Wrist Vs. Console Computers

[Puffer Fish]

Can someone please explain the whole computer/wrist wireless thing to me? Im just a little confused... Im use to having a depth and air console but guess as im not yet into the regular diving i have not got to the computer stage yet. Im gathering that your wrist comp needs to be able to measure the air in your tank - so are u saying that if you have a wrist comp you have to have a wirelss device? With the alternative being a console as that is attached via a hose to the tank? Or do some people just use the standard console for air/depth and then have the wrist comp to measure depth/time/safety stops and log your dives? Sorry if this sounds stupid! Im one for asking stupid questions but i need to understand this - its bugging me!

I would hope there are no stupid questions...There are really two families of computers:

1. Regular dive computers...these can be put on the end of your pressure gauge, on your wrist or hung off your BC.. They just do depth and all the dive calculations.

2. Air integrated dive computers... these also measure your tank pressure and can calculate things like time remaining on the tank you are using. There are two forms of this.. regular and wireless.. withe the wireless transmitter sending the information to the computer. By there very nature, the regular ones take the place of your pressure gauge, and the wireless go on your wrist.

A lot of people who use wireless, also have a pressure gauge.. just in case. If something is going to break, that is most likely the one that will. I use a scubapro wireless, and have a regular gauge as a backup...and I have had mine stop working three times.. but I have a lot more than 100 dives on the system.

If asked what I think is the ideal system... it would be a standard air integrated unit..having all the information together is nice... knowing how your air consumption compares to you no deco time is nice and they seem to be very reliable.

However, one does not "need" air integrated..

 

[tedwhiteva]

I too use a wrist wireless - VITEC DS - with a backup SPG clipped to the waist. BUT thats only because I have the SPG from tech diving. Think about what you're going to do if the computer fails? I think the word ABORT is appropriate. So hopefully there is enough gas to do that, so why worry about being able to monitor gas when you're headed home early?

Just a thought

 

[peterbj7]

Thanks Peter,

One more question - do you just have an SPG or do you have a depth gauge as well to back up your computer?

When I used an air-integrated computer (hose mounted) I also had a SPG, though nowadays I probably wouldn't bother. I always have a pretty good idea what my tank holds and I don't need to know in real time.

I've never carried a separate depth gauge, and I'm trying to analyse why. This question arises of course regardless of whether the computer is air-integrated. If I'm on a more substantial dive I usually carry two computers, so each acts as backup for the other. I've only ever once had my sole computer go out on me, and that was just a few months ago. I knew the area i was diving in, so though I felt rather naked having nothing on me to tell the depth it wasn't actually a problem. The safety stop was slightly more of an issue, but there were other people around and I just took my cue from them.

That was the first time that computer's battery had failed, and it was remarkable how suddenly it happened. There had been no indication previously that the battery was on its last legs, but just after reaching depth on that dive the whole thing just went out. A completely blank display. The battery had lasted four years and I replaced it myself at nominal cost, but a little warning would have been nice. That was a DiveRite Nitek+, a model no longer made. But I'd still rather have it than my Suunto Stinger - even though that gives me several dives' warning that the battery is on the way out, I can't replace it myself and have to send the whole thing to Suunto in another country. A very costly nightmare.

Back on the subject of wireless-integrated computers, don't forget that there are two batteries, one in the transmitter and one in the computer. The wireless transmission puts quite a load on these batteries and they tend not to last very long. In my experience you'll be extremely lucky if you manage to find either battery (they're often not the same model, and they're usually obscure) in most dive locations, and certainly never on a liveaboard. No matter how fresh you may think the batteries are ALWAYS carry a spare for each (kept in a plastic bag sealed in a dry environment), and ensure you know how to fit it (and have the necessary tools with you). Of those few people I have come across who had replacement batteries with them, one didn't have the transmitter battery (the one more likely to fail) and two others had the batteries in their original cardboard packaging loose in a dive bag where they had become slightly damp and had shorted out.

I'm sure I don't need to say this here, but it is your responsibility as a diver to ensure all your equipment is going to remain in good working order for the duration of your trip. It's astonishing how many people think that getting a computer working again is the responsibility of the dive operator. We'll obviously do all we can to help, but the last time someone needed a battery for one of these I phoned around and that battery simply wasn't available anywhere in the country of Belize. It had failed on the diver's first dive with us, having been packed away at home for some months since the previous trip slowly running down.

The other concern is that there are some unreasonable divers out there (not ScubaBoard members, I'm sure!) who expect their divemaster to change the battery for them and then blame him if the computer leaks afterwards and is destroyed. For that reason you'll find many divemasters won't help, even though they may use the same model computer themselves and change their own battery. Don't blame him - blame the unreasonable person who came before you.

 

[diverbob]

I've been diving wrist mount air integrated since OW class. I started with the AirZ, then the Smart Z and Smart Tec, all air integrated. The only time I have ever has an issue with losing tank pressure is when I was playing with a DPV. I like having my pressure, and everything else I want or need right there. I do look at my pressure very often, along with depth and time. When I was a fairly new diver, my buddy had a mask issue, and called the dive basically with no mask. I was able to secure him with my right hand on his BC, and watch the depth while ascending slowly. I didnt even think about it until he brought it up the next day, that would have been more difficult to make that ascent, while maintaining control with a console. I have been hooked on the wrist mount ever since.

 

[peterbj7]

Do you know why you check your air pressure "very often"? Is it simply because you can, or because of some insecurity caused by high consumption or whatever? I always check mine before I get in (obviously), after 5 or 10 minutes to make sure there isn't anything wrong, then on a normal recreational dive maybe once or twice more, the last time being just before final ascent. Obviously if it's getting low I check it more often, but on most recreational dives I make that isn't an issue.

I don't even check depth that often either when I'm diving on familiar territory. The main times are at the lowest point of the dive (especially with students), when I'm looking for a moored boat and I know the depth of the mooring, and to establish/maintain a safety stop depth. There are so many visual clues here in relatively clear water on reef dives that a depth gauge is almost redundant.

On my computer the number that I pay most attention to is my remaining no-stop time, and once that's dropped into single digits (or gone into deco) I look at it every few minutes. But I still try not to be fixated on it.

 

[Puffer Fish]

The wireless transmission puts quite a load on these batteries and they tend not to last very long. In my experience you'll be extremely lucky if you manage to find either battery (they're often not the same model, and they're usually obscure) in most dive locations, and certainly never on a liveaboard. No matter how fresh you may think the batteries are ALWAYS carry a spare for each (kept in a plastic bag sealed in a dry environment), and ensure you know how to fit it (and have the necessary tools with you).

I would bet my average battery life on the transmitter is something around 30 dives... might be more, but not a lot.

 

[Puffer Fish]

Do you know why you check your air pressure "very often"? Is it simply because you can, or because of some insecurity caused by high consumption or whatever? I always check mine before I get in (obviously), after 5 or 10 minutes to make sure there isn't anything wrong, then on a normal recreational dive maybe once or twice more, the last time being just before final ascent. Obviously if it's getting low I check it more often, but on most recreational dives I make that isn't an issue.

I don't even check depth that often either when I'm diving on familiar territory. The main times are at the lowest point of the dive (especially with students), when I'm looking for a moored boat and I know the depth of the mooring, and to establish/maintain a safety stop depth. There are so many visual clues here in relatively clear water on reef dives that a depth gauge is almost redundant.

On my computer the number that I pay most attention to is my remaining no-stop time, and once that's dropped into single digits (or gone into deco) I look at it every few minutes. But I still try not to be fixated on it.

If you dive the same areas over and over again.. after a while, you could do them without any computer or gauges... I've done a few thousand dives with just a j-valve and a depth gauge..just dive till you cannot breath.. pull the lever and head up.

But dive with a insta-buddy... and I take the time to determine who's profile we will be diving...usually their's, but every so often I'm the big air user

Dive on a live aboard, making 5 or 6 dives a day, and if your computer breaks or the battery dies, you may be sitting out a very expensive day. For that reason, I dive with a spg... and a backup depth gauge (ok, it is built into my citizen watch, but it is still a depth gauge)...something breaks and I am still diving.

Note: Having tables with you is sort of necessary, if you take the approach.

 

[TSandM]

For me, the nicest thing about having my computer on my wrist is not that I can easily see it (although that's a good thing) but that looking at it doesn't require me to do anything with my hands. I can easily, for example, be spooling up the line from a bag I've shot, and still monitor my depth. To do that with a console, I'd have to do something like clip it across my chest, and as my dive buddy of the other night found, doing that, carrying a lanyard light and a camera makes for a real spiderweb of stuff that's hard to manage.

When I had my depth gauge on a console, I put it on a retractor so it wouldn't drag, and that meant I had to drag it out in front of me to look at it, which was frequently quite inconvenient as I was dumping gas from my BC or something else that needed my hands.

If you are determined to get air integration, doing it with a wrist computer is substantially more expensive. As far as I can tell, the only real advantage of air integration is that, when you download your dives, you automatically enter the gas consumption information into your log. Other than that, having a digital readout of pressure is more accuracy than I need, and calculating remaining gas time at this depth is something I can do myself, if I want to.

 

[lmorin]

I can see why wrist mount gear is convenient, as is my watch. But, my console carries 3 separate items: SPG, computer and compass. Any of them would be fine on my wrist, but all three gets a bit crowded, IMHO. I clip my console to a spot I custom-created on my upper left-central chest, not far from my chin. It is an 8-12" retractor stretch to see it comfortably.

 

[TSandM]

Compass is on my left wrist, gauge is on my right, and SPG is on my waist. Since I refer to the SPG least often and can do so very much at my convenience, it's not a problem to unclip it.