MIN DECO
the recreational side of ratio deco
1. A recreational
ascent begins at
50% of average
depth.
Or 50% of maximum depth if leaving the bottom deeper
than the average. Average depth is established by a system
of “depth averaging.” Each five minutes during the dive note
your depth, then remember a culmulative average. So if your
first five minutes averages 60’/18m, then that’s your cumulative depth. If you then go to 80’/24m, then after 10 minutes
your average depth is 70’/21m, and so on. Base your first
stop at 50% of this average depth. If, at the end of the dive,
you are deeper than your culmulative average, then base the
ascent on that deeper depth.
2. the stops are
one minute for
each 10’/3m.
Ascend from depth at a rate of 30’/10m per minute to your
first stop then wait for one minute. If you don’t show seconds on your bottom timer, wait until you see the first minute
change then wait another full minute so you are sure to get
the whole stop. Once your minute is up, ascend at a rate of
30’/10m to the next stop, which is 10’/3m above the first
stop. When the next minute clicks over on your bottom timer,
ascend another 10’/3m for one minute. The travel time is
inclded in each stop, so really you are doing 20 seconds of
travel and 40 seconds of stop.
3. these are the
additional rules
for min deco.
Standard Gasses Apply – Air to 60’/18m, Nitrox 32 to
100’/30m, 25/25 to 130’/39m,
Round shallower to the first stop – a 90’/27m dive stops first
at 40’/12m.
If your surface interval is less than 1-hour, double the shallow stops (2 ATA to surface - 30’, 20’, 10’ / 9m, 6m, 3m).
20’/6m and 10’/3m stops are interchangeable based on environmental conditions. If you can’t hold the 10’/3m stop, do it
all at 20’/6m and then do a slow ascent to the surface.
No ascent is less than 3 minutes, however on a 20’/ 6m dive,
20’/6m becomes your first stop, so you wouild then do two
minutes at 10’/3m then up.