Are dive computers making bad divers?

[Patoux01]

;7563502 (and that is, IIRC, an actual quote from this thread, while I haven't seen anyone claiming outright that tables guys are superior).

Now maybe there's such thing as a language barrier, but here goes:

If you cant work a table you are diving trust me dives.

Don't get me wrong, I have nothing against people using tables. I simply have something against those that think that you need to use tables to understand how deco works...

 

[jonhall]

"Are dive computers making bad divers?"

From a more simple-minded, recreational diver, I like the analog gauges, but also like technology.

Would say that the dive computer has led me to think more about my diving profile (up and down) and especially my ascent rate and not coming up to fast. Probably wouldn't have thought to much about it with analog as there were no alarms sounding to let me know I was possibly doing something wrong. Also wouldn't have thought much about the NDL before, because I wasn't pulling a dive table out between dives. Would have depended solely on the dive master.

So, on one of my recent dives (1st dive: 44 min with max of 74'; 2nd dive: 65 min with max of 54') my computer was sounding the alarm on my second dive as I had one ascent warning during a stretch were I ascended about 32' in about 2 minutes, to a depth of 19' (the warning came as I ascended 9' in 20 seconds), and it said I was ignoring my decompression stop. I was at the right depth for the stop, but the computer wanted me to stay there longer than 3 min. Knowing there are other factors involved than just the ascent rate, I would up with a permanent error message and my computer was then locked for a few days until it cleared. Can't say I would have been aware of any problems without the computer and I would be as happy as a lark! But knowing I did something wrong, I had all these thoughts of bad stuff going on with me. Thoughts of DCS went through my mind as a rash broke out in the crease of my elbow! Later on, I remembered that I actually wrapped my arm around the ladder to hang onto because a big wave came by, I calmed down a bit.

But seriously, for me, the dive computer, if for nothing else, has made me think more about safety.

 

[phoenix31tt]

Its not a mater of superiority for me. It is a matter of understanding your tool when it is right and when it wrong. The computer is only as right as it is set up to be. Set it up wrong and it serves you wrong, and it will do so at the wrong time. I have had the incorrect nitrox setting nearly bite me before. Its all about check and ballance. Or perhaps trust but verify.

and if you have your depth wrong on a table... what about getting the nitrox value wrong from your analyzer, or how about your dive timer/watch or whatever you use being off, or failing during the dive without you noticing? Or get this, what if you THINK you are using your table correctly but you are absolutely wrong about it... much worse than a computer telling you what to do right?

there are many other ways of cross referencing your dives without using a table... you can use another computer, you can use a computer program (be it a dive simulator or a computer training simulator)...

knowing how to PROPERLY use a table or a computer is a necessity for safe diving... if you know how to properly use one and not the other, it changes nothing.

p.s. there are other "old guys" that are using computers just fine... so lets not get into the we are old because we learn the basics through the years....

the basics one would've learned 20 years ago would be outdated and not apply due to the experience gained over the last 20 years.... if we wouldn't have learned from our experiences and developed new ways of doing things (new basics) we'd still be stuck in the dark ages.

I have nothing against people who know how to properly use tables and dive safely with them, that's fine. Just don't think that people who know how to properly use computers are somehow unsafer divers or something because guess what... before computers became mainstream people were trained to use tables and were still just doing trust me dives led by dms, they don't even bother to double check it because the DM knows what he's doing, he's been doing it for years and I don't get bent.

 

[TMHeimer]

More good points. Sounds like blowing my own horn, but of course you have to read the tables correctly--and re-check to be sure. Computers are machines, so unlike tables you have both the possibility of human and electronic failures. I haven't ever had my computer beep on ascent, but from the start I ascended slowly using my watch and gauge as taught in OW. As far as one or the other helping me be "safer", I don't think so. After the physics and physiology parts of the "old" DM course our instructor asked if we now thought differently about our own diving, now having this great knowledge. I thought no--I learned what shouldn't be done in OW, just not all the details of exactly why.

 

[Eric Sedletzky]

More good points. Sounds like blowing my own horn, but of course you have to read the tables correctly--and re-check to be sure. Computers are machines, so unlike tables you have both the possibility of human and electronic failures. I haven't ever had my computer beep on ascent, but from the start I ascended slowly using my watch and gauge as taught in OW. As far as one or the other helping me be "safer", I don't think so. After the physics and physiology parts of the "old" DM course our instructor asked if we now thought differently about our own diving, now having this great knowledge. I thought no--I learned what shouldn't be done in OW, just not all the details of exactly why.

Computers are machines and tables are not, but there is a machine component to tables both in the depth gauge and the timing device, both of which can fail. A simple bottom timer could run out of juice making depth and time info gone. A watch could do the same thing. A needle depth gauge could stick or be inaccurate, I've seen it happen.

There are no 100% guarantees either way, something could fail somewhere at some time. We just live with that as divers.
I choose the best option for simplicity and reduced bulk. For me this means a wrist computer with a fresh battery and no backup for the simple moderate depth dives I do. If I began once again to do deeper more aggressive dives then I would buy a second computer. It would be easier and less bulky to me to have only one thing rather than two additional things plus running tables. And as far as getting a BT and running tables in my head as a backup, why not just get something like a Puck, they are cheaper.

Computers are here to stay and are the new norm, tables are obsolete.
Just like cars, a new driver doesn't need to learn how to drive in a Model 'A' to be a good driver.

 

[phoenix31tt]

Computers are machines, so unlike tables you have both the possibility of human and electronic failures.

while tables can't fail like a computer can, your bottom timer/depth gauge could (less likely if it's analog and doesn't use a battery) but still they can and do fail.

In addition to that, I've yet to see any reports of a computer giving WRONG information though, it's either it's working or it's not (AI computers not included). There comes a point in technology where a product developed enough that it reaches a point where it becomes so robust that it doesn't need to be verified or double checked by manual methods. I wouldn't dive with a j-valve for fear that my spg would fail and kill me.
In that way, for recreational diving, i wouldn't cross reference anything with a table for fear that my computer would fail and kill me...

---------- Post added December 3rd, 2015 at 03:07 PM ----------

eric beat me to it

 

[TMHeimer]

I don't disagree with either of you. There's always some risk and you do what you feel best with. On deep dives my Puck and analog stuff is good for me. And of course analog stuff can fail as well, as did my SPG getting stuck at 1000 PSI, requiring a new one. I did have a feeling something was out of whack knowing my bottom time (though be it at 30' or less) and where my PSI should really be at. I must admit I also haven't heard of a computer giving wrong info. (wonder if that does happen?) instead of just failing. Whatever you feel comfortable with is good. I'm not comfortable storing important stuff on my laptop, and when practical, make hard copies--including music (my own playing) on discs/tapes instead of stored digitally (prefer disc as tapes may fail over time). My log book is paper, with Xeroxed copies stored in our "fire box". Maybe tables just sort of represent hard copy to me, for some unknown reason.

 

[DarinJ]

I've read a few threads about this debate (computers vs. tables) and the same point keeps coming up: "Tables can't fail. Computers can fail. If your computer fails, you won't know your remaining ndl time unless you have tables for backup." My thought has always been that if any major piece of gear fails, I abort the dive. Of course, I don't do commercial diving, safety diving, deco diving, or anything other than recreational diving.

If my computer ever fails, I don't die; I tell my buddy that something is wrong and we ascend to the surface. I use my buddy's computer to time my safety stop--or I could count off 180 seconds if I ever have to finish a dive without my buddy. Since I never dive past my ndl while the computer is working, I never have to worry about time remaining if the computer fails during a dive.

Am I missing something here? If I am diving within my NDLs and have a computer failure, I abort and surface with no need to worry about NDLs because I know I was within those NDLs when the computer failed.

Of course, a diver who doesn't check his computer regularly wouldn't know when the computer failed and then could unintentionally stay too long at depth, but that diver also wouldn't be checking his bottom timer or pressure gauge often enough either (& I wouldn't be diving with anyone like that). The computer doesn't make him a bad diver--he's a bad diver whether he uses a computer or tables & timer.

 

[boulderjohn]

I've read a few threads about this debate (computers vs. tables) and the same point keeps coming up: "Tables can't fail. Computers can fail. If your computer fails, you won't know your remaining ndl time unless you have tables for backup." My thought has always been that if any major piece of gear fails, I abort the dive. ...

Am I missing something here? If I am diving within my NDLs and have a computer failure, I abort and surface with no need to worry about NDLs because I know I was within those NDLs when the computer failed.

Yes, you are missing something here.

You are missing the fact that if you are using dive tables rather than a computer, you don't just use a dive table. You have to have some way to measure depth and time, and both of them can fail as easily as a computer. In fact, the only instrument I ever had fail me under water was a dive watch, and fortunately that watch failed me in a swimming pool. Most importantly, it failed me by stopping for a while than going again, so I had no idea it had failed. I was teaching a class at the time, and I was using it to judge when I had to get the students back to the surface to begin the next session of the class. When I got to the surface, I looked at the wall clock and realized my watch had somehow lost 10 minutes while I had the class in the deep end of the pool. If I had been using a computer instead, the screen would have gone blank on a failure, and i would have known something was wrong. Using the watch, the only way I knew something was wrong was when I saw the wall clock.

If I had been using that watch with tables during a dive, i would have spent 10 more minutes at depth without realizing it, and I probably wold have gotten DCS.

 

[DarinJ]

Yes, you are missing something here.

You are missing the fact that if you are using dive tables rather than a computer, you don't just use a dive table. You have to have some way to measure depth and time, and both of them can fail as easily as a computer. In fact, the only instrument I ever had fail me under water was a dive watch, and fortunately that watch failed me in a swimming pool. Most importantly, it failed me by stopping for a while than going again, so I had no idea it had failed. I was teaching a class at the time, and I was using it to judge when I had to get the students back to the surface to begin the next session of the class. When I got to the surface, I looked at the wall clock and realized my watch had somehow lost 10 minutes while I had the class in the deep end of the pool. If I had been using a computer instead, the screen would have gone blank on a failure, and i would have known something was wrong. Using the watch, the only way I knew something was wrong was when I saw the wall clock.

If I had been using that watch with tables during a dive, i would have spent 10 more minutes at depth without realizing it, and I probably wold have gotten DCS.

That was exactly the point I was trying to make. If I check the computer and see remaining allowable bottom time of 15 minutes (for example) and then check my computer 2 minutes later and see that it has failed, I know that I have 13 minutes before I need to worry about deco. I don't dive those 13 minutes at depth; I take less than 1 minute to signal my buddy that my computer has failed and we begin our ascent. We finish the diver earlier than planned, but I can be certain that I am not over my NDL for that dive.

Diving without tables & a timer with me doesn't make me less safe. Being a safe diver means I'm using the equipment I have properly and safely.