Posted by Walt on February 14, 2005 at 13:21:53:
In Reply to: Re: Uwatec Aladin v. Suunto Cobra posted by Elaine on February 14, 2005 at 10:12:14:
Background: I use a Cobra and have used a Dive_Rite Duo (my wife's) She also uses a Veo 100 and I dive with a friend who has a Uwatec.
I like the Dive-Rite the best as it provides a little more flexibility in setting preferences for ascent rate (15 or 30).
My Cobra locked out once as I shortened a deco stop (an honest penalty, shame on me) only problem was that it stayed locked out for a whole week - hit the water within 48 hours and it relocks. You can do the battery removel, but that's cheating and the battery is not really easy to user service. The Duo is definitely user-serviceable.
Our Dive-rite and Cobra provide virtualy identical profiles for depth, time etc., though the Cobra seems to be more conservative for total allowed bottom time during the dive, as I'm the one who usually gets close to the red a little faster during multiple dives. The Veo tends to be a little liberal, but its our back-up if one of our primaries fails. Its attractiveness is its price.
The Uwatec of my friend's seems to be more conservative in terms of required time at different depths for safety stops. We did an identical deep dive (100 ' max.) and he had to stay at 30 feet to deco while my Cobra and my wife's Duo allowed us to go to the normal 20 foot 3 minute stop (we were wondering why he was at 30 feet for so long!)
The moral is that if you have 10 computers, you'll get 10 slightly different answers. And they are all based on theoretical tissue loading models, primarily the USNavy dive tables. However, the USN tables are single depth so each computert takes a little liberty with how to do teh calculations for multio-level diving.
Frankly I don't press the limits, if I'm near yellow, I start my ascent, do a 1 minute at half max. depth and 5 minutes at 15 to 20 feet and tryu to never ascend faster than my smallest bubble (about 30 feet a minute; ideally 15 if I have the time).