When my brother-in-law was a kid he made a diving bell from a 55 gallon drum and pumped air into it with a land-based compressor. Stuffed some cotton in the air line to filter out the oil and had a hole cut in the side of the drum with a plexiglas window in it. My husband says they probably had it down to over 25 feet at one point. He says he can't believe they didn't manage to kill themselves with it judging by the amount of oil that cotton collected 
Ber :lilbunny:

Ber :lilbunny: