If you folks use a wrist computer. Do you use a transmitter or a spg? I hear all the time about using a wrist but what do you use to check pressure? I think it would a pain to have a wrist and still use a hose spg to check pressure. I guess, I feel its too much playing around. I cannot afford the transmitter kind, so I am thinking about a AI computer console. Thankyou for any info.
If you folks use a wrist computer. Do you use a transmitter or a spg?
- Thread starter mason417
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I have a VT3, I'll be using the transmitter only. I thought long and hard about this (and even posted a thread about it) on whether I should carry an SPG as well. I decided against it for now, contrary to my last post in that thread. 
I check my air very frequently. If the transmitter dies, I thumb the dive and go rent a gauge console. If my computer dies, I thumb the dive and don't dive for about 18 hours. Neither scenario is really helped by me having an SPG as a backup. A good gas management plan and frequent checks during the dive should eliminate the possibility of me running out of air even if the computer or transmitter fail during the dive.
And my buddy is never far away.
I check my air very frequently. If the transmitter dies, I thumb the dive and go rent a gauge console. If my computer dies, I thumb the dive and don't dive for about 18 hours. Neither scenario is really helped by me having an SPG as a backup. A good gas management plan and frequent checks during the dive should eliminate the possibility of me running out of air even if the computer or transmitter fail during the dive.And my buddy is never far away.
diver 85
Contributor
If it dies 5 minutes into dive 1 for the day then I don't have to wait long, but if it dies during dive 3 of the day then I have no idea what my pressure group is, because I haven't been tracking depth or time at each depth, that's what the computer is for. So I'm done for the day in that case. (Maybe not 18 hours but definitely for that day)
Depth is something that requires constant awareness. Tank pressure is something that requires only occasional monitoring for most of the dive. That's why my computer is on my wrist, and yet I don't mind a nice plain SPG.
On familiar sites, I may know the depths intuitively and not need to look much at my computer. In those cases, I might only glance at it occasionally for most of the dive just to check my times. Of course, it's not in the way or anything, so that doesn't really factor in.
What *does* factor in is doing dives in unfamiliar sites, especially dives with reduced references (such as wall dives, reef dives, drift dives, and so on). On *those* dives, having my depth right there in front of me is *tremendously* convenient, as I can check my depth (and other data) without even looking away from my references. If it's a mid-water traverse with no references, being able to keep my depth constantly in sight is worth its weight in gold (or would that be worth its buoyancy in helium). Even on a normal dive, doing an ascent with your dive data on your wrist is quite remarkably convenient.
Doing a constant-depth swim with no references requires constant instrument feedback. No similar case exists for tank pressure. (The closest I can come up with would be watching for gas supply exhaustion in an uncontrolled free flow during an ascent from a significantly deep and long dive that CESA is a bad idea and in water cold enough that a cascading freeze flow event is likely, but that's such an edge case that I don't consider it worthy of merit, and carrying appropriate redundant scuba would render it irrelevant regardless.)
On familiar sites, I may know the depths intuitively and not need to look much at my computer. In those cases, I might only glance at it occasionally for most of the dive just to check my times. Of course, it's not in the way or anything, so that doesn't really factor in.
What *does* factor in is doing dives in unfamiliar sites, especially dives with reduced references (such as wall dives, reef dives, drift dives, and so on). On *those* dives, having my depth right there in front of me is *tremendously* convenient, as I can check my depth (and other data) without even looking away from my references. If it's a mid-water traverse with no references, being able to keep my depth constantly in sight is worth its weight in gold (or would that be worth its buoyancy in helium). Even on a normal dive, doing an ascent with your dive data on your wrist is quite remarkably convenient.
Doing a constant-depth swim with no references requires constant instrument feedback. No similar case exists for tank pressure. (The closest I can come up with would be watching for gas supply exhaustion in an uncontrolled free flow during an ascent from a significantly deep and long dive that CESA is a bad idea and in water cold enough that a cascading freeze flow event is likely, but that's such an edge case that I don't consider it worthy of merit, and carrying appropriate redundant scuba would render it irrelevant regardless.)
I use a VT3 wireless and keep a spg in my reg bag.
The answer to whether you can continue diving that day is whether or not you have enough info to figure out what pressure group you are in.
Let's say you are doing multiple dives and your computer dies on the during the second dive of the day. If you downloaded dive 1 you know your BT and max depth you can figure out your ending pressure group. The next problem is the surface interval before dive 2. This is where things get dicey unless you noted the time. But lets say you know it was at least an hour and plan from that. This is a worse case plan thinking it was closer to 1.5 hours. (this is giving you safety margin) Then you have to consider dive 2. Was your buddy close to you the whole way? If yes see what his depth and time was for dive 2. Add in extra time and depth from his info again to give yourself safety margin. Based on that you have derived a final pressure group worst case multi dive profile to continue with for a 3rd dive. This can work fine as long as you put in enough safety margin.
The real point to be made here is you should have some other backups to increase your safety margin further.
1) a dive watch and a few notes on a slate can allow you to create you profile with more accuracy.
2) a depth gauge can be a redundant backup to your computer (along with #1 and you have all the info you need)
3) This is the direction I have turned to... I have a second computer as redundancy This way unless both computers die I can continue without any extra considerations or fudge factor.
So far neither of my computers has failed and I've never lost sync on both computers at the same time. I wear a VT3 on my wrist and a Atom is attach to the D ring of my BCD.
The answer to whether you can continue diving that day is whether or not you have enough info to figure out what pressure group you are in.
Let's say you are doing multiple dives and your computer dies on the during the second dive of the day. If you downloaded dive 1 you know your BT and max depth you can figure out your ending pressure group. The next problem is the surface interval before dive 2. This is where things get dicey unless you noted the time. But lets say you know it was at least an hour and plan from that. This is a worse case plan thinking it was closer to 1.5 hours. (this is giving you safety margin) Then you have to consider dive 2. Was your buddy close to you the whole way? If yes see what his depth and time was for dive 2. Add in extra time and depth from his info again to give yourself safety margin. Based on that you have derived a final pressure group worst case multi dive profile to continue with for a 3rd dive. This can work fine as long as you put in enough safety margin.
The real point to be made here is you should have some other backups to increase your safety margin further.
1) a dive watch and a few notes on a slate can allow you to create you profile with more accuracy.
2) a depth gauge can be a redundant backup to your computer (along with #1 and you have all the info you need)
3) This is the direction I have turned to... I have a second computer as redundancy This way unless both computers die I can continue without any extra considerations or fudge factor.
So far neither of my computers has failed and I've never lost sync on both computers at the same time. I wear a VT3 on my wrist and a Atom is attach to the D ring of my BCD.
Diver Dennis
Contributor
I use a D9 with transmitter and an AI Cobra. Everything tucks away nicely.
BabyDuck
Contributor
vr3, nitek plus, & spg.
Suunto Vyper with a SPG on a 24" hose.
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