrox, then I would not use the cheap backup computer in gauge mode (I would use it in normal Dive mode) and would just use it as is for dive 2.

Upping the conservatism on a clean computer is not the same as using dive data from a bottom timer (i.e. computer in gauge mode) to plan a second dive. Higher conservatism on a clean computer is still going to assume all your compartments are "clean" (or the equivalent for whatever model it uses), which is simply not the case. And that could still result in you getting a much higher final loading than you would want after your 2nd dive. Maybe it's "close enough" for ordinary single tank recreational diving. But, how do you know?

I do run my two computers in dive mode. And, yes, my TX-1, Atom, and Perdix all read the same transmitters. But, I actually use my H3 and Perdix and the TX-1 is being sold to a buddy. The Atom may stay, as a backup to the backup - and to use on recreational dives, instead of the bulkier Perdix. But, if the H3 or Perdix crapped out and I was doing a tech dive, as I said earlier, I would use the Atom in Gauge mode. If the primary computer crapped out, I would use the data from the Atom to plan my subsequent dives, so that I did not have to sit out for 24 hours and so that I did not have to totally fudge things by diving a clean computer with bumped up Conservatism (which I wouldn't have any way to know exactly what it was doing).

 

[dmaziuk]

Upping the conservatism on a clean computer is not the same as using dive data from a bottom timer (i.e. computer in gauge mode) to plan a second dive. Higher conservatism on a clean computer is still going to assume all your compartments are "clean" (or the equivalent for whatever model it uses), which is simply not the case. And that could still result in you getting a much higher final loading than you would want after your 2nd dive. Maybe it's "close enough" for ordinary single tank recreational diving. But, how do you know?

I don't know, I decide. I am the decider.