Why do you do technical diving?
By Andrew Cavell – Yorkshire Rec + Tec

I have often been asked by divers, “why do you do technical diving?” The response I give them is generally something to do with shipwrecks.

The truth is there is not one definitive reason for people to go “Tech” some people are interested in deep exploration, some in cave exploration, some in wreck exploration……. The common factor with each of these is exploration.

As a diver we all have an interest in the underwater world and enjoy being somewhere that other people cannot go without the skills that we have, this is very similar to the concept that draws divers to technical diving. Recreational divers are restricted to a 40 meter limit as far as depth is concerned and to remain within a no-decompression limit (NDL) with dive duration. These two factors along with a limited air supply (single cylinder) generally mean people who want to do more exploration cannot do so as a recreational SCUBA diver.

A big misconception with technical diving is that only big muscular Spartan-like men partake in this genre of the sport. This could not be further from the truth, technical diving is for anyone who has a particular interest and wants the most thorough training to enable them to enjoy their hobby more. Some people may never, ever want to venture beyond 30 meters, but want to stay at that depth for much longer than their air and no decompression limit (NDL) allows them to. This is becoming a more and more popular reason for people turning to technical diving as technical training becomes more accessible.

In the not so distant past there were very few technical diving instructors, the ones who were trained to teach these courses were either constantly booked up or charged too much for the vast majority of people to be able to afford. With more and more agencies now offering technical level training the price has inevitably dropped to manageable levels for the courses and has opened up to a wider range of people to now get involved with this area of diving.

Though the price and availability have come more into the mainstream there is the attitude in some diving committees that the level of training has dropped below par and that the costs reflect this……… Again this is a massive misconception, as a technical instructor through the largest technical training agency worldwide TDI (technical diving international), the training we must complete to become instructors in this discipline are very tough. Rightly so as this genre of diving takes people beyond the safety offered by recreational or sport diving.

A brief insight into “tech”

With technical diving we have a high emphasis on risk management, stress management, dive planning and much more. Through the various training courses you will progressively gain more and more experience in how to deal with all problems that can occur whilst underwater. A “tekkie” is not a solo diver, but an individual who is a self sufficient member of a team. This means you no longer rely on your buddy to help you out every time (there are exceptions) and you can very easily deal with any issues that may present themselves whilst on a “tech dive”.

You will hear technical divers speaking an alien language of 3 letter acronyms and words that sound like they have been pulled from a hat and joined together. This in its self can be quite daunting and may be enough to put people off giving it a go. The thing to remember is we all start somewhere, and prior to you starting diving, would you have known what people were talking about if you heard someone say “my regs need a service and my cylinder has gone in for a hydro” or “watch you NDL’s” This is the same with technical diving and is nothing to be scared of.

A few of the more frequently used acronyms and phrases are as below:

  • Deco – A divers decompression obligation, or the time it will take with mandatory stops to reach the surface.
  • EAD (Equivalent Air Depth) – A calculated theoretical depth that you plan a dive to whilst using enriched air nitrox.
  • Shut downs – Isolating a malfunctioning piece of equipment whilst underwater.
  • Bubble check – A check performed at the beginning of each dive
  • S-drill – Another check performed at the beginning of each dive along with the bubble check.
  • Twinset – 2 SCUBA cylinders joined by an isolator manifold and steel bands to hold them together, provides twice the gas and lots of redundancy.

There are many more but all are pretty self explanatory and should you decide technical diving is for you, you will be soon speaking in this strange language too!!!!

The most obvious difference between technical divers and recreational divers is the equipment “tekkies” take on dives with them. This is from the number of cylinders (more than 1, can be as many as is required for the dive), the gasses within these cylinders (Nitrox*, Trimix*, Heliair*, Heliox*), number of gauges (1 main computer, 1-2 depth/bottom timers, watch with second hand), wrist slate/underwater notebook with dive plan and back up/contingency plans should there be a bottom gas/deco gas loss and plans for the next deepest and next longest in case something happens where a deviation from the original plan occurs (should never happen but planned for anyway for redundancy), spare items such as mask, 2 surface markers, reel/spool, 2 cutting devices (1 knife and 1 shears).

You may think “why the hell do you take all this and where the hell do you keep everything”.

The answer is we have our own places for keeping everything; the most important thing to think of is that you can very easily get to everything with both hands if you need it. Agencies like GUE (global underwater explorers) insist on all their divers to dive with the same kit and configuration to make sure everyone knows what is where on all members of their team. Other agencies state that you must be able to reach everything whilst being streamlined.

Below is my configuration, this is just a “for instance” and is not to say it is everyone’s choice but it is proven to work for me:

  • Left drysuit thigh pocket – Emergency SMB – Knife – Shears – Spool
  • Right drysuit pocket – Wet notes – Spare mask
  • Backplate – Primary SMB/liftbag
  • Right hip on harness – Canister light
  • Right shoulder on harness – back-up light
  • Rear/bottom “D” ring on harness – Primary reel
  • Right arm – Main computer – Compass – watch
  • Left arm – back-up bottom timer/s

This configuration ensures minimal snagging hazards and is a very streamlined configuration that I use on EVERY open water dive, even if it is a shallow dive for fun, this keeps up the practice and means I am thoroughly versed in the usage of this configuration.

In summary technical diving is a more advanced version of normal SCUBA diving with more equipment and a more thorough knowledge base. It is absolutely not for just big men with big beards and it does enable divers to access certain areas they wouldn’t have been able to go without the training. It is very true it is not for everyone but for those thinking………. “What’s down there”, “I wish I could go to that wreck”, “I would love to know what cave diving is like” and many more similar questions similar to these. I would like to take this opportunity to say welcome to our world and we look forward to seeing you in the fantastic world of technical diving sometime in the future.

Article written by British TDI technical instructor

Andy Cavell


*Nitrox – a breathing gas containing differing amounts of Nitrogen/Oxygen

*Trimix – a breathing gas containing differing amounts of Helium/Oxygen/Nitrogen

*Heliox – a breathing gas containing differing amounts of Helium/Oxygen

*Heliair – a breathing gas containing differing amounts of Helium/Air