The iron‑hulled City of Adelaide, built by J&G Thomson in Glasgow, launched in 1864 and served Australian ports before becoming a coal hulk in 1902.
In 1912, a coal cargo caught fire, setting the hull ablaze; the blaze gutted the vessel and left it a smoking ruin.
George Butler of Magnetic Island bought the wreck in 1915 with plans to transform it into a breakwater or tourist lodging, but the tow to Picnic Bay failed when the ship ran aground at Cockle Bay in 1916.
Over the decades the wreck became part of local life: by the 1920s ABC reported swimmers using it for changing, while the 1942 RAAF training crash that killed four men underscored its lingering presence.
Cyclone Althea in 1971 further battered the deteriorating hull, yet sections survived, and by the 21st century mangrove roots have crept through iron beams, turning the wreck into a vegetated island.
Today the wreck is a protected heritage site; visitors are advised not to disturb it, as it provides crucial habitats for marine organisms, and it stands as a living testament to the intersection of maritime history and coastal ecology.