A fascinating story in the NY Times Book Review about professional deep-sea divers: Diving Deep Into Danger.
It’s called “saturation diving”, and is not for the faint of heart:
“The best are those who have a great deal of confidence in themselves and their abilities,” one former diver, Phil Newsum, told me. “You have to be willing to adapt to any situation. Philosophically, when you go out on a dive job, you’re expecting something is going to go wrong.”
Often, because of the depth, the job is performed in the dark, with only a headlamp to light the way. Divers have told me stories of sudden encounters with manta rays, bull sharks, and wolf eels, which can grow eight feet long and have baleful, recessed eyes, a shovel-shaped snout, and a wide, snaggletoothed mouth. One diver sent me a video, filmed from a camera in the diver’s helmet, of an enormous turtle that was playing a game of trying to bite off the diver’s feet and hands every few minutes. The diver finally sent the animal swimming away by pressing a power drill to its head. Someone else sent me a photograph of a diver riding a speckled whale shark, as if on a rodeo bronco.
I didn’t even know this was possible. These guys live in a space-station-ish pressurized chamber for weeks at a time at whatever depth they’ll be working at. A thousand feet? Sure…
Once the divers are sealed inside the saturation complex, the air pressure is increased until it matches the pressure at the job’s working depth—this generally takes about a day. The breathing mixture inside the complex is also adjusted accordingly—the deeper the job, the more helium will be added to the breathing mixture. (Helium, besides allowing divers to avoid the risk of nitrogen narcosis, is easier to breathe under pressure because of its low density; it is also more quickly flushed from the organs and tissues than heavier gases.) This causes the divers to sound like Donald Duck, or children who have inhaled helium from balloons at a birthday party. But a diver inside the system doesn’t always realize that he sounds like Donald Duck, because the other members of the crew also sound like Donald Duck.
This condition is known as “helium ear.”
Read the whole thing.