Do you think computers encourage risky diving in new/ young divers?

[johndiver999]

The answer I’m looking for is “depth gauge”. A watch is worthless for diving (except to tell you what time of day it is) without some sort of depth gauge.
If your computer craps out you better have some way of determining your depth. I would rather have a depth gauge than a watch if given the choice of one or the other if my computer craps out. If your computer dies the dive is over and it’s time to come up, no exceptions. You can always use your smallest bubbles as a way to time your ascent and you can always count one-one thousand or sing your favorite song to gauge a rough three minute stop, but if you have no way of determining depth besides your dead computer you’re screwed.

I think if you are watching your computer and you are below the Deco limit, then if/when the computer fails, you just need to come up at a reasonably slow rate, possibly using bubbles and or particles in the water to judge your ascent rate. When you get to a shallow depth, you can deploy an SMB on a string which may have a known length or possibly a knot or two in the string on a spool/reel. The diver can also estimate their safety stop depth from visually looking at surface if the visibility is decent. The actual depth of a safety stop is not critical anyway, something between 30 and 9 feet will probably work quite well. I don't see that controlling the ascent rate nor the safety stop depth as a big worry.

All this is predicated on a computer failure AND a loss of all buddies. Obviously you could refer to a buddy's computer to make a controlled ascent. Overall, I don't think a redundant depth Gage is necessary and I never use one myself.

 

[TMHeimer]

The answer I’m looking for is “depth gauge”. A watch is worthless for diving (except to tell you what time of day it is) without some sort of depth gauge.
If your computer craps out you better have some way of determining your depth. I would rather have a depth gauge than a watch if given the choice of one or the other if my computer craps out. If your computer dies the dive is over and it’s time to come up, no exceptions. You can always use your smallest bubbles as a way to time your ascent and you can always count one-one thousand or sing your favorite song to gauge a rough three minute stop, but if you have no way of determining depth besides your dead computer you’re screwed.

Sorry my bad. I just assumed anyone in his right mind diving tables and watch obviously has a depth gauge. Otherwise the other 2 are virtually pointless.

 

[Eric Sedletzky]

You said, "If your computer dies the dive is over and it’s time to come up, no exceptions." Good advice for a novice diver. If you're more experienced why end a perfectly good dive? Just go shallower to say 30 or 25 ft and finish the dive assuming your SPG is working. You don't need to worry about NDL. You can estimate the depth and you can estimate 3 minutes for that non-mandatory safety stop.

Because this is SB and many novice divers come here to lurk and glean information. It is a blanket rule in virtually all recreational standards that when your dive computer craps out you come up. The only exception I can think of is if you had an identical back up computer and you continued without skipping a beat, but then there would be no back up to your back up. Safety first right? Safe safe safe, make sure everyone is always safe.

 

[wetb4igetinthewater]

You said, "If your computer dies the dive is over and it’s time to come up, no exceptions." Good advice for a novice diver. If you're more experienced why end a perfectly good dive? Just go shallower to say 30 or 25 ft and finish the dive assuming your SPG is working. You don't need to worry about NDL. You can estimate the depth and you can estimate 3 minutes for that non-mandatory safety stop.

I'd never give that advice to anyone, novice or not. While I dive with 2 Shearwaters, I have that backup. But I'd never try to estimate time and my remaining NDL. No way. While I respect your expertise in decompression theory/algorithms, that is some serious normalization of deviance.

 

[EFX]

Many people on SB insist we should understand what our decompression programs are doing and not just follow our PDC's with blind faith. Well OK, I know that following a deep dive with low remaining NDL, say under 5 minutes, that ascending to a shallow depth of 25 ft or less the NDL goes up exponentially to a higher value. You do not need to estimate your NDL. Here is an example:

A 100 ft dive for 16 minutes using DSAT tables with a descent/ascent speed of 60/30 fpm, on air, with a GF of 95/95 will give you 1 minute of NDL. Now your PDC craps out. What do you do? You ascend to 25 ft arriving there with 17 minutes of NDL. After 30 minutes at 25 ft your NDL goes up to 969 minutes. You ascend to 15 ft for 3 minutes and surface with a GF of 36. So, what's the problem?

 

[Blackcrusader]

You said, "If your computer dies the dive is over and it’s time to come up, no exceptions." Good advice for a novice diver. If you're more experienced why end a perfectly good dive? Just go shallower to say 30 or 25 ft and finish the dive assuming your SPG is working. You don't need to worry about NDL. You can estimate the depth and you can estimate 3 minutes for that non-mandatory safety stop.

If I was deeper than 15m I and my computer died I do have digital console with Time Depth etc... I would probably just complete my dive at 10m or less as you would not exceed NDL limits even for an hour at shallower depths. My console spg gives also gives me time range to 50 bar from whatever depth and time through the dive.

 

[Eric Sedletzky]

Many people on SB insist we should understand what our decompression programs are doing and not just follow our PDC's with blind faith. Well OK, I know that following a deep dive with low remaining NDL, say under 5 minutes, that ascending to a shallow depth of 25 ft or less the NDL goes up exponentially to a higher value. You do not need to estimate your NDL. Here is an example:

A 100 ft dive for 16 minutes using DSAT tables with a descent/ascent speed of 60/30 fpm, on air, with a GF of 95/95 will give you 1 minute of NDL. Now your PDC craps out. What do you do? You ascend to 25 ft arriving there with 17 minutes of NDL. After 30 minutes at 25 ft your NDL goes up to 969 minutes. You ascend to 15 ft for 3 minutes and surface with a GF of 36. So, what's the problem?

You’re giving some people here heartburn just mentioning “air” and “diving” in the same sentence, lol!

100’ on air? Oh god you’re so gonna die! Lol!!!

 

[Dark Wolf]

You’re giving some people here heartburn just mentioning “air” and “diving” in the same sentence, lol!

100’ on air? Oh god you’re so gonna die! Lol!!!

DW

 

[TMHeimer]

Or, you could ascend to 15' and stay as long as your air lasts--safety stop anyway, working computer or not. That only makes sense on shore diving of course.

 

[johndiver999]

I'd never give that advice to anyone, novice or not. While I dive with 2 Shearwaters, I have that backup. But I'd never try to estimate time and my remaining NDL. No way. While I respect your expertise in decompression theory/algorithms, that is some serious normalization of deviance.

Seriously? I would not recommend that to a novice, but I certainly wouldn't have any problem doing it myself.