I don't know if you caught it last night's episode of BBC's human planet - Oceans. The show was all about how humans have and are adapting to the oceans and using them for our advantage, you can read more about by viewing the oceans page on the BBC website. There was a section in it about compressor diving in the Philippines which was absolutely amazing, a 100 strong crew dive down to depths of up to 40 meters breathing air pumped down through garden hose style tubes by an extremely dangerous looking compressor. These compressors weren't originally designed for diving but more commonly used for jackhammers. As such there is no reduction valve, just free flowing air. The diver literally puts the end of a garden hose style hose in his mouth and dives.
There is a team on the surface feeding the lines down in a hope that the lines don't get kinked and blocked. The idea is, they trail a net across the reef and then bring the sides up together to catch fish, they can make some huge catches this way but the risks are high. Divers regularly come up too quickly and get the bends. This comes as no surprise though as they do up to 4 dives a day at 20-40 meters of up to 4 hours at a time. Regularly racking up 25 dives a week. The only word I can describe this sort of diving with is madness but to them its a way of life and if you get the chance to watch the full version of the programme you will see what a tight nit community they are and how aware of the risks they all are as well. Here is a snippet from the show: