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Introduction to Technical Diving

"Myths and Legends"

On the night of September 9th 1983 a couple approached Fontaine de Vaucluse, a submerged cave system in France. Not just any cave system but one of the deepest caves known to man. They went there at night because the powers to be did not want the man to dive.

That night, the man Jochen Hasenmeyer entered the water alone leaving his wife by the waters edge waiting. Nine hours latter he surfaced, they packed his gear and silently left that great cave system as though they had never been there. The only evidence of their passing was at a depth of 205m667ft in the form of a dated name tag manually tied to the existing decent line.

Jochen Hasenmyer had just shattered the world record for surface-to-surface untethered open circuit diving, at the same time he had just become a legend among his peers and would be admired by fellow adventures for generations to come.

What drove him to attempt such a dive many will never understand, but that same drive would lead generations of divers into what is now called technical diving?

What is Technical Diving?

The term itself was coined by Michael Menduna when he founded Aqua corps, the first magazine which covered those who choose to dive outside the boundaries set by the recreational agencies.

To give an actual description to the term is more difficult, because it has changed and will continue to change as diving evolves. For example Nitrox (Oxygen enriched air) use to be classed as technical, but is now widely accepted and used by the recreational community for the benefits it gives.

A good description of "Technical’ diving is. Dives which are carried out below 42m132ft or require advanced techniques such as gas switches, decompression or are in a overhead environment’s such as wrecks or caves.

Some models of rebreather can also be classified as technical if used in the above environments.

Training: What to Look For

Go for one of the established agencies. The two most established are both here in the Philippines. They are IANTD (International Association of Nitrox and Technical Diving) the first formed in 1985 & TDI (Technical Diving International) formed in 1993. Both offer quality training in advanced diving techniques. What should you look for in the Instructor? Well of course, he should have the necessary qualifications, but more importantly, he should be experienced at the level he is training you. He can’t teach you from a book, you are going to rely heavily on his experience in the field.

Don’t be afraid to ask questions such as: ‘What is your experience level?’ & ‘What equipment will we use?’, ‘How many dives will I get?’ (Many courses are worked out in bottom time with a minimum number of dives).

Your Instructor will not mind the questions, he will expect them.

Cost wise, don’t expect discounted courses, expect to pay a fair price for the experience and certification level of your Instructor.

If you are getting big discounts then you are properly losing out somewhere, either with the equipment being used or in the time he spends with you, or, more importantly with the time you spend in the actual environment.

You should be looking for quality training that is both challenging and informative.

Courses Offered

The names of the courses may well vary depending on the association chosen. Remember the name is not the important thing the content is make sure you are getting what you expect.

Recreational Nitrox

This course introduces the recreational diver into the use of Oxygen Enriched Air (regular air with a bit of extra oxygen added to increase the normal 21% level) normally to a max of 40%. Doing this gives much longer no decompression times and increased safety against decompression. However, this means you need to know about the effects of breathing enriched air on the body. Academic sessions cover the benefits and concerns, Physiology, Physic’s & dive planning. PADI, BSAC and other recreational agencies offer excellent courses at the basic level.

Advanced/Technical Levels of Nitrox Training

Advanced training. This level will take you out of the recreational field and introduce you to the skills and knowledge for entry level technical diving. A heavy emphasis is placed on Dive planning and discipline, monitoring of oxygen & gas demand. New equipment that includes redundancy is used (twin tanks or H valves), plus a stage bottle to carry a richer nitrox mix than the bottom gas to aid decompression and increase safety.

Water time should include about two hours of confined water training getting used to the gear and practicing skills, plus about 2 hours of bottom time in open water.

Technical or Extended range

This level constitutes the full range Technical diving. The depth is increased to a max of 61m/200ft, twin tank and stage bottles are used, and any nitrox mix up to pure oxygen can be used for the extended decompression schedules. This level demands a high level of both theory and water work. All of the above topic’s should be covered in more depth: in addition, new topics are introduced. Another lengthy confined water session is included with at least 2 hours of bottom time spent in the openwater.

Trimix Training

Helium is introduced into the breathing gas. This inert gas will buffer the effects of Nitrogen (control narcosis) and keep oxygen at a safe partial pressure. This allows very deep diving up to 91m300ft in training. Equipment used includes at least twin tanks and two stage bottles.

All of the topic’s from the previous courses are covered again in depth with additional sessions on Helium. All of the normal water work should be included, starting with air and finishing with at least 2 Trimix dives (preferably more)

Overhead Environment: Wreck/Cave

Whichever you choose, either wreck or cave, expect lots of time in the actual environment. But before you get there you can expect lots of time spent practicing line work and other skills, first shore-based and then in confined water. Many of the topics from the previous courses are covered with more emphasis on things relevant to the overhead environment, such as the specialized equipment required like and reels.

Rebreather Training

The content of the course will obviously depend on the model of rebreather. The most common unit used around S.E. Asia is the Atlantis/Dolphin semi-closed rebreather.

Relevant topics are covered, such as rebreather technology, hygiene & maintenance, Hypoxia (too little oxygen in the body), carbon dioxide and dive planning. Long sessions are spent both in the confined water and in the openwater environment.

Deep Air Training

As the name states these courses, first Basic and then Advanced Deep Air, give training to people who wish to dive safely in deeper water. These courses are designed to show the importance of using the correct equipment and include redundancy and understanding the need for gas management. Theory covers the many topics’ required to safely dive in this challenging environment such as narcosis and decompression. Heavy emphasis is placed on good diving techniques.

As with most training the name and affiliation involved is not the most important thing: the Instructor and what you are getting is. Remember ask questions and demand quality.

I hope this section will have been of interest to those who feel the need to go that bit further with their diving education.

For those that do I hope that the section on training & courses will help in the selection of your respective Instructors and agencies.

For those that don’t then I hope that hearing of some of the legends and myths of our sport will interest you.

In closing for this issue let’s remember what technical diving is all about: the safe exploration of sites beyond recreation diving.

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