KimLeece,
This is only the NDL. The whole tables go to 65m (in case of problem at 60 and you had to go lower), but I have several pages of tables and I cannot post them all here.
You can have a look at the whole tables here (warning: in French)
http://www.blueocean.ws/formations/ffessm/table mn90.htm
With the longest time scheduled at 60m (20 mn), the table gives:
20mn at 60 m, 3mn at 9m, 8mn at 6m, 32 mn at 3m, total time for going up 47 mn (add the 20 mn down time), group L. Note that some lower tables give a higher group because allowed down time is a lot higher.
Of course with my 12 l bottle, I could not dive this profile! Air must be planned! And as it is not an RGBM model, I would add intermediate deep stops... that have to be included in the 20 mn of down time if I still use these tables.
To summarise: you are allowed to have a quick look at this deep wreck... not to stay a long time to visit it! And if ever you go lower than 60m, no more dive in the day!
Note that these are designed for people without computer, just timer and gauge (needle gauge: no fast ascent warning -> you control your ascent speed from the bubbles)
but that's what nitrox is for, no?
At these depth, I think that air is safer than nitrox! (and less expensive). But still unsafe due to narcosis, i agree. To dive there (something I will probably never do), i would prefer to learn to use trimix.
Now in our training for level 2, we have learned:
-to use these tables for single dives.
-to use them for successiive dives (surface interval between 15mn and 12 hours)
-to use them for bounce dives (surface interval shorter than 15 mn)... exam exercise was a bounce dive after successive ones... you quickly understand why to avoid bounce dives!
-how to use the tables if you go up lower than requested speeds (which is what you use if you add deeper stops)
-what to do if you have missed or shortened a safety stop, but gone up at proper speed (provided that there is not yet an health emergency which prevents you to stay underwater), how to use the tables in this case
-what to do and how to use the tables if you have gone up too fast (again, with no health emergency)
Do not forget also that we do not dive on coral reefs. Place where you can do interesting really shallow dives are not so numerous, plus we can have huge tides at some places -depth for what you want to see can change quite a lot from morning to afternoon!
Now to dive 3 or 4 tanks in a day... as i only have a 7+5 wet suit, i would be too cold where I usually dive (water 11 C last week, 15 C in summer). If I had to dive on coral reefs in tropical waters, I would by a computer with an algorithm which allows more than 2 dives!