This poem is named after the Mount Everest of SCUBA diving, the Andrea Doria, which sank in 1956. The wreck lies in about 250 feet of water, which is well beyond the 130-foot limits of recreational SCUBA.
At this depth (and starting at around 100 feet), divers breathing normal air, (air that has the same percentage of oxygen and nitrogen as at the surface), experience nitrogen narcosis, exhibiting similar symptoms to those of being drunk. This is due to the higher pressure of the water and of the air that they are breathing.
Modern day deep-wreck divers use trimix or heliox, air mixes in which some or all of the nitrogen is replaced with helium. This prevents narcosis because at depth, the nitrogen (and oxygen, if divers go deep enough) becomes toxic.
If you want to read more about deep-wreck diving and narcosis, I highly recommend the book Shadow Divers by Robert Kurson.
poem in text form under the cut
