There are some Artificial Reefs in Georges River, Cooks River, the back of the Nepean and even Ropes Creeks ...give or take a few shopping trolleys amongst all those cars.

Calling a Spade a Wheelbarrow.

The use of these two words: Artificial Reef
are used to express a sense of dedication towards rectifying or improving the underwater environment by giving aquatic life a 'stimulus' akin to what 'natural' reefs provide.

The sinking of the Ex-HMAS Adelaide, uses these two words promotionally as the intention of dumping the wreck is for environmental reasons.
But in truth it is not the priority or true intention and reason for the dumping - it is a mere 'bonus' consequence of the intention for Tourism Dive Site dollars.
This is probably why the locals have protested regarding 'environmental concerns'.

>>>I'm gonna buy a gas guzzling smoke billowing big Ute, but hey, its an environmental vehicle with the small solar-panel on the top that boosts my decibal banging noise polluter!

So what I am saying is that they are drawing a line in the sand, when the tide is coming in - and that kinda smells wrong.