HMAS Karangi was a steel boom‑defence vessel built at Cockatoo Island and launched in 1941 to serve the Royal Australian Navy during World War II, performing boom‑laying and harbour defence duties including service at Darwin during the 1942 air raids. After naval service Karangi was decommissioned and sold for scrap; she was partially broken up and her remains were taken to Homebush Bay where the hulk was abandoned and left to decay among the bay’s industrial wrecks.

SS Heroic was a small tug built in the United Kingdom in 1924 and brought to Australia in the 1930s to tow colliers and work the coal trade, notably servicing routes between Hexham and Mortlake and supporting the Mortlake gasworks. The tug was retired to Homebush Bay where she was stripped and left to deteriorate.