DiveGolfSki:
.... but we're talking basics here (he said NDL dives). Say you're in Truk after having spent 24 hours on the plane, making your first dive ... a casual 80 ft dive, you splash, your computer malfunctions (for whatever reason) at 30 ft, you still have a watch and depth gauage functioning. Do you abort the dive?
My point is ... whenever possible diving tables is good backup. Clearly in your case (a multi-level dives) it's not.
Many times divers post "I always keep track of my dives on tables". That tells me that most likely they are either new divers doing very short dives; or that they are diving sites (or wrecks) that result in fairly close to square profiles
I'm talking NDL dives too. Nothing wild or fancy.... just jumping off a boat with a single AL80 and tooling around a reef. Of course, when starting the first dive, you have are starting clean and you can just do a square profile plan as backup --- 80', 30 minutes, or some multilevel profile that you remember. (I do indeed have a handful of multilevel profiles handy in memory, just because they are my dive plan so often -- so my backup for the Truk situation you hypothesize would be much better than just 80' 30 minutes).
A common profile in Maui is 80' or 120' max, with dive time of an hour or so. Obviously way off any square profile table, even though the dives are within NDL and are very conservative profiles. A lot of dive sites have interesting stuff at all depths, so it's easy to do a multilevel dive with max depth >80' and total dive time on an AL80 of 60+ minutes using just a single AL80. In those cases, it's difficult to do as you suggest and keep track on the tables. This is where a computer comes in very handy.
In other areas, with close to flat bottoms and nothing of interesting between the bottom and the surface, then YES, keeping track of everying on tables is easy.
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So when you post "if the computer "craps out" at the beginning of the dive, the dive is not over for me since my backup (my dive plan, tables and brain) tells me otherwise." my question is whether
1) he's really just referring to the first dive of the day, where there hasn't been anything to track.
2) he's diving square profiles, which means that you don't lose much bottom time when using tables
3) he's actually going to the trouble of planning and tracking multiple level profiles with the PADI wheel
4) his plan is really nothing more that having looked at his computer before starting a 2nd or 3rd dive and remembering the NDLs that his computer has generated before the dive
OR
5) he's got some other improved method not mentioned above.
I'm always open to learning new tricks, so please tell us some more about how you keep track on repetitive dives.
