Double Dive Computer Redundancy (on little T-Rex Arms)

[Bubblesong]

Not Just the double dive computers, but all the other arm mounted devices, (see photo), where does all this stuff go?
Other Questions:
1)Do you dive two dive computers?
2)Do you carry backup dive watch, compass, depth gauge, tank air gauge, or just plan to abort the dive in case of DC failure?
3) If two DC are used; are both identical, both same brand, each different brands, each different algorithms?
3)If using a transmitter, do both computers work with AI, or will one be independent of that potential failure point?
4) If different algorithms, do you have to dive the most conservative DC at all times, or dive conservatively on your liberal algorithm DC?
5)Are they both on your arm, or can you leave one in a pocket and still have it read ok?
6) How much does the console become critical, is it never possible to stream line that one hose off the reg?
7) Who has room for an arm-mounted dive slate?

 

[doctormike]

1)Do you dive two dive computers?

Yes

2)Do you carry backup dive watch, compass, depth gauge, tank air gauge, or just plan to abort the dive in case of DC failure?

Not sure I understand this question - in case of DC failure, I would rely on my backup DC to provide decompression information. If this was a technical dive, I would also have a slate with an ascent profile. If not a technical dive, the backup computer would let you continue diving in case of a DC failure, otherwise just ascend and thumb the dive if you lose your only DC. In this scenario, both computers have to have been with you for all of your dives that day.

3) If two DC are used; are both identical, both same brand, each different brands, each different algorithms?

I use same brand, same algorithm

3)If using a transmitter, do both computers work with AI, or will one be independent of that potential failure point?

If you are using a DC with AI in place of an SPG, and that DC fails, then you would only be able to continue the dive if you had AI on your backup DC. If you don't have AI on your backup DC, and you don't have an SPG, you would need to thumb the dive. Personally, I just use an SPG

4) If different algorithms, do you have to dive the most conservative DC at all times, or dive conservatively on your liberal algorithm DC?

Lots of threads on this, it's rarely as simple as one DC being more or less conservative. Rather, they generate different ascent profiles in different situations. But I guess if you were being aggressive by diving your liberal DC as your primary DC and it fails, and you have to switch to a more conservative DC, then you should follow the NDLs of that DC, or do the deco it tells you to do if you have already put that one into deco.

5)Are they both on your arm, or can you leave one in a pocket and still have it read ok?

I think that it's fine to have your backup DC clipped off somewhere. You don't need to watch it constantly, especially if you have limited arm real estate. I'm assuming that you are doing a recreational dive, so if your DC fails, look at your backup, see what your NDL is, and just check it occasionally, especially if you are changing depth. I suppose you could take off your dead primary DC, clip that off, and put the backup on your wrist if you wanted..

6) How much does the console become critical, is it never possible to stream line that one hose off the reg?

I don't understand this question.

7) Who has room for an arm-mounted dive slate?

Me

 

[ATJ]

View attachment 447617
Not Just the double dive computers, but all the other arm mounted devices, (see photo), where does all this stuff go?
Other Questions:

1)Do you dive two dive computers?
Yes. And a dive watch but they are all mounted on my computer rig for better viewing - almost a heads up display.

2)Do you carry backup dive watch, compass, depth gauge, tank air gauge, or just plan to abort the dive in case of DC failure?
I carry a spare of all.

3) If two DC are used; are both identical, both same brand, each different brands, each different algorithms?
Different brand, different algorithms, go by the most conservative one,

3)If using a transmitter, do both computers work with AI, or will one be independent of that potential failure point?
Both computers work with the transmitters.

4) If different algorithms, do you have to dive the most conservative DC at all times, or dive conservatively on your liberal algorithm DC?
Most conservative.

5)Are they both on your arm, or can you leave one in a pocket and still have it read ok?
Camera rig. Far more readable that on the arm.

6) How much does the console become critical, is it never possible to stream line that one hose off the reg?
SPG on regs only for backup.

7) Who has room for an arm-mounted dive slate?
I have nothing on my arms.

 

[lowviz]

1)Do you dive two dive computers?

Only on what I call my bigger dives. Almost always, no.

2)Do you carry backup dive watch, compass, depth gauge, tank air gauge, or just plan to abort the dive in case of DC failure?

If anything goes paws-up, I'm out.

3) If two DC are used; are both identical, both same brand, each different brands, each different algorithms?

Different.

4) If different algorithms, do you have to dive the most conservative DC at all times, or dive conservatively on your liberal algorithm DC?

I dive a conservative DC but don't mind doing the hang time for a few minutes of deco.

5)Are they both on your arm, or can you leave one in a pocket and still have it read ok?

In pocket if it comes along.

6) How much does the console become critical, is it never possible to stream line that one hose off the reg?

I can't stand consoles, compass is IN my dive computer.

7) Who has room for an arm-mounted dive slate?

See pic. Line cutter, slate, PDC, compass. Only takes up one parking spot on your arm. Not my clever idea, I bought it from Cave Adventurers.

 

[BoltSnap]

1)Do you dive two dive computers?

No, I use three DC

2)Do you carry backup dive watch, compass, depth gauge, tank air gauge, or just plan to abort the dive in case of DC failure?

No dive watch.

Use a compass on a slate and retractor.

I use an AI console.

3) If two DC are used; are both identical, both same brand, each different brands, each different algorithms?

Different

3)If using a transmitter, do both computers work with AI, or will one be independent of that potential failure point?

All AI. One "hoseless" with transmitter, one on hose and one AI but no transmitter.

4) If different algorithms, do you have to dive the most conservative DC at all times, or dive conservatively on your liberal algorithm DC?

Go by most conservative usually.

5)Are they both on your arm, or can you leave one in a pocket and still have it read ok?

Two on arm and one on hose console

6) How much does the console become critical, is it never possible to stream line that one hose off the reg?

??

7) Who has room for an arm-mounted dive slate?

I do.

 

[KeithG]

3 DCs. All the same brand and algorithm. 1 on my arm, the others in my bcd pocket.

I used to leave my extra DC in my dive bag but I had a computer fail on me. It took about 5 dives before the substituted spare caught up to my primary.

 

[Lorenzoid]

1)Do you dive two dive computers?

For expensive dive vacations, where a DC failure might mean sitting out the rest of the day's dives, I do carry a backup. For local diving, nah. I don't do tech diving, but I'm sure I would carry two if I did.

2)Do you carry backup dive watch, compass, depth gauge, tank air gauge, or just plan to abort the dive in case of DC failure?

Unless I were to carry a backup DC (which is the previous question), I would follow what I suppose is the generally accepted procedure for rec diving and abort the dive if I had a DC failure. I do not carry a backup compass, depth gauge, or tank air gauge (SPG). Compass failure is not cause for aborting a dive (and do compasses ever fail?). Depth gauge is built into the DC, so same answer as above for DC failure. I suppose if I had an air-integrated computer, I would abort the dive if I could no longer read my tank pressure. I use an old fashioned mechanical SPG, and I suppose I would abort the dive or at least wind it up sooner if it suddenly gave me a clearly incorrect reading.

3) If two DC are used; are both identical, both same brand, each different brands, each different algorithms?

Ideally, yes. But like many people, my old DC serves as my backup, and it's a different brand and algorithm.

4) If different algorithms, do you have to dive the most conservative DC at all times, or dive conservatively on your liberal algorithm DC?

I follow the DC that I designate as my primary, which is in many circumstances more liberal than the DC I carry as a backup.

5)Are they both on your arm, or can you leave one in a pocket and still have it read ok?

If it fits in a pocket and I have a pocket, I would gladly leave the backup DC in a pocket. Since I abort a dive if a DC fails, I would need it on the next dive.

6) How much does the console become critical, is it never possible to stream line that one hose off the reg?

I don't have a a console. DC is on my wrist, and SPG is clipped to a D-ring on my hip.

7) Who has room for an arm-mounted dive slate?

I take one sometimes, even on recreational dives. It's annoying, and nine dives out of ten I don't use it. But when there's something I just can't seem to communicate with hand signals, I'm glad I had it. It all depends on the dive. If I'm on a tropical reef enjoying my vacation, I'm not going to wear a slate.

 

[Bubblesong]

@ATJ if your computer is on your camera rig, it seems a little dicey because I hear people lose cameras more frequently, although the money cost of losing a DC doesn’t compare to a camera rig, it still has your dive history.

@lowviz that photo is helpful because it never occurred to me to rig a DIY set up with a flip dive slate, I am going to have a look at those now.

And 3DC? Dang that’s determined not to lose your dive records!

 

[runsongas]

i mount the compass on the back of my hand. i stack both computers the same distance up the forearm instead of having one further up and one lower down. this saves some space for the slate.

 

[Bert van den Berg]

Use two dive computers only when diving solo. Do not use redundant compass or pressure gauge, have pony bottle for redundant air source. Two SMB's and one cutting tool. Two means of signalling (whistle and torch/flashlight).