"Riding your Computer Up" vs. "Lite Deco"

[redacted]

Diver A does a dive on air. He goes to 120'. His very aggressive recreational computer gives him 15 minutes of NDL (matching the NOAA table for Air). He stays until the computer NDL counts down to 0 then does a normal ascent and stops at 15'. He decides to be extra conservative and stops for 5 minutes and gets out.

Diver B does a dive on air. He goes to 120'. He has the same computer as Diver A. He also stays for 15 minutes, whereupon he adjusts his computer and sets it for a higher level of conservatism. He does a normal ascent and his computer tells him to stop for 4:00 at 40', 2:00 at 30', and 9:00 at 20', which he does - knowing all the while that if he has to, he CAN go directly to the surface.

That's the difference between using GF100/100, having no mandatory deco, and "making it up" versus using GF30/70 and letting the computer figure it out for you.

And you are advocating that Recreational divers should operate like Diver A.

I often feel like I'm just showing my inexperience, and I've said this many times before, but my personal feeling is that I would always rather have a computer calculate my ascent for me than to "make it up" in my head. In this example - which, by the way, is an example of EXACTLY what this thread is about - it seems to me that Diver B is diving more safely than Diver A.

OTOH, neither diver will have exceeded what is considered minimal acceptable risk of a DCS incident but I expect A will have a slight advantage in his gas loading status at exit. But, it they both splash for a subsequent dive at the same time, I expected the advantage will be with diver B. Very small differences in both cases.

 

[Lorenzoid]

Mayby, if MOST books that you read are instructional material published by a scuba training agency. I don't think I have ever seen such a statement in any other technical documentation.

What is "technical documentation"? You mean blogs you found on the Internet? I admit I can't cite numerous books that I know include such a disclaimer. Off the top of my head, I'll say Steve Lewis' The Six Skills and Other Discussions has such a disclaimer in the inside cover to the effect that the book is no substitute for actual training. @Doppler apparently doesn't think it's wise for you to attempt to learn technical diving from reading his book. I am willing to bet any of the other legends of tech diving believe similarly.

 

[lowviz]

Huh? Those divers are ending dives because they're low on air, not because they're running out of NDL. They are not the ones pushing for more aggressive computers, I don't think.

 

[lowviz]

Dick Rutkowski is alive and well. ...//...

Thanks for that background, very interesting.

But I was referring to OUR VooDooGasMan: Bounce Dive

 

[kelemvor]

Mayby, if MOST books that you read are instructional material published by a scuba training agency. I don't think I have ever seen such a statement in any other technical documentation.

I think you're right. The diving books I own that weren't sold by NAUI include no such disclaimer.

 

[scubadada]

Thanks for that background, very interesting.

But I was referring to OUR VooDooGasMan: Bounce Dive

Sorry, I'm an old guy, I think Dick was the original. I was diving well before I started playing on SB

 

[redacted]

What is "technical documentation"? You mean blogs you found on the Internet? I admit I can't cite numerous books that I know include such a disclaimer. Off the top of my head, I'll say Steve Lewis' The Six Skills and Other Discussions has such a disclaimer in the inside cover to the effect that the book is no substitute for actual training. @Doppler apparently doesn't think it's wise for you to attempt to learn technical diving from reading his book. I am willing to bet any of the other legends of tech diving believe similarly.

While I found such a disclaimer inside PADI's rescue diver book, I did not find that disclaimer in Steve's book.

Technical documentation like math, science, and engineering books. The kinds of books onee might use to enhance knowledge necessary for the design and development of combat systems for the military.

Obviously, many other possible examples including scuba regulator repair manuals.

EDIT: I just found my PADI EAN manual and it clearly has that disclaimer which tells me either they know their manual is lacking or they are just trying to sell classes. Most scuba training results in the acquisition of knowledge and skills. Knowledge can be obtained without classes. Books (training materials) and exams are all that is really needed. Skills are a different case as they usually require actual practiice and feedback to achieve a standard which can not be satisfied with a book. But there are still options for developing skills that do not involve formal paid instruction.

 

[boulderjohn]

Voodogasman was a frequent poster on ScubaBoard who advocated vigorously for divers to dive to depths below 200 feet on single AL 80s with no redundancy and no training, arguing that it was no big deal and loads of fun. Yes, he was serious. He argued for other non-mainstream practices as well. Because ScubaBoard's Terms of Service forbid the advocacy of unsafe diving practices, he frequently had trouble with moderators and had many of his more extreme posts deleted. After many conflicts, he was no longer part of the community. I could look it up, but I will just say that it is my belief that he was eventually banned. It might have been a temporary ban that required hims to request reinstatement. When that happens, they rarely come back and make that request. It may have been a permanent ban. Or he may have just decided to stop posting.

 

[scubadada]

Voodogasman was a frequent poster on ScubaBoard who advocated vigorously for divers to dive to depths below 200 feet on single AL 80s with no redundancy and no training, arguing that it was no big deal and loads of fun. Yes, he was serious. He argued for other non-mainstream practices as well. Because ScubaBoard's Terms of Service forbid the advocacy of unsafe diving practices, he frequently had trouble with moderators and had many of his more extreme posts deleted. After many conflicts, he was no longer part of the community. I could look it up, but I will just say that it is my belief that he was eventually banned. It might have been a temporary ban that required hims to request reinstatement. When that happens, they rarely come back and make that request. It may have been a permanent ban. Or he may have just decided to stop posting.

Thanks @boulderjohn interesting history of SB. I would imagine this is the background for many of the deep air comments

 

[w3dge]

But, I would rather have the computer tell me that than take the risk of "making it up" when my chosen GF would have actually dictated more deco.

If you have chosen GFs, why not just dive to them? Choose the amount of deco time you're willing to do (15 minutes in your example) and dive to that plan.

Why have a computer tell you that you're within NDL if you don't believe it? I know you're going to say that it means you can head straight to the surface anyway if you need to; but given that heading straight to the surface should be your LAST resort regardless, if you NEED to head to the surface, you need to head to the surface - regardless of the numbers on your wrist.