Though still regarded as crazy by some in the military and commercial-diving circles, technical diving, which just turned 30 depending on how you count it, is no longer considered the radical fringe. It has taken its rightful place as the vanguard of sport diving.

Today, nitrox is nearly ubiquitous among sport divers and helium is the gas of choice for deep diving – deep air diving is no longer deemed viable.

The trend today is for divers to limit nitrox diving (including air) to 30m and use a helium mix beyond that to offset the effects of nitrogen narcosis and gas density.

In fact, some training agencies have even begun to adapt helium mixes for recreational divers. Mixed-gas dive-computers are commonplace, and sport divers have also now surpassed the military to become the largest user group of closed-circuit rebreathers on this water planet.

The situation was very different when these technologies were just being introduced to sport diving, in what I then called the “technical diving revolution”.

At the time, 40m was considered the maximum depth limit for scuba. Decompression diving was strictly verboten, and the only recognised breathing mix was air.

The emergence of technical diving in the decade from the mid-1980s to the mid-to-late-1990s was arguably one of the most exciting and profound chapters in the history of diving.