SS Yongala

The Yongala was a crack coastal liner, English-built in 1903 and running the Adelaide–Cairns route for the Adelaide Steamship Company. On 23 March 1911 she steamed north past the Dent Island lighthouse into a cyclone; wireless had been invented but her set had not yet been fitted, so the storm warning could not reach her. She vanished with all 122 people aboard — passengers, crew, and a racehorse named Moonshine whose body coming ashore was among the first evidence of the loss. For decades her fate stayed one of Australia's sea mysteries; a wartime sonar contact was finally confirmed as the Yongala in 1958. She lies on her starboard side on open sand miles from any reef, and that isolation made her an oasis: half a century of larvae drifting past had nowhere else to settle, and she is now routinely called the most life-dense wreck dive on earth. She is also a mass grave, protected by law, dived outside only.

How she sank: Lost with all hands in a cyclone off Cape Bowling Green, 23 March 1911.

Condition: Protected since 1981 under Australia's Historic Shipwrecks Act 1976, now the Underwater Cultural Heritage Act 2018: the hull is intact but softening, and divers are barred from entering or touching it. Moorings are mandatory; anchoring is banned.

Penetration: None. Entry is prohibited by law under her protected-zone status — and unnecessary: everything that makes this dive extraordinary lives on the outside.

Recommended certification: Advanced Open Water

Current: Strong · Visibility: 8–20 m

Marine life: Giant Queensland groupers, marble rays stacked under the bow, olive sea snakes, turtles, eagle rays, barracuda, snapper in walls, and trevally storms — with bull sharks passing in the cooler months.

Hazards: Open-ocean current that can run hard the full dive, exposed sea conditions on the crossing, and no sheltering reef; this is a strong-skills dive.

Commonwealth protected zone under the Underwater Cultural Heritage Act 2018; access via permitted operators and fixed moorings only.

She is the grave of 122 people; penetration, artifact disturbance, and anchoring are offenses.

Nothing may be touched or taken — the law and the dead both say so.