My aforementioned reference to "laziness," wasn't wholly reliance on computers -- but stems from an increasing inability to actually use physical tables and do the maths . . .
Necessity of a back up computer/watch for NDL diving
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My aforementioned reference to "laziness," wasn't wholly reliance on computers -- but stems from an increasing inability to actually use physical tables and do the maths . . .
I have one hose mounted AI (suunto Cobra) ond one wrist monted AI.
I have had a failure once, and could continue to dive on my backup till my wristmounted was fixed a few days later.
I have had a failure once, and could continue to dive on my backup till my wristmounted was fixed a few days later.
:shrug: If you want to keep playing: the problem, as posited, was 4 days of 4 dives to NDL each day. My brain would need 6 hours and one second of good night sleep; then, on the morning of day 5 it will be able to determine my accumulated gas loading according to a decompression model developed for recreational multi-day diving. You may call me RainMan if you wish.
Diver-Drex
Contributor
For recreational diving I always have a watch, depth gauge and tables as backup. Computers don’t fail often and a battery change is likely the fix. But for all of their shortcomings, tables have some advantages for multi day diving. Here are three scenarios to illustrate this.
1. Single computer with a watch, depth gauge and tables - Your computer dies so you call the dive. For your next dive you go back through the dives in the series (hopefully you log dives and not just count on the computer) and determine your NDL for you next dive. Your next and all subsequent dives are done using tables.
2. Two computers - Your primary fails so you complete the dive using your backup. For your next dive you have only one computer. So you’re back to a watch, depth gauge and tables as your backup.
3. Three or more computers - Your primary fails and you complete the dive on your backup. On the boat you reach for your third computer. But because it has no data from the previous dives it is essentially a bottom timer. So again, you are back to tables.
Tables have limitations and computer failures are rare. But I would never be without tables. I dove for almost 30 years on tables, computers are not nesessary for recreational diving and tables may be a much better backup than most people realize.
1. Single computer with a watch, depth gauge and tables - Your computer dies so you call the dive. For your next dive you go back through the dives in the series (hopefully you log dives and not just count on the computer) and determine your NDL for you next dive. Your next and all subsequent dives are done using tables.
2. Two computers - Your primary fails so you complete the dive using your backup. For your next dive you have only one computer. So you’re back to a watch, depth gauge and tables as your backup.
3. Three or more computers - Your primary fails and you complete the dive on your backup. On the boat you reach for your third computer. But because it has no data from the previous dives it is essentially a bottom timer. So again, you are back to tables.
Tables have limitations and computer failures are rare. But I would never be without tables. I dove for almost 30 years on tables, computers are not nesessary for recreational diving and tables may be a much better backup than most people realize.
All very true -- much like the old bromide about there being two types of motorcyclists: those who have been down and those who are going down . . .
As an aside, I have known four people who have contracted DCS over the years -- all of whom slavishly followed the NDL limits of their computers; and have yet to meet one who suffered injury by responsibly using the rather conservative recreational tables. I'm all for accuracy; good modeling; but I also want to see it on paper . . .
caruso
Banned
Diver-Drex
Contributor
I dive two computers for technical dives and I wouldn’t do otherwise. So I think it’s a significant stretch to say that computers bend divers. And I’m not saying you are saying that. I think it’s more about diver behavior. I learned how to plan dives and follow those plans. You had to, well, pay attention. Maybe it’s generational, maybe blind reliance on technology,... but many, many divers just dive until the computers tell them to stop. Why not, people drive that way too?
You're correct. It's simply a blind reliance on electronics, and indiscriminately pushing the NDL. Regardless of the device, it's always on the diver -- his or her responsibility. I have just found, over the years, that far too much faith has been placed in the admittedly convenient devices; and that more chances are often taken than in days when we planned dives on paper . . .
Electronics and technology in general has come a VERY long way since "years ago". I have a computer from 1990 that has never failed, flooded, or otherwise fallen short of doing what it was designed to do. I stopped carrying it in 2017 because I didn't need it anymore. I have seen electronics go Tango Uniform many times. I work with communications equipment everyday. It fails. Rarely, do two pieces of gear fail at the same time. I have redundant comm gear. I also have a backup computer as well as spares. I know, I know. A spare isn't any good until you have let your tissues clear. Then it can be a primary or backup, but by diving with two computers in the first place, I have a record of what the computer thinks my tissue loading is. And honestly, the people who programmed my dive computer have studied gases in the body a whole lot more than I have. They do what they're good at and so do I.
Cheers -
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