Many thanks to Sandy McNab for providing the following photographs and commentary.  Please click on the images to enlarge.

D38 Photo1

Photo 1 was scanned from the local newspaper (pixels and all) showing the Perth being prepared off Seal Island in Frenchman's Bay (opposite Whale world) the week before the sinking. 

D38 Photo2.

Photo 2 is taken of the Perth about 0730 on the Saturday the 24th November awaiting the 0800 firing.  I was using my 100-300 camera lens from beyond a mandatory 1 kilometre 'no go zone'. Where we were to watch the sinking, I was panning over the top of and through many smaller boats in front of us. The ship looked a very sorry sight, and you could see daylight right through the lower decks where the outer hull diving access holes were opposite one another. 

D38 Photo3

Photo 3 is one of several I took shortly after the explosive charges were fired internally below the water line. I did not know how long the exercise was going to take. When the sea water flooded in, the resultant explosive's smoke from below was venting up through the many holes in the uppers and including the two stacks.

D38 Photo4.

Photo 4 a short while later. The ship took a minute or so to flood, sequentially from bow to stern 12 of the 14 charges were fired but two did not explode. The ship initially settled slowly from the stern, and then its buoyancy loss hastened. It was meant to be the other way and settle bows down for a final forward plunge to the seabed. Perhaps it was a couple of the forward charges that never detonated, making it stern heavy.

D38 Photo5.

Photo 5 is taken when it became obvious things were NOT going to plan. It was quickly settling astern and heeling badly to port, and then commenced a final rearwards plunge when total buoyancy was lost.

D38 Photo6

Photo 6 is taken after the port stern struck the seabed in about 30m of water. As the remainder of the 133m hull and keel length progressively landed on the seabed, it up righted itself.  The top of the mast remains a metre or two above the surface, and just two degrees off the vertical.  A perfect sinking, and it was all over in a couple of very quick minutes.