Dryer
You had dive computers? I've never used one. Lets see I was 18 when i got my Naui card, which training is now the same training given Master Divers. Lets see, that was 1967. Nope, no computers dude. Memorized dive tables and a watch worked for me.

"space blankets" of course, I guess once again I was too far ahead of my time, but back then there WERE flying saucers to signal, you know they all left in 1977 right?
Jim