Backup Computer?

[BoltSnap]

Are you guys implying that the folks who do use computers are brain dead or doing something wrong?

 

[Bubbletrubble]

I've opted to dive with a back-up bottom timer/depth guage. In the extremely unlikely event that my computer dies while on a dive trip, I'll simply dive tables the rest of the trip if I can't rent/borrow another computer. Don't see the need to lay out the money for an additional computer when I can fall back on my brain.

If a diver is using RJP's method of using a backup bottom timer/depth gauge, it's important to be "backing out" one's nitrogen-loading status at the end of each dive and recording it somewhere. This can easily be done at the conclusion of a dive by looking at the NDLs for a given depth in dive-planning mode. Simply match up those numbers with the table numbers to determine pressure group.

FWIW, a used non-integrated dive computer can often be purchased for the same price as a new bottom timer and depth gauge. I've never spent more than $125 for a used, nitrox-capable dive computer. Good deals can be had if one is patient. Check Ebay or Craigslist ads.

There should be no problem diving a backup computer with a different algorithm than the primary computer...provided that the dive is conducted in a manner that doesn't "violate" the more conservative computer. (By "violate," I mean surfacing without fulfilling a computer-specified deco obligation.) There can be substantial differences in the NDLs displayed by computers utilizing different algorithms. It's a useful exercise to borrow a friend's computer for a dive just to appreciate such differences.

For the recreational dives that I do locally, my buddy's dive computer is my backup timer and depth gauge. If my computer dies, the dive is called and we ascend together. In this case, I would simply match my depth to my buddy's depth. My buddy would be responsible for timing any stops during the ascent and guiding our ascent rate. It wouldn't be a huge loss to refrain from diving until I can be certain that I've off-gassed sufficiently.

For liveaboard dive vacations or any trip involving multi-day, repetitive diving, I'll carry a second computer so that I don't have to bother with writing down my nitrogen-loading status at the end of each dive. I'm on vacation, after all.

I realize that dive computers are very common nowadays. I also understand that certain instructional agencies teach classes in which tables are not even discussed. So long as recreational divers have a handle on the NDLs given for common depths (e.g., 60 min. at 50 fsw, 50 min. at 60 fsw, etc.) and can appreciate that nitrogen-loading status is a function of time and depth, I don't see a problem with this.

 

[diver 85]

Personally I wouldn't worry about getting a 2nd one, now, SPG?--->Yes.......What part of Louisiana are you in??.....I'm in SW, close to Lake Charles...

 

[knowone]

Will you be purchasing a computer that calculates remaining looking time
which could only be fifty percent of bottom time monitoring all that stuff.

 

[Teamcasa]

I've opted to dive with a back-up bottom timer/depth guage. In the extremely unlikely event that my computer dies while on a dive trip, I'll simply dive tables the rest of the trip if I can't rent/borrow another computer. Don't see the need to lay out the money for an additional computer when I can fall back on my brain.

Ditto.
Here is my backup

 

[vinegarbiscuit]

I see the logic in using a back-up computer with the same algorithm. That said, I've dived with a Dive Rite (Buhlman algorithm) with a Suunto (RGBM) as back-up, and it was no big deal. (I was 'learning' how to use the Dive Rite, but wanted the familiarity of my regular computer, so I wore both.) I always ensured the most conservative computer was clear and happy - in this case, the Suunto - and experienced no problems whatsoever.

 

[GrumpyOldGuy]

Ditto.
Here is my backup

Seems more like 1/2 a backup....

 

[Teamcasa]

Seems more like 1/2 a backup....

How's that? It tracks the 100 most recent dives. Surface Interval time, Max depth, dive duration and water temp. With this info I can switch to tables easy peasy.

 

[BoltSnap]

How's that? It tracks the 100 most recent dives. Surface Interval time, Max depth, dive duration and water temp. With this info I can switch to tables easy peasy.

Probably with the same amount of money, you could have gotten a real dive computer.

 

[GrumpyOldGuy]

How's that? It tracks the 100 most recent dives. Surface Interval time, Max depth, dive duration and water temp. With this info I can switch to tables easy peasy.

Sorry, I thought it was a standard divers watch. My bad.