Barrens Hut is claimed by many to be the best reef dive in Sydney.  I tend to agree.  It's absolutely covered in plant and fish life, visibility is excellent and it's easily accessible by boat.  We put the boat in at Dolans Bay in Lilli Pilli (just round the corner from Shiprock) and motor out of Port Hacking.  GPS co-ordinates we use are 34.08983^oS 151.17422^oE.  This puts us at the start of The Split which can be a dive of it's own. Using a bottom sounder we can quickly find the reef line and drop anchor right on top of the reef.  The sand is at around 26m and the reef rises sharply to less than 15m.  There are at lest 3 swim throughs, the best having a small cave entrance on the sandy bottom and then rising sharply like a chimney to the top of the reef.  PJs are common here in winter, we have seen a sunfish here as well.  There are always cuttles around and myriads of other fish.  Definitely a boat dive it is well worth it.