The swimmer, Neddy Merril, is a rather pathetic figure.  Initially, he seems young and heroic.  However, as he continues on his journey home, we see him change quite a bit, especially after the storm hits.  After that point, he begins to seem old and pathetic.  It is after the storm too that the reader begins to learn more about Neddy and his current situation.  We learn that he has lost his money and that something has happened to his daughters.  At the end of the story, he appears old and completely bewildered.

His act of swimming from pool to pool all the way to his house mirrors his character's downward spiral.  Initially, it seems like a brave, macho thing to do.  He swims the first few pools effortlessly and is greated nicely by the owners.  However, once the storm hits, Neddy begins to weaken.  We see that his quest is really more of a drunken, pathetic joke.  Early in the story, it states how he never uses the pool ladders.  However, when he arrives at his former mistress's pool, he cannot lift himself out and must use the ladder. 

By the time he completes his swim, he is cold and exhausted and, quite literally, locked out of his own life.