AD 2017 Q4
Alert Diver is the dive industry’s leading publication. Featuring DAN’s core content of dive safety, research, education and medical information, each issue is a must-read reference, archived and shared by passionate scuba enthusiasts. In addition, Alert Diver showcases fascinating dive destinations and marine environmental topics through images from the world’s greatest underwater photographers and stories from the most experienced and eloquent dive journalists in the business.
Alert Diver is the dive industry’s leading publication. Featuring DAN’s core content of dive safety, research, education and medical information, each issue is a must-read reference, archived and shared by passionate scuba enthusiasts. In addition, Alert Diver showcases fascinating dive destinations and marine environmental topics through images from the world’s greatest underwater photographers and stories from the most experienced and eloquent dive journalists in the business.
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in the case of repetitive deep<br />
dives, such as those conducted<br />
by freediving’s unsung heroes:<br />
competition safety divers.<br />
Unfortunately, no one knows<br />
exactly where the limits are. As<br />
one scientist put it, “Freediving<br />
is currently a data-free zone.”<br />
BACK TO THE FUTURE<br />
Perhaps the most exciting new<br />
development in freediving is<br />
prebreathing nitrox to extend<br />
bottom times or breathing 100<br />
percent oxygen postdive to<br />
shorten surface intervals and<br />
protect against DCS. Krack and<br />
his team provide predive nitrox<br />
and postdive oxygen to safety<br />
divers at PFI’s annual Deja Blue<br />
competition, which is regarded<br />
as the sport’s most sophisticated<br />
operation. PFI also uses nitrox to<br />
extend dive times — conducting,<br />
for example, 40-meter (130-<br />
foot) dives with three- to sixminute<br />
(and longer) bottom<br />
times during their recent Truk<br />
expedition, in what Krack calls<br />
“technical freediving.”<br />
Former world-record holder<br />
Eric Fattah, who invented<br />
the Liquivision F1 freediving<br />
computer, fluid goggles and<br />
the mouthfill technique, which<br />
enables divers to equalize at deep<br />
depths, is also an advocate of<br />
nitrox, which he has been using<br />
for freediving since 2009. Fattah<br />
is convinced that prebreathing<br />
nitrox not only increases bottom<br />
time but also can practically<br />
eliminate the risk of hypoxia.<br />
Currently there are no studies<br />
to delineate a freediving central<br />
nervous system (CNS) clock or<br />
oxygen tolerance unit (OTU)<br />
table. “It’s like the early days of<br />
tech diving,” Richardson said.<br />
“These are passionate adventurers<br />
operating by the seat of their<br />
pants and some theory. They’re<br />
the tip of the spear.” <strong>AD</strong><br />
ALERTDIVER.COM | 25
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