But the Wheel and eRDP-ML are only useful AFTER the dive. It is very unlikely you will have an exact profile before the dive. I suppose you could use the Wheel under water but it's out of the question for me unless I can bring my reading glasses.
I liked the square profile approach of writing ANDLs on a slate. It was simple and I understood it. None of the other schemes seem to do much before the dive and after the dive they can only tell you whether you need to head for a chamber.
I'm a strong supporter of tables and square profiles. For boat dives it works pretty well. But for multi-level diving and the increased down time it delivers, I don't see a way around using a computer.
Richard
The dives where multi level planning is most useful are dives like wall dives where you can indeed pre-plan the profile and then dive the actual planned profile very closely. In most sites, if you know the site or get a decent briefing, you can pre-plan the levels fairly accurately.
The important point is the increased planning ability that is allowed, even if you end up diving the computer anyway.
For example, on a no deco multi level dive, I can to dive at 130 ft for 10 minutes, then come up to 70 feet for 15 minutes, then come up to 40 feet for 30 minutes and still be within the NDL at 130, and 70 ft and be well within it at 40 ft.
But actually diving that profile would require 98 cu ft of gas assuming a SAC of .6 and 114 cu ft assuming a SAC of .7.
Consequently, if you pre-plan the multilevel dive with a Wheel, tables, etc, you know what is possible in terms of depths, dive times and NDLs. You can then do some preliminary gas planning to see if it is practical from a gas plan perspective, and if not, re-adjust the dive plan to better match the gas you have available as well as the gas reserves you require.
I contrast, if you just ride your computer, it will monitor your deco status and show you the increase in bottom time as you ascend to shallower depths, but you will just be riding the SPG as well and reacting rather than really knowing how the dive will progress.
For example, now that I know the dive plan in terms of depths, times and NDLs as well as the gas required, I know what to expect and I can anticipate how much gas I will have left at any point. If I am breathing more gas than planned, it will become obvious early in the dive, as will any SPG failure where I may get an innaccurate / misleading reading (stuck needle, etc). Similarly, if the computer fails, I don't need to abort, I can stay on the plan and finish the dive in a normal manner.
Actually planning the dive takes a bit more effort - about 5 minutes more in this case - but I can then dive with a much higher level fo knowledge and a much higher degree of confidence with no surprises and less potential for an "oh ****" moment, so it is 5 minutes well spent.