computers and redundancy

[mongoose]

I am a newbie, first off, and try to be as risk-averse as possible. I have an atmos AI, and was thinking of getting an atmos I as a backup. The Atmos I is non-nitrox.

I figure:
-- Both units will give me my bottom time.
-- Both units will give me my current/max depth.
-- If either unit fails, I would go to the surface.
-- If my AI fails, I would know it because I check my computer frequently(at least 1-2 min). I can then resurface with the Atmos I.
-- If the AI fails, I have lost my SPG, but if I am following the rule of thirds, and have planned my gas, I should still be able to surface.
-- I also carry a spare air.
-- If I am diving nitrox the wrist computer will be even more conservative, since it thinks I am on air.

The only gripe is I can't get average depth with either unit. I have to d/l the dive into Aeris's software & run the dive data through a &^$% spreadsheet to get avg depth(and then my SAC rate).

Am I making sense or a big mistake here?

I have seen analog dive watches with LCD bottom timers built in but they are *way* too expensive. I think getting the Atmos I is the best fit, even though I don't get avg depth.

Any recommendations?

 

[J75]

Wear primary computer on my wrist, backup on my console. Also ware a watch and carry tables in my pocket for emergency backup.

 

[WarmWaterDiver]

Since I plan to dive at Bikini Atoll within the next couple of years, I was very interested that the dive operation there now allows for use of 2 multi-gas capable technical diving computers as an alternative to one such dive computer and PC generated tables / plan with a bottom timer. So, I picked up a TUSA IQ-700 recently to complement my veteran Dive Rite NiTek 3. We'll probably hit Truk Lagoon next year, then Bikini the year after that. This is something we've been working towards the past few years.

http://www.bikiniatoll.com/fabioletter.html

The TUSA IQ-700 and Apeks Quantum are functionally identical to the DR NiTek Duo - the new Cressi Archimede 2 would be the same for functionality as well. The Apeks Pulse is functionally identical to the DR NiTek Plus.

All our technical (planned decompression) dives done thus far have been to follow a PC generated profile with a bottom timer, with our NiTek 3's as backup.

 

[TostitoBandito]

I was just wondering what redundancies you use for your computer (especially on a tech dive), and whether the backup equipment is with you on the dive or you keep it in the car / boat (keeping it at home doesn't count). If you take it on the dive, where do you wear it?

If your computer is AI, do you have a backup gauge?
A backup computer?
Charts?
A timer?
Depth gauge?
Thermometer? Calendar? (just kidding)

For me, I'm thinking of putting a depth gauge in a pocket, but wondering whether that's being over-cautious.

I have a hoseless AI computer (Aeris Atmos Elite) and I still dive with a full SPG/Depth/Compass console. I can't think of a good reason why you wouldn't want backups.

 

[TostitoBandito]

-- I also carry a spare air.

Yikes, why?

 

[Doc Intrepid]

I don't own a computer. I use a Uwatec BT on my right wrist. My back-up is on my buddy's right wrist. The diveplan is memorized, but is also laminated in my wetnotes along with some bail-outs. I use V-Planner. Compass on left wrist. Occasionally I'll also wear a wrist slate on my left arm with some compass azimuths or other notes on it.

 

[SteveFass]

What an interesting thread (if I do say so myself). Until this thread, I had thought that a computer today was considered a necessary piece of equipment. But now I know some people do not use any computers, and others use three. Plus people dive with all different combinations of bottom timers, watches, or just a good plan written on their fin. Lots to consider.

I'd like to hear from more people on this.

 

[Uncle Pug]

I use my Suunto Stinger in gauge mode for a bottom timer/depth gauge. It would be cheaper to use my Uwatec BT/DG but I can download the Stinger later IF I remember to take it with me on the dive.

Yesterday I was already in the water when I realized I'd forgotten it... again. Oh well... I can always make the entry in the log:

First dive 105' max for 60 minutes.
For SI ate a Breadbowl~0~Chowdah.
Second dive 105' max for 70 minutes.


My SPG told me all I really needed to know for these dives since it combined both depth and time into one reading.

It's kinda like needing to be home in time for dinner:

A digital watch will give you a precise read out but you can just glance at an analog watch and get a good feel for when it is time to get going. In fact an analog watch without numbers and only an hour hand can do the job.

However if you don't plan to not be late for dinner even the best digital watch won't help.

So... to answer your question about what backup I use. The back up to my brain is my SPG. The backup to my SPG is the BT/DG. The back up to that is my buddy's BT/DG.

 

[UnixSage]

I have seen analog dive watches with LCD bottom timers built in but they are *way* too expensive.

I stumbled accross a simple bottom timer a Timex Helix DM.. It has a dive mode that will tell your maximum depth and total time below 5 ft.. so it does NOT credit you when you come back up. I paid $40 for it. The only down side is that I understand that cold water (sub 38F) bothers it.

Thanks
John

 

[mello-yellow]

I just bought a used computer (air-integrated) -- after more than 90 dives without one. I am not terribly confident about its reliability, so I wear a watch and keep an SPG clipped to my BC; thought about keeping it in a pocket, decided it is better where I can easily see it. I have a tank pressure gauge, but keep it in the car -- it introduces another point of failure, however unlikely, and if my computer fails, I will just head for the surface. If it happens on the first dive of the day, I'll just attach the pressure gauge for the second dive.

Since buying this computer, I did not yet do any dives which require a pony bottle (60'+, as far as I am concerned). When I do, I think I will attach pressure gauge to my main tank, and the computer to the pony -- because I trust the former more. Oh, and I carry dive tables in BC pockets when diving deeper than 60'.

I do not do tech yet.