This is a really interesting site, also part of Osprey reef.  It is named after an old anchor that became stuck in the middle of a swim through many years ago.  The anchor is upright and stuck right in the middle of the swim through.  This swim through is quite long and wide, in some places it is wide enough for 2 divers.  It starts at about 18m and after about 20-25m it finishes at 12m. There are wonderful bommies here as well.  Lovely schooling trevally and heaps of other tropical fish.