Your Dive Computer: Tips and tricks - PART 1

Push the right buttons

You should know not only which buttons to push to make your computer work, but also which mathematical model or model derivation it employs in making its decompression computations. There is a surprising range in models, from conservative to liberal, and these differences may not be evident at first glance. For example, a computer may establish conservative limits for an initial dive but liberal limits for repetitive diving.

It is best to learn enough about the various available models and derivations before you select a dive computer, so you are sure to choose one that is compatible with your own level of risk tolerance. Choosing one purely based on familiarity may not be the best strategy. Even if you have had good outcomes on previous dives with a computer, it does not guarantee that it will be the best one for your future diving. Accumulating knowledge takes commitment, but informed planning for decompression safety should be a top concern.

Tune in and turn on

Failing to turn on your dive computer (or to take it with you on a dive) may sound like a joke, but it does happen and can create real problems. No computer can factor in the exposure profile of a previous dive if it was not there. And any decompression model is invalid unless you start using it when you are “clean” — fully off-gassed from any previous dives. If you forget to take your computer with you on a dive early in a repetitive series, you are then restricted to using tables for the duration of that series (assuming that you are able to manually compute the exposure of the unmonitored dive). And do not even think about hanging your computer on a down-line during a surface interval in an effort to compensate for having forgotten it on an earlier dive; there may be stories about that happening, but it is not a responsible practice.

Use it appropriately

The only person who does not have to worry about taking a dive computer on every dive is the one who uses it solely as a data-logger — that is, only to record time and depth information instead of to calculate decompression profiles. Remember, however, that using your computer simply to log your time and depth data means that you must still plan all your dives using dive tables and must recompute your repetitive group status afterward, as appropriate.

You cannot move in and out of relying on your computer’s decompression computations unless it has recorded all of your exposure profiles. There are some basic guidelines that can help to ensure the safe and effective use of a dive computer. The following considerations are intended to offer a somewhat light-hearted insight into what your dive computer can — and cannot — do.

It is helpful to think of your dive computer in these ways:

•As a business competitor: Master it by learning its strengths and weaknesses.
•As a date: It must be turned on for the relationship to work.
•As a buddy: It should descend and ascend whenever, but only when, you do.
•As a personal assistant: It reminds you of rules and schedules you might otherwise forget.
•As an actor: It recites the lines without having to understand their implications.
•As a politician: Do not believe everything it tells you.
•As a hotel concierge: It will help you do what you want — but at a price.
•As a stranger: It knows virtually nothing about your personal reality.
•As a mate: Is it compatible with your friends?
•As a news reporter: It will air your dirty laundry.
•As a tool: Use it appropriately.