You can make longer, deeper and safer dives by borrowing techniques from scuba's cutting edge.
The next time you see divers suiting up with double tanks and redundant computers, pay closer attention. Even if you never plan to explore beyond traditional recreational diving limits, there's a lot you can learn from tech divers. In the quest to dive deeper, longer, farther and--most importantly--safer, technical divers have become the virtual test pilots of scuba. Here are five things recreational divers can learn from their technical cousins.
Learn from Your Mistakes
The equipment, the procedures and many of the diving rules in use today have largely been built upon technical diving's most significant contribution to the diving industry: accident analysis. The cave diving community began decades ago analyzing every significant accident and compiling both primary and secondary causes of these fatalities or near fatalities. This active process of learning from mistakes--and adapting training and gear to prevent future accidents--continues today in the cave diving world, and through the assistance of some dedicated volunteers, is now expanding to all fields of technical diving.
In the recreational realm, the Divers Alert Network (DAN) compiles the annual Report on Decompression Illness, Diving Fatalities and Project Dive Exploration. DAN's annual review and analysis of recreational scuba injuries and deaths forensically dissects--with charts, graphs and reports--the state of dive safety. The report is free to DAN members at its web site, www.divers-alertnetwork.org.
Manage Your Gas Supply
Technical divers have long used a gas management rule called the rule of thirds. Taken literally, the rule means you use one-third of your gas supply to explore, one-third to swim back to the exit point and hold one-third of your gas in reserve for delays, emergencies and ascents. Not surprisingly, a number of the recreational agencies now teach this same rule, especially for dives deeper than 60 feet.
Slow Your Ascent Rate
The ongoing trend toward slower ascent rates and deeper stops to provide a hedge against DCS has its roots in technical diving. As tech divers experimented with mixed gases and sophisticated dive planning software, they began to notice safety benefits in slower ascents and deeper stops. Driven by the experience of technical divers, several recreational training agencies now advocate ascent rates as slow as 30 feet per minute and some of the more progressive recreational agencies have also modified their recommendations to include a deep stop.
NAUI led the way with its recommendation that recreational divers make a one-minute stop at half their maximum depth on dives deeper than 40 feet. In technical divers, deco stops have been shown to improve the efficiency of decompression time. For recreational divers, it is theorized that the deep stop will help prevent DCS by preventing the formation and growth of bubbles of dissolved gas. For more information on deep stops, see "One Minute to Safer Diving" in the December 2003 issue of Rodale's Scuba Diving, or on-line in the training section of www.scubadiving.com.
Breathe Something Other Than Air
Nitrox cylinders are now as common on dive boats as smelly wetsuits, and nearly every recreational training agency offers courses in diving with oxygen-enriched air. Quite a change from 1995 when Skin Diver magazine labeled nitrox the "Black Gas."
The idea of replacing some of the air in a diver's tank with oxygen in order to provide a hedge against DCS was surprisingly controversial, given its roots in scientific diving. Under Dick Rutkowski, former deputy diving coordinator at the National Oceanic and Atmospheric Administration (NOAA), nitrox became widespread among scientific divers who needed to safely extend their bottom time in order to collect data.
When Rutkowski retired from NOAA in 1985, he founded the world's first training agency dedicated to technical diving and offered nitrox training to the public. In the process of overcoming the negative hype surrounding oxygen-enriched air, he also gave us one of his other significant contributions to diving--a now-famous quote--"Science always wins over bullshit."
Today, basic nitrox certification is considered a purely recreational pursuit. Any open-water diver can learn to use nitrox blends of up to 40 percent to safely extend bottom time. Nitrox-compatible gear is readily available and most major dive stores offer nitrox fills and training--all thanks to the demands of tech divers.
Buy Better Gear
The specialized needs of technical divers have led to several innovations in gear. The most notable may be the back-buoyancy or wing-style BC. The stable face-down swimming position and the clean, streamlined front harness of technical BCs are now favored by thousands of traditional recreational divers.
Other examples of gear that has crossed over include bailout bottles such as the Spare Air and EAS system. Both are essentially miniature versions of the larger stage bottles carried by technical divers. And even the octopus can arguably be traced to cave divers, who were the first to make extensive use of alternate gas delivery systems.
What Is Tech Diving?
Technical diving is generally defined as diving outside the realm of traditional sport diving limits. This usually means the completion of dives requiring staged decompression stops; the use of gases other than air and recreational nitrox (with 40 percent or less oxygen); the extended penetration of overhead environments like caves and wrecks; or dives deeper than 140 feet.
The inclusion of staged decompression diving is only accurate in the United States and a few other locations. In most of Europe, staged decompression diving in relatively shallow water is considered a routine recreational diving activity.