Posted by Steve on March 06, 2001 at 23:48:55:
I've been reading about the DIR recommendation to drop the use of dive computers. It is true that computers aren't necessary yet I for one do use them because I don't want to bother with the dive tables, mostly I do underwater stills and video photography. Taking a quality underwater photograph is difficult enough with working with the marine life, composition and camera settings. It is nice to let the computer do the the deco analysis for me to be free to think about the photography, navigation and air management. All the talk has got me rethinking or at least questioning my methods, especially when it has been mentioned that these computers aren't safe and are more prone to causing DCS then those using tables. I've done four liveaboard weekly trips doing 5-6 dives per day using a US Divers matrix very simple/cheap bar graph green, yellow and red computer. I dive it with blind reliance also, every now and then I check it with the dive tables and every time the tables get busted easily. They can break down as has been said and I'm thinking of adding a backup for this reason.
Two weeks ago I dived San Clemente from the Encore, a very spacious clean large dive boat with a great captain, cook and crew by the way. I've been thinking of upgrading my dive computer to an air integraded one but they are expensive. I borrowed an Aladin Air/X for the trip and also used my Matrix. My four dive profile ended up saw tooth and if I had been using my Naui tables my dive day would have ended after the first dive.
#1. 126' for 31 minutes
My strobe was malfunctioning and the vis wasn't great at the Arch so I studied my computers deco status while my buddy got his shots in. The Matrix was solidly in the yellow and the Alandin said three minutes until deco at 126'. My buddy signaled ascent and as we went up the Alandin said 99 minutes until deco but the Matrix didn't return to the green area until we had done a 3-5 minute stop.
Question for the ones that have weened themselves from computers. Based on the first dive to 126' for 31 minutes how would you plan the next dive after sitting out for 60 minutes? What would be your maximum dive times for a repetitive dive?
steve