Computer dies, why can’t I continue to dive on tables?

[dumpsterDiver]

I don’t recall this being discussed in previous threads. I have had my dive computer die (or more commonly I forget to set the oxygen level and it reverts to 50% during a dive past 70 feet and locks me out for 24 hours).

I do NOT carry a redundant computer and I am not going to forgo diving for the next day. What I normally do is remove the battery and reboot the computer and start “fresh” and continue to dive for the remainder of the day. I make accommodations for the repetitive dive(s) by punching in a much lower nitrox mix and taking long surface intervals, longer safety stops and not going into deco on the computer, plus I use common sense on what I know are reasonable dive times. I know this is a dangerous practice and IS NOT RECOMMENDED by any agency, I’m sure.

I have been wondering if the following would be a safer and more reasonable approach to the situation:

Lets say you get down on a dive and find that your computer is going wacko. You know you are not in deco and you immediately ascend and do a normal (and maybe an extra) safety stop(s).

Now you break out the dive tables and assume that this dive was to the maximum no-deco limit for the maximum depth that you attained. (If you were not doing a square profile, maybe you should choose a more representative depth to represent your last dive). Then you use the dive tables and figure that the dive you just completed was to the no-deco limit for that depth. Now you plan the remainder of the day’s dives under this assumption and simply follow the tables. I would also take a peak at what my buddy’s computer says about subsequent dives and also not push the no-deco limits on the tables.

I know that this is not going to ever be a recommended practice, but it seems like a reasonable procedure to follow, Is it better than re-booting the computer and totally winging it, like I do now?

 

[Cave Diver]

Now you break out the dive tables and assume that this dive was to the maximum no-deco limit for the maximum depth that you attained. (If you were not doing a square profile, maybe you should choose a more representative depth to represent your last dive). Then you use the dive tables and figure that the dive you just completed was to the no-deco limit for that depth. Now you plan the remainder of the day’s dives under this assumption and simply follow the tables. I would also take a peak at what my buddy’s computer says about subsequent dives and also not push the no-deco limits on the tables.

I know that this is not going to ever be a recommended practice, but it seems like a reasonable procedure to follow, Is it better than re-booting the computer and totally winging it, like I do now?

I just addressed a similar question in a recent post, I'll see if I can find it instead of retyping.

Edit, found it:

Depth gauge/computer:
Fails: Begin slow ascent. Diving within recreational NDL's there is no decompression obligation. Use watch to make 3 minute safety stop.

If you are checking your gauges on a regular basis you should already know your max depth for the dive. You can use the time from your watch + max depth to plan your dive using tables. You can continue diving on tables for the rest of the trip if necessary.

Alternatively, if you're paying close enough attention to figure average depth you could use that with tables, but for most recreational divers I would recommend they stick with max depth for figuring repetitive dives.

I think the reboot the computer and wing it is a very bad idea and that you're playing Russian Roulette with your NDL's that way.

 

[Scott L]

Luckily, I have been diving since 1983 without a computer failure. I do have IANTD's nitrox tables in my dive backpack with me at all times but unless it was a spectacular day I would most probaly sit out the rest of the outing since I live here and dive frequently...

 

[dumpsterDiver]

Luckily, I have been diving since 1983 without a computer failure. I do have IANTD's nitrox tables in my dive backpack with me at all times but unless it was a spectacular day I would most probaly sit out the rest of the outing since I live here and dive frequently...

Yeah but you probably know how to use your computer and replace the batteries when they need it..

 

[Scott L]

Yeah but you probably know how to use your computer and replace the batteries when they need it..

Well maybe, but I never heard of your trick so we are even...

I do NOT carry a redundant computer and I am not going to forgo diving for the next day. What I normally do is remove the battery and reboot the computer and start “fresh” and continue to dive for the remainder of the day.

 

[Rhone Man]

Related thought: I have heard that if you dive on a liveaboard, if your computer fails, often they simply make you sit out for 24 hours before continuing on tables.

I can imagine situations where that would come a disappointment.

 

[Scott L]

Related thought: I have heard that if you dive on a liveaboard, if your computer fails, often they simply make you sit out for 24 hours before continuing on tables.

I can imagine situations where that would come a disappointment.

How would they know unless someone told them. Do they frequently monitor?

 

[Bubbletrubble]

The method you describe for subsequent dives deals with NDLs but ignores cumulative OTUs. I'm going to assume that you'll probably take it easy and stay conservative with your oxygen exposure for at least the next 24 hrs.

With your table method, how do you account for nitrogen loading from previous dives (prior to the dive during which the computer failed)? The possibility exists that the dive computer will not fail on the first dive of a repetitive dive series, right?

 

[redacted]

At that point, rerunning your dives on tables and continuing your diving on tables should be no problem unless you have managed to go off the tables on your computer dives. That is, when you rerun you computer no-deco dives on tables and find they involved one of more deco dives. Then you are venturing into the unknown.

When I dive the Flower Gardens, that would be the problem when trying to go from a failed computer to tables. The school solution is a 24 hr SI and you are good to go. I don't plan on doing that should I experience a computer failure. My plan is to to put myself in a Z pressure group and finish the day's diving on tables while switching to my backup computer (from my save-a-dive kit) and then continue on the computer the next day. I know no agencies endorse such a recourse because it is in the realm of the unknown. PADI's Z pressure group may have lower residual loading then my Oceanic computer even when I was within NDL. But that is my solution.

 

[Cave Diver]

Related thought: I have heard that if you dive on a liveaboard, if your computer fails, often they simply make you sit out for 24 hours before continuing on tables.

I can imagine situations where that would come a disappointment.

If you're logging the dives each night, you should be able to go back and run a profile on tables to get an idea of your NDL loading. Of course this is another good argument for learning depth averaging and keeping constant track of your depth/time and diving tables vs. computers. Or make sure that you're diving with a backup computer.