Air Integrated Dive Computers

Air integrated computers, that is, a dive computer receiving wireless information from a transmitter on a regulator’s first stage, became widespread in the last decade. They were invented in the 1990s, but didn’t see much popular appeal until Suunto launched the Suunto D9 in 2004.  Today, more than twenty years later, and despite the technology having changed quite a bit, they are still frowned upon by many divers because of perceived reliability and safety issues. At MCP, we think this is unfortunate and undeserved, and as such we invite you to examine the merits and pitfalls of diving with an air integrated computer.

It seems to always be the same three issues with transmitters that worry divers: loss of signal, the risk of losing air through some sort of malfunction or rupture, and lastly, the fragility of the transmitter and related handling issues.

Looking at the potential problem of loss of signal, we need to understand what this problem is and what it isn’t. We are not talking about a loss of air, only a loss of signal. Granted, it’s an inconvenience, but the air is still safely in the tank, right where you need it.

In scuba diving, we believe you shouldn’t check your gauge to see how much air you have left. You should check your gauge to confirm how much you have left. Keeping track of your air, knowing how much you have left, is a skill you acquire as you become a better diver, because air consumption really isn’t arcane diving lore, privy only to the most hardcore divers. It’s pretty basic, and everyone can learn it. This sort of sixth sense in scuba diving can and should be trained no matter if you dive in the Philippines or in the frigid waters of Norway. You can see a shift towards this sentiment in the updated PADI open water course as well, as students are at all times expected to know (within a reasonable margin) how much air they have left.

What this means is that even if you lose the signal, you should still have a very fair idea of how much air you have left. Of course, it’d be prudent to alert your buddy you have an equipment problem and then calmly ascend to do your safety stop and abort the dive, rather than continue the dive. However, compare that to the rupture of a high pressure hose feeding a normal submersible pressure gauge. A ruptured hose will deplete your gas quickly, plus the loud bang and violent hiss of bubbles may cause some divers to panic, adding further danger to a somewhat tricky situation. (Many divers erroneously assume that a tank will empty faster if the ruptured hose is a high pressure one, rather than one that feeds the power inflator or regulator. In reality, the opposite is the case: the pressure may be greater, but the smaller orifice of the high pressure plug makes all the difference.) A burst hose is a serious occurrence, and the diver needs to act immediately, aborting the dive and, of course, preferably securing the octopus of the diving buddy, just in case.

We’d argue that losing certainty about exactly how much air you have left is better than having certain knowledge that you’re losing air very quickly. And this isn’t conjecture: a high pressure hose feeding a gauge is much more likely to fail catastrophically than a transmitter. Parts potentially prone to failure are multiple o-rings, the actual hose itself, and of course the mechanism inside the gauge, any of which can give and cause loss of air. Compare that to the transmitter, which has one o-ring. One. And no hose, which incidentally is the part most likely to fail.

One objection to transmitters that often pops up is handling issues based on the fragility of a transmitter. The argument is that it’d be a bad idea to try and lift a full tank, BCD and regulator assembly by the transmitter, and that, by the very design and position on the first stage, a clumsy deck hand can easily misuse the transmitter as a handle. Although transmitters are fairly sturdy, we agree there’s no reason to take any chances. When our instructors teach scuba diving, they always make it a point never to lift or carry a full assembly by the first stage anyway, since you’re likely to damage hoses and o-rings, especially if the unit is heavy. When our instructors dive somewhere they expect someone else might be handling their gear, for example when boat diving on a dive holiday, they make sure there’s no way anyone can get it wrong. They tell the people who will be handling their gear ahead of time how to lift it, and more often than not, that’s met with a knowing smile and the assurance that this is how they always handle scuba gear with transmitters. Transmitters aren’t really a novelty anymore. Regardless, if you worry about it, carry your own gear, or use one of these small life hacks:

• Disconnect the first stage from the tank after you’re done diving. That way, anyone wanting to move the complete unit will have to use the tank valve, or spend time reattaching the first stage.
• When you’re in the water and want to pass your unit up to a boat, hold the unit by the transmitter yourself. That way, the deck hand will have to grab hold of something else.

Lastly, to the best of our knowledge, no dive shop in the Philippines offers rental of integrated computers, or has one as standard on their dive equipment, and neither do we at Marine Conservation Philippines. That’s not because the technology isn’t good, but because transmitters are still fairly expensive. It’s also worth remembering that everyone can read a gauge, but not everyone would be immediately able to use a dive computer they aren’t familiar with.

Thanks for reading.