How to best use a computer to be a good diver

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Doctor Rig

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I just don't log dives
I just got finished reading a good thread “Are dive computers making bad divers?

Good discussion, which leaves me with a simple take-away: computers are very capable and far better than tables, enabling improved diver safety, but divers could make better use their computers. But I want to hear more.

With this thread, I’d like to hear suggested best practices for using a dive computer for the recreational diver (1) before, (2) at the beginning, (3) during, (4) at the end and (4) during the surface interval following a dive. Perhaps input on, what to review, what to watch for, how to react to, in various scenarios.

If anything like this exists, maybe we could review it.
Here's a start.
  1. Understand how your computer handles adjustments for conservancy and set them appropriately.
  2. Know how the dive planning function of your computer works and use it, at least until you have done enough dives to be able to make good predictions.
  3. Understand that the basic difference between a computer and tables is that when you dive tables, when you leave the bottom and head up the dive is technically over, but when you use computers, you may have a lot of diving ahead of you. If you have 3-4 minutes of NDL left when you leave the bottom, you may have loads of time after you ascend 30 feet. Pay attention to this over many dives so that you can learn to predict remaining dive times as you ascend on multilevel dives.
  4. If you have an air integrated computer, pay attention to air time remaining and see how that changes with depth. You will be gaining an intuitive feel for your SAC rate without actually measuring it. (My first computer was an air integrated Suunto Cobra, and by doing this, I had a very good sense of my air consumption rate before I even knew there was any such thing as an air consumption rate.)
  5. Know how your computer will alert you to an unplanned decompression obligation and how it will guide you to the surface. When it happens is not the time to be figuring it out.
  6. If your computer has a Surface Gradient Factor feature, understand how this can be used in lieu of a safety stop timer.
  7. Know how to set nitrox quickly, without having to haul out the manual.
Just as an explanation for my previous post, the RTFM advice sounds good, but it might not be as helpful as you would think. My first computer (Suunto Cobra) had the most poorly written out manual possible. It was filled with information I would never need to know in a million years, and sprinkled throughout that chaotic mess, with no particular emphasis, was the stuff I really needed to know.

What you need to know is lost in the overwhelming pile of stuff you don't need to know. What you should do is open the manual with specific questions in mind, like the items I listed above, and look for the answers.
...and let's not forget what videos on u-tube can provide. As an engineer I'm pretty good at understanding technical documents but Shearwater's explanation of the tissue compartment inert gas graph left me wondering. I found Shearwater's video about the graph and watching it solidified my understanding.
Not sure if all computers are compatible with this, but I learned a lot about using my Peregrine by just playing with it. Sat down with the manual on my iPad and just played with the settings and such. After I dove it a couple times, I went back and tweaked some stuff.
Yeah. I did the same thing with my Perdix. Playing with it, while not giving you much understanding (until you read the manual), at least you know where the settings are and how to go through the various menus.
Most recreational dive computers will lock you out from further diving for 24-48 hours if you make them unhappy, such as by omitting required deco stops. Make sure you understand what might trigger such a response so you don't do it inadvertently due to user error, which is probably more likely than actually missing a significant amount of required decompression on a recreational dive. They might, for example, reset your mix to 21% after some time period without you noticing while you're actually diving with a richer mix.

If you get a Shearwater, spend some time learning about and watching the tissue loading graph. It will tell you a lot about how the computer is reacting to multiple dives over multiple days.

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