The "On the Beach" I saw was an earlier version -- not much in the special effects I suppose but powerful nonetheless. The story as I remember (this was a looonnngg time ago).

There had been a nuclear holocaust. These men were on a submarine and had therefore, survived. They were unsucessfully looking for any other life.

They kept picking up a Morse code message (Long time ago.. ) Hopeful there were in fact other survivors they hunted and hunted for it. Finally found it on the beach somewhere in the South Seas.

Remember those window shades with a ring on the end of a cord for raising and lowering the shade? An empty pop bottle had fallen into the ring and as the breeze blew the shade back and forth the bottle would tap.

The End.