Deep diving is sort of a relative term, as a deep dive for one person may not be a deep dive for another. Books have been written about deep diving and there has been much controversy over the years with respect to how to deep dive, what gasses to use, decompression techniques, etc. If you’ve browsed around on some of the training websites, you probably noticed a specialty certification called Deep Diver. What does that mean exactly? For training agencies like NAUI and PADI, this certification teaches you to dive from 60 to 130 feet (18 to 40 m) following no decompression requirements. You also probably noticed that if you were to take an Advanced level certification, you would also be exposed to at least one deep dive.
The technical side of deep diving is much more involved. Deep diving in the technical community can range from 130 to over 500 feet deep (40 to 152 m). Special equipment, training, gasses, decompression requirements, and mind set are required for this level of deep diving. Deep diving in the technical community is not about going deep, it’s about having to go deep to explore the wreck, cave, blue hole, or wall. If you have the desire to explore wrecks, caves, or whatever that lays in deep water, getting the proper training to safely operate and return from these depths is a must.
In past years, there was a very controversial approach to deep diving, which involved diving deep on standard compressed air. The thought was that you could teach someone to resist the effects of nitrogen narcosis and build tolerances to the elevated partial pressures of oxygen. There are individuals with record deep dives on air and there are individuals with gravestones over their heads because they plunged to deep on air. Some argued at the time that mixed gasses were too expensive and not easy to come by, so diving deep on air was the only choice. Others simply decided that the risks were worth it and took the chance, while some forged ahead with mixed gasses and proved that deep diving could be safe when the proper gasses and techniques were used.
Today, trimix is used extensively for dives deeper than 150 feet (45 m). Many use trimix when diving any deeper than 100 feet (30 m). Training agencies like IANTD, GUE, TDI, and NAUI offer technical trimix courses, which teach you the requirements for safely diving deeper and performing staged decompression. Deep diving using trimix and the proper decompression gasses has proven itself time and time again. With trimix, nitrogen narcosis is drastically reduced or eliminated and oxygen toxicity is easily avoidable. Trimix is the only way to deep dive and will continue to prove itself into the future.