Technical Diving Lore

The Term 'Tech Diving' was coined in the USA and nowadays the term can be used to describe a minority of divers doing diving vastly different from rec. diving. Aqua Corps a magazine dedicated to Tech Diving describes it as "A discipline that uses special methods and equipment to improve diver safety and performance, enabling the user to conduct dives in an environment and perform tasks beyond the scope of traditional recreational diving limits".

However under some definitions there are varying degrees of Tech Diving. A respected diving scholar John Bantin has listed a ten point Technical Diving Curve and to all intents and purposes it is a benchmark for what level of Technical diver you are. Or more commonly known as the...

Mark of The Tech Diver

The Mark Of The Tech Diver (MOTT) can sometimes be a broad one though, for the purposed of argument and keeping the Status Quo a true 'Tekkie' should be considered in the 7- 10 range. The MOTT is reproduced below...

1. Leisure Diver - Non Technical. Little equipment apart from the basics required. Usually simple and straightforward. Most divers are at this level.

2. Dry Suit Diver - Divers who use a dry-suit. Stepping into Tech diving territory.

3. Deco-Stop Diver - Organisations such as BSAC teach decompression techniques to its divers. Deco stops real or simulated are a signature of Tech Diving.

4. Nitrox Diver - Divers who breath gases of more than 21% O2 to lessen Narcosis and extend bottom time. Added hazard of O2 Toxicity.

5. Semi-Closed Rebreather - Less bubbles, longer bottom times and more forgiving than a Closed Circuit Rebreather. A good intro for divers wanting to move into CCR territory.

6. Regulator Switching Diver - A diver who uses a Twin Set/Doubles with independent Regs/Manifold. Also divers who carry pony bottles as a reserve.

7. Deep Divers - Tech Divers who go deeper than Recreational limits using tec deep diving techniques and equipment. This is where the true mark of Tech Diving begins.

8. Stage-Deco Divers - Considered by many to be the Zenith of Tech Diving. Utilising multiple cylinders, air, nitrox and 50 - 100% O2. Stage Deco techniques, serious planning and complex dive schedules are utilised.

To what numbers 9 and 10 are visit : Diving Lore - Mark Of The Tech Diver

Technical Diving Equipment

Its been remarked that in diving the snorkelers are the gazelles, the recreational divers are the horses and the tech divers are the elephants! While this is not totally accurate it gives an idea for the comparison. Equipment for technical diving tends to be complex in arrangement, heavy and requires total confidence and skill from the user to work effectively. A backup for almost every item is taken. In the event of an piece of gear failing the dive can be aborted without fuss and safely, as opposed to a hasty emergency procedure which often governs recreational diving.

Much more scope for adjustment and customisation is the trend yet there is a standardisation to the rig (as tech gear is often referred to) so a tech diver from another land speaking a foreign language should in theory instantly know where what is in the event of he/she needing something from a team member whilst on the dive.

Technical Diving Regulator/DV

The operation and look of regulators/DVs prefered by tech divers is similar to the recreational diver counter-part but with some marked preferences.

Due to the deep depths involved and the colder water Tech divers prefer to dive with balanced diaphram type-environmentally sealed regulators. These are usually more expensive than conventional piston operated regulators but they are much less likely to free-flow. Having a balanced reg. allows the diver to breathe more easily at depth with the ambient pressure kept fully balanced throughout. A good example of one is pictured above and it features a side-stream exhaust, vital for keeping those pesky bubbles away! The 1st Stages should be DIN-type. These allow more pressure (300+ bar) and are much more secure than yoke type. The fine thread is a little tricky for some though! Especially on a cold rocky boat!

Dive Cylinder - Twin-Set

There will be a twin-set of cylinders or doubles (normally 12 litre capacity or higher) for the extra gas requirements which are rigged up to 'Wing' BCD with a heavy duty harness. A thick wetsuit (5mm semi-dry or higher) or Drysuit is the norm. due to the deeper depths and/or the extended duration underwater. No snorkal is carried; mainly due to the increased drag and interferance. Extra cylinders side mounted are often carried for extended range and deco requirements. The cylinders should without exception have DIN valves fitted especially the Stage/Deco cylinders! Yoke valves and fittings commonly seen in Asia Pacific and the Americas are no good for Tech Diving; the method of fitting to a cylinder is a liability in a Tech Diving environment. I personally know of a well-known tech diver who almost became unstuck because of this!

To complicate matters further cylinders can come in capacities ranging from 1.5 litres up to a mighty 18 litres! Typically in rec. diving 12 litre cylinders are the norm with the smaller cylinders used as a bail-out and the larger ones for deep/technical diving. As well as sizes cylinders come in two size catagories: Short or 'Stumpy' (pictured) or Long. Smaller people (5"7 and below) often prefer the shorter varient and vice versa.

The cylinder itself is filled (via a compressor) with compressed air to between 200 and 300 bar. With such a great pressure only cylinders made for diving should be used. It is also necessary to have a visual inspection each year and a hydrostatic test every five (Regulations are subject to change).

With good care and maintanence a cylinder should last for a life time.

To see more visit : Diving Lore Tech Diving Equipment

Tech Dive Training

There are a broad range of organisations that offer tech diving training and each will differ to an extent in what they teach and how they do it so don't take what I say as gospel fact, but more of a guideline in whats expected. I'm not about to go into the intricacies of how to tech dive but I will give you a good idea of what the deal is and what's expected.

To even consider yourself tech diver material you should have at least 100+ dives, a chunk of experience in deep diving and by 'deep' I mean 30 meters and over and have dived on EAN/Nitrox.

Training to be a Technical Diver should not be taken lightly, it is not an attendance course nor is it a pay-and-purchase certification, it requires total dedication from the aspiring wannabe-tech diver. Before you ask yes, failures and referrals are commonplace. It isn't for everyone nor is it meant to be, you have to be of a different mentality and mindset or at least prepare to adjust to one.

Keeping your cool while all about you is going pear-shaped is crucial to any recreational diver. Now introduce that on a technical dive at 50M+ with a heavy narcosis loading in zero vis. with a full panoply of tech gear to manipulate and a complex run-time to follow! You begin to understand that its no joking matter embarking on tech diving course! Sounds like I'm putting you off a little? You bet! Tech Diving's not for the casual diver who see it as a trophy badge, you don't have to be undertake a tech diving course to become good at what you do on the recreational dive circuit. A perfect example of this is the late Jacques Cousteau who is considered the master/father of recreational diving.

The first thing you'll need to come to terms with is the shear weight and difference in equipment configuration (see below). A manifolded 'twin set', steel plate harness with a stage/deco cylinder clipped each side, all the regulators and ancillaries plus all the usual equipment for a dive can see you carrying over 60 kilos / 130pounds! A staggering weight by anyone's standards. Strength helps, as does technique and underwater you'll look like the man from atlantis, but that's all part of tech diving!

Its not just about the practical aspects though, the theory side of technical diving is a mathematicians paradise or a school kids nightmare! The equations and formulas to work out gas consumption rates, gas requirements, Surface Air Consumption can build-up to be more tricky and cunning than a sack of weasels! Add to this merry lot decompression schedules, back-up schedules, run-times and bundle them all together into a workable dive-plan, and you will begin to understand why its called Technical Diving.

Skills underwater that require total mastery are numerous, among the most critical is buoyancy. Not least because all the drills taught from gas shut down to stage and retrieval of cylinders culminate in a test whilst in mid-water neutrally buoyant, not easy. The error margin for holding neutral buoyancy varies but either side of half a meter (1.5 feet) is a typical benchmark that is set. The reason for this, you might wonder, is because if a tech diver is decompressing on a very high mix of oxygen (reduces deco. time and is highly effective) and looses his buoyancy and descends below his set depth the result (at the worst) could be a CNS convulsion and death. Conversely he could ascend too shallow and risk Decompression Sickness. The gas-switching drill to breathe off another gas cylinder for extending the no-stop decompression or actual decompression is another zone of extreme self responsibility. To put it plainly at set depths certain blends of gas are consumed from the relevant cylinder. Should you switch to the 100% oxygen (deco gas) at the wrong depth of say 30M when you should of switched to milder blend of Nitrox you will convulse, spit out your regulator and die. A very extreme example of how to ruin your day but something that is emphasised in training to ensure that you don't do it for real!

In Tech diving every diver is trained to be capable of completing his or her dive solo should the situation warrant it. This brings me to the lift bag and reel; very important, tricky to get used to and some would say a tech divers most important friend! Its the actual deployment that is critical, as in some situations you may have no way of decompressing on a shot line and a jammed reel or under-inflated lift bag is going could mean 'blue-water' or mid-water decompression; not the ideal way to spend an extended amount of time on an hour long decompression schedule! Another crucial responsibility to take aboard are the gas shut-down drills in the event of a regulator/manifold free flow.

Source: Diving Lore - Tech Dive Training

The history of technical diving started out in the late 1970s and was the result of a growing number of recreational divers who felt hampered by the conservative limits imposed on them by the mainstream diving community. Dischanted by this a small tight knit group of divers formed and are now generally recognised as the pioneers of tech diving. These men and women pushed the diving frontier to the next level of development in cave, wreck and deep diving. Deep diving techniques, modified decompression models (inc. deep stops) for the mixed gases used, the ways of dealing with potentially lethal situations at extreme depths and overcoming them. Many more became tried and tested and by the end of the 1980s tech diving had become a very exclusive form of diving. Experienced tech diving mavericks where quietly developing the techniques, methodologies and strategies for deep, confining and often outwardly hostile depths.

By the 1990s the technical divers were establishing themselves fully in the diving community, this is partly because many of the technical dive schools became established at this time and partly because they saw that a niche was there for technical divers. Technical diving is now more 'mainstream' yet has managed the balance of becoming open and available to those interested yet remaining exclusive and demanding a high standard from those wishing to become a Tech. Diver. Even now in the 21st Century it is among the Tech Divers who are exploring new methods and ways of pushing the envelope. A recent example of this was the 2003 record breaking deepest dive open circuit in open water. The diver in question used customised dive tables and planning with modified tech diving equipment. The result was a staggering 300+M (and an absolute Titan Decompression schedule!).

A defining feature in Tech diving from its recreational counterpart is that there is a considerable greater risk and danger from DCI, drowning, O2 toxicity, narcosis and general injury. Compared with Tech Diving Recreational Diving doesn't even come close to the mindset, skills and mastery of the dive. A typical recreational dive is often done with some minor planning and gear configuration and typically involves sightseeing the local marine life. A technical dive on the other hand can involve several hours of planning, intense equipment familiarity and a mission to explore an unknown sea region/wreck/cave network. Often before the actual mission (as tech dives are often referred to) work-up dives are carried out to re-familiarise tech divers who haven't dived in a while or are unused to the conditions. Tech divers can reach depths beyond that of recreational limits allowing them to dive previously untouched dive locations. To combat the risk factor involved Tech divers take a number of redundant safety features to lessen the risk involved should an emergency occur.

Terms used to describe technical diving include - Tec, tek and tech diving

Source: Diving Lore Tech Diving