HMAS Brisbane

'The Steel Cat' earned her nickname the hard way: two gunline deployments to Vietnam, where her five-inch mounts fired thousands of rounds in shore bombardment, and a 1991 tour in the Gulf War made the Brisbane one of the Royal Australian Navy's most worked destroyers. Decommissioned in 2001 — her bridge and a gun mount went to the Australian War Memorial — she was prepared with unusual thoroughness and scuttled on 31 July 2005 a few kilometers off Mooloolaba on Queensland's Sunshine Coast, going down flat and upright in front of a spectator fleet. Queensland then did something rare: it declared the wreck its own conservation park, so access runs through permitted operators and fees fund her management. She sits upright and whole in about 28 meters, superstructure standing tall, with dozens of cut access points turning the hull into a honeycomb of legal, well-planned swim-throughs past mess decks, the operations room and the missile magazine. Colonization has been fast and gaudy — soft corals, kingfish and batfish over the deck, wobbegongs and moray eels inside, eagle rays and turtles on the sand — and she is now Australia's benchmark east-coast wreck outside the tropics.

How she sank: Deliberately scuttled as a dedicated dive site off Mooloolaba, Sunshine Coast, Queensland, 31 July 2005.

Condition: Upright and intact from sonar dome to gun mounts, with vigorous soft-coral growth; among the best-prepared reef ships anywhere

Penetration: Full With Training. Purpose-cut openings and mapped internal routes make guided penetration standard here; deeper machinery spaces still call for wreck certification and lights. Entering any overhead environment requires specific training — a wreck certification at minimum, technical wreck training for full penetration.

Recommended certification: Advanced Open Water

Current: Moderate · Visibility: 5–20 m

Marine life: Queensland grouper and estuary cod inside, wobbegong sharks on the deck plates, schooling kingfish and batfish above, nudibranchs on the guns, and turtles and eagle rays over the sand.

Hazards: Exposed-coast conditions, surge in the upper structure, and enough interior to lose count of exits without a guide

Ex-HMAS Brisbane Conservation Park — diving only through permitted operators, with fees supporting site management