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14-12-2017, 04:26 PM
I personally always used to wear a dive timer that alarmed at 10 mpm and used to accelerate until it went off
EDIT - For the avoidance of doubt - I still do. I am just out of UK deep diving at the moment as I have been on extended maternity leave Working back to it now though.
15-12-2017, 10:58 AM
Just to pick up on one comment.
Ratio deco is nothing like 20/85 or any other GF for that matter.
ratio deco has no set safety margin.
If you do the math for 20 dives at 20 depths with 20 different durations and then map the results against GFs till you get a similar profile, you will find your running 20/80 to 10/125 and most GFs in between
That was the fundamental problem with Ratio deco. It wasn't a deco system. It was a mathematical progression used to mimic a deco system.
You needed to run ratio deco along side GF or VPMB and learn its idiosyncrasies and adapt your RD to suit
I ran RD (my version) against Shearwater GF 30/90 for several years over several hundred dives and as a result I could dive a single deco computer with RD back up and fulley understood where RD needed tweeking to make it work close to my preferred GF
To the best of my knowledge, real time experience and comparison with tables & tweaking was the way RD was taught
I would be 100% confident using RD to mimic 30/90 on a dive of 3 hour duration to 60,70,80M on a CCR with a 1.3 set point.
Out side those parameters I couldn't do it with any degree of certainty
As said before, now I run deco without deep stops I have abandoned RD altogether and now use two dive computers (Shearwater) and a depth and bottom timer (Sunnto).
I think its a bit sad they have abandoned RD.
I am sure with some effort it could be adapted to modern deco theory
Mind you I did think once they went CCR & chose the JJ they would be silly to ignore that extremely competent GF deco computer on their wrists.
Its perfectly understandable that GUE were anti computer in the 90s and early 00s as the tec didn't exist. But over decade later we now have excellent decompression computers which are both flexible and reliable.