Where When How May/June 2017 : Page 99
By the 1980’s “deep dive ﬁrst” was growing beyond a recommendation, and various convoluted attempts were made to provide a physiological rationale for what had been a purely practical recom-mendation. Furthermore, by 1984 the recommendation had been recast as a “rule,” and it appeared in both the PADI Open Water and Advanced Open Water Diver manuals. By the 1990s, the mantra of deep-ﬁrst was ﬁrmly ensconced in diver train-ing materials as well as in the psyche of divers; and no prudent diver even con-sidered violating the warning. But by this time dive computers had become stan-dard equipment, and whether by acci-dent or intention, divers were making — and getting away with — repetitive and multilevel reverse proﬁle dives. Tossing the Gauntlet In all probability, the deep-first rule might never have been challenged had it not been for the widespread use of dive computers. Although the rules say otherwise, no dive computer in exis-Overview of Reverse Profile Workshop The reverse proﬁle workshop brought together a formidable group of diving physiologists, physicians, physicists and mathe-maticians along with some of diving’s most knowledgeable ed-ucators, industry experts and diver training organization repre-sentatives. Also present were Naval personnel from the United States and other world navies, and diving safety specialists from the commercial diving industry. You can download a copy of the proceedings at archive. rubicon-foundation.org/xmlui/ handle/123456789/4244. tence explodes, calls the police or ceases to function if the user engages in a reverse profile dive. This dichotomy of rule versus practice began to make divers think and — horror of horrors — question the rule. And it was against this backdrop that many in the scientific diving community, led by former Smith-sonian Institution diving officer, Dr. Michael Lang, decided to explore the issue more fully. Putting various diving practices under a microscope is nothing new for Lang nor the scientiﬁc diving community. The American Academy of Underwater Sciences (AAUS), the organization that sets standards for scientiﬁc diving opera-tions, has long been a leader in examin-ing cutting-edge issues. In conjunction with other interested parties such as mil-itary and commercial divers, recreational diver training organizations, equipment manufacturers and dive industry publish-ers, AAUS has regularly co-sponsored important symposia exploring some of diving’s most fundamental practices. In 1988, they hosted what was probably the ﬁrst formal scientiﬁc discussion of dive computers. That was followed a year later with a workshop on the biome-chanics of safe ascents; and in 1991 they convened a symposium on safety con-cerns involving repetitive diving. In October 1999, the gauntlet was tossed once again, and in the impressive setting of the Capitol Mall, the Smithson-ian Institute, AAUS and DAN — along with additional support by DEMA (Diving Equipment and Marketing Association) and this magazine — sponsored a work-shop examining reverse dive proﬁles. I was fortunate to attend. Invited speakers comprised a Who’s Who of diving ex-perts. The group’s ﬁndings, listed in the sidebar, indicate that no signiﬁcant evi-dence was found to warrant a rule against reverse proﬁle diving. For those who’ve been diving for decades, this represents a substantial edit to the rulebook. One ﬁnal point shouldn’t be forgotten when rewriting the rules, however. Regardless of how decompression may or may not be af-fected by reverse proﬁle diving, let’s not forget an important safety implication that has an even more immediate conse-quence than getting the bends: When making a multilevel dive — as are most recreational dive proﬁles — common sense still dictates that it’s always best to be in the shallower portion of a dive when your air supply is low. So, the ques-tion still remains whether such a seem-ingly fundamental change in a rule will really make any practical diﬀerence in the way we dive. Only time will tell. I FLAMINGO DIVERS WEST CAICOS • FRENCH CAY • NORTHWEST POINT • SANDBORE CHANNEL Located on Venetian Road Tel/Fax 649 946-4193 Email: email@example.com • Web: www.flamingodivers.com Visit the Turks & Caicos Islands at www.WhereWhenHow.com MAY/JUNE 2017 • • • • • 99 “PROVO’S LITTLE DIVE SHOP” PRIVATE CHARTERS -SMALL GROUPS -8 Divers Max.