Cool - there must be a bit of steel infrastructure lying around post mining downturn that could be sunk offshore too!
Location to be a secret - somewhere between rotto and garden island - at 12.5m tall it wont be too hard to find! :-)

http://www.watoday.com.au/wa-news/fish-towers-to-be-sunk-off-perth-this-summer-to-help-bring-bumper-catches-20161208-gt6vn5.html