Thanks Eqeao. Wow, you are taking "the" course that sets up DECO diving. Eqeao .... That Is Great. My understanding is that these courses have limits to 150ft. So, divers will need yet additional training for the 180ft dept. I am still confused as to creating a dive plan for 180ft. So far, it appears that double tanks, better if 120 steel, filled to 3440 are desirable, and a staged deco bottle, 40%, which gets switched into divers breathing on ascend at 30 feet or so. I am not looking for perfection, just a standard dive or popular dive scenario. Yesterday, I started looking into a 15 minute bottom time at 180 feet, using 8 minutes for descending, and OVER 30 minutes for ascending and decompression. Dah ... what do I know? Very little. I am just trying to get a handle on this "image." I do not mind making mistakes on paper... and having an experienced person correct me. I am all ears.