I'm interested in learning how to calculate nitrogen absorbtion, no decompression limits and multi-level dives by hand. Where can I find the equations/tables of absorbtion rates of tissues/whatever this actualy takes? I've got a vague idea of the theory and I've taken integral calculus so I think I can handle the math, but google hasn't been any help on this one.

Buy Basic Decompression, Theory and Application by Bruce R. Wienke. You will find plenty of math with some overview of the various theories that have been around. You can look at www.bestpub.com to order.

I don't remember exactly where I found it, but I downloaded a PDF of Bruce's Decompression Theory. It's 182 pages and full of all the math and tables that you could possibly want. I believe the link came from this board (and may have been posted by Bruce himself). -Rob

visit http://www.lizardland.co.uk/DIYDeco.html Then get the Buhlmann tables. Buhlmann is not that hard. For VPM stuff, see http://www.decompression.org/maiken/VPM/VPM_Publications.htm

Definitely get a PADI wheel. You can easily teach it to yourself and do all of the calculations that you mentioned. It's portable and waterproof too.

yeah, I want to know how its calculated, and I'm planning on getting a dive computer rather before a wheel and would like to have a better understanding of how they work. What I'm hoping to do here is program my TI-89 to do what the padi wheel does, but out of the water obviously. I might start out writing a web based version since I program mostly in perl though so I can figure the algorithms out, and because ti basic is a pain in the neck.

If you still have questions after reading all of this, you're going to become famous. Bruce R. Weinke: Modern Decompression Algorithms: Models, Comparisons, and Statistics Reduced Gradient Bubble Model in Depth Basic Decompression Theory and Application Basic Diving Physics and Application Technical Diving in Depth Johnny E. Brian, Jr.: Gas Exchange, Partial Pressure Gradients, and the Oxygen Window Erik C. Baker: Clearing up the Confusion About Deep Stops Understanding M-values

Padi now has their new eRDP, an electronic dive planner. I learned on the tables, not the wheel, but to my understanding multilevel dives are easy to make on the table, just calculate your SI as 0 minutes and calculate as you would a multiple dive using the RAT. The RDP is a NDL table, so you get both in one setup, you should have learned the basics of how to use it in OW, you can always go back to your instructor and learn again if you forgot. The programming however, I have no clue.

On some dive profiles this will cause you to exceed NDL during the dive, and perhaps would cause you to surface while still having a decompression obligation per the DSAT/PADI model. While the pressure groups and the single level NDLs of the PADI wheel are the same as for the PADI RDP table, the wheel has additional reduced NDL limits for multilevel dives, and also restrictions on allowable combinations of multilevel depths. Even though this 0 SI method can cause you to violate the PADI/DSAT model a bit, it is still a reasonable way to do some rough planning. Just remember that a dive to the limits using this method are actually a bit beyond the limits of PADI/DSAT model.