The previous discussions about dive tables and computers included a lot about diving with computers. Keep these points and procedures in mind when you use a dive computer:

1. Computers are sophisticated calculators with depth gauges and timers that calculate theoretical nitrogen in the body. They're no more or less valid than dive tables and they don't track anything physical in your body. The recommendations for conservative diving with tables apply to computer diving.

2. Don't share your computer. Each diver needs an individual computer. A computer tracks theoretical body nitrogen

In this subsection on Special Dive Table and 
Computer Procedures, you learned: only an emergency procedure.
. You should make a safety stop at the end of.
. For recreational divers, decompression is.
. Virtually all dives (except when an emergency prohibits it). 
. Diving at an altitude greater than 300 metres/1000 feet.
. A safety stop is a pause in your ascent between 3 and 6 metres/10 and 20 feet for three minutes or longer. 
. Follow the recommendations for flying after feet for diving conservatively, and stay up to date with the most current recommendations. 
. Plan cold/strenuous dives with the RDP as though the depth were 4 metres/10 feet deeper than actual. With a computer, be conservative using the most appropriate method for your computer.
. Consider a safety stop mandatory if you dive deeper than 30 metres/100 feet or reach any limit on the RDP or your computer as it rises and falls with each dive and surface interval, so it must stay with one diver for the entire dive day - you can't swap between dives. You can't share a computer within a buddy team either because it tracks depth quite closely. It will only be accurate for the diver wearing the computer.

3. Follow the most conservative computer. Surface or ascend when either computer - yours or your buddy's - approaches its no decompression limit. If you follow the least conservative. you're in effect sharing that computer, which you shouldn't do.

4. Don't turn your computer off between dives. Most won't let you, hut if you take out the battery or shut the computer down, it loses its memory of your previous dives and your residual nitrogen. You'll have to allow all residual nitrogen to leave your body before resuming use of the computer. Your computer will shut it self when it calculates no significant residual nitrogen remaining.

5. Make your deepest dive first and plan successive dives to progressively shallower depths. During a dive, start at the deepest point and work your way shallower. As recommended by the dive medical community, avoid going from shallow to deep. Computers will continue to give you no decompression times if you break this guideline not because it's okay, but because it's better than no data at all. Avoid making multiple deep dives with short surface intervals between them.

6. Stay well within computer limits. Always try to have five or more minutes no decompression time remaining. If you let it near or reach zero, you've pushed the limits even though you'll have plenty of no stop time when you ascend to a shallower depth.

7. If your computer quits, you may need to stop diving for 12 to 24 hours. If it quits during a dive and you've been staying well within the no decompression limits, ascend immediately to 5 metres/17 feet, make a safety stop for five minutes or more and surface. You can't simply grab another computer because it won't know how much residual nitrogen you haw. Follow the manufacturer's instructions.

8. Take the RDP for backup on dive trips so you can resume diving the next day if your computer fails. If you computer fails and you've been tracking your depths and times. and your dives stay within RDP limits, you can continue diving using the RDP. Otherwise, you'll probably have to wait until the next day for residual nitrogen to clear before you resume diving. Although it's computers you dive resort to have dive computers you cant rent, don't count on it. Take your RDP so you can be sure you won't miss out. Preferably, take The Wheel so you can plan multilevel dives that maximize your no stop time.

9. Keep thinking. Dive computers can fail just like any other piece of' equipment. Don't blindly accept everything your computer says, especially when it appears way out of line with a buddy's computer or your previous experience. Read the manufacturer's instructions completely before using your computer, and follow what they say. You can learn more about the theory and use of dive computers in the PADI Multilevel Diver course.