Backup computer questions

[RyanT]

Shearwater primary and puck computer in gauge mode as my bottom timer. Dive profile is pre-planned on a slate so that I can revert to my written plan and back up bottom timer.

 

[OMANDIVER]

Shearwater primary and puck computer in gauge mode as my bottom timer. Dive profile is pre-planned on a slate so that I can revert to my written plan and back up bottom timer.

+1 but with a Uwatec. I plan on a conservative profile but set the SW to a mid to aggressive profile so that in an emergency I know what the min deco obligation I have if I need to get to the surface quickly in an emergency eg unconscious buddy, short of gas etc

 

[lerpy]

I am also a Shearwater primary guy with a Uwatec BT for my backup. I write out my profile, as well as a profile for +5. I have also made and laminated tables for dive depth of 110-150 and times from 15-40 minutes with all stops for reference if needed.

 

[_Ralph]

Bottom Timer on the wrist, buddy has the backup (and vice-versa). Usually there might be a GF computer tucked away in a pocket if we really want to get out of the water sooner.... (usually on a second or third dive)

_R

 

[packrat12]

...I agree that the same computer with the same firmware is a single point of failure...

I will play devil's advocate here. Two of the same or different it does not matter. Which one failed? Unless it is obvious I doubt I would be sure, hence the idea of triple redundancy with voting when it counts (e.g. CCR O2 cells).

If you are that concerned, use two different firmware versions. Companies like Shearwater are always updating and improving their software so it is not hard to maintain, although the core code is common between them. I also would trust a good company like Shearwater to be very careful with the core code.

Also a highly used company, again Shearwater, will have numerous dives on each version before a normal tech/rec diver would use it. I would suspect any specific issues would already be known. Again a reputable company like Shearwater will also promulgate it out and not 'hide' it in the background, as they have done in the past.

Lastly, I cannot think a major software failure with Shearwater where their computers have left a diver in a lurch. Even if it did happen, I doubt using two computers would have the same failure. No matter where you have them, they have different conditional input parameters, e.g. depth and time. Mine are separated by 1' by placement as an example.

 

[Tug]

Back when I was diving OC I had my computer (Shearwater) and then I used a backup bottom timer. Now diving a rebreather, I have my primary (shearwater again) and a second shearwater since I had it before I switched to a rebreather.

 

[OMANDIVER]

You can always tell when there's a pilot in the room....

 

[RainPilot]

Was it something I said?

 

[OMANDIVER]

Was it something I said?

Not yet!

 

[RainPilot]

Better?


FWIW I use a Perdix for primary on OC and a Nitek Q as backup. I have the Q as a spare cell reader for CC but much prefer the Perdix. I run the Nitek on a slightly more aggressive GF as a get out fast method if needed.