Incident due to battery change on dive computer

[stuartv]

Tables, second PDC, math, etc. They are all possible tools to implement. The big issue is the OP really approached (or likely crossed) a very potentially deadly line and DID NONE OF THE ABOVE!!!!!

I don't think that is correct, and that really gets to one of the corollaries to my main point.

He said he DID use tables. He just used them incorrectly. He based his decision-making on consulting an NDL table using his average depth, instead of his max depth. Which brings out a question I already asked: If you insist on teaching tables to an OW student, knowing that they are very unlikely to ever use them - and if they do, it could easily not be until years later - is it really good to teach them? Or is it better to recognize that rusty, old, unused knowledge is just as likely to breed misplaced confidence (as in the case of the OP) and result in a bad outcome?

You teach tables. Diver doesn't use them for years and then one day his DC dies on his first dive and he decides to fall back on his knowledge of the tables to still do his second dive. As far as the diver knows, to the best of his (hazy) memory, he does everything correctly. Worst case: He gets bent.

You don't teach tables. Diver goes along for years and then one day his DC dies on his first dive. He falls back on his training and does the only thing he can do. Sit out the rest of the day and rent a computer for tomorrow (if he can). Worst case: He is fine.

Note that both cases above are based on the diver following their training to the best of their ability. This is not talking about divers who willfully and purposely choose to do something that goes against their training.

We can argue all day about the merits of requiring training in deco theory, whether it's as basic as teaching tables or as advanced as the DP course. None of that will change the fact that knowledge which goes unused for years does not stay fresh and ready-to-use in a person's mind - even though the person may THINK they still remember it accurately.

So, again, making somebody learn something that you know they are not going to use ever, until possibly years down the road when the shtuff hits the fan, is just asking for trouble. It's asking for (some) people to have unwarranted confidence and engage in behaviors that they should not. Like the perfect example of the OP in this specific incident.

If someone came to you and wanted to learn to shoot, so they could carry a concealed weapon, would you teach them to shoot and then tell them it's okay to start carrying now and they never need to actually shoot their gun again. They'll be just fine if they suddenly need it 10 years down the road and they have not shot it since they first got it? Or would you tell them they need to get out to a range on a regular basis and practice with it? And if you KNEW that they were never going to ever go to the range to practice; they were just going to carry it every day and never shoot it, would you condone them even getting it and starting to carry it in the first place? Personally, I would not.

If you choose to stake your life on a skill, it should not be a skill that you learned years ago and never used in any way since then. The person with a gun that only had 2 days of training, 10 years ago, and never even practiced with it since is WAY more likely to be a hazard to themselves then they are to successfully use their gun to a positive end. It seems like teaching tables is pretty similar. If the person isn't going to maintain any proficiency after their initial training, it seems to me that it would be better to just not give them the training at all, so they don't hurt themselves when they get in a crunch.

 

[rhwestfall]

Stewart, I don't give a s*it about the discussion of using tables, which you can't apparently get past. What I care about is he made a dive unprepared/unplanned, did a poor job monitoring the dive until it was "too late", didn't follow proper procedures when presented with an issue (ignored valid information), then made an error in analyzing it on his SI, and followed it up with another dive with what seems to be all of the same things repeated... quite frankly, all in simple violation of the basic guidelines of diving.

Numerous options to handle this, included your "second" pdc are appropriate options. The whole issue is he really did the whole thing half a$$ed, and is "blaming" it on the computer and a DM.... in reality, with the OP's reported dive count, "practice" is in the realm of almost constant. He apparently chose to not "practice"...

 

[stuartv]

I got my Deco for Divers from BookDepository.com (i believe it is a UK website) and it arrived in NYC in 5 days. I usually like kindle versions as well but for my diving books I am liking more the printed versions.
Deco for Divers: A Diver's Guide to Decompression Theory and Physiology : Mark Powell : 9781905492299

PS - I am not related to this website, but I was extremely pleased with their service, though price of the book is not exactly cheap...

Thanks for that! I have ordered it. And it was cheaper than Amazon!

---------- Post added April 14th, 2015 at 11:02 AM ----------

Stewart, I don't give a s*it about the discussion of using tables

rhwestfail: Then my comments are not directed at you. They are intended for the people who have been saying that "if he knew how to use tables, he wouldn't have had this problem" or variants thereof.

---------- Post added April 14th, 2015 at 11:04 AM ----------

Numerous options to handle this, included your "second" pdc are appropriate options. The whole issue is he really did the whole thing half a$$ed

Agreed!

 

[Storker]

He said he DID use tables. He just used them incorrectly. He based his decision-making on consulting an NDL table using his average depth, instead of his max depth. Which brings out a question I already asked: If you insist on teaching tables to an OW student, knowing that they are very unlikely to ever use them - and if they do, it could easily not be until years later - is it really good to teach them? Or is it better to recognize that rusty, old, unused knowledge is just as likely to breed misplaced confidence (as in the case of the OP) and result in a bad outcome?

You teach tables. Diver doesn't use them for years and then one day his DC dies on his first dive and he decides to fall back on his knowledge of the tables to still do his second dive. As far as the diver knows, to the best of his (hazy) memory, he does everything correctly. Worst case: He gets bent.

You don't teach tables. Diver goes along for years and then one day his DC dies on his first dive. He falls back on his training and does the only thing he can do. Sit out the rest of the day and rent a computer for tomorrow (if he can). Worst case: He is fine.

Note that both cases above are based on the diver following their training to the best of their ability.

No, they're not. A diver "following their training to the best of their ability" keeps their knowledge current if they're planning to use that knowledge. That's the diver's responsibility, not the instructor's.

knowledge which goes unused for years does not stay fresh and ready-to-use in a person's mind

And whose responsibility is it to use the knowledge so it stays fresh and ready-to-use in a person's mind?

So, again, making somebody learn something that you know they are not going to use ever, until possibly years down the road when the shtuff hits the fan, is just asking for trouble. It's asking for (some) people to have unwarranted confidence and engage in behaviors that they should not.

No, it's treating adults as adults. I'd be seriously pi$$ed off if my instructor told me "I'm not going to teach you this, because I don't trust you to keep that knowledge current, and yu may behave like an idiot and get hurt. So I'll treat you like a child and just teach you the 'dummies' version".

If someone came to you and wanted to learn to shoot, so they could carry a concealed weapon, would you teach them to shoot and then tell them it's okay to start carrying now and they never need to actually shoot their gun again.

Straw man argument. No-one here (except you) is saying that instructors should teach tables and then tell them it's okay to never actually use their noggin again.

If you choose to stake your life on a skill, it should not be a skill that you learned years ago and never used in any way since then.

Thank you, Captain Obvious.

If the person isn't going to maintain any proficiency after their initial training, it seems to me that it would be better to just not give them the training at all, so they don't hurt themselves when they get in a crunch.

Which - sadly - is what the agencies are doing these days. I took a nitrox class this winter; I had to order the tables separately, because they weren't taught anymore. I chose to opt for tables, and - *drum roll* - I choose to use those tables regularly to keep my knowledge of them current


You seem to argue that diving theory more advanced than "follow your computer, it'll take care of you" shouldn't be taught to rec diving students, because they'll sure as heck forget almost everything, and hurt themselves. Is that right?

 

[victorzamora]

You seem to argue that diving theory more advanced than "follow your computer, it'll take care of you" shouldn't be taught to rec diving students, because they'll sure as heck forget almost everything, and hurt themselves. Is that right?

This seems to be the only consistency in his arguments. The biggest issue, however, is divers like OP completely ignore their computers ANYWAY.....and then blame locking out their computer on changing the battery. With some people, you really can't win. The moral of THIS particular story is that you need to follow the plan you've established. If you're blindly following a single computer, that's fine....but you live with the repercussions, including skipping a few dives when you lock it out or kill the battery.

 

[stuartv]

You seem to argue that diving theory more advanced than "follow your computer, it'll take care of you" shouldn't be taught to rec diving students, because they'll sure as heck forget almost everything, and hurt themselves. Is that right?

You're almost there. What I am saying is that the way things are taught now - the reality, not the How-It-Should-Be fantasy land - is that PADI and SDI (at least) are NOT teaching tables and telling students to use those and don't use a computer. They are either teaching tables and how to use a computer or they are just teaching use of the computer. Because I am Captain Obvious, I will point out that that means the vast majority of fresh OW cert divers are going to go diving just using a computer and never bother with tables again. Most of them are not fine specimens like yourself who put additional time into looking at a table that says they have an NDL of 25 minutes just before they go do a 45 minute NDL dive using their computer.

Given this reality, I am speculating that the statistics for people with nothing more than OW training would show a better safety record for people who were taught how to use a DC and not taught tables than for people who did have training in use of tables. That is in substantial part because in Reality (not How-It-Should-Be land), people make mistakes. Mistakes like "I use average depth when I consult this table, right?" Training that does not recognize and accommodate the POTENTIAL for mistakes as much as possible is flawed training. If people commonly make the same mistake when engaging in process X, then the training for process X should accommodate that in some way to mitigate the risk, or process X should be modified to so that the mistake is no longer common. It's a lot easier to make a mistake in calculating your NDL using a table than it is to figure out your NDL by reading it off your computer screen.

The OP is an example (Captain Obvious: "It's just one single data point") that supports my speculation. If you have any basis for refuting my speculation, please spell it out. Remember, my speculation is specifically limited to people who have no training beyond OW.

---------- Post added April 14th, 2015 at 12:11 PM ----------

The moral of THIS particular story is that you need to follow the plan you've established. If you're blindly following a single computer, that's fine....but you live with the repercussions, including skipping a few dives when you lock it out or kill the battery.

And I have been saying the same thing all along - and responding to the people who have asserted that after he bent his computer, he could have used knowledge of tables and deco theory (which he apparently does not have training for) to still do his second dive. I specifically responded to at least two people (I think) who asserted that, and I asked what tables they were using to determine that the guy could have done a second dive and neither one gave me an answer or an "oh, you're right. Never mind."

 

[victorzamora]

And I have been saying the same thing all along - and responding to the people who have asserted that after he bent his computer, he could have used knowledge of tables and deco theory (which he apparently does not have training for) to still do his second dive. I specifically responded to at least two people (I think) who asserted that, and I asked what tables they were using to determine that the guy could have done a second dive and neither one gave me an answer or an "oh, you're right. Never mind."

I'll discuss the rest when I get a chance. However, with proper knowledge of tables you CAN do a second dive after you lock your computer during the first one. Maybe not the OP's profile, but the general theory remains. I did a dive on 32% with my computer set to air. Bent the computer (I knew I was going to as I had my NDLs planned) and did the next dive on tables. Without knowing tables, I would've been done for 24 hours.

However, the bulk of my point remains that OP screwed up because he screwed up (I don't want to use the word "moron")..... he would've screwed up tables as badly as he did computers. Anybody that screws up such basic rules can't be expected to follow ANY accurately. Worst part? He comes on here claiming it's the BATTERY'S fault he didn't keep an eye on his computer. There are undeserved hits in the tech world. This is the opposite. OP went far out of his way to get bent and was lucky enough to walk away.

 

[stuartv]

I'll discuss the rest when I get a chance. However, with proper knowledge of tables you CAN do a second dive after you lock your computer during the first one. Maybe not the OP's profile, but the general theory remains.

Yes, I understand that. I was responding to people who specifically were talking about the OP and his specific case.

However, the bulk of my point remains that OP screwed up because he screwed up (I don't want to use the word "moron")..... he would've screwed up tables as badly as he did computers.

And he did. He DID use tables. And screwed up badly. But, as I've observed already, it SEEMS as though he understood his computer well enough that, if he had been using a backup DC that was set as he expected it to be, he would very likely have had a good second dive, without exceeding any limits. Note that he did TRY to do what you alluded to, by consulting the tables after his first dive. And did try TRY to follow a computer on his second dive - it was just a VERY WEAK try, in that his effort consisted of going by his DM's computer and allowing/trusting the DM to read it for him.

 

[victorzamora]

You're almost there. What I am saying is that the way things are taught now - the reality, not the How-It-Should-Be fantasy land - is that PADI and SDI (at least) are NOT teaching tables and telling students to use those and don't use a computer. They are either teaching tables and how to use a computer or they are just teaching use of the computer. Because I am Captain Obvious, I will point out that that means the vast majority of fresh OW cert divers are going to go diving just using a computer and never bother with tables again. Most of them are not fine specimens like yourself who put additional time into looking at a table that says they have an NDL of 25 minutes just before they go do a 45 minute NDL dive using their computer.

What about an individual that takes the "additional" time to track one's own computer real-time during the dive?

Given this reality, I am speculating that the statistics for people with nothing more than OW training would show a better safety record for people who were taught how to use a DC and not taught tables than for people who did have training in use of tables. That is in substantial part because in Reality (not How-It-Should-Be land), people make mistakes. Mistakes like "I use average depth when I consult this table, right?" Training that does not recognize and accommodate the POTENTIAL for mistakes as much as possible is flawed training. If people commonly make the same mistake when engaging in process X, then the training for process X should accommodate that in some way to mitigate the risk, or process X should be modified to so that the mistake is no longer common. It's a lot easier to make a mistake in calculating your NDL using a table than it is to figure out your NDL by reading it off your computer screen.

I think you're projecting your training on everybody else. I didn't touch a table for like 6 years and I still remembered how to use mine. It's really not that complicated....and it even has the instructions on the table! That was as an OW-only diver, recreational-only. VERY few dives, fairly infrequent.

---------- Post added April 14th, 2015 at 03:10 PM ----------

And he did. He DID use tables. And screwed up badly.

If you actually LOOK at the PADI RDP, you'll see that the NDL for a 70ft MAX depth dive is 40min on air. Regardless of Max vs. Avg depth, he broke EVERY standard regarding tissue tracking. A "bent" computer means 24 hours of no diving. As a computer diver, he should know that. Exceeding NDLs on the Tables by 6 minutes (as he thought he did) means a 15ft stop for 15 minutes minimum is urged and a 24-hour dry period is required. Not only should any tables-diver know this, the tables CLEARLY say it....written write on the face of the tables!

Trying to follow his DM's PDC on his second dive ALSO breaks the rules on computer diving. Follow your own, not your buddy's. They're not diving the same profiles as you. Were he capable of following ANY rules he wouldn't have made the second dive.

 

[NAM001]

I believe you are right about being cut and dry. But to be so means you have to use the table as designed,,,, square profile diving. It has been long acceptable to use the timed average depth as bottom depth. the rule of thumb for new divers was to use max depth for bottom depth. So if you did a dive from 90-100 ft (nearly pure square profile) you used the deepest depth for planning. Toidays multilevel diving make the tables unusable for most hence the realtime computers.

My education on tables must not be as good as I thought. Because from what I know of how to use the tables (PADI RDP, NOAA, or USN), it IS cut and dried. If you went to a max of 93', then your NDL is 25 minutes (or close, depending on which table you actually use). I haven't yet learned about a table based on average depth. What agency teaches that in their OW class?

---------- Post added April 14th, 2015 at 12:45 AM ----------