Incident due to battery change on dive computer

[lowviz]

...//... 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."

*sigh* If you insist.

V-Planner gives you a half hour of deco for a 93' 46m dive on air when set to most aggressive. You get an hour and ten minutes deco on most conservative. So the OP's assertion that the 28 min of deco he blew off wasn't really deco is plausible.

Let's give him the benefit of his extensive experience and believe that his dive can be done within NDL limits. So we pull out the tables and penalize him with a 100 ft dive for 50 minutes and give him credit for doing the deco. His penalty is that he is now a NOAA "L", an hour and 45 min later he is an "H".

Go back to 93 (100 ft)? Nope, he has an RNT of a half hour. Forget it.

He did an 80 foot dive for his second dive. He has an RNT of 38 minutes there, forget that too.

He could, however, stay above 60 feet and do a second 20-30 minute dive. Me, I'd pass on it.


His second dive was nothing short of dancing with disaster.

 

[RJP]

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.

Could that be you projecting your own, limited experience with your preferred shop/instructor/agency?

I'm also wondering how someone with one OW card, from one agency, and a handful of dives thinks they can speak credibly to "the way things are taught... the reality" about anything having to do with diving.

Also inter interesting that you throw PADI in there. I'm pretty sure you have zero experience with PADI courses in any way. Even if you did, you need to keep in mind that "the reality is" that no agency teaches anything. Instructors teach courses, tables, computers, etc. PADI offers OW Crew Packs with printed tables, ERDPm electronic tables, and "computer" crew packs. Any instructor/shop who wants to can order the "tables" version.

 

[stuartv]

I think you're projecting your training on everybody else.

Actually, I thought I was projecting the OP's documented behavior.

Could that be you projecting your own, limited experience with your preferred shop/instructor/agency?

I'm also wondering how someone with one OW card, from one agency, and a handful of dives thinks they can speak credibly to "the way things are taught... the reality" about anything having to do with diving.

Also inter interesting that you throw PADI in there. I'm pretty sure you have zero experience with PADI courses in any way. Even if you did, you need to keep in mind that "the reality is" that no agency teaches anything. Instructors teach courses, tables, computers, etc. PADI offers OW Crew Packs with printed tables, ERDPm electronic tables, and "computer" crew packs. Any instructor/shop who wants to can order the "tables" version.

Right. Pick on my published credentials instead of identifying what part of my speculation you think is actually incorrect. Are you asserting that I am wrong and that there are PADI instructors who teach only tables and teach their students to not use dive computers? That is the assertion that I made, that you quoted.

RJP, you post a lot of really great stuff. I really respect and value the professional, analytical, and extremely educated and intelligent basis that is part of your normal postings. I am surprised that you would turn to a personal attack instead of responding to the assertions I made or the speculation I attached to them.

 

[rivers]

Actually, I thought I was projecting the OP's documented behavior.



Right. Pick on my published credentials instead of identifying what part of my speculation you think is actually incorrect. Are you asserting that I am wrong and that there are PADI instructors who teach only tables and teach their students to not use dive computers? That is the assertion that I made, that you quoted..

I know of at least 2 dive shops that still teach the tables in the PADI OW course (on the new style course). I have seen several more at the inland site I work at also teaching tables on the PADI course

 

[Shasta_man]

While checking against the tables is an excellent idea, judging by my experience of never seeing anyone consult a set of tables, I'm thinking the actual percentage of rec divers that do that would horrify some of those here.

 

[Storker]

I guess I'm an outlier, then. If I'm planning one of my standard profiles, I check neither tables nor my DC's planning function, because I've done it so many times before. But if I'm planning a profile that I haven't dived a few dozen times before, I like to do a sanity check on my RDP. It's possible to plan a multilevel profile on a PADI table (no, I'm not saying how, but it's been researched and published. The paper is out there on the web), and I've checked quite a few of those estimates against Suunto's Dive Planner software. There's quite a good match. If anything, the Suunto software is the most liberal.

Of course, while diving I check my DC's display for remaining bottom time quite frequently, and I normally do what my DC tells me to. But the planning helps me to know what I'll tell the dive leader/boat tender when they ask about my max run time and my max depth (which is a requirement on every club dive).



--
Sent from my Android phone
Typos are a feature, not a bug

 

[RJP]

Actually, I thought I was projecting the OP's documented behavior.



Right. Pick on my published credentials instead of identifying what part of my speculation you think is actually incorrect. Are you asserting that I am wrong and that there are PADI instructors who teach only tables and teach their students to not use dive computers? That is the assertion that I made, that you quoted.

RJP, you post a lot of really great stuff. I really respect and value the professional, analytical, and extremely educated and intelligent basis that is part of your normal postings. I am surprised that you would turn to a personal attack instead of responding to the assertions I made or the speculation I attached to them.

Wasn't a personal attack, simply pointing out that you have no credible basis to make many of the assertions and speculation that you put out there. You'd have the same right to call BS on me if I started opining about "the reality" of training for extended-range cave penetration, hypoxic TMx, HPNS, and isobaric counter-diffusion. I've taken courses from a dozen instructors across across a half-dozen recreational and technical agencies and five or six different shops or dive ops around the US and outside the US. I've DM'd classes with another half-dozen or so instructors over the course of 7-8 years, probably with more total OW students than many instructors have ever taught. On the boat I've seen hundreds of people planning fun dives and dives as part of courses. Even with all that... my experience is so minimal compared to others that I don't pretend to know what "the reality is" when it comes to teaching.

What I can tell you is that the shop where I trained currently teaches with the ERDPmL which is essentially "tables" built into a calculator. I've also seen several OW courses at the dive OP I frequent in Curacao and all the students were diligently working out dive plans on blue and white plastic cards. So yes, I can tell you with 100% certainty that there are PADI instructors who teach tables and don't teach computers in the OW setting. I've never seen anyone teach students "to not use dive computers" whatever that means.

PS - I'll save you some keystrokse: yes, a backup computer would possibly have obviated the OP's issue. (That assumes that if he had one he would chosen not ignore that one too.)

 

[TSandM]

I think the point people are trying to make is that the OP could have had tools to help him decide what he could or should do for the second dive. He could have followed the training of computer-only trained people, and not done another dive after bending his computer. He could have converted his dive to tables, used surface interval information, and planned a second dive that way. He didn't do any of those things, but just decided to follow the DM's decompression information.

Yes, if you don't feel comfortable enough to use the tables, one hopes you wouldn't use them. Yes, you could use them incorrectly -- again, one hopes you might ask someone else on the boat for a sanity check. But even TRYING to use a validated tool is better than using nothing, isn't it? Unless the "using nothing" meant sitting out the second dive, which I agree is probably the easiest course to recommend.

As with so many other situations in diving, if you really want to fix this one, you don't start when the diver has two feet in the incident pit already. You go back to the pre-dive, and check the settings on the computer, so it works properly. Or, having gotten in the water with it improperly set, you decide to follow its output anyway, and shrug off a few minutes of bottom time. Or, if you have a set of independent tools (whether that is a spare computer, ratio deco, or tables) you decide to follow those. But you don't just shrug off your deco status and do a second dive based on someone else's computer. That is assuming an unknown degree of increased risk, and I don't know about anybody else, but I have a hard enough time sometimes deciding how big a risk I'm willing to take, even when I have a pretty shrewd idea of what it is.

 

[rhwestfall]

interesting enough, according to The PADI Wheel, if he was 5 min @ 90' (ends as "B"), and had gone up to 60', his first dive was right at the limits as NDL is 45 minutes when "starting" there as a "B".... Also, 60' is the max second depth for ML calculations from 90' initial depth on the Wheel... he blew it by staying below 60'... (along with many other tactical "errors").

Now, the fine print also says, since he blew the NDL by more than 5 minutes (can't really tell because he blew it by being below 60'), a DECO stop of 15 minutes at 15' (or until you are out of air) is mandatory, along with staying out of the water for 24 hours.....

(and, for the record, I have never taken a PADI course)

 

[RJP]

That is assuming an unknown degree of increased risk, and I don't know about anybody else, but I have a hard enough time sometimes deciding how big a risk I'm willing to take, even when I have a pretty shrewd idea of what it is.

I skipped the last offered dive on my recent trip to Truk. Was the Rio de Janeiro Maru. One of my favorites. My computer said it would be no problem. V-Planner said it would be no problem. I'm sure I could have run the repetitive dive series on plastic tables or the ERPDmL and found it to be OK. Some voice in the back of my head said after 8 days of relatively pedestrian deco diving "You know what... skip it."

I figured there's no reason that the axiom saying "anyone can call any dive, at any time, for any reason" shouldn't apply to the voices in my head, too.