Imagine...

Imagine a thick steel sphere whose interior is just 6 feet (2 meters) in diameter.  Imagine shoehorning yourself, a companion, and a whole bunch of equipment into this tiny space.  Then imagine that steel sphere is attached to a submarine.  You're floating just a few feet under the surface when something goes horribly wrong, and your now-broken submarine breaks free of the cable holding it near the surface and it plunges toward the bottom, about 1/3 of a mile (1,580 feet, or 480 meters) below.  As your steel sphere – the only thing keeping you alive – rushes down at speeds reaching 40 mph (60 k/h).  You have almost a minute to prepare yourself before it his the bottom, but when it does hit all hell breaks loose.  Your submarine embeds itself in a shallow gully on the bottom.  Equipment and supplies are all over the place, but you and your companion survive.  You have oxygen sufficient for just 72 hours of life, but basically everything else about your submarine is broken.  There's no way you can do anything at all that could get you back to the ocean surface.  What do you do now?

This really happened forty years ago, in August 1973.  I remember it well, especially the timing (just a couple of weeks after the last U.S. combat activity in the Vietnam War).  The plight of the two men trapped deep underwater made news headlines all around the world.  After an international effort got the right equipment and men to the scene, the helpless submariners were rescued.  When they were finally back on the surface and cracked their hatch, they had just 12 minutes of oxygen left.  It was that close.  I know that Hollywood would have made it 12 seconds, but in real life...that is really, really close to the edge.  The photo at right was taken just after a raft picked them up from their sphere...