My father was UDT and went skin diving after the war.

[Captain O]

Once he went off the boat and down 20 feet. A man came down 20 feet with no Aqua-Lung, nor any equipment at all. Dad thought to himself, "What's this guy doing down here with no equipment?" Father went down to the "old timer's club" at 40 feet below the surface. The man with no equipment arrives right behind him in a matter of seconds. Dad scribbles on the "waterproof board", "What are you doing here without any equipment?" The man scribbles on the board "You fool, I'm drowning!"