The latest copy Alert Diver Magazine has an article entitled “Your Computer Fails: Now What? (I borrowed the below image from the very same article.) If you have a DAN membership you can login and view the article yourself.
The article begs the question, what happens when your dive computer dies during a dive or on vacation?
Personally my dive computer (a Vyper Air) monitors my depth, tank pressure, doubles as a compass, monitors my dive profile and nitrogen tissue saturation. I carry an extra, non-digital, compass with me at all times but that only provides a small amount of redundancy. If my dive computer were to die I’d be forced to surface (safely) and I’d be done until I could get it replaced or fixed.
To fix this situation the Alert Diver article recommends carrying an extra dive computer at all times. This provides instant access to a backup and assuming it uses the same calculations, you wouldn’t loose your dive profile information. Besides being a little impractical (the cost of owning and maintaining two computers) you run the risk of getting two computers that calculate dive profiles differently and can’t safely be substituted for each other.
For most people, including myself, it’s more practical to have backup gauges rather than a backup dive computer. Attaching an extra submersible pressure gauge (SPG) to your regulator first stage is a safe way to always know how much air you have left. Wearing a dive watch under your wet suit would allow you to monitor your current depth and ascent rates, even if it’s not exactly convenient. Putting an extra compass on a retractor would round out the most important backup devices you could carry.
Being safe while diving means trying to anticipate situations where things don’t go exactly as planned and being prepared is key. You should always be able to find your way home, know how deep you are and how much air you have – even when your computer fails.