My dad was a doctor on a small island, for a year. The islanders dived for sponges and pearls. They couldn't afford a decompression chamber, so if someone got D

My dad was a doctor on a small island, for a year. The islanders dived for sponges and pearls. They couldn't afford a decompression chamber, so if someone got DCS (after freediving too long) they dropped them off the side of the jetty with an old diving helmet, and a friend to keep them company, and pumped air down to them as they gradually re-ascended. Apparently it worked OK.