It's called a Hawaiian backpack, and there still in use by the commercial spearfishermen at least on Oahu. They do repetitive deep bounce dives - some over 200+' - that absolutely defy the gas laws - and two guys will go through 8 or 10 steel 72's in a day. You or I would would be bent like a pretzel, but they're ok after years of this and a case of Budweiser.
It was a great rig for solo diving off a small boat - when you're done, all you had to was swing the metal harness straps over your gunwale and then climb in.
One thing you had to be careful of was that there was just the single waist strap holding it in place, so if you were heading straight down, the valve could crack you a good shot in the back of your head when the whole rig started racing you to the bottom. There was nothing as fast to rig out on when you're going diving, but one shot in the head was enough for me.
Strings picture of the guy in the Bouee Fenzy brought back some ancient yearnings - that rig was the absolute né plus ultra of dive gear in the 60's - I think they were something like $300 back then. They had a little air bottle that you could refill and use in an emergency. Cool stuff. Especially since all any of us had were those dinky aircraft survival vests.
