In the U.S., a commercial diver is generally considered to be a person who is paid to dive and work in an industrial environment, usually using heavy equipment. For example, divers who work in the offshore oilfields are considered to be "commercial divers." Divers who work to collect seafood, or who dive for science are not considered commercial divers but fall generally into the category usually called "professional divers." The difference here is the purpose of their dives. Saturation diving is a type of diving where the diver lives under pressure in a hyperbaric chamber, normally kept on the deck of a ship, and transfers to work on the bottom via a pressurized diving bell. When the bell reaches the depth where the diver is going to work, the bottom hatch on the bell is opened and the diver (using a helmet and umbilical attached to the bell) locks out and works, usually for about 4 hours. When they are done working they return to the bell, the hatch is sealed, and the bell is brought back to the surface and mated back onto the chamber. The diver may live under pressure and work this way for weeks at a time. Because the diver is living under pressure, he becomes saturated with the gas mixture he is using - usually helium and oxygen - and his decompression is the same whether he lives under pressure for a day or a month.
that training is fairly ineffective for real life conditions. When the dog falls through, followed by the kid you cannot stand on ice. Even when adults fall through you divers wearing 80 lbs of gear standing is ridiculous. And then put a tender standing right next to him! that's sport diving. nice to see tethers. pony bottles. Train on ice that is thin enough for a dog, a child, even an adult to fall through. Otherwise what is the difference between what we saw on the video and sport diving? Sadly - it's the training agency's fault, not the dive team.
