Equipment needs certainly vary, but the adventure is always a constant!
You have probably seen the illustration:
One diver is covered in gear. He is in a drysuit, has a pair of twin cylinders on his back, a stage bottle strapped to his left side, one regulator second stage hanging from a shock-cord necklace, two bottom-timers on his wrist and an assortment of “accessories” stuffed into pockets or occupying what little real-estate is left on his two-inch wide simple webbing harness. He has a serious “all business, no fun” look on his face – A look that reminds me of the expression worn by the male models in old Sears mail-order catalogs in the sixties and seventies.
The other diver is standing in what looks like a 3 mm wetsuit with a stab-jacket, aluminum 80, and a smile on his face.
I have never completely understood the purpose of this drawing (is it to warn people about technical diving?). What I do know, however, is that it has been the source of a lot of questions from perspective students for tech programs over the years, especially candidates for TDI Intro to Tech (I2T) classes who usually ask, while pointing to Mr. Serious, something to the effect of: “Do I need all that stuff to do this class?”
The answer of course is a resounding no! The gear requirements for taking part in an I2T class can be more or less the same as for regular sport diving, but there are a few notable differences between the type of gear used by the average sport diver and the choices more commonly found on divers who venture into technical diving. Understanding what they are, is a good first step towards understanding what tech diving is all about.
One of the first major differences is exposure protection. A simple definition of the difference between tech and sport diving is tech equals more bottom time. Since it boils down to more time on the bottom, staying comfortable and warm takes some additional care, especially in regions with a thermocline!
Technical dives also often include a slow ascent with more than one stop on the way back to the surface. Partly because of this, many techies diving in cool to temperate water opt to wear a drysuit and pay particular attention to thermal protection for their core and extremities.
Of course, a drysuit is no definitive indicator that a diver is a techie because plenty of divers who have no desire to venture “deeper and longer” invest in one. A drysuit is often favored over a wetsuit for both additional warmth and more controlled buoyancy characteristics. (Remember that neoprene compresses as depth increases and therefore you can almost read the Sunday paper through a 7 mm wetsuit at 60 metres [200 feet].)
Perhaps the most noticeable difference is the number and size of scuba cylinders a technical diver carries. It all relates back to the first rule of scuba: Keep Breathing.
At great depths, making sure you have enough gas to keep breathing usually calls for a lot more litres or cubic feet than can be squeezed into a single cylinder. Couple this with the practice of optimizing off-gassing during ascent (that’s a fancy way to say breathing nitrox on the way up) and our tech diver now has to carry one or more cylinders filled with decompression gas.
A more subtle difference is regulators and the way they are set up. First off, technical divers tend to be very specific about which make and model of regulator they buy (and remember, they buy a bunch of them for all those tanks they carry!). The primary reason is a need for high-performance and a piece of kit with the ability to deliver large quantities of gas at depth. Consequently, tech divers tend to shun regulators that are perfectly fine for a warm-water reef dive to 30 metres / 100 feet, and opt instead to pay top dollar for regulators designed to minimize work of breathing.
Another factor in the quest for the perfect regulator is the routing of the hoses coming from the first stage. The goal is to find a design which keeps low and high-pressure hoses as streamlined as possible. Tangles and big loops of hose coming out from a first stage, looking like the arms of an octopus, are not cool in the tech arena.
This requirement further thins out prospective brands. Final choices for regulators on primary bottles as well as deco bottles or stages often come down to three or four brands and specific models within those brands.
One last difference for regulators is that they are DIN verses yoke. Tech divers use DIN because the connection between the tank’s valve and the first stage is more solid and the Oring keeping things gas-tight is trapped. A yoke first stage is far more likely to become unseated than a DIN valve, and I have seen – very recently – a yoke regulator blow off a stage bottle below 200 feet after the mildest of taps against a rock wall during descent. Not a reassuring sight.
Instrumentation is usually very different too. Techies carry depth gauges/bottom timers and or dive computers on their wrists rather than in a console, and they usually carry more of them. It is not unusual for the one integrated personal dive computer carried along by an SDI open water diver to be replaced with two multi-gas, multi-function computers or a computer backed up with a digital bottom timer and a set of tables cut with proprietary PC or Mac based decompression software. The hottest and latest technical dive computers are capable of programming for as many as ten different gases, track decompression obligation second by second, download graphics seamlessly to a PC or Mac, and can have software updated by connecting to the internet. Some even help pass the time during decompression by allowing divers to play simple video games. We have come a long way from a bourdon tube, baby!
Other “stuff” that you may find very different on the average techie are accessories and how they are carried. Sheer volume dictates carrying accessories differently, and a need to streamline and lessen entanglement potential also means that pockets, pouches and bolt snaps are de rigueur. A quick inventory includes an underwater notebook, DSMB (delayed surface marker buoy) and spool, a spare low-volume mask, backup bottom timer and depth gauge, spare cutting devices and backup lights.
Now this is not to suggest that a tech diver takes everything he or she owns into the water. There are pretty well-established guidelines that dictate only taking what is required by the dive plan, but if that plan does call for something, it has to be accessible as well as functional.
This brings us to one other important issue for all tech gear: It is serviced regularly, inspected and tested before every dive, and replaced if found defective. There simply is no room for any piece of equipment lashed together with string, bailing wire or duct tape on a technical dive.
So what are you waiting for? Find a TDI facility of your own and embark on a whole new adventure! https://www.tdisdi.com/index.php?did=16&site=2