The U.S. Navy no-decompression dive tables have one thing going for them -- they are easy to remember when your computer floods at depth
Do keep in mind that the agencies (SSI, PADI, etc) have more conservative tables
for your safety. But running a square profile before your dive is uncomplicated, especially for a first dive. Then stick to the conservative time/depth, jump in with your computer, and enjoy a relaxing journey and a safe surface interval. Remember, it's supposed to be fun, so don't skate near the no-deco edges.
http://www.coralspringsscuba.com/miscellaneous/usn_manual.htm
Specifically, the dive tables are in chapter nine, pg 54 of 70.
http://www.coralspringsscuba.com/usn/Chap09.pdf
Here's the short version:
The Money Rule to get a range of no-deco times/depths. Use quarters, a fifty-cent piece, dollar bills and a $5.
25 ft @ 500 min, 50 ft @ 100 min, 100 ft @ 25 min
The tables say you can stay at 25 ft for 595 minutes, but they don't make $6 bills in the U.S., and after eight hours (480 minutes) I'd have more pressing needs!
The 120 Rule for the middle depths -- add the maximum depth and time to get 120.
60 ft @ 60 min, 70 ft @ 50 min, 80 ft @ 40 min, 90 ft @ 30 min
The Plus-100 Rule for the shallow depths -- note we have three new numbers between 25 ft and 50 ft, and how well the pattern fits.
50 ft @ 100 min, 40 ft @ 200 min, 35 ft @ 300 min, 30 ft @ 400 min, 25 ft @ 500 min
The Minus-5 Rule for the extreme recreational diving depths -- think about air management and the "oh, sh**!" factor in getting back to the 15-foot safety stop on time. Again, three new depths added in a pattern to 5 ATM (132 ft.)
90 ft @ 30 min, 100 ft @ 25 min, 110 ft @ 20 min, 120 ft @ 15 min, 130 ft @ 10 min
Do note how these numbers compare to the dive tables used by your agency and plan accordingly. Divers still get bent using tables and computers! Be conservative, and enjoy your new adventures.
