What is technical diving? Ask most newly qualified open-water divers and they may struggle to explain exactly what that term means. Even recreational-diving instructor candidates often don’t necessarily have a one-sentence answer.
For years, my go-to explanation was: ‘Remember the limits you learned — not to exceed certain depths and times? Technical diving teaches you to go beyond those depths and times, but plan for it.’ Oversimplified? Perhaps. So, let’s look at other definitions.
The National Oceanic and Atmospheric Administration (NOAA) defines technical diving as “all diving methods that exceed the limits imposed on depth and/or immersion time for recreational scuba diving. Technical diving often involves the use of special gas mixtures…
Technical diving almost always requires one or more mandatory decompression “stops” upon ascent, during which the diver may change breathing gas mixtures at least once…”
Within these few lines, we learn some of the key components of technical diving, such as exceeding recreational depth and time limits, choosing breathing gases and making gas changes. This definition doesn’t touch upon the need for additional equipment, which is almost a foregone conclusion.
As technical diving often involves diving deeper and staying longer than recreational divers normally would, tech divers require more gas. And, if divers take more than one breathing gas with them, it follows that they’ll need at least one additional cylinder, complete with rigging and regulators.
A single tank is usually not enough for two reasons. First, it doesn’t hold enough gas. Second, it does not offer enough redundancy if you have an equipment failure, such as a regulator or valve malfunction. Consequently, technical divers tend to use twinsets/doubles or sidemount tanks.
But technical divers don’t only take back-up tanks and regulators. Tech divers carry two masks, dive computers and/or depth-timing devices, SMBs and/or lift bags and any other lifesaving equipment.
Another crucial difference between recreational and technical diving is the amount of planning involved in either. Technical divers learn to calculate how much gas they are likely to use on their dive. This forms the basis of their dive planning. Add to that suitability of gases, equipment requirements, logistics and so much more, and it becomes clear why technical planning usually takes a bit longer.
Divers often use desktop software to produce individual dive plans suitable for each dive site’s topography and expected conditions. Plans include gas supplies, descent and ascent speeds, gas-switching depths, required amounts of gas for emergencies and more.
Technical divers must possess specialist skills, including the ability to manage several different gases. They practice this task in certification courses, as well as learning emergency skills. Like recreational diving courses, tech courses contain a mix of skills applied to most dives, including propulsion techniques, gas switching, trim and buoyancy control and emergency skills, such as cylinder shutdowns, mask switching and more.
Being able to quickly and competently execute those skills can make the difference between life and death or prevent serious injury in a technical-diving scenario. This is especially true for overhead environments, including caves and wrecks. Both are unforgiving environments where you must have sharp dive skills.
Therefore, tech divers must keep their skills fresh and practice them regularly. Consequently, you may see someone taking a twinset and two or more stage tanks to 60 feet (20 m).
Becoming a technical diver is likely to change a diver’s approach to all their diving. The TDI technical diving agency, for example, mentions a ‘performance mindset.’ This means that the diver is in control of each part of their dive. Practically, divers might conduct more thorough pre-dive checks, spend some time writing a dive plan on a slate, carry specialist computers and generally be in their own world before a dive.
While some of this becomes automatic after a while, it takes time to get there, but the reward is entry to places few divers ever go.