Water surged against my mask, jamming back my cheeks, when I clicked the steel controller on the torpedo I was riding, then I was propelled through the warm Caribbean water in one of the most bizarre -- and dangerous -- relay races on the planet.
This was Formula3Freediving. Never heard of it? That's because "Nightline" was invited to have an exclusive first look into this fresh new sport at its first race in the Cayman Islands last month.
F3F takes the existing sport of free diving -- diving as deep as you can on a single breath, already one of the world's most dangerous sports -- and turbo-charges it.
Six teams of four racers, plus alternates, each with a different team color, competed in three races. Each team has a "scooter," which looks somewhat like a boat propeller that racers put between their legs. After taking his one breath, the racer jumps onto the scooter, zooms through a marked race course located about 50 feet underwater, and then passes the scooter off to the next teammate who does the same thing. The team with the fastest combined times wins.
F3F was invented by Kirk Krack, the steely-haired guru of free diving. Krack (pronounced Krock) trained David Blaine for his 2006 "drowned alive" stunt and six world record-holding free divers.
He said he believes almost anyone who can swim and hold their breath can do the F3F race.
To prove his point he used me as a guinea pig. I started with static apnea, or a breath hold. My first try was pitiful, about 1:45. But after a few moments of instruction from Krack, I made it over three minutes.
Then we moved to a pool and tried the breathing exercise there. Krack guided me through a relaxation routine, and told me to begin ignoring the contractions of my diaphragm -- essentially my body's demand for air. With his coaching I managed a five-minute breath hold -- not bad, even for free divers.
So many divers push themselves to hold their breath underwater until they black out, causing drowning in great enough numbers that free diving and spear fishing are among the most dangerous sports in the world.
But it is the possibility of challenging evolution and taking the human body's natural capacity to adapt to unimagined realms (like the world record of a nearly 600-foot free dive) which most compels Krack to do this sport.
On the afternoon of the race the two dozen or so racers headed out to the Kittiwake, a shipwreck off coast of Grand Cayman. In their slick suits, they inspected the wreck like a school of fish with their undulating dolphin-like leg kicks.
A marked race course had been set up in advance for the divers, who swam to the starting gate. Suddenly they were off, banging against each other ahead of the first gate as if in an underwater chariot race.
But no sooner did the scooters hit the water than one of "Nightline's" go-pro cameras attached to them broke off and cracked into a propeller. We waited for an hour until a part was retrieved from shore.
As divers swam the course, some couldn't make it through the whole thing. Their lungs bursting, they came up for air.
The stakes for this race are small: a $1,000 pot. But the victor gets a lifetime's worth of bragging rights -- being the first winner of a brand new sport's first grand prix.
While this was F3F's maiden voyage in the Caymans, other races could soon sprout up in Ft. Lauderdale, Fla., Hawaii and California, Krack hopes.
"I think it has a good growth trajectory. And with some big sponsors. And I think we'll see it, we'll definitely see it as winter programming at some point," he said.
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A handful of scuba and free divers were watching on the sidelines, and I learned that one can get too close to the action. In one free dive, I accidentally drifted into the course, but a graceful female racer glided out of the way and back towards the gate.
When Team Purple won the event, the racers let out a rebel yell in victory.
Krack told me "I see teams that go to small race weekends, to get to the major grand prix, developments in the scooters and how they ride the scooters, and it'll be interesting."
In the Cayman Grand Prix, it was strange to see such a tranquility among the participants. There was no cheering or hot dogs during the race, just the thump-thump of my heart and the sight of those human-fish scooting by. That solitude became addictive.
"I'm 37 free dives from 7,000 in past three years alone," Krack said. "In three years, I've had over 230 hours free diving underwater."
I called him a "man-fish," he laughed. "Yeah, or a mer-man," he said.
For a few blissful minutes, I got to play mer-man as well, scooting through the water, through the gates, now also addicted.