"When I was a teenager I was almost dashed, like so many ships, against the sharp granite of King Island: caught in a current, I struggled to swim against it, lost a flipper in the process, and was carried to a baroque-looking rock to which I clung and from where I eventually managed to extricate myself."It's summer at the bottom of the world, and time to go swimming. Here are some stories from creeks, rivers, seas, estuaries, straits and dams.