Easy Guide to Deco Computers

Recreational or Deco? Recreational limits say stay within no decompression time limit (NDL) You can go straight back to the surface unless you’re within 3 pressure groups of the NDL (grey areas of RDP) or below 30m The safety stop is just that! 24m dive on Air NDL = 29 mins 24m dive on EANx32 NDL = 50 mins

24m dive NDL = 29 mins

24m dive NDL = 50 mins

What happens if I stay beyond NDL? You NEED to do COMPULSORY stops You can no longer go straight to the surface You have nitrogen bubble build up You need to monitor OTU’s You NEED a DECO plan You need to know what depths to stop at and for how long You NEED to know what those flashy computers actually mean YOU NEED ENOUGH GAS

What happens to dive computers when my NDL is exceeded? Vyper Vyper AIR HelO2

RECREATIONAL AIR DIVE with deco 40 mins @ 24m followed by 11 mins @13m, then 3m until clear to surface RECREATIONAL AIR DIVE with deco 4 mins left for NO DECO 15L twinset

NO DECOMPRESSION DIVE

REACHED NO DECO LIMIT 0 usually flashes Beeps and backlight on

CEILING tells you where you SHOULD be now!!! DECO CEILING tells you where you SHOULD be now!!! to allow deco to count DOWN not UP!! NO DEC TIME changes to ASC TIME Ascent time means minimum time before you can surface Keep an eye on dive time and ASC time!

Some computers place an upward pointing arrow here 3m “ceiling” “floor” 10 mins extra at 24 m causes 10 MORE mins of DECO Not a problem if you’re carrying enough gas!!

Current depth ceiling floor OK so we’ve taken 1 min to go up 11m and lost 1 min deco time Off-gassing

DEEP STOP for 1 minute (optional) 11 mins at this depth but no loss in deco time? Why? Well, you’re still on-gassing at the same time that you’re off-gassing !!

Hourglass symbol appears when you are in the zone Ceiling zone Floor Zone is above the floor and below the ceiling Usual stops can be 12m, 9m, 6m and 3m Means that you are above the ceiling – DESCEND IMMEDIATELY

NOW A NO DECOMPRESSION DIVE AGAIN Some conservative computers add on a normal safety stop at this point This will only stay NDL if you do not go below this 3m floor, otherwise you’re in DECO again!!

NDL not reached yet Max depth Current depth NDL left

Current depth NO DECO TIME left 110 secs STOP Dive time used

Current depth slightly deeper than ceiling 89 mins ASC TIME 48m ceiling .. a deco stop. In 13 secs next ceiling or deco appears 13 secs of DEEPSTOP left In the zone … hourglass

Now do you know yours? Remember.. If you’re going into deco, make sure that you have ample gas Split your main gas into thirds One third in One third out and One third remains for that emergency Deco gas is split in half Half used, half kept in reserve

Deco Disadvantages Its boring Its cold Need lots of gas in reserve Double up on kit in case of failures Its cold!! Its boring!

Deco Advantages You get the Rosalie Moller to yourself