96 replies to this topic

[chinacat46]

I use two Suuntos myself. The vyper and the Gekko. Both are always set in Nitrox mode. I set the Vyper to alert me when my PPO2 goes above 1.4 and the Gekko at 1.6. If the Vyper beeps I start paying attention if the Gekko beeps I wasn't paying attention. Both are wrist mount but I wear the Gekko attached to my BC on a D ring.

[Basslet]

I was looking at my profiles, and one safety stop lasted 12 minutes with all the restarts.

Not used to a computer that required you to push a button like that...is that an older model of Aladin? However having 12 mins of safety stop in NC is NOT a bad thing with so many cudas to keep you company under the boat. Or even sharks on the last dive on the last day of the Aug NC trip!

It's my first computer so I don't know how it compares with other, eg. being conservative with bottom times. It seems to be pretty liberal with no fly times. Like after 6 days of repetitive dives in Roatan, it gave me a no fly time of about 15 hours.

Aladin is considered a bit conservative compared to say Cochran or some other liberal computers. However it is the computer of choice for many technical divers on the East Coast and many NC divers. Almost all the Diver Down crew use that computer as do I.

As for no fly...your dive tables tell you the no-fly rule is 12 hours. Most people including DAN now say 18 hours and 24 has always been an additional safety margin...not a hard rule as some of us are taught. And I'm guessing you didn't do lots of deep dives in Honduras...just lots of dives. Either way...your Aladin is a great computer.

They probably have the Aladin Tec, which has more features than the Prime. But thanks for the compliment.

[Basslet]

I dive a Suunto D3 bottom timer, with a Citizen Hyper Aqualand bottom timer for a backup.

I quit using a computer about 2 years ago.

It's a personal choice, to be sure... but the point is that I think it's human nature to buy more stuff than we really need... lots of computers do lots of nifty things, and cost LOADS of money, but at the end of the day all they really do is figure dive tables. They do a great job of telling us what happened, but can't anticipate what's about to happen - only the brain can do that, so my brain is my dive computer.

I would encourage a shopper not to compare features of one computer against another, but instead compare features against what you need (NEED) it to do.

For me personally:

- I don't wanna be on a dive trip and have a transmitter fail on a hoseless unit.

- I don't wanna have to look at a console to see my depth while I'm operating my BC (both are left-handed operations), and it's difficult to do both at the same time.

- I don't want something battery powered telling me how much gas I have left.

- I want the most simple, reliable, consistent tools I can find, with the smallest number of possible failures.

Thus, I dive a simple brass and glass SPG and a simple depth gauge/bottom timer.

YMMV,

-d

When you are doing multi-level diving, with 4 or 5 dives a day, I think the computer ceases to be a luxury. Many liveaboards won't let you dive without one.

[Diverbrian]

I dive a Suunto D3 bottom timer, with a Citizen Hyper Aqualand bottom timer for a backup.

I quit using a computer about 2 years ago.

It's a personal choice, to be sure...  but the point is that I think it's human nature to buy more stuff than we really need...  lots of computers do lots of nifty things, and cost LOADS of money, but at the end of the day all they really do is figure dive tables.  They do a great job of telling us what happened, but can't anticipate what's about to happen - only the brain can do that, so my brain is my dive computer.

I would encourage a shopper not to compare features of one computer against another, but instead compare features against what you need (NEED) it to do.

For me personally:

- I don't wanna be on a dive trip and have a transmitter fail on a hoseless unit.

- I don't wanna have to look at a console to see my depth while I'm operating my BC (both are left-handed operations), and it's difficult to do both at the same time.

- I don't want something battery powered telling me how much gas I have left.

- I want the most simple, reliable, consistent tools I can find, with the smallest number of possible failures.

Thus, I dive a simple brass and glass SPG and a simple depth gauge/bottom timer.

YMMV,

-d

When you are doing multi-level diving, with 4 or 5 dives a day, I think the computer ceases to be a luxury. Many liveaboards won't let you dive without one.

David is GUE trained.

As I understand, they teach a method of depth averaging that they call "Deco on the Fly" that allows them to calculate this stuff while mid dive and keep it simple. They also do their ascents in way that allows them to come up with a minimum of dissolved gas still left in their blood.

The only reason that I went to tri-mix computer myself is because I will dive shallower dives on mix if that is what I have in my tanks. My repetitive tables are only good for a three hour surface interval or better, so without a computer I can't do two dives on a boat's two tank dive if I happen to have mix in my tanks.

If you pay attention to the standard tables, one can do the same thing though. After a certain amount of SI, the pressure group is always the same and you can wait just long enough to drop back to an "A" group. Dive again with the minutes added on to your dive from that "A" group, wait the SI out after you come up. Rinse and repeat as many times as you like for the day (that the SI's will allow you). Keep in mind that for extremely aggressive diving you may bump into O2 limits this way, so you will have to keep track of that as well.

There is no reason for a liveaboard to tell a diver trained in this manner that they have to have a computer. If it is within the diver's training, it should be allowed by the liveaboard.

[Basslet]

That is just too much math for me, especially at depth. That's the rule on a lot of liveaboards. Maybe there's been too many miscalculations that resulted in too many accidents.
I learned to dive without a computer and didn't buy one until I got nitrox certified.

[Brinybay]

What diving computer(s) do you own?

Cochran Commander, nitrox version. It's a 1998 model. The Commander model has since evolved into what Cochran now calls "EMC 20H" and "EMC 16" http://www.divecochran.com/main.html

Are you happy with it?

Yes. Had it since 1998, easy to read, I can configure it for any gas mix, can d/l info to desktop computer. Battery is user changeable.

Is it console or wrist mount?

I have it in a console, but you can also wrist mount it. I don't like having anything on my wrist when I'm diving.

Where did you buy from, and what did you pay?

I bought it new from a LDS, don't recall exactly what I paid, somewhere around $400, I think they were normally around $600. It was a discount if I turned in an old "hockey puck" computer. I didn't have a computer, a friend of mine gave me one of his old "hockey pucks".

[MrScuba02]

I have an aeris atmos ai, which has been awesome. I had one slight problem with some corrupt data on it when I attempted to download my dives, but otherwise it's been solid for me. It was weird too because I could see my dives and get the information from the dive log on the puter but I couldn't download the information. It's been on over 50 dives. The QD is great along with the compass mounted to it.

My brother on the otherhand had a Uwatec smartcom, and had a number of problems with it. I know it was recalled for a while, and he had to send his back, but we did go on a couple of trips and he blew his O-ring on the QD a few times and now doesn't use the QD anymore as a result. He's said when it worked, it was a good computer, but the hassle he's had with it, seems like a pain in the butt.

[David Evans]

they teach a method of depth averaging that they call "Deco on the Fly" that allows them to calculate this stuff while mid dive and keep it simple. They also do their ascents in way that allows them to come up with a minimum of dissolved gas still left in their blood.

...

If you pay attention to the standard tables, one can do the same thing though.

...

There is no reason for a liveaboard to tell a diver trained in this manner that they have to have a computer. If it is within the diver's training, it should be allowed by the liveaboard.

Brian's correct... I do the same basic things a computer does, but I do them in my head. It's not complicated at all to do, and actually provides some flexibility that a computer doesn't.

It's (generally) also a more conservative practice than most computers are modeled after, and I like that conservativism.

For most drift-type dives, it works out about the same (where you're at a consistent depth for most of the dive). For multi-level diving, I think there are some real benefits to diving computerless.

But just keep in mind that the computer isn't doing anything magical... you're still diving tables, only the computer is doing the table math for you, and it's doing so based on some assumptions about a variety of things. For most recreational diving, this is fine, but there's really no rocket science to this at all.

But to reiterate, my issue with the computer is that it only knows where you've been and what has happened - it doesn't know anything at all about where you're going or what is going to happen next. Only your brain knows that.

Anyway - sorry to derail the thread.

My point was that people shopping for a computer should look at what they NEED, not what some marketeer or engineer thinks might make their computer sell better against their competitors.

Figure our what you NEED, and then buy it.

[chinacat46]

Hey cool avatar looks just like you.

[Vulture]

Cochran Commander, nitrox version. It's a 1998 model. The Commander model has since evolved into what Cochran now calls "EMC 20H" and "EMC 16"

I can't wait for their EMC^2 version! Longer Bottom Times, Shorter Surface Intervals. And I'll also get to answer that age old question - "What happens to a diver traveling at the speed of light when he turns his dive light on?"

I have a Suunto Cobra, console thingee. Like it so far, but have only been diving with it twice. So I guess I have more time sitting in my room with it an the manual trying to set the date and time...

[Basslet]

Aren't you really "uploading" the info from your dive computer into your own computer? Or am I being too technical?

[David Evans]

Aren't you really "uploading" the info from your dive computer into your own computer? Or am I being too technical?

If this is directed at me, then no, you're not being too technical, but you are being pretty darned funny.

The only problem with the computer between my ears is that it hasn't been upgraded in a LONG time, it's slow to reboot, it doesn't have much storage space and it's pretty much been made obsolete by the newer models.

-d

[Walter]

But just keep in mind that the computer isn't doing anything magical... you're still diving tables, only the computer is doing the table math for you, and it's doing so based on some assumptions about a variety of things. For most recreational diving, this is fine, but there's really no rocket science to this at all.

Not exactly true. The computer is not working the tables. It is working the math on which the tables are based for several different compartments. It is also doing the match much faster and more accurately than you can do on a dive, especially when you are narced.

[David Evans]

Faster, yes, I agree. More accurately? Can't agree with that - again, because the computer is looking at historical data, rather than future data. It doesn't have the means to predict what's going to happen next in the dive.

Case in point:

I was doing a dive to about 110' (on air, no deco bottle) while carrying a Suunto RGBM Vyper a few months ago. (This, by the way, is *my favorite* computer currently on the market)

At depth, the computer began telling me that I had a 15 minute deco obligation with a ceiling of 10' (there's more to the story, but that's the salient point).

As I came shallower, I did a series of deep stops beginning at about 80' followed by a very slow ascent, and by the time I got to 30', the deco obligation had cleared from my computer.

How is this possible? I thought I had to stop for 15 minutes at 10'? That's what my computer told me after all... how could I not be bent all to heck since I didn't stop at 10' for 15:00?

What does this mean? Was the computer wrong? No - it was telling me that if I ascended directly to the surface from 110' right then, I needed to do a stop at 10' for 15 minutes. And it was right (or thereabouts, anyway).

But the computer didn't know what I had in mind for the balance of my dive.

What if I had assumed that even with my leisurely ascent, I STILL owed that stop at 10'? It would totally screw up my gas management plan, and would have caused me to abort my dive prematurely... IF I trusted my computer!

Granted, I was doing some things here that aren't recreational in nature... I was in deco, and the computer was telling me so. The whole idea is to avoid deco, right?

So the computer gave me accurate information based on what HAD happened, but it had no idea what I had in mind as part of my dive plan... again, it could only tell me where I had been. In this respect, the information the computer was giving me underwater was useless.

But the same idea is true for repetitive diving on, say, a liveaboard. The computer doesn't know what your NEXT dive(s) are going to look like... it only knows what your last dives have been. And in that respect, it has very little utility as a dive planning tool.

And by my way of thinking, if it's not giving me useful information, except for depth and time, then it's no better than a bottom timer... only it cost about 3 times as much.

Again, I dive differently than the majority of people do, so I'm not suggesting that people should toss their computers. COMPUTERS ARE GOOD. THEY ARE YOUR FRIEND. USE COMPUTERS!

I'm simply suggesting that people shouldn't spend more than they need to because of the gee-whiz factor of some gadget.

I (personally) need something that tells me depth and time, and mounts on my wrist, and (hopefully) that has user replaceable and commonly available batteries. That's it, that's all I need. So that's what I bought.

As a former dive shop owner, I would strongly encourage people to buy based on this same criteria: what do you NEED?

-d

[Basslet]

The uploading question was directed at anyone. Especially geeks.
BTW, I think your logic is faulty about the computer not knowing what kind of dive you have planned. In your example the computer compensated for the way you did the rest of the dive. It didn't tell you that you had to do the deco stop because you off-gassed on your slow ascent.
Besides, suppose your dive doesn't go exactly how you planned it? Suppose you see a nudi you have never seen before and stop for a while to take photos. You don't know exactly at what time you started shooting. So how are you going to start doing calculations in your head?
I think that's what beautiful about the computer. In the past you were tied to how the tables told you to dive and . With the computer, it can figure things out for you on the fly. I know in NC, I got wrapped up in the sand tiger sharks and looking for sharks teeth and didn't do a great job of monitoring my air consumption. And my computer is great when letting me know I'm ascending too quickly and lets me know (beep beep)