Moving with the Current                                -      N      - 
(-------------------------------------------------)     - <---(M)---> -
                                                        -      S      -

The current here is a nasty one, an incredibly strong undertow sucks you
under and carries you forward towards the north, at the same time on the
surface of the water you feel your legs being pulled in opposite directions
HARD.  You are stuck for a moment in mid current as both sides ply for your
body but eventually you continue on with the stronger one.