Out of curiosity, do most computers handle going beyond the NDL and dealing with deco, or are those a sort of emergency mode that the computer really shouldn't be in? Are there specific tech computers that are designed for deco?
All the computers that I have seen will go into deco mode and provide a deco profile to terminate the dive.
Thing is that I would not really rely on this for a number of reasons;
- Most people don't know what algorithm their computer is using or how aggressive or conservative it is. Therefore they don't know much about the profile they are on other than to follow the computer.
- The computer will tell you to head to a depth for say 5 minutes. In reality you are not going to hold exactly that depth. (I usually aim for about a foot below). Therefore the 5 minutes will tick down more slowly and probably takes 6 or 7 minutes to clear.
- The real challenge comes in when you need to break the deco because of an external factor (not enough gas, surface swell, poor weighting, or anything else). Then what?
- Some divers don't recognise the deco screen from their computer and don't register what it is telling them.
- I have seen two identical computers with identical settings be strapped to the same arm. The two computers came up with deco profiles that were different by 15 minutes. How much do you really trust your computer's deco planning?
- A computer may give you a stop at say 30ft. If you accidentaly go shallower for more than 60 seconds, the computer locks you out. Some might even abandon you. Now you are on your own as your computer is telling you its algorithm is no longer valid.
Yes there are a number of computers that tech divers use (you dive two computers on one arm if you are doing this). Most plan dives using software to cut specific tables instead of relying on the computer.